Synthesis, Characterization, X-Ray Diffraction Studies and Biological Properties of Ni(II) and Pd(II) Complexes of Tetradentate Schiff Bases

Abstract

INTRODUCTIONSchiff bases have an important position in the development of coordination chemistry due to their synthetic accessibility and physico-chemical properties. Transition metal complexes of azomethines have photochemical, catalytic, medicinal and electrochemical applications [1][2][3]. Tetradentate ONNO type Schiff bases have been reported for designing macrocyclic biomolecules that help in understanding biological processes [4,5]. Palladium(II) complexes have been investigated for its catalytic activity [6], photoluminescence properties as well as antitumor, anti-HIV and antimicrobial activities [7].The reactions of tetradentate Schiff bases acquired from salicylaldehyde and diamines are a subject of interest of many authors [8,9] due to the ease of preparation and variable geometries. In the present paper, an attempt has been made to synthesize Ni(II) and Pd(II) complexes of tetradentate Schiff bases and further investigate the structure these complexes by spectral characterization and powder X-ray diffraction studies. EXPERIMENTALAll the chemicals used were of analytical reagent grade purchased from SDFCL Mumbai, India and used as such without further purification. Magnetic susceptibility and electronic spectral data confirm the diamagnetic nature and square planar geometry for the complexes. The powder X-ray diffraction data suggested monoclinic crystal system for these complexes. The ligands and their metal complexes have been screened for antimicrobial activities.

Electronic Impacts on the Solvent-Free Mechanochemical Synthesis of Salophen Ligands in Ball Mill

“…e results revealed that the liquid diamine 4 yielded better than both, whereas solid diamines 2 and 5 yielded similarly (Scheme 2). [13,18,20,33] or LAG [23], or at least one of the reactants is liquid (i.e., reactant functioning as LAG) [32]. Except for Garca et al, who synthesized a Salophen ligand containing bromine from 5-bromosalicylaldehyde and a diamine [1], there are no reports on the neat mechanochemical synthesis of Salophen ligands in solidsolid type syntheses to our knowledge.…”