Reaction of low-valent metal complexes with fluorocarbons. Part 30. Bis(cyclo-octa-1,5-diene)platinum with hexafluoroacetone, 1,1 -dicyano-2,2- bis(trifluoromethyl)ethylene and N-methylhexafluoroisopropylideneamine; crystal and molecular structures of [Pt2{(CF3)2CO}(1,5-C8H12)2] and [Pt·C(CF3)2·O·C(CF3)2O·(1,5-C8H12)]

Abstract

Reaction of [Pt(1,5-C₈H₁₂)₂] with hexafluoroacetone affords, depending on reaction conditions, the complexes [Pt₂{(CF₃)₂CO}(1,5-C₈H₁₂)₂], [P[graphic omitted](1,5-C₈H₁₂)], and [P[graphic omitted]H- 1,5-C₈H₁₂)] and [P[graphic omitted](1.5-C₈H₁₂)]. The structural identities of the first two complexes have been established by the analysis of single-crystal X-ray data. The dinuclear complex is monoclinic, space group P2₁/c with four molecules in a unit cell of dimensions a= 9.917(3), b= 14.957(6). c= 13.358(3)Å; β= 102.18(2)°. The structure has been solved by conventional heavy-atom methods from 2 083 diffracted intensities and refined to R 0.038 (R′ 0.044). The molecule contains an approximate mirror plane formed by the two platinum atoms [Pt–Pt 2.585(1)Å] and the carbon and oxygen atoms of the hexafluoroacetone molecule, with the cyclo-octa-1,5- diene molecules symmetrically bonded to each platinum atom in the tub configuration.

Crystals of the second complex are triclinic, space group P with two molecules in a unit cell of dimensions a= 8.212(3), b= 9.329(2), c= 12.610(3)Å: α= 91.87(2). β= 102.10(2). γ= 111.25(3)°. The structure has been solved from 2 659 diffracted intensities to R 0.029 (R′ 0.035) by conventional methods. The platinum atom forms part of a five-membered condensed (head-to-tail) ring P[graphic omitted], and is co-ordinated by a cyclo-octa- 1,5-diene molecule in a tub configuration. In both compounds the platinum atoms show essentially square-planar co-ordination.

In a third complex the hexafluoroacetone forms part of a five-membered ring, in which it links the platinum and an olefin carbon atom of cycle-octa-1,5-diene. A similar complex, [P[graphic omitted]H(1,5-C₈H₁₂)], is a minor product from the reaction of [Pt(1,5-C₈H₁₂)₂] with 1,1 -dicyano-2,2-bis(trifluroromethyl)ethylene. N-Methylhexafluoroisopropylideneamine and [Pt(1,5-C₈H₁₂)₂] afford [P[graphic omitted]Me(1,5-C₈H₁₂)].