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131.
Cheng-Zong Kuo Li-Yun Hsu Yu-Shan Chen Dr. Kenta Goto Dr. Subhendu Maity Dr. Yi-Hung Liu Prof. Shie-Ming Peng Dr. Kien Voon Kong Prof. Teruo Shinmyozu Prof. Jye-Shane Yang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(50):11511-11521
Anthracene–pentiptycene hybrid systems 1-Cn , where n refers to the number of carbon atoms in the linear alkyl chain, crystallize in three different polymorphs, denoted Y (yellow), G (green), and B (blue) forms in terms of the fluorescence color. While all Y-form crystals show the same yellow-to-blue fluorescence color response to the photomechanical stress generated by the anthracene [4+4] photodimerization reaction, the four G forms exhibit distinct photomechanofluorochromism (PMFC): from green to blue for G-1-C4 , to orange for G-1-C7 , to red for G-1-C8 , and to red then blue for G-1-C9 , and the B forms show no photochromic activity. The intriguing RGB three-color PMFC and abnormal topochemical reactivity of G-1-C9 are attributed to inherent softness of the crystal lattice. 相似文献
132.
Rajesh Belgamwar Ayan Maity Tisita Das Sudip Chakraborty Chathakudath P. Vinod Vivek Polshettiwar 《Chemical science》2021,12(13):4825
An excessive amount of CO2 is the leading cause of climate change, and hence, its reduction in the Earth''s atmosphere is critical to stop further degradation of the environment. Although a large body of work has been carried out for post-combustion low-temperature CO2 capture, there are very few high temperature pre-combustion CO2 capture processes. Lithium silicate (Li4SiO4), one of the best known high-temperature CO2 capture sorbents, has two main challenges, moderate capture kinetics and poor sorbent stability. In this work, we have designed and synthesized lithium silicate nanosheets (LSNs), which showed high CO2 capture capacity (35.3 wt% CO2 capture using 60% CO2 feed gas, close to the theoretical value) with ultra-fast kinetics and enhanced stability at 650 °C. Due to the nanosheet morphology of the LSNs, they provided a good external surface for CO2 adsorption at every Li-site, yielding excellent CO2 capture capacity. The nanosheet morphology of the LSNs allowed efficient CO2 diffusion to ensure reaction with the entire sheet as well as providing extremely fast CO2 capture kinetics (0.22 g g−1 min−1). Conventional lithium silicates are known to rapidly lose their capture capacity and kinetics within the first few cycles due to thick carbonate shell formation and also due to the sintering of sorbent particles; however, the LSNs were stable for at least 200 cycles without any loss in their capture capacity or kinetics. The LSNs neither formed a carbonate shell nor underwent sintering, allowing efficient adsorption–desorption cycling. We also proposed a new mechanism, a mixed-phase model, to explain the unique CO2 capture behavior of the LSNs, using detailed (i) kinetics experiments for both adsorption and desorption steps, (ii) in situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy measurements, (iii) depth-profiling X-ray photoelectron spectroscopy (XPS) of the sorbent after CO2 capture and (iv) theoretical investigation through systematic electronic structure calculations within the framework of density functional theory (DFT) formalism.Capturing CO2 before its release. Lithium silicate nanosheets showed high CO2 capture capacity (35.3 wt%) with ultra-fast kinetics (0.22 g g−1 min−1) and enhanced stability at 650 °C for at least 200 cycles, due to mixed-phase-model of CO2 capture. 相似文献
133.
Sardar PS Samanta S Maity SS Dasgupta S Ghosh S 《The journal of physical chemistry. B》2008,112(11):3451-3461
The steady-state and time-resolved studies of the sensitized emission of the excited-state proton transfer (ESIPT) probe 3-hydroxy-2-naphthoic acid (3HNA) when bound to bovine serum albumin (BSA) and human serum albumin (HSA) indicate that the nonradiative dipole-dipole F?rster type energy transfer from Trp singlet state of proteins to the ESIPT singlet state of 3HNA is greater in the case of HSA. This is supported by the distance and the orientation of the donor-acceptor pair obtained from the protein-ligand docking studies. The docking studies of the complex of BSA-3HNA also indicate that Trp 134 rather than Trp 213 is involved in the energy transfer process. The local environment of Trp 134 in BSA rather than that of Trp 213 is perturbed because of interaction with 3HNA as revealed by the optical resolution of Trp 134 phosphorescence in the complex at 77 K. Docking studies support the larger rotational correlation time, thetac (approximately 50 ns), observed for Trp residue/residues in the complexes of HSA and BSA compared with that in the free proteins. 相似文献
134.
Santu Maity Dr. Krishnendu Aich Chandraday Prodhan Prof. Keya Chaudhuri Dr. Ajoy Kumar Pramanik Prof. Siddhartha Das Dr. Jhuma Ganguly 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(18):4856-4863
In the present study, the carbazole and 2,3,3-triphenylacrylonitrile (TPAN) nanostructures (2-CTPAN and 2,2′-CTPAN) have been designed and synthesized by Pd-catalyzed Sonogashira cross-coupling reaction. CTPAN exhibit aggregation-induced emission enhancement (AIEE) behavior in water with high fluorescence quantum yield. Both the compounds show tunable self-assembly in water as well as in N,N-dimethylformamide (DMF) by extended π–π stacking interactions. CTPAN can be self-assembled into spherical particles in water and the structures of these self-assemblies have been investigated using X-ray diffraction. Interestingly, 2-CTPAN and 2,2′-CTPAN form organogels with a critical gelation concentration (CGC) of 11 and 15 mg mL−1, respectively, in DMF and exhibit acicular and rod shaped morphology, respectively. The single-crystal structure of 2-CTPAN shows that the intermolecular C−H⋅⋅⋅π interactions lock the molecular conformation into a staircase-shaped supramolecular assembly. These AIEE active compounds reveal high water dispersibility, strong yellow fluorescence with high quantum yield, promising photostability and excellent biocompatibility, which make them potential bioimaging agents. 相似文献
135.
D. Maity S. SenGupta S. Sur 《The European Physical Journal C - Particles and Fields》2005,42(4):453-460
In this work we explore the geodesic deviations of spinning test particles in a string inspired Einstein-Kalb-Ramond background. Such a background is known to be equivalent to a spacetime geometry with torsion. We have shown here that the antisymmetric Kalb-Ramond field has a significant effect on the geodesic deviation of a spinning test particle. A search for observational evidence of such an effect in astrophysical experiments may lead to a better understanding of the geometry of the background spacetime.Received: 5 April 2005, Revised: 19 May 2005, Published online: 8 July 2005 相似文献
136.
Methyl methacrylate (MMA) was polymerized at 40 in the presence of dimethyl formamide (DMF), using cetyl trimethyl ammonium bromide with benzoyl peroxide (CTABBZ2O2) as the initiating system. At high dilutions the rate of polymerization was proportional to (initiator)1–2. In near-bulk conditions using low [DMF], the rate was practically independent of [BZ2O2], while the kinetic order with respect to CTAB was about 0.16. The polymerization was inhibited by hydroquinone. A radical mechanism is suggested for the polymerization with primary radical termination significant in near-bulk systems and bimolecular termination significant for high dilution with DMF. Effects of various other solvents or additives on the polymerization were examined. DMF, acetonitrile and pyridine act as rate accelerating diluents; benzene, methanol, chloroform and acetone as inert diluents; formamide and acetamide cause pronounced retardation. 相似文献
137.
Vertical detachment energies (VDE) and UV/Vis absorption spectra of hydrated carbonate radical anion clusters, CO3.?.n H2O (n=1–8), are determined by means of ab initio electronic structure theory. The VDE values of the hydrated clusters are calculated with second‐order Moller–Plesset perturbation (MP2) and coupled cluster theory using the 6‐311++G(d,p) set of basis functions. The bulk VDE value of an aqueous carbonate radical anion solution is predicted to be 10.6 eV from the calculated weighted average VDE values of the CO3.?.n H2O clusters. UV/Vis absorption spectra of the hydrated clusters are calculated by means of time‐dependent density functional theory using the Becke three‐parameter nonlocal exchange and the Lee–Yang–Parr nonlocal correlation functional (B3LYP). The simulated UV/Vis spectrum of the CO3.?.8 H2O cluster is in excellent agreement with the reported experimental spectrum for CO3.? (aq), obtained based on pulse radiolysis experiments. 相似文献
138.
Shyamaprosad Goswami Manas Kumar Das Annada C. Maity Ching Kheng Quah Hoong-Kun Fun 《合成通讯》2016,46(18):1529-1536
The first syntheses of indolopterin and indoloquinoxaline, two important and dissimilar diheterocycles linking C-2 of indole with C-6 of pterin (significant positions for showing biological activity), and quinoxaline, respectively, have been achieved based on two classical reactions. The introduction of a keto methyl group on to the 6-position of pterin and quinoxaline followed by Fischer indole synthesis led to these target diheterocycles. These indole-substituted diheterocycles will significantly increase the electron density on the pterin-5-N and quinoxazoline-2-N, which may change the redox properties of pterin and quinoxaline, and also the electron-withdrawing pterin or quinoxazoline should make the indole NH more acidic. 相似文献
139.
Dey D Bose A Bhattacharyya D Basu S Maity SS Ghosh S 《The journal of physical chemistry. A》2007,111(42):10500-10506
A derivative of phenazine, dibenzo[a,c]phenazine (DBPZ), can be used as a very good hydrogen-bonding probe unlike its parent phenazine molecule. Steady-state absorption and fluorescence studies reveal that DBPZ is completely insensitive to polarity of the medium. However, DBPZ can form a hydrogen bond very efficiently in its first excited singlet state. The extent of this excited-state hydrogen-bond formation depends both on size and on hydrogen-bond donor ability of the solvents. Time-resolved fluorescence studies and theoretical calculations also suggest that this hydrogen-bond formation is much more favorable in the excited state as compared to the ground state. In the excited state, the electron density is pushed toward the nitrogen atoms from the benzene rings, thereby increasing the dipole moment of the DBPZ molecule. Although the dipole moment of DBPZ increases upon photoexcitation, like other polarity probes, the molecule remains fully insensitive to the polarity of the interacting solvent. This unusual behavior of DBPZ as compared to simple phenazine and other polarity probes is due to the structure of the molecule. Hydrogen atoms at the 1 and 8 positions of DBPZ are sterically interacting with a lone pair of electrons on the proximate nitrogen atoms and make both of the nitrogen atoms inaccessible to solvent molecules. For this reason, DBPZ cannot sense the polarity of the medium. However, DBPZ can only sense solvents, those that have hydrogen with some electropositive nature, that is, the hydrogen-bond donating solvents. Hydrogen being the smallest among all elements can only interact with the lone pair of electrons of nitrogen atoms. Thus, DBPZ can act as a sensor for the hydrogen-bond donating solvents irrespective of their dielectrics. 相似文献
140.
Dr. Simli Dey Dr. Dayana Surendran Dr. Oskar Engberg Ankur Gupta Dr. Sashaina E. Fanibunda Anirban Das Dr. Barun Kumar Maity Arpan Dey Vicky Visvakarma Mamata Kallianpur Dr. Holger A. Scheidt Prof. Dr. Gilbert Walker Prof. Dr. Vidita A. Vaidya Prof. Dr. Daniel Huster Prof. Dr. Sudipta Maiti 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(27):7533-7541
Serotonin, an important signaling molecule in humans, has an unexpectedly high lipid membrane affinity. The significance of this finding has evoked considerable speculation. Here we show that membrane binding by serotonin can directly modulate membrane properties and cellular function, providing an activity pathway completely independent of serotonin receptors. Atomic force microscopy shows that serotonin makes artificial lipid bilayers softer, and induces nucleation of liquid disordered domains inside the raft-like liquid-ordered domains. Solid-state NMR spectroscopy corroborates this data at the atomic level, revealing a homogeneous decrease in the order parameter of the lipid chains in the presence of serotonin. In the RN46A immortalized serotonergic neuronal cell line, extracellular serotonin enhances transferrin receptor endocytosis, even in the presence of broad-spectrum serotonin receptor and transporter inhibitors. Similarly, it increases the membrane binding and internalization of oligomeric peptides. Our results uncover a mode of serotonin–membrane interaction that can potentiate key cellular processes in a receptor-independent fashion. 相似文献