| dc.description.abstract | Modern life without magnetic materials is almost impossible to imagine. Mobile
phones, telecommunication, navigation, computer, television, credit cards, medical
equipment, data storage devices, and sensors are an integral part of modern life. The demand
and supply ratio of data storage devices is increasing day by day. To mitigate this, tremendous
effort is required toward the synthesis and development of high-density data storage devices.
Molecular systems exhibiting bistability i.e., a controlled and reversible change in their
physical properties by external stimuli have a tremendous possibility in molecular-scale
electronics e.g., data storage device, molecular qubits, quantum technology, molecular
spintronics, and nanotechnological application. In particular, molecular magnetism is a rapidly
growing field where molecules exhibiting photo- and thermo-chromism are of potential
interest. In this thesis, I have adopted a unique ‘complex as a ligand’ strategy to rationally
design and synthesize switchable molecular magnetic materials which exhibit interesting
physical properties such as single-molecule magnet (SMM), spin crossover (SCO), metal-tometal electron transfer (MMET) and electrical and thermal conductivity. A series of new
multifunctional homo-/hetero-bimetallic [Fe2Co2], [Fe2Fe2], and [Fe2Mn2] complexes have
been synthesized using a molecular approach. To understand better the contributing factors
for MMET properties, for example, ligand field effect, cooperativity, crystal matrix, and
electronic factors, we have performed detailed structural, magnetic, optical, spectroscopic,
and other physical characterization. Interestingly, some of these systems show interesting
on/off photo-switching and thermo- and photo-induced hysteresis effects. I have performed
a detailed study of the photo-induced metastable state along with the high-temperature
magneto-structural investigation. In other parts of my thesis, I have studied the singlemolecule magnet behavior in highly anisotropic Co(II) complexes and the spin state switching
behavior in Co(II) mono- and polymeric systems. In the last part of my thesis, I have coupled
both spin crossover and luminescence properties in a coordination polymer in which
concomitant change in both spin state and luminescence has been observed. Finally, I have
discussed the application of these switchable materials in optoelectronic devices. | en_US |
