Transition metal halide salts of 8-methylquinolinium: Synthesis and structures of (8-methylquinolinium)2 MX4·nH2O (M = Cu, Co, Zn; X = Cl, Br; n = 0, 1)

The reactions of metal(II) chlorides and bromides with 8-methylquinoline (8-mequin) in neutral and acidic solutions were investigated. The reaction with ZnCl2, ZnBr2, CoCl2, CoBr2, CuCl2 or CuBr2 with the appropriate HX in water or aqueous ethanol gave complexes of the formula (8-mequin)2MX4 (1, M = Cu, X = Cl; 2, M = Cu, X = Br; 3, M = Co, X = Cl; 4, M = Co, X = Br) or (8-mequin)2ZnX4·nH2O (5, X = Cl, n = 0; 6, X = Br, n = 0; 7, X = Cl, n = 1; 8, X = Br, n = 1). Crystals of 1, 2 and 4–8 suitable for single crystal X-ray diffraction were obtained and the structures reported. Compounds 1 and 2 crystallize in the monoclinic space group C2/c, while 4–8 crystallize in the triclinic space group, P 1 ¯ . Variable temperature magnetic susceptibility data indicate very weak interactions for the copper compounds 1 and 2, while the magnetic behavior of 3 and 4 is dominated by single ion anisotropy, with weaker antiferromagnetic interactions.