Two New Side-chain Tripod Structure Containing Imidazole Ligands And Their Transition Metal Complexes, Synthesis And Characterization

Two novel models of heptadentate tripodal ligands containing imidazoles (MIM)₃t-ren = tris{2-[2-(1-methyl)imidazolyl]methyliminoethyl}amine, (MIM)₃Htren = tris{2-[2-(1-methyl)imidazolyl]methylaminoethyl}amine and corresponding transition metal complexes: [Cu(MIM)₃tren](ClO₄)₂·3CH₃CN (1), [Fe(MIM)₃tren](ClO₄)₂·CH₃CN (2), [Co(MIM)₃tren](ClO₄)₂ (3), [Ni(MIM)₃tren](ClO₄)₂ (4), [Fe(MIM)₃Htren](ClO₄)₂ (5), [Fe(MIM)₃Htren](ClO₄)₃(6), {Cu₃[(MIM)₃Htren]₂}(ClO₄)₆·2H₂O (7), {Cu₃[(MIM)₃-Htren]₂}(PF₆)₆·2(CH₃CN)·2H2O (8) were synthesized. The ligands and complexes are characterized by elemental analysis, infrared spectroscopy, Uv-vis spectroscopy, Mossbauer spectroscopy at room temperature and variable temperature susceptibility. The crystal analysis results show that the complexs 1 4 are all mononuclear complexes, in which each metal atom is coordinated in a octahedral geometry of [MN₆]. The clelate N atoms come from three imine N atoms of three arms from (MIM)₃tren and three N atoms from imidazole, respectively; and three imine N atoms and the N atoms of imadazloes form two parallels, and in which the site symmetry of each cation for the four complexes is close to C₃ with the pseudo-C₃ axis passing through the metal atom and tripodal nitrogen atom.For the complexs 5-8, (MIM)₃Htren presents various chalate fashions. The results of the crystal structures show 5 is also coordinated in a octahedral geometry of [MN₆] the same as that of the complexs 1 4 , in which the site symmetry of each cation for the four complexes is close to C₃ with the pseudo-C₃ axis passing through the metal atom and tripodal nitrogen atom. The (MIM)₃Htren in the complex 6 exhibits heptadentate chelate function which make the Fe(III) atom coordinate in a monocapped anti-trigonal prism of [MN₇], in which the site symmetry of each cation has an exact C₃ site symmetry since a crystallographic C₃ axis passes through the metal atom and tripodal nitrogen atom.The complexes 7 and 8 are both trinuclear complexes, in the trinuclear cation, one Cu(II) atom, locates on a crystallographic inversion centre, adopts plane-square geometry, and the other two Cu(II) atoms are coordinated by N5 in the basal positions...