Two new organic-inorganic complexes associating the radical anion ABTS(-) and the inorganic cation Ca2+: Ca-0.55(ABTS)(H2O)(x) and Ca-5(ABTS)(6)(H2O)(29)

The synthesis, crystal structure determination and physical properties of t wo new charge transfer salts containing the azinobisethylbenzothiazoline (A BTS) anion are described. Electrochemical oxidation in water of the diammon ium salt of ABTS in presence of calcium chloride yields black single crysta ls of two new compounds with different morphologies. The needle-like crysta ls with Ca-0.55(ABTS)(H2O)(x), formula (x depending on the temperature) bel ong to the monoclinic symmetry, space group C2/c and cell parameters a = 21 .568(5), b = 14.535(5), c = 8.0278(17) Angstrom, beta = 108.32(3)degrees at room temperature and a = 22.180(4), b = 14.288(3), c = 8.0823(16) Angstrom , beta = 108.13(3)degrees, with a lowering of the symmetry, space group Cc, at 200 K. The plate-shaped crystals formulated as Ca-5(ABTS)(6)(H2O)(29) b elong also to the monoclinic symmetry with P2(1) space group and cell param eters a = 11.222(2), b = 37.991(8), c = 19.327(4) Angstrom, beta = 106.37(3 )degrees at 200 K. The structure analysis of the first phase shows a one-di mensional character based on the stacking of organic molecules creating cha nnels in which Ca2+ cations and water molecules are located. The second pha se can be described as an alternation of organic and inorganic layers corre sponding to a bidimensional hybrid network. The magnetic and electrical pro perties will be discussed. (C) 2001 Editions scientifiques et medicales Els evier SAS. All rights reserved.