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)

• Published in: Inorganica Chimica Acta 2011-03, Vol.368 (1), p.141-151
• Main Authors: Edwards, Kimberly, Herringer, Susan N., Parent, Alexander R., Provost, Morgan, Shortsleeves, Kelley C., Turnbull, Mark M., Dawe, Louise N.
• Format: Article
• Language: English
• Subjects: 8-Methylquinolinium; Magnetic susceptibility; Transition metal complexes; X-ray structures
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2010.12.070

A family of transition metal halide complexes with the 8-methylquinolinium geganion, (8-MequinH)2MX4, has been synthesized and studied by single crystal X-ray diffraction and variable temperature magnetic susceptibility. The cobalt complexes exhibit a combination of single ion anisotropy and antiferromagnetic interactions mediated by halide⋯halide contacts. [Display omitted] ► A family of (8-methylquinolinium)tetrahalometallate salts has been prepared. ► The compounds have been characterized via IR, single-crystal X-ray diffraction and, for the Cu and Co salts, variable temperature magnetic susceptibility. ► The Cu salts show weak antiferromagnetic interactions, while the magnetic behavior of the Co salts is dominated by single ion anisotropy. ► The Zn salts may be isolated in both amorphous and monohydrate forms. 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, P1¯. 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.