Phosphinobenzyl- and aryl-silanes and their triosmium cluster carbonyl derivatives

Abstract

IV respectively. Reactions of the respective bidentate ligands I, II, 111 and IV with [Os,(CO),,( MeCN),] gave the novel triosmium clusters [Os,(p-H)-(CO),,(L-L)] 1,2,3 and 4 involving cleavage of one Si-H bond. Similar reactions of ligands II and IV with [Os,(p-H),(CO),,] afforded t w o new clusters [Os,(p-H),(CO),(L-L)]5 and 6 respectively. The structures of 1, 2, 4 and 5 have been determined by single-crystal X-ray diffraction techniques. In each case, the ligand assumes a chelating mode across the long edge of the osmium triangle which is also bridged by a hydride. The high-performance liquid chromatographic behaviour of these clusters has also been determined and correlated with the size and nature of the ligands.

Supramolecular Sensing with Phosphonate Cavitands

“…This cluster undergoes addition reactions with, for example, phosphines, to form clusters of formula [Os 3 H 2 (CO) 10 (PR 3 )]. It can also undergo a more complicated addition/SiH bond activation process with the functionalized phosphine HMe 2 SiC 6 H 4 CH 2 PPh 2 to afford [Os 3 H(CO) 8 (Me 2 SiC 6 H 4 CH 2 PPh 2 )] 5. In both reactions the resulting cluster core comprises a triangle in which all the OsOs bond lengths are typical of single bonds.…”

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

“…The majority of the reported studies of reactions of silanes with metal complexes involve tertiary silanes and examples are illustrated in Table . − …”

(Phosphinoalkyl)silanes. 3.1 Poly(o-(diphenylphosphino)benzyl)silanes: Synthesis, Spectroscopic Properties, and Complexation at Platinum or Iridium

“…At about the same time, reactivity of the isomeric (phosphinomethyl)phenyl (Ph 2 PCH 2 C 6 H 4 −) system was investigated and found to yield ( o -((diphenylphosphino)methyl)phenyl)trimethylsilane ( o -Ph 2 PCH 2 C 6 H 4 SiMe 3 ) on quenching with chlorotrimethylsilane. Very recently, by the adoption of the reverse approach to P−C bond formation, treatment of chlorodiphenylphosphine with the (silylmethyl)phenyl Grignard reagents o -(RCH 2 )C 6 H 4 MgBr (R = SiMe 2 H, SiMeH 2 ) was examined by Ang et al For either R, however, it was found that this procedure resulted in formation of an inseparable mixture of two positional isomers, viz the ( o -phosphinobenzyl)silane (Ph 2 PC 6 H 4 CH 2 R) together with the corresponding ( o -(phosphinomethyl)phenyl)silane (Ph 2 PCH 2 C 6 H 4 R). Subsequent addition of these isomeric mixtures to triosmium dodecacarbonyl afforded altogether six novel ( o -phosphinobenzyl)silyl− and ( o −(phosphinomethyl)phenyl)silyl−triosmium carbonyl clusters {Os 3 (μ-H)(CO) 10 (μ-SiR 1 R 2 C 6 H 4 CH 2 PPh 2 ), Os 3 (μ-H)(CO) 10 (μ-SiR 1 R 2 CH 2 C 6 H 4 PPh 2 ), or Os 3 (μ-H) 3 (CO) 8 (μ-SiR 1 R 2 C 6 H 4 CH 2 PPh 2 ) for R 1 = R 2 = Me or R 1 = Me, R 2 = H}, which were separated by preparative thin-layer chromatography and then high-performance liquid chromatography.…”