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91.
M. Chem. Laura Nunes dos Santos Comprido Dr. Johannes E. M. N. Klein Prof. Dr. Gerald Knizia Prof. Dr. Johannes Kästner Prof. Dr. A. Stephen K. Hashmi 《Angewandte Chemie (International ed. in English)》2015,54(35):10336-10340
Bonding and stabilizing effects in gold carbene complexes are investigated by using Kohn–Sham density functional theory (DFT) and the intrinsic bond orbital (IBO) approach. The π‐stabilizing effects of organic substituents at the carbene carbon atom coordinated to the gold atom are evaluated for a series of recently isolated and characterized complexes, as well as intermediates of prototypical 1,6‐enyne cyclization reactions. The results indicate that these effects are of particular importance for gold complexes especially because of the low π‐backbonding contribution from the gold atom. 相似文献
92.
CO Extrusion in Homogeneous Gold Catalysis: Reactivity of Gold Acyl Species Generated through Water Addition to Gold Vinylidenes 下载免费PDF全文
M. Sc. Janina Bucher B. Sc. Tim Stößer Dr. Matthias Rudolph Dr. Frank Rominger Prof. Dr. A. Stephen K. Hashmi 《Angewandte Chemie (International ed. in English)》2015,54(5):1666-1670
Herein, we describe a new gold‐catalyzed decarbonylative indene synthesis. Synergistic σ,π‐activation of diyne substrates leads to gold vinylidene intermediates, which upon addition of water are transformed into gold acyl species, a type of organogold compound hitherto only scarcely reported. The latter are shown to undergo extrusion of CO, an elementary step completely unknown for homogeneous gold catalysis. By tuning the electronic and steric properties of the starting diyne systems, this new reactivity could be exploited for the synthesis of indene derivatives in high yields. 相似文献
93.
94.
Kumar Yogesh Rawal Sangeeta Joshi Bhawana Hashmi S. A. 《Journal of Solid State Electrochemistry》2019,23(3):667-692
Journal of Solid State Electrochemistry - Supercapacitors means electrochemical capacitors are being considered these days to be a good alternative for the conventional power sources (fuel cells... 相似文献
95.
Based on the gold‐catalyzed synthesis of methyleneoxazolines, a one‐pot combination with an Alder‐ene reaction was developed. For azodicarboxylates, good to very good yields (51–99 %) of the oxazolemethylhydrazinedicarboxylates were achieved with 3 mol % of the Gagosz catalyst, [Ph3PAuNTf3]. In a less‐selective reaction, 4‐phenyl‐3H‐1,2,4‐triazol‐3,5(4 H)‐dione gave lower yields (41–49 %) of the corresponding oxazolemethylphenyltriazolidinediones. Overall, five new bonds were formed. Tetracyanoethylene afforded a cyclobutane derivative through a [2+2] cycloaddition reaction at ?40 °C, but only 45 % of the spiro compound was obtained. The less‐readily available KITPHOS ligands on gold gave even higher yields at lower catalyst loadings (2 mol %), but longer reaction times were required. 相似文献
96.
The gelation ability of diterpenes was investigated by applying aromatic linker steroid strategy. Four new mono (1) and bis-urea (2–4) derivatives of dehydroabietylamine (DAA) (a tricyclic diterpene amine) were synthesized on reaction of respective isocyanates with DAA and characterized through spectroscopic data. Three of these (1, 2, and 4) were obtained as low-molecular-weight organogelators that can form thermally reversible organogels.
Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for full experimental and spectral details. 相似文献
97.
Hashmi AS Rivas Nass A Bats JW Bolte M 《Angewandte Chemie (International ed. in English)》1999,38(22):3370-3373
Unexpected stability is observed for the palladacycloheptane rac-2, which is obtained as major product and single diastereomer from the cyclization of 1 and Pd(0). Up to a temperature of 50 degrees C 2 shows neither reductive elimination nor intramolecular insertion of another olefin. 相似文献
98.
Simple Zeros of the Riemann Zeta-Function 总被引:1,自引:0,他引:1
Assuming the Riemann Hypothesis, Montgomery showed by meansof his pair correlation method that at least two-thirds of thezeros of Riemann's zeta-function are simple. Later he and Taylorimproved this to 67.25 percent and, more recently, Cheer andGoldston increased the percentage to 67.2753. Here we proveby a new method that if the Riemann and Generalized LindelöofHypotheses hold, then at least 70.3704 percent of the zerosare simple and at least 84.5679 percent are distinct. Our methoduses mean value estimates for various functions defined by Dirichletseries sampled at the zeros of the Riemann zeta-function. 1991Mathematics Subject Classification: 11M26. 相似文献
99.
M. H. Hashmi A. A. Ayaz Maqbool Ahmad Shahid 《Fresenius' Journal of Analytical Chemistry》1965,211(6):417-419
Summary A simple, accurate and rapid method is described for the determination of hydrazine by direct titration with hypobromite using Bordeaux B as indicator. The procedure can also be employed for the determination of hypobromite and bromate by titration with standard hydrazine.
Zusammenfassung Zur Bestimmung von Hydrazin wird die direkte Titration mit Hypobromitlösung und Bordeaux B als Indicator empfohlen. Das Verfahren ist einfach, rasch durchführbar und liefert genaue Ergebnisse. Es kann auch zur Bestimmung von Hypobromit und Bromat durch Titration mit Hydrazinlösung verwendet werden.相似文献
100.