CRYSTAL-STRUCTURE AND MAGNETIC-PROPERTIES OF [(NI-2(DPT)(2)(MU-OX)(MU-N-3))N](PF6)(N) - A NEW STRATEGY TO OBTAIN S=1 ALTERNATING CHAINS

A new alternating magnetic chain with local spin S = 1, with formula [{Ni-2(dpt)(2)(mu-ox)(mu-N-3)}(n)](PF6)(n), in which dpt is the triamine bis-(3-aminopropyl)amine, was synthesized and structurally characterized. The title compound [C14H34N9Ni2O4](n).nPF(6) crystallizes in the monoclinic system, space group P2(1)/a, with fw = 654.87, a = 10.989(1) Angstrom, b = 19.357(2) Angstrom c = 12.598(2) Angstrom, beta = 107.27(1)degrees, Z = 4, R = 0.033, and R(w) = 0.033. Structurally [{Ni-2(dpt)(2)-(mu-ox)(mu-N-3)}(n)](PF6)n can be described as formed by [Ni(dpt)](2+) units linked, alternately, by one oxalato and one azido bridge. A similar compound formuled as [{(Ni-2(Medpt)(2)(mu-ox)(mu-N3)}(n)](ClO4)(n) where Medpt is the triamine methylbis(3-aminopropyl)amine was also synthesized. The susceptibility measurement between 300 and 4 K of [{Ni-2(dpt)(2)(mu-ox)(mu-N-3)}(n)](PF6)(n) indicates an antiferromagnetic behavior with J = -27.4 cm(-1), J' = alpha J = -2.7 cm(-1), alternating parameter alpha = 0.1, g = 2.19.