Interaction of the diphenyldichalcogens, C 6H 5EEC 6H 5 (E = S, Se and Te), with the tetrameric halogenotrimethylplatinums. The formation and characterization of [{PtX(CH 3) 3} 2C 6H 5TeTeC 6H 5] (X = Br and I) and a dynamic nuclear magnetic resonance study of [{PtI(CH 3) 3} 2C 6H 5TeTeC 6H 5

Abstract

Te 2(C 6H 5) 2 undergoes reaction with [{PtX(CH 3) 3} 4] (X = Br, I) in chloroform solution to yield the bimetallic products [{PtX(CH 3) 3} 2{Te 2(C 6H 5) 2}]. These complexes have been characterized by elemental analysis and low temperature multi-element ( 1H, 13C, 125Te, 195Pt) NMR studies. [{PtCl(CH 3) 3} 4] was unreactive towards Te 2(C 6H 5) 2, and similarly Se 2(C 6H 5) 2 and S 2(C 6H 5) 2 failed to bring about the fission of the tetranuclear [{PtX(CH 3) 3} 4] (X = Cl, Br, I) molecule. [{PtI(CH 3) 3} 2{Te 2(C 6H 5) 2}] was found to be fluxional over the temperature range −20 to +65°C, and a dynamic NMR study of the complex revealed two different modes of fluxionality. The lower energy process has been ascribed to the concerted/correlated double inversion of the coordinated tellurium atoms (Δ G‡ = 59.7 ± 0.1 kJ mol −1), and the higher energy fluxion (Δ G‡ = 64.5 ± 0.03 kJ mol −1) is attributed to an intermetallic ligand commutation of the two tellurium atoms between the two platinum atoms, leading to exchange of the three platinum methyl environments.