1999-00-4Relevant articles and documents
Relative Study of Luminescent Properties with Judd-Ofelt Characterization in Trivalent Europium Complexes Comprising ethyl-(4-fluorobenzoyl) Acetate
Devi, Rekha,Chahar, Sangeeta,Khatkar,Taxak,Boora, Priti
, p. 1349 - 1358 (2017)
Five new europium(III) complexes Eu(p-EFBA)3.(H2O)2 (C1), Eu(p-EFBA)3.neo (C2), Eu(p-EFBA)3.batho (C3), Eu(p-EFBA)3.phen (C4), Eu(p-EFBA)3.bipy (C5) have been synthesized by using ethyl-(4-fluorobenzoyl) acetate (p-EFBA) as β-ketoester ligand and neocuproine (neo), bathophenanthroline (batho), 1,10-phenanthroline (phen) and 2,2-bipyridyl (bipy) as ancillary ligands. The synthesized complexes C1-C5 were characterized by elemental analysis, nuclear magnetic resonance spectroscopy (1H-NMR), infrared (IR) spectroscopy, thermogravimetric analysis (TG/DTG), UV-visible and photoluminescence (PL) spectroscopy. The relative study of luminescence spectra of complexes with the previously reported complexes of isomeric ligand (ortho and meta substituted ligand) indicate the higher luminescence properties of complexes as an effect of fluorine position on β-ketoester ligand. The para substituted ligand shows a remarkable effect on quantum efficiencies and Judd-Ofelt intensity parameters (Ω2, Ω4) of the complexes. The higher value of intensity parameter Ω2 associated with hypersensitive 5D0?→?7F2 transition of europium(III) ion revealing highly polarizable ligand field. The purposed energy transfer mechanism of complexes indicates the efficient energy transfer in complexes.
Electrochemical Oxidative Cyclization: Synthesis of Polysubstituted Pyrrole from Enamines
Chen, Zhiwei,Shi, Guang,Tang, Wei,Sun, Jie,Wang, Wenxing
supporting information, p. 951 - 955 (2021/02/03)
A conceptually novel method for the preparation of pyrrole is described by electrochemical-oxidation-induced intermolecular annulation via enamines. In a simple undivided cell, based on a sodium acetate-facilitated, polysubstituted pyrrole derivations has been facilely synthesized under external oxidant-free condition. This electrosynthetic approach providing an environmentally benign protocol for C?C bond cross-coupling and oxidative annulation, which features unparalleled broad scope of substrates and practicality.
Sulfur-controlled and rhodium-catalyzed formal (3 + 3) transannulation of thioacyl carbenes with alk-2-enals and mechanistic insights
Wu, Qiuyue,Dong, Ziyang,Xu, Jiaxi,Yang, Zhanhui
supporting information, p. 3173 - 3180 (2021/04/21)
A rhodium-catalyzed denitrogenative formal (3 + 3) transannulation of 1,2,3-thiadiazoles with alk-2-enals is achieved, producing 2,3-dihydrothiopyran-4-ones in moderate to excellent yields. An inverse KIE of 0.49 is obtained, suggesting the reversibility of the oxidative addition of thioacyl Rh(i) carbenes to alk-2-enals. The late-stage structural modifications of steroid compounds are realized. Moreover, our studies show that thioacyl carbenes have different reactivities to those of α-oxo and α-imino carbenes, and highlight the importance of heteroatoms in deciding the reactivities of heterovinyl carbenes.
Iridium-Catalyzed Enantioselective and Diastereoselective Hydrogenation of Racemic β’-Keto-β-Amino Esters via Dynamic Kinetic Resolution
He, Jiayin,Huang, An,Ling, Fei,Wang, Shiliang,Wang, Yifan,Wang, Ze,Zhao, Xianghua,Zhong, Weihui
supporting information, p. 4714 - 4719 (2021/09/02)
An iridium/f-diaphos catalytic system for the enantioselective hydrogenation of α-substituted β-ketoesters via dynamic kinetic resolution is reported. The desired anti β’-hydroxy-β-amino esters were obtained in moderate to good yields (60–95%) with 72–99% ees and 91:9 to 99:1 drs. This protocol tolerates various functional groups and could be easily conducted on gram scale with lower catalyst loading (TON up to 9100). (Figure presented.).
