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31.
A variety of benzyl halides were converted to the corresponding aldehydes/ketones in respectable yields by IBX in DMSO at 65 °C. The bromohydrin reaction of olefins using NBS-H2O in DMSO can be nicely adapted to IBX-mediated oxidation of benzyl halides in such a way that olefins are converted to the corresponding 1,2-diketones in good isolated yields in one-pot. 相似文献
32.
Tapan Ghosh Srikanth Birudula Kalyan Jyoti Kalita Dr. Ratheesh K. Vijayaraghavan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(46):10501-10509
Control over the molecular packing in the solid state is of utmost importance in regulating the bulk optical properties of organic semiconductors. The electronic coupling between the molecules makes it possible to improve the properties of the bulk materials. This work reports an example of control over the selective formation of polymorphic single crystals of donor–acceptor-type small-molecule compound 25TR by 1) kinetic or 2) thermodynamic course of crystallisation to yield slipped stack (S) and cofacial (C) dimers in the single crystals. The distinct optical characteristics of the C-dimer and S-dimer are summarised. Both forms show significant excitonic interactions in the solid state, and the S-dimeric form has strong yellowish orange fluorescence, whereas the C-dimeric form is non-fluorescent in the crystalline state. DFT calculations and differential scanning calorimetric experiments revealed that the C-dimer polymorph is the thermodynamically stable form with a free energy offset of 0.43 eV in comparison with the S-dimer. Interestingly, the thermodynamically driven non-fluorescent single crystal was found to be convertible to its fluorescent form irreversibly by thermal trigger. The charge-carrier-transport characteristics of these two polymorphs were computed by using the Marcus–Hush formalism. The computations of the charge-carrier-transport behaviour revealed that the S-dimer ( 25TR(R) ) is ambipolar, whereas the C-dimer ( 25TR(Y) ) is predominantly n-type. 相似文献
33.
Applied Biochemistry and Biotechnology - The capacity of polystyrene microspheres with immobilized antibodies against type 1 pili ofE. coli was measured. Using pure IgG-type monoclonal antibodies... 相似文献
34.
35.
Rules of Boron–Nitrogen Doping in Defect Graphene Sheets: A First‐Principles Investigation of Band‐Gap Tuning and Oxygen Reduction Reaction Catalysis Capabilities 下载免费PDF全文
Introduction of defects and nitrogen doping are two of the most pursued methods to tailor the properties of graphene for better suitability to applications such as catalysis and energy conversion. Doping nitrogen atoms at defect sites of graphene and codoping them along with boron atoms can further increase the efficiency of such systems due to better stability of nitrogen at defect sites and stabilization provided by B?N bonding. Systematic exploration of the possible doping/codoping configurations reflecting defect regions of graphene presents a prevalent doping site for nitrogen‐rich BN clusters and they are also highly suitable for modulating (0.2–0.9 eV) the band gap of defect graphene. Such codoped systems perform significantly better than the platinum surface, undoped defect graphene, and the single nitrogen or boron atom doped defect graphene system for dioxygen adsorption. Significant stretching of the O?O bond indicates a lowering of the bond breakage barrier, which is advantageous for applications in the oxygen reduction reaction. 相似文献
36.
A variety of olefins have been shown to undergo conversion to the corresponding α-bromo/iodoketones when reacted with NBS/NIS and IBX in DMSO at room temperature. While the reaction is found to occur rapidly with e-rich arylolefins leading to the corresponding haloketones in 65-95% yields in 0.3-3.0 h, those containing e-withdrawing groups are found to yield diketones concomitantly, such that the latter are the exclusive products over extended duration of the reactions. 相似文献
37.
Here, we construct infinitely many number fields of any given degree d>1 whose class numbers have many prime factors. 相似文献
38.
Bahl and Zionts [H.C. Bahl, S. Zionts, A noniterative multiproduct multiperiod production planning method, Operations Research Letters 1 (1982) 219-221] formulated a problem for planning multiproduct multiperiod production on a single facility. They developed a column-minima noniterative method and claimed that it gave an optimal solution. We show that the claim is incorrect. 相似文献
39.
Ambarish Ray Dipankar Maity Anup Pramanik Kalyan K. Das Mahasweta Nandi Asim Bhaumik M. Nethaji Swastik Mondal Monika Mukherjee Mahammad Ali 《Polyhedron》2009,28(17):3659-3666
Two new copper(II) complexes, [Cu2(L1)2](ClO4)2 (1) and [Cu(L2)(ClO4)] (2), of the highly unsymmetrical tetradentate (N3O) Schiff base ligands HL1 and HL2 (where HL1 = N-(2-hydroxyacetophenone)-bis-3-aminopropylamine and HL2 = N-(salicyldehydine)-bis-3-aminopropylamine) have been synthesised using a template method. Their single crystal X-ray structures show that in complex 1 two independent copper(II) centers are doubly bridged through phenoxo-O atoms (O1A and O1B) of the two ligands and each copper atom is five-coordinated with a distorted square pyramidal geometry. The asymmetric unit of complex 2 consists of two crystallographically independent N-(salicylidene)-bis(aminopropyl)amine-copper(II) molecules, A and B, with similar square pyramidal geometries. Cryomagnetic susceptibility measurements (5–300 K) on complex 1 reveal a distinct antiferromagnetic interaction with J = ?23.6 cm?1, which is substantiated by a DFT calculation (J = ?27.6 cm?1) using the B3LYP functional. Complex 1, immobilized over highly ordered hexagonal mesoporous silica, shows moderate catalytic activity for the epoxidation of cyclohexene and styrene in the presence of TBHP as an oxidant. 相似文献
40.
Lauren M. Gehman Kalyan V. Vasudevan Rachel R. Butorac Salem S. Al-Deyab Alan H. Cowley 《Journal of chemical crystallography》2011,41(7):998-1001