1151920-00-1Relevant articles and documents
Symmetrical and Non-symmetrical Pd (II) Pincer Complexes Bearing Mesoionic N-heterocyclic Thiones: Synthesis, Characterizations and Catalytic Properties
Yan, Xuechao,Zhang, Bo,Zhang, Xin,Wang, Haiying,Duan, Yu-Ai,Guo, Shuai
, (2020/07/14)
In contrast to well-established symmetrical pincer complexes, non-symmetrical metal pincers with the loss of C2v symmetry are much less studied. In this work, mesoionic NHTs (NHTs = N-heterocyclic thiones), which can be viewed as the sulfur adducts of mesoionic carbenes, are incorporated into pincer complexes for the first time. Two symmetrical and non-symmetrical phenylene-bridged bis (NHT) compounds 3a/3b were synthesized as proligands via a “cycloaddition-alkylation-thionation” reaction sequence. In a case to access bis (NHT) compound 3c, N-dealkylation reactions occurred. The carbene NMR signals of NHTs are only partially correlated to the π-accepting abilities of carbenes, which is different from Bertrand's carbene-phosphinidene system. The structural analysis of 3a/3b indicates that they possess C-S partial double bonds. 3a and 3b served as the precursors to access two aryl anion-linked [SCS/S′] pincer complexes 6a/6b. An external base proved to be essential for this cyclopalladation process. The catalytic properties of 6a/6b in the cycloisomerizations of alkynoic acids have been examined. Finally, non-symmetrical complex 6a shows superior catalytic performance in such transformations contrasting to its symmetrical counterpart 6b.
Synthesis of 1,2,3-triazoles in the presence of mixed Mg/Fe oxides and their evaluation as corrosion inhibitors of API 5L X70 steel submerged in HCl
Espinoza-Vázquez,Rodríguez-Gómez,Vergara-Arenas,Lomas-Romero,Angeles-Beltrán,Negrón-Silva,Morales-Serna
, p. 24736 - 24746 (2017/07/11)
In this work, the catalytic capacity of a Mg/Fe layered double hydroxide (LDH) and its mixed oxides to perform Huisgen cycloaddition was studied. The catalytic process was performed in the presence of sodium ascorbate, which was determinant for the success of the 1,3-cycloaddition. The obtained triazoles were evaluated as corrosion inhibitors using electrochemical impedance spectroscopy under static conditions, showing an inhibition efficiency higher than 95% at 50 ppm for some of the triazoles studied. According to the Langmuir isotherm, all the compounds synthesized and analysed exhibit a chemisorption process. Finally, the corrosion process when submerging a steel bar in 1 M HCl was studied using SEM-EDS. This experiment showed that the corrosion process decreases considerably in the presence of 50 ppm of the organic inhibitor.
Copper(II) Acetylacetonate: An Efficient Catalyst for Huisgen-Click Reaction for Synthesis of 1,2,3-Triazoles in Water
Jiang, Yuqin,Li, Xingfeng,Li, Xiyong,Sun, Yamin,Zhao, Yaru,Jia, Shuhong,Guo, Niu,Xu, Guiqing,Zhang, Weiwei
supporting information, p. 1239 - 1245 (2017/09/02)
An efficient and green copper(II) acetylacetonate-catalyzed protocol for the Huisgen-click reaction in water at 100 °C has been established. The protocol was not only suitable for the reaction between organic azides and alkynes, but also suitable for one-pot three-component reaction among alkyl halides, NaN3 and alkynes.
