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

Abstract

An octamethyl substituted tetraazacylotetradecadiene ligand salt Me8[14]diene.2HClO4 (L.2HClO4) on reduction produced three isomeric C-chiral ligands LA, LB & LC. Interaction of LB with excess acrylonitrile resulted in a N-pendent cyanoethyl derivative ligand, LBX. Reaction of LBX with nickel(II) salt, Ni(CH3COO)2.4H2O followed by the addition of NaClO4 afforded the complex, [NiLB](ClO4)2, as resulted by the interaction with LB instead of LBX with the same nickel(II) salt which on twelve hours reflux with acrylonitrile yielded square planar nickel(II) diperchlorate complex, [NiLBX](ClO4)2, This complex underwent axial addition reactions with KX (X = SCN, Br or I) and NaNO2 to form octahedral diisothiocyanatonickel(II) complex, [NiLBX(NCS)2]; dibromidonickel(II) complex, [NiLBXBr2]; diiodidonickel(II) complex, [NiLBXI2] and monoaquamononitronickel(II) perchlorate complex, [NiLBX(NO2)(H2O)](ClO4) respectively. The ligand, LBX with copper(II) chloride yielded purple dichloridocopper(II) complex, [CuLBXCl2] of octahedral geometry which underwent axial substitution reactions with KX and NaNO2 to form octahedral diisothiocyanatocopper(II) complex [CuLBX(NCS)2]; dibromidocopper(II) complex [CuLBXBr2]; diiodidocopper(II) complex, [CuLBXI2] and dinitrocopper(II) complex [CuLBX(NO2)2] respectively. These complexes were characterized on the basis of elemental, spectroscopic, magnetochemical and conductrometric analysis. The antibacterial activities of the ligand and complexes have been investigated against different human pathogenic gram positive and gram negative bacteria.