Thioether functionalized pyrazolate ligands and their dicopper(II) complexes - Structures and magnetic properties

Abstract

A bis(bidentate) compartmental pyrazolate ligand HL with appended methylthiomethyl substituents in the 3- and 5-positions of the heterocycle has been synthesized. It forms doubly pyrazolato bridged dicopper(II) complexes [L2Cu2]X-2 (X = NO3-(3a), ClO4- (3b)) with the metal ions in square planar {S2N2} environment and additional weak axial interactions with the respective counteranions. Magnetic measurements reveal strong antiferromagnetic Coupling with J = -243 or -231 cm(-1) (H = -2J(.)S(I)S(2)), which is at the upper limit of what has previously been observed for bis(p-pyrazolato)dicopper(II) complexes.