Synthesis, characterization and antibacterial activities of nickel(II) and copper(II) complexes of an N-pendent cyanoethyl derivative of a tetraazamacrocycle

Cadmium(II) compounds of the bis-cyanoethyl derivative (LCX) of Me8[14]aneC (LC): Characterization and antibacterial studies

The isomeric ligand L_C, a saturated analogue of 2,9-C-meso-Me₈[14]diene, on reflux with excess acrylonitrile afforded 1,8-N-pendant cyanoethyl derivative L_CX. Interaction of L_CX with cadmium(II) perchlorate, nitrate, acetate, and chloride salts produced six coordinated octahedral compounds, [Cd(L_CX) (ClO₄)₂]∙2H₂O, [Cd(L_CX) (NO₃)₂], [Cd(L_CX) (CH₃COO)₂], and [Cd(L_CX)Cl₂], respectively. Further, axial substitution reactions between [Cd(L_CX) (ClO₄)₂]∙2H₂O and KI, KBr, KCl, KSCN, and NaNO₂ in a 1:2 ratio yielded six coordinated octahedral compounds, [Cd(L_CX)I₂]∙H₂O, [Cd(L_CX)Br₂]∙2H₂O, [Cd(L_CX)Cl(ClO₄)]∙2H₂O, [Cd(L_CX) (NCS)₂]∙H₂O, and [Cd(L_CX) (NO₂) (ClO₄)]∙2H₂O, respectively. All of the newly prepared compounds have been characterized by analytical, spectroscopic, molar conductivity, and magnetochemical data. The crystal structure of the ligand L_CX was determined by x-ray crystallography which showed the 14-membered ring to adopt an extended chair conformation. Antibacterial activities of the newly formed cadmium(II) complexes against selected bacteria showed these to exhibit moderate and selective activity with 1-4 and 8 exhibiting greatest potency against the gram negative bacterium Salmonella typhi, and 5, 6, and 7 against the gram positive bacterium Bacillus wiedmannii.