Organometallics 2002, 21, 2891-2897
2891
Hyd r oxysilylen e-Br id ged Din u clea r Ir on Com p lexes
[Cp (OC)2F e]2Si(X)OH (X ) H, Cl, OH): Syn th esis,
Str u ctu r a l Ch a r a cter iza tion , a n d Con d en sa tion w ith
Ch lor od im eth ylsila n e
Wolfgang Malisch,*,† Matthias Vo¨gler,† Dirk Schumacher,† and Martin Nieger‡
Institute of Inorganic Chemistry, Universita¨t Wu¨rzburg, Am Hubland, D-97074 Wu¨rzburg,
Germany, and Institute of Inorganic Chemistry, Universita¨t Bonn, Gerhard-Domagk-Strasse 1,
D-53121 Bonn, Germany
Received March 7, 2002
The novel bis(ferrio)silanols [Cp(OC)2Fe]2Si(X)OH [X ) H (2), OH (4), Cl (7)] are obtained
via hydrolysis of [Cp(OC)2Fe]2Si(H)Cl (1) or via oxygenation of the bis(ferrio)hydridosilanes
[Cp(OC)2Fe]2Si(H)X [X ) Cl (1), H (6)] with dimethyldioxirane. Subsequent condensation
reactions with chlorodimethylsilane yield the bis(ferrio)siloxanes [Cp(OC)2Fe]2Si(X)(OSiMe2H)
[X ) H (12), OSiMe2H (13), OH (15)]. In an analogous manner the hetero-bismetalated silanol
[Cp(OC)2Fe][Cp(OC)2(Me3P)W]Si(Me)OH (11) and the disiloxane [Cp(OC)2Fe][Cp(OC)2-
(Me3P)W]Si(Me)(OSiMe2H) (14) have been prepared. The influence of the transition metal
substituents on the chemical and spectroscopic properties of these compounds has been
investigated. The X-ray structure analyses of the bis(ferrio)silanol [Cp(OC)2Fe]2Si(H)OH and
the bis(ferrio)dimethoxysilane [Cp(OC)2Fe]2Si(OCH3)2 (5)sgenerated via methanolysis of [Cp-
(OC)2Fe]2SiCl2 (3)sare presented.
In tr od u ction
examples with stereogenic silicon and transition metal
centers, e.g., Cp(OC)(Ph3P)Fe-Si(Me)(Ph)OH.7
Transition metal substituted compounds of silicon
have drawn great attention in recent years mainly due
to their pivotal role in several important catalytic
conversions, e.g., hydrosilylation of olefins,2 dehydro-
genative coupling of primary and secondary silanes,3 or
the ring-opening metathesis polymerization of cyclic
organodisilanes.4 Consequently, a huge number of com-
pounds containing a metal-silicon bond have been
prepared in the past decades by various synthetic
methods, and special attention has been given to the
effect of transition metal fragments to the reactivity of
the silicon atom.5 Among the most outstanding findings
concerning the “transition metal effect” the significant
stabilization of silanols, -diols, and -triols must be
pointed out,6 which makes them attractive precursors
for the designed buildup of metallo-siloxanes, including
In most cases the introduction of an Si-OH function
into metallo-silanes has been accomplished either by
hydrolysis of Si-halogen moieties or by oxygen insertion
into Si-H bonds using dimethyldioxirane. Whereas
several metallo-silanols LnM-SiR3-n(OH)n and even
metallo-disilanols, e.g., LnM-SiCl2Si(OH)3 or LnM-
Si(OH)2SiH3, have been prepared mainly with transition
metal substituents of the chromium and iron group,8
the knowledge concerning hydroxysilylene-bridged di-
nuclear metal complexes is limited to the iron deriva-
tives [Cp(OC)2Fe]2Si(R)OH (R ) Me, pTol) and Cp2(OC)3-
Fe2Si(Mes)(OH) (Mes ) mesityl).9 The most important
aspect concerning this class of compounds lies mainly
in the cumulative electronic effect of the two transition
metal substituents attached to one Si atom. This effect
(5) (a) Corey, J . Y.; Braddock-Wilking, J . Chem. Rev. 1999, 99, 175-
292. (b) Braunstein, P.; Knorr, M. J . Organomet. Chem. 1995, 500,
21-38. (c) Zybill, C.; Handwerker, H.; Friedrich, H. Adv. Organomet.
Chem. 1994, 36, 229-281. (d) Tilley, T. D. In Transition Metal Silyl
Derivatives; Patai, S., Rappoport, Z., Eds.; Wiley: New York, 1991; p
245. (e) Cundy, C. S.; Kingston, B. M.; Lappert, M. F. Adv. Organomet.
Chem. 1973, 11, 253-330. (f) Schubert, U. Adv. Organomet. Chem.
1990, 30, 151-187. (g) Aylett, B. J . Adv. Inorg. Chem. Radiochem.
1982, 25, 1-133. (h) Malisch, W.; Kuhn, M. Chem. Ber. 1974, 107,
979-995.
(6) (a) Adam, W.; Azzena, U.; Prechtl, F.; Hindahl, K.; Malisch, W.
Chem. Ber. 1992, 125, 1409-1411. (b) Mo¨ller, S.; Fey, O.; Malisch, W.;
Seelbach, W. J Organomet. Chem. 1996, 507, 239-244. (c) Malisch,
W.; Lankat, R.; Fey, O.; Reising, J .; Schmitzer, S. J . Chem. Soc., Chem.
Commun. 1995, 1917. (d) Malisch, W.; Lankat, R.; Schmitzer, S.;
Reising, J . Inorg. Chem. 1995, 34, 5701-5702.
† Universita¨t Wu¨rzburg.
‡ Universita¨t Bonn.
(1) Part 22 of the series Metallo-Silanols and Metallo-Siloxanes. In
addition, Part 50 of the series Synthesis and Reactivity of Silicon
Transition Metal Complexes. For Part 21/49 see: Malisch, W.; Hof-
mann, M.; Nieger, M. Novel Silanols and Siloxanes Substituted with
the Feriomethyl Fragment Cp(OC)2FeCH2. In Organosilicon Chemistry
IV: From Molecules to Materials; Auner, N., Weis, J ., Eds.; Wiley-
VCH: Weinheim, 1999; pp 446-450. Malisch, W.; Vo¨gler, M.; Ka¨b, H.
Organometallics 2002, submitted for publication.
(2) (a) Speier, J . L. Adv. Organomet. Chem. 1979, 407-447. (b)
Ojima, I. In The Chemistry of Organic Silicon Compounds; Patai, S.,
Rappoport, Z., Eds.; Wiley: Chichester, 1989; p 1479. (c) Chalk, A. J .;
Harrod, J . F. J . Am. Chem. Soc. 1965, 87, 16-21.
(3) (a) Yamashita, M.; Tanaka, M. Bull. Chem. Soc. J pn. 1995, 68,
403-419. (b) Tilley, T. D. Acc. Chem. Res. 1993, 26, 22-29. (c) Hengge,
E. In Organosilicon Chemistry; Auner, N., Weis, J ., Eds.; Wiley-VCH:
Weinheim, 1994; p 275.
(4) (a) Uchimaru, Y.; Tanaka, Y.; Tanaka, M. Chem. Lett. 1995, 164.
(b) Recatto, C. A. Aldrichim. Acta 1995, 28, 85-92.
(7) (a) Malisch, W.; Schmitzer, S.; Lankat, R.; Neumayer, M.;
Prechtl, F.; Adam, W. Chem. Ber. 1995, 128, 1251-1255. (b) Malisch,
W.; Neumayer, M.; Fey, O.; Adam, W.; Schuhmann, R. Chem. Ber.
1995, 128, 1257-1260.
(8) Malisch, W.; J ehle, H.; Mo¨ller, S.; Saha-Mo¨ller, C.; Adam, W.
Eur. J . Inorg. Chem. 1998, 1585-1587.
10.1021/om020193u CCC: $22.00 © 2002 American Chemical Society
Publication on Web 06/12/2002