Monomeric, dimeric and 1D chain polymeric copper(ii) complexes of a pyrrole-containing tridentate Schiff-base ligand and its 4-brominated analogue.

The synthesis and characterisation of the Schiff-base ligand, HL(1) [N-(1H-pyrrol-2-ylmethylene)-2-pyridineethanamine; derived from 2-formylpyrrole and 2-(2-aminoethyl)pyridine] and copper(ii) complexes of (L(1))(-) in the form of [Cu(2)(L(1))(2)(micro-X)(2)] (X = Cl(-), ; X = Br(-), ; X = N(3)(-), ; X = NCS(-), ) are reported. Bromination of the beta position on the pyrrole ring of (L(1))(-) was observed in the preparation of the di(micro-bromo)-bridged complex [Cu(2)(L(1))(2)(micro-Br)(2)] (), and the copper(ii) complex of the brominated pyrrole derivative (L(1a))(-), , was also obtained. Procedures to synthesise analytically pure samples of and were developed. X-Ray structure determinations carried out on, and reveal that, and are all doubly-bridged square pyramidal copper(ii) dimers [Cu(2)(L(1))(2)(micro-X)(2)] while is an unusual mono(micro-bromo)-bridged square pyramidal copper(ii) 1D chain polymer of the brominated ligand (L(1a))(-), Cu(L(1a))(micro-Br). In the case of [Cu(2)(L(1))(2)(micro-N(3))(2)] () the structure determination reveals that the azide groups bridge the two copper(ii) ions in a 1,1-N(3), end-on, fashion. Variable temperature magnetic susceptibility measurements carried out on the structurally characterised dimeric and polymeric copper(ii) complexes, and revealed weak antiferromagnetic exchange.