Synthesis, Crystal Structure, Electronic Spectroscopy, Electrochemistry and Biological Studies of Ferrocene–Carbohydrate Conjugates

Abstract

AbstractA series of six new ferrocene–carbohydrate conjugates was prepared from pentose and hexose sugar derivatives. These include the ferrocenecarbaldehyde acetal 2, four ferrocenyltriazoles 4a–d derived from furanose sugar and the ferrocenyltriazole 4e derived from a pyranose sugar. The compounds were characterised by spectroscopic means and the structures of the new conjugates 2 and 4a were determined by means of X‐ray crystallography. A UV/Vis study of these compounds performed in aqueous solutions under physiological conditions confirmed their stability. The CD spectral analysis shows the effect of the nature of substituents of the carbohydrate moieties. The electrochemical studies conducted in a buffer solution display one‐electron reversible oxidation processes for these compounds. These results indicate that the compounds are suitable for conducting biological studies. The cytotoxicity and antimicrobial activity of these conjugates were investigated on different cancer cell lines and microbes, respectively. These compounds exhibit moderate to good cytotoxicity towards cell lines like A549 (human alveolar adenocarcinoma cells), Neuro2a (mouse neuroblastoma cells), HeLa (cervical carcinoma cancer cells), MDA‐MB‐231 (human breast adenocarcinoma cells) and MCF‐7 (human breast adenocarcinoma cells). The compounds show antibacterial activity against both Gram‐positive and Gram‐negative pathogens. Compound 2 exhibits excellent inhibitory activity against E. coli with a MIC value of 4.8 μg mL–1. In addition, compounds 2 and 4a also exhibit antioxidant activity comparable to the standard antioxidant ascorbic acid.