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Complexes with Substituent-free Acyclic and Cyclic Phosphorus Arsenic Antimony and Bismuth Ligands.

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Complexes with Substituent-free Acyclic and Cyclic Phosphorus,
Arsenic, Antimony, and Bismuth Ligands
By Otto J. Scherer*
Dedicated to Professor Max Schmidt on the occasion of his 65th birthday
Until recently, phosphorus, arsenic, antimony and bismuth ligands were nearly always understood to be molecules such as R,E, R,E(CH,),ER,, and RC[(CH,),ER,],(E = P, As, Sb, Bi)
in which the lone pair of the atom E functions as a 2e donor. Current research interests,
however, increasingly involve substituent-free Enligands (n = 1 -6), the various types ofwhich
are mainly accessible via EX, (X = F,CI,Br,Ph), E(SiMe,),, (RAs),, P,S,, As,S,, gray
arsenic, and especially P, and As,; these ligands can be stabilized in the coordination spheres
of certain transition metal fragments. P,, As, and Sb, units with multiple M-E bonds are
found in bi- and trinuclear complexes; E, units can also be encapsulated (partially or completely) in cavities of a variety of metal cluster frameworks. Metallatetrahedranes with up to
three E atoms are especially common. Besides E, units, the greatest variety of coordination
modes is exhibited by E, ligands, which are found as intact tetrahedra and also as parts of
chains, polycycles, cubes and a trigonal prism. The phosphorus and arsenic species cyclo-En,
isoelectronic to the carbocyclic (CH), species, are suitable ligands for forming sandwich
complexes (n = 3,4, 5 ) and triple-decker sandwich complexes (n = 3, 5, 6). In addition to the
wide variety of chemical reactions, remarkable parallels are found in organic chemistry as well
as in solid-state chemistry for many of these substance classes. Some of the molecules have
received lively interest from theoretical chemists.
1. Introduction
fuji et al.,I51 and since cyclo-E, (E = P,As) had been stabi-
In a fascinating review article "Homonuclear Bonds Involving Main Group Elements" published in 1981,['] H. G.
von Schnering pointed out that insights into general chemical
principles can be hindered by too narrow a view of demarcated research interests. Links between the various chemical
disciplines of inorganic (solid state, main group, transition
metal chemistry), organic, and theoretical chemistry have
been forged as a result of two breakthroughs: first, the successful isolation in the 1980s of an unexpectedly wide variety
of molecules with ( p p ) x multiple bonds (both between elements of the first octet of main group elements and heavier
elements, and among the heavier elements alone), and secondly the concept of isolobal analogy (published by R.
Hoffmann in 1982[']) and its applications in organometallic
chemi~try.'~]
Such unifying concepts have proved ever more
powerful and have facilitated views of chemistry as an indivisible whole. A further useful heuristic principle is the diagonal relationship between carbon and phosphorus (C L P);
the expertise of Baudler and co-workersf4Iwas applied in the
synthesis of polyphosphanes P,H,+ , and (PH), , the analogues of alkanes C,H,,+, and cycloalkanes (CH,), ,and the
structurally impressive polycyclic organophosphanes with Pand PR-units, which are in turn isoelectronic and isolobal to
the fragments CH and CH, (CH, G PH,).
Since the N, analogue P, (P =P P HC = CH) had been
well-known and spectroscopically characterized and the first
kinetically stabilized diphosphene derivative, trans-RP=P-R (R = 2,4,6-tBu,C6H,), had been isolated by Yoshi[*] Prof. Dr. 0.J. Scherer
Fachbereich Chemie der Universitat
Erwin-Schrodinger-StraBe,D-6750 Kaiserslautern (FRG)
1104
0 VCH
VerlagsgesellschaJl mbH, 0-6940 Weinhelm. 1990
lized in sandwich complexes by Sacconi's group in Florence,@]and cyclo-P, (hexaphosphabenzene) in similar fashion by H . Sitzmann in this Institute,[71hope was nourished
that other En units (E = P,As,Sb,Bi), in particular En rings
isoelectronic to carbocyclic K systems (CH), ,could be stabilized in the coordination spheres of transition metal fragments. This review article describes the properties of ligands
composed of "naked" acyclic and cyclic En structural units
(E = N homologues) and aims to give an impression of the
momentum of research[*]in this novel and multidisciplinary
area.
2. El Ligands
2.1. Terminal Coordination (q*-E)
Phosphaalkynes R-C = P have been isolated and thoroughly ~tudied!~]In contrast, there is only indirect evidence
and speculation to support the existence of molecules with a
metal-phosphorus (or arsenic) triple bond (coordination
type 1).
L,,M=E
I (E = P, AS)
The trimetallaphosphatetrahedrane [W3(p3-P)(p-OR)3(OR),] (IOc), R = CH,tBu, may be formed from W,(OR),
and (RO),W =P.[loalThe co-photolysis of the Mo,As tetrahedrane [As{Mo(CO),Cp},] (10d) and [CpM(CO),], M =
Co,['Ob' Rh""' (cf. Section 2.2.2.3) allows the identification
of, inter aha, the products [Cp(CO),Mo = Mo(CO),Cp] and
0570-0833/90/1010-1104 S 3.50+ .25/0
Angew. Chem. Int. Ed. Engl. 29 (1990) 1104-1122
[Cp,(CO),Mo2(p,q2-As~)](33g). The formation of 33g has
been postulated to be the result of a fragmentation of 10d
into the two triple bond systems LMo = MoL (L = Cp(CO),)
and LMo = As (LMo
CH,P,As), isolobal to acetylene.
LMo =As could then give the isolated Mo,As, tetrahedrane
33g by dimerization.['ob'C1
-
2.2. Bridging Coordination
this, one observes a drastic high-field shift in the "P-NMR
spectrum (1 a -+ 2a: 6 = 816 46 = 172[""]). Both observations point to a strengthening of the Mn-E x-bond on going
from 1 to 2. The X-ray structure analysis of the Cp* derivative of 2b[llb1confirms both the stronger bond (d(Mn-As)
for 1 b(Cp') + 2b(Cp*) = 2.223 + 2.147 A) and the linear
geometry (Mn-As-Mn = 176.3(1)"), and thus, also the
formulation of the cation as an allene analogue, the
Cp*(CO),Mn moieties of which are rotated by 88.5" from
each other with respect to the Mn-As-Mn axis.
2.2.1. Doubly Bridging (p-E, Allene-like) [*I
The unusual linear two-coordination of type I1 was recently reported for the first time by Huttner et al.["]
The extremely hydrolysis-sensitive dimetallaphospha- and
-arsacumulenes 2 a[11a1and 2 b [ l l b l are obtained from the
phosphinidene or arsinidene complexes 1 a and 1 b by removal of hydride or chloride.
H
I
P
Cp*(CO),Mn
/-\
Mn(CO),Cp*
la
RX
- RH
[Cp*(CO),Mn=P=Mn(CO),Cp*]@Xe
za I1 1 a1
RX
=
2.2.2.1. Trigonal Planar E M , Framework
The trigonal planar geometry at an E l atom (E = P,As,Sb)
has been found in complexes of coordination type 111and IV.
I1 (E=P, As)
[L,M=E=ML,]@
2.2.2. Triply Bridging (p3-E)
MeO,SCF,, Ph,CPF,
III (E
=
IV (E = AS, Sb)
P, AS)
Characteristic for this bonding mode is an sp2-hybridized
E atom and ML, moieties capable of n bonding. Ideal starting compounds, which satisfy these conditions, are the halogen-containing phosphinidene, arsinidene, and stibinidene
complexes 3a-c, which give complexes of classes 4 and 5 by
substitution of the halogen on reaction with an organometallic nucleophile.[l2I
As
lb
[Cp'(CO),Mn=As=Mn(CO),Cp']@Xe
Substances 2 are typified by a shift of the n-x* transition
of starting material 1 to lower wavelength ( l a + 2a:
522 + 411 nm,[llal 1 b -+ 2b: 512 --t 380 nm[llbl).Parallel to
['I
Abbreviations: Cp = q5-C,H,, Cp* = q5-C,Me,, Cp' = q5-C,H,Me,
Cp" = qS-C,HiPr, Cp"' = q5-1,3-fBu,C,H3,Cpx = qS-C,Me,Et, triphos
= MeC(CH,PPh,),,
np3 = N(CH,CH,PPh,),,
py = pyridine; VE =
valence electrons, SEP = skeletal electron pairs.
3a (E = P, X = Br)
3b (E = AS, X = CI)
CI
I
E
/-A
(OC),Cr
Na[Mn(CO) ]
5_
Cr(CO),
3b (E = A S )
3c (E = Sb)
- NaCl
h;In(CO),
E
/-\
(OC),Cr
Cr(CO),
5 a (E =As) [ l Z a l
5b (E = Sb) '12a1
The five valence electrons of the E atom (E = P,As,Sb) in
the cyclic trinuclear clusters 4 a, b are involved in bonding
Otto 1 Scherer, born 1933 in Amberg (Bavaria),studied chemistry from 1955 through 1959 at
the Technische Hochschule Aachen and at the Universitat Miinchen, where he gained his doctorate in 1962 under the supervision of Max Schmidt. He then went as scientific assistant with his
supervisor to Marburg and to Wiirzburg. After his habilitation in 1967 at the Universitat
Wiirzburg there followed an appointment as dozent (1968) and the offer of a chair at the newly
founded Universitat Kaiserslautern. His research activities center on the study of the ligand
properties of lower coordinated phosphazenes and the coordinative stabilization of "naked"
phosphorus and arsenic ligands.
Angew. Chem. h i . Ed. Engl. 29 (1990) 1104-1122
1105
with two 16e fragments and one 15e fragment. To satisfy the
18e rule, a W-Cr bond is formed and CO eliminated. In the
acyclic complexes 5, the five electrons are distributed
amongst two 16e fragments and one 17e fragment. Complexes 5 correspond to a classical methylarsinidene or -stibinidene
in which the CH, group is replaced by
the isolobal Mn(COj, fragment. The extreme low-field
shift of the ,'P-NMR signal (6 = 945[""]), induced by
the planar p,-coordination of the phosphorus by three metal atoms, is characteristic of 4a. X-ray structure analysis
confirms for 4a, b"2",b1 and 5a1""] that the strongest
E-M bonds(4a,b: d(E-W) =d(E-Cr,,,) < d(E-Cre,,,);5a:
d(As-Cr) = 2.4412.42 A, d(As-Mn) = 2.52 Aj are those between E = P,As and the less electron-rich ML, fragment. In
solution, 5 a forms the cyclic trinuclear cluster 6 by decarbonylation, slowly at room temperature but rapidly at
80 oC,I12al
also shows a ,'P-NMR signal shifted to extremely low field
(6 = 977)."4'
2.2.2.2.Trigonal Pyramidal EM, Framework
This geometrical variant of p3-E coordination can be sub:
divided into complexes with or without metal-metal bonding between the ML, fragments. If each CH, group of the
main group molecules E(CH,), (E = P,Sb,Bi) is formally
replaced by an isolobal 17e ML, fragment, then the substance class 9 is obtained.
c[*]
d[*]
e
f
&![*I
h[*]
Sb
BI
Bi
Bi
B1
Bi
Fe(CO),Cp
Mo(CO),Cp(')
Mn(CO),
Fe(CO),(PPh,)(NO)
Fe(CO),Cp(')
Co(CO),
[15b, cl
V5dI
[15el
[15!J
[15gl
[15f, hl
[*I X-ray structure analysis
If 3c is allowed to react with the decacarbonyldimetalates
Na,[M,(CO),,] of the sixth subgroup (Group 6) in CH,Cl,,
the extremely air-sensitive salts 7 are obtained on removal of
the solvent and treatment with tetrahydrofuran."
The structural parameters of the chromium compound,
together with the intense color of the complexes 7,r12a1
show
the existence of a Sb-M(d - pjx-multicenter interaction.
The same planar p,-E coordination with E-M n-bonding
is observed in the E,M, butterfly frameworks of complexes
8a1I4]and 8b,['2"1 obtained from [Cp(CO),Mn(PBr,)] and
Fe,(COj, or photochemically from the Cp' derivative of
complex 42/27h1respectively (see Section 3.3).
A comparison of the X-ray structures of the isoelectronic
molecules 8 a and 8b, which contain different 14e ML,-fragments along the hinge, shows that the x-bonding component
in 8 a is clearly more strongly localized in the exocyclic double bond @(P-Mnj = 2.10, ;I(P-Fe) = 2.18 A). Like 4a, 8a
1106
The preferred synthesis of 9[15]involves the reaction of
EX, (X = F, most commonly CI, or Br) with the corresponding carbonylmetalates Na(K) [ML,]. In isolated cases," 5 f , h1
the binuclear complexes L,M-ML, (e.g. Co,(CO),) can be
used as the source of the 17e ML, fragment. The remaining
lone pair on E in 9 can react with S,, BF, . OEt,['5a1 and
M(COj,(thf) (M = Cr,W['5'1). Photochemical['5g1or thermal CO
can convert the "open" Bi clusters
9g and 9 h into the closed clusters 10, involving tetrahedrane
geometry and 15e ML, fragments.
2.2.2.3.
Tetrahedranes with E M , Core
All clusters of coordination type 10 possess 50 VE (valence electrons) and can be formally derived either from the
tetrahedral 60 VE molecule [Ir(CO),], or from the P4(E4)
tetrahedron (20 VE) by exchange of the isolobal units
P ( E j w I r ( C O ) , (in general a 15e ML, fragment).
['I
X-ray structure analysis
Angew. Chem. Int. Ed. Engl. 29 (1990) t104-tt22
The preparation of clusters 10 (for l o g and 10h see substance class 9) involves the use of PF,,['6a1 P4, or EX,
(X = Cl,Br,I; E = P,[10a-16b1As,[16C1Bi[16g1) or grey
arsenic['6d1as the source of the element E. The 15e ML,
fragments are obtained from IrC1,,['6a1 [Ir(CO)4],e[16g1
Co,(CO), or [ C O ( C O ) , ] ~ , [ ~ [C~(CO),MO],"~~]
~~.
or W2(OCH,tBu),(HNMe,),] .['oal With antimony, only anionic
complexes of type 10 are known, such as [(OC),Fe +- Sb{Fe(CO),},(p-H)]2e (10i),[16e1in which the Sb lone pair is
additionally coordinated to an Fe(CO), fragment. Starting
materials for this synthesis are [Sb{Fe(C0)4}4]3Q(16a) and
CF,S0,H.[16e1The structurally related 50 VE cluster anion
[Bi{Fe(CO),),(p,-CO)le (10j),['6f1which displays an extra
p,-CO cap, is formed from NaBiO, and Fe(CO), in methanol; its alkylation with CH,SO,CF, gives [Bi{Fe(CO),),(p,COCH,)], an uncharged BiFe, tetrahedrane with a p3methoxyalkylidyne ligand as 3 e donor." 7a1 A large number
of complexes 10 have been studied with respect to an extension of their coordination to the p4 type [(L,M),E-,
M'L,].['6b*1 7 b - f 1 Such clusters can be constructed in completely different ways, namely by reaction of [Cp(CO),Mn(PBr,)] with Co,(CO), or of [{(OC),Cr)2AsCI] with
Na[Co(CO),]; the products are the trimetallatetrahedranes
[{(OC),Co),E 4 M'L,], E = P, M'L, = Mn(CO),Cp and
E = As, M'L, = Cr(CO),.r17'1 A slight alteration of the reaction conditions between the arsinidene complex and Na[Co(CO),] leads to the cluster 11, for which the idealized
square-pyramidal geometry of the As,Co,Cr core was confirmed by X-ray crystallography[' 7el (cf. complex 14).
In the anion [(p-CO)(Fe(CO),),P -+ Fe(C0),lo, prepared
from [Fe4(CO),,JZe and PCI,, the 50 VE of the tetrahedrane
core are provided by three 14e Fe(CO), fragments, one
bridging CO, the P atom, and the negative charge.['7f1
10b['6b1and 10d[16c1tend to cyclotrimerize, retaining the
tetrahedral EM, core and eliminating three molecules of CO.
10et16d1
gives the cluster 12a, b, which has a trigonal bipyramidal core, on co-thermolysis with CpM(CO), (M =
Co,Rh).['Ob,"]
duce the p3-E caps (E = As and Sb as well as P) into the
clusters 13,['8a1compounds 3 are treated with Na,[Fe(CO),];
only in the case of 13a is a terminal Cr(CO), ligand replaced
by Fe(CO),.
[{(OC),Cr},ECl]
Na [Fe(CO) 1
13
3a-c
(E
=
P, As, Sb)
13
E
ML.
Ref.
P
P
P
P
As
As
Sb
Bi
[*I
X-ray structure analysis
13a-c are obtained in better yield from (OC),M(PX,)
(M = Cr,Mo,W; X = C1,Br) and Fe,(CO),.L18a1The remarkable conversion of trigonal planar coordinated p,-P
into p4-P is observed in the formation of 13d['8a1from 8a
and Fe,(CO),. 13d can be formally derived from 8 a by
bridging the two butterfly wingtips with an Fe(CO), fragment and forming two additional Fe-Fe bonds. The ML,free compound 13f has been known for a long time; it is
obtained from AsF, and Fe(CO), or from AsX, (X =
C1,Br) ['
and Na,[Fe(CO),]. Starting materials for the
cluster 13h,['8d1isoelectronic with 13f, and also for [Bi{M(CO),),Bi] (M = RU,OS),['~"]
are NaBiO, and Na[HFe(CO>,] or M3(C0)12(M = Ru,Os).
The reaction between [Bi{Fe(CO),}Bi] (13h)['8d1 and
[Fe(CO)4]2e leads to opening of an Fe-Fe bond and formation of [Bi,Fe4(C0),,]2e 14,[18'1a cluster anion of the nido
type (cf. complex 11) with a square-pyramidal Bi,Fe, core
(by X-ray analysis) and a terminal Fe(CO), group.
2.2.2.5. Cubanes with E4M4 Core
12 b additionally contains a CpRh(C0) fragment coordinated to the As lone pair.
2.2.2.4. TrigonaI Bipyramids with EM,E Core
The M, plane of the closo cluster type 13r'8a1is generally
composed of three 14e Fe(CO), fragments. In order to introAngew. Chem. Int. Ed. Engl. 29 (1990)1104-1122
Molecules whose core corresponds to a cubane (slightly or
considerably distorted) occupy a key position among transition metal clusters.['g1With elements of the fifth main group
(group 19, cubanes of the type A,B4 are preponderant (substance class 15).
Such molecules were discovered in 1970 by Dahi et al.JZoc1
who prepared 15e from Co(OAc), .4H,O and SbCl, in
methanol under CO/H, pressure. 15d'78d1and lSffZodlare
1107
If the pnicogen E is replaced by its heaviest homologues Sb
and Bi, complexes with different structures are obtained. The
reaction of SbCl, with [Fe(CO),]2e or [Fe,(C0),]2e leads
I,
I /
b
P
NCp'
WbI
E-MLto the multinuclear bispiro cluster [{ (OC),Fe,(p,-Sb)},C
As
NCp'
12W
{Fe(CO),},] (17e),[22'1the structure of which can be formal15'201
d
As
MoCp
ly derived from that of 17a by replacing the 3 e ligand X of
the latter by another 3e donor fragment, {(OC),Fe],Sb. 17e
possesses an SbFe,Sb core with butterfly geometry. The
spirocyclic core is also preserved in the Bi multinuclear cluster
[{(OC),Ru,)(p,-Bi)(p-H)Ru,(CO),,] (17f),[22d1
which is
formed in the thermolysis of [(C~MO(CO),},{~-(ASM~)~}]
synthesized
from
Bi(NO,),
.
5H,O
and
Na
[Ru,H(CO),,]
in
or [Bi{Co(CO),},] (9h); 15arZoa1
and 15b, c
[ in ~the ~
~
~
methanol.
The
role
of
3
e
bridging
donor
is
here
assumed
by
co-thermolysis of CpCo(CO), or [Cp'Ni(CO)], (Cp' =
p-H and an Ru(CO), fragment of the original Ru, starting
C,H,Me) with E, (E = P,As). 15e fragments isolobal to E
material.[22dl
are the preferred ML, fragments. Of the cubanes characterThe uncharged arsa-spirocycles Ma, b arise in the coized by X-ray structure analysis (15 a,[20a1
15e,[20c1
15f[Z0d1
)>
photolysis
of [{Cp(CO),Mo},(p,-As)] (10e)[16d1
and [CpM15a with its 14e CoCp fragment shows, as expected, the
(CO),] (M = Co,Rh),l'ob.clthe related cation 18c in the remost pronounced distortion. Four short P...P distances (av.
action of [CpCo(CO),] with AsF,
In these inorganic
2.57A) are observed in addition to the two very short
Co...Co distances (av. 2.50 A).[20a1
cp(Co),~\
M(CO)Cp
I ,As';l
2.2.3. Quadruply Bridging ( p 4 - E )
CP(CO)M
18
2.2.3.1. Tetrahedral EM, Core
This coordination type can be subdivided into polynuclear
complexes without (substance class 16) or with M-M bonds
(spirocyclic complexes, 17).
M(CO)C~
18a: M = Co, M' = Mo, n = 2 [ l O b l
18b: M = Rh, M' = Mo, n = 2
[18c]@:M = M' = Co, n = 1
spiropentane analogues, characterized by X-ray analysis, the
"extra" electron of H a , bat the spiro junction (As instead of
C) can be removed to the 15e molybdenum fragment; the
symmetric cation 18c has an As@spiro junction isoelectronic
and isolobal to C.
2.2.3.2. Square Bipyramidal EM4E Core
16
17
In the case of the anionic complexes 16, in the examples
known so far E is restricted to Sb and Bi, and ML, to
Fe(CO), and Co(CO),. [Sb{Fe(C0),},]3U (16a)[16'] can be
prepared from, e.g., SbCl, or SbCl, and Na,[Fe(CO),],
[Bi{Fe(C0),},]3e (16b)[""] from NaBiO, and Fe(CO), in
methanolic KOH. [Bi(Co(C0),),le ( 1 6 ~ ) ~is" formed
~~
from BiCl, and [Co(C0),le and in the reaction of [Cp,Co][Co(CO),] with [Bi{Co(CO),),] (9h) to form [Cp,Co][Bi{Co(CO),},] (16d),[2'I a paramagnetic complex with ten
electrons at bismuth. The tetrahedral environment of Sb and
Bi in 16a-16d was proved by X-ray structure analysis. The
structures of the cationic
[Sb(Fe(CO),(NO)(PPh,)},]@ and [Sb{Co(CO),(PPh,)),]@, however, have not
yet been determined.
Preferred ML, fragments in the substance class 17 are
Fe(CO), units. Thus, PX, (X = C1, Br), AsCl,, and iPr(H)PCH,PH, react with Fe,(CO), to form the spirocyclic complexes 17a-d.
If the trans positions of an octahedron with six 14e ML,
fragments are replaced by Sb or Bi atoms, the closo cluster
20b is obtained; this is the prototype of square pyramidal
p4-E coordination and possesses 7 SEP (skeletal electron
pairs).
20a: E = Sb, ML, = Fe(CO),; dianion
23b1
20b: E = Bi, ML,, = Ru(CO),
E
20
The dianion 20a, with additional terminal coordination at
Sb, is formed, inter alia, photochemically from 19, the p,-Sb
atom of which is coordinated by four Fe atoms in a distorted
tetrahedron.
,
"S b
(OC),Fe-Fe(CO),
19 I 2 3 a I
[*] X-ray structure analysis
1108
2Oa [23al
Whereas the four ruthenium atoms of 20 b, synthesized
from Bi(NO,), .5H,O and Ru,(CO),, ,lie in a p1ane,1'8e*23b1
Angew. Chem. Inl. Ed. Engl. 29 (1990) 1104-1122
the electron-richer anion 20a (8 SEP = n + 2 type) displays
a folded Fe,
The cis isomer of substance class 20
can be realized for the heaviest homologue of group 8.[lSe1
23
24
The cluster core of 20 c consists of an Os, butterfly bridged
by a Bi, unit (d(Bi-Bi) = 3.017(2) A, cf. Section 3). In the
cubic body-centered clusters 21 a, b (characterized by X-ray
analysis) all the faces are capped by p4-As ligands.IZ4".b1
The starting materials for the syntheses are [NiCI,(PPh,),]
and PhAs(SiMe,), or [Pd,(p,-S),Cl,(PPh,),]
and As(SiMe,), , respectively.
In the structurally more complicated macroclusters 22 a, b,
not only p,-As coordination but also face-linking p,-As and
connected tetrahedra with p,-As are observed.
I,,]
28
The source of the "naked" As atom is As(SiMe,), for 22a
and (PhAs), for 22b, which are allowed to react with [PdCI,(PPh,),] or [Co,(CO),J, respectively.
2.2.4. Clusters with Semi-interstitial P and Interstitial
E Atom ( E = P,As,Sb)
The partial or complete incorporation of El structural
units into open or closed metal polyhedra leads in the case of
P, to the clusters 23-32, which display a fascinating structural diversity (Scheme 1). If P, is replaced by its larger
homologues (covalent radii: P 110, As 121, Sb 141, Bi
146 pm), then sufficient space is only available for As, in the
singly or doubly capped square antiprism of Rh atoms (complexes 30b, 31 b) and for Sb, in the distorted Rh,, icosahedron (complex 32). In all clusters with semi-interstitial P,
butterfly fragments are present.
The solid-state structures of metal-rich phosphidesLZ6]
offer many parallels to the coordination polyhedra of 27-31.
X-ray structure analysis of the clusters [Os,(CO),,(p,-P)(pAuPPh,)] (27a)[25d1
and [Os,(CO),,(p,-P)(p-Cl)] (27 b),'25k1
prepared from 27 and Ph,PAu@ or FeCI, respectively, reveals that an intact triangle edge of 27 is bridged in 27a, but
in 27b an opened edge. Fenske-Hall calculations on Ru
model analogues of 27 and 27 b show the interaction of the
tangential CI atomic orbital with the antibonding Ru-Ru
LUMO of [Ru,(CO),,P]@ to be crucial; the cluster electron
count of 27 b is raised to 92!25k1 The longer metal-phosphorus bonds, as determined by X-ray methods, are indicated by
Angeuz. C'hrm. In[. Ed. Engl.
29 (1990) 1104-1122
Scheme 1. Schematic representations of the polyhedral skeletons of clusters
with semi-interstitial P(23-26) and interstitial P, As, and Sb atom (27-32)
dotted lines in the diagrams of clusters 23-26. In 30 and 31,
these are the Rh-P bonds to the
Temperaturedependent multinuclear NMR
show that both
the CO ligands and the polyhedral core are subject to fluxional processes; for 32 in solution, these dynamic processes
are rapid even at - 97 "C.
Sources of the El units are: [Cp(CO),MnPCl,J (for
23),1'8a1[Ru,(CO),(PPh,)(H)] (for 24, 26),[25a9c1
PCl, (for
25),125b1
[Os,H,(CO),,(PH)] (for 27))25d]red phosphorus
(for 28))25elHPPh, (for 29)[25'1 and Ph,E (E = P,As,Sb)
(for 30 -32).12sg - J1
1109
3. E, Ligands
3.1. p,q2 Coordination (4e Donor)
13h 118dl
3. I . I . Tetrahedranes with E2M 2 Core
The E, ligands P,, As, and Bi, (isoelectronic to acetylene
HC-CH) tend to form the tetrahedral clusters 33 with sideon coordinated E, ligands and 15e L,M fragments.
E
33
ML,
33 (E
=
[16b, 27aI
b
c
d
P
P
P
P
e[*]
P
f
As
g
As
As
a
P, As, Bi)
A tetrahedrane with two capped faces constitutes the
B,,C~,
of the paramagnetic anion 35,[16iI which is obtained, inter alia, by reaction of BiC-1, with [C~(CO),~O.
Ref.
LnM+MLn
E'
34 Ilsrl
h
i
Bi
Co(CO),
Cr(CO),Cp
Mo(CO),Cp
W(CO),Cp
W(OiPr),
Co(CO),
Mo(CO),Cp(*)
W(CO),Cp
Mo(CO),Cp(')
[27b]
[27c]
J
L
1841
(274
We, fl
"27g, h, 11
[27g,h]
[27Jl
The characteristic valence electron count of 40 for tetrahedranes 33 (nido type with n + 2 SEP) is attained in 34 with
the help of two electrons from the [CO(CO),]~.
[*I Contains another py ligand
3.1.2. Compounds with E2Mz Butterfly Cores
[{(OC),Co),(p,q2-As,)] (33f), the first representative of
this substance class, was prepared as early as 1969 from
[Co,(CO),] and
and characterized by X-ray structure determinations of its derivatives [Co,(CO), -"(PPh,),
(p,q2-As2)] (33f', n = 1, 33f", n = 2) (Table
The
sources of E, were (for phosphorus) P>16b,27b*c1
and PX,
(X = C1,Br,I)['6h1and (for arsenic) cyclo-(PhAs), ,[27g1 the
~(in 4c,~ W is ~replaced
~ by ,
p,-As trinuclear clusters 4b, c
Mo) and AS,S,.[~~']
33i is formed photochemically from
[Bi(Mo(CO),Cp'},] (9d).[15d1The 15e ML, fragments of
Cr, Mo, and W can conveniently be obtained by the following thermolysis reactions:
14e and 16e ML, fragments are typical of this type of
E,M, core 36.
E
36 (E
= P, AS)
~
36
E
ML,
Ref.
a
P
P
P
As
As
Ni(Et,PCH,),
Ni(PEt,),
Pt(PEt,),
Pd(PPh,),
Mn(CO),Cp*
[28a]
[28 bl
[28cI
Wbl
[28d]
b
c
d
~
e
Whereas 36e is formed by thermolysis of the arsinidene
complex [{Cp*(CO),Mn},AsH] !'*dl other representatives
of this substance class are synthesized from [CI,M(PR,),]
(M = Ni,Pt; R = Et;128b,c1
M = Pd, R = Ph[24b1)or [Cl,Ni(Et,PCH,),][28"1 and E(SiMe,), (E = P,As) or LIP(SiMe,), .128b,cJ
3.2. 6e-Donor E,-Ligands
33g, h 1 2 7 g 1
33g I 2 7 i l
M = Mo, n = 4, C p = Cp*
As well as the complexes 37, with additional terminal coordination of an E,M, tetrahedrane 33, star-shaped molecules 38 are known, in which the unusual p3-q2-E,coordination type has been verified.
The transfer of an E, unit of 33 is a remarkable reaction
type, for which only one example is known.[27d1
k
I M ( W (thOl
33%b, f, h
ICO,(CO),(P, +P2)I
33 a
[W,(OW,(PY),IJT
- PY
37 E
E-
-E*M(CO)s
M
' /
L"
> [W,(OiPr),(py)(~, q2-p2)1
33e
37
127dl
If the trigonal bipyramidal cluster 13 h is allowed to react
with [CO(CO>,]~,the edge-bridged tetrahedrane anion 34 is
obtained, formally by replacing an Fe(CO), fragment by
Co(CO), and simultaneously forming a Bi-Bi
(cf.
complex 14).
1110
-THF
1
/ \
ECI,
Na,w,(CO),ol
:
_ j
(OC),W'
%a: E = As
130aI;
b: E
=
/E\
x
Y
a
b
c
d
M ML,
Ref.
P Cr Co(CO), [29a]
P Cr Cr(CO),Cp [29b]
As Cr Co(CO),
[29c]
As W W(CO),Cp [27h]
38
5
'
WCQ,
Sb 130bl. c: E = Bi
[3OCl
Angew. Chem. Int. Ed. Engl. 29 (1990) 1104-1122
38c is formed in the reaction of (Me,Si),CHBiCl, with
Na,[W(CO),]; this reaction also gives rise to the edgebridged Bi2W2 tetrahedrane 39 a.130d1
The related As2W2
cluster 39b AS-As) = 2.305(10) A), with an iodine bridge,
is obtained from 38a and iodine.'27h]
The variant with bridging coordination is so far confined
to complex 41.
Cp(CO),Mo-Mo(CO),Cp
I%\
Complex 42, in which an As, ligand is coordinated to four
16e fragments, is formed by reductive coupling.'27h*
28d1
ek
3.3. 8e-Donor E, Ligands
[~CP(CO),M~I,A~C~I
Numerous complexes of type 40 are known; some examples are shown in the diagrams. The E,M, core coordinates
additionally through both E atoms to terminal transition
metal fragments. The complexes 40 can either be obtained
from the tetrahedrane precursor 33, or can be formed directly in the coordination sphere of the transition metals.
33 c
21cr(CO)s(thOl
1
- 2 THF
[CP(CO),M~A~{C~(CO),},I
+
E=p
I 3 1 a I .9
[{(OC),CrJ2PBrI
"OC),CJ-PX,l
= CI, Br
b. E
.
=
As
127hl
L(c0),c0-c0(c0),L
(OC),Md
X
a 7
M(CO),
40c, d
[CO,(CO),L,(P, q2-As2)1
Cr, L = CO [31b1 ;
40d: E = As, M = W, L = P(OMe),
4Oc: E = P, M
M~(CO),CP
AS-A~,
Cp(CO),Mn'
42
Mn(CO),Cp
127h. 28dI
X-ray structure analysis of 42 shows that both 3c,4eMn-AsIMn halves are rotated by 75.9" with respect to each
other and are thus incapable of conjugation. The As-As
bond length of 2.445(4) A (single bond) (cf. Table 1) and the
planar geometry at As indicate the presence of a diarsinidene
ligand <As-A$
3.4. Structural and Theoretical Aspects
PPh,
[co(co),]e
[WP(CO),M~},A~HI
Cp(CO),Mn,
+
=
12"1
2 IW(CO),(thf)l
The X-ray data (Table 1) show clearly that the E-E and
M-M bond lengths of the E,M, tetrahedrane unit undergo
only slight changes on going from a 4e(p,qZ)- to an
8e(p,q2"")-E2 donor ligand (e.g. 33a'/40c, 33c/41 and 33g/
40 b). The Bi-Bi bond becomes appreciably longer on going
from the uncharged tetrahedranes 33i (2.838(1)
and
39a (2.796(1) A)130d1
to the anions 34 (3.092(2)
and
35 (3.088(1) A)[16i1.
The side-on coordination of an E = E ligand leads, as expetted (and as was shown by EH calculations on N, com-
Table 1. '*P['H)-NMR data (6 values, J in Hz, 8 5 % H,PO, ext.) and E-E and M-M bond lengths [A] of selected examples with E,M, core
~
Compound
33a'
33 c
33 e
33f'
33 k!
33 i
36 a
36d
36 e
37 b
38 a
38b
3'P
-42.9(~)
133(q), 'J(PP)33.0
38C
40 b
40c
40d
41
42
- 78.5(~)
~~
E-E
M-M
2.019(9)
2.079(2)
2.154(4)
2.273(3)
2.31 l(3)
2.838(1)
2.121(6)
2.274
2.225(1)
2.052(2)
2.279(4)
2.663(3)
2.818(3)
2.310(3)
2.060(5)
2.28(1)
2.093(8)
2.445(4)
2.574(3)
3.022(1)
2.695(1)
2.594(3)
3.039(2)
3.167(2)
2.908(3)
3.46(M. .
4.02(M ..
2.996(1)
Ref.
3.064(3)
2.565(3)
2.59(2)
3.077(2)
[a] Two independent molecules in the unit cell.
Anzew. c'hem. Inl. Ed. Engl. 29 (1990) 1104-1122
1111
p l e ~ e s ) [ ~to' ~a lengthening of the E-E bond. In the tetrahedrane 33e (Table 1) the P-P bond is 0.26 A longer than in
uncomplexed P r P [d(P= P)exp= 1.894, d(P = P)calc=
1.896 A[331].The corresponding bond length in metal phosphides with P:" "dumbbells" is ca. 2.23
By means of EH calculations on the model substance types
[Co,(CO),E,] (E = P,PH and PCr(CO),), the criteria determining the choice of tetrahedrane or various butterfly geomAnalogous
etries were analyzed (compare 36 with 8a).r351
calculations for (L,W),As,, L = CO, suggest plausibly that
the E, ligand in complexes of type 38 uses its o bond pair as
well as the 471 electrons in bonding to transition
4.1.1. Reactivity of the cyclo-P, Ligand
The lone pair of each atom of the P, ring is, as expected,
capable of further c ~ o r d i n a t i o n7a*
. ~b1~
4. E, Ligands
4.1. Mononuclear Complexes with cyclo-E, Ligands
The substance class 43, the least metal-rich respresentative
of the tetrahedrane series [(L,M),-,En] (n = 1,2,3), contains
a cyclo-E, unit. The complexes 43a-h represent typical examples with widely differing ML, fragments (mostly 15e).
ik
E+
E'
43 (E
=
P, AS)
43
E
ML,
Ref.
a
b
c
d
P
P
P
P
P
P
As
As
Mo(CO),Cp
W(OCH,tBu),(HNMe,)
Co(CO),
Co(triphos)
Ni(triphos) [a]
NiCp*
Mo(CO),Cp*
Co(CO),
~ 7 ~ 1
[IOa, 36a]
[16bl
[6,36bI
[6,36b]
12W
e
f
g
h
In the complex [Cp*(CO),W(q 3-P,)(Mn(CO),Cp) ,]
(44d) (analogous to 44c), restricted rotation of the cyclo-P,
disk (T, z 330K, AG;= = ca. 56 kJ/mol) was demonstrated
by ,'P-NMR
Complex 43f reacts with
excess [Cr(CO),(thf)] to form [Cp*Ni(q3-P,)(Cr(CO),j,l
(44e).[20b1
While the P, ring remains intact when 43d is alkylated,[38"1one P-P edge is opened when the cationic complex
43e reacts with L2Pt(C,H,).[38b1
L = triphos
[27i]
[36cI
[a] Cation
L = triphos
As with the E,M, tetrahedranes, it was Dahfs group that
succeeded in the pioneering studies of this type of complex;
they synthesized [(0C),Co(q3-As3)] (43h)[36'1 from
(MeAs), and [Co,(CO),] at 200 "C under high CO pressure.
43a, c, g are formed together with the E,M, clusters
33a, c, g. 43 b l ' O a l and 1Oc are products of the thermolysis of
rW,(OCH,tBu),(HNMe,),] with P,, which is also (along
A
If the ethyl derivative of 45 is allowed to react with Co2@
and triphos, the binuclear product 47 contains EtP, , the
phosphorus analogue of ethyl azide, stabilized by coordinati~n.[~*"]
r
Et
1'"
47 1 3 8 C l
L = triphos
with P,S,) the source of P, for 43d, e; the (triphos)M moieties are obtained from [M(H,O),][BF,], (M = Co,Ni) and
triphos.[6*36bl Starting materials for the classical sandwich
complex 43 frZob1are [Cp*Ni(p-CO)], and P,.
1112
Angew. Chem. In!. Ed. Engl. 29 (1990) 1104-1122
and [Cp~Mo,P,S,]) during the co-thermolysis of
[Cp*(CO),Moj, and P4S3.[391
Characteristic for complexes 45-48 are the marked differences (as shown by X-ray methods) in the P-P and M-P
bond lengths (Table 2). The EtP, ligand displays a remarkable dynamic ring opening and closing behavior, as shown
by temperature dependent "P-NMR spectroscopy.
A particularly striking example of a cluster assembly reaction is seen in the reaction of [(triphos)Co(q3-P,)] (43d) with
CuBr, which results in the impressive multilayer sandwich
structure 49.[401The Cu,P, core, which may also be regarded
as a cuboctahedron, consists of a Cu, central deck and two
cyclo-P, decks (g(P-P) = 2.03(1)
If the Wade-Mingos electron counting rules for closo
deltahedra[,,] are applied to the triple-deckers 50 (which
conform to the classical 30/34e rule[431),then it is obvious
that only the 30e species 50d possesses the necessary 6 SEP
for a trigonal bipyramid (n + 1 type).
Cyclo-As, can also form part of a polynuclear cluster. In
[Co,(p,-As),@, ,q3-As,)L,j (Sl), synthesized from [Co-
Cl,L,] and PhA~(siMe,),,[~~]
the cluster core consists of a
Co, tetrahedron with three faces capped by As atoms and
with the fourth face extended to a n octahedron by an As,
ligand [d(As-As) = 2.463(2) A].
19
4.2. Binuclear Complexes with cyclo-P, Ligands
4.3. Spectroscopic, Structural, and Theoretical Aspects
The discovery by Sacconi et al. of the triple-deckers 50,
with a central cyclo-E, deck (E = P,As) was a milestone in
the studies of complexes with "naked" En ligandsL6]Typical
examples are SO a-f.K61
/
y\\
1
O0
LM--E-M'L
\
I//
E
50: E = P, As, L = triphos
50
E
P
P
c
P
d[a] P
e
P
f
As
a
b
[a] L
=
M
M'
n
VE
Ref.
Co
Ni
Pd
Co
Co
Co
Co
31
33
34
30
32
31
[61
Co
2
2
1
2
2
2
NI
Pd
Fe
Ni
[6]
16,411
[6]
[6]
[6]
MeC(CH,PEt,), to the Fe
The homonuclear representatives 50 a, b, c, fare prepared
from [M(H,O),]'* (M = Co,Ni) or [PdCI,(PBu,),], triphos
and E, (E = P,As)16] or As,S,.[~'] [(triphos)Co(q'-P,)]
(43d) can be extended to a triple-decker sandwich 50e by
reaction with the [(triphos)Ni]'@ moiety (generated as just
described); this is an impressive demonstration of the x-donor properties of the cyclo-P, ligand. Some of these complexes can be reduced to the monocation with NaBH,.[,] Complex 50a can be oxidized (30 VE) or reduced (32,33 VE)
cyclovoltammetrically.[61Complexes with 31 to 33 VE areL6],
with the exception of [(triphos)Ni(P,)Rh(triphos)]'@, a 32
VE complex with a strongly distorted P, central deck
[d(P-P) = 2.15-2.31 A[']], paramagnetic. In this complex
and the edge-opened 32 VE binuclear complex 47J38c1the
double degeneracy of the HOMO is removed by a JahnTeller distortion, changing the ground state from a triplet
to a singlet state.[,,
AnKen. Chem. In!. Ed. EnEf. 29 (1990) 1104-1122
In the mononuclear complexes 43, the strongest deshielding of the ,'P-NMR signal is observed for 43f (Table 2) and
[(triphos)Pd(q'-P,)]BF, (439, 6 = - 132.9(q).[36b1The signal is shifted by ca. 200 ppm to high field in the binuclear
complex 50c (Table 2). The very small 'J(MP) coupling constants [43b: 'J('83W31P) = 16 H Z , ~ ' ~[(triphos)Rh(q3"~
P,)] (43j): 1J(103Rh31P)
= 13 Hz[36b1]
indicate an essentially
x-bonded q3-P, ligand.
The X-ray structure analyses show that the average P-P
bond lengths of the mononuclear complexes 43 lie in a narrow range, 2.100-2.155& and that the extension of the
clusters to triple-deckers with a p,q3-P, central deck leads
only to a small increase in the bond length; this trend is also
recognizable in the few values available for the As complexes
(Table 2). The P-P bond length (2.183 A) in the bent, symmetric P, chain of the 19e radical anion P:e (in K4P3[471)
does not differ greatly (in contrast to the P-P-P angle) from
the average P-P bond length of the P, ligand in 47
(2.16 wr38c1)and48(2.20
The M " - M distancesofthe
binuclear complexes 50, with a central E, deck, lie in the
non-bonding range (Table 2).
Ab initio calculations for the 16e anion P," (an analogue
of azide, N,") indicate that the bent isomer is only slightly
less stable than the linear
EH calculations,[6.49a1 carried out for the model systems
[LM(p,q3-P3)MLlne,suggest that the interactions between
the xz and yz metal orbitals (e" combinations of the
L M - - - M Lsystem) and the z orbitals of the phosphorus (e"
set of the cyclo-P, fragment) are crucial. Analogous calculations were also carried out for the 32VE model compounds
[(H,P),M(EzS)M(PH,),]"e (E = P , A S ) . [ ~ ~ ]
1113
Table 2. "P{'H}-NMR data (6 values, J in Hz, 85% H3P0, ext.) and E-E and M-M bond lengths [A] of selected examples with E,M,,,, core.
Compound
3'P
E-E [a]
-351.5(s)
-205.2(s), 'J(WP)16
-276.2(m)
- 155.7(q), 'J(PP)14
-141.8(s)
2.127
2.155
2.141
2.122
2.100
2.375
2.372
43 a
43 b
43d
43 e
[CP(CO),M~P~I
[bl
[(Me2NH)(~BuCH,O),WP,1
[(triphos)CoP,]
[(triphos)NiP, ]BF,
43 f
43 g
43 h
[ChNiP31
"2%O),MoAs31
45
[(triphos)Co(P,Me)]BF4
- 121.0(t),
[(triphos)Ni(P,PtL,)]BPh,
'J(PP)362
-103.5(m)
46
- 342.2(d)
Ref.
[27c, 451
[lOa, 36a1
"3, 36bl
[6, 36bl
120bl
[27 i]
2 x 2.08(2)
1 x2.17(2)
2.17, 2.53(P...P)
[a] Average value (exceptions: 45, 47, 48). [b] Two independent molecules in the unit cell. [c] Standard deviations
material [Cp:Mo,P,S)]
5. E, Ligands
M-M
i0.01
A. [d] ABMX spin system Tor the starting
5.2. E, Ligands Formally Derived by Opening
Edges of an E, Tetrahedron
5.1. E, Tetrahedra (E = P,Bi) as Ligands
Of the three conceivable coordination modes of an E,
tetrahedrane, the terminal q I-P, and edge-bridging (side-on)
q2-P, coordination have been realized for phosphorus and
the face-capped variant q3-Bi, for bismuth. Starting materi-
52 l61
If one imagines three edges of an E, tetrahedron being
successively opened by 2e reduction, then the Zintl ions", "I
EO
:
(n = 2,4,6) are formally obtained (E = P,As,Sb,Bi).
53: L = PPh, Is''
E4
als for 52[61and 53[51](apart from P,) are the complexes
[(np),Ni] and [ClRh(PPh,),]; 54 is formed in the reaction
between [Bi{Fe(CO)3],(p,-CO)]e (10j)r'6'1 and C0.r521
X-ray structure analysis reveals characteristic differences
in the E-E bond lengths. Whereas the average PZp,-Pbas.
bond
length in 52 is 2.20A, 0.1 8, longer than the mean
Pbar,-Pbas.,[61
the difference in 54 is as high as 0.3 A (mean
Biap.-Bibas,3.47, Bibzs.-BibZs,
3.1 6 A). This trend is consistent
with the results of EH calculations for [Bi,(p3-FeL,),]2e.r521
The side-on coordination of the P, edge in 53, almost
perpendicular to the [(Ph,P),ClRh] plane, leads to an increased bond length of 2.462 & while the opposite bond is
significantly the shortest (2.1 88 A), and the others (mean
P-P 2.21 A) correspond to those of the P, molecule.r511EH
[61
calculations for the model complexes [(H3P)3Ni(~1-P4)]
and [(H,P),ClRh(P,)][51. 531 do not allow a clear distinction
between an intact $-P, edge or one opened by oxidative
addition (cf. complexes 55 and 56).1531
The cluster-like particles M,Sb, (M = Na,Cs), detected in
the gas phase, are suggested to possess a tetrahedral Sb,
core, surrounded by an alkali metal ~ c t a h e d r o n . ~ ' ~ '
1114
EZ0 (D)
EZO (F)
Scheme 2. Eie units derived from the E, tetrahedron. G E denotes one, =Ee
two, and -EZe three lone pairs.
If covalent bonding is assumed, the successive homolytic
bond cleavage of an E, tetrahedron leads to the uncharged
species corresponding formally to A-F (=E- forming two
bonds, - E- 3 - E forming one bond).
55 [56]
56 1561
As
E-Ni
CP'
57 [57]
58a: E = P [2Ob]
5 8 b E = AS [20b]
Angew. Chem. Inl. Ed. Engl. 29 (1990) 1104-1122
Of the Et0 units in Scheme 2, it has so far proved possible
to stabilize A, B, D and F in the coordination compounds 55
(A),[56156 (B),IS6]57 (D),[571
and 58 (F).[zObl
According to the
principle of isolobal analogytz1the complexes 56-58 can be
formally derived from tricyclo[2.2.0.0z~'Ihexane and the hypothetical molecules hexaarsaprismane and E,-cubane
(E = P,As) respectively [Cp(CO)Co w CH,, P w CH;
CpNi tst P,As] .
The analogy to cyclobutadiene,[621C,H,, and to the
allyl-like distortion of the d i a n i ~ n , ' ~
C,Hi',
~]
would lead
one to postulate the structures F and G for EZ'ze
(E = P,As t6,CH) (Scheme 3).
Scheme 3. E
The 31P-NMR[561and X-ray data for the cobaltatetraphosphatricycloalkanes 55 [d(P...P) = 2.61 A] and 56
[J(P...P) = 2.58 A] show, in comparison with 53,r511that a
single (to Pi") or double oxidative addition (to Pze) of P41561
has taken place. The suggested P4ze butterfly structure (A in
was
Scheme 2) for KzP, (detected by mass spectroscopy)r58a1
proved for HP," [58b1 by 31P-NMR spectroscopy.
The mean As-As bond length of 2.40 8, in the distorted
dinickelatetraarsaprismane 57[571
is slightly shorter than the
value of 2.44 8, in the distorted trinickelapentaarsacubane
58b.[Z0b1
The most remarkable feature of the structures of
the cubanes 58 is the tripod-like E, ligand, corresponding to
an E, tetrahedron with three bonds broken. This leads, as
expected, to a widening of the E-E-E angle from 60" to ca.
82"; the mean E-E bond lengths of 2.21 (58a) and 2.44 8,
(58 b)[zOblare however identical to those of P, or As, respectively. 58 a displays an interesting similarity to the solid-state
structure of La,Ni,P,, ,r591 in which sixteen P atoms formally constitute four trigonal pyramidal P:" units and the seventeenth functions as P3". The relevant Ni-P and P-P distances in both structures are essentially identical. The chemical bonding topology of binary and ternary transition metal
polyphosphides has been studied on the basis of edge-localized models.[60]
The synthesis of 56-58 is achieved by thermolysis of
[Cp*M(p-CO)], (M = C0,[561 Ni['Obl) and [Cp"Ni(pCO)]2r571
with P, or As,.
The only fragment so far capable of coordinatively stabilizing tetraphospha- or tetraarsacyclobutadienes is the 14e
fragment Cp*Nb(CO), . The Wade-Mingos electron count-
[Cp*Nb(CO),I
= CH,P,As.
A slight distortion of the planar P, base of 59a to a kite
shape is observed (the two P-P bonds approximately parallel
to the CO groups are slightly shorter).[611It is not clear
whether this is evidence for a formulation as cyclo-Pi" ligand G (dZ-Nb),because the distortion of an uncharged cycloP, ligand F (d4-Nb)could be caused by the different ligands
at the Nb atom.
that cyclo-P,, the
Theoretical investigations suggest
"antiaromatic" phosphorus analogue of cyclobutadiene,
should prefer the square arrangement with a P-P bond
length (6-31G* value) of 2.143 8, (average value in 59a
2.16 8,;r61a1).
In the series of square planar Zintl anions cyclo-E:"
(E = As,[651Sb and Bi[661),an As-As bond length of 2.35 8,
was found[651for cyclo-As:" (characterized by EXAFS
studies), which is in equilibrium with cyclo-As:e (cf. 2.38 8,
mean As-As in 59b161b1).
Similar planar cyclo-E, units are
found in the solid-state structures of (e.g.) CoE, (E = P,As;
~kutterudite-type))~~]
where the E, rectangles display appreciably longer E-E bonds (COP,
2.2412.34 A,
COAS,,'~~
2.47/2.56
~]
A). This type of molecule can be described either as an ionic or a covalent form.
(CO~@),(E:~),= CoE,
= Co,(E,),
If [Cp Rh(CO),] and P, are thermolyzed, then 61 [68bl and
are formed; in the latter, the
the binuclear complex 60r68a1
59a: E
= p l6la]
59b: E = ASI6Ib'
ing rules[441for the slightly distorted square pyramid E,Nb
in 59 lead to the necessary number of SEP (n + 2 = 7) for the
nido structure; the average E-E bond lengths (59 a
2.16
59b 2.38 8,['lb1) lie in the expected range for a
cyclo-E, ligand with sandwich-like coordination.
Angew. Chem. Ini. Ed. Engl. 29 (1990) ffO4-1122
60
U
61
Scheme 4. Conversion of 60 into 61 at elevated temperature.
1115
metallatetraphosphacyclopentadienemoiety itself acts as an
q4 ligand. 60 can be converted at 150 "C in xylene with cleavage of CO into 61 (Scheme 4).
The X-ray structure analysis of 60 shows that the planar
P, unit and the top Cp deck are arranged parallel to each
other, as in a sandwich.[68a1The almost equal P-P distances
(av. 2.15 A) contrast with those of the P, rectangle in the
binuclear sandwich complex 61,[68b1 with a short
(2.052(2) A; cf. Table 1) and a very long (2.845(2) A P . . P)
P-P distance (Rh
Rh = 3.324(1) A).
The mononuclear complex 62, prepared from
[CO(H,O),]~@,
P, and R,PCH,PR, ,[691 contains a zig-zagshaped q4-tetraphosphabutadiene central ligand moiety
with P-P bond lengths in the range 2.171 -2.197(3) A.
t . .
forms the common edge of two Mo,E, tetrahedranes. The
E, units [d(P-P) = 2.063(5)/2.071(5), d(As-As = 2.279(2)/
2.300(2) A, cf. Table I] approach each other in the phosphorus compound to within 2.849(5) 8, and in the arsenic complex 62c to 3.051(2) A. The bonding and nonbonding P-P
distances of 62a' and 61 are thus comparable. The structure
of 62 throws light on the
of the triple-decker
complex [(Cp*Mo),(p,q6-P,)] (68a)[71from 62a and white
phosphorus (see Section 7.1).
62a-c are formed together with other products in the
thermolysis of [Cp*(CO),Mo], or [Cp'(CO),Mo], and E,
or cyclo-(MeAs), 6 2 ~ . [ ~ ' ~ ]
(E=P, 62ac7]As 62b[71a,851)
6. cyclo-E, Ligands (E = P,As)
6.1. Sandwich Complexes
In 1987 the pentaphosphacyclopentadienide ion cyclo-P?,
isoelectronic to the classical cyclopentadienide ion C,HF,
was synthesized from white phosphorus P, and stabilized in
the sandwich complex [Cp*FeP,] (63a)[72
White phosphorus undergoes a ready insertion into the
Zr-P bonds of a bis(phosphido)zirconium complex under
very mild conditions, leading to the complex 63.[701
The four
remaining edges of the original P, tetrahedron have bond
lengths of 2.213 A (mean value for the P, triangle) and
2.241(4)
5.3. (E2)2
Ligands (E = P,As)
As well as the rectangular arrangement of two P, units
already discussed for the sandwich complex 61,[68bl
the alternative trapezium form of (E2)2has been realized in the binuclear molybdenum complexes 62. Single crystals of 62a suitable for an X-ray structure determination were obtainable
At about the same time[73a1Buudler et al. succeeded in
preparing stable solutions of MP, (M = Li,Na) from P, and
sodium in diglyme or from P4 and LiPH, in THF (Nap,/
[18]~rown-6/THF[~~".
"I). The products were characterized
by 31P-NMR and UV spectroscopy and by negative-ion
mass
(the same method demonstrated the
presence of PF in the spectrum of red phosphorus at
325 0C[741)and by conversion into 63a[73bl.
The anion cyclo-As?, prepared from yellow arsenic As,, is
to date the largest known 67c five-membered ring ligand, and
is suitable for constructing the sandwich complexes 63.[751
L"
63
FCo
62
E
L
Ref.
P
CP*
CP*
CP'
[71
[71 a, 851
[71 bl
63
d
e
f
g
As
As
co
L
62
only in the case of the derivative 62a', [Cp*(CO)MoP,{Cr(CO),)],.[7'"1 I n 62a' and 6 2 ~ the' plane
~ ~ of~ the
~
E, trapezium is perpendicular to the Mo-Mo axis
[d(Mo-Mo) = 2.905(1) (62a'), 2.950(1) 8, (62c)], which
1116
h
E
M L
Ref.
P
P
P
P
FeCp*
FeCp
RuCp*
RuCp
FeCp*
FeCp
RuCp*
RuCp"
[72a, 73b]
[72bl
As
AS
As
AS
[72bl
[72 bl
175aI
[75a]
[75bl
[75bI
The metallocenes 63, with a cyclo-E, deck, are mostly
stable thermally and towards air; like ferrocene, they are
typical nido compounds (n + 2 = 8 SEP) with a pentagonal
pyramidal core.
63a reacts with [Cr(CO),(thf)] or [CpMn(CO),(thf)] in
such a way as to utilize two (in
or even four (in 65[761)
of its lone pairs for further coordination.
Angenf. Chem. Int. Ed. Engl. 29 (1990) 1104-1122
6.4
65: [Cp*FeP5 I Mn (CO),CplLl
6.2. Triple-Decker Sandwich Complexes
Whereas the stacking up of 63 leads to the cationic, diaThe decamethylferrocene stacking reaction, discovered by
Rybinskuyu et al. for the synthesis of the 30 VE triple-decker
magnetic 30 VE complexes, the synthetic approach accordsandwich complex [(C,Hs)Fe(C,Me,)Fe(C,Me,)]PF6[771 ing to the following methods has so far only yielded the
can also be applied to 63 b and 63e.
L"
66
M
The mixed sandwich complexes 63 are formed by cotherAs[751) with [q5-CsMe4R)molysis of E, (E = P,!''l
M(CO),], (M = Fe,Ru) or [(q5-CsMe4R)Ru(CO),Br] (R =
Me,Et) .
W
63 b
L"
66
f
E
ML"
Ref.
P
P
P
CrCp*
CrCp
CrCp'
CrCp'
CrCp
MoCp
[78a]
1784
1784
178bl
178cl
As
As
As
WJI
27 VE species 66a-f. Possibly the preparation of 66f,[78d1
the only molybdenum compound of the series, depends on the
use of cyclo-(MeAs), instead of Pq[78a1
and
which
served as sources for the E, deck in the chromium complexes
(cf. the triple-decker complexes with cyclo-P, middle deck).
In both cases different Cp-substituted binuclear complexes
of the type [CpM(CO),], (M = Cr,Mo) are used to generate
the ML, fragments of 66 in the thermolysis reaction. The
photochemical conversion of [Cp (CO),Cr(q3-As,)] into
66e[78c1is also known.
Cyclovoltammetric s t ~ d i e s [ ' ~ show
~l
that the mixedvalence (d4/d5-Cr),paramagnetic (p = 2.07 pB[78']) 27 VE
triple-decker complex 66 a can readily be reversibly reduced
(28 VE species, Ere*= - 0.97 V) and oxidized (26 VE species, E,, = 0.07 V); the latter is possible even on the preparative scale with [Cp,Fe]@.[78'1
+
6.3. Spectroscopic, Structural, and Theoretical Aspects
-
669
66 h
The reaction of the Me$-bridged binuclear complex
[{ (C, Me,),SiMe,} Fe,(CO),(p-CO),] with P, in decalin
(1 2 h, 190 "C) leads to the "double sandwich" structure 67,
which can also, analogously to 66g, be further "stacked up"
at both P, rings.r791
Anger,. Chem. Inr. Ed. Engl. 29 (1990) 1104-1122
,'P-NMR studies show that the signal for the cyclo-P,
ring undergoes a continuous high-field shift upon conversion
of
b1 (6 = 470) into the sandwich and triple-decker
sandwich complexes (Table 3; e.g. 63a, b and 66g). The
average P-P bond lengths (see Table 3; determined by electron diffraction in the gas phase for [Cp*Fe(P,)] (63a),'''] by
X-ray methods for all other cyclo-P, sandwich complexes)
are all very similar and agree well with values from ab initio
calculations for cyclo-Py [2.081 8, (3-21 G*), 2.093 8,
(DZ + P)J181a*b1
and Nap, [2.093 8, (3-21 G*)].181a1
EH calculations for the model complexes (C,H,),Cr, (C,H,)CrP,,
[(C,H,),Cr12e, [(C,H,)CrP,I2@, (C5H5),Fe and (C,H,)1117
Table 3. ”P{’H}-NMR data (6 values, 85 % H,PO, ext.) and selected bond lengths [A] and angles [“I for sandwich and triple-decker complexes with a cyclo-EJigand.
Compound
3lP
E-E [a]
63 a
63 b
67
153.0(s)
152.8(s)
156.6(s)
63 d
64
66 g
84.8(s)
[CI
-15.5(s)
2.12
2.10
2.07
2.09
2.10
2.10
211
66a
63 f
66h
-290.5(s)
66d
66e
66 f
M-M
3.043(2)
2.19
2.32
2.33
2.727(5)
2.42
2.42
2.389(2)
2.762(3)
2.776(4)
2.773(2)
2.764(2)
3.074(3)
M-EsI,,,,,,,
M-CSI,,,,,,,
M-E-M [a1
1.55
1.53
1.54
1.54
1.65
1.58
1.52
1.52
1.36[a]
1.54
1.53
1.54
1.39[a]
1.39[a]
1.75(Cfi)
1.71(C$)
l.71(C8Me,)
1.71
1.85(C$)
1.72(C#)
1.69(Cp)
1.71(C$)
1.86[a]
1.715(CG)
1.68(Cp)
1.71(Cfi)
1.84[a]
1.85[a]
VE
18
18
18
18
18
30
80.6
72.5
27
18
30
75.6
27
27
27
68.0
67.8
[a] Average value. [b] Electron diffraction. [c] AMM’XX spin system. [d] Values for one of the two independent molecules in the unit cell. VE
electrons.
FeP, indicate that the compounds with cyclo-P,(,, ligands
are at least as stable as their carbocyclic analogues;[82]this
result has so far only been confirmed for [Cp*FeP,] (63a)
and other P, metallocenes with highly alkylated Cp ligands
(Table 3).
In all the sandwich and triple-decker sandwich complexes,
the five-membered rings are planar and parallel to each other. [Cp FeP,] (63 b) and [Cp FeAs,] (63 f) display nearly
identical pairs of distances from the iron atom to the centers
of the five-membered rings (Table 3). The appreciably shorter M-M distances (ca. 2.73-2.78 A) in the less electron-rich
27 VE triple-deckers (cf. ca. 3.05 A in the 30 VE species) leadto a compression of the pentagonal bipyramidal ME,M
framework (the angles M-E-M are ca. 8” narrower), accompanied by a lengthening of the average E-E bond length by
ca. 0.09 A (cf. 66g with 66a, and 66h with 66d, e in Table 3).
EH calculations for triple-decker compounds [CpM(p,q”-EJMCp] (n = 5, E = P,As; n = 6, E = P) with bonding M-M distances suggest[491that 28 VE should be the
magic number (cf. the 30/34e rule[431).If the electron count
is increased to 30, then two electrons must occupy the antibonding a’; (a*)orbital,[491which explains the experimentally established lengthening of the M-M bond length by ca.
0.3 8, (see Table 3).
[CpMo(As,)MoCp] (66f)[78d1
occupies a special position
among the triple-decker complexes 66d-f with a central As,
deck. The distortion H of the As, ring to an “allyl-ene”
system, of which this is surprisingly the only known example,
can be attributed to Jahn-Teller effects, as shown by EH
calculations.[49] In the 28 VE triple-decker [(CpMo),(p,q3-As,)(p,q2AsS)] (67),[83]the As,S middle deck (the ASS
part is disordered) displays the distortion in I, also consistent
with theory149a1(cf. the analogous triple-decker 48[391
with a
central P,S deck).
1118
Ref.
= number
of valence
If the Wade-Mingos electron-counting rules [441 are applied to substance class 66, then only the 30 VE triple-deckers 66g[761
and 66h[75a1have the necessary number of skeletal electron pairs for a pentagonal bipyramid (n + 1 = 8
SEP).
7. cyclo-E, Ligands (E = P,As)
7.1. Triple-Decker Sandwich Complexes
The molecules cyclo-P, (hexaphosphabenzene) and cycloAs, (hexaarsabenzene), isoelectronic to benzene (CH e
P,As) were first coordinatively stabilized in 198517] and
19891851
respectively, as the central decks of the triple-decker
sandwich complexes 68 a and 68i.
68a
0
I
V
W
68 i
Angew. Chem. In!. Ed. Engl. 29 (1990) 1104-1122
7.2. Spectroscopic, Structural, and Theoretical Aspects
The synthesis of 68 can involve the thermolysis of E,
(E = P,As) with [Cp~(”)M,(CO),](n = 4,6; M = M 0 ,r 7 * 8 5 1
WIE4]) or [Cp*(”)M(CO),] (M=VJE4] Nb,[61a,871)or the
photolysis of [Cp*( )(CO),Mo(q3-E,)] (E = P,ra61As[851).
L”
M
L”
68
68
e
f
g
h
I
E
M L*
Ref.
P
P
P
P
P
P
P
As
As
MoCp’
wcp+
vcp*
vcp
NhCp*
NhCp
NhCp”’
MoCp*
MoCp“
17,861
F341
[841
[841
[61a]
I61 a1
[871
[851
[851
The lowering of the valence electron number from 28 to 24
leads to an increasing low-field shift in the 31P-NMRsignals
of the cyclo-P, group in 68 and 69 (Table 4). Parallel to this,
an increasing distortion of the cyclo-P, ligand is observed by
X-ray methods. The separation of the benzene n system into
two allyl-like 3e units, just observable in the 26 VE tripledecker [CpV(C,H,)VCpJ:891 is particularly marked in the
cyclo-P, ligand of 68g; the central deck here (J) shows four
short (2.104(2)-2.116(3) A) and two very long (2.345(3) A)
P-P bonds (Table 4; cf. complex 68ff61a]).The presence of a
c y c 1 0 - P ~ligand
~
is also formally conceivable (resonance
for the series
forms K and L). LCAO-MO calculations~gO1
cyclo-P:Q (n = 0,2,4,6) with idealized symmetry 6/mrnm indicate the greatest stability for cyclo-Pz@.
For group 4 metals, the synthesis of 6918’] involves not
only CO elimination but also the removal of a Cp* ligand
from the mononuclear Ti complex.
P
pc-\p
2.34 I
p’-\pP
I 2.34
- 1
P<->P
P
L
K
J
f
I
P .e, P
‘P’
The 28 VE triple-deckers 68a, b and 6 8 i display within
experimental error regular phosphorus or arsenic hexagons;
the average E-E bond lengths are only slightly different from
those of the polyphosphides M4P6[”] (M = K,Rb 2.15 A;
Cs 2.14 A) and the polyarsenide Rb,As,[” (2.37 A), which
also possess a regular hexagonal ring, E t Q (1On system). The
marked enlargement of the central E, deck on going from
E =P (68a, b) to E = As (689, coupled with the almost constant Mo-Mo distance (Table 4), causes a flattening (decrease of Mo-E-Mo angle) of the hexagonal bipyramidal
Mo(E,)Mo framework.
If the chair-shaped P, ring in the distorted Ti,P, cubane
framework of 69[88]is attributed the formal charge cycloP;@ (isoelectronic with cyclo-S,), an interesting analogy to
the p , ~ ) ~ , q ~ - c y c l moiety
o - P ~ ~of Th,Pl
arises; the average P-P bond length and P-P-P angles of the latter compound are essentially the same as in 69 (2.23 A, 105.9°).[881
EH calculations[49] for the model compound [CpMo(P,)MoCp], as for the triple-decker complexes with a
central P, deck, indicate that the magic number of electrons
should be 28; the HOMO-LUMO gap (ca. 0.7 eV) is much
smaller here. The crystallographically determined average
P-P bond length of 68a, b (Table 4) is ca. 0.07 A longer
~j i
69
68 and 69 are thermally very stable and can be handled in
air.
Cyclovoltammetric studies CS41 show that the triple-decker
complexes 68a-c, with 28 or 26 VE, have a strong tendency
to form 27 VE complexes (open-shell configuration) by reduction (V complex 68c) or oxidation (W complex 68b). The
24 VE complex 69 is irreversibly oxidized to the 23 VE cation
and reversibly reduced to the 25 VE anion.1881
Attempts to prepare cubic P, from 69 and two moles of
PX, (X = C1,Br) have proved
Table 4. -”P{’H}-NMR data (6 values, 85% H,PO, ext.) and selected bond lengths [A] and angles [“I for triple-decker complexes with a central cyclo-E,-deck
______~______
68a
68b
68d
- 315,6(s)
- 338.2(s)
[Cp*Mo(P,)MoCp*]
~cP*w(p.5)wcP*l
CcP ’v(p6)vcP 1
160.3(s)
2.17
2.17
2.13
2.647( 1)
2.639(1)
2.627(2)
1.32
1.32
1.31 [a]
2.140(9)2.243(9)
2.104(2)2.345(3)
2.23
2.35
2.791(2)
1.395
1.40
1.41
Av,,,= 543 [b]
68f
[Cp Nh(P,)NbCp
“I
126.0(s)
68g
[Cp”’Nh(P,)NbCp”’]
113.4(s)
69
68i
[Cp*Ti(P,)TiCp*]
[Cp * Mo(As,)MoCp
386.7(s)
“1
[a] Average value. [h] 51V-NMR(VOCI, ext.): 6
=
Angew. Chem. Inr. Ed. Engl. 29 (1990) 1104-1122
2.818(1)
3.187(4)(M.-.M)
2.639(1)
1.32
2.0O(Cp*)
1.99(Cp*)
1.94 [a]
(CP )
2.08(Cpx)
2.O7(Cpx)
2.1O(Cp”’)
2.OO(Cp*)
1.98(Cp ” )
~~
62.8
62.5
63.2
28
28
26
17, 861
[841
[841
65.1
26
[61 a1
66.4
26
[871
58.7
24
28
I881
1851
60(sept), 1J(51V3’P)= 56 Hz.
1119
than indicated by ab initio calculations (6-31G*,
2.096 A)[64*81b.
92a,b1 for uncoordinated hexaphosphabenzene, cyclo-P,. Whereas cyclo-P: proves in every respect to
be the all-phosphorus analogue of C,HF, cyclo-P, differs
from benzene mainly in the framework properties (rather
than the x electronic effects).
8. Prospects
The coordinative stabilization of numerous substituentfree En units of phosphorus, arsenic, antimony and bismuth
has proved in some cases to be surprisingly simple. This has
led to a rapid growth of the interdisciplinary research area
within a short time. Parallel to these developments is an
increase in the number of examples that support the original
hopes of forging links to organic and solid-state chemistry.
It remains to be seen whether suitable synthetic strategies
can be developed (a) to stabilize cyclo-P, in sandwich complexes and ~ y c l o - P , ~
analogously
~,
or in triple-decker complexes and (b) to prepare polydecker sandwich complexes [931
or to stabilize coordinatively the uncharged As building
blocks of the interesting anions [ A S , C ~ ( C O ) , lg4]
] ~ ~ and
co [ R ~ { N ~ A S , } ]It~ ~
is .not
[ ~ ~too
~ wild a prediction that
clusters and cage molecules with cyclic and acyclic En frameworks will soon be discovered with ever increasing frequency. The attempts to illuminate the mechanistic aspects [27b1
should be continued, the cyclovoltammetric and magnetic
measurements intensified, and the study of catalytic properties taken in hand. The continued active interest of the theoreticians will be a great advantage.
M y particular thanks are due to the proficient and dedicated
co-workers, whose names are given in the references, and who
have worked in this (for us) new research area. We also thank
Prof. Kaim (Stuttgart) for spontaneously assenting to collaboration and Dr. G. Wolmershauser for constant and rapid assistance, readily given, in determining the many X-ray structures. Both have decisively influenced the progress of our
research. The Deutsche Forschungsgemeinschaft and the
Fonds der Chemischen Industrie gave generous financial assistance.
Received: March 29, 1990 [A 782 IE]
German version: Angew. Chem. 102 (1990) 1137
Translated by Professor P. G . Jones, Braunschweig (FRG)
111 H. G. von Schnering, Angew. Chem. 93 (1981) 44; Angeu,. Chem. In/. Ed.
Engl. 20 (1981) 33.
[2] R. Hoffmann, Angew. Chem. 94 (1982) 725; Angew. Chem. I n t . Ed. Engl.
21 (1982) 711.
[3] F.G. A. Stone, Angew. Chem. 96 (1984) 85; Angew. Chem. I n t . Ed. Engl.
23 (1984) 89.
[4] M. Baudler, Angew. Chem. 94 (1982) 520; Angew. Chem. Int. Ed. Engl. 21
(1982) 492; ibrd. 97 (1987) 429 and 26 (1987) 419.
[S] M. Yoshifuji, 1. Shima, N. Inamoto, K. Hirotsu, T. Higuchi, J. Am. Chem.
SOC.103 (1981) 4587; ibid. 104 (1982) 6167.
[6] Review article: M. Di Vaira, L. Sacconi, Angew. Chem. 94 (1982) 338;
Angew. Chem. Inr. Ed. Engl. 21 (1982) 330.
[7] 0. J. Scherer, H. Sitzmann, G. Wolmershauser, Angew. Chem. 97 (1985)
358; Angew. Chem. I n / . Ed. Engl. 24 (1985) 351.
[8] In the last five years alone, more or less extensive review articles have dealt
with several aspects of this field. 0. 1. Scherer, Angew Chem. 97 (1985)
905; Angew. Chem. Inl. Ed. Engl. 24 (1985) 924; W. A. Herrmann, ibid. 98
(1986) 57 and25 (1986) 56; 0 .J. Scherer, Comments Inorg. Chem. 6 (1987)
1; M. Di Vaira, P. Stoppioni, M. Peruzzini, Po!-vhedron6 (1987) 351; D.
1120
Fenske, J. Ohmer, J. Hachgenai, K. Merzweiler, Angew. Chem. 100 (1988)
1300; Angeu-. Chem. l n f . Ed. Engl. 27 (1988) 1277; K. H. Whitmire, J
Coord. Chem. 17(1988)95;N. C.Norman, Chem.Soc. Rev. 17(1988)269;
A:J. Di Maio, A. L. Rheingold, Chem. Rev. 90 (1990) 169. Most recent
comprehensive review: M. Scheer, E. Hermann, Z. Chem. 30 (1990) 41.
[9] Review article: M. Regitz, P. Binger, Angew. Chem. 100 (1988) 1541;
Angew. Chem. In/. Ed. Engi. 27 (1988) 1484; M. Regitz, Chem. Rev 90
(1990) 191.
[lo] a) M. H. Chisholm, K. Folting, J. W. Pasterczyk, Inorg. Chem. 27 (1988)
3057; b) M. L. Ziegler, H. P. Neumann, Chem. Ber. 122 (1989) 25; c) H. P.
Neumann, M. L. Ziegler. J. Organomet. Chem. 377 (1989) 255.
[ l l ] a) A. Strube. J. Heuser. G Huttner, H. Lang, J. Orgunomer. Chem. 356
(1988) C9; b) A. Strube, G. Huttner, L. Zsolnai, Angew. Chem. 100 (1988)
1586; Angew. Chem. Inr. Ed. Engl. 27 (1988) 1529.
1121 a) G . Huttner, U. Weber. B. Sigwarth, 0. Scheidsteger, H. Lang, L. Zsolnai, J. Organomer. Chem. 282 (1985) 331; b) G. Huttner, B. Sigwarth, J.
von Seyerl, L. Zsolnai, Chem. Ber. 115 (1982) 2035
[13] Review article: G. Huttner. K. Evertz, Ace. Chem. Res. 19(1986) 406; see
also: G. Huttner, K. Knoll, Angew. Chem. 99 (1987) 765; Angew. Chem.
Inr. Ed. Engl. 26 (1987) 743.
[14] H. Lang, L. Zsolnai, G. Huttner, Angew. Chem. 95 (1983) 1016, Angrnz.
Chem. Int. Ed. Engl. 22 (1983) 976; Angen. Chem. Suppl. 1983, 1451
[15] a) V. Grossbruchhaus, D. Rehder, Inorg. Chim. Acta 141 (1988) 9; b) W.
Malisch, P. Panster, Z. Naturforsch. 8 3 0 (1975) 229; A. M. Barr. M. D.
Kerlogue, N . C. Norman, P. M. Webster, L. J. Farrugia, Polyhedron 8
(1989) 2495; c) W. Malisch, P. Panster, Angew. Chem. 88 (1976) 680;
Angew. Chrm. In!. Ed. Engl. I S (1976) 618; d) W. Clegg, N. A. Compton,
R. J. Errington. N. C. Norman, A. J Tucker, M. J. Winter, J. Chem. SOC.
Dalfon Trans. 1988. 2941; e)J. M. Wallis, G. Miiller, H. Schmidbaur. Inorg. Chem. 26 (1987) 458; 9 W. R. Cullen, D. J. Patmore, J. R. Sams, rhid.
12 (1973) 867; g) J. M. Wallis, G. Miiller, H. Schmidbaur, J. Organomer.
Chem. 325 (1987) 159; W. Clegg, N. A. Compton, R. J. Errington, N. C.
Norman, Polyhedron 6 (1987) 2031; J. Chem. SOC.Dalton Trans. 1988,
1671; h) G. Etzrodt, R. Boese, G. Schmid, Chem. Ber. 112 (1979) 2574.
[16] a)T. Kruck, G. Sylvester, J. P. Kunau, Z . Naturforsch. 828 (1973) 38:
b) A. Vizi-Orosz, G. PBlyi, L. Marko, J. Organomer. Chem. 60 (1973) C25;
A. Vizi-Orosz, hid. 111 (1976) 61: c) A. Vizi-Orosz, V. Galamb, G. Palyi.
L. Marko, G. Bor, G. Natile, ibid. 107(1976) 235; d) K. Blechschmitt, H.
Pfisterer, T. Zahn, M. L. Ziegler, Angew. Chem. 97 (1985) 73; Angeu.
Chem. Int. Ed. Engl. 24 (1985) 66; e) S. Luo, K. H. Whitmire, Inorg. Chem.
28 (1989) 1424; 0 K. H. Whitmire, C. B. Lagrone, M. R. Churchill, 1.C.
Fettinger, L V. Biondi, rbid. 23 (1984) 4227; g) W. Kruppa, D. Blaser. R.
Boese, G. Schmid, Z . Naturforsch. B37(1982) 209; h) K. H. Whitmire, 1. S.
Leigh, M. E. Gross, J. Chem. Sor. Chem. Commun. 1987,926; i) S. Martinengo, G. Ciani, ibid. 1987, 1589.
[171 a) K. H. Whitmire, C. B. Lagrone, A. L. Rheingold. Inorg. Chem. 25
(1986) 2472; b)A. Vizi-Orosz, V. Galamb, G. Palyi, L. Mark&, J.
Organomel. Chem. 216 (1981) 105; c) R. La1 De, H. Vahrenkamp, Z .
Naturforsch. 8 4 0 (1985) 1250; d) A. Vizi-Orosz, V. Galamb, I. Otros, G.
Palyi, L. Marko, Transition Met. Chem. (Weinheim, Ger.) 4 (1979) 294;
e)H. Lang, G. Huttner, B. Sigwarth, 1. Jibril, L. Zsolnai, 0. Orama, J
Organomel. Chem. 304 (1986) 137; 9 A. Gourdon, Y Jeannin, ibid. 304
(1986) C1.
[18] a) H. Lang, G. Huttner, L. Zsolnai, G. Mohr, B. Sigwarth, U. Weber, 0.
Orama, I. Jibril, .
I
Organomet. Chem. 304 (1986) 157; b) L. T. 1.Delbaere,
L. J. Kruczynski, D. W. Mc Bride, J. Chem. SOC.Dalton Trans. 1973, 307,
c) T. Zimler, A. Vizi-Orosz, L. Marko, Transition Met. Chem. ( Weinheim,
Ger.) 2 (1977) 97, d) M. R. Churchill, J. C. Fettinger, K. H. Whitmire, J.
Organomet. Chem. 284(1985) 13;e) H. G. Ang, C. M. Hay, B. F. G. Johnson, J. Lewis, P. R. Raithby, A. J. Whitton, ibid. 330 (1987) CS, see also
[23 b]; 9 K. H. Whitmire, K. S. Raghuveer, M. R. Churchill, J. C. Fettinger, R. F. See, J. Am. Chem. SOC.108 (1986) 2778; K. H. Whitmire, M.
Shieh, C. B. Lagrone, B. H. Robinson, M. R. Churchill, 1.C. Fettinger,
R. F. See, Inorg. Chem. 26 (1987) 2798.
[19] C. D. Garner in B. F. G. Johnson (Ed.): Transition Metal Clusters, Wiley,
New York 1980, p. 265.
[20] a ) G . L. Simon, L. F. Dahl, J. Am. Chem. Soc. 95 (1973) 2175; b)O. J.
Scherer, J. Braun, G. Wolmershauser, Chem. Ber. 123 (1990) 471 ;see also:
0. J. Scherer, T. Dave, 1. Braun. G. Wolmerhauser, J. Organomet. Chem.
350 (1988) C20; c) A. S . Foust, L. F. Dahl, J Am. Chem. SOC.92 (1970)
7337; d) G. Ciani, M. Moret, A. Fumagalli, S. Martinengo, J Organomel.
Chem. 362 (1989) 291.
I211 a) M R. Churchill, 1. C. Fettinger, K. H. Whitmire, C . B. Lagrone, J.
Orgunornet. Chem. 303 (1986) 99; b) S. Martinengo, A. Fumagalli, G.
Ciani, M. Moret. ibid. 347 (1985) 413; c) J. S. Leigh, K. H. Whitmire.
Angew. Chem. 100 (1988) 399; Angew. Chem. Int. Ed. Engl. 27 (1988) 396.
1221 a) G. Huttner, G. Mohr, B. Pritzlaff, J. von Seyerl. L. Zsolnai. Chem. Ber.
115 (1982) 2044; b) D. J. Brauer, S. Hiefkamp, H. Sommer, 0. Stelzer, Z .
Naturforsch. 840 (1985) 1677; c) A. L. Rheingold, S. J. Geib, M. Shieh,
K. H. Whltmire, Inorg. Chem. 26 (1987) 463; A. M. Arif, A. H. Cowley,
M. Pakulski. J. Chem. SOC.Chem. Commun. 1987, 622, d) B. F. G. Johnson, J. Lewis, P. R. Raithby, A. J. Whitton, ibid. 1988, 401; e) C. F. Campana. L. F. Dahl, J Organomet. Chem. 127 (1977) 209.
Angew. Chem. Int. Ed. Engl. 29 (1990) 1104-1122
[23] a ) S. Luo, K. H. Whitmire, J: Organornet. Chem. 376 (1989) 297; b) C. M.
Hay, B. F. G. Johnson, J. Lewis, P. R. Raithby, A. J. Whitton, J Chem.
Soc. Dalton Trans. 1988, 2091
[24] a ) D. Fenske, K. Merzweiler, J. Ohmer, Angew. Chem. 100 (1988) 1572;
Ange-. Chem. Inr. Ed. Engl. 27(1988) 1512; b) D. Fenske, H. Fleischer, C.
Persau, ibid. 101 (1989) 1740 and 28 (1989) 1665; c) A. L. Rheingold, P. J.
Sullivan, J Chem. SOC.Chem. Commun. 1983, 39.
1251 a ) S. A Mc Laughlin, N. J. Taylor, A. J. Carty, Inorg. Chem. 22 (1983)
1409; b) P. Chini, G. Ciani, S. Martinengo, A. Sironi, L. Longhetti, B. T.
Heaton, J: Chem. SOC.Chem. Commun. 1979, 188; G. Ciani. A. Sironi, J.
Organomet. Chem. 241 (1983) 385; c) F. Van Gastel, N. J. Taylor, A. J.
Carty, Inorg. Chem. 28 (1989) 384; d) S. B. Colbran, C. M. Hay, B. F. G.
Johnson, F. 1. Lahoz, J. Lewis, P. R. Raithby, J. Chem. Soc. Chem. Commun. 1986,1766; e) G. Rosenthal, J. D. Corbett, Inorg. Chem. 27(1988) 53;
0 L. M. Bullock, J. S. Field, R. J. Haines, E. Minshall, D. N. Smit, G. M.
Sheldrick, J. Organornet.Chem. 310 (1986) C47; g) J. L. Vidal, W. E. Walker. R. L. Pruett, R. C. Schoening, Inorg. Chent. 18 (1979) 129; h) J. L.
Vidal, ihid. 20 (1981) 243; i) J. L. Vidal, W. E. Walker, R. C. Schoening,
rhid. 20 (1981) 238; j) J. L. Vidal, J. M. Troup, J. Organornet. Chem. 213
(1981) 351; k ) S. B. Colbran, C. E. Housecroft, B. F. G. Johnson, J. Lewis,
S M. Owen, P. R. Raithby, Polyhedron 7 (1988) 1759; I) B. T. Heaton, L.
Strona, R. D. Pergola, J. L. Vidal, R. C. Schoening, J Chem. Soc. Dalton
Trans. 1983, 1941
I261 D. E. C. Corbridge: The Structural Chembtry of Phosphorus, Elsevier,
New York 1974.
[27] a) C. F. Campana, A. Vizi-Orosz, G. Palyi, L. Marko, L. F. Dahl, Inorg.
Chem. 18 (1979) 3054; b) L. Y. Goh, C. K. Chu. R. C. S. Wong, T. W.
Hambley. J. Chem. Soc. Dalton Trans. 1989, 1951; c) 0. J. Scherer, H.
Sttzmann, G. Wolmershluser, J. Organomel. Chem. 268 (1984) C9;
d) M. H. Chisholm, K. Folting, J. C. Huffman, J. J. Koh, Polyhedron 4
(1985) 893, e) A. S . Foust, M. S. Foster, L. F. Dahl, J. Am. Chem. SOC.91
(1969) 5633; !)A. S. Foust, C. F. Campana, J. D. Sinclair, L. F. Dahl,
Inorg. Chem. 18 (1979) 3047; g)P. J. Sullivan, A.L. Rheingold,
Orgunometall~s I (1982) 1547; h ) G . Huttner, B. Sigwarth, 0.
Scheidsteger. L. Zsolnai, 0. Orama, ibid. 4 (1985) 326; i) I. Bernal, H.
Brunner, W. Meier, H. Pfisterer, J. Wachter, M. L. Ziegler, Angew. Chem.
96 (1984) 428; Angew, Chem. Int. Ed. Engl. 23 (1984) 438; j) W. Clegg,
N. A. Compton, R. J. Errington, N. C. Norman, Polyhedron 7(1988)2239.
[28] a ) H. Schdfer, D. Binder, D. Fenske, Angew. Chem. 97(1985) 523; Angew.
Chem I n t . Ed. Engl. 24 (1985) 522; b) H. Schdfer, D. Binder, Z. Anorg.
Allg. Chem. 546 (1987) 5 5 ; c) H. Schafer, D. Binder, ibid. 560 (1988) 65;
d) W. A. Herrmann, B. Koumbouris, T. Zahn, M. L. Ziegler, Angew.
Chem. 96 (1984) 802; Angew. Chem. Int. Ed. Engl. 23 (1984) 812; W. A.
Herrmann, B. Koumbouris, A. Schafer, T. Zahn, M. L. Ziegler, Chem. 5er.
118 (1985) 2472
[29] a) A. Vizi-Orosz, G. Pblyi, L. Marko, R. Boese, G. Schmid, J Organomer.
Chem. 288 (1985) 179; b) L. Y. Goh, R. C. S. Wong, T. C. W. Mak, ibid.
373 (1989) 71; c) M. Miiller, H. Vahrenkamp, ibid. 252 (1983) 95.
[30] a) B. Sigwarth. L. Zsolnai, H. Berke, G. Huttner, J. Organomet. Chem. 226
(1982) C5; b) G. Huttner, U. Weber, B. Sigwarth, 0 .Scheidsteger, Angew.
Chem. 94 (1982) 210; Angew. Chem. Int. Ed. Engl. 21 (1982) 215; c) G.
Huttner, U. Weber, L. Zsolnai, 2. Naturforsch. 537 (1982) 707; d) A. M.
Arif, A. H. Cowley, N. C. Norman, M. Pakulski, Inorg. Chem. 25 (1986)
4836.
[31] a) 0. J. Scherer, H. Sitzmann, G. Wolmershauser, Angew. Chem. 96 (1984)
979, Angew. Chem. I n t . Ed. Engl. 23 (1984) 968; b) H. Lang, L. Zsolnai, G.
Huttner, ibid. 95 (1983) 1017 and 22 (1983) 976.
1321 K. I. Goldberg, D. M. Hoffman, R. Hoffmann, Inorg. Chem. 21 (1982)
3863.
[33] For example R. Ahlrichs, S. Brode, C. Ehrhardt, J. Am. Chem. Soc. 107
(1985) 7260, and references cited therein.
[34] Review article: H. G. von Schnering, W. Honle, Chem. Rev. 88 (1988) 243.
[35] J.-F. Halet, JLY. Saillard, J. Organomet. Chem. 327 (1987) 365.
[36] a) M. H. Chisholm, J. C. Huffman, J. W. Pasterczyk, Inorg. Chim. Acto 133
(1987) 17; b) M. Di Vaira, L. Sacconi, P. Stoppioni, J. Organomet. Chem.
250 (1983) 183; c) A. S. Foust, M. S. Foster, L. F. Dahl, J. Am. Chem. Soc.
91 ( I 969) 5631.
[37] a) C . A. Ghilardi, S. Midollini, A. Orlandini, L. Sacconi, Inorg. Chem. 19
(1980) 301 ; b) C. Mealli, S. Midollini, S. Moneti, L. Sacconi, Cryst. Srruct.
Commun. 9 (1980) 1017; c) 0. J. Scherer, J. Schwalb. G. Wolmershauser,
Nen J Chem. 13 (1989) 399.
[381 a) G Capozzi, L. Chiti, M. Di Vaira, M. Peruzzini, P. Stoppioni, J. Chem.
Soc. Chem. Commun. 1986, 1799; b) M. Di Vaira, P. Stoppioni, M.
Peruzzini. Polyhedron 6 (1987) 351; c) A. Barth, G. Huttner, M. Fritz, L.
Zsolnai. Angew Chem. 102 (1990) 956; Angew. Chem. Inr. Ed. Engl. 29
(1990) 929.
[39] H. Brunner. U. Klement, W. Meier, J. Wachter, 0. Serhadle, M. L. Ziegler,
J. Ogunomet. Chem. 335 (1987) 339.
[401 F. Cecconi, C. A. Ghilardi, S. Midollini, A. Orlandini, J. Chem. Soc. Chem.
Commun. 1982,229.
[411 P. Dapporto, L. Sacconi, P. Stoppioni, F. Zanobini, Inorg. Chem. 20(1981)
3834.
[421 P. Stoppioni, M. Peruzzini, J. Orgonomer. Chem. 262 (1984) C5.
Angen. Chem. Int. Ed. Engl. 29 (1990) 1104-1122
[43] J. W. Lauher, M. Elian, R. H. Summerville, R. Hoffmann, J. Am. Chem.
Soc. 98 (1976) 3219.
[44] For example K. Wade, Adv. Inorg. Chem. Radiochem. 18 (1976) 1;
D. M. P. Mingos, Acc. Chem. Res. 17 (1984) 31 1.
1451 0. J. Scherer, H. Sitzmann, G. Wolmershauser, Acto Crysrallogr. Secr. C
41 (1985) 1761.
[46] D. Fenske, J. Hachgenei, Angew. Chem. 98 (1986) 165; Angew. Chem. h i .
Ed. Engl. 25 (1986) 175.
1471 H. G. von Schnering, M. Hartweg, U Hartweg, W. Honle, Angew. Chem.
101 (1989) 98, Angew. Chem. Int. Ed. Engl. 28 (1989) 56.
[48] J. K. Burdett, C. J. Marsden, New J. Chem. 12 (1988) 797.
[49] a) W. Tremel, R. Hoffmann, M. Kertesz. J. Am. Chem. Soc I l l (1989)
2030; b) E. D. Jemmis, A. C. Reddy, Organomerallics 7 (1988) 1561.
[50] M. Di Vaira, F. Mani, S. Moneti, M. Peruzzini, L. Sacconi, P. Stoppioni,
Inorg. Chem. 24 (1985) 2230.
[51] A. P. Ginsberg, W. E. Lindsell, K. J. Mc Cullough, C. R. Sprinkle. A. J.
Welch, J. Am. Chem. SOC.108 (1986) 403.
[52] K. H. Whitmire, T. A. Albright, S. K. Kang, M. R. Churchill. J. C. Fettinger, horg. Chem. 25 (1986) 2799.
[53] S. K. Kang, T. A. Albright, J. Silvestre, Croat. Chem. Acra57(1984) 1355.
[54] A. Hartmann, K. G. Weil, Angew. Chem. 100 (1988) 1111; Angew. Chem.
Int. Ed. Engl. 27 (1988) 1091, and references cited therein.
[55] Review article: H. Schlfer, B. Eisenmann, W Miiller, Angen. Chem. 85
(1973) 742; Angew. Chem. In!. Ed. Engl. I 2 (1973) 694.
[56] 0.J. Scherer, M. Swarowsky, G. Wolmershauser, Organomerallics 8 (1989)
841.
1571 0. J. Scherer, J. Braun, G. Wolmershauser, unpublished.
[SS] a) T. P. Martin, Angew. Chem. 98 (1986) 197; Angew. Chem. Int. Ed. Engl.
25 (1986) 197; b) M. Baudler, C. Adamek, S. Opiela, H. Budzikiewicz, D.
Ouzounis, ibid. 100 (1988) 1110 and 27 (1988) 1059.
[S9] D. J. Braun, W. Jeitschko, Acto Crystalfogr.Secr. 5 34 (1978) 2069.
[60] R. B. King, Inorg. Chem. 28 (1989) 3048.
1611 a) 0. J. Scherer, J. Vondung, G. Wolmershauser. Angew. Chem 101 (1989)
1395; Angew. Chem. Int. Ed. Engl. 28 (1989) 1355; b) 0.J. Scherer, J.
Vondung, G. Wolmershauser, J Organomer. Chem. 376 (1989) C35.
[62] Most recent review article: G. Maier, Angew. Chem. 100 (1988) 317;
Angew. Chem. l n f . Ed. Engl. 27 (1988) 309.
[63] B. A. Hess Jr., C. S. Ewig, L. J. Schaad, J. Org. Chem. 50 (1985) 5869.
[64] G. Ohanessian, P. C. Hiberty. J.-M. Lefour, J.-P. Flament, S. S. Shaik,
Inorg. Chem. 27 (1988) 2219.
[65] J. Roziere, A. Seigneurin, C. Belin, A. Michalowicz, Inorg. Chrm. 24 (1985)
3710.
[66] Most recent review article: J. D. Corbett, Chem. Rev. 85 (1985) 383.
[67] a) S. Rundqvist, N. 0. Ersson, Ark. Kemr 30 (1968) 103; b) A Kjekshus,
T. Rakke, Acra Chem. Scand. A28 (1974) 99.
[68] a) 0. J. Scherer, M. Swarowsky, H. Swarowsky, G. Wolrnershauser,
Angew. Chem. lOO(1988) 738; Angew. Chem. Int. Ed. Engl. 27(1988)694;
b) 0.J. Scherer, M. Swarowsky, G. Wolmershauser, ibid. I00 (1988) 423
and 27 (1988) 405.
[69] F. Cecconi, C. A. Ghilardi, S. Midollini, A. Orlandini, Inorg. Chem. 25
(1986) 1766.
1701 E. Hey, M. F. Lappert, J. L. Atwood, S. G. Bott, J. Chem. Soc. Chem.
Commun. 1987, 597.
[71] a) 0 .J. Scherer, H. Sitzmann, G. Wolmershauser, J. Organomet. Chem.
309 (1986) 77; b) A.-J. Di Maio, A. L. Rheingold, J Chem. Sac. Chem.
Commun. 1987, 404.
[72] a) 0. J. Scherer, T. Briick, Angew. Chem. 99 (1987) 59; Angew. Chem. Int.
Ed. Engl. 26 (1987) 59; b)O. J. Scherer, T.Briick, G. Wolmershauser,
Chem. 5er. 121 (1988) 935.
[73] a) M. Baudler, D. Duster, D. Ouzounis, 2. Anorg. Allg. Chem. 544 (1987)
87; b) M. Baudler, S. Akpapoglou, D. Ouzounis, F. Wasgestian, B.
Meinigke, H. Budzikrewicz, H. Munster, Angew. Chem. 100 (1988) 288;
Angew. Chem. Inr. Ed. Engl. 27 (1988) 280; c) M. Baudler, D. Ouzounis, 2.
Naturforsch. B44 (3989) 381
[74] J. T. Snodgrass, J. V. Coe, C. B. Freidhoff, K. M. Mc Hugh, K. H. Bowen,
Chem. Phys. Lett. 122 (1985) 352.
[751 a) 0. J. Scherer, C. Blath, G. Wolmershauser, J Organornet. Chem. 387
(1990) C21; b) 0. J. Scherer, C. Blath, G. Wolmershauser, unpublished.
I761 0. J. Scherer, T. Bruck, G. Wolmershauser, Chem. 5er. 122 (1989) 2049.
1771 A. R. Kudinov, M. I. Rybinskaya, Y. T. Struchkov, A. I. Yanovskii, P. V.
Petrovskii, J. Organomet. Chem. 336 (1987) 187.
I781 a) 0. J. Scherer, J. Schwalb, G. Wolmershauser, W. Kaim, R. Gross.
Angew. Chem. 98 (1986) 349; Angew. Chem. I n t . Ed. Engl. 25 (1986) 363;
b) 0.J. Scherer, W. Wiedemann, G. Wolmershauser, J: Organomet. Chem.
361 (1989) C11; c) 0. J. Scherer, W. Wiedemann, G. Wolmershauser,
Chem. 5er. 123 (1990) 3; d) A. L. Rheingold, M. I. Foley, P. J. Sullivan, J.
Am. Chem. Soc. 104 (1982) 4727; e) W. Bronger, private communication;
0 J. Schwalb, Dissertation, Universitat Kaiserslautern, 1988.
[79] 0.J. Scherer, A. Schneider, unpublished.
[SO] R. Blom, T. Bruck, 0.J. Scherer, Acra Chem. Scand. 43 (1989) 458.
[81] a) T. P. Hamilton, H. F. Schaefer 111, Angew. Chem. 101 (1989) 500;
Angew. Chem. Inr. Ed. Engl. 28 (1989) 485; b) R. Janoschek, Chem. 5er.
122 (1989) 2121.
1121
[82] M. C. Kerins, N. J. Fitzpatrick, M. T. Nguyen, Polyhedron 8 (1989) 1135.
(831 A:J. DiMaio, A. L. Rheingold, Inorg. Chem. 29 (1990) 798.
[84] 0. J. Scherer, J. Schwalb, H. Swarowsky, G . Wolmershauser, W. Kaim, R.
Gross, Chem. Ber. 12f (1988) 443.
[a51 0. J. Scherer, H. Sitzmann, G. Wolmershiuser, Angew. Chem. 101 (1989)
214; Angew. Chem. Int. Ed. Engl. 28 (1989) 212.
[86] P. Jutzi, R. Kroos, Chem. Ber. 121 (1988) 1399.
[87] 0. J. Scherer, R. Winter, unpublished.
[88] 0.J. Scherer, H. Swarowsky, G. Wolmershauser, W Kaim, S. Kohlmann,
Angew. Chem. 99 (1987) 1178; Angew. Chem. Int. Ed. Engl. 26 (1987)
1153.
I891 K. Angermund, K. H. Claus, R. Goddard, C . Kruger, Angen,. Chem. 97
(1985) 241; Angew. Chem. Int. Ed. Engl. 24 (1985) 237, and references cited
therein.
1122
[90] H. G. von Schnering, T. Meyer, W. Honle, W. Schmettow, U. Hinze, W.
Bauhofer, G. Kliche, 2.Anorg. A&. Chem. 553 (1987) 261, and references
cited therein.
(911 H. G. von Schnering, M. Wittmann, R. Nesper, J. Less-Common Met. 76
(1980) 213.
[92] a) S. Nagase, K. Ito, Chem. Phjs. Lert. 126 (1986) 43; b) M. T. Nguyen,
A. F. Hegarty, J. Chem. SOC.Chem. Commun. 1986,383. For MNDO-calculations see: N. C. Baird, Can. J. Chem. 62 (1984) 341
[93] Review article: W. Siebert, Angew. Chem. 97 (1985) 924; Angew. Chem. Inr.
Ed. Engl. 24 (1985) 943.
[94] B. W Eichhorn, R. C . Haushalter, J. C. Huffman, Angew. Chem. f01
(1989) 1081; Angew. Chem. Int. Ed. Engl. 28 (1989) 1032.
[95] H. G. von Schnering, J. Wolf, D. Weber, R. Ramirez, T. Meyer, Angew.
Chem. 98 (1986) 372; Angew. Chem. Int. Ed. Engl. 25 (1986) 353.
Angew. Chem. In!. Ed. Engl. 29 (1990) 1104-1122
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