[(Pyridylcarbonyl)pyridyl]triazolopyridines, useful ligands for the construction of polynuclear coordination compounds - Synthesis, crystal structure and magnetic properties of a novel tetranuclear copper(II) cubane

A new tetranuclear cubane CU4O4 complex has been synthesised from assembly of Cull ions and the polydentate ligand (pyridin-2-yl){6-([1,2,3]triazolo[1,5-alpha]pyridin-3-yl)pyridin-2-yl}methanone. Crystallographic analysis indicates that the CU4O4 unit has an S-4 symmetry. The magnetic properties have been analysed using the H = -2(i,j)Sigma J(ij)S(i)S(j) spin Hamilto- man. Two distinct coupling constants, 2J(1,3) = -37.4 cm(-1) and 2J(1,2) = -2.6 cm(-1), obtained from the fitting of the experimental data have been rationalised on the basis of a density functional study of magnetostructural correlations in cubane complexes containing the CU4O4 core.