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Organometal Sulfides as Ligands in Pentacarbonylchromium(0) Complexes.

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Organometal Sulfides as Ligands in
Pentacarbonylchromium(0) Complexes[**I
By H. Schumann, 0. Stelzer, and W. Gick [*I
Organo-germanium, -tin, and -lead sulfides are astonishingly
stable compounds, a fact which is explained in many cases as
a result of the participation of the sulfur's lone pair electrons
in the metal-sulfur bond in terms of (p + d) x-type multiple
bonding [I]. Accordingly, trimethylgermyl- and trimethylstannyl-sulfides ought to exhibit a different complex chemical
behavior from dialkyl- or diaryl-sulfides, which occur in a
number of complexes as a-donors 121. Results of previous
investigations [31 showed that in the reactions of transition
metal carbonyls and organotin sulfides the tin-sulfur bonds
are cleaved; stable complexes with organotin sulfides as
ligands could not be prepared.
We have now been able to synthesize for the first time stable
carbonylchromium(0) complexes with organometal sulfides
as ligands by means of the reaction of bis(trimethy1-germy1)-,
bis(trimethylstanny1)-, phenyltrimethylgermyl-, or phenyltrimethylstannyl sulfide with hexacarbonylchromium under UV
irradiation in tetrahydrofuran (THF) at room temperature [41.
complex partner. Further, there is only a trivial change in the
frequencies of the CrS- and MS-stretching vibrations within
the series. In the case of all four compounds an absorption
band, corresponding to their yellow color, is to be observed
in the region of 250-800 nm which is shifted into the longwave region on going from M = Ge to M = Sn.
From the remarkable stability of ( I ) and (2) it follows that
the blocking of a lone electron pair of the sulfur in organometal sulfides by complex formation does not necessarily lead
to the cleavage of the metal-sulfur bond and that consequently organogermanium- and organotin-sulfides can
occur as a-donors in transition metal complexes in the same
way as do dialkyl- or diary1 sulfides.
Experimental:
12 mmoles of organometal sulfide and 12 mmoles (2.6 g) of
hexacarbonylchromium are dissolved in 50 ml of THF
(previously dried over CaH2) in an irradiation apparatus.
The solution is stirred with a magnetic stirrer and irradiated
with a high pressure mercury vapor lampc41. A slightly
reduced pressure in the gasometer that is used for the
measurement of the CO evolved favors the reaction, which is
complete after a period of 2 h irradiation; the solution turns
orange yellow in color. The solvent is removed under vacuum
and the reaction products (in all cases a pale yellow powder;
yields quantitative) can be recrystallized from pentane at
-40 "C. The products can be further purified by sublimation
at 30-75 "C/lO-S torr.
Received: September 3, 1968
[Z 913 IE]
German version: Angew. Chern. 81,256 (1969)
[*I Doz. Dr. H. Schumann, Dip1.-Chem. 0. Stelzer, and W. Gick
(M = G e , Sn)
The choice of solvent in this reaction is particularly important. If pentane is used as solvent instead of T H F then the
rate of reaction is slowed down considerably; this may be
due, on the one hand, to the difference in solubility of the
hexacarbonylchromium in these solvents and on the other
to the part played by T H F in the course of the reaction151.
Compounds ( I ) and (2) are sensitive to atmospheric oxygen
and to water; they are essentially less stable thermally than
are the corresponding organometal-phosphine complexes [61.
As a result of removal of the degeneracy of the El vibration
under the influence of the asymmetrical ligandsC71, the IR
spectra show four CO-stretching vibrations for the Cr(C0)s
skeleton whose positions are only slightly dependent on the
__
vco
(cm-1)
-
( l b ) , Sn 95
(2a),Ge
45
(2b1, Sn 45
2066
1984
1930
1912
2087
2004
1956
1937
2079
1996
1949
1930
2074
1996
1949
1926
-45
441
vMS
(cm-1)
vMStb1
(crn-1)
h
(nm)
383
360
414
366
420
325
348
366
321
435
E =
E =
895
By H . Schulz and I. Sprung [*I
446
367
314
413
s = 174
-44
451
342
342
417
Angew. Chem. internat. Edit. 1 VoI. 8 (1969)1 No. 4
Synthesis of the (&)-JuvenileHormone of the
Giant Silkworm Moth Hyalophora cecropia L.
816
-46
[a] 5 % solution in CDC13, TMS as external standard.
[bl In the free organometal sulfide.
Institut fur Anorganische Chemie der Universitat
87 Wiirzburg, Rontgenring 11 (Germany)
[**IThis work was supported by the Deutsche Forschungsgemeinschaft and the Fonds der Chemischen Industrie.
111 Cf. E. W. Abel, R. P. Bush, C. R . Jenkins, and T. Zobel,
Trans. Faraday SOC.60, 1214 (1964).
[2] Cf. W. Strohmeier, J. F. Guttenberger, and G. Popp, Chem.
Ber. 98, 2248 (1965).
131 E. W. Abel, A . M . Atkins, B. C . Crosse, and G. V. Hutson,
J. chem. SOC.(London) A 1968,687;E. W. Abel and B. C. Crosse,
J. chem. SOC.(London) A 1966, 1141, 1377; E. W. Abel, B. C.
Crosse, and D . B. Brady, J. Amer. chem. SOC.87, 4397 (1965).
[4] Quartz lamp Q 81, Hanau.
[ 5 ] W. Strohmeier, Angew. Chem. 76,873 (1964);Angew. Chem.
internat. Edit. 3, 730 (1964).
[6]H. Schumann and 0.Stelzer, Angew. Chem. 80, 318 (1968);
Angew. Chem. internat. Edit. 7, 300 (1968).
171 E. 0. Fischer and R . Amman, Angew. Chem. 79, 900 (1967);
Angew. Chem. internat. Edit. 6, 879 (1967); S. 0. Grim, D . A.
Wheatland, and W. McFarfane, J. Amer. chem. SOC.89, 5573
(1967).
D = 1200
The H. cecropia juvenile hormone was identified by Roller
et al. [1,21 as methyl cis-l0,11-epoxy-7-ethyl-3.11-dimethyltrans-2,trans-6-tridecadienoate(7). Since then several syntheses of this insect hormone have been published 13-61.
Corey 141, Johnson 161, and Zurfuh 181 report highly stereospecific reactions, of which the synthesis by Zurfiih et al.
leads only to 6-ethyl-lO-methyl-trans-5,cis-9-dien-2-one
(4).
These very elegant procedures, however, require a very considerable number of steps.
We now describe a new synthesis based on the construction
scheme C4 + c 6 + C5 C2.
+
271
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