A copper(I) complex containing a new structure of the [Cu2I3](-) anion. Reaction of CuI with quinaldic acid and the crystal structure of tris-(2-carboxyquinoline)triiododicopper(I) monohydrate

The reaction between copper(I) iodide dissolved in excess NaI and quinaldic acid (H-Quild) afforded two compounds: tris-(2-carboxy quinoline)triiodoco pper(I) monohydrate (1) and [(H-Quild)(2)H](+)I(-.)2H(2)O (2). Both compoun ds are characterised by elemental analysis, electronic, IR and Raman spectr a. They exhibit charge transfer transitions in the visible region. The crys tal structure of complex I shows that it consists of the polymeric [Cu2I3]( -) anion, three H-Quild molecules in zwitterionic form (two of them are lin ked by a hydrogen bond between the two carboxy groups) and a lattice water molecule. The infinite anionic chain [Cu2I3](-) is composed of a fusion of three kinds of rings: rhombus-likeCu(1)I(2), folded Cu2I2, and Cu4I4 in a t wisted-chair conformation, in which the Cu(1) atom is tetrahedral whereas t he Cu(2) atom is trigonal planar. The thermal decomposition of complex 1 is investigated in nitrogen atmosphere. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.