Comprehensive comparison between the reaction of N,N'-cyclohexane-1,2-diylidene-bis(4-methoxybenzoylhydrazide) with mercury(II) and copper(II) ions. Synthesis, structure, and kinetics of complex formation

摘要

Comprehensive comparison between the reaction of N,N'-cyclohexane-1,2-diylidene-bis(4-methoxybenzoylhydrazide) (CHMBH) with HgCl2 and Cu(NO3)(2) center dot 2.5H(2)O salts have been investigated, including the synthesis, structure and kinetic of complex formation. The reactions of CHMBH with HgCl2 or Cu(NO3)(2) center dot 2.5H(2)O at the same synthetic conditions have been shown to produce completely different type of complexes: [Hg(CHMBH)Cl-2] center dot CH3CN (I) and [Cu-3(mu(3)-OH)(CTMB)(3)(NO3)(2)(CH3CN)(2)] center dot 5CH(3)CN center dot H2O (II) (CTMB = cyclohexotriazole-3-(4-methoxybenzamide)). The prepared compounds were characterized using different techniques (NMR, IR, UV-Vis and mass spectroscopies, microelemental analysis, thermogravimetry as well as X-ray powder differection and X-ray single crystal crystallography for I (CIF file CCDC no. 1503398). X-ray crystallography shows that the isolated product of I is a mononuclear complex which contains the [Hg(CHMBH)](2+) core. While, the isolated product of II was a trinuclear Cu(II) cluster [Cu-3(mu(3)-OH)(CTMB)(3)(NO3)(2)(CH3CN)(2)] center dot 5CH(3)CN center dot H2O which contains three differently coordinated copper sites. Kinetic studies on the formation of I have been also investigated and compared with that of II. In case of I, the reaction was so slow and exhibits a first-order dependence on the concentration of metal salt and a first-order dependence on the concentration of CHMBH. While in II, the study shows that the reaction is fast and occurs in three distinct phases.