Synthesis, structure and magnetic investigations of polycarboxylato-copper(II) complexes

Polynuclear Cu(II) complexes bridged by multicarboxylate compounds (1,4,5,8-naphthalene-tetracarboxylic acid, H4nptc; 2,5-pyridinedicarboxylic acid, 2,5-H2pydc; 1,3,5-benzenetricarboxylic acid, 1,3,5-H3btc; tris(acetato)amine) have been synthesized and characterized by IR and UV–Vis spectroscopic techniques. These compounds include [Cu4(pmedien)4(μ4-nptc)(H2O)4](ClO4)4·2H2O (1), [Cu2(pmedien)2(μ2-2,5-pydc)(H2O)](ClO4)2·H2O (2), [Cu3(DPA)3(1,3,5-btc)(ClO4)3]·H2O (3), [Cu3(DPA)3(HN(CH2COO)3)(H2O)3](ClO4)4·3H2O (4), and [Cu3(pmedien)3(HN(CH2COO)3)(H2O)3](ClO4)4·2H2O (5) where pmedien = N,N,N′,N″,N″-pentamethyldiethylenetriamine and DPA = di(2-pyridymethyl)amine. X-ray single crystal crystallography reveal the tetra- and di-nulear bridging nature of the fully deprotonated acids H4nptc and 2,5-H2pydc in complexes 1 and 2, respectively. Magnetic susceptibilities of complexes 1 and 2 which were measured at variable temperatures showed very weak antiferromagnetic coupling.

A novel series of bridged multicarboxylato-Cu(II) complexes with different nuclearity were synthesized and structurally characterized. X-ray single crystal crystallography reveals tetra- and di-nuclear complexes [Cu4(pmedien)4(μ4-nptc)(H2O)4](ClO4)4·2H2O and [Cu2(pmedien)2(μ2-2,5-pydc)(H2O)](ClO4)2·H2O, respectively. The two complexes exhibit very weak antiferromagnetic coupling.Figure optionsDownload as PowerPoint slide