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101.
102.
Efficient and continuous monoacylation of symmetrical diamines performed in microreactors yielded superior selectivity to that predicted by statistical considerations. It is highly valuable that the kinetically controlled product in high yields was achieved without any special catalyst at ambient temperature. 相似文献
103.
Hoa V. Phan Pradip Chakraborty Meimei Chen Yitzi M. Calm Dr. Kirill Kovnir Lawrence K. Keniley Jr. Jordan M. Hoyt Elisabeth S. Knowles Dr. Céline Besnard Prof. Mark W. Meisel Prof. Andreas Hauser Prof. Catalina Achim Prof. Michael Shatruk 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(49):15805-15815
Three iron(II) complexes, [Fe(TPMA)(BIM)](ClO4)2?0.5H2O ( 1 ), [Fe(TPMA)(XBIM)](ClO4)2 ( 2 ), and [Fe(TPMA)(XBBIM)](ClO4)2 ?0.75CH3OH ( 3 ), were prepared by reactions of FeII perchlorate and the corresponding ligands (TPMA=tris(2‐pyridylmethyl)amine, BIM=2,2′‐biimidazole, XBIM=1,1′‐(α,α′‐o‐xylyl)‐2,2′‐biimidazole, XBBIM=1,1′‐(α,α′‐o‐xylyl)‐2,2′‐bibenzimidazole). The compounds were investigated by a combination of X‐ray crystallography, magnetic and photomagnetic measurements, and Mössbauer and optical absorption spectroscopy. Complex 1 exhibits a gradual spin crossover (SCO) with T1/2=190 K, whereas 2 exhibits an abrupt SCO with approximately 7 K thermal hysteresis (T1/2=196 K on cooling and 203 K on heating). Complex 3 is in the high‐spin state in the 2–300 K range. The difference in the magnetic behavior was traced to differences between the inter‐ and intramolecular interactions in 1 and 2 . The crystal packing of 2 features a hierarchy of intermolecular interactions that result in increased cooperativity and abruptness of the spin transition. In 3 , steric repulsion between H atoms of one of the pyridyl substituents of TPMA and one of the benzene rings of XBBIM results in a strong distortion of the FeII coordination environment, which stabilizes the high‐spin state of the complex. Both 1 and 2 exhibit a photoinduced low‐spin to high‐spin transition (LIESST effect) at 5 K. The difference in the character of intermolecular interactions of 1 and 2 also manifests in the kinetics of the decay of the photoinduced high‐spin state. For 1 , the decay rate constant follows the single‐exponential law, whereas for 2 it is a stretched exponential, reflecting the hierarchical nature of intermolecular contacts. The structural parameters of the photoinduced high‐spin state at 50 K are similar to those determined for the high‐spin state at 295 K. This study shows that N‐alkylation of BIM has a negligible effect on the ligand field strength. Therefore, the combination of TPMA and BIM offers a promising ligand platform for the design of functionalized SCO complexes. 相似文献
104.
This paper contains selected applications of the new tangential extremal principles and related results developed in Mordukhovich and Phan (Math Program 2011) to calculus rules for infinite intersections of sets and optimality conditions for problems of semi-infinite programming and multiobjective optimization with countable constraints. 相似文献
105.
The paper describes a parallel algorithm for computing an n-dimensional Delaunay tessellation using a divide-conquer strategy. Its implementation (using MPI library for C) in the case
n = 2, relied on restricted areas to discard non-Delaunay edges, is executed easily on PC clusters. We shows that the convexity
is a crucial factor of efficiency of the parallel implementation over the corresponding sequential one. 相似文献
106.
We prove that the maximum number N c of non-relativistic electrons that a nucleus of charge Z can bind is less than 1.22Z + 3Z 1/3. This improves Lieb’s upper bound N c < 2Z + 1 Lieb (Phys Rev A 29:3018–3028, 1984) when Z ≥ 6. Our method also applies to non-relativistic atoms in magnetic field and to pseudo-relativistic atoms. We show that in these cases, under appropriate conditions, \({\limsup_{Z \to \infty}N_c/Z \le 1.22}\). 相似文献
107.
Vu H.H. Nguyen Son H. Doan Tram T. Van Phuc H. Pham Tran T.N. Nguyen Ngoc N. Nguyen Thach N. Tu Nam T.S. Phan 《应用有机金属化学》2019,33(4)
Iron‐based metal–organic framework VNU‐20 was utilized as a heterogeneous catalyst for cascade reactions between ketoximes and dibenzyl ether to produce 2,4,6‐triphenylpyridines. Additionally, benzyl alcohol and (dimethoxymethyl)benzene could be used as an alternative starting materials for the transformation. The oxidant exhibited a remarkable impact on the reactions, and di‐tert‐butylperoxide was the most appropriate candidate. The VNU‐20 displayed higher efficiency than many homogeneous and heterogeneous catalysts. The catalyst was reusable for the cascade reactions without a noticeable deterioration in catalytic activity. This transformation is new, and would offer alternative routes to triphenylpyridines utilizing ketoximes as building blocks. 相似文献
108.
Nguyen Lam M. van Dijk Marten Phan Dzung T. Nguyen Phuong Ha Weng Tsui-Wei Kalagnanam Jayant R. 《Computational Optimization and Applications》2022,82(3):561-593
Computational Optimization and Applications - We introduce NC-SARAH for non-convex optimization as a practical modified version of the original SARAH algorithm that was developed for convex... 相似文献
109.
110.
Nabil A. Younes Md. Mezanur Rahman Ahmed A. Wardany Mona F. A. Dawood Mohammad Golam Mostofa Sanjida Sultana Keya Arafat Abdel Hamed Abdel Latef Lam-Son Phan Tran 《Molecules (Basel, Switzerland)》2021,26(9)
The increasing culinary use of onion (Alium cepa) raises pressure on the current production rate, demanding sustainable approaches for increasing its productivity worldwide. Here, we aimed to investigate the beneficial effects of licorice (Glycyrrhiza glabra) root extract (LRE) in improving growth, yield, nutritional status, and antioxidant properties of two high-yielding onion cultivars, Shandaweel and Giza 20, growing under field conditions in two consecutive years. Our results revealed that pretreatments of both onion cultivars with LRE exhibited improved growth indices (plant height and number of leaves) and yield-related features (bulb length, bulb diameter, and bulb weight) in comparison with the corresponding LRE-devoid control plants. Pretreatments with LRE also improved the nutritional and antioxidant properties of bulbs of both cultivars, which was linked to improved mineral (e.g., K+ and Ca2+) acquisition, and heightened activities of enzymatic antioxidants (e.g., superoxide dismutase, catalase, ascorbate peroxidase, glutathione peroxidase, and glutathione S-transferase) and increased levels of non-enzymatic antioxidants (e.g., ascorbic acid, reduced glutathione, phenolics, and flavonoids). LRE also elevated the contents of proline, total free amino acids, total soluble carbohydrates, and water-soluble proteins in both onion bulbs. In general, both cultivars displayed positive responses to LRE pretreatments; however, the Shandaweel cultivar performed better than the Giza 20 cultivar in terms of yield and, to some extent, bulb quality. Collectively, our findings suggest that the application of LRE as biostimulant might be an effective strategy to enhance bulb quality and ultimately the productivity of onion cultivars under field conditions. 相似文献