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Direct Metal Exchange in Carbonylcobalt Clusters.

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form)[''. Water elutes a byproduct, methanol/water (2 :3)
elutes compound (3h) (25%) followed by 1 4 ) (34%)l9I.
Received: February 13, 1980 [Z 665 IE]
German version. Angew. Chem. 93. 105 (1981)
P. F. Torrence. J. Carhohydr. Nucleosides Nucleotides 5, 187
(1978).
[2] H.-D Winkeler, F. Seela. Chem. Ber. 113. 2069 (1980).
131 L. L. Benner, Jr.. W. M . Shannon, P. W. Allan. G. Arnetr, Ann. N . Y . Acad.
Sci. 255, 342 (L975).
141 M . J. Robins, Y. Fouron. W. H. Muhs. Can. J . Chem. SS, 1260 (1977)
[Sl J. Daooll, 3. Chem. SOC.1960, 131
[61 R. Barker. H. J. Flefcher. Jr.. J. Org. Chem. 26. 4605 (1961).
[7J a) E. V. Dehmlow, Angew. Chem. 86, 187 (1974); 89. 521 (1977): Angew
Chem. Int. Ed. Engl. 13, 170 (1974); 16. 493 (1977); b) F. Seela, D. Winkeler.
ibid. 91, 570 (1979) and 18. 536 (1979).
181 C. A. Dekker, J. Am. Chem. SOC.87. 4027 ( 1 965).
191 (3b): m.p. 233-235 "C; TLC (silica gel. CHCI2/CH3OH 8:2): R, =0.42 UV
(CH,OH): h,,,=271 nm ( E = 1 1 600); 'H-NMR ([D,]DMSO): 6=3.67 (m, 5'H). 4.2-5.2 (m. 2',3',4'-H. 3 x H O ) . 6.07 (d, I'-H, J = 5 Hz). 6.68 (d. 5-H.
J = 3 Hz). 7.23 (s, NH2). 7.45 (d. 6-H, J = 3 Hz). 8.17 (s. 2-H); (46): m.p. (hydrate) 115--117"C, TLC (silica gel. CHCL,/CH,OH 8:2): R,=O35.
[ I ] E. De Clercq,
When (Id) was reacted with other cobalt clusters, similar
products were obtained e.g. with XCO,(CO)~ (X = CF,
CC6H5)theclusters (3a)and (3b) were formed, and the NiCo,cluster (34 was formed from C O ~ C O )and
, ~ ( l d ) in at least
twice the yield (50-90%) of the previously described processIS1.Table 1 gives the most important spectroscopic data of
the new compounds.
H3
Table I . Important spectroscopic data of the new hetero-cluster compounds. 'HNMR in C,D,. TMS int. std.. &values. IR in cyclohexane, v(Co) [cm '1.
Cmpd. 'H-NMR
(2c)
(2d)
(3a)
(36)
[4)
3 98, 3 76
4 76, 3 43
479
478
4 84. 4 68,
3 70
1R
2073 s, 2030 vs. 2020 vs. 1996 m. 1988 w. 1920 m
2078 m, 2038 vs, 2020 vs, 2009 m, 1994 w
2085 s, 2048 vs, 2030 vs. 2021 m, 201 1 w
2078 s. 2040 vs, 2020 vs, 2012 m. 1998 w
2053 m. 2034 s, 2005 m. 1990 vs. 1976 s, 1968 st. 1947 vw,
I934 m. I916 w, I898 vw. I870 vw
Direct Metal Exchange in Carbonylcobalt
Clusters[**'
By Harald Beurich and Heinrich Vahrenkamp['l
Experience so far indicates that it should be extremely difficult to devise a directed synthesis of a tetrahedral framework structure consisting of heteroatoms, since each corner
of the tetrahedron must be bonded to the remaining three
corner units. It is therefore all the more astonishing that
tetrahedral heteroatom clusters can be fromed indirectly
in one-step"] or in multi-step addition and substitution reactions by the systematic addition and incorporation of organometallic unit^''.^'. We now wish to report that these types
of organometallic expansion reactions can be performed by a
still simpler direct metal exchange process. In this connection, carbonyl cobalt clusters were reacted with simple binuclear carbonyl (cyclopentadienyl) metallic compounds (1)
which are present in equilibrium with their mononuclear radical moieties141.The latter species are able to attack the clusters and substitute the Co(Co),-units by organometallic
groups. The binuclear complexes (1) and CH&CO~(CO)~
react to produce the hetero clusters (2), of which we had already obtained (Za) and (2b) by the Co-As-elimination
method. The reactions are accelarated by thermal and photochemical stimuli and proceed in low yield in the case of ( l c )
and in high yield with an excess of (ld).
Fig. 1. Structure of (4). The most important bond lengths are as follows; Co-Mo
265.1 (4). Mo-Ni 255.7 (3). Ni-Co 233.6 (4). Co-C 187 (2), Mo-C 208 (2).
Ni-C 188 (2) pm [6].
L,M-MLn
( l a ) , MLn =
( I h ) , MLn =
I l c ) , MLn =
( I d ) , ML, =
['I
The chiral trimetal cluster (4) was obtained from
CH3CCo(CO)9 by a stepwise double metal exchange which
proceeds via (Za) or (Zd). Compound (4) spontaneously
forms optically active crystals, a structural analysis of which
was carried out (Fig. 1)[61; we have endeavored to obtain
larger single crystals of (4) so that a separation of them into
their enantiomers by manual selection can be carried out.
Furthermore, since the cluster compound (4) can readily be
prepared, it would be a suitable species with which to examine the process of optical induction in cluster catalysis reactions. This species should also provide definite proof that
cluster compounds, viewed as a structural whole, can be catalytically active"'.
MoCp(C0)s
WCp(CO)3
FeCp(C0)z
NiCpCO
f 2 a ) , ML, = M o C p ( C 0 ) z
Experimental
( 2 h ) , MLm W C p ( C 0 ) z
(Zc), MLm = FeCpCO
( 2 d ) , MLm = N i C p
A solution of (2a) (100 mg, 0.21 mmol) and (Id) (190 mg,
0.63 mmol) in 15 cm3 benzene was stirred for 5 d at 60°C.
Chromatography on a silica gel column (3 x 30 cm) using a
hexane/benzene eluent (9 :1) produced firstly (2a) (green),
secondly (Id) (red), and (4) (brown) as the third fraction. Recrystallization from hexane gave 20 mg (19%) of (4) as dark
brown crystals (19%) (m.p. = 152 "C).
Prof. Dr. H. Vahrenkamp, Dipl.-Chem. H. Beurich
Chemisches Lahoratorium der Universitat
Alberfstrasse 31. D-7800 Freiburg (Germany)
I*'] This work was supported by the Fonds der Chemischen Industrie and
by
the Rechenzentrum der Universitat Freiburg. We thank Dr P Merbach. Erlangen, for the mass spectra.
98
0 Verlag Chemie, CmbH, 6940 Weinheim, 1981
0570-08~3/8l/OlOl-0098$' 02.5010
Received. May 30. 1980 12 680 IE]
German version: Angew Chem 93, 128 (1981)
Angew. Chem. Int. Ed. Engl.
20 (1981) No. 1
CAS Registry numbers:
( I c ) , 12154-95-9; (Id). 12193-98-5: (2a), 68185-42-2; ( 2 ~ ) 76206-95-6;
.
(2d).
76206-96-7: (3a), 76206-97-8; (3b). 76206-98-9; (4). 76206-99-0 CH~CCO,(CO)U.
13682-04-7; C C ~ H # ~ O ~ ( C O13682-03-6;
)V,
CFC%(CO)U,18433-91-5
[ I ] S. A. Khartab. L. Marko, G. Bor. B. Marko. J. Organomet. Chem. I . 373
(1964).
121 P. C. Sleinhardr, W. L. Gladfeller. D. Harley, J. R. Fox, G L. Ge0flro.v. Inorg.
Chem I Y . 332 (1980).
[3] H. Beurrch. H. Vahrenkamp, Angew. Chem. 90. 915 (1978); Angew. Chem.
Int Ed. Engl. 17. 863 (1978).
I41 Th. Madach, H. Vahrenkamp. Chem. Ber. 113, 2675 (1980). and references
cited therein.
[5] A. T T Hsieh. J. Knrghl. J. Organomet Chem. 26. 125 (1971).
161 Orthorhombic. P2,2,2,, Z = 4 , a = 1194.8(4). b = 1705.2(2), c=9089(4) pm;
1343 Reflections. R = 0.065.
171 A Agapiou, S. E. Pedersen. L. A. Zyzyck. J . R. Norton, J. Chem. SOC.Chem.
Commun. 1977. 393.
Phenyl-Substituted Dirnethylenearnmoniurn Salts:
2-Aza-allenium Derivatives'**]
By Ernst- Ulrich Wiirthwein"]
Dimethyleneammonium salts ( I ) have been postulated as
intermediates['"-b1and were observed in mass spectrometric
fragmentationsii'], but little is known about their synthesis
and reactivityI2]. These linear 2-aza-allenium salts, which
have the topology and electronic structure of cumulenes, are
of considerable theoretical interest. They are novel examples
for the influence of positively charged, sp-hybridized nitrogen on charge distribution and structural preference. For organic synthesis the salts (1) can be used as highly reactive
C-N-C
synthons ("double" methyleneammonium or iminium salts), e.g. as electrophiles, dienophiles and as stable
precursors for nitrile ylides"bl.
R3
R1%. o_
/
R2
'R4
,C-h=C
SbCI,o
( l a ) , R', R 2 , R3, R4 = Ph
( l h ) , R', R2, R3 = Ph; R4 = H
( l c ) , R', R3 = P h ; R 2 , R4 = H
We report here a simple method for the synthesis of substituted dimethyleneammonium salts (1) which is applicable
not only to the known tetraphenyl derivative
but also
to the tri- and diphenyl derivatives (lb), ( f c ) and others. (lc)
is the first chiral representative of this class of compounds.
Starting materials are the easily accessible N,N'-bisalkylidenediaminomethanes (2) ("iminal~")['~, of which "hydrobenzamide" (Zc)13b1 is the best known. Acylium salts, powerful acylation reagentsl4], attack (2) at nitrogen and lead directly to (1). The N-acyliminium salts (3) could not be de-
P3
R'\
CH3C-O@ SbC1So +
,C=N-C-N=C,
I
R2
R4
tected as intermediates. ( l a ) and ( l c ) are isolated as crystalline solids when the reaction is performed in CHC13 or
CHC13/CC14 (1 :l), respectively, whereas ( l b ) is obtained as
an oil, which does not crystallize easily from CHC13/CC14
(cf. Procedure).
Apart from ( l ) , the cleavage of (3) yields the N-alkylideneacetamides (4), which are of theoretical and synthetic interest as reactive dienesl5"I and 1,4-dipole~[~~!
The driving
force which facilitates the formation of the highly reactive
dimethyleneammonium salts ( I ) is the strong acyl-imine
bonding in (4)16'.
The linear allene-like structure of (1) is especially evident
from the very intense cumulene-stretching bands in the IRspectrum, [v=1870 (la), 1890 ( l b ) , and 1910 cm-' ( l c ) ]
whose frequencies are similar to the corresponding absorptions in the allene spectrum. The planar, bent 2-azaallyl cation structure, (S), can therefore be ruled out as a valence
isomer of the cation (1 ') for (la), (1 b) and (1 c). Compounds
with amino-substituents in the 1- and 3-positions prefer the
ally1 form (S), however, because of the formation of the electronically favorable amidinium fragment^^'.'^.
The 'H-NMR signals for the cumulene protons in (lb) and
( l c ) occurs, as expected for methyleneammonium salts, at
low field: 6=9.8 ( l b ) and 9.4 (lc). The "C-NMR spectrum
of ( l c ) (CD3N02,70 "C) exhibits a triplet at 6 = 145.3 for C-1
and C-3 with an unusually large I3C-l4Ncoupling constant
(
= 16.3 Hz); comparable methyleneammonium salts
absorb at 6-170 ppm, and the corresponding allenes at
s=80-100.
Dimethyleneammonium salts (1) are valuable C-N-C
synthons in organic synthesis; they react rapidly and under
mild conditions with nucleophiles to give substituted N-methylimine derivatives (6),which in turn can be subjected to a
second, specific, nucleophilic attack at the imine group. The
salts (1) can be used as ene-partner in cycloadditions; deprotonation of the derivatives (lb) and ( l c ) with strong, non-nucleophilic bases leads to the nitrile ylides (7)i9', which cannot
be isolated, but give trapping products typical for this type of
1,3-dipole.
NuB
- H"
I
R',
R3
I
,C=N-C-Nu
R2
A4
R1
/
Cycloadducts
4
R2
NuQ= ORQ, NR?, CR3'etc.
(2)
Experimental
[*I
["I
Dr. E.-U. Wiirthwein
Institut fur Organische Chemie der Universitat Erlangen-Niirnberg
Henkestrasse 42, D-8520 Erlangen (Germany)
This work was supported by the Fonds der Chernischen Industrie. I thank
Prof. Dr. P. uon R. Schleyer for discussions and R. Kupfer. R. Neuferr and R.
Bauer for valuable experimental assistance.
Angew. Chem. Inr. Ed. Engl. 20 (1981) No. I
All operations were performed under a nitrogen atmosphere.
(lc): A solution of ( 2 ~(1.5
) g,
~ 5.0
~ mmol)
~ ~ in 20 cm3 dry
chloroform is treated with 0.4 g (5.0 mmol) acetyl chloride at
room temperature with stirring. The reaction mixture is
cooled to 0 "C and a solution of 1.5 g (5.0 mmol) antimony
pentachloride in 20 ml CHC13 is added dropwise. When the
addition is nearly complete a colorless precipitate forms.
This solid is filtered off under nitrogen after 3 h stirring in
the dark and is washed twice with 10 ml portions of CHC1,.
2.0 g (76%) of the white, microcrystalline, extremely mois-
Q Verlag Chemie, GmbH, 6940 Weinheim, 1981
0S70-0833/81/0101-0099
$ 02.50/0
99
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