Oligomerization of phenylgermanes by catalytic dehydrocoupling

Transition‐Metal‐Catalyzed Dehydrocoupling: A Convenient Route to Bonds between Main‐Group Elements

“…Consequently in 1988, Harrod and coworkers reported that phenylgermane, PhGeH 3 , underwent a reaction with [Cp 2 TiMe 2 ] in a manner analogous to phenylsilane to afford Ge-based oligomers (Scheme 5). [13] However, owing to its greater reactivity, the germane dehydrocoupling reaction occurred much more vigorously than in the case of silanes resulting in considerable cross-linking, yielding an insoluble, three-dimensional gel. Presumably the initially formed linear polymer (PhGeH) n is able to undergo intermolecular dehydrocoupling to form new Ge À Ge bonds that function as cross-links.…”

Homogeneous Catalytic Hydrosilylation of Pyridines

“…[15] Experiments with PhMeSiD 2 and C 5 H 5 N, or PhMeSiH 2 and C 5 D 5 N gave products (entry 1, Table 1) in which H/D exchange was much more extensive at the 2-and 6-positions than at other positions of both the products and unchanged pyridine. Extensive H/D exchange also occurred at the 2-and 6-positions of pyridine when 1 atm of H 2 was applied to a solution containing 10 mol % of [{Cp 2 TiH} 2 ] in C 5 D 5 N. [19] Under 15 atm of H 2 complete exchange occurred at the 2-and 6-positions of the pyridine. These H/D exchange results support the mechanism depicted in Scheme 2, and can be easily rationalized by the reversibility between 3 and 4.…”

“…Typically, the reaction was carried out without solvent with a 2:1 molar ratio of silane to pyridine and 10 mol % of [Cp 2 + (PhMeHSi) n generation of the same two peaks (1690 and 1550 cm À1 ) that were observed by direct metalation of 10 with 1. These were also replaced by the signal corresponding to adduct 8 after the addition of 7.…”

“…A sample of 3, generated from the reaction of [{Cp 2 TiH} 2 ] [19] and pyridine at À 20 o C, decomposes immediately upon warming to ambient temperatures to give 2 and a minor amount of 4 (g 1.9905, which is close to the value of g 1.990 for the analogous complex [Cp 2 Ti(h 2 -N,C-2-MeC 5 H 3 N)]). [15] Experiments with PhMeSiD 2 and C 5 H 5 N, or PhMeSiH 2 and C 5 D 5 N gave products (entry 1, Table 1) in which H/D exchange was much more extensive at the 2-and 6-positions than at other positions of both the products and unchanged pyridine.…”

Organometallic Polymers of Germanium, Tin and Lead

“…of Ph 2 GeH 2 with dimethyltitanocene as catalyst predominantly gave the linear tetramer Ph 2 HGe(Ph 2 Ge) 2 GeHPh 2 64 instead of (Ph 2 Ge) n . Phenylgermane PhGeH 3 was reported to give a polymer under similar reaction conditions, but its structure was not sufficiently determined.…”