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11.
Linear {NiII–LnIII–NiII} Complexes Containing Twisted Planar Ni(μ‐phenolate)2Ln Fragments: Synthesis,Structure, and Magnetothermal Properties 下载免费PDF全文
Sourav Das Atanu Dey Subrata Kundu Sourav Biswas Prof. Dr. A. J. Mota Prof. Dr. Enrique Colacio Prof. Dr. Vadapalli Chandrasekhar 《化学:亚洲杂志》2014,9(7):1876-1887
Sequential reaction of a multisite LH4 ligand {2‐[2‐hydroxy‐3‐(hydroxymethyl)‐5‐methylbenzylideneamino]‐2‐methylpropane‐1,3‐diol} with appropriate lanthanide salts followed by the addition of Ni(NO3)2 ? 6 H2O in a 4:1:2 stoichiometric ratio in the presence of triethylamine afforded four heterobimetallic trinuclear complexes [Ni2Gd(LH3)4] ? 3 NO3 ? 3 MeOH ? H2O ? CH3CN ( 1 ), [Ni2Tb(LH3)4] ? 3 NO3 ? 3 MeOH ? CH3CN ( 2 ), [Ni2Dy(LH3)4] ? 3 NO3 ? 3 MeOH ? H2O ? CH3CN ( 3 ), and [Ni2Ho(LH3)4] ? 3 NO3 ? 3 MeOH ? H2O ? CH3CN ( 4 ). Complexes 1 – 4 possess linear trimetallic cores with a central lanthanide ion. Magnetic studies revealed a predominant ferromagnetic interaction between the Ni and Ln centers. Alternating current susceptibility measurements of complex 3 showed a small frequency dependence of the out‐of‐phase signal, χ′′M , under zero direct current field, but without achieving a net maximum above 2 K. Magnetic studies on 1 revealed that it has a significant magnetocaloric effect. 相似文献
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AbstractEffective extraction of phyto-biomolecules insures retaining maximum functionality along with higher recovery. In this study, ultrasound-solvent assisted extraction (USAE) was employed for optimal extraction of phyto-biomolecules from Sesamum indicum (sesame) leaves using the approach of Response Surface Methodology (RSM). The optimized condition of 200?W power, 59% methanol concentration with 1:14?g/mL solid–liquid ratio and 15?min of extraction time yielded 367.39?±?1.85?mg GAE/100?g of total phenolic content, 96.72?±?3.27% of free radical scavenging activity and 81.20?±?2.87% of iron chelating activity respectively. The extract consist of essential phytocomponents like gallic acid, chlorogenic acid, and quercetin with lipid peroxidation activities of >50% over incubation time of 48?h. Also, showed antimicrobial activity against various Gram’s negative and positive food borne pathogens. The results of this study implied the importance of USAE for effective and optimum recovery of phyto-biomolecules from Sesame leaves with retained functional properties. 相似文献
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Ranjit Bag Sourav Kar Suvam Saha Suman Gomosta Beesam Raghavendra Thierry Roisnel Sundargopal Ghosh 《化学:亚洲杂志》2020,15(6):780-786
Triply‐bridging bis‐{hydrido(borylene)} and bis‐borylene species of groups 6, 8 and 9 transition metals are reported. Mild thermolysis of [Fe2(CO)9] with an in situ produced intermediate, generated from the low‐temperature reaction of [Cp*WCl4] (Cp*=η5‐C5Me5) and [LiBH4?THF] afforded triply‐bridging bis‐{hydrido(borylene)}, [(μ3‐BH)2H2{Cp*W(CO)2}2{Fe(CO)2}] ( 1 ) and bis‐borylene, [(μ3‐BH)2{Cp*W(CO)2}2{Fe(CO)3}] ( 2 ). The chemical bonding analyses of 1 show that the B?H interactions in bis‐{hydrido (borylene)} species is stronger as compared to the M?H ones. Frontier molecular orbital analysis shows a significantly larger energy gap between the HOMO‐LUMO for 2 as compared to 1 . In an attempt to synthesize the ruthenium analogue of 1 , a similar reaction has been performed with [Ru3(CO)12]. Although we failed to get the bis‐{hydrido(borylene)} species, the reaction afforded triply‐bridging bis‐borylene species [(μ3‐BH)2{WCp*(CO)2}2{Ru(CO)3}] ( 2′ ), an analogue of 2 . In search for the isolation of bridging bis‐borylene species of Rh, we have treated [Co2(CO)8] with nido‐[(RhCp*)2(B3H7)], which afforded triply‐bridging bis‐borylene species [(μ3‐BH)2(RhCp*)2Co2(CO)4(μ‐CO)] ( 3 ). All the compounds have been characterized by means of single‐crystal X‐ray diffraction study; 1H, 11B, 13C NMR spectroscopy; IR spectroscopy and mass spectrometry. 相似文献
14.
Sourav Dey Gopalan Rajaraman Hélène Bolvin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(68):e202201883
[{Mn(TPA)I}{UO2(Mesaldien)}{Mn(TPA)I}]I formula (here TPA=tris(2-pyridylmethyl)amine and Mesaldien=N,N’-(2-aminomethyl)diethylenebis(salicylidene imine)) reported by Mazzanti and coworkers (Chatelain et al. Angew. Chem. Int. Ed. 2014 , 53, 13434) is so far the best Single Molecule Magnet (SMM) in the {3d–5f} class of molecules exhibiting barrier height of magnetization reversal as high as 81.0 K. In this work, we have employed a combination of ab initio CAS and DFT methods to fully characterize this compound and to extract the relevant spin Hamiltonian parameters. We show that the signs of the magnetic coupling and of the g-factors of the monomers are interconnected. The central magnetic unit [UVO2]+ is described by a Kramers Doublet (KD) with negative g-factors, due to a large orbital contribution. The magnetic coupling for the {Mn(II)-U(V)} pair is modeled by an anisotropic exchange Hamiltonian: all components are ferromagnetic in terms of spin moments, the parallel component JZ twice larger as the perpendicular one J⊥. The spin density distribution suggests that spin polarization on the U(V) center favors the ferromagnetic coupling. Further, the JZ/J⊥ ratio, which is related to the barrier height, was found to correlate to the corresponding spin contribution of the g-factors of the U(V) center. This correlation established for the first time offers a direct way to estimate this important ratio from the corresponding gS-values, which can be obtained using traditional ab initio packages and hence has a wider application to other {3d–5f} magnets. It is finally shown that the magnetization barrier height is tuned by the splitting of the [UVO2]+ 5 f orbitals. 相似文献
15.
A p‐Hydroxyphenacyl–Benzothiazole–Chlorambucil Conjugate as a Real‐Time‐Monitoring Drug‐Delivery System Assisted by Excited‐State Intramolecular Proton Transfer 下载免费PDF全文
Shrabani Barman Sourav K. Mukhopadhyay Sandipan Biswas Surajit Nandi Moumita Gangopadhyay Satyahari Dey Anakuthil Anoop N. D. Pradeep Singh 《Angewandte Chemie (International ed. in English)》2016,55(13):4194-4198
Among the well‐known phototriggers, the p‐hydroxyphenacyl (pHP) group has consistently enabled the very fast, efficient, and high‐conversion release of active molecules. Despite this unique behavior, the pHP group has been ignored as a delivery agent, particularly in the area of theranostics, because of two major limitations: Its excitation wavelength is below 400 nm, and it is nonfluorescent. We have overcome these limitations by incorporating a 2‐(2′‐hydroxyphenyl)benzothiazole (HBT) appendage capable of rapid excited‐state intramolecular proton transfer (ESIPT). The ESIPT effect also provided two unique advantages: It assisted the deprotonation of the pHP group for faster release, and it was accompanied by a distinct fluorescence color change upon photorelease. In vitro studies showed that the p‐hydroxyphenacyl–benzothiazole–chlorambucil conjugate presents excellent properties, such as real‐time monitoring, photoregulated drug delivery, and biocompatibility. 相似文献
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18.
Sabyasachi Ghosh S. Mallik Sourav Sarkar 《The European Physical Journal C - Particles and Fields》2010,70(1-2):251-262
We analyse the structure of one-loop self-energy graphs for the ρ meson in real time formulation of finite temperature field theory. We find the discontinuities of these graphs across the unitary and the Landau cuts. These contributions are identified with different sources of medium modification discussed in the literature. We also calculate numerically the imaginary and the real parts of the self-energies and construct the spectral function of the ρ meson, which are compared with an earlier determination. A significant contribution arises from the unitary cut of the π ω loop, that was ignored so far in the literature. 相似文献
19.
A. Chatterjee A. Sarkar Sourav Bhattacharya P. Mukherjee N. Gayathri P. Barat 《Physics letters. A》2008,372(22):4016-4020
Tensile tests were carried out by deforming polycrystalline samples of substitutional Al–2.5%Mg alloy at room temperature for a range of strain rates. The Portevin–Le Chatelier (PLC) effect was observed throughout the strain rate regime. The deformation bands in this region are found to be of type A in nature. From the analysis of the experimental stress time series data we could infer that the dynamics of type A dislocation band propagation is a Markov process. 相似文献
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