NABEL A. NEGM*¹, AHMED F. EL FARARGY², MONA A. YOUSSIF¹, SARA MOHAMED¹, M. MEDHAT SAID³
*Corresponding author
1. Egyptian petroleum research institute Department of Petrochemicals, Ahmed El-Zommer Street, 7th region, Nasr City, Cairo, Egypt
2. Zagazig University, Faculty of Science, Zagazig, Egypt
3. National Research Centre, Giza, Egypt

Abstract

Three cationic Gemini surfactants having different spacer chain length and their metal complexes with Cu2+, and Co2+ were synthesized and characterized using elemental analysis, FTIR and NMR and atomic absorption spectroscopy. Surface activities of the surfactants and their metal complexes were determined using surface and interfacial tension measurements. The evaluation of the Gemini surfactants and their metal complexes as biocides against Gram-positive and Gram-negative bacterial strains was done using inhibition zone diameter measurements. Antibacterial activity assay showed that activity increases by the decrease in spacer chain length of surfactants which was correlated to the surface activity and the metal ions type which form the metal complexes.

INTRODUCTION

The biocidal cationic surfactants have attracted considerable attention for their high antibacterial activity and low toxicity for humans. They have been extensively used as topical anti-infective solutions in ophthalmology (1–3), as disinfectants and biocides in water systems (4), in topical wound (5-6), on cotton (7) and environments (8). Monoquaternary ammonium surfactants normally contain both one hydrophilic (water soluble) group and one hydrophobic (oil soluble) chain. This kind of surfactant is called conventional surfactant and is known to have very good antibacterial activity besides a good surface activity and solubilisation properties, (9-10). Schiff bases have gained importance because of their pharmacological, anti-bacterial, antifungal, anti-cancer, anti-viral and physiological activities (11). They are usually synthesized by condensation of primary amines and active carbonyl groups. In recent years, several new classes of surfactants molecules have emerged and attracted the attention of various industrial and academic research groups (12). One of these classes is the Gemini surfactants, which has two hydrophobic and hydrophi ...