Structure effects in copper coordination compounds of ligands with thioether, aromatic nitrogen, and ether donors

Abstract

Preparations of the ligands 1,9-bis(2-pyridyl)-2,5,8-trithianonane (L1) and 1,9-bis(2-pyridyl)-5-oxa-2,8-dithianonane (L2) and their copper(II) complex cations [Cu(L1)]2+ and [Cu(L2)]2+ as ClO4−, CF3SO3−, or BF4− salts are described. X-ray structures of both complex cations as perchlorates are reported. For [Cu(L1)](ClO4)2: space group Pbca, a = 10.4896(5), b = 12.9376(6), c = 33.3943(13) Å, Z = 8, Rf = 0.067, Rw = 0.074 for 1769 reflections. For [Cu(L2)](ClO4)2: space group P21/c, a = 14.388(2), b = 9.990(5), c = 16.076(3) Å, β = 107.919(12)°, Z = 4, Rf = 0.069, Rw = 0.089 for 2813 reflections. Both are slightly distorted square pyramidal species having interactions in the solids between their ClO4− anions and one of the pyridine rings in the L1 complex and the copper atom in the L2 complex. The complexes have been examined by electron spin resonance, electronic spectroscopy, and cyclic voltammetry. The effects of anion coordination, solvation, and removal or alteration of the apical donor atom are assessed by comparisons involving the new complexes and published data on related substances.