Syntheses and characterization of mononuclear Zn(II), Cd(II) and Hg(II) complexes of 2-[(3,5-dibromo-2-hydroxy-benzylidene)-amino]-2-hydroxymethyl-propane-1,3-diol: Photoluminescence properties and DFT study

Abstract

A new Schiff-base ligand HL ((2-[(3,5-dibromo-2-hydroxy-benzylidene)-amino]-2-hydroxymethyl-propane-1,3-diol)) was obtained by the 1:1 condensation of 1,3-dibromo salicylaldehyde and (tris hydroxy methyl) amino methane. Then three new complexes, [Zn(L)2], [Cd(L)2] and [Hg(L)2], have been prepared by the reaction of zinc(II), cadmium(II) and mercury(II) chlorides with the ligand and characterized by routine physicochemical techniques. Complex 1 has further been characterized by single crystal X-ray structural analyses. The ligands, as well as all three complexes, are highly fluorescent. For the ligand, the emission band is attributed to a π → π∗ transition, whereas for the complexes the emissions may be assigned to ligand-to-metal charge transfers (LMCT). DFT calculation of all the three complexes has also been done.