pH-Dependent Transfer Hydrogenation of Ketones with HCOONa as a Hydrogen Donor Promoted by (η6-C6Me6)Ru Complexes
pH-Dependent Transfer Hydrogenation of Ketones with HCOONa as a Hydrogen Donor Promoted by (η6-C6Me6)Ru Complexes
复制标题
DOI：
10.1021/om011059x
复制
发表时间：
2002-06
期刊：
影响因子：
2.8
通讯作者：
S. Ogo;Tsutomu Abura;Y. Watanabe
中科院分区：
文献类型：
--
作者：
S. Ogo;Tsutomu Abura;Y. Watanabe
本文报道了一类新型的水溶性有机金属催化剂的开发，用于pH依赖的转移氢化。有机金属水配合物[（η6-C6 Me 6）RuII（bpy）（H2O）]2+（1，bpy = 2，2 '-bipyridine）作为催化剂前体，在水和两相介质中，以HCOONa为氢供体，对水溶性和水不溶性酮进行了pH依赖的转移氢化。无论酮对水的溶解度如何，转移氢化的速率在pH 4.0附近显示出最大值（在两相介质的情况下，采用水相的pH值）。在不存在可还原酮的情况下，作为pH的函数，配合物1与HCOONa反应以提供甲酸根配合物[（η6-C6 Me 6）RuII（bpy）（HCOO）]+（2）作为β-氢消除的中间体，和双氢根配合物[（η6-C6 Me 6）RuII（bpy）H]+（3）作为转移氢化的催化剂。1（PF 6）2、2（HCOO）·HCOOH和[（η6-C6 Me 6）RuII（H2O）3] SO 4·3 H2O {4（SO 4）·3 H2O}的结构，作为起始原料.
The paper reports on the development of a new class of water-soluble organometallic catalysts for pH-dependent transfer hydrogenation. An organometallic aqua complex [(η6-C6Me6)RuII(bpy)(H2O)]2+ (1, bpy = 2,2‘-bipyridine) acts as a catalyst precursor for pH-dependent transfer hydrogenation of water-soluble and -insoluble ketones with HCOONa as a hydrogen donor in water and in biphasic media. Irrespective of the solubility of the ketones toward water, the rate of the transfer hydrogenation shows a sharp maximum around pH 4.0 (in the case of biphasic media, the pH value of the aqueous phase is adopted). In the absence of the reducible ketones, as a function of pH, complex 1 reacts with HCOONa to provide a formato complex [(η6-C6Me6)RuII(bpy)(HCOO)]+ (2) as an intermediate of β-hydrogen elimination and a hydrido complex [(η6-C6Me6)RuII(bpy)H]+ (3) as the catalyst for the transfer hydrogenation. The structures of 1(PF6)2, 2(HCOO)·HCOOH, and [(η6-C6Me6)RuII(H2O)3]SO4·3H2O {4(SO4)·3H2O}, the starting material f...