SYNTHETIC STRATEGY, MAGNETIC AND SPECTROSCOPIC PROPERTIES OF THE TERPYRIDINE COMPLEXES [CU(TERPY)X(H2O)N]Y (X = NCO, NCS OR N3 - N = 0 OR 1- Y = NO3 OR PF6) - CRYSTAL-STRUCTURES OF THE AZIDENITRATE AND AZIDENEXAFLUORO-PHOSPHATE

Eight copper(ii) complexes with 2,2':6',2''-terpyridine (terpy) and ps eudohalide ligands, [Cu(terpy)X-(H2O)n]Y [X = NCO, NCS or N3; n = 0 or 1; Y = NO, or PF6] have been prepared by following a described synthe tic strategy. The crystal structures [Cu(terpy)(N3)(H2O)]x[NO3]x and [ Cu(terpy)(N3)-(H2O)]2[PF6]2 have been determined: monoclinic, space gr oup P2(1)/n, a = 8.849(2), b = 10.343(1), c = 18.168(3) angstrom, beta = 97.71(2)-degrees, Z = 4; triclinic, space group P1BAR, a = 9.0609(6 ), b = 10.2798(8), c = 11.309(1) angstrom, alpha = 105.22(7), beta = 8 6.58(7), gamma = 112.90(6)-degrees, Z = 2. In both complexes [Cu(terpy )(N3)-(H2O)]+ entities are present. For the first compound these form a chain structure, via hydrogen bonding between the co-ordinated water molecule and the nitrate ion. However, the structure of the second co mpound is built from dimeric [Cu2(terpy)2(N3)2(H2O)2]2+ cations in whi ch the copper ions are connected by one-end bridging azide groups and PF6- counter ions. The co-ordination geometry of the copper(ii) ion is square pyramidal and octahedral for the two compounds respectively. T he complexes studied can be grouped into three structural types, withi n each of which the compounds are isostructural. The anhydrous and hyd rated hexafluorophosphates have dimeric structures; however, the nitra te compounds are associated in chains. Magnetic susceptibility measure ments revealed weak magnetic interactions for all of them. The EPR spe ctra show 'half-field' forbidden transitions for all the complexes and even singlet-to-triplet forbidden transitions for the nitrates. From the positions of these last signals the exchange parameters for the ni trate compounds have been determined. The magnetic interactions have b een analysed taking into account several exchange pathways.