Executive Summary : | Photoswitches are photochromic molecules that can reversibly switch between two or more isomeric states by irradiating suitable wavelengths of light. Azoheteroarenes, derived from five-membered and –N-based heterocycles, have gained attention for applications such as spin-crossover, medicinal chemistry, and storage devices. The key challenge is to bring maximal changes in their physical properties upon photoswitching in those metal complexes. For an excellent Photoswitching Magnetic Molecule (PSM), one or more photoresponsive units should be present within the ligand framework and complexed with transition metals (Fe, Co, Ni, and Cu) to exhibit improved bistability by light. The chemistry of PSMs complexed with transition metal complexes is relatively an unexplored area, and achieving spin cross over molecules requires considering factors such as coordination modes, electronic spectral overlaps, and differences in magnetic properties. To address these issues and improve design, state-of-the-art computational methods (Density Functional Theory (DFT)/ab initio) will be used. The PSM will be modelled using the primary ligand framework formed from pyrazole, triazole, and tetrazole units, and the structures will be studied to understand how the –N atoms in the heterocyclic system affect photoswitability. The influence of substituents, electron donating and withdrawing groups, ring connectivity, and ring substitution will also be studied. DFT computations with high-accuracy functionals will be used to optimize the modelled complexes, and the optimized structure will be used to compute photochemical properties such as E-Z isomerization and spectral properties. |