Preparation, characterization, and reactivity of the cyclo-metallosilane octaphenyl-cyclo-[bis(triphenylphosphine)]platinio(II)tetrasilane

Abstract

Treatment of 1,4-dihydridooctaphenyltetrasilane, HzSi4(C6H5)8, with bis(triphenylphosphine)ethyleneplatinum(O), [ (C&)3P]zPtCzH4, affords the first example of a transition metal incorporated into a silicon ring, [ (C,#S)~P]~-Pt[Si(C6Hs)z] $i(C6H5)2. Infrared and ultraviolet spectroscopic examinations are reported and compared with similar data recorded for [ ( C & )~P ]~P~C Z H~, Si4(C6H&, and Sis(C6H5)lo. Attempts at several alternate methods of synthesis are discussed as well as reaction of the cyclo-metallosilane with Brz and Hz.

Chemical Properties of Tetragermaplatinacyclopentane. Insertion of an Alkyne into a Pt–Ge Bond and Silylation Caused by H2SiPh2

“…Schram reported [ À Pt(SiPh 2 SiPh 2 SiPh 2 À SiPh 2 )(PPh 3 ) 2 ] as the first example of a transition metal cyclo-oligosilane complex. 6 Four-and five-membered platinacycles containing Si and Ge atoms [ À Pt{GePh 2 (SiMe 2 ) n À GePh 2 }(PPh 3 ) 2 ] (n = 1, 2) were prepared from the reaction of HGePh 2 (SiMe 2 ) n Ph 2 GeH with [Pt(η 2 -C 2 H 4 )(PPh 3 ) 2 ]. 7 Braddock-Wilking reported preparation of five-membered platinacycles [ À Pt(ER 2 ER 2 ER 2 À ER 2 )-(dppe)] (ER 2 = SiC 12 H 8 or GeC 12 H 8 ) from the reaction of [PtMe 2 (dppe)] with excess sila-and germafluorenes.…”

“…Chemistry of persilylated and pergermylated metallacycles has become significant in recent years. Schram reported [Pt(SiPh 2 SiPh 2 SiPh 2 SiPh 2 )(PPh 3 ) 2 ] as the first example of a transition metal cyclo -oligosilane complex . Four- and five-membered platinacycles containing Si and Ge atoms [t{GePh 2 (SiMe 2 ) n GePh 2 }(PPh 3 ) 2 ] ( n = 1, 2) were prepared from the reaction of HGePh 2 (SiMe 2 ) n Ph 2 GeH with [Pt(η 2 -C 2 H 4 )(PPh 3 ) 2 ] .…”

Four-, Five-, and Six-Membered Silaplatinacycles Obtained from the Reaction of an Arylallene with Pt(SiHPh2)2(PMe3)2

“…2,5-Disila-1-metallacyclopentanes − have attracted attention owing to their unique chemical properties and the important roles they play as an intermediate of transition metal complex catalyzed hydrosilylation and bis-silylation of unsaturated compounds. , Most of these complexes were prepared by the oxidative addition of two Si−H bonds of 1,2-bis(silyl)alkanes, HSiR 2 CH 2 CH 2 SiR 2 H, to low-valent transition metal complexes. On the other hand, the reactions of alkene and alkyne with M(SiX 3 ) 2 (PR 3 ) 2 (M = Pd, Pt; X = Me, Ph, F) lead to the formation of their 1,2-disilylation products, , which are closely related to the mechanism of bis-silylation of alkene, allene, and alkyne catalyzed by transition metal complexes. − A similar reaction of alkene or allene with Pt complexes having diorganosilyl ligands would lead to the formation of 1,2-bis(silyl)alkane or 2,5-disila-1-metallacyclopentane as its double oxidative addition product.…”

Preparation and Thermal Reaction of Tetrastannapalladacyclopentane. Sn−Sn Bond Formation and Cleavage

“…Thus, the Sn-Sn bond-forming reactions 24 occur rapidly to form the five-membered palladacycles in high selectively. Group 10 metallacycles composed of oligosilyl 25 and oligogermyl 26 groups have been suggested as one of possible intermediates for catalytic dehydrocoupling condensation to prepare polysilanes and polygermanes.…”