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IRMPD Spectroscopic and Theoretical Structural Investigations of Zinc and Cadmium Dications Bound to Histidine Dimers
The Journal of Physical Chemistry A ( IF 2.7 ) Pub Date : 2020-11-26 , DOI: 10.1021/acs.jpca.0c08861 Brandon C. Stevenson 1 , Jonathan Martens 2 , Giel Berden 2 , Jos Oomens 2, 3 , Mathias Schäfer 4 , P. B. Armentrout 1
The Journal of Physical Chemistry A ( IF 2.7 ) Pub Date : 2020-11-26 , DOI: 10.1021/acs.jpca.0c08861 Brandon C. Stevenson 1 , Jonathan Martens 2 , Giel Berden 2 , Jos Oomens 2, 3 , Mathias Schäfer 4 , P. B. Armentrout 1
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Metallated gas-phase structures consisting of a deprotonated and an intact histidine (His) ligand, yielding M(His-H)(His)+, where M = Zn and Cd, were examined with infrared multiple photon dissociation (IRMPD) action spectroscopy utilizing light from a free-electron laser (FEL). In parallel, quantum chemical calculations identified several low-energy isomers for each complex. Experimental action spectra were compared to linear spectra calculated at the B3LYP level of theory using the 6-311+G(d,p) and def2-TZVP basis sets for the zinc and cadmium complexes, respectively. For both Zn and Cd species, the definitive assignment is complicated by conflicting relative energetics, which were calculated at B3LYP, B3LYP-GD3BJ, B3P86, and MP2(full) levels. Spectral comparison for both species indicates that the dominant conformation, [Nα,Nπ,CO–][CO2–](NπH+), has the deprotonated His chelating the metal at the amine nitrogen, π nitrogen of the imidazole ring, and the deprotonated carbonyl oxygen and that the intact His ligand adopts a salt-bridge bidentate binding motif, coordinating the metal with both carboxylate oxygens. There is also evidence for a conformation where the deprotonated His coordination is maintained, but the intact His ligand adopts a more canonical structure, coordinating with the metal atom at the amine nitrogen and π nitrogen, [Nα,Nπ,CO–][Nα,Nπ]gtgg. For both metallated species, B3LYP, B3P86, and B3LYP-GD3BJ levels of theory appear to describe the relative stability of the dominant zwitterionic species more accurately than the MP2(full) level.
中文翻译：
组氨酸二聚体结合的锌和镉阳离子的IRMPD光谱学和理论结构研究
金属化的气相结构，由去质子化的和完整的组氨酸（His）配体组成，产生M（His-H）（His）+，其中M = Zn和Cd，使用来自自由电子激光（FEL）的光通过红外多光子离解（IRMPD）作用光谱进行了检查。同时，量子化学计算为每种配合物确定了几种低能异构体。使用锌和镉配合物的6-311 + G（d，p）和def2-TZVP基集分别将实验作用谱与在B3LYP理论水平计算的线性谱进行比较。对于Zn和Cd物种，确定的分配都因相对能的冲突而变得复杂，这些相对能在B3LYP，B3LYP-GD3BJ，B3P86和MP2（full）水平下计算。两种物种的光谱比较表明，主要构象[ Nα，Nπ，CO – ] [CO 2 –]（N π ħ +），具有去质子化的他的螯合剂在胺氮的金属，咪唑环的π氮和去质子化的羰基氧和完整他的配体采用了盐桥的二齿结合基序，配位在金属与两个羧酸氧。也有证据表明构象可以维持去质子化的His配位，但完整的His配体采用更规范的结构，与胺氮和π氮处的金属原子[ Nα，Nπ，CO – ] [ ñ α，N π] gtgg。对于两种金属化物质，理论上的B3LYP，B3P86和B3LYP-GD3BJ水平似乎比MP2（full）水平更准确地描述了主要两性离子物质的相对稳定性。
更新日期：2020-12-10
中文翻译：
组氨酸二聚体结合的锌和镉阳离子的IRMPD光谱学和理论结构研究
金属化的气相结构，由去质子化的和完整的组氨酸（His）配体组成，产生M（His-H）（His）+，其中M = Zn和Cd，使用来自自由电子激光（FEL）的光通过红外多光子离解（IRMPD）作用光谱进行了检查。同时，量子化学计算为每种配合物确定了几种低能异构体。使用锌和镉配合物的6-311 + G（d，p）和def2-TZVP基集分别将实验作用谱与在B3LYP理论水平计算的线性谱进行比较。对于Zn和Cd物种，确定的分配都因相对能的冲突而变得复杂，这些相对能在B3LYP，B3LYP-GD3BJ，B3P86和MP2（full）水平下计算。两种物种的光谱比较表明，主要构象[ Nα，Nπ，CO – ] [CO 2 –]（N π ħ +），具有去质子化的他的螯合剂在胺氮的金属，咪唑环的π氮和去质子化的羰基氧和完整他的配体采用了盐桥的二齿结合基序，配位在金属与两个羧酸氧。也有证据表明构象可以维持去质子化的His配位，但完整的His配体采用更规范的结构，与胺氮和π氮处的金属原子[ Nα，Nπ，CO – ] [ ñ α，N π] gtgg。对于两种金属化物质，理论上的B3LYP，B3P86和B3LYP-GD3BJ水平似乎比MP2（full）水平更准确地描述了主要两性离子物质的相对稳定性。
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