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Cover Picture: Ligand Noninnocence in Coinage Metal Corroles: A Silver Knife‐Edge (Chem. Eur. J. 47/2015) 下载免费PDF全文
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The reaction of copper beta-octabromo- meso-triarylcorrole derivatives with methyl 2,2-difluoro-2-(fluorosulfonyl)acetate has provided four beta-octakis(trifluoromethyl)corrole complexes, Cu[(CF 3) 8T( p-XP)C] (X = F, H, Me, OMe), in moderate yields. The new complexes present a conglomeration of remarkable substituent effects, both steric and electronic. DFT (OLYP/TZP) geometry optimization of Cu[(CF 3) 8TPC] (i.e., X = H) indicates a sterically hindered, strongly saddled geometry, with numerous short F...F nonbonded contacts of 2.5-2.9 A and certain beta carbons displaced by over 1.5 A relative to the mean corrole plane. The CF 3 groups generally appear as quartets in the (19)F NMR spectra, with unexpectedly large (5) J FF coupling constants of about 14 Hz, apparently a manifestation of the highly crowded structure. The eight CF 3 groups together exert a powerful influence on the redox potentials of the copper corrole core. Thus, the E 1/2ox of Cu[(CF 3) 8TPC] (1.4 V vs saturated calomel electrode) is a full half of a volt above that of Cu(TPC) (0.9 V) and a quarter of a volt above that of Cu(Br 8TPC) (1.14 V). Intriguingly, the beta CF 3 groups also greatly intensify the influence of the meso aryl substituents on the redox potentials, relative to the other Cu[Y 8T( p-XP)C] series, where Y = H, F, and Br. The Cu[(CF 3) 8T( p-XP)C] complexes also exhibit the most red-shifted optical spectra of any series of metallocorroles synthesized to date. Thus, between Cu(TPC) and Cu[(CF 3) 8T( p-MeO-P)C], the Soret maximum shifts by nearly 100 nm. The observed red-shifts are attributed in part to charge-transfer transitions of the Soret region and in part to the extreme nonplanar distortions. 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
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Fuxiang Ji Johan Klarbring Feng Wang Weihua Ning Linqin Wang Chunyang Yin Jos Silvestre Mendoza Figueroa Christian Kolle Christensen Martin Etter Thomas Ederth Licheng Sun Sergei I. Simak Igor A. Abrikosov Feng Gao 《Angewandte Chemie (International ed. in English)》2020,59(35):15191-15194
Environmentally friendly halide double perovskites with improved stability are regarded as a promising alternative to lead halide perovskites. The benchmark double perovskite, Cs2AgBiBr6, shows attractive optical and electronic features, making it promising for high‐efficiency optoelectronic devices. However, the large band gap limits its further applications, especially for photovoltaics. Herein, we develop a novel crystal‐engineering strategy to significantly decrease the band gap by approximately 0.26 eV, reaching the smallest reported band gap of 1.72 eV for Cs2AgBiBr6 under ambient conditions. The band‐gap narrowing is confirmed by both absorption and photoluminescence measurements. Our first‐principles calculations indicate that enhanced Ag–Bi disorder has a large impact on the band structure and decreases the band gap, providing a possible explanation of the observed band‐gap narrowing effect. This work provides new insights for achieving lead‐free double perovskites with suitable band gaps for optoelectronic applications. 相似文献
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Corrigendum: Synthesis of 3,4,5‐Trisubstituted Isoxazoles from Morita–Baylis–Hillman Acetates by an NaNO2/I2‐Mediated Domino Reaction 下载免费PDF全文
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Shashikant U. Dighe Sushobhan Mukhopadhyay Shivalinga Kolle Dr. Sanjeev Kanojiya Sanjay Batra 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(37):11076-11080
An efficient NaNO2/I2‐mediated one‐pot transformation of Morita–Baylis–Hillman (MBH) acetates into alkyl 3‐nitro‐5‐(aryl/alkyl)isoxazole‐4‐carboxylates is described. In a cascade event, initial Michael addition of NaNO2 to the MBH acetate furnishes the allylnitro intermediate which undergoes I2‐catalyzed oxidative α‐C H nitration of the nitromethyl subunit followed by [3+2] cycloaddition to afford the title compounds. Structural elaborations of these highly substituted isoxazoles by SNAr reactions and hydrogenolysis allows access to useful products. 相似文献