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Cho YI, Durgaprasad G, Rose MJ. CNS and CNP Iron(II) Mono-Iron Hydrogenase (Hmd) Mimics: Role of Deprotonated Methylene(acyl) and the trans-Acyl Site in H 2 Heterolysis. Inorg Chem 2019; 58:12689-12699. [PMID: 31497945 DOI: 10.1021/acs.inorgchem.9b01530] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report syntheses and H2 activation involving model complexes of mono-iron hydrogenase (Hmd) derived from acyl-containing pincer ligand precursors bearing thioether (CNSPre) or phosphine (CNPPre) donor sets. Both complexes feature pseudo-octahedral iron(II) dicarbonyl units. While the CNS pincer adopts the expected mer-CNS (pincer) geometry, the CNP ligand unexpectedly adopts the fac-CNP coordination geometry. Both complexes exhibit surprisingly acidic methylene C-H bond (reversibly de/protonated by a bulky phenolate), which affords a putative dearomatized pyridinate-bound intermediate. Such base treatment of Fe-CNS also results in deligation of the thioether sulfur donor, generating an open coordination site trans from the acyl unit. In contrast, Fe-CNP maintains a CO ligand trans from the acyl site both in the parent and dearomatized complexes (the -PPh2 donor is cis to acyl). The dearomatized mer-Fe-CNS was competent for H2 activation (5 atm D2(g) plus phenolate as base), which is attributed to both the basic site on the ligand framework and the open coordination site trans to the acyl donor. In contrast, the dearomatized fac-Fe-CNP was not competent for H2 activation, which is ascribed to the blocked coordination site trans from acyl (occupied by CO ligand). These results highlight the importance of both (i) the open coordination site trans to the organometallic acyl donor and (ii) a pendant base in the enzyme active site.
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Affiliation(s)
- Yae In Cho
- Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Gummadi Durgaprasad
- Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States
| | - Michael J Rose
- Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States
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Song LC, Zhu L, Hu FQ, Wang YX. Studies on Chemical Reactivity and Electrocatalysis of Two Acylmethyl(hydroxymethyl)pyridine Ligand-Containing [Fe]-Hydrogenase Models (2-COCH2-6-HOCH2C5H3N)Fe(CO)2L (L = η1-SCOMe, η1-2-SC5H4N). Inorg Chem 2017; 56:15216-15230. [DOI: 10.1021/acs.inorgchem.7b02582] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Li-Cheng Song
- Department
of Chemistry, State Key Laboratory of Elemento-Organic Chemistry,
College of Chemistry, and ‡Collaborative Innovation Center of Chemical Science
and Engineering (Tianjin), Nankai University, Tianjin 300071, China
| | - Liang Zhu
- Department
of Chemistry, State Key Laboratory of Elemento-Organic Chemistry,
College of Chemistry, and ‡Collaborative Innovation Center of Chemical Science
and Engineering (Tianjin), Nankai University, Tianjin 300071, China
| | - Fu-Qiang Hu
- Department
of Chemistry, State Key Laboratory of Elemento-Organic Chemistry,
College of Chemistry, and ‡Collaborative Innovation Center of Chemical Science
and Engineering (Tianjin), Nankai University, Tianjin 300071, China
| | - Yong-Xiang Wang
- Department
of Chemistry, State Key Laboratory of Elemento-Organic Chemistry,
College of Chemistry, and ‡Collaborative Innovation Center of Chemical Science
and Engineering (Tianjin), Nankai University, Tianjin 300071, China
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3
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Shi J, Hu B, Chen X, Shang S, Deng D, Sun Y, Shi W, Yang X, Chen D. Synthesis, Reactivity, and Catalytic Transfer Hydrogenation Activity of Ruthenium Complexes Bearing NNN Tridentate Ligands: Influence of the Secondary Coordination Sphere. ACS OMEGA 2017; 2:3406-3416. [PMID: 31457662 PMCID: PMC6641270 DOI: 10.1021/acsomega.7b00410] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 07/03/2017] [Indexed: 05/14/2023]
Abstract
By the introduction of -OH group(s) into different position(s) of 6-(pyridin-2-ylmethyl)-2,2'-bipyridine, several NNN-type ligands were synthesized and then introduced to ruthenium (Ru) centers by reactions with RuCl2(PPh3)3. In the presence of PPh3 or CO, these ruthenium complexes reacted with NH4PF6 in CH2Cl2 or CH3OH to give a series of ionic products 5-9. The reaction of Ru(L2)(PPh3)Cl2 (2) with CO generated a neutral complex [Ru(L2)(CO)Cl2] (10). In the presence of CH3ONa, 10 was further converted into complex [Ru(L2)(HOCH3)(CO)Cl] (11), in which there was a methanol molecule coordinating with ruthenium, as suggested by density functional theory calculations. The catalytic transfer hydrogenation activity of all of these new bifunctional metal-ligand complexes was tested. Dichloride complex 2 exhibits best activity, whereas carbonyl complexes 10 and 11 are efficient for selectively reducing 5-hexen-2-one, suggesting different hydrogenation mechanisms. The results reveal the dramatic influence for the reactivity and catalytic activity of the secondary coordination sphere in transition metal complexes.
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Affiliation(s)
- Jing Shi
- MIIT
Key Laboratory of Critical Materials Technology for New Energy Conversion
and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China
| | - Bowen Hu
- MIIT
Key Laboratory of Critical Materials Technology for New Energy Conversion
and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China
| | - Xiangyang Chen
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, China
- Institute
of Chemistry, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Shu Shang
- MIIT
Key Laboratory of Critical Materials Technology for New Energy Conversion
and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China
| | - Danfeng Deng
- MIIT
Key Laboratory of Critical Materials Technology for New Energy Conversion
and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China
| | - Yanan Sun
- MIIT
Key Laboratory of Critical Materials Technology for New Energy Conversion
and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China
| | - Weiwei Shi
- MIIT
Key Laboratory of Critical Materials Technology for New Energy Conversion
and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China
| | - Xinzheng Yang
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, China
| | - Dafa Chen
- MIIT
Key Laboratory of Critical Materials Technology for New Energy Conversion
and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China
- State
Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China
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