Copper, Thioamide Complexes. Syntheses and Structures of Di-m-chloro-bis[N-(pyridin-2-yl)benzenecarbothioamide-S,N']dicopper(I) and of Bis[N-(pyridin-2-yl)benzenecarbothioamide-S,N']copper(I) Chloride, Complxes Containing Tetrahedrally Coordinated Copper Centres

Abstract

The mononuclear copper(I) complex Cu(PhCSNHC₅H₄N)₂Cl (Cu( pbctaH )₂Cl) and the binuclear copper(I) complex [Cu(PhCSNHC₅H₄N) Cl ]₂ ([Cu( pbctaH ) Cl ]₂) have been prepared from copper(II) chloride and N-(pyridin-2- yl ) benzenecarbothioamide ( pbctaH ) and their structures detertnined by single-crystal X-ray diffraction studies. Cu(PhCSNHC₅H₄)₂Cl crystallizes in the space group C2/c with the parameters a 28.042(3) Ǻ, b 6.385(a) Ǻ, c 14.158(12) Ǻ, β 117.01(1)°. The stereochemistry about the copper is essentially tetrahedral, with coordination occurring through the pyridine nitrogen and the sulfur of the thioamide group, and an NCuS angle of 95.7(1)°. [Cu(PhCSNHC₅H₄N)₂Cl]₂ crystallizes in the space group C2/c with the parameters a 16.538(6) Ǻ, b 9.135(4) Ǻ, c 16.470(6) Ǻ, β 93.925(15)°. The crystal is made up of binuclear chloro -bridged units, the essentially tetrahedral stereochemistry about the copper atoms being completed by coordination from the pyridine nitrogen and the sulfur of the thioamide group, with an NCuS angle of 99.5(1)°. The Cu₂Cl₂ group is non-planar, with the copper atoms 0.133 Ǻ above and the chlorine atoms 0.133 Ǻ below the average plane. Other complexes can be isolated from reactions of excess copper(II) chloride with ligand although their structures have not been characterized. A diamagnetic orange compound and a paramagnetic yellow compound apparently derived from copper(n) oxidation of the thioamide were also obtained. Other products, prepared under more basic conditions, are also described. No stable copper(II) complexes of the parent thioamide could be isolated. Use of a 4-nitro substituted benzenecarbothioamide ligand did, however, produce a bis-chelated copper(II) complex.