Synthesis, crystal and molecular structure and magnetic properties of [Ni3(L1)4(NCS)4(OH)2(OH2)2](L1= 2,5-diamino-1,3,4-thiadiazole)

Abstract

The product of the reaction between nickel(II) thiocyanate and 2,5-diamino-1,3,4-thiadiazole (L¹), [Ni₃(L¹)₄(NCS)₄(OH)₂(OH₂)₂], has been characterized by means of structural, magnetic and spectroscopic measurements. The crystals are monoclinic, space group P2₁/c, with a= 8.132(2), b= 16.551(3), c= 12.495(2)Å. β= 95.52(1)° and Z= 2. The structure was solved by the heavy-atom method, and least-squares refinement of the structural parameters led to a conventional R factor of 0.034 for 1436 observed reflections. The structure consists of centrosymmetric trimeric discrete molecules in which the nickel(II) atoms are co-ordinated in slightly distorted octahedral geometries by two nitrogen atoms of the thiadiazoles, two nitrogen atoms of thiocyanate groups, and by two oxygen atoms. The central nickel atom is linked to each terminal nickel atom by two planar thiadiazole and one oxygen bridging molecule; the nearest-neighbour Ni^II⋯ Ni^II distance is 3.320(4)Å.