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91.
92.
We report a calculation of the thermodynamic properties of an Ising system on a fractal lattice, the Sierpinski gasket (SG). The scale-invariant geometry of SG leads to a wider critical region compared to that in translationally invariant systems. We calculate exactly the near-neighbor correlation function and specific heat and discuss their critical behaviour. 相似文献
93.
Samraj Mollick Soumya Mukherjee Dongwook Kim Zhiwei Qiao Aamod V. Desai Rajat Saha Yogeshwar D. More Jianwen Jiang Myoung Soo Lah Sujit K. Ghosh 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(4):1053-1057
Metal–organic polyhedra (MOP) are a promising class of crystalline porous materials with multifarious potential applications. Although MOPs and metal–organic frameworks (MOFs) have similar potential in terms of their intrinsic porosities and physicochemical properties, the exploitation of carboxylate MOPs is still rudimentary because of the lack of systematic development addressing their chemical stability. Herein we describe the fabrication of chemically robust carboxylate MOPs via outer‐surface functionalization as an a priori methodology, to stabilize those MOPs system where metal–ligand bond is not so strong. Fine‐tuning of hydrophobic shielding is key to attaining chemical inertness with retention of the framework integrity over a wide range of pH values, in strong acidic conditions, and in oxidizing and reducing media. These results are further corroborated by molecular modelling studies. Owing to the unprecedented transition from instability to a chemically ultra‐stable regime using a rapid ambient‐temperature gram‐scale synthesis (within seconds), a prototype strategy towards chemically stable MOPs is reported. 相似文献
94.
Anil K. Gupta Xiaopeng Yin Munmun Mukherjee Aman A. Desai Aliakbar Mohammadlou Kelsee Jurewicz William D. Wulff 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(11):3399-3405
A highly diastereo‐ and enantioselective method for the epoxidation of aldehydes with α‐diazoacetamides has been developed with two different borate ester catalysts of VANOL. Both catalytic systems are general for aromatic, aliphatic, and acetylenic aldehydes, giving high yields and inductions for nearly all cases. One borate ester catalyst has two molecules of VANOL and the other only one VANOL. Catalysts generated from BINOL and VAPOL are ineffective catalysts. An application is shown for access to the side‐chain of taxol. 相似文献
95.
The powder diffractometer and Hi-Q diffractometer at Dhruva reactor make use of five identical 1-D position sensitive detectors (PSDs) to scan scattering angles in the range 3° to 140°. In order to improve the overall throughput of these spectrometers, it is planned to install a bank of 15 high-efficiency and high-resolution PSDs arranged in three layers with five PSDs in each layer. With each high pressure PSD (3He 10 bar + Kr 2 bar) showing the efficiency gain of 1.8 at 1.2 Å, detector bank is expected to show overall gain of 5.5 times the present detection efficiency and reduction in data collection time by equivalent factor. The 1-D PSDs are developed in batches of five, and are characterized so that all PSDs operate at uniform parameters such as position resolution, uniformity of efficiency and linearity of response. Position spectrum indicates the differential position resolution to be ~1 mm and integral position resolution to be 3–4 mm. Broadening of position spectrum at the extreme end of sensitive length of PSD is analysed using fine shift of the beam. Dependence of position resolution and dynamic range of output pulse on the input impedance of pre-amplifier is also presented. 相似文献
96.
97.
Akshat M. Desai Dr. Prabhat K. Singh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(8):2035-2042
Devising sensors for the perrhenate anion in aqueous media is extremely challenging, and has seldom been reported in the literature. Herein, we report a fluorescence turn-on sensor for the perrhenate anion in aqueous media based on the aggregation-induced emission of a popular ultrafast molecular rotor dye, Thioflavin-T. The selective response towards the perrhenate anion has been rationalized in terms of matching water affinity, with the weakly hydrated perrhenate anion spontaneously forming a contact ion pair with the weakly hydrated ultrafast molecule-rotor-based organic cation, Thioflavin-T, which in turn leads to an aggregate assembly that provides a fluorescence turn-on response towards perrhenate. The sensing response of Thioflavin-T has been found to be quite selective towards the perrhenate anion when tested against anions that are ubiquitously present in the environment, such as chloride, nitrate, and sulfate anions. The formation of self-assembled Thioflavin-T aggregates has also been investigated by time-resolved emission and temperature-dependent measurements. 相似文献
98.
RajnikantEmail author Dinesh Kamni M.?B.?Deshmukh S.?S.?Jagpat S.?R.?Desai 《Journal of chemical crystallography》2005,35(4):293-296
The title compound crystallizes in the monoclinic space group P21/n with unit cell parameters a = 10.842(9), b = 5.750(7), c = 12.964(6) Å, = 110.13(6), V = 758.8(11) Å3 and Z = 4. The final reliability index is 0.060 for 1034 observed reflections. The five-membered heterocyclic thiazole ring is coplanar with its fused benzene ring. The crystal structure is stabilized by two intermolecular N=H s N hydrogen bonded interactions. 相似文献
99.
Supriya S. Khot Prashant V. Anbhule Uday V. Desai Prakash P. Wadgaonkar 《Comptes Rendus Chimie》2018,21(9):814-821
Tris-hydroxymethylaminomethane has been demonstrated to be an efficient organocatalyst in diversity-oriented synthesis of medicinally prevalent spirochromenes by one-pot, three-component reactions between isatins, malononitrile, and enolizable CH acids like dimedone, 4-hydroxycoumarin, 4-hydroxy-N-methylquinolin-2-one, or in situ generated 2-methylpyrazolon-2-one. Biodegradability and extremely low cost of the catalyst are the noteworthy features of this chromatography-free protocol. 相似文献
100.
2-Amino-4-(coumarin-3-yl)-thiazole (1) reacted with acetyl chloride gives compound (2) which on further refluxed with various aromatic aldehydes gives compound (3a-j). Thus obtained (3a-j) on further condensed with NH4OH.HCl using NaOH as a catalyst afforded isoxazoles (4a-j). All the synthesized compounds characterized on the basis of the IR, 1H NMR, 13C NMR and elemental analysis. All the compounds have been screened for antibacterial activity against bacteria (Gram + ve) & (Gram ? ve) and antifungal activity. 相似文献