Recent advances in mixed β-pyrrole substituted meso-tetraphenylporphyrins

The modulation of physicochemical properties of the porphyrin macrocycle could find applications in nonlinear optics, dye-sensitized solar cells, photodynamic therapy etc. The synthesis of such porphyrins is challenging and gaining considerable importance. By appending appropriate substituents at the β-pyrrole or meso-carbon positions of the macrocycle could modulate the frontier orbitals of the porphyrin π-system. The present review discusses the reported synthetic routes employed for various mixed β-pyrrole substituted meso-tetraphenylporphyrins. Further, earlier work over the past 15 years on the influence of mixed β-substituent pattern in the electronic spectral, electrochemical redox and stereochemistry of the porphyrin macrocycle will be briefly discussed in this review article including their future prospects.