Transition metal complexes with pyrazole-based ligands. XXII. Di-μ-thio­cyanato-bis­[(3,5-dimethyl-1H-pyrazole-1-carboxamidine-κ2N,N′)(thio­cyanato-κN)copper(II)] and a redetermination of bis­(3,5-dimethyl-1H-pyrazole-1-carboxamidine-κ2N,N′)bis­(nitrato-κO)copper(II)

Abstract

The title CuIII complex, [Cu2(NCS)4(C 6H10N4)2], represents the first crystal structure of a polynuclear transition metal complex with the 3,5-dimethyl-1H-pyrazole-1-carboxamidine ligand (HL). It is compared with previously reported crystal structures of metal complexes with the same HL ligand. The molecule contains an eight-membered binuclear Cu2(NCS) 2 ring, which is centrosymmetric and in a chair conformation. The Cu atom has a distorted square-pyramidal geometry with a very elongated Cu-S bond of 2.993 (2) Å. The crystal structure redetermination of the bis(3,5-dimethyl-1H-pyrazole-1-carboxamidine-κ2N,N′) bis(nitrato-κO)copper(II) complex, [Cu(NO3)2(C 6H10N4)2], and analysis of its hydrogen bonds confirm the significance of the NO3 groups in the formation of a three-dimensional hydrogen-bonding network. Both complexes are centrosymmetric, the inversion centre being located at the mid-point of the Cu⋯Cu line in (I) and the Cu atom being located at the inversion centre in (II). © 2005 International Union of Crystallography.