Cadmium(II) and copper(II) complexes containing benzoate derivatives and 2-aminopyrimidine ligands: Synthesis, crystal structures and antibacterial activity

Abstract

The new Cd(II) and Cu(II) complexes namely [Cd2(2-OHbza)4(apm)4] (1), [Cu2(2-OHbza)4(apm)]n•2(2-OHbza) (2) and [Cu2(2-CH3bza)4(apm)]n (3) (2-OHbza = 2-hydroxybenzoate, 2-CH3bza = 2-methylbenzoate and apm = 2-aminopyrimidine) were successfully prepared by using direct one pot synthesis method. All complexes were characterized by using CHN elemental analysis, FT-IR spectroscopy, powder X-ray diffraction and single crystal X-ray diffraction techniques. Compound 1 crystallized in monoclinic space group P21/c, while compound 2 and 3 crystallized in triclinic space group P-1. The dinuclear compound 1 consists of two seven-coordinated Cd(II) centers which are doubly bridged by 2-OHbza bridging ligands, while the rest two 2-OHbza and two apm are terminal ligand. The crystal structure of compound 1 is stabilized by the intermolecular hydrogen bonding and C-H•••π interaction and π•••π interactions. Compounds 2 and 3 present zigzag one-dimensional chainlike-structure which dimer Cu(II) units are linked by apm ligand. The crystal structure of these compounds is stabilized by π•••π and C-H•••π interactions. The photoluminescence properties of compound 1 has been studied comparing to those of 2-OHbza and apm ligands. The solid state PL emission spectrum of compound 1 shows similar intensity of free apm ligand and shape to free 2-OHbza ligand which present a single broad band centered at λem 525 nm (λex = 325 nm), but blue-shift. For solution PL experiment of compound 1 in various solvents, the results showed that compound 1 is selective PL quenching acetone. Electronic spectra for solid state and solution in different solvents of compounds 2 and 3 present the d-d absorption bands centered in the range of 701 – 794 nm. The highest red shifts of λmax are found for compounds 2 and 3 in DMSO. In addition, the antibacterial activity of all compounds are investigated for S.aureus and E.coil by agar diffusion method. The results show that compound 1 exhibits the activity against S.aureus better than E.coil.