@article {42428, title = {Lewis acid catalyzed selective reactions of donor-acceptor cyclopropanes with 2-naphthols}, journal = {Angewandte Chemie-International Edition}, volume = {55}, year = {2016}, month = {AUG}, pages = {10061-10064}, abstract = {

Lewis acid-catalyzed reactions of 2-substituted cyclopropane 1,1-dicarboxylates with 2-naphthols is reported. The reaction exhibits tunable selectivity depending on the nature of Lewis acid employed and proceed as a dearomatization/rearomatization sequence. With Bi(OTf)(3) as the Lewis acid, a highly selective dehydrative [3+2] cyclopentannulation takes place leading to the formation of naphthalene-fused cyclopentanes. Interestingly, engaging Sc(OTf)(3) as the Lewis acid, a Friedel-Crafts-type addition of 2-naphthols to cyclo-propanes takes place, thus affording functionalized 2-naphthols. Both reactions furnished the target products in high regioselectivity and moderate to high yields.

}, keywords = {annulations; arenes; Lewis acids; reaction mechanisms; small ring systems}, doi = {10.1002/anie.201604373}, author = {Kaicharla, Trinadh and Roy, Tony and Thangaraj, Manikandan and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article {43875, title = {Lewis acid catalyzed cascade annulation of alkynols with alpha-ketoesters: a facile access to gamma-spiroketal-gamma-lactones}, journal = {Chemical Communications}, volume = {53}, year = {2017}, month = {JUN}, pages = {6641-6644}, type = {Article}, abstract = {A novel Lewis acid catalyzed intermolecular cascade annulation of alkynols with alpha-ketoesters has been developed. This simple and efficient cascade annulation proceeds through a 5-exo-dig cyclization of alkynols followed by annulation with alpha-ketoester to provide a wide variety of unsaturated gamma-spiroketal-gamma-lactones (1,6-dioxaspiro[4.4]non-3-en-2-ones) related to many natural products.}, doi = {10.1039/c7cc03668j}, author = {Kambale, Digambar A. and Thorat, Sagar S. and Pratapure, Madhukar S. and Gonnade, Rajesh G. and Kontham, Ravindar} } @article {44353, title = { Lithium hydride as an efficient reagent for the preparation of 1,2-anhydro inositols: does the reaction proceed through {\textquoteright}axial rich{\textquoteright} conformation?}, journal = {Carbohydrate Research}, volume = {463}, year = {2018}, month = {JUL}, pages = {32-36}, type = {Article}, abstract = {scyllo-Inositol derived 1,2-trans-diequatorial halohydrins can be efficiently converted to the corresponding epoxides in the presence of lithium hydride. The structure of one of the epoxides was determined by single crystal X-ray diffraction analysis. This provides a potential route for the preparation of ring modified inositol derivatives. DFT calculations suggest that this epoxide formation could be proceeding through the intermediacy of the cyclohexane ring-inverted axial-rich conformer (1,2-trans-diaxial halohydrin). This is supported by the results of DFT calculations on the formation of inositol orthoformate, where the product is locked in the axial-rich conformation, while the starting inositol has the equatorial-rich conformation.}, doi = {10.1016/j.carres.2018.04.014}, author = {Sarkar, Nitai and Sardessai, Richa S. and Shashidhar, Mysore S. and Tamboli, Majid I. and Gonnade, Rajesh G.} } @article {46991, title = {Ligand structure directed dimensionality reduction (2D -> 1D) in lead bromide perovskite}, journal = {Journal of Physical Chemistry C}, volume = {124}, year = {2020}, month = {JAN}, pages = {1888-1897}, type = {Article}, abstract = {

Low dimensional (2D, 1D) lead halide perovskites are currently attracting huge research interest due to their enabling properties. Demonstrating synthetic control on the dimensionality/ structure of these perovskites is highly challenging. Dimensionality in these perovskites is largely dictated by the nature/structure and composition of the incorporating ligands and the utilized synthetic conditions. Here, we demonstrate chemical composition based control on reduction of dimensionality (2D -\> 1D) for lead bromide perovskite utilizing 2-(2-aminoethyl)isothiourea dihydrobromide as a common precursor ligand (Isothio Bromide). Controlling the hydrothermal reaction parameters (temperature, time) at a fixed precursor ratio affords corner-shared, contorted 2D sheet perovskite and corner-shared, contorted, chiral 1D chain perovskite. Such dimensionality reduction leads to contrasting photophysical properties: 1D chain perovskite shows long-lived and self-trapped broad band emission, whereas 2D perovskite shows short-lived, band edge emission with a long tail. Mechanistic studies and single crystal structure analysis reveal the incorporation of the utilized precursor ligand (Isothio Bromide) in 2D perovskite. Surprisingly, the 1D perovskite is found to be chiral (P2(1) space group) incorporating 2-(2-aminoethyldisulfanyl)ethanamine and ammonium ions as the achiral ligands generated in situ due to hydrothermal cleavage of the precursor (Isothio Bromide) ligand. Such structural and compositional change of the ligands, which manifests a different hydrogen bonding network in the resultant perovskite structure, plays a decisive role in dictating the final molecular formula and dimensionality/structure of the perovskite which largely controls their photophysical properties.

}, issn = {1932-7447}, doi = {10.1021/acs.jpcc.9b11033}, author = {Bakthavatsalam, Rangarajan and Haris, Muhammed P. U. and Shaikh, Samir R. and Lohar, Amruta and Mohanty, Ashutosh and Moghe, Dhanashree and Sharma, Shivani and Biswas, Chinmoy and Raavi, Sai Santhosh Kumar and Gonnade, Rajesh G. and Kundu, Janardan} } @article {47418, title = {Lead-free zero dimensional tellurium(iv) chloride-organic hybrid with strong room temperature emission as a luminescent material}, journal = {Journal of Materials Chemistry C}, volume = {9}, year = {2021}, month = {MAR }, pages = {4351-4358}, type = {Article}, abstract = {

Despite the current progress in {\textquoteleft}Pb-free{\textquoteright} low dimensional main group metal halide based luminescent materials, it is challenging to synthesize Te(iv) halide hybrids with strong ambient emission with excitation features in the visible range as efficient and stable phosphors for potential lighting applications. Reported here is a (benzyltriethylammonium)(2)TeCl6 zero dimensional hybrid material with excitation features in the visible range and strong room temperature, broadband, intrinsic luminescence (PLQY similar to 15\%) arising due to self-trapped excitons (STEs). Furthermore, a proof-of-concept LED architecture demonstrates successful optical down-conversion with a visible light excitation source. Here, exclusive adoption of a {\textquoteleft}regular{\textquoteright} octahedral Te(iv)-halide unit structure with minimal static distortion provides a unique opportunity to unmask the role played by 5s(2) lone pair electrons in shaping the emissive properties. This effort may open up new avenues towards unravelling the role of lone pair stereoactivity in controlling the PLQY in low dimensional hybrids that has proven to be challenging for the reported (Sb, Sn) based low dimensional 5s(2) metal halide hybrid materials.

}, issn = {2050-7526}, doi = {10.1039/d0tc05752e}, author = {Biswas, Anupam and Bakthavatsalam, Rangarajan and Bahadur, Vir and Biswas, Chinmoy and Mali, Bhupendra P. and Raavi, Sai Santosh Kumar and Gonnade, Rajesh G. and Kundu, Janardan} } @article {48154, title = {Luminescent magnesium complexes with intra- and inter-ligand charge transfer}, journal = {Chemical Communications}, volume = {58}, year = {2022}, month = {OCT}, pages = {11843-11846}, type = {Article}, abstract = {

Herein, we report two 2,2{\textquoteright}-pyridylpyrrolide (PyPyrH) ligand supported magnesium complexes (1 and 2), which demonstrate bright luminescence with a quantum yield of 22\% and 14\% in the solid state, respectively. Theoretical calculations reveal that their emissive properties originate from the intra- and inter-ligand charge transfer.

}, issn = {1359-7345}, doi = {10.1039/d2cc04142a}, author = {Kumar, Rohit and Pahar, Sanjukta and Chatterjee, Joy and Dash, Soumya Ranjan and Gonnade, Rajesh G. and Vanka, Kumar and Sen, Sakya S.} }