Catalysis of the hydrogenation of benzophenone by polyhydride complexes of tris(triphenylphosphine)ruthernium
作者:Donald E. Linn、Jack Halpern
DOI:10.1016/0022-328x(87)80284-x
日期:1987.8
The following reactions have been identified in THF solution (P=PPh3): (1) [RuH4P3] (3) + Ph2C=O → [RuH2P3(THF)] (4) + Ph2CHOH. (2) 4 + H2 → 3. (3) 4 + 2Ph2C=O → [RuH(O=CPhC6H4)P3] (5) + Ph2CHOH. (4) 5 + 2H2 → 4 + Ph2CHOH. (5) [RuH3P3]− (1) + Ph2C=O → 4 + Ph2CHO−. (6) 3 + Ph2CHO− → 1 + Ph2CHOH. Each of the following combination of steps constitutes one of a set of interconnected catalytic cycles for
在THF溶液(P = PPh 3)中鉴定出以下反应:(1)[RuH 4 P 3 ](3)+ Ph 2 C = O→[RuH 2 P 3(THF)](4)+ Ph 2 CHOH。(2)4 + H 2 → 3。(3)4 + 2Ph 2 C = O→[RuH(O = CPhC 6 H 4)P 3 ](5)+ Ph 2 CHOH。(4)5 + 2H 2 → 4 + Ph 2 CHOH。(5)[RuH 3P 3 ] - (1)+博士2 C = O→ 4 +博士2 CHO - 。(6)3 +博士2 CHO - → 1 +博士2 CHOH。以下每个步骤的组合构成了一组将Ph 2 C = O氢化为Ph 2 CHOH的相互关联的催化循环中的一个:(1)+(2);(3)+(4); (2)+(6)+(5)。
Basicity of Uranyl Oxo Ligands upon Coordination of Alkoxides
作者:Marianne P. Wilkerson、Carol J. Burns、Harry J. Dewey、Jerod M. Martin、David E. Morris、Robert T. Paine、Brian L. Scott
DOI:10.1021/ic000142u
日期:2000.11.13
Uranium(VI) alkoxide complexes are prepared via metathesis reactions of [UO2Cl2(THF)2]2 with potassium alkoxides in nonaqueous media. The dark red compound U[OCH2C(CH3)3]6, 1, results from redistributive exchange of oxo and neopentoxide ligands between more than one uranium species. Single-crystal X-ray diffraction analysis of 1 reveals a monomer in which the uranium is coordinated in a pseudooctahedral
Synthetic Models for the Cysteinate-Ligated Non-Heme Iron Enzyme Superoxide Reductase: Observation and Structural Characterization by XAS of an Fe<sup>III</sup>−OOH Intermediate
作者:Jason Shearer、Robert C. Scarrow、Julie A. Kovacs
DOI:10.1021/ja012722b
日期:2002.10.1
reductases (SORs) belong to a new class of metalloenzymes that degrade superoxide by reducing it to hydrogen peroxide. These enzymes contain a catalytic iron site that cycles between the Fe(II) and Fe(III) states during catalysis. A key step in the reduction of superoxide has been suggested to involve HO(2) binding to Fe(II), followed by innersphere electron transfer to afford an Fe(III)-OO(H) intermediate.
Thermodynamic and Kinetic Activity Descriptors for the Catalytic Hydrogenation of Ketones
作者:Andrei Chirila、Yiqin Hu、John C. Linehan、David A. Dixon、Eric S. Wiedner
DOI:10.1021/jacs.3c13876
日期:2024.3.13
energy losses. In this study, we develop the use of hydricity and H– self-exchange rates as thermodynamic and kinetic descriptors for the hydrogenation of ketones by molecular catalysts. Two complexes with known hydricity, HRh(dmpe)2 and HCo(dmpe)2, were investigated for the catalytichydrogenation of ketones under mild conditions (1.5 atm and 25 °C). The rhodium catalyst proved to be an efficient catalyst
活性描述符是设计催化剂的有力工具,可以以最小的能量损失有效地利用 H 2 。在这项研究中,我们开发了使用氢度和H-自交换率作为分子催化剂氢化酮的热力学和动力学描述符。研究了两种已知水度的配合物 HRh(dmpe) 2和 HCo(dmpe) 2在温和条件(1.5 atm 和 25 °C)下对酮的催化氢化作用。铑催化剂被证明是多种酮的有效催化剂,而钴催化剂只能氢化缺电子酮。结合实验和电子结构理论,建立了 46 个醇盐/酮对在乙腈和四氢呋喃溶剂中的热力学水度值。通过比较催化剂和底物的羟基度,确定仅在具有放能氢转移步骤的催化剂/酮对中观察到催化作用。机理研究表明, H-转移是催化的限速步骤,允许对H-转移的线性自由能关系(LFER)进行实验和计算构建。进一步的分析表明,LFER 可以使用 Marcus 理论来重现,其中 HRh/Rh +和酮/醇盐对的 H –自交换率用于预测实验测量的 2 kcal
Multifunctional Ruthenium Catalysts: A Novel Borohydride-Stabilized Polyhydride Complex Containing the Basic, Chelating Diphosphine 1,4-Bis(dicyclohexylphosphino)butane and Its Application to Hydrogenation and Murai Catalysis
作者:Samantha D. Drouin、Dino Amoroso、Glenn P. A. Yap、Deryn E. Fogg
DOI:10.1021/om010745t
日期:2002.3.1
[RuCl2(dcypb)(CO)](2) 2 (dcypb = 1,4-bis(dicyclohexylphosphino)butane) was prepared in high yield via phosphine exchange between dcypb and RuCl2(CO)(PPh3)(2)(DMF) (1). Reaction of 2 with 8 equiv of (KBHBu3)-Bu-s affords [fac-RuH3(CO)(dcypb)](-) (3), stabilized by interactions with a K+ counterion and an intact (KBHBu3)-Bu-s molecule in the third coordination sphere. Substantial ion pairing accounts for the stability and high hydrocarbon solubility of 3. Complex 3 effects reduction of benzophenone under unprecedentedly mild conditions, at 1 atm of H-2 in refluxing 2-propanol. It is also active for ortho, functionalization of benzophenone under 20 atm of ethylene. Stoichiometric experiments reveal facile formation of orthometalated RuH(CO)[OC(C6H4)(Ph)](dcypb) (5), an intermediate proposed in both types of catalysis. The catalytic activity of isolated 5 supports this hypothesis in the case of hydrogenation but not of Murai catalysis. The X-ray crystal structures of 3 and 5 are reported.