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101.
Purva Chibde Dr. Ravindra K. Raut Vikas Kumar Rahul Deb Dr. Rajesh Gonnade Dr. Moumita Majumdar 《化学:亚洲杂志》2021,16(15):2118-2125
The intramolecularly double-donor-stabilized stannylene 1 has been synthesized from the salt-metathesis reaction between two equivalents of lithium pyridine ene-amide L1 and SnCl2. Compound 1 exhibits dipolar behavior when reacted with B(C6F5)3 leading to the zwitterionic compound 2 . The reaction of 1 with one equivalent and 0.5 equivalent of AgOTf (OTf=trifluoromethane sulfonate) result in the formation of a stannylene-AgOTf complex 3 and a homoleptic distannylene-silver ionic complex 4 , respectively. Analogous to complex 4 , the gold(I) complex 5 has been synthesized from the reaction between two equivalents of 1 and 0.5 equivalent of AuCl.SMe2/Me3SiOTf. Complex 5 is the first example of homoleptic stannylene-Au(I) ionic complex among the very scarce reports on stannylene-gold(I) coordination complexes. All compounds have been structurally characterized using single crystal X-ray crystallography. Solution-state characterization have been performed using multinuclear NMR techniques. Detailed DFT calculations on the optimized geometries 1 o , 3 o – 5 o reveal the change in sp- hybridization on the pyramidal Sn(II) center upon metal coordination and their bonding overlaps. 相似文献
102.
Moumita Koley Laurin Wimmer Michael Schnürch Marko D. Mihovilovic 《Journal of heterocyclic chemistry》2013,50(6):1368-1373
The first example of a Liebeskind–Srogl cross‐coupling reaction in water as sole reaction solvent is reported. 2‐(Methylthio)pyridine and 2‐(methylthio)benzothiazole were reacted in the presence of a Pd(0) catalyst and copper(I) thiophene‐2‐carboxylate with a series of arylboronic acids. These cross coupling reactions in water proceeded well with electron‐rich boronic acids and gave comparable yields to literature examples using organic solvents. Electron‐poor boronic acids gave somewhat lower yields in aqueous medium. 相似文献
103.
The Group 15 Pn(I) cations (Pn=N, P, As, Sb and Bi), which are isoelectronic with the donor-stabilized carbones, have emerged recently. Despite the presence of two lone pair of electrons, the Pn(I) cations are weakly nucleophilic due to their inherent positive charge. Strongly electron-donating supporting ligands including zwitterionic forms have been used to enhance their Lewis basicity. Furthermore, the chelating effect of cyclic ligand systems proved effective in increasing their nucleophilicity. The strategies involved in successfully isolating the fleeting Sb(I) and Bi(I) cations as the recent most achievements in this field have been discussed. The syntheses, structure, bonding situations and reactivity of the Pn(I) cations are discussed. An outlook on the periodic trends and future applications of these electronically unique electron-rich cationic moieties have been provided. 相似文献
104.
Moumita Singha Roy Xiaofeng Meng Karuna Koda Sivappa Rasapalli Delphine Gout Carl J. Lovely 《Tetrahedron letters》2019,60(14):979-982
Asymmetric total synthesis of the imidazole containing β-carboline natural product, haploscleridamine, from histidine is described. Key to the successful assembly of this alkaloid is a ring-closing metathesis reaction of an imidazole derived allylic alcohol to construct a 3-piperidinone. Application of the Buchwald-modification of the classical Fischer indolization and deprotection of the N-tosyl moiety delivered haploscleridamine. 相似文献
105.
No-carrier-added (nca) 208,209,210At was produced for the first time from 9Be induced reaction on thallium carbonate target at BARC-TIFR pelletron, Mumbai, India. The target of 4 mg/cm2 thickness was prepared by centrifugation technique. Nca At was separated from the thallium target by liquid–liquid extraction
using liquid cation exchanger HDEHP dissolved in cyclohexane and liquor ammonia. 相似文献
106.
Novel azobenzene based bispropargyl sulfones have been prepared in the thermally stable E-form: irradiation with a high-pressure Hg lamp converted them to the Z-isomer which showed higher DNA-cleaving efficiency. 相似文献
107.
The nature of interactions between ethanol and carbon dioxide has been characterized using simulations via the Car-Parrinello molecular dynamics (CPMD) method. Optimized geometries and energetics of free-standing ethanol-CO2 clusters exhibit evidence for a relatively more stable electron donor-acceptor (EDA) complex between these two species rather than a hydrogen-bonded configuration. This fact has also been confirmed by the higher formation rate of the EDA complex in supercritical carbon dioxide-ethanol mixtures. The probability density distribution of CO2 molecules around ethanol in the supercritical state shows two high probability regions along the direction of the lone pairs on the oxygen atom of ethanol. The EDA interaction between ethanol and CO2 as well as that between CO2 molecules themselves leads to significant deviations from linearity in the geometry of the CO2 molecule. The vibrational spectra of carbon dioxide obtained from the atomic velocity correlation functions in the bulk system as well as from isolated complexes show splitting of the nu2 bending mode that arises largely from CO2-CO2 interactions, with ethanol contributing only marginally because of its low concentration in the present study. The stretching frequency of the hydroxyl group of ethanol is shifted to lower frequencies in the bulk mixture when compared to its gas-phase value, in agreement with experiments. 相似文献
108.
We analyze the stationary state properties of an atomic Bose-Einstein condensate coupled to a molecular condensate via a Raman photoassociation process using Gross-Pitaevskii and modified Gross-Pitaevskii model and compare the results. We find
that the static properties depend crucially on the Raman detuning parameter, which can be experimentally varied. We also show
how the analytical expressions for densities of atoms and molecules of the hybrid system can be found in the Thomas-Fermi
approximation where kinetic energies are not included. We have explored the feasibility of maximum molecular BEC formation
by varying the Raman detuning. 相似文献
109.
Moumita Pait Gargi Kundu Srinu Tothadi Suvendu Karak Shailja Jain Kumar Vanka Sakya S. Sen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(9):2830-2834
The reaction of SIPr, [1,3‐bis(2,6‐diisopropylphenyl)‐imidazolin‐2‐ylidene] ( 1 ), with C6F6 led to the formation of an unprecedented mesoionic compound ( 2 ). The formation of 2 is made accessible by deprotonation of the SIPr backbone with simultaneous elimination of HF. The C?F bond para to the imidazolium ring in 2 is only of 1.258(4) Å, which is the one of the shortest structurally authenticated C?F bonds known to date. The liberation of HF during the reaction is unequivocally proved by the addition of one more equivalent of SIPr, which leads to the imidazolium salt with the HF2? anion. To functionalize 2 , the latter reacted with B(C6F5)3 to give an unusual donor–acceptor compound, where the fluoride atom from the C6F5 moiety coordinates to B(C6F5)3 and the carbanion moiety remains unaffected. Such coordination susceptibility of the fluoride atom of a nonmetallic system to a main‐group Lewis acid (Fnon‐metal→BR3) is quite unprecedented. 相似文献
110.
Possibilities of generation of lower order and higher order intermodal entanglement in four‐wave mixing (FWM) process are rigorously investigated using Sen‐Mandal perturbative technique. The investigation has revealed that for a set of experimentally realizable parameters, one can observe lower order and higher order intermodal entanglement between pump and signal modes and signal and idler modes in a FWM process. In addition, trimodal entanglement involving pump, signal and idler modes is also reported. 相似文献