Executive Summary : | Natural photosynthesis involves light energy is harvested in various types of antenna systems and funneled to ‘‘special pair’’ dimer of chlorophyll or bacteriochlorophyll pigments that instigate primary charge separation, ejecting an electron to become a dimer radical cation as a result generation of long-lived charge separated state. Photoinduced energy transfer (EnT) and photoinduced electron transfer (PET) are the two major events occurred during this phenomenon. A great variety of donor-acceptor systems using various scaffolds were reported in literature to understand the generation of long-lived charge separated species. Among these scaffolds, tetrapyrrolic systems particularly porphyrins are almost monopolize the study of photoactive arrays, due to their easy availability and large body of information on their synthetic manipulations, electrochemical and photophysical processes. In addition other tetrapyrrolic derivatives such as phthalocyanines, corrole, and core modified, expanded and contracted porphyrin based D-A systems also reported in the literature. Of these, corrole based D-A systems are relatively less in literature. A few corrole based D-A systems were reported in literature using either peripheral (meso phenyl or β-pyrrole) in a horizontal fashion or axial position/s of a resident metal/metalloid ion of corrole macrocyle ina vertical fashion. However, utilization of both peripheral and axial position/s simultaneously for construction of corrole based D-A systems were not reported till date. The main objective of the proposal is to construction of D-A systems based on Ge(IV) corroles in which an energy/electron donor tetraphenyl ethylene connected either at meso phenyl or at β-pyrrole position and an electron acceptor either perylene diimide or fullerene at axial position through covalent interactions. Further, we would like to construct D-A systems by using axial positions of Ge(IV) corrole using both non-covalent and covalent interactions. The photoexciation of Ge(IV) corrole initiate a PET reaction to axially substituted electron acceptor and the hole formed on corrole migrate to peripherally substituted donor and one can expect long-lived charge separated species. The rate of charge separated (kCS) and rate of charge recombination (kCR) will be compared between peripherally-axially substituted and axially substituted D-A conjugates. The understanding of long-lived charge separated species will not only useful in depth understand of natural photosynthesis but also useful in design of efficient materials for optoelectronic applications. |