First-row transition metal–pyridine (py)–sulfate [(py)xM](SO4) complexes (M= Ni, Cu and Zn): crystal field theory in action

Abstract

The crystal structures of three first-row transition metal–pyridine–sulfate complexes, namelycatena-poly[[tetrakis(pyridine-κN)nickel(II)]-μ-sulfato-κ2O:O′], [Ni(SO4)(C5H5N)4]n, (1), di-μ-sulfato-κ4O:O-bis[tris(pyridine-κN)copper(II)], [Cu2(SO4)2(C5H5N)6], (2), andcatena-poly[[tetrakis(pyridine-κN)zinc(II)]-μ-sulfato-κ2O:O′-[bis(pyridine-κN)zinc(II)]-μ-sulfato-κ2O:O′], [Zn2(SO4)2(C5H5N)6]n, (3), are reported. Ni compound (1) displays a polymeric crystal structure, with infinite chains of NiIIatoms adopting an octahedral N4O2coordination environment that involves four pyridine ligands and two bridging sulfate ligands. Cu compound (2) features a dimeric molecular structure, with the CuIIatoms possessing square-pyramidal N3O2coordination environments that contain three pyridine ligands and two bridging sulfate ligands. Zn compound (3) exhibits a polymeric crystal structure of infinite chains, with two alternating zinc coordination environments,i.e.octahedral N4O2coordination involving four pyridine ligands and two bridging sulfate ligands, and tetrahedral N2O2coordination containing two pyridine ligands and two bridging sulfate ligands. The observed coordination environments are consistent with those predicted by crystal field theory.