Two Solvent-Controlled Copper(II) Complexes Constructed from Tris[(benzimidazol-2-yl)methyl]amine and m-Phenylenediaminetetraacetic Acid

The reactions of tris[(benzimidazol-2-yl)methyl]amine (ntb) and 1,3-phenylenedinitrilotetraacetic acid (H(4)mpda) with copper nitrate can produce complex 1 from CH3COCH3/CH3OH/H2O and complex 2 from DMF/CH3OH/H2O. Complexes with the formula of [Cu(ntb)(H(2)mpda)]center dot 0.5CH(3)COCH(3)center dot 2H(2)O (1) and [Cu(ntb)(H(2)mpda)]center dot DMF center dot CH3OH center dot 2H(2)O (2) both have [Cu(ntb)(H(2)mpda)] structural units, in which Cu(II) centers always have a five-coordination number bound to one ntb ligand and one H(2)mpda anion. All these complexes possess trigonal bipyramidal coordination geometry. However, metal ions show remarkable differences in structures due to the effects of solvents. Comparing to complex 1, complex 2 possesses more distorted coordination geometry. The positions of ntb and H2mpda ligands in 1 and 2 are very different. The mononuclear coordination units are extended by hydrogen-bonding into different three dimensional networks. CCDC: 893363, 1; 893364, 2.