Silicon transition-metal complexes

Investigations of silicon-metal systems are of fundamental interest, since stable coordination compounds with low valent silicon are still rare [64], and furthermore, silicon transition-metal complexes have a high potential for technical applications. For instance, coordination compounds of Ti, Zr, and Hf are effective catalysts for the polymerization of silanes to oligomeric chain-silanes. The mechanism of this polymerization reaction has not yet been fully elucidated, but silylene complexes as intermediates have been the subject of discussion. Polysilanes find wide use in important applications, e.g., as preceramics [65-67] or as photoresists [68-83],... 

E. Silicon-Transition Metal Complexes Having Special Structural... 

Silicon-Transition Metal Complexes with Special Structural Features... 

Selected Distances and Angles eor Silicon-Transition Metal Complexes... 

A general review by Cundy et al. (76) on silicon-transition metal complexes has appeared, and again, we select only a few molecules to highlight different properties and chemistry within an isoelectronic group. In the four examples (Cp)Mn(CO)2(/u-H)Si(F)(Ph)2 (30), (Cp)Fe(CO)2Si-(F)(Ph)2 (31), (Cp)Mn(CO)2(M-H)Si(Cl)3 (32), and (Cp)Fe(CO)2Si(Cl)3 (33), compounds 30-31 and 32-33 are isoelectronic pairs based on the total number of valence electrons. Compounds 30 and 32 also form a related pair with respect to the three-center, two-electron Si—H—Mn interactions. 

In spite of the many known silicon-transition metal complexes (15,16), little systematic work has appeared on the reaction mechanisms of silyl metal complexes. This state of affairs is in marked contrast to the current work on cr-alkyl transition metal complexes, where much emphasis is placed on determining detailed decomposition mechanisms (75-76). The reason for the interest in decomposition mechanisms is that the products of a transition metal-catalyzed reaction are released by the decomposition of the product-metal complex. Thus, to understand a catalytic process, one must have knowledge not only of the interaction of the reactants with the metal (leading to a substrate-metal complex), but also of the mechanisms whereby substrates are transformed on the metal and the manner in which the products are released. 

Metallo-Silanols and Metallo-Siloxanes, Part 5. - Part 4 W. Malisch, K. Grun, N. Gunzelmaim, S. Moller, R. Lankat, J. Reising, M. Neumayer, O. Fey, in Selective Reactions of Metal Activated Molecules (Eds. H. Werner, J. Sundermeyer), Vieweg Verlag, Braunschweig, in press in addition Part 30 of the series Synthesis and Reactivity of Silicon Transition Metal Complexes. 

Part 3S of the series Metallo-Silanols and Metalto-Siloxane. In addition, Part 64 of the series Synthesis and Reactivity of Silicon Transition Metal Complexes. Part 63/34, see Ref. [1]. 

Part 16 in the series "Metallo-Silanols and Metallo-Siloxanes". In addition. Part 42 of the series "Synthesis and Reactivity of Silicon Transition Metal Complexes". Part 15/41, see W. Malisch, M. Neumayer, K. Perneker, N. Gunzelmann, K. Roschmann, in Organosilicon Chemistry III From Molecules to Materials (Eds. N. Auner, J. Weis), VCH, Weinheim, 1997, p. 407. 

Part 13 of the series "Metallo-Silanols and Metallo-Siloxanes". In addition. Part 39 of the series "Synthesis and Reactivity of Silicon Transition Metal Complexes". Part 12/38 see Ref [2a]. 

The mechanism and stereochemistry of nucleophilic substitution at silicon, including displacement of silyl ligands in silicon-transition metal complexes. 

Due to their important role as intermediates in the technical synthesis of silicones, organosilanols have been the subject of extensive studies over several decades [2], In context with studies on the reactivity of functionalized silicon-transition metal complexes a new type of silanols containing an Si-bonded transition metal has been established. Access to these metallosilanols is opened by the hydrolysis of metallohalosilanes [3] and by the oxygenation of metallosilanes with dimethyl-dioxirane [4]. Recently also a catalytic pathway for the SiH/SiOH conversion in the case of... 

Reactivity of Silicon Transition Metal Complexes". Part lOtAl, see [1]. 

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