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191.
Corrigendum: Triazole‐Tailored Guanosine Dinucleosides as Biomimetic Ion Channels to Modulate Transmembrane Potential
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Observation of Slow Relaxation and Single‐Molecule Toroidal Behavior in a Family of Butterfly‐Shaped Ln4 Complexes
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Sourav Biswas Dr. Sourav Das Tulika Gupta Dr. Saurabh Kumar Singh Dr. Michael Pissas Dr. Gopalan Rajaraman Prof. Vadapalli Chandrasekhar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18532-18550
A family of five isostructural butterfly complexes with a tetranuclear [Ln4] core of the general formula [Ln4(LH)2(μ2‐η1η1Piv)(η2‐Piv)(μ3‐OH)2]?x H2O?y MeOH?z CHCl3 ( 1 : Ln=DyIII, x=2, y=2, z=0; 2 : Ln=TbIII, x=0, y=0, z=6; 3 : Ln=ErIII, x=2, y=2, z=0; 4 : Ln=HoIII, x=2, y=2, z=0; 5 : Ln=YbIII, x=2, y=2, z=0; LH4=6‐{[bis(2‐hydroxyethyl)amino]methyl}‐N′‐(2‐hydroxy‐3‐methoxybenzylidene)picolinohydrazide; PivH=pivalic acid) was isolated and characterized both structurally and magnetically. Complexes 1 – 5 were probed by direct and alternating current (dc and ac) magnetic susceptibility measurements and, except for 1 , they did not display single‐molecule magnetism (SMM) behavior. The ac magnetic susceptibility measurements show frequency‐dependent out‐of‐phase signals with one relaxation process for complex 1 and the estimated effective energy barrier for the relaxation process was found to be 49 K. We have carried out extensive ab initio (CASSCF+RASSI‐SO+SINGLE_ANISO+POLY_ANISO) calculations on all the five complexes to gain deeper insights into the nature of magnetic anisotropy and the presence and absence of slow relaxation in these complexes. Our calculations yield three different exchange coupling for these Ln4 complexes and all the extracted J values are found to be weakly ferro/antiferromagentic in nature (J1=+2.35, J2=?0.58, and J3=?0.29 cm?1 for 1 ; J1=+0.45, J2=?0.68, and J3=?0.29 cm?1 for 2 ; J1=+0.03, J2=?0.98, and J3=?0.19 cm?1 for 3 ; J1=+4.15, J2=?0.23, and J3=?0.54 cm?1 for 4 and J1=+0.15, J2=?0.28, and J3=?1.18 cm?1 for 5 ). Our calculations reveal the presence of very large mixed toroidal moment in complex 1 and this is essentially due to the specific exchange topology present in this cluster. Our calculations also suggest presence of single‐molecule toroics (SMTs) in complex 2 . For complexes 3 – 5 on the other hand, the transverse anisotropy was computed to be large, leading to the absence of slow relaxation of magnetization. As the magnetic field produced by SMTs decays faster than the normal spin moments, the concept of SMTs can be exploited to build qubits in which less interference and dense packing are possible. Our systematic study on these series of Ln4 complexes suggest how the ligand design can help to bring forth such SMT characteristics in lanthanide complexes. 相似文献
196.
The naturally occurring dienamides, piperine, piperlonguminine, guineensine, brachystamide-B and pergumidiene were converted to the corresponding β, γ-unsaturated amides by using Mg/MeOH. 相似文献
197.
Structural Chemistry - The role of Ti(II) sandwich complex, [Cp2Ti], generated by the combination of [Cp2TiCl2] and two equivalents of nBuLi, in situ, in toluene has been investigated theoretically... 相似文献
198.
Basak Anirban Sadhu Arindam Das Kunal Sharma Kapil K. 《International Journal of Theoretical Physics》2019,58(9):3158-3179
In this paper, an attempt is made to present a method of quantum cost minimization or optimization technique for quantum reversible circuits using proposed merger rules in Exclusive Sum of Product (ESOP) method. These modified ESOP methods are used to minimize the quantum circuits. We found that the quantum cost is drastically decreased than the previous ESOP method. It will be easy to find the quantum cost and quantum gate optimized quantum circuits implementation. It will also reduce quantum error while the quantum circuit is executed in real quantum processor.
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Narayan Das Soumen De Nantu Sarkar 《Mathematical Methods in the Applied Sciences》2020,43(3):1313-1336
The generalized thermoelasticity theory based upon the Green and Naghdi model III of thermoelasticity as well as the Eringen's nonlocal elasticity model is used to study the propagation of harmonic plane waves in a nonlocal thermoelastic medium. We found two sets of coupled longitudinal waves, which are dispersive in nature and experience attenuation. In addition to the coupled waves, there also exists one independent vertically shear-type wave, which is dispersive but experiences no attenuation. All these waves are found to be influenced by the elastic nonlocality parameter. Furthermore, the shear-type wave is found to face a critical frequency, while the coupled longitudinal waves may face critical frequencies conditionally. The problem of reflection of the thermoelastic waves at the stress-free insulated and isothermal boundary of a homogeneous, isotropic nonlocal thermoelastic half-space has also been investigated. The formulae for various reflection coefficients and their respective energy ratios are determined in various cases. For a particular material, the effects of the angular frequency and the elastic nonlocal parameter have been shown on phase speeds and the attenuation coefficients of the propagating waves. The effect of the elastic nonlocality on the reflection coefficients and the energy ratios has been observed and depicted graphically. Finally, analysis of the various results has been interpreted. 相似文献