Organosilyl and organogermyl complexes of platinum(II)

Abstract

The preparation of trimethylsilyl and trimethylgermyl complexes of platinum(1i) of the type trans-(Et,P),Pt(MMe,(CI ( M = Si and Ge) from (Me,M),Hg and cis-(Et,P),PtCI, is described. Several reactions are reported involving both chloride ion replacement (Br-, I-, CN-, NCS-, Ph-, and GePh,-) and cleavage of the Pt-M bond [H,O, PhCiCH, (CH,CI),, and H,]. The hydrogenation a t 1 atmosphere has been studied in some detail, and both the Me,Ge and the Me,Si groups are cleaved in preference to the Ph,Ge group in the complexes trans-(Et,P),Pt(MMe,)(GePh,) Infrared and lH n.m.r. spectroscopy have been used to determine the stereochemistry of these complexes. Platinum-silicon, -phosphorus, and -chlorine stretching frequencies have been assigned. In cis-complexes, e.g., (Et,P),PtPh(GeMe,), a unique long-range coupling between the Me,Ge protons and the trans-,lP nucleus is observed. The mass spectrum of trans-(Et,P),Pt(GeMe,)CI is described.

Synthesis of Bis(η2-alkyne) Trinuclear Zwitterionic Platinum Hydride Complexes by Reaction of [trans-Pt(C6F5)2(C⋮CR)2]2- with the Solvento Species [trans-PtHL2(acetone)]+

“…They exhibit one strong absorption in the 2145−2160 cm -1 range, which can be assigned to the ν(Pt−H) vibrations and which is typical for terminal hydride ligands . The values observed in our complexes are lower than those reported for the chloride precursor trans -[PtHClL 2 ] (2220 cm -1 for L = PPh 3 and 2210 cm -1 for L = PEt 3 ) but higher than those reported for complexes of the type trans -[PtH(C⋮CR)L 2 ] (2015−2050 cm -1 ), suggesting that the alkynyl ligands bound in a π fashion exert a lower trans influence than when they are σ-bonded but higher than the Cl atom.…”

“…This latter atom has not been directly located by this analysis, but its position ( trans to the η 2 -alkyne interaction) can be inferred from the NMR data and from the arrangement of the heavy atoms. The Pt(2)−P distances, 2.274(3) and 2.289(3) Å, fall in the range of distances usually observed in Pt(II) phosphine complexes. 12b-f, The coordination of the alkynyl fragment to Pt(2) causes, as expected, the reduction of the P(1)−Pt(2)−P(2) angle to the value of 165.5(1)° due to the lesser steric demand of the hydride ligand.…”

Dimethyl compounds of platinum(II). 2. Reactions involving carbon, silicon, and germanium halogen bonds

“…A twofold excess of trityl chloride (CPh3Cl) (1.0 mmol) was added to a benzene suspension (15 mL) of PtMe2(bpy) (0.5 mmol). After [1][2] days stirring the reaction mixture had turned yellow and the precipitate was collected on a filter and washed with benzene. Recrystallization from CH2C12 afforded light yellow crystals of PtMe2Cl2(bpy) in 70% yield.…”

Towards a catalytic hydrogenolysis of silicon-silicon bonds: Formation of Si–H bonds from disilanes and H2 at platinum

“…For the formation of 7 and siloxane a hydrolysis of the Pt-Si in 6 is also conceivable. 15 The chloro complexes 6-8 have been described before. 16…”