Efficient Catalytic Interconversion between NADH and NAD+ Accompanied by Generation and Consumption of Hydrogen with a Water-Soluble Iridium Complex at Ambient Pressure and Temperature

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• 作者：Yuta Maenaka ; Tomoyoshi Suenobu ; Shunichi Fukuzumi
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：January 11, 2012
• 年：2012
• 卷：134
• 期：1
• 页码：367-374
• 全文大小：455K
• 年卷期：v.134,no.1(January 11, 2012)
• ISSN：1520-5126

文摘

Regioselective hydrogenation of the oxidized form of 尾-nicotinamide adenine dinucleotide (NAD⁺) to the reduced form (NADH) with hydrogen (H₂) has successfully been achieved in the presence of a catalytic amount of a [C,N] cyclometalated organoiridium complex [Ir^III(Cp*)(4-(1H-pyrazol-1-yl-魏N²)benzoic acid-魏C³)(H₂O)]₂ SO₄ [1]₂路SO₄ under an atmospheric pressure of H₂ at room temperature in weakly basic water. The structure of the corresponding benzoate complex Ir^III(Cp*)(4-(1H-pyrazol-1-yl-魏N²)-benzoate-魏C³)(H₂O) 2 has been revealed by X-ray single-crystal structure analysis. The corresponding iridium hydride complex formed under an atmospheric pressure of H₂ undergoes the 1,4-selective hydrogenation of NAD⁺ to form 1,4-NADH. On the other hand, in weakly acidic water the complex 1 was found to catalyze the hydrogen evolution from NADH to produce NAD⁺ without photoirradiation at room temperature. NAD⁺ exhibited an inhibitory behavior in both catalytic hydrogenation of NAD⁺ with H₂ and H₂ evolution from NADH due to the binding of NAD⁺ to the catalyst. The overall catalytic mechanism of interconversion between NADH and NAD⁺ accompanied by generation and consumption of H₂ was revealed on the basis of the kinetic analysis and detection of the catalytic intermediates.