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HalogenonitrosylmolybdatesЧIsolation of the First Classical MoI Complex.

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CAS Registry numbers:
( 4 ) , 119-53-9; ( 5 ) , 7460-82-4; (6), 62726-46-9; ( 7 ) , 62698-60-6
[I]
Phase-Transfer-Catalyzed Reactions, Part 6.-Part 5: A . Merz, R . Tomahogh, Chem. Ber. 101, 96 (1977).
A. M e r z , R . Tomahogh, to be published.
E. i! Dehmlow, Angew. Cbem. 86, 187 (1974); Angew. Chem. Int. Ed.
Engl. 13, 170 (1974); M . Mpkosza, Pure Appl. Chem. 43, 439 (1975).
A. Merz, Angew. Chem. 85, 868 (1973); Angew. Chem. Int. Ed. Engl.
12, 846 (1973).
The reaction also proceeds-but more slowly-without the addition
of tetra-n-butylammonium bromide; the "template effect'' 181 postulated
for the synthesis of crown ethers still has to be reconciled with the
mechanistic concepts of phase-transfer catalysis [3]. In homogeneous
solution ( N a O H in dimethyl sulfoxide) the yield of (6) is much lower
C . J . Pedersen, J. Am. Chem. Soc. 89, 7017 (1967).
C . J . Pedersen, H . K . Frensdorff, Angew. Chem. 84, 16 (1972); Angew.
Chem. Int. Ed. Engl. 11, 16 (1972).
G . W Gokel, H . D. Durst, Synthesis 1976, 168.
D. 3. Cram et aL, Pure Appl. Chem. 43, 327 (1975).
[2]
[3]
[4]
[5]
[6]
[7]
[S]
[9]
is isoelectronic to the metallocenes [Fe(C5H5)'],
[ C O ( C ~ H ~ and
) ~ ][Ni(C5H5)2]2Q[61,
~,
is derived from the paramagnetic, 20-electron sandwich compound nickelocene by
replacement of two CH groups by BR groups and from the
d iamagnetic q -cyclopropeny1 complex [Ni(C H 5)(CPh 41 '1
by insertion of two BR groups with ring expansion. The
metal center in ( 2 ) is formally NilV (for comparison, see
[Ni(q '-C2B9H1i ) ~ ] ' ~ ] ) .
(rpCyclopentadienyl)(q-1,3,4,5-tetraethyl-2-methyl-l,3diboroleny1)nickel ( 2 )
Nickelocene (0.61 g, 3.23 mmol) and ( I ) (0.60g, 3.16mmol)
are heated to 180°C for 2.5 h under N2. The brownish red
product isolated at 120"C/0.1 torr crystallizes from ether/
methanol at - 10°C as orange-red, hexagonal platelets, m.p.
46°C; yield: 0.26g (26 %).
Received: April 27, 1977 [Z 722 IE]
German version: Angew. Chem. 89, 483 (1977)
CAS Registry numbers:
(Z), 62708-15-0; Ni(CsHs)2, 1271-28-9
q-Cyclopentadienyl(qdiborolenyl)nickelA Diamagnetic Nickelocene Analog"]
By Walter Siebert and Manfred Bochmann"]
1,2,5-Thiadiborolenes react as two-electron acceptors with
metal carbonyls to form double-['] and triple-de~kerc~]
compounds. The structurally related 1,3-diborolene~[~I
( I ) should
likewise form mono- and dinuclear complexes as three-electron
acceptors after elimination of H. We now report the thermal
reaction of ( 1 ) (R = C2H5) with nickelocene, which affords
the diamagnetic species ( 2 ) .
[l] Diborylethylene Compounds as Ligands in Metal Complexes, Part 6.
This work was supported by the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen 1ndustrie.-Part 5: W Siebert, R . Full, 3.
Edwm, K . Kinberger, C . Kriiger, J. Organomet. Chem. 131, 1 (1977).
[2] W Siebert, R. Full, C . Kriiger, Y.-H. Tsay, Z. Naturforsch. B 3 1 , 203
(1976); R. Full, Dissertation, Universitdt Wurzburg 1976.
[3] W Siebert, K. Kinberger, Angew. Chem. 88, 451 (1976); Angew. Chem.
Int. Ed. Engl. 1 5 , 434 (1976); ii! Siebert, 7: Renk, K . Kinberger, M .
Bochmann, C . Kruger, ibid. 88,850 (1976) and I S , 779 (1976); ii! Sieberr,
ii! Rorhermel, ibid. 89, 346 (1977) and 16, 333 (1977), respectively.
[4] P. Binger, Angew. Chem. 80, 288 (1968); Angew. Chem. Int. Ed. Engl.
7, 286 (1 968).
[5] K. Wade, Chem. Br. 11, 177 (1975); references cited therein.
[6] R . 3. Wilson, L . F. Warren Jr., M . F. Hawthorne, J. Am. Chem. SOC.
91, 758 (1969).
[7] M . D. Rausch, R . M . Tuggle, D. L. Weatier, .I.Am. Chem. SOC. YZ,
4981 (1970).
Halogenonitrosylmolybdates-Isolation
Classical Mo' Complex
The spectroscopic and analytical data of the orange-red,
in solution air-sensitive compound ( 2 ) are in accord with
a sandwich structure. Apart from the molecular ion C5H5NiL'
[ L = { ( l ) - H } , R=CzH5] (Ire,=lOO%
relative to 11B258Ni),
the mass spectrum (70 eV) displays inter alia the fragments
{C5H5NiL-C2H5}+ (14), {C5H5NiL-C2H5-C2H4}+ (14),
(LNi-H)+ (25), {NiL-C2H5]+ (16), and C5H5Nif (13).
In the 'H-NMR spectrum [6=3.97 (S, 5), 1.3 (M, 4), 0.70
(S, 3), 0.66 (T, 6), 0.37 (T, 6); in C6D6 relative to external
TMS] only one of the two ABX3multiplets for the magnetically
nonequivalent methylene protons can be recognized since the
CH2 signals of the BC2HSgroup are superposed by the two
triplets and the singlet.-The "B-NMR signal exhibits a
pronounced upfield shift (A6=33.3) on going from free (I)
[6=68.6; in hexane relative to external BF3.0Et2] to complex
(Z), which can be explained only in terms of a pentahapto
bonding of the C3B2 ring.
The electron balance in (2) can be described by assuming
construction of the sandwich from two aromatic rings (Cr,
C3B:-) and the Ni d6 cation. O n viewing (2) as nickelacarbaborane with a nido-C3B2Niskeleton it follows that the bonding
molecular orbitals are to be occupied by 2n+4=16 skeletal
electrons[51[3 x 3 (C), 2 x 2 (B), 3 (Ni)]. Complex ( 2 ) , which
[*] Prof. Dr. W. Siebert, M. Bochmann
Fachbereich Chemie der Universitlt
Lahnberge, D-3550 Marburg 1 (Germany)
468
of the First
By Sabyasachi Sarkar and Achim Miiller[*l
Little is known about classical complexes of the lower oxidation states of molybdenum (Moo, Mo', Mo")['I, and although
the oxidation of [Mo(NO)(CN)~]~has repeatedly been investigated no corresponding Mo' complex could be isolated.
We recently reported salts with the anions [Mo(NO)X4]( 1 ) and [Mo(NO)X5I2- ( 2 ) (X=Cl, Br)['I as mononuclear
coordination compounds with simple ligands where Mo can
be regarded as being in the formal oxidation state II (nitrosyl
group as NO+['], (MNO}4 config~ration[~l).
We have therefore attempted the synthesis of the missing species between
K~[Mo(NO)(CN)S] (formally Moo[']) containing the
[MONO]' group and ( 1 ) as well as (2) with the group
[MoN0I3 in the series141
+
[ MoNOIi
{ I \ I O N O } ~ (e4bg)
-
[ M oNOIZf
(MONO}'(- e4bb)
[ MoN0I3+
MONO)^(-
e4)
in order to systematically study the electron distribution over
the three centers M-N-0.
The Mo'-c~mpound[~]
Cs2[Mo(NO)C14H20] ( 3 ) containing the [MONO]'+ group is isolated as stable green crystals
by a new method for the reduction of nitrosyl
[*I Prof. Dr. A. Miiller, Dr. S. Sarkar p * ]
lnstitut fur Chemie der Universitat
Postfach 500500, D-4600 Dortmund 50 (Germany)
[**I Alexander-von-Humboldt-FoundationFellow.
Angew. Chem. Int. Ed. Engl. 16 (1977) NO. 7
O n addition of methanol (10ml) green crystals of (3) separate
slowly. Yield ca. 50 %.
(Reduction and simultaneous substitution due to the strong
trans-effect of NO). Compound (3) can be reconverted into
(2) by "oxidation" and has been characterized by elemental
analyses, thermogravimetry, magnetic measurements, as well
as by photoelectron spectroscopy (XPS), ESR, VIS, and IR
Received: March 24, 1977 [Z 716 IE]
German version: Angew. Chem. 89,479 (1977)
CAS Registry numbers:
(Z), 61505-69-9; ( 3 ) , 62669-50-5
-
A. G. Sharpe: The Chemistry of Cyano Complexes of the Transition
Metals. Academic Press, London 1976; F . A . Cotton, G. Wilkinson.
Table 1. Characteristic data of the Mo' complex ( 3 )
Magnetism
p r w = 1 . 7 7 ~ e(293K)
Electronic transition [a]
E(b2+e(*NO))%17000cm-'
Advanced Inorganic Chemistry. Wiley-Interscience, New York 1972;
D. L. K e p r r t : The Early Transition Elements. Academic Press, London
1972.
S. Sarkar, A . Miiller, Angew. Chem. 89, 198 (1977); Angew. Chem. Int.
Ed. Engl. 16, 183 (1977).
This notation takes into consideration the strong metal-NO interaction
in such complexes(1essd-electron delocalization into the other Mo-ligand
bonds): {MNO} in the perturbing field of the other ligands; see also
J . H . Eitemark, R . D . Feltham. Coord. Chem. Rev. 13, 339 (1974).
Equivalent formulations (for Clv symmetry).
Designation as Mo' is justified if the d character dominates in e in
the case of the configuration e (xz,yz,~*-NO)~b2(xy)'.
Hitherto the only reduction reactions (maintaining the structure of the
complexes!) known entailed concomitant change of the NO group. Cf.
K . G. Caulton, Cood. Chem. Rev. 14, 317 (1975).
a) R . G . H a y e s , J. Chem. Phys. 4 7 , 1692 (1967): bi 8. A. Goodman,
J. B. Raynor, M. C. R. Syrnons, J. Chem. SOC.A 1968, 1973.
ESR [d]
1 35-1
TG
(31
50"C/vac
-H20
' (CS~[MO(NO)CL])
[a] Reflectance spectrum of the solid. [b] Powder at room temperature.
[c] Solution in hydrochloric acid at room temperature. (The possibility of
a ligand exchange reaction is not excluded), [d] Values for the Mo' species
[MO(NO)(CN)~]'-which exists only in solution are given in brackets [7a];
AghoI= g. - g 3 0(see
~ text).
Table 2. I R spectra (solid state; nujol, KBr) of ( 3 ) [cm-']
(31
(2)
Species
[(ON)MoO/C14)
skeleton
C4"
1676 vs
AI
v(NO)
550 w
579 w
A1
v(MoN)
625 w
608.5 w
E
G(MoNO)
A,
~ ( M o - O H ~ )~(Mo-ODZ)
,
(3)
deuterated
3470 s
3385 s [a]
2591 s
2493 s [a]
1624 vs
1624 vs
1603 s
(1573 sh)
1186 m
550 w [c]
625
r.1
381 vw
zzz
360 sh
[a] Additional very weak bands appear at 3190 and 2364 cm-', respectively. [b] v,(MoC14) is overlapped by v,,(MoCL).
[c] In principle reverse assignments are possible.
spectral studies. The data presented in Tables 1 and 2 confirm
that the new species has C4" symmetry with the ground state
configuration e4b& The electron density in the group
[MONO]"+ is expectedly larger in the reduced species (3)
than in (2). Comparison of the ESR data with those of the
only known Mo'-species in
showed a greater difference lgl-gl,l as well as a greater Agavvalue for (3) (see "]).
A knowledge of the complexes of the series [Mo(NO)]"+,
n = 1-3 should improve our understanding of nitrosyl complexes and especially the coordination complexes of lower
valent molybdenum. Redox and ligand exchange reactions
permit development of a "classical" complex chemistry of
Moo, Mo', and Mo", the various complexes being stabilized
by the NO group.
Formation of Benzocyclobutenone by Gas-Phase
Pyrolysis[**]
By Peter Schiess and Markcts HeitzmannC']
We recently demonstrated the formation of alkenylketenes
by elimination of hydrogen chloride from p,y-unsaturated
acyl chlorides at 400 to 600°C in the gas phase. In turn,
the alkenylketenes are transformed into a,P;y,&unsaturated
aldehydes by an intramolecular 1,5-hydrogen shift['].
We have now found that thermal HCI elimination also
occurs readily with ortho-alkyl-substituted aromatic acyl
chlorides ( 1 )['I. The ortho-quinonoid ketene (2) formulated
["I
Experimental
Toasuspension of(2)( 1g)indilute, oxygen-free hydrochloric
acid (20ml, 3 ~ is) added Mg powder (0.14g) in the cold.
Angew. Chem. I n t . E d . Engl. 16 (1977) No. 7
Prof. Dr. P. Schiess, Dipl.-Chem. M. Heitzmann
Institut fur Organische Chemie der Universitat
St. Johanns-Ring 19, CH-4056 Basel (Switzerland)
[**I This work was supported by the Schweizerischer Nationalfonds (Project
No. 2480075) and by CIBA-GEIGY AG.
469
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