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141.
Sumantra Bhattacharya Nayana Vaval Sourav Pal 《International journal of quantum chemistry》2013,113(12):1690-1695
The complex absorbing potential along with correlated independent particle potential (CIP) Fock space multireference coupled cluster method is used for the study of resonances. We have studied shape resonance of e?‐ F2, e?‐ N2O and e?‐CO molecules. In particular, we have studied e?‐ F2 scattering at different bond lengths to know whether is bound at the equilibrium bond length of F2. © 2013 Wiley Periodicals, Inc. 相似文献
142.
Dipakranjan Mal Amit Jana Sutapa Ray Sourav Bhattacharya Asit Patra Saroj R. De 《合成通讯》2013,43(22):3937-3946
DBU-CH3I has been poised to be a substitute for diazomethane in the preparation of methyl esters from carboxylic acids. The reactions can be carried out in commercial untreated acetone and acetonitrile, which have been exemplified with several methyl esters, otherwise it is difficult to prepare. Bis-esterification using diiodomethane can also be achieved in a similar fashion. Sufficiently acidic phenols are also conveniently O-methylated by the method. 相似文献
143.
Sourav Kar Subhash Bairagi Gaurav Joshi Prof. Dr. Eluvathingal D. Jemmis Prof. Dr. Sundargopal Ghosh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(63):15634-15637
Despite the synthesis and structural characterization of closo-hydroborate dianions, [BnHn]2− (n=6–12) more than 50 years ago, some ambiguity remains about the structure of [B8H8]2−. Although the solid-state structure of [B8H8]2− was established by single-crystal X-ray studies in 1969, fast rearrangements in solution at accessible temperatures prevented its detailed characterization. We therefore stabilized a derivative of [B8H8]2− by using Cp2MBH3 and structurally characterized two new octaborane analogues, [(Cp2MBH3)2B8H6] (Cp=η5-C5H5; M=Zr ( 1-Zr ) and Hf ( 1-Hf )), so that the dynamics of the B8 skeleton were arrested. The solid-state structures of both 1-Zr and 1-Hf comprise a dodecahedron core protected by {Cp2MBH3} moieties on both sides of the cluster. Spectroscopic characterization (11B NMR) validates the intactness of the B8 dodecahedron core in solution as well. Theoretical calculations establish that the two exo-{Cp2MBH3} fragments provide structural and electronic structural stability to the B8 core and its intact dodecahedral dianionic nature. Furthermore, we propose isodesmic equations for the formation of higher analogues of the Bn core (n>8) guarded by different group 4 transition metals. Our analysis suggests that, as we move to higher polyhedra (n>10), the formation becomes unfavourable irrespective of metal. 相似文献
144.
Photosensitizing assemblies of pyrazine derivative PDA have been developed which exhibit a high photostability, ‘lighted’ excited state, balanced redox potential, high transportation potential and activate oxygen via type-I pathway only. These PDA assemblies in combination with Cu(II) ions catalyze the CuAAC reaction via in situ reduction of Cu(II) ions without any reducing or stabilizing agent. The present protocol has wide substrate scope with recyclability of the catalytic system up to six catalytic cycles and is applicable to gram-scale synthesis. 相似文献
145.
Roy Sourav Singha Sarkar Sriparna Chakraborty Debashis 《Journal of inclusion phenomena and macrocyclic chemistry》2021,100(1-2):1-36
Journal of Inclusion Phenomena and Macrocyclic Chemistry - In the twenty-first century, one of the central focus of polymer research in academia and industries is directed towards the design of... 相似文献
146.
Light Harvesting and Directional Energy Transfer in Long‐Lived Homo‐ and Heterotrimetallic Complexes of FeII,RuII, and OsII 下载免费PDF全文
Dinesh Maity Chanchal Bhaumik Sourav Mardanya Srikanta Karmakar Dr. Sujoy Baitalik 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(41):13242-13252
A new family of trimetallic complexes of the form [(bpy)2M(phen‐Hbzim‐tpy)M′(tpy‐Hbzim‐phen)M(bpy)2]6+ (M=RuII, Os; M′=FeII, RuII, Os; bpy=2,2′‐bipyridine) derived from heteroditopic phenanthroline–terpyridine bridge 2‐{4‐[2,6‐di(pyridin‐2‐yl) pyridine‐4‐yl]phenyl}‐1H‐imidazole[4,5‐f][1,10]phenanthroline (phen‐Hbzim‐tpy) were prepared and fully characterized. Zn2+ was used to prepare mixed‐metal trimetallic complexes in situ by coordinating with the free tpy site of the monometallic precursors. The complexes show intense absorptions throughout the UV/Vis region and also exhibit luminescence at room temperature. The redox behavior of the compounds is characterized by several metal‐centered reversible oxidation and ligand‐centered reduction processes. Steady‐state and time‐resolved luminescence data show that the potentially luminescent RuII‐ and OsII‐based triplet metal‐to‐ligand charge‐transfer (3MLCT) excited states in the triads are quantitatively quenched, most likely by intercomponent energy transfer to the lower lying 3MLCT (for Ru and Os) or triplet metal‐centered (3MC) excited states of the FeII subunit (nonluminescent). Interestingly, iron did not adversely affect the photophysics of the respective systems. This suggests that the multicomponent molecular‐wire‐like complexes investigated here can behave as efficient light‐harvesting antennas, because all the light absorbed by the various subunits is efficiently channeled to the subunit(s) in which the lowest‐energy excited states are located. 相似文献
147.
Koushik Saha Sagar Ghorai Sourav Kar Suvam Saha Rajarshi Halder Beesam Raghavendra Eluvathingal D. Jemmis Sundargopal Ghosh 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(49):17848-17853
The room‐temperature reaction of [Cp*TaCl4] with LiBH4?THF followed by addition of S2CPPh3 results in pentahydridodiborate species [(Cp*Ta)2(μ,η2:η2‐B2H5)(μ‐H)(κ2,μ‐S2CH2)2] ( 1 ), a classical [B2H5]? ion stabilized by the binuclear tantalum template. Theoretical studies and bonding analysis established that the unusual stability of [B2H5]? in 1 is mainly due to the stabilization of sp2‐B center by electron donation from tantalum. Reactions to replace the hydrogens attached to the diborane moiety in 1 with a 2 e {M(CO)4} fragment (M=Mo or W) resulted in simple adducts, [{(Cp*Ta)(CH2S2)}2(B2H5)(H){M(CO)3}] ( 6 : M=Mo and 7 : M=W), that retained the diborane(5) unit. 相似文献
148.
Sarra Bouchelaghem Sourav Das Romen Singh Naorem Lilla Czuni Gbor Papp Marianna Kocsis 《Molecules (Basel, Switzerland)》2022,27(2)
Propolis is a natural bee product that is widely used in folk medicine. This study aimed to evaluate the antimicrobial and antibiofilm activities of ethanolic extract of propolis (EEP) on methicillin-resistant and sensitive Staphylococcus aureus (MRSA and MSSA). Propolis samples were collected from six regions in Hungary. The minimum inhibitory concentrations (MIC) values and the interaction of EEP-antibiotics were evaluated by the broth microdilution and the chequerboard broth microdilution methods, respectively. The effect of EEP on biofilm formation and eradication was estimated by crystal violet assay. Resazurin/propidium iodide dyes were applied for simultaneous quantification of cellular metabolic activities and dead cells in mature biofilms. The EEP1 sample showed the highest phenolic and flavonoid contents. The EEP1 successfully prevented the growth of planktonic cells of S. aureus (MIC value = 50 µg/mL). Synergistic interactions were shown after the co-exposition to EEP1 and vancomycin at 108 CFU/mL. The EEP1 effectively inhibited the biofilm formation and caused significant degradation of mature biofilms (50–200 µg/mL), as a consequence of the considerable decrement of metabolic activity. The EEP acts effectively as an antimicrobial and antibiofilm agent on S. aureus. Moreover, the simultaneous application of EEP and vancomycin could enhance their effect against MRSA infection. 相似文献
149.
Abstract— Anabaena doliolum , when exposed to either ultraviolet-B (UVB) radiation or Pb, showed reduced growth rate, carbon fixation, O2 -evolution, photosynthetic electron transport activity and ATP pool size. The rate of respiration was found to increase in UVB-treated cells; this increase was more pronounced in the cells exposed to UVB and Pb simultaneously. The UVB-induced inhibition of 2,6-dichlorophenol indophenol (DCPIP) photoreduction and lowering of chlorophyll a fluorescence could not be reversed by artificial electron donors (diphenyl carbazide, NH2 OH and MnCl2 ). These electron donors, however, substantially reversed the inhibition caused by Pb, thereby suggesting that UVB primarily inhibits the photosys-tem II (PS II) reaction center and Pb arrests the electron flow at the water splitting site. Nevertheless, the suppressed fluorescence intensity and the reduced emission and excitation peaks of phycobilisomes indicate the involvement of Pb in inhibition of PS II. All combinations of UVB and Pb inhibited the different metabolic processes in a synergistic manner. 相似文献
150.
Haldar B Mallick A Chattopadhyay N 《Journal of photochemistry and photobiology. B, Biology》2005,80(3):217-224
The photophysical behavior of a hydrophobically tailored water-soluble polymer, pyrene-end-capped poly(ethylene oxide) (PYPY), has been studied in aqueous buffered bovine serum albumin (BSA) and human serum albumin (HSA) media. In buffered aqueous solution the polymer shows dual emission corresponding to the monomer and the excimer of pyrene moiety. The relative intensity of the monomer to the excimer emission shows interesting variation with the addition of BSA and HSA and is indicative of significant interaction of these albumin proteins with the polymer. The binding interaction has been shown to have a prominent role on the steady state fluorescence anisotropy of the two emission bands. Attempt has been made to determine the micropolarities of the protein microenvironments from a comparison of the variation of the monomer to excimer relative fluorescence intensities of the probe in water–dioxane mixtures with varying composition. 相似文献