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991.
Asif Ahmad Suvam Saha Mohammad Zafar Dr. Marie Cordier Dr. Sundargopal Ghosh 《欧洲无机化学杂志》2023,26(21):e202300196
The reactivity of κ2-N,S-chelated ruthenium borate complexes, [Ru(PPh3)(κ2-N,S-(NC7H4S2)Ru{κ3-H,S,S′-H2B (NC7H4S2)2}] ( 1 a ) and [Ru(PPh3)(κ2-N,S-(NC5H4S){κ3-H,S,S′-H2B(NC5H4S)2}] ( 1 b ) with monoboranes have been explored. The prolonged room temperature reaction of [Ru(PPh3){κ2-N,S-(NC7H4S2)}{κ3-H,S,S′-H2B(NC7H4S2)2}], 1 a with an excess of [BH3 ⋅ THF] led to the formation of hydrogen-rich complex, arachno-[PPh3(κ2-B3H8)Ru{κ3-H,S,S′-H2B(NC7H4S2)2] ( 2 ). In a similar fashion, the isomeric ruthenatetraborane complexes of [Ru(PPh3)(κ2-N,S-(B3H8){κ3-H,S,S′-H2B(NC5H4S)2}], 4 and 5 were isolated from the room temperature reaction of 1 b with [BH3 ⋅ THF]. In complex 2 , the borate ligand, [H2B(NC5H4S)2] and the PPh3 occupy the endo and exo sites of the butterfly-shaped RuB3 core, respectively. In contrast, the borate unit [H2B(NC5H4S)2] in 4 sits on the exo position of the butterfly core, while the phosphine ligand occupies the endo site. Multinuclear spectroscopic analyses were done to characterize all new complexes and the structures were further confirmed by single-crystal X-ray diffraction analysis. Density functional theory (DFT) calculations were performed to probe into the bonding modes of these complexes. 相似文献
992.
Vladimír Kubíček Marie Soukupová Milan Nobilis Veronika Křížová Barbora Szotáková Lenka Skálová 《Chromatographia》2008,68(9-10):865-867
A validated LC method is proposed for analysis of flubendazole and its metabolites in biological samples of Haemonchus contortus. Two detectors were used—photodiode-array and spectrofluorimetric. The native fluorescence of reduced flubendazole, the key substance investigated during biological experiments, was used for its fluorimetric detection with a very low limit of quantification (0.63 nmol L?1). 相似文献
993.
The introduction of dynamic covalent polymers, in which the monomer units are linked by reversible covalent bonds and can undergo component exchange, opens up new possibilities for the generation of functional materials. Extending this approach to the generation of dynamic biopolymers in aqueous media, which are able to adapt constitution (sequence, length) to external factors (e.g., environment, medium, template), would provide an alternative approach to the de novo design of functional dynamic bio‐macromolecules. As a first step towards this goal, various mono‐ and bifunctionalised (hetero‐ and homotopic) nucleic acid‐derived building blocks of type I – X have been synthesised for the generation of dynamic main‐chain and side‐chain reversible nucleic acid analogues. Hydrazide‐ and/or acetal (protected carbonyl)‐functionalised components were selected, which differ in terms of flexibility, length, net formal charge, and hydrazide/acetal substituents, in order to explore how such factors may affect the properties (structure, solubility, molecular recognition features) of the polymer products that may be generated by polycondensation. 相似文献
994.
Marie‐Pierre Collin Sven N. Hobbie Erik C. Böttger Andrea Vasella 《Helvetica chimica acta》2008,91(10):1838-1848
In search for new antibiotics we replaced the amide moiety of lincomycin 1 by a 1,2,3‐triazole ring. The 1,2,3‐triazoles 10a – 10k were obtained as single regioisomers by ‘click reaction’ of azide 5 with the alkyne 9k , derived from propyl hygric acid, and the alkyl, aryl, or cycloalkyl alkynes ribosomes 9a – 9j . The new analogues proved inactive towards wild‐type and A2058G mutant. 相似文献
995.
Single crystals of Ga(OH)(C(8)H(4)O(4)).0.74C(8)H(6)O(4) (2) and Ga(OH,F)(C(8)H(4)O(4)).0.74C(8)H(6)O(4) (3) were obtained under hydrothermal conditions. The structures of 2 and 3 have the same topological framework as the previously reported aluminum 1,4-benzenedicarboxylate (BDC), Al(OH)(C(8)H(4)O(4)).0.7C(8)H(6)O(4) (1). The frameworks are built by interconnecting M-OH-M chains (M = Al, Ga) with BDC anions to form large diamond-shaped one-dimensional channels filled with additional H(2)BDC guest molecules occupying disordered positions in the channels. Upon removal of H(2)BDC, other guest molecules such as H(2)O and pyridine can be inserted. In this work, we present a study of the intercalation of aromatic guests (BDC and pyridine) into frameworks of 1-3 by liquid and vapor diffusion into the empty channels of 1 and by single-crystal-to-single-crystal solvothermal guest exchange for 2 and 3. In the case of Al(OH)BDC and Ga(OH,F)BDC, two interconvertible, guest-concentration-dependent phases with different orientations of the pyridine guests have been observed, while only one pyridine orientation is found in Ga(OH)BDC. 相似文献
996.
Kolesniková L Varga J Beckers H Simecková M Zelinger Z Stríteská LN Kania P Willner H Urban S 《The Journal of chemical physics》2008,128(22):224302
More than 160 new hyperfine components of rotational transitions of the free fluoroformyloxyl radical FCO(2) have been measured using the Prague millimeter wave high resolution spectrometer. The frequencies of these transitions together with the previously measured data were analyzed in detail and precise values of magnetic hyperfine and fine parameters were obtained. These new parameters significantly improve the values of previously determined hyperfine parameters which were rather unreliable. The new fine and hyperfine parameters obtained in this study are compatible with those of the simultaneously electron paramagnetic resonance study. Besides that, significantly improved ground state rotational and centrifugal distortion constants of the fluoroformyloxyl radical were derived. 相似文献
997.
Sørensen LM Nielsen KF Jacobsen T Koch AG Nielsen PV Frisvad JC 《Journal of chromatography. A》2008,1205(1-2):103-108
A method for determination of mycophenolic acid (MPA) in dry-cured ham, fermented sausage and liver paté is described. MPA was extracted from meat with bicarbonate-acetonitrile, further cleaned-up by mixed mode reversed phase-anion exchange and detected using a LC-MS system with electrospray ionisation-time-of-flight detection. The limit of detection was 4 microg/kg in sausage and 6 microg/kg in ham and paté. The method was successfully used for quantification of MPA in dry-cured ham and liver paté artificially inoculated with Penicillium brevicompactum. Levels ranged from 190 microg/kg in centre to 11 mg/kg in surface of ham and from 150 microg/kg in bottom to 14 mg/kg in surface of paté. 相似文献
998.
André Marie Fopossi Mbemmo Germaine Djuidjé Kenmoé Timoléon Crépin Kofané 《The European Physical Journal B - Condensed Matter and Complex Systems》2016,89(10):211
We study transport properties of an inertial Brownian motor which moves in a deformable Remoissenet-Peyrad periodic potential and is subjected to both a static bias force and time periodic driving biharmonic force. By modifying the shape of the potential, the anomalous transport is identified for a particular set of the system parameters. For a particular potential shape, the mean velocity of a particle is modified by going from negative to positive values according to the external bias force. These features also depend on both the biharmonic parameter and the phase-lag of two signals. A remarkable transition of the negative velocity depending on the shape of the potential is observed. We also focus on the efficiency of the motor and discuss velocity fluctuation. In addition, within selected system parameters, different types of diffusion particle such as subdiffusion, superdiffusion, normal diffusion, ballistic diffusion, hyperdiffusion and dispersionless transport phenomena are generated in the system. 相似文献
999.
Tiago Maritan Ugulino de Araújo Lisieux Marie M. S. Andrade Carlos Magno Lucídio dos Anjos Formiga Cabral Roberto Quirino do Nascimento Cláudio N. Meneses 《Journal of Heuristics》2016,22(4):365-382
Several papers in the scientific literature use metaheuristics to solve continuous global optimization. To perform this task, some metaheuristics originally proposed for solving combinatorial optimization problems, such as Greedy Randomized Adaptive Search Procedure (GRASP), Tabu Search and Simulated Annealing, among others, have been adapted to solve continuous global optimization problems. Proposed by Hirsch et al., the Continuous-GRASP (C-GRASP) is one example of this group of metaheuristics. The C-GRASP is an adaptation of GRASP proposed to solve continuous global optimization problems under box constraints. It is simple to implement, derivative-free and widely applicable method. However, according to Hedar, due to its random construction, C-GRASP may fail to detect promising search directions especially in the vicinity of minima, which may result in a slow convergence. To minimize this problem, in this paper we propose a set of methods to direct the search on C-GRASP, called Directed Continuous-GRASP (DC-GRASP). The proposal is to combine the ability of C-GRASP to diversify the search over the space with some efficient local search strategies to accelerate its convergence. We compare the DC-GRASP with the C-GRASP and other metaheuristics from literature on a set of standard test problems whose global minima are known. Computational results show the effectiveness and efficiency of the proposed methods, as well as their ability to accelerate the convergence of the C-GRASP. 相似文献
1000.
Dr. Georgian Melinte Dr. Veselina Georgieva Dr. Marie‐Anne Springuel‐Huet Dr. Andreï Nossov Prof. Ovidiu Ersen Dr. Flavien Guenneau Prof. Antoine Gedeon Dr. Ana Palčić Dr. Krassimir N. Bozhilov Dr. Cuong Pham‐Huu Prof. Shilun Qiu Dr. Svetlana Mintova Dr. Valentin Valtchev 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):1881-1881