@article { ISI:000226532100006, title = {Factors affecting activation and utilization of carbon dioxide in cyclic carbonates synthesis over Cu and Mn peraza macrocyclic complexes}, journal = {Journal of Molecular Catalysis A - Chemical}, volume = {226}, number = {2}, year = {2005}, month = {FEB}, pages = {199-205}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The catalytic activities of several Cu and Mn aza complexes for cyclic carbonate synthesis from CO2 and epoxides are reported. The various factors affecting activation of CO2 by metal complexes and its utilization in cyclic carbonate synthesis have been investigated. Fr-IR, UV-vis and EPR spectroscopic investigations reveal that CO2 coordinates to Cu in eta(1)-C mode of coordination. Nature of the ligand and substitution influence the lability of metal-CO2 bonding. The differences in the catalytic activities are correlated with the mode and strength of CO2 binding. (C) 2004 Elsevier B.V. All rights reserved.

}, keywords = {benign synthesis, Carbon dioxide, catalysis by Cu and Mn complexes, CO2 activation, CO2 fixation, CO2 utilization, cyclic carbonates, polycarbonates, spectroscopy}, issn = {1381-1169}, doi = {10.1016/j.molcata.2004.10.034}, author = {Srivastava, R. and Bennur, T. H. and Srinivas, D.} } @article { ISI:000239975900022, title = {In situ optical emission spectroscopic investigations during arc plasma synthesis of iron oxide nanoparticles by thermal plasma}, journal = {IEEE Transactions on Plasma Science}, volume = {34}, number = {4, 1}, year = {2006}, month = {AUG}, pages = {1175-1182}, publisher = {IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC}, type = {Article}, address = {445 HOES LANE, PISCATAWAY, NJ 08855 USA}, abstract = {

Investigations using in situ precursor spectroscopy during the growth of nanoparticles of iron oxide by thermal plasma induced gas phase condensation method have been shown to be useful for correlating the size of nanoparticles with existing plasma parameters. The relative abundance of ionized Fe species inside the plasma plume is seen to directly establish the relation between particle size, arc current, arc length, and ambient pressure of the reacting oxygen gas. The argon plasma from a transferred arc reactor is made to impinge on the anode that is allowed to vaporize and react with oxygen. The spectral line profiles of both Ar and Fe along the plasma column during the synthesis of nanoparticles have been proved to be useful in understanding the growth mechanism. Band intensities of FeO molecular states indicated the inverse relation with particle sizes that have been correlated to the two competitive processes in which energy is released, namely: 1) one involving the radiative transition and 2) the other that of the growth by coagulation. Atomic Boltzmann plots are used for estimating the temperatures of the zones, whereas particle sizes have been inferred using transmission electron microscopic measurements.

}, keywords = {plasma arc device, plasma-materials processing applications, spectroscopy}, issn = {0093-3813}, doi = {10.1109/TPS.2006.878430}, author = {Banerjee, Indrani and Joshi, N. K. and Sahasrabudhe, S. N. and Kulkarni, Naveen V. and Karmakar, Soumen and Pasricha, R. and Ghorui, S. and Tak, Atul K. and Murthy, Shri P. S. S. and Bhoraskar, S. V. and Das, A. K.} } @article { ISI:000247807900003, title = {Synthesis and characterization of novel polyurethanes based on 4,4 {\textquoteleft}-[1,4-phenylenedi-diazene-2,1-dlyl] bis(2-carboxyphenol) and 4,4 {\textquoteleft}-[1,4-phenylenedi-diazene-2,1-diyl] bis(2-chlorophenol) hard segments}, journal = {Reactive \& Functional Polymers}, volume = {67}, number = {6}, year = {2007}, month = {JUN}, pages = {503-514}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Eight novel polyurethanes (PUs) based on 4,4{\textquoteright}-[1,4-phenylenedi-diazene-2,1-diyl]bis(2-carboxyphenot) and 4,4{\textquoteright}-[1,4phenylenedi-diazene-2,1-diyl]bis(2-chloro- phenol) as hard segments with four diisocyanates viz., 4,4-diphenyl-methane diisocyanate, toluene 2,4-diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate were prepared. Structural and thermal characterization of the segmented PUs were determined by FT-IR, UV spectrophotometry, fluoroscence spectroscopy, H-1 NMR, C-13 NMR spectroscopy and DTA/TGA analysis. All the PUs contain domains of semi-crystalline and amorphous structures, as indicated by X-ray diffraction. PUs were soluble in polar aprotic solvents like N-methyl-2-pyrrolidone (NMP), dimethyl formamide (DMF) and dimethylsulfoxide (DIVISO). (c) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {azo polymers, fluorescence, hard segments, Morphology, phase separation, polyurethanes, spectroscopy, Thermal properties}, issn = {1381-5148}, doi = {10.1016/j.reactfunctpolym.2007.02.003}, author = {Raghu, A. V. and Gadaginamath, G. S. and Mathew, Nevin T. and Halligudi, Shivaraj B. and Aminabhavi, Tejraj M.} } @article { ISI:000381593700007, title = {Spectroscopy and catalytic activity study of gold supported on barium titanate nanotubes for styrene epoxidation}, journal = {Applied Catalysis A-General}, volume = {523}, year = {2016}, month = {AUG}, pages = {61-72}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Gold (0.5-5 wt.\%) supported on barium titanate nanotubes (Au/BaTNT) were prepared, characterized and for the first time, investigated as catalysts for selective oxidation of styrene with oxygen (O-2 or H-2 + O-2) and peroxides (H2O2 or TBHP). Conversion of styrene enhanced when H-2 was co-added to O-2 in the reactions. Au/BaTNT activated O-2 and H-2 and produced H2O2 in situ for use in oxidations. Peroxides were found better oxidants than O-2. At optimized conditions, styrene oxide selectivity of 80.1 wt.\% at styrene conversion of 60.5 wt.\% was achieved over Au(1 wt.\%)/BaTNT using TBHP. Au particles (5.0-7.4 nm) were dispersed and decorated on the walls of BaTNT. They exhibited superior performance to the known Au catalysts in styrene oxidation. Reactive oxygen species formed during oxidation reactions were followed with in situ spectral characterizations (diffuse reflectance UV-vis and FT -Raman). Au/BaTNT was reusable in four recycles with little loss in catalytic activity. (C) 2016 Elsevier B.V. All rights reserved.

}, keywords = {Au Nanoparticles, reactive oxygen species, spectroscopy, Styrene Oxidation, Titanate nanotubes}, issn = {0926-860X}, doi = {10.1016/j.apcata.2016.05.014}, author = {Nepak, Devadutta and Srinivas, Darbha} } @article {46007, title = {Quantification of niclosamide polymorphic forms - a comparative study by Raman, NIR and MIR using chemometric techniques}, journal = {Talanta}, volume = {199}, year = {2019}, month = {JUL }, pages = {679-688}, type = {Article}, abstract = {

Niclosamide, an anthelmintic drug recently repurposed for its activity against cancer, crystallizes into three solvated forms, two monohydrates (NHa, NHb) and one anhydrous (NAn) form. NAn is sensitive to pseudopolymorphic transformations that affect its dissolution and consequently, its bioavailability. NAn exhibits a polymorphic conversion to metastable monohydrate (NHa) form during high-energy milling in presence of poorly soluble solvents like water. It is hence very important to quantify polymorphic conversion from NAn to NHa, as water is a commonly used solvent during various processing like ball milling and wet granulation. This main objective of the study was to examine the feasibility of Raman, NIR and MIR spectroscopic techniques for identification and quantification of polymorphic forms of niclosamide in binary mixtures and multicomponent mixtures. Calibration models were developed and validated by vibrational spectroscopic techniques in binary mixtures of NAn and NHa and in multicomponent mixtures by chemometric techniques. These techniques were further used to identify and quantify NHa during ball milling, granulation and in presence of other polymorphic forms of niclosamide. Identification and quantification of pseudopolymorphs in binary and multicomponent mixtures with an acceptable recovery of 100.13-102.99\% for Raman and 100.07-101.28\% for NIR with low \% RSD of 2.38-3.12 for both techniques were obtained. The \% NHa determined during ball milling and granulation was similar by NIR and Raman. Raman spectroscopy however showed a greater advantage over other techniques in determining the NHa in presence of NHb due to significant difference in the spectral region of hydrates, when compared to NIR and MIR.

}, keywords = {Ball milling, Granulation, MSC, PLS, Polymorphic conversion, spectroscopy}, issn = {0039-9140}, doi = {10.1016/j.talanta.2019.03.027}, author = {Bhavana, Valmala and Chavan, Rahul B. and Mannava, M. K. Chaitanya and Nangia, Ashwini and Shastri, Nalini R.} } @article {49240, title = {Exploring defect-engineered metal-organic frameworks with 1,2,4-triazolyl isophthalate and benzoate linkers}, journal = {INORGANIC CHEMISTRY}, volume = {63}, year = {2024}, month = {MAY }, pages = {10843-10853}, type = {Journal Article}, keywords = {Separation, spectroscopy, TRIAZOLYL}, issn = {0020-1669}, doi = {10.1021/acs.inorgchem.4c01589}, author = {Chetry, Sibo and Lukman, Muhammad Fernadi and Bon, Volodymyr and Warias, Rico and Fuhrmann, Daniel and Moellmer, Jens and Belder, Detlev and Gopinath, Chinnakonda S. and Kaskel, Stefan and Poeppl, Andreas and Krautscheid, Harald} } @article {49249, title = {Viscosity effects on the dynamics of diols and diol-based deep eutectic solvents}, journal = {Photochemistry and Photobiology}, volume = {100}, year = {2024}, month = {JUL}, pages = {946-955}, type = {Article}, abstract = {

Diols, characterized by the presence of two hydroxyl groups, form extended hydrogen-bonded networks. Increasing hydrocarbon chain length is known to elevate the viscosity of diols. Given the established influence of viscosity on solvent dynamics, it becomes imperative to comprehend the impact of viscosity on the fluctuation dynamics within diols and establish connections with hydrogen bond formation and breaking dynamics. In this study, we employ two-dimensional infrared spectroscopy to investigate the viscosity dependence of the structural evolution dynamics in three diols with varying chain lengths. Complementing our experimental approach, molecular dynamics simulations are conducted to extract hydrogen bond lifetimes. Our findings reveal a linear correlation between bulk viscosity, solvent fluctuation timescales, and hydrogen bond lifetimes. Notably, the selected diols exhibit the capability to form deep eutectic solvents upon mixing with choline chloride at specific molar ratios. In contrast to molecular solvents like diols, deep eutectic solvents are characterized by the formation of heterogeneous nanodomains, comprising various intercomponent hydrogen-bonded networks. Interestingly, our observations indicate that while the fluctuation dynamics decelerate with increasing bulk viscosity in diol-based deep eutectic solvents, the relationship between viscosity and dynamics is not linear, in contrast to the observed linearity in diols. This nuanced understanding contributes to the broader comprehension of the interplay between viscosity and dynamics in both molecular and deep eutectic solvents. We investigate the impact of viscosity on structural evolution dynamics in diols with varying chain lengths. Employing two-dimensional infrared spectroscopy and molecular dynamics simulations, we explore the relationship between bulk viscosity, solvent fluctuation timescales, and hydrogen bond lifetimes. We report a linear correlation in diols between viscosity, fluctuation timescales, and hydrogen bond lifetimes. Diols also form deep eutectic solvents, characterized by heterogeneous nanodomains. While fluctuation dynamics slow down with increasing bulk viscosity in diol-based deep eutectic solvents, the relationship between viscosity and dynamics is nonlinear, contrasting with diols{\textquoteright} linearity. This understanding enhances comprehension of viscosity-dynamics interplay in molecular and deep eutectic solvents.image

}, keywords = {Dynamics, Hydrogen bond, solvent, spectroscopy, viscosity}, issn = {0031-8655}, doi = {10.1111/php.13950}, author = {Chatterjee, Srijan and Deshmukh, Samadhan H. and Chowdhury, Tubai and Bagchi, Sayan} }