Executive Summary : | This project aims to achieve air and thermally stable carbon centered radicals with one neighboring sp3 hybridized carbon. The synthetic manipulation involves in situ generation of molecules with hydrogen substitution on the two adjacent sp3 hybridized carbon centers. Oxygen mediated syntheses are unstable and typically obtained as reaction intermediates in organic syntheses. In this project, oxygen will play a key role in preparing air and thermally stable radical species. The stable organic radicals generated will be easily separated by filtration or other separating processes from the reaction mixture. The continuous separation process will favor reaction equilibrium. In addition to oxygen, the project introduces sigma- and pi-dimerization processes of biradicals, which are achieved by adjusting electron donating and withdrawing groups in the fluorophore. The overall push-pull effect between the donor and acceptor will lower the energy barrier for the single electron transfer process, converting the singlet state to the triplet biradical. The sigma-dimerization through the electron withdrawing group will be utilized for the synthesis of emissive biradical species. The temperature-dependent sensitivity of antiferromagnetic interaction will be explored for biomolecule sensing purposes. The most challenging part of this project is the bio-imaging applications. Recent reports by Ben Zhong Tang open imaging pathways for radical cations. The project will utilize heterocyclic rings to enhance the water solubility of the radical species for imaging purposes. The hypothesis is that oxygen and water mediated air stable fluorescent organic radical synthetic routes will open new avenues for organic transformation and bioimaging studies. |