Organometallic Compounds Containing Redox and Fluorescent Active Moieties: Synthesis, Characterization and Biological Study

Abstract

Sandwich and half-sandwich based molecular derivatives are the most versatile organometallic compounds because of their unique structural property, wide chemical and thermal stabilities, reversible redox behavior and for their exclusive nature of reactivity. In the last two-three decades, ferrocenyl chemistry has evolved tremendously as excellent building block for their use in the field of material science, molecular wires, catalysis, molecular recognition, sensing, electronic communication, bio-conjugates and medicinal chemistry. A large number of studies on functionalization of ferrocene have also suggested that ferrocenyl conjugates with carbon chains, carbocyclic and heterocyclic moieties, amino acids, carbohydrate and biomolecules could tune their electronic, structural and biological properties. Over the years, organometallic frameworks have shown unique properties of induced switching using external stimuli which led to the development of high sensitive fluorescence based molecular switches. As a part of our ongoing interest in using sandwich and half-sandwich organometallic fragments for sensor based application and photo-induced behavior, we focused our study on rhodamine based ferrocenyl and cymantrenyl organometallic moieties and exploit their fluorescence, sensing and imaging properties. We envisioned that the presence of organometallic fragment and rhodamine based photochromic component into a molecular compartment may create a fluorescent single molecule - probe for applications related to sensor and switching type molecular devices. In addition, we have been inspired to synthesize various molecular entities containing sandwich and half sandwich moieties linked to organic chains, fluorescent active groups and bioactive groups to explore and understand their biological, electrochemical and photophysical properties. The thesis with five chapters describes the synthesis and characterization of some novel ferrocene and cymantrene based organometallic systems containing fluorescent active rhodamine fragment with hydrazone, enone and cyanovinyl linkages. The report also describes interesting results on the electrochemical and fluorescence behavior of the compounds for sensor based application. Investigations of cytotoxicity and bio-imaging studies have also been described to understand their use in biological application.