Synthesis, characterization, spectroscopy, magnetism and X-ray structures of red and green Cu(II) chloride adducts with bis(2-benzimidazolyl)propane

摘要

Two different Cu(II) compounds, having the same stoichiometry, were obtained with the ligand bis(2-benzimidazolyl)propane (abbreviated as tbz) with the formula [Cu(tbz)Cl_2]. The copper atom in the red isomer (1) has a tetrahedral geometry, while in the polymeric green isomer (2) two different copper sites are present, one perfectly square planar and a second tetragonally distorted square planar. Compound 1 crystallises in the orthorhombic space group Pbca with a = 13.5373(11), b = 15.3002(9), c = 15.9117(7) A, Z = 8. Compound 2 crystallises in the monoclinic space group P2/c with a=12.4964(13), b = 10.3750(15), c = 13.568(2) A, #beta# = 91.643(10) deg, Z = 4. Further characterization was done by ligand field, IR spectroscopy and EPR. Solid-state spectra agree with tetrahedral geometry, and square-planar based geometry. Frozen-solution EPR in DMSO shows a trigonalbipyrimidal geometry with dz~2 groups state.