A 13C NMR study of several perphenylated polysilanes and cyclo-1,1-bis(h5-cyclopentadienyl)titana-2,2,3,3,4,4,5,5-octaphenylpentasilane

Group 4 Metal and Lanthanide Complexes in the Oxidation State +3 with Tris(trimethylsilyl)silyl Ligands

“…16−19 While in the initial papers by Harrod and co-workers 20−23 on the dehydrocoupling polymerization of hydrosilanes titanium was acting as the catalytically active element, Tilley's mechanistic studies were carried out using hafnium or zirconium. Starting out from CpCp*M(Cl)Si(SiMe 3 ) 3 (M = Zr, Hf) it was shown that σ-bond metathesis reaction with a hydrosilane leads to (Me 3 Si) 3 SiH and a new metal silyl complex, which in reaction with another hydrosilane forms a disilane and a metal hydride. 18 We were curious whether the same chemistry would also work for titanium but quickly realized that CpCp*Ti(Cl)Si-(SiMe 3 ) 3 or even Cp 2 Ti(Cl)Si(SiMe 3 ) 3 is not easily available.…”

“…However, upon crystallization of the reaction mixture an NMR-silent silylated titanium(III) species was detected using single crystal XRD analysis. 24 Subsequent studies revealed that silylated titanocenes with Ti(IV) tend to undergo reductive elimination to "Cp 2 Ti(II)", which in a subsequent comproportionation with Cp 2 TiCl 2 gives Cp 2 TiCl or its respective KCl adduct K[Cp 2 TiCl 2 ] which in a final step can react with (Me 3 Si) 3 SiK to K[Cp 2 Ti(Cl)Si(SiMe 3 ) 3 ]. 25 In order to study the chemistry of silylated Cp 2 Ti(III) complexes, we reacted α,ω-oligosilanyldiides with (18-crown-6)•K[Cp 2 TiCl 2 ] or (tmeda)•Li-[Cp 2 TiCl 2 ] to titanacyclosilanes with titanium in the oxidation state +3.…”

“…25 Further investigations revealed that analogous metallacyclosilanes could be obtained also with Zr(III) and Hf(III). 25 In the current paper we wish to report on reactions of (Me 3 Si) 3 Examples of compounds with lanthanide−silicon (Ln−Si) bonds are still scarce. Among all 4f-elements, samarium and the late lanthanide metals ytterbium and lutetium are best investigated for this class of compounds.…”

“…Investigations on the chemistry of group 4 silyl complexes were started in the late 1960s, with some work on silyl titanium chemistry − and Lappert’s contributions of zirconocene and hafnocene complexes. − Systematic studies of zirconocene and hafnocene silyl complexes were carried out by Tilley and co-workers, − who especially studied aspects of σ-bond metathesis and the catalytic dehydrocoupling polymerization of hydrosilanes catalyzed by these compounds. − While in the initial papers by Harrod and co-workers − on the dehydrocoupling polymerization of hydrosilanes titanium was acting as the catalytically active element, Tilley’s mechanistic studies were carried out using hafnium or zirconium. Starting out from CpCp*M­(Cl)­Si­(SiMe 3 ) 3 (M = Zr, Hf) it was shown that σ-bond metathesis reaction with a hydrosilane leads to (Me 3 Si) 3 SiH and a new metal silyl complex, which in reaction with another hydrosilane forms a disilane and a metal hydride …”

Synthesis of Oligosilanyl Compounds of Group 4 Metallocenes with the Oxidation State +3

“…Among these compounds Cp 2 Ti­(Cl)­SiMe 3 ( I ), prepared by Rösch et al utilizing the reaction of Cp 2 TiCl 2 with Al­(SiMe 3 ) 3 ·Et 2 O, is well characterized with 1 H and 13 C NMR and IR spectra and a low-quality crystal structure ( R = 16%). The titanacyclosilanes Cp 2 Ti­(SiPh 2 ) n ( n = 4 ( II ), 5 ( III )) − were reported as products of the reaction of Cp 2 TiCl 2 with Li­(Ph 2 Si) n Li. While for Cp 2 Ti­(SiPh 2 ) 4 , 1 H and 13 C NMR spectra in acetone were reported, the formation of Cp 2 Ti­(SiPh 2 ) 5 , was substantiated by multinuclear (including 29 Si) NMR and a crystal structure analysis .…”