@article {48410, title = {Elliptically birefringent chemically tuned liquid crystalline nanocellulose composites for photonic applications}, journal = {Journal of Molecular Liquids}, volume = {366}, year = {2022}, month = {NOV }, pages = {120326}, type = {Article}, abstract = {

Cellulose nanocrystals (CNCs) based photonic materials are one of the promising materials in the recent trends. The liquid crystalline behavior of the CNCs can be tailored to different advanced applications. The proposed research investigates the potential of CNCs as an optically active material. CNCs were tuned to hydroxypropyl nano cellulose (HPNC) with the degree of substitution 1.39. The prepared liquid crystalline HPNC were dispersed in various concentrations of monomethyl ether of polyethylene glycol to get waterborne materials with specific optical anisotropy. The extraction, modification, and morphology of the CNCs were investigated using NMR (Nuclear Magnetic Resonance), TEM (Transmission Electron Microscopy), XRD (X-ray Powder Diffraction), and FESEM (Field Emission Scanning Electron Microscopy) analysis. The prepared HPNC was analyzed using a hot stage POM (Polarized Optical Microscope) for optical anisotropy. The thermal stability of prepared CNCs and HPNC was also investigated. Upon optimization using rheology and POM, it was found that at the ratio of 1:1, HPNC (5 wt\%) and mPEG (40 wt\%) had the most distinct optical properties. The potential of the prepared materials can be further explored in sensing, smart coating, and security materials. (C) 2022 Elsevier B.V. All rights reserved.

}, keywords = {bagasse, Cellulose nanocrystals, Elliptical birefringence, liquid crystals, optical anisotropy}, issn = {0167-7322}, doi = {10.1016/j.molliq.2022.120326}, author = {Singh, Shiva and Bhardwaj, Shakshi and Verma, Chhavi and Chhajed, Monika and Balayan, Kajal and Ghosh, Kaushik and Maji, Pradip K.} } @article {48126, title = {Six-membered saturated NHC-stabilized borenium cations: isolation of a cationic analogue of borinic acid}, journal = {Inorganic Chemistry}, volume = {61}, year = {2022}, month = {AUG}, pages = {12991-12997}, type = {Article}, abstract = {

The reaction of six-membered saturated NHC [1,3-di(2,6-diisopropylphenyl) tetrahydropyrimidine-2-ylidene; henceforth abbreviated as 6-SIDipp] with PhBCl2 yields a Lewis base adduct, 6-SIDipp.PhBCl2 (1), which readily undergoes nucleophilic substitution reaction with AgNO3, leading to the single (2) and double (3) substitution of both chlorides with ONO2 moieties at the boron atom. The reaction of 1 with 1 equiv of AlCl3 resulted in a borenium cation of composition [6-SIDipp.B(Ph)Cl]+ (4) with AlCl4- as the counteranion. Although borenium cations with different substituents on boron have been reported, a structurally characterized phenylchloroborenium cation remains unknown. Similarly, the reaction of 1 with triflic acid provides the first representative of a new class of borenium cations bearing one hydroxyl and one phenyl group on boron (5), a cationic analogue of borinic acid. Ph-BN H Diphenylborinic acid

}, issn = {0020-1669}, doi = {10.1021/acs.inorgchem.2c00611}, author = {Kundu, Gargi and Balayan, Kajal and Tothadi, Srinu and Sen, Sakya S.} } @article {48687, title = {On the competition between six-membered and five-membered NHC towards alane centered ring expansion}, journal = {Chemical Communications}, volume = {59}, year = {2023}, month = {JUL}, pages = {8540-8543}, type = {Article}, abstract = {

The combination of 6-SIDipp center dot AlH3 (1) and 5-IDipp resulted in the ring expansion of 6-NHC, while the five-membered NHC remained unchanged, which was subsequently explained by DFT studies. Besides, the substitution chemistry of 1 was also studied with TMSOTf and I-2, which gave rise to the substitution of a hydride by triflate or iodide ligands.

}, issn = {1359-7345}, doi = {10.1039/d3cc02063k}, author = {Balayan, Kajal and Sharma, Himanshu and Vanka, Kumar and Ravindranathan, Sapna and Gonnade, Rajesh G. and Sen, Sakya S.} }