The characterization of both the coordinated and non-coordinated saccharinate ion. The syntheses and crystal structures of aqua(2-formylpyridine thiosemicarbazonato)(saccharinato- N)copper(II) hemihydrate and 2,2′-bipyridyl-(2-formylpyridine thiosemicarbazonato)copper(II) saccharinate dihydrate

Abstract

The preparation of the complex [CuL(sacc)- (H 2O)]·0.5H 2O (HL=2-formylpyridine thiosemicarbazone, Hsacc = saccharin) from the reaction of Na(sacc) with [{CuL(CH 3COO)} 2] is described. The complex [CuL(bpy)](sacc)·2H 2O (bpy = 2,2′- bipyridyl) is obtained if the reaction is carried out in the presence of 2,2′-bipyridyl. The complexes have been characterized by a variety of physicochemical techniques and their crystal and molecular structures determined. Crystals of [CuL(sacc)(H 2O)]·0.5H 2O are monoclinic, space group P2 1/n, with a = 7.465(7), b = 9.245(7), c = 26.209(33) Å, β = 97.18(9)° and Z = 4. Crystals of [CuL(bpy)](sacc)·2H 2O are triclinic, space group P 1 , a = 9.243(1), b = 12.393(1), c = 13.323(1) Å, α = 75.511(5), β = 67.751(5), λ = 73.294(7)° and Z = 2. Both complexes contain five coordinate copper with three donor atoms (NNS) contributed by L, which forms a tricyclic ligating system. For [CuL(sacc)(H 2O)]·0.5H 2O the coordination sphere is completed by a monodentate N-bound saccharinate ion and a more weakly bound water molecule giving a distorted square-pyramidal geometry. For the complex [CuL(bpy)](sacc)-2H 2O the remaining coordination sites are occupied by two N atoms from 2,2′-bipyridyl, resulting in a geometry intermediate between square-pyramidal and trigonal- bipyramidal. The saccharinate ion is a non- coordinated anion.