New thallium(III) chloride complexes with pyridine carboxylic acids: from molecular compounds to supramolecular associations

Abstract

Reactions of TlCl3 with picolinic acid (Hpic), nicotinic acid (Hnic), isonicotinic acid (Hinic) and 3-hydroxy-picolinic acid (H3hpic) afford the isolation of new chlorothallium(III) complexes. The compounds are characterized by IR, Raman and multinuclear NMR (1H,13C,205Tl). The molecular structures of [TlCl2(pic)(Hpic)]·0.5H2O (1), [TlCl2(nic)(Hnic)] (2), [TlCl(inic)2]·0.6C2H5OH (3) and [TlCl(3hpic)2(h3hpic)] (4) are determined by single-crystal X-ray diffraction. A distorted octahedral TlCl2N2O2 core containing the O,N-chelating ligands is achieved in the monomeric complex 1. The coordination polyhedron in compounds 2–4 is pentagonal bipyramidal, i.e. TlCl2NO4 in 2, and TlClN2O4 in 3 and 4, respectively. O,O′,N-Bridging ligands result in a polymer chain for 2 and a three-dimensional polymeric association in 3, while compound 4 is monomeric (O, N-and O,O-chelating ligands).