Structural and Magnetic Behavior of the Kinked Chain Cu(hfac)2(tan) and Its Relevance to Cu(NO3)2(tan) (hfac = Hexafluoroacetylacetonate; tan = 1,4,5-Triazanaphthalene)

When stoichiometric amounts of Cu(hfac)2.H2O) and 1,4,5-triazanaphthalene (tan) were combined in methanol, green crystals of Cu(hfac)2(tan) were formed. Its structure was determined at low temperature (P21/c; a = 8.3308(4) A, b = 14.8945(7) A, c = 18.3046(10) A, beta = 99.298(2)°, V = 2241.5(3) A^3) and found to consist of a novel kinked-chain arrangement where N atoms on opposite sides of the tan ligand bridge Cu(hfac)2 moieties together. Long axial Cu-N bonds lead to rather weak (J!k(B) = -0.06(5) K) antiferromagnetic interactions according to a Bonner-Fisher fit of the magnetic susceptibility data. The magnetic behavior demonstrated by Cu(hfac)2(tan) contrasts markedly with that of Cu(NC)3)2(tan), as reported by Hatfield and co-workers, and is attributed to the differing orientations of the Cu dx^2-gamma^2 magnetic orbital.