Syntheses, electrolytic behaviour and antifungal activities of Zn(II) complexes of isomers of 3,10-C-meso-3,5,7,7,10,12,14,14-octamethyl-1,4,8,11- tetraazacyclotetradecane (L). Crystal and molecular structure of [ZnL B(NO3)]NO3 (LB = a,e,a,e-L)
The isomeric cyclam ligands Me-8{[}14]anes, designated by L-A, L-B and L-C, produce, on reaction with zinc(II)-nitrate, zinc(II) sulphate or zinc(II) chloride corresponding complexes, i.e. dinitrato/mononitrato-nitrate complexes {[}ZnL(NO3)(2)]/{[}ZnL(NO3)](NO3) (L = L-A, L-B or L-C, where the indices A, B and C refer to differing orientations of the four methyl groups on secondary carbons of Me-8{[}14]ane), the diaqua-sulphates {[}ZnL(H2O)(2)]SO4 (L = L-A, L-B or L-C), and the diaqua dichloride and dichlorido complexes {[}ZnL(H2O)(2)]Cl-2 (L = L-A or L-C) or {[}ZnLBCl2], respectively. The complexes have been characterised on the basis of elemental analyses, IR, UV-Vis, H-1 and C-13 NMR spectroscopies, magnetic and conductance data. The structure of {[}ZnLB(NO3)](NO3) has been determined by X-ray crystallography. The zinc centre is coordinated to a N4O donor set in a square-pyramidal geometry. The complexes show differing electrolytic behaviour in different solvents. In chloroform, the complexes are non-electrolytes, indicating that both anions are coordinated to Zn2+. Antifungal activity of the ligands and complexes against the phytopathogenic fungi Alternaria alternata and Colletotrichum corcolei have been investigated, and positive results were noted. (C) 2011 Elsevier B. V. All rights reserved.