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Bachcha Singh

Bio: Bachcha Singh is an academic researcher from Banaras Hindu University. The author has contributed to research in topics: Mesophase & Liquid crystal. The author has an hindex of 13, co-authored 89 publications receiving 545 citations.


Papers
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Journal ArticleDOI
TL;DR: In this article, metal(II) complexes of the types [M(L)2Cl2]·H2O and [Cu(4-HOABH)SO4(H 2O)2] were prepared and characterized by elemental and thermal analyses, molar conductance, infrared, ESR and electronic spectral studies.
Abstract: Metal(II) complexes of the types [M(L)2Cl2]·H2O and [Cu(4-HOABH)SO4(H2O)2] [M═Co(II), Ni(II), Cu(II) and Cd(II), L=acetophenone benzoylhydrazone (ABH), C6H5CONHN = C(CH3)C6H5 and 4-hydroxyacetophenone benzoylhydrazone (4-HOABH), C6H5CONHN = C(CH3)C6H4OH], were prepared and characterized by elemental and thermal analyses, molar conductance, infrared, ESR and electronic spectral studies. Some of the complexes were screened against E. coli and Aspergillus niger for biological activity.

4 citations

Journal ArticleDOI
TL;DR: The resulting models could act as an efficient strategy for estimating the hypoxic conditions through imaging and provide some insights into the structural features related to the biological activity of these compounds.
Abstract: Copper(II) bis(thiosemicarbazone) are very useful for blood flow and hypoxic imaging. The aim of this study was to identify structure-activity relationships (SARs) within a series of analogues with different substitution patterns in the ligands, in order to design improved hypoxia imaging agents and elucidate hypoxia selectivity mechanisms. Genetic algorithms (GAs) were used to develop specific copper metal-ligand force field parameters for the MM3 force-field calculations. These new parameters produced results in good agreement with experiment and previously reported copper metal-ligand parameters. A successful quantitative SAR (QSAR) for predicting the several classes of Cu(II)-chelating ligands was built using a training set of 21 Cu(II) complexes. The QSAR exhibited a correlation between the predicted and experimental test set. The QSAR preformed with great accuracy; r(2) = 0.95 and q(2) = 0.90 utilizing a leave-one-out cross-validation with multiple linear regression analysis to find correlation between different calculated molecular descriptors of these complexes. The final QSAR mathematical models were found as the following: Log P = {3.01698 (+/-0.0590)} - LUMO {0.1248 (+/-0.068)} + MR {0.3219 (+/-0.086)} n = 21 |r| = 0.972 s = 0.188 F = 98.102 The resulting models could act as an efficient strategy for estimating the hypoxic conditions through imaging and provide some insights into the structural features related to the biological activity of these compounds.

4 citations

Journal ArticleDOI
TL;DR: A new series of mesogenic unsymmetrical azines, N-(o-hydroxybenzylidene)-N′-(4-n-alkoxybenzoyloxy benzylidsene)azines, HOC6H4CH˭N-N˭CHC 6H4OCOC6h4O CmH2m+1 (m = 7, 8, 9, 10, 11, 12, 14, and 16) have been prepared as discussed by the authors.
Abstract: A new series of mesogenic unsymmetrical azines, N-(o-hydroxybenzylidene)-N′-(4-n-alkoxybenzoyloxybenzylidene)azines, HOC6H4CH˭N-N˭CHC6H4OCOC6H4O CmH2m + 1 (m = 7, 8, 9, 10, 11, 12, 14, and 16) have been prepared. They have been characterized by elemental analyses, FT-IR, UV-visible, 1H, and 13C NMR (Nuclear Magnetic Resonance) spectra. The mesomorphic properties of these compounds were investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The azines m = 7, 10, and 14 exhibit features of enantiotropic nematic (N) mesophase whereas azines m = 8, 11 exhibit features of a monotropic nematic phase. The azines m = 9, 12, and 16 do not exhibit mesogenic nature.

4 citations

Journal ArticleDOI
TL;DR: A series of transition metal complexes K[MII(s-bqdi)2][FeIII(s -bqDI)2(CN)2]· 10H2O (s- bqdi,= semibenzoquinonediiminate, MII(2), Ni (3), and Cu (4)) have been synthesized.
Abstract: A new series of transition metal complexes K[MII(s-bqdi)2][FeIII(s-bqdi)2(CN)2] · 10H2O (s-bqdi = semibenzoquinonediiminate, MII = Co (2), Ni (3), and Cu (4)) have been synthesized. These complexes have been characterized by elemental analyses, FT IR, Far IR, FAB mass, UV-Vis, TGA, CV measurements, and powder XRD. The powder XRD patterns of 2, 3, and 4 show that they are isostructural with hexagonal primitive lattice structures. The coordination polymers display 1-D chain networks. Magnetic properties of the CoIIFeIII complex studied by a SQUID magnetometer reveal low-temperature antiferromagnetic interaction.

4 citations


Cited by
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Journal ArticleDOI
01 Jan 1889

595 citations

Book ChapterDOI
01 Jan 1991
TL;DR: The nature of metal complexes of heterocyclic thiosemicarbazones reported in the literature through 1989 have been reviewed with an emphasis on variations in stoichiometry and stereochemistry as discussed by the authors.
Abstract: The nature of metal complexes of heterocyclic thiosemicarbazones reported in the literature through 1989 have been reviewed with an emphasis on variations in stoichiometry and stereochemistry. A brief introduction is followed by a survey of the biological activity of the uncomplexed thiosemicarbazones. Next is a section on the chemical nature of thiosemicarbazones including a discussion of preparative methods, modes of coordination and isomerism. This is followed by a discussion of structural information and biological activity of the iron(III), iron(II), copper(II), cobalt(III), cobalt(II) and nickel(II) complexes of heterocyclic thiosemicarbazones. Short sections on the biological activity of other chelating thiosemicarbazones and metal complexes are also included.

435 citations

Journal ArticleDOI
TL;DR: A facile one-step, low-temperature, nonhydrolytic approach to in situ synthesizing amino-functionalized TiO2 nanoparticles (abbreviated as NH2 -TiO2 NPs) is developed by chemical bonding of amino (-NH2 ) groups, via TiN bonds, onto the surface of TiO1 NPs.
Abstract: Titanium oxide (TiO2 ) has been commonly used as an electron transport layer (ETL) of regular-structure perovskite solar cells (PSCs), and so far the reported PSC devices with power conversion efficiencies (PCEs) over 21% are mostly based on mesoporous structures containing an indispensable mesoporous TiO2 layer. However, a high temperature annealing (over 450 °C) treatment is mandatory, which is incompatible with low-cost fabrication and flexible devices. Herein, a facile one-step, low-temperature, nonhydrolytic approach to in situ synthesizing amino-functionalized TiO2 nanoparticles (abbreviated as NH2 -TiO2 NPs) is developed by chemical bonding of amino (-NH2 ) groups, via TiN bonds, onto the surface of TiO2 NPs. NH2 -TiO2 NPs are then incorporated as an efficient ETL in n-i-p planar heterojunction (PHJ) PSCs, affording PCE over 21%. Cs0.05 FA0.83 MA0.12 PbI2.55 Br0.45 (abbreviated as CsFAMA) PHJ PSC devices based on NH2 -TiO2 ETL exhibit the best PCE of 21.33%, which is significantly higher than that of the devices based on the pristine TiO2 ETL (19.82%) and is close to the record PCE for devices with similar structures and fabrication procedures. Besides, due to the passivation of the surface trap states of perovskite film, the hysteresis of current-voltage response is significantly suppressed, and the ambient stability of devices is improved upon amino functionalization.

197 citations

Journal ArticleDOI
TL;DR: In this article, the authors summarized the published innovations in nanomaterial-based optical sensors for the detection of Hg 2+ according to different sensing strategies, including colorimetric, fluorescent and surface enhanced Raman scattering detection.
Abstract: As one of the most toxic heavy metals, mercury ion (Hg 2+ ) has become a concern focus for its severe threats to environment and human health. As a result, it is of great importance to develop novel methods to realize the recognition and quantification of Hg 2+ . The past decades witness the development of nanomaterial-based optical sensors for Hg 2+ detection, showing the benefits of simplicity, rapidity, high sensitivity and selectivity, and cost-effectiveness. The reported methods have allowed the detectability down to nanomolar concentrations or much lower levels, and proved their practical applications for detecting and quantifying Hg 2+ in synthetic solutions or natural water samples. In this review, we summarize the published innovations in nanomaterial-based optical sensors for the detection of Hg 2+ according to different sensing strategies, including colorimetric, fluorescent and surface enhanced Raman scattering detection. Moreover, some challenges and significant attempts related to these methods are also discussed.

191 citations

Journal ArticleDOI
TL;DR: The experimental results suggest that the adsorption efficiency of DOX is dominated by the strong complexation, electrostatic interactions between DOX molecules and the Cu-BC samples, which hold the significant potential for enhancing the effectiveness to remove DOX from water.

146 citations