排序方式: 共有89条查询结果,搜索用时 46 毫秒
31.
Majeed Z Mondal KC Kostakis GE Lan Y Anson CE Powell AK 《Dalton transactions (Cambridge, England : 2003)》2010,39(20):4740-4743
Using glycerol (H?gly) as a primary ligand, the decanuclear aggregate [Mn(II)?Mn(III)?Dy?(μ?-OH)?(Hgly)?(H?gly)?-(PhCO?)??(H?O)?]·10CH?CN (1) has been synthesised; it has a structure built up from two Mn?Dy? heterocubane units linked through a central Dy?(μ-benzoate)? paddle-wheel dimer and shows slow relaxation of its magnetisation. 相似文献
32.
Dr. Kartik Chandra Mondal Dr. Sudipta Roy Dr. Susmita De Dr. Pattiyil Parameswaran Dr. Birger Dittrich Dr. Fabian Ehret Prof. Dr. Wolfgang Kaim Prof. Dr. Herbert W. Roesky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(37):11646-11649
Compound (Me2‐cAAC:)2Co0 ( 2 ; Me2‐cAAC:=cyclic (alkyl) amino carbene; :C(CH2)(CMe2)2N‐2,6‐iPr2C6H3) was synthesized by the reduction of the precursor (Me2‐cAAC:)2CoICl ( 1 ) with KC8 in THF. The cyclic voltammogram of 1 exhibited one‐electron reduction, which suggests that synthesis of a bent 2‐metallaallene ( 2 ) from 1 should be possible. Compound 2 contains one cobalt atom in the formal oxidation state zero, which is stabilized by two Me2‐cAAC: ligands. Bond lengths from X‐ray diffraction are 1.871(2) and 1.877(2) Å with a C‐Co‐C bond angle of 170.12(8)°. The EPR spectrum of 2 exhibited a broad resonance attributed to the unique quasi‐linear structure, which favors near degeneracy and gives rise to very rapid relaxation conditions. The cAAC?Co bond in 2 can be considered as a typical Dewar–Chatt–Duncanson type of bonding, which in turn retains 2.5 electron pairs on the Co atom as nonbonding electrons. 相似文献
33.
Yan Li Dr. Kartik Chandra Mondal Dr. Prinson P. Samuel Prof. Dr. Hongping Zhu Claudia M. Orben Dr. Saravanan Panneerselvam Priv.‐Doz. Dr. Birger Dittrich Dr. Brigitte Schwederski Prof. Dr. Wolfgang Kaim Totan Mondal Dr. Debasis Koley Prof. Dr. Herbert W. Roesky 《Angewandte Chemie (International ed. in English)》2014,53(16):4168-4172
A neutral C4 cumulene 1 that includes a cyclic alkyl(amino) carbene (cAAC), its air‐stable radical cation 1 .+, and dication 1 2+ have been synthesized. The redox property of 1 .+ was studied by cyclic voltammetry. EPR and theoretical calculations show that the unpaired electron in 1 .+ is mainly delocalized over the central C4 backbone. The commercially available CBr4 is utilized as a source of dicarbon in the cumulene synthesis. 相似文献
34.
35.
Dhansay Dewangan Kartik Nakhate Achal Mishra Alok Singh Thakur Harish Rajak Jaya Dwivedi Swapnil Sharma Sarvesh Paliwal 《Journal of heterocyclic chemistry》2019,56(2):566-578
A series of quinoxalinone derivatives were synthesized by the reaction of o‐phenylenediamine with oxalic acid to yield 1, 4‐dihydro quinoxaline‐2, 3‐dione ( 1 ) and then treated with thionyl chloride to yield 2, 3 dichloro quinoxaline ( 2 ). This was further reacted with hydrazine hydrate to produce 2, 3‐dihydrazinyl quinoxaline ( 3 ). This was finally reacted with substituted aromatic aldehydes to produce 2,3‐bis[2‐(sustituted benzylidine) hydrazinyl] quinoxalines ( 4 ). These quinoxalinone derivatives were characterized by infrared spectroscopy and nuclear magnetic resonance spectroscopy and MASS spectral data. All the synthesized compounds were evaluated for their antimicrobial activity. The results of the antimicrobial study revealed that compounds 4c , 4d , and 4i were active and exhibited better inhibitory activities as compared to standard drug ciprofloxacin. The results were further checked with protein legend interaction by using docking studies, and all the compounds exhibited good docking scores between ?8.72 and ?11.29 kcal/mol against dihydrofolate reductase protein fragment from Staphylococcus aureus (PDB ID‐4XE6). Among all compound, 4c has shown maximum docking score and found in agreement to in vitro studies. 相似文献
36.
37.
S. Bhattacharyya S. G. Nakhate 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,55(1):9-15
We have observed superfluorescence (SF) on five atomic transitions at
visible wavelengths 633.58, 635.00, 640.09, 640.61 and 736.22 nm in Doppler
broadened gas of europium (Eu) atom. The nanosecond SF pulses were observed
by longitudinally pumping Eu vapor column with a pulsed dye laser to upper
states 4f65d6s2, 8D7/2at 346.79 nm and 4f75d6p,
10F5/2at 348.73 nm from the ground state 4f76s2,
8S7/2. High optical conversion efficiency ≈10% was
measured for these SF transitions. Our experiment deals with the large
sample multilevel SF in the regime where the length of the excited
column L is greater than the maximum value of the Arecchi-Courtens
length (Lc). The observed variation of SF peak intensity (Ifl) and time
delay for SF evolution (τD) with number of atoms in the excited
state (N) resemble theoretically predicted SF scaling laws for transverse
excitation, namely Ifl∝N and tD μ 1/?N\tau_D \propto 1/{\sqrt N} although the experimental condition
is similar to the swept excitation. This could be due to the Rabi frequency
associated with the pump transition which is comparable to the SF delay time
precluding the initiation of SF at different times along the sample and
results in transverse (instantaneous) excitation. The experimental τD
values were found to be in agreement with the quantum mechanical
calculations describing SF. 相似文献
38.
Kartik Prasanna 《Inventiones Mathematicae》2009,176(3):521-600
We prove that the theta correspondence for the dual pair , for B an indefinite quaternion algebra over ℚ, acting on modular forms of odd square-free level, preserves rationality and p-integrality in both directions. As a consequence, we deduce the rationality of certain period ratios of modular forms and
even p-integrality of these ratios under the assumption that p does not divide a certain L-value. The rationality is applied to give a direct construction of isogenies between new quotients of Jacobians of Shimura
curves, completely independent of Faltings’ isogeny theorem.
To my parents. 相似文献
39.
Anilkumar S. Patel Satishkumar D. Tala Pankajkumar B. Nariya Kartik D. Ladva Naval P. Kapuriya 《中国化学会会志》2019,66(3):247-252
Triethanolamine (TEOA), an inexpensive and eco‐friendly base, was used to efficiently catalyze the three‐component condensation reaction of heterocyclic/aromatic aldehyde, (α/β)‐naphthol, and malononitrile in water to give the corresponding substituted 2‐amino‐4H‐chromene derivatives with excellent yields. 相似文献
40.
Niharika Mohapatra Kartik K. Iyer B.A. Chalke E.V. Sampathkumaran 《Solid State Communications》2009,149(39-40):1641-1645
We have investigated the magnetic behavior of nano crystals, synthesized by high-energy ball-milling, for a well-known geometrically frustrated spin-chain system, Ca3CoRhO6, and compared its magnetic characteristics with those of the bulk form by measuring ac and dc magnetization. The features attributable to the onset of ‘partially disordered antiferromagnetism’ (characterizing the bulk form) are not seen in the magnetization data of the nano particles; the magnetic moment at high fields in the very low temperature range in the magnetically ordered state gets relatively enhanced in the nano particles. It appears that the ferromagnetic intrachain interaction, judged by the sign of the paramagnetic Curie temperature, is preserved in the nano particles. These trends are opposite to those seen in the nano particles of Ca3Co2O6. However, the complex spin-dynamics as evidenced by large frequency dependence of ac susceptibility is retained in the nano particles as well. Thus, there are some similarities and dissimilarities between the properties of the nano particles and those of the bulk. We believe that these findings will be useful to understand correlation lengths deciding various properties of geometrical frustration and/or spin-chain phenomena. 相似文献