Galiana-Cameo María, Borraz Marina, Zelenkova Yaroslava, Passarelli Vincenzo, Lahoz Fernando J, Pérez-Torrente Jesús J, Oro Luis A, Di Giuseppe Andrea, Castarlenas Ricardo
Departamento de Química Inorgánica-Instituto de, Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC, C/Pedro Cerbuna 12, CP., 50009, Zaragoza, Spain.
Centro Universitario de la Defensa, Ctra Huesca S/N, 50090, Zaragoza, Spain.
Chemistry. 2020 Aug 3;26(43):9598-9608. doi: 10.1002/chem.202001584. Epub 2020 Jul 7.
A series of Rh(κ -BHetA)(η -coe)(IPr) complexes bearing 1,3-bis-hetereoatomic acidato ligands (BHetA) including carboxylato (O,O), thioacetato (O,S), amidato (O,N), thioamidato (N,S), and amidinato (N,N), have been prepared by reaction of the dinuclear precursor [Rh(μ-Cl)(IPr)(η -coe)] with the corresponding anionic BHetA species. The Rh -NHC-BHetA compounds catalyze the dimerization of aryl alkynes, showing excellent selectivity for the head-to-tail enynes. Among them, the acetanilidato-based catalyst has shown an outstanding catalytic performance reaching unprecedented TOF levels of 2500 h with complete selectivity for the gem-isomer. Investigation of the reaction mechanism supports a non-oxidative pathway in which the BHetA ligand behaves as proton shuttle through intermediate κ -HBHetA species. However, in the presence of pyridine as additive, the identification of the common Rh H(C≡CPh) (IPr)(py) intermediate gives support for an alternative oxidative route.
通过双核前体[Rh(μ-Cl)(IPr)(η -coe)]与相应的阴离子型1,3-双杂原子酸根配体（BHetA）反应，制备了一系列带有1,3-双杂原子酸根配体（包括羧基（O,O）、硫代乙酸根（O,S）、酰胺基（O,N）、硫代酰胺基（N,S）和脒基（N,N））的Rh(κ -BHetA)(η -coe)(IPr)配合物。Rh-NHC-BHetA化合物催化芳基炔烃的二聚反应，对头对头烯炔表现出优异的选择性。其中，基于乙酰苯胺基的催化剂表现出卓越的催化性能，达到了前所未有的2500 h的TOF水平，对偕二异构体具有完全选择性。反应机理研究支持了一种非氧化途径，其中BHetA配体通过中间体κ -HBHetA物种充当质子穿梭体。然而，在吡啶作为添加剂存在的情况下，常见的Rh H(C≡CPh) (IPr)(py)中间体的鉴定支持了另一种氧化途径。
