Copper(II) Complexes With Bis-Schiff Bases: Synthesis, Crystal Structures, and Antibacterial Activities

Abstract

Reaction of copper perchlorate with the tridentate Schiff bases N,N’-bis(5-methoxysalicylidene)-1,2-ethanediamine (H₂L¹) and N,N’-bis(5-chlorosalicylidene)-1,3-propanediamine (H₂L²), afforded a dinuclear complex, [Cu₂(L1)₂]·2CH₃OH (1), and a mononuclear complex, [CuL²] (2). The complexes were characterized by single-crystal X-ray diffraction, FT-IR, and elemental analysis. The Cu atom in complex 1 is in a square pyramidal coordination, with two phenolate O and two imine N atoms of L¹ ligand defining the basal plane, and with one phenolate O atom of another L¹ ligand occupying the apical position. The Cu atom in complex 2 is coordinated by two phenolate O and two imine N atoms of L² ligand, forming a tetrahedrally distorted square planar geometry. The free Schiff bases and the complexes were assayed for antibacterial activities. Both complexes are more active against the bacteria than the free Schiff bases. Complex 2 has the MIC value of 0.10 μg mL⁻¹ against Bacillus subtilis.

Keywords:

• bis-Schiff base
• copper complex
• crystal structure
• antibacterial activity

Supplementary Material

CCDC Numbers 1429415 (1) and 1429344 (2) contain the supplementary crystallographic data for this paper. These data can be obtained free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html or from the Cambridge Crystallographic Data Center, 12, Union Road, Cambridge CB2 1EZ, UK; fax: (internat.) +44-1223/336033; E-mail: [email protected].