Synthesis, crystal structure, thermal behaviour and magnetic properties ofa novel one-dimensional copper(II) complex containing neutral and deprotonated 3-hydroxypyridine ligands

The compound {[Cu(mu-3-pyO-N,O)(3-pyO)(3-pyOH)(H2O)]. 2 H2O}(n) (3-pyO(-)=p yridin-3-onato anion, C5H4NO-; 3-pyOH=3-hydroxypyridine, C5H5NO), has been prepared, its crystal structure determined and its thermal and magnetic pro perties characterised. The structure is made up of infinite one-dimensional chains running along the b axis of copper(ii) atoms linked by bridging N,O -bidentate pyridin-3-onato ligands with a Cu ... Cu distance of 7.030(2) An gstrom. The copper(ii) atom is in a distorted square-pyramidal environment with the basal plane formed by the nitrogen and the oxygen atoms of two bri dging pyridin-3-onato ligands and the pyridinic nitrogen atoms of two termi nal aromatic ligands in a trans arrangement. The apical position is filled by the oxygen atom from a water molecule. One of the two terminal aromatic ligands is a neutral 3-hydroxypyridine. Polymeric chains are held together by means of a three-dimensional network of O-w-H ... O- and O-H ... O- hydr ogen bonding interactions in which there are channels parallel to the a axi s that host solvated H2O molecules. These water molecules are connected to the polymeric chains by means of hydrogen bonds. In the thermal degradation of the title compound, free and co-ordinated water molecules are released in two overlapping endothermic processes between 40 and 90 degrees C. Magne tic measurements show an antiferromagnetic interaction between the metallic centres with a J (triplet-singlet gap) value of -16.4 cm(-1).