Synthesis and physicochemical characterizations of 3d transition metal based anisotropic complexes : building block approach for designing multifunctional materials

Includes bibliographical references.

PhD;2024;Solid State and Structural Chemistry Unit.

Molecule-based magnetic materials have been a popular choice in recent times, to generate multifunctional materials1. An inherent property in such systems is molecular bistability which enables a system to interchange between two accessible states through controlled application of external stimuli2. Multifunctional molecular magnetic materials3 have fascinating applications in information storage4, spintronics5, quantum computing6 as well as biomedical applications. A suitable synthetic procedure for such molecular magnetic systems entails a so-called “bottom-up” building block approach, where anisotropic monometallic complexes function as the elementary unit. The molecule-based magnetic materials are known to exhibit several intriguing properties such as Spin Crossover (SCO)7, Single Molecule Magnet (SMM)8, Magnetic sponge, and Linkage Isomerism9 behavior. In my thesis, firstly I have synthesized some macrocyclic porphyrin-based monometallic systems to look for the possibilities of these molecules to function as molecular magnets. Detailed spectroscopic, electrochemical, magnetic, and theoretical studies have been performed on these systems to get a clear idea of their feasibility as a viable multifunctional molecular magnet. Following this, I have explored the molecular magnetic sponge-like behavior in a family of heterobimetallic cyano-bridged [CrMn] coordination networks, where absorption and desorption of solvent molecules plays a crucial role on the magnetic properties. Next, photo- and thermo-induced spin crossover properties have been investigated in a few heterobimetallic cyano-bridged [Cr2Fe3] multifunctional molecular clusters where the linkage isomerism property has been simultaneously observed. In the last part of my thesis, I have studied the effect of ligand field strength on the magnetic anisotropy and relaxation behavior in a series of mono- and dinuclear high-spin Co(II) complexes. Subsequently, I would conclude by giving an outlook on the probable applications of the above-mentioned systems in devices and quantum qubits.