Experimental and DFT Investigations Reveal the Influence of the Outer Coordination Sphere on the Vibrational Spectra of Nickel-Substituted Rubredoxin, a Model Hydrogenase Enzyme.
Experimental and DFT Investigations Reveal the Influence of the Outer Coordination Sphere on the Vibrational Spectra of Nickel-Substituted Rubredoxin, a Model Hydrogenase Enzyme.
复制标题
实验和 DFT 研究揭示了外配位球对镍取代红氧还蛋白（一种模型氢化酶）振动光谱的影响。
DOI：
10.1021/acs.inorgchem.6b02934
复制
发表时间：
2017
影响因子：
4.6
通讯作者：
Shafaat,HannahS
中科院分区：
文献类型：
--
作者：
Slater,JeffreyW;Marguet,SeanC;Cirino,SabrinaL;Maugeri,PearsonT;Shafaat,HannahS
镍取代鲁布还蛋白(NIRD)是一种模拟氢酶的功能性酶，对电催化和溶液制氢具有很高的活性。如果使用了适当的技术，光谱方法可以为催化机理提供有价值的见解。在本研究中，我们利用多波长共振拉曼光谱结合密度泛函理论，在一个扩展的NIRD活性中心模型上研究了该体系休止态的电子结构和几何结构。在实验和理论之间观察到了很好的一致性，允许在频率和强度分析的基础上进行简正模式分配。在共振拉曼光谱中，金属配位体和配位体中心的振动模式都得到了增强。后者提供了关于氢键网络和由于二次配位球中的扰动而引起的结构扭曲的信息。为了再现高频振动模式的共振增强模式，必须在计算模型中包括次级配位球。还从实验和计算两方面研究了NiIIIRd态的结构和还原势能。这项工作开始为计算共振拉曼光谱奠定基础，为研究NIRD的催化中间体提供预测的方式。
Nickel-substituted rubredoxin (NiRd) is a functional enzyme mimic of hydrogenase, highly active for electrocatalytic and solution-phase hydrogen generation. Spectroscopic methods can provide valuable insight into the catalytic mechanism, provided the appropriate technique is used. In this study, we have employed multiwavelength resonance Raman spectroscopy coupled with DFT calculations on an extended active-site model of NiRd to probe the electronic and geometric structures of the resting state of this system. Excellent agreement between experiment and theory is observed, allowing normal mode assignments to be made on the basis of frequency and intensity analyses. Both metal–ligand and ligand-centered vibrational modes are enhanced in the resonance Raman spectra. The latter provide information about the hydrogen bonding network and structural distortions due to perturbations in the secondary coordination sphere. To reproduce the resonance enhancement patterns seen for high-frequency vibrational modes, the secondary coordination sphere must be included in the computational model. The structure and reduction potential of the NiIIIRd state have also been investigated both experimentally and computationally. This work begins to establish a foundation for computational resonance Raman spectroscopy to serve in a predictive fashion for investigating catalytic intermediates of NiRd.