pH-Dependent Transfer Hydrogenation of Ketones with HCOONa as a Hydrogen Donor Promoted by (η6-C6Me6)Ru Complexes
摘要:
The paper reports on the development of a new class of water-soluble organometallic catalysts for pH-dependent transfer hydrogenation. An organometallic aqua complex [(eta(6)-C6Me6)Ru-II(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 [(eta(6)-C6Me6)Ru-II(bpy)(HCOO)](+) (2) as an intermediate of beta-hydrogen elimination and a hydrido complex [(eta(6)-C6Me6)Ru-II(bpy)H](+) (3) as the catalyst for the transfer hydrogenation. The structures of 1(PF6)(2), 2(HCOO).HCOOH, and [(eta(6)-C6Me6)Ru-II(H2O)(3)]SO4.3H(2)O {4(SO4).3H(2)O}, the starting material for the synthesis of 1, were unequivocally determined by X-ray analysis.
pH-Dependent Transfer Hydrogenation of Ketones with HCOONa as a Hydrogen Donor Promoted by (η6-C6Me6)Ru Complexes
摘要:
The paper reports on the development of a new class of water-soluble organometallic catalysts for pH-dependent transfer hydrogenation. An organometallic aqua complex [(eta(6)-C6Me6)Ru-II(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 [(eta(6)-C6Me6)Ru-II(bpy)(HCOO)](+) (2) as an intermediate of beta-hydrogen elimination and a hydrido complex [(eta(6)-C6Me6)Ru-II(bpy)H](+) (3) as the catalyst for the transfer hydrogenation. The structures of 1(PF6)(2), 2(HCOO).HCOOH, and [(eta(6)-C6Me6)Ru-II(H2O)(3)]SO4.3H(2)O {4(SO4).3H(2)O}, the starting material for the synthesis of 1, were unequivocally determined by X-ray analysis.
Aqueous polymerization of styrene in biphasic media (styrene/water) has been achieved by water-soluble robust mononuclear hydride complexes [(η6-C6Me6)RuII(bpy)H]n(X) [1]n(X), where X = SO4 (n = 2) or CF3SO3 (n = 1), bpy = 2,2‘-bipyridine}. The hydride complex [1]2(SO4) was synthesized from the reaction of an aqua complex [(η6-C6Me6)RuII(bpy)(H2O)](SO4) 2(SO4)} with a water-soluble hydrogen donor
在两相介质(苯乙烯/水)苯乙烯的水性聚合已经由水溶性健壮单核氢化物络合物实现[(η 6 -C 6我6)的Ru II(BPY)H] Ñ(X)[ 1 ] Ñ( X),其中X = SO 4(n = 2)或CF 3 SO 3(n = 1),bpy = 2,2'-联吡啶}。氢化物配合物[ 1 ] 2(SO 4)是从一个水性络合物[(η的反应合成6 -C 6我6)的Ru II(BPY)(H2 O)](SO 4) 2(SO 4)}与H 2 O中的水溶性氢供体HCOONa在70-100°C的pH范围为4-12之间。通过X射线分析,1 H和2 H NMR,IR和电喷雾电离质谱(ESI-MS)确定[ 1 ] 2(SO 4)和1(CF 3 SO 3)的结构。X射线分析显示,复杂1(CF 3 SO 3)采用扭曲的八面体与钌原子几何由一个η协调6 -C 6我6个配体,1个双齿bpy配体和1个占据键位置的末端氢配体。络合物[
Hydride Ion Transfer from Ruthenium(II) Complexes in Water: Kinetics and Mechanism
作者:Carol Creutz、Mei H. Chou、Hua Hou、James T. Muckerman
DOI:10.1021/ic101124q
日期:2010.11.1
and H3CO− in water are estimated as +1.48, −0.76, and +1.57 eV/molecule (+34, −17.5, +36 kcal/mol), respectively. Theoretical studies of the reactions with CO2 reveal a “product-like” transition state with short C−H and long M−H distances. (Reactant) Ru−H stretched 0.68 Å; (product) C−H stretched only 0.04 Å. The role of water solvent was explored by including one, two, or three water molecules in
Accelerating Effect of a Proton on the Reduction of CO<sub>2</sub> Dissolved in Water under Acidic Conditions. Isolation, Crystal Structure, and Reducing Ability of a Water-Soluble Ruthenium Hydride Complex
A water-soluble hydride complex [(eta6-C6Me6)RuII(bpy)H]+ 1, bpy = 2,2'-bipyridine} serves as a robust reducing agent for the reduction of CO2 in water in a pH range of about 3-5 at ambient temperature under stoichiometric conditions. The structure of 1 was unequivocally determined by X-ray analysis. The mechanism of acid-catalyzed reduction of CO2 promoted by 1 in water under acidic conditions is disclosed.
pH-Dependent Transfer Hydrogenation of Ketones with HCOONa as a Hydrogen Donor Promoted by (<i>η</i><sup>6</sup>-C<sub>6</sub>Me<sub>6</sub>)Ru Complexes
作者:Seiji Ogo、Tsutomu Abura、Yoshihito Watanabe
DOI:10.1021/om011059x
日期:2002.7.1
The paper reports on the development of a new class of water-soluble organometallic catalysts for pH-dependent transfer hydrogenation. An organometallic aqua complex [(eta(6)-C6Me6)Ru-II(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 [(eta(6)-C6Me6)Ru-II(bpy)(HCOO)](+) (2) as an intermediate of beta-hydrogen elimination and a hydrido complex [(eta(6)-C6Me6)Ru-II(bpy)H](+) (3) as the catalyst for the transfer hydrogenation. The structures of 1(PF6)(2), 2(HCOO).HCOOH, and [(eta(6)-C6Me6)Ru-II(H2O)(3)]SO4.3H(2)O 4(SO4).3H(2)O}, the starting material for the synthesis of 1, were unequivocally determined by X-ray analysis.