Synthesis, infrared, and X-ray study of di-µ-thiocyanato-1χN,S′:2χN′,S-bis-[bis(2,2′-bipyridine)di-isothiocyanatobismuth(III)]: a case of eight-co-ordinated bismuth

The synthesis, i.r., and X-ray structural characterization of the complex [Bi(CNS)3(bipy)2]2(bipy = 2,2′-bipyridine) are described. Crystals are triclinic, space group P[1 with combining macron], Z= 2, a= 9.935(1), b= 14.487(4), c= 9.916(2)Å, α= 92.29(2), β= 119.81 (1), γ= 99.71 (1)°R= 0.0315. The complex molecules consist of dimeric units in which bismuth is eight-co-ordinated by seven nitrogens belonging to two bipyridyl molecules and to three thiocyanate groups, the last co-ordination site being provided by a sulphur atom of an adjacent molecule which acts as a bridge connecting two polyhedra forming centrosymmetric dimers. The i.r. ν(CN) frequencies are consistent with µ-N,S and terminally N-bonded thiocyanate groups.