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Li JR, Xu LP, Jiang HM, Wang FQ, Xie J, Man WL, Wang Q, Zhuo S, Lau TC. Oxidation of Hypophosphorous Acid by a Ruthenium(VI) Nitrido Complex in Aqueous Acidic Solution. Evidence for a Proton-Coupled N-Atom Transfer Mechanism. Inorg Chem 2022; 61:10567-10574. [PMID: 35748889 DOI: 10.1021/acs.inorgchem.2c01627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The oxidation of hypophosphorous acid (H3PO2) by a ruthenium(VI) nitrido complex, [(L)RuVI(N)(OH2)]+ (RuVIN; L = N,N'-bis(salicylidene)-o-cyclohexyldiamine dianion), has been studied in aqueous acidic solutions at pH 0-2.50. The reaction has the following stoichiometry: 2[(L)RuVI(N)(OH2)]+ + 3H3PO2 + H2O → 2[(L)RuIII(NH2P(OH)2)(OH2)]+ + H3PO3. The pseudo-first-order rate constant, kobs, depends linearly on [H3PO2], and the second-order rate constant k2 depends on [H+] according to the relationship k2 = k[H+]/([H+] + Ka), where k is the rate constant for the oxidation of H3PO2 molecule and Ka is the dissociation constant of H3PO2. At 298.0 K and I = 1.0 M, k = (2.04 ± 0.19) × 10-2 M-1 s-1 and Ka = (6.38 ± 0.63) × 10-2 M. A kinetic isotope effect (KIE) of 2.9 ± 0.1 was obtained when kinetic studies were carried out with D3PO2 at pH 1.16, suggesting P-H bond cleavage in the rate-determining step. On the other hand, when the kinetics were determined in D2O, an inverse KIE of 0.21 ± 0.03 (H3PO2 in H2O vs H3PO2 in D2O) was found. On the basis of experimental results and DFT calculations, the proposed mechanism involves an acid-catalyzed tautomerization of H2P(O)(OH) to HP(OH)2; the latter molecule is the reacting species which reacts with RuVIN via a proton-coupled N-atom transfer pathway.
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Affiliation(s)
- Ji-Rui Li
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255000, People's Republic of China
| | - Li-Ping Xu
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255000, People's Republic of China
| | - Hui-Mei Jiang
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255000, People's Republic of China
| | - Feng-Qin Wang
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255000, People's Republic of China
| | - Jianhui Xie
- Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009, People's Republic of China
| | - Wai-Lun Man
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong 999077, People's Republic of China
| | - Qian Wang
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255000, People's Republic of China
| | - Shuping Zhuo
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255000, People's Republic of China
| | - Tai-Chu Lau
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong 999077, People's Republic of China
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Wang Q, Zhao HY, Man WL, Lam WWY, Lau KC, Lau TC. Kinetics and Mechanism of the Reaction of a Ruthenium(VI) Nitrido Complex with HSO3 (-) and SO3 (2-) in Aqueous Solution. Chemistry 2016; 22:10754-8. [PMID: 27246832 DOI: 10.1002/chem.201601848] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Indexed: 11/10/2022]
Abstract
The kinetics and mechanism of the reaction of S(IV) (SO3 (2-) +HSO3 (-) ) with a ruthenium(VI) nitrido complex, [(L)Ru(VI) (N)(OH2 )](+) (Ru(VI) N, L=N,N'-bis(salicylidene)-o-cyclohexyldiamine dianion), in aqueous acidic solutions are reported. The kinetic results are consistent with parallel pathways involving oxidation of HSO3 (-) and SO3 (2-) by Ru(VI) N. A deuterium isotope effect of 4.7 is observed in the HSO3 (-) pathway. Based on experimental results and DFT calculations the proposed mechanism involves concerted N-S bond formation (partial N-atom transfer) between Ru(VI) N and HSO3 (-) and H(+) transfer from HSO3 (-) to a H2 O molecule.
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Affiliation(s)
- Qian Wang
- Department of Biology and Chemistry and Institute of Molecular Functional Materials, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, China
| | - Hong Yan Zhao
- Department of Biology and Chemistry and Institute of Molecular Functional Materials, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, China
| | - Wai-Lun Man
- Department of Biology and Chemistry and Institute of Molecular Functional Materials, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, China
| | - William W Y Lam
- Department of Biology and Chemistry and Institute of Molecular Functional Materials, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, China
| | - Kai-Chung Lau
- Department of Biology and Chemistry and Institute of Molecular Functional Materials, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, China.
| | - Tai-Chu Lau
- Department of Biology and Chemistry and Institute of Molecular Functional Materials, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, China.
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Man WL, Xie J, Lo PK, Lam WWY, Yiu SM, Lau KC, Lau TC. Functionalization of Alkynes by a (Salen)ruthenium(VI) Nitrido Complex. Angew Chem Int Ed Engl 2014; 53:8463-6. [DOI: 10.1002/anie.201404421] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Indexed: 11/07/2022]
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