SYNTHESIS AND CHARACTERIZATION OF BIS(ETA(2)-ALKYNE)DIHALOGENO-MERCURY(II) COMPOUNDS - CRYSTAL-STRUCTURE OF [NBU(4)](2)-[(CIS-PT(C6F5)(2)(C-CSIME(3))(2))HGBR2]CENTER-DOT-CH2CL2

The reactions of [NBu(4)](2)[cis-Pt(C6F5)(2)(C=CR)(2)] (R = Bu(1) or SiMe(3)) with HgX(2) (X = Cl, Br or I) in a 1:1 molar ratio afforded the simple monomeric bis(eta(2)-alkyne)mercury(II) compounds [NBu(4)](2)[{cis-Pt(C6F5)(2)(C=CR)(2)}HgX(2)] (R = Bu(1) or SiMe(3); X = Cl, Br or I) in which both alkyne units are co-ordinated eta(2) side-on to the precursor mercury(II) halides. Similar treatment of [NBU4](2)[Pt(C=CR)(4)].2H(2)O (R = Bu(1) or SiMe(3)) with HgX(2) 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 [NBu(4)](2)[{cis-Pt(C6F5)(2)(C=CSiMe(3))(2)}HgBr2].CH2Cl2 has been determined by X-ray diffraction methods. The structure of the anion shows that the HgBr, unit is attached to the dianionic fragment [Pt(C6F5)(2)(C=CSiMe(3))(2)](2-) only through eta(2) side-on co-ordination oi the two (trimethylsilyl)ethynyl ligands. The platinum-mercury distance is 3.627(1.5) Angstrom.