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Platinum( II ) complexes with ligands (RO) 2 PCH 2 P(OR) 2 (R = Me, Et, Ph, or C 6 H 4 Me-4); crystal structure of cis,cis-[Pt 2 Me 4 {µ-(EtO) 2 PCH 2 P(OEt) 2 } 2 ]

1987; Royal Society of Chemistry; Issue: 9 Linguagem: Inglês

10.1039/dt9870002117

2050-5671

Ljubica Manojlović‐Muir, Ian R. Jobe, Beverley J. Maya, Richard J. Puddephatt,

Inorganic and Organometallic Chemistry

Reaction of the ligands (RO)2PCH2P(OR)2(R = Me, Et, Ph, or C6H4Me-4) with the compounds [Pt2Me4(µ-SMe2)2] or [PtX2(SMe2)2](X = Cl, Br, or I) gives the corresponding complexes cis,cis-[Pt2Me4{µ-(RO)2PCH2P(OR)2}2](1) and cis,cis-[Pt2X4{µ-(RO)2PCH2P(OR)2}2](2). Complexes (2) with R = Me or Et were also prepared by treating [PtX2(SMe2)2] with Cl2PCH2PCl2, followed by reaction with methanol or ethanol respectively. The crystal structure of the complex cis,cis-[Pt2Me4{µ-(EtO)2PCH2P(OEt)2}2] has been determined by X-ray diffraction methods [space group P21/a, a= 28.792(8), b= 10.560(2), c= 11.660(5)Å, β= 99.63(3)°, and Z= 4; R= 0.051 for 3 525 independent reflections with I 2.5σ(I)]. In the molecular structure, two cis-PtMe2 fragments are bridged by two (EtO)2PCH2P(OEt)2 ligands to form an eight-membered Pt2P4C2 ring with Cs boat–chair conformation and a Pt ⋯ Pt separation of 3.459(1)Å. Studies by 1H and 31P n.m.r. spectroscopy indicate that all complexes (1) have this conformation but that complexes (2) adopt a chair conformation. The factors affecting both the formation of mononuclear or binuclear complexes with diphosphinomethane ligands and the conformations adopted by binuclear complexes are interpreted in terms of steric effects of the ligands.