Template Synthesis and Physicochemical Studies of 14-Membered Functionalized Pendant Arm Schiff-Base Macrocyclic Complexes of Co(II), Ni(II), Cu(II), and Zn(II): DNA Binding Studies on a Cu(II) Complex

A series of functional pendant armed 14-membered Schiff-base macrocyclic complexes [ML(NO3)(2)], where M = Co(II), Ni(II), Cu(II), and Zn(II), has been synthesized by template condensation of 3,3'-diaminobenzidene and acetylacetone. The complexes have been characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, and electrospray ionization (ESI) mass, H-1-nuclear magnetic resonance (NMR), infrared (IR), electronic, and electron paramagnetic resonance (EPR) spectral studies. The results of elemental analyses, ESI mass spectroscopy, and conductivity measurements confirmed the stoichiometry of the complexes, while the characteristic absorption bands and resonance peaks in IR and NMR spectra confirmed the formation of frameworks of complexes. The molar conductance measurements of the complexes in dimethyl sulfoxide (DMSO) correspond to being non-electrolyte in nature. However, the overall geometry of the complexes has been assigned on the positions of bands in electronic spectra and magnetic moment data. The distortion in Cu(II) complexes has been deduced on the basis of EPR data. Absorption and fluorescence studies on the Cu(II) complex show a significant binding to CT DNA.