Synthesis, Characterization, Fluorescence and Antibacterial Activities Studies of Transition Metals Complexes with a Macro Acyclic Schiff Base Ligand

Abstract

The reactions of the Schiff base 2,2’-[(2-hydroxypropane-1,3-diyl) bis-(imino-methane diyl)] bis-(4-bromophenol) (H3L), with metal transition ions (Mn(II), Ni(II), Cu(II), Zn(II), and Cd(II),) afforded one type of complex formulated as [M(HL)(H2O)2].nH2O. These compounds have been characterized by elemental analysis, UV–Vis, FTIR, 1H and 13C NMR spectroscopies, molar conductivity and room temperature magnetic measurements. The structure of nickel (II) complex has been determined by X-ray crystallography. The complex crystallizes in the orthorhombic space group Pnma with a = 7.7702(4) Å, b = 23.1921(15) Å, c = 10.6853(5) Å, V = 1925.57(15) Å3, Z = 8, R1 = 0.043 and wR2 = 0.107, Dcalc = 1.893 Mg m−3. The ligand acts in tetradentate fashion in its di-deprotonated form. Two coordinated water molecules complete the coordination sphere. The environment around the Ni(II) center is best described as an octahedral geometry. In the crystal structure of the Schiff base ligand, the existence of a strong intramolecular O-H•••O hydrogen bonding [O2W-H2W 0.80(3) Å, H2W •••O1 1.915(3) Å, O2W••• O1 2.6258(19) Å, O2W-H2W•••O1 148(3)°] and [O1W-H1W 0.73(3), H1W•••O1 2.15(4) Å, O1W•••O1 2.836(2)Å, O1W-H1W•••O1 156(4)°] are observed. Antibacterial activity study shows that the cadmium (II) complex is more active than the free ligand on.