名称:
Mononuclear and polynuclear halide and nitrate Cu(II) compounds with 1,4,5-triazanaphthalene as a ligand: Characterization, magnetism and X-ray structures
摘要:
Using the ligand 1,4,5-triazanaphthalene (abbreviated as tan) in combination with Cu(II) salts, three mononuclear compounds, Cu(tan)(2)Cl-2 (1), Cu(tan)(2)Br-2 (3), Cu(tan)(2)(NO3)(2) (5) and three polynuclear compounds, [Cu(tan)Cl-2](n) (2), [Cu(tan)Br-2](n) (4), [Cu(tan)(NO3)(2)](n) (6) have been synthesized and characterized by UV-Vis, EPR, FTIR and Far-FTIR spectroscopies. The crystal structures of compounds 1, 3, 5 and 6 are reported, as well as that of the dioxane adduct of compound 4, [Cu(tan)Br-2(C4H8O2)](C4H8O2) (4A). The structure of (2) was solved by X-ray powder diffraction. The coordination geometry around the Cu (II) atoms is tetrahedral for (1) and (3), square-pyramidal for (4A) and distorted octahedral for (5) and (6). Magnetic susceptibility measurements on the polynuclear compounds revealed weak antiferromagnetic interactions between the Cu(II) atoms with interaction constants (J) of J = -9.1 and -10.5 cm(-1), for 4 and 6, respectively. For compound 2 two options for possible interactions were considered, with interaction constants which vary for J(rung) -22.0 to -13.5 cm(-1) and J(rail) -19.6 to -17.0 cm(-1). These figures are discussed in the light of relevant structural parameters and literature. (C) 2009 Elsevier B.V. All rights reserved.