Synthesis and characterization of bis(η2-alkyne)dihalogeno-mercury(II) compounds: crystal structure of [NBu4]2-[{cis-Pt(C6F5)2(CCSiMe3)2}HgBr2]·CH2Cl2

Abstract

The reactions of [NBu₄]₂[cis-Pt(C₆F₅)₂(CCR)₂](R = Bu^t or SiMe₃) with HgX₂(X = Cl, Br or I) in a 1:1 molar ratio afforded the simple monomeric bis(η²-alkyne)mercury(II) compounds [NBu₄]₂[{cis-Pt(C₆F₅)₂(CCR)₂}HgX₂](R = Bu^t or SiMe₃; X = Cl, Br or I) in which both alkyne units are co-ordinated η² side-on to the precursor mercury(II) halides. Similar treatment of [NBu₄]₂[Pt(CCR)₄]·2H₂O (R = Bu^t or SiMe₃) with HgX₂ in a 1:2 molar ratio gave the corresponding trinuclear 1:2 adducts. All the complexes have been characterized by analytical and spectroscopic data and, in addition, the molecular structure of [NBu₄]₂[{cis-Pt(C₆F₅)₂(CCSiMe₃)₂}HgBr₂]·CH₂Cl₂ has been determined by X-ray diffraction methods. The structure of the anion shows that the HgBr₂ unit is attached to the dianionic fragment [Pt(C₆F₅)₂(CCSiMe₃)₂]^2– only through η² side-on co-ordination of the two (trimethylsilyl)ethynyl ligands. The platinum–mercury distance is 3.627(1.5)Å.