Zinc(II) and cadmium(II) complexes of Schiff bases derived from amino acids and pyridine-3-carboxaldehyde: synthesis, crystal structures, and fluorescence

Two d10 Schiff-base complexes, Zn2(L1)2(H2O)6 ⋅ SO4 (1) and Cd(L2)2(H2O)4 (2) [HL1 = 3-((pyrid-3-yl)-methylene)aminobenzoic acid; HL2 = 4-((pyrid-3-yl)-methylene)aminobenzoic acid], have been synthesized and structurally characterized by elemental analyses, FT-IR spectra, and thermal studies, as well as single crystal X-ray diffraction. Complex 1 is a dinuclear macrocyclic structure with 22-membered rings and is assembled into a 3-D sandwich supramolecular network motif through H-bonding interactions; 2 is a mononuclear structure and is interlinked through H-bonding and π ··· π stacking contacts to generate another 3-D supramolecular network. Furthermore, fluorescent properties of the two complexes are also reported.