@article {46332, title = {Regioselective one-pot synthesis of 3-fluoro-imidazo[1,2-a]pyridines from styrene}, journal = {Asian Journal of Organic Chemistry}, year = {2019}, month = {OCT}, type = {Article; Early Access}, abstract = {

A one-pot synthesis of C-3 fluorinated imidazopyridines (F-IMPY) is reported under the additive-free conditions from commercially available styrene and 1-fluoropyridinium tetrafluoroborate as a fluorine source. The substrate styrene undergoes keto-bromination/condensation/fluorination transformation in three sequential steps to furnish F-IMPY. This one-pot synthesis method exhibits broad substrate scope and good functional group tolerance with a good yield (up to 82\%).

}, keywords = {fluorination, imidazopyridines (F-IMPY), One-pot synthesis}, issn = {2193-5807}, doi = {10.1002/ajoc.201900521}, author = {Said, Madhukar S. and Mishra, Ankita and Pandole, Satish and Nayak, Rashmi A. and Kumar, Pradeep and Gajbhiye, Jayant M.} } @article {46824, title = {Conjunctive photoluminescence enhancement through plasmonic and photonic band-gap pathways in a chiral self-assembled system}, journal = {ChemPhotoChem}, volume = {4}, year = {2020}, month = {AUG}, pages = {582-591}, type = {Article}, abstract = {

We describe two parallel pathways for enhancing the intrinsic photoluminescence of an organic emitter dispersed in a liquid crystal (LC) medium. The pathways have independent origins: (i) Metal enhanced fluorescence (MEF) incorporating gold nanoparticles having an organic shell of pro-mesogenic cholesterol esters; and (ii) Matching the photonic band gap (PBG) due to the helical structure in a self-assembled chiral system with the excitation wavelength. This unprecedented combination of both pathways achieves a level of photoluminescence exceeding the sum of the contribution from the individual methods. This conjunctive protocol results in an overall enhancement by a factor of 37 between the emitter dispersed in a non-chiral LC and that appealing to both MEF and PBG pathways. Circular polarized luminescence measurements also show that this protocol helps in effective discrimination of chiral light achieving a large dissymmetry factor whose magnitude (+0.33) is comparable to the highest recorded to date. Electric field switching between two states is also shown to result in appreciable fluorescence modulation. Being generic in nature the protocol employed can be adapted to a variety of situations with the large magnitude as well the modulation level suitable for applications such as biosensors, various analyte detection, and other photonic devices.

}, keywords = {chirality, circularly polarized luminescence, liquid crystals, photonic band-gap, plasmonics}, issn = {2367-0932}, doi = {10.1002/cptc.202000077, Early Access Date = JUN 2020}, author = {Baral, Marlin and Krishna Prasad, S. and Bhat, Sachin A. and Nayak, Rashmi A. and Yelamaggad, C. V.} } @article {47078, title = {Aggregation-induced phosphorescence of an anthraquinone based emitter}, journal = {Organic \& Biomolecular Chemistry}, volume = {19}, year = {2021}, month = {FEB }, pages = {1004-1008}, type = {Article}, abstract = {

Room temperature phosphorescence (RTP) of metal-free organic molecules is a hot topic of current research interest. RTP can be enhanced through aggregation, crystallization, and the support of polymers and host-guest assemblies. The characteristics of highly phosphorescent aggregates formed from conventional chromophores make them ideal candidates for many potential applications. In this direction, we focused on the aggregation-induced phosphorescence of an anthraquinone derivative AqC6 in solution and in crystal state. The weakly emissive dilute solution exhibits a tunable emission with enhanced intensity and room temperature phosphorescence by increasing the concentration and solvent-antisolvent combination. The enhanced phosphorescence of crystals has been recreated in the solution by making use of aggregation. Interestingly, the support of PMMA enabled AqC6 to achieve enhanced processability, phosphorescence lifetime (174 ms) and quantum yield (5\%).

}, issn = {1477-0520}, doi = {10.1039/d0ob02505d}, author = {Goudappagouda and Nidhankar, Aakash D. and Nayak, Rashmi A. and Babu, Sukumaran Santhosh} }