Unusual “Cation-like” Zirconocene Hydrosilyl Complex. Silylium Ligand or a Nonclassically Bonded Si−H?¹

Abstract

The novel zirconocene complexes [Cp′ 2 Zr(µ-H)(SiHR)] 2 2+ [BR′ n (C 6 F 5 ) 4-n ] 2 2-(Cp′ ) Cp, MeCp, Me 5 Cp; R ) Ph or PhCH 2 ; R′ ) Bu or H) were isolated from silane dehydropolymerization reaction mixtures catalyzed by Cp′ 2 ZrCl 2 /2BuLi/B(C 6 F 5 ) 3 or by [Cp′ 2 Zr(µ-H)H] 2 /2B(C 6 F 5 ) 3 combination catalysts. A total structure analysis of these compounds, performed by multinuclear, multidimensional NMR spectroscopy, shows that each zirconocene fragment bears a positive charge, which is delocalized between the metal center and hydrosilane ligand.

Metal-only Lewis pairs between group 10 metals and Tl(i) or Ag(i): insights into the electronic consequences of Z-type ligand binding

“…Similar behavior was observed by Peters in the trigonal-pyramidal Pt salt [(SiP Ph 3 )Pt]BAr F 4 , 83 (SiP Ph 3 = (2-Ph 2 PC 6 H 4 ) 3 Si) for which the crystal structure shows a molecule of toluene bound in the apical position trans to the silyl group. As silyl ligands can be viewed in certain systems as silylium Lewis acids, 84 the binding of an arene molecule may be a result of Pt-to-Si σ-donation, thereby in effect enhancing the Lewis acidic nature of the Pt complex. In addition, similar phenomena have been observed by Gabbaï for a Hg( ii ) complex 85 and by Berry for a bimetallic Mo 2 system.…”

Reactions of Hydrosilanes with Transition-Metal Complexes: Formation of Stable Transition-Metal Silyl Compounds

“…Table − summarizes the products isolated from reactions of primary silanes, RSiH 3 , with transition-metal complexes. Most investigations with primary silanes involve R = aryl, since the low molecular weight alkyl compounds (R = Me, Et, Pr) are gases at 25 °C and thus require more specialized handling.…”

Dehydrocondensation of organylsilanes giving Si–Si bonds

“…44 e. Catalysis by the ternary Cp 2 MCl 2 ± RLi ± B(C 6 F 5 ) 3 system and by the cationic bis(cyclopentadienyl) complexes of zirconium and hafnium Dehydrocondensation of phenylsilanes in the presence of the ternary Cp 2 MCl 2 (CpCp*MCl 2 ) ± 2 BuLi ± B(C 6 F 5 ) 3 catalytic system (M = Ti, Zr or Hf) afforded polyphenylsilanes with M = 10 910 ± 13 790. 47,95,96 It is remarkable that when the reaction was performed in the presence of only B(C 6 F 5 ) 3 at 20 8C for 10 days, the molecular weight of the resulting polyphenylsilane reached only 2450. In both cases, the ratio between linear and cyclic polymers remained the same.…”