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Zhao X, Xu W, Chen X, Lin S, Li X, He L, Liao X, Ye G. A comparison of hydrogen abstraction reaction between allyl-type monomers with thioxanthone-based photoinitiators without amine synergists. Front Chem 2022; 10:967836. [PMID: 36118315 PMCID: PMC9478512 DOI: 10.3389/fchem.2022.967836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 07/25/2022] [Indexed: 11/18/2022] Open
Abstract
The photodriven radical-mediated [3 + 2] cyclization reaction was found to yield polymers efficiently without being hindered by degradative chain transfer. The first reaction is a hydrogen abstraction process in which one hydrogen atom migrates from the α-methylene group of an allyl monomer to the triplet state (or fragments) of the photoinitiator, thus yielding primary allyl radicals as primary radicals and then begins chain propagation via a 3 + 2 cyclization reaction. Allyl ether monomers were found to be significantly higher than other allyl monomers even with the absence of amine-like synergists. In order to clarify the procedure of the hydrogen abstraction mechanism, we used four allyl-type monomers as hydrogen donors and three thioxanthone photoinitiators as hydrogen acceptors by the quantum chemistry method in terms of geometry and energy. The results were interpreted with transition-state theory and the interaction/deformation model. Then, the tunneling factors of hydrogen abstraction reactions were also investigated by Eckart’s correction. The results show allyl ether systems are more reactive than other allyl systems, and it would provide us with new insights into these hydrogen abstractions.
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Affiliation(s)
- Xiaotian Zhao
- Department of Pharmacy, Chengdu Second Peoples Hospital, Chengdu, China
| | - Wen Xu
- Department of Dermatology, Chengdu Second Peoples Hospital, Chengdu, China
| | - Xi Chen
- Department of Pharmacy, Chengdu Second Peoples Hospital, Chengdu, China
| | - Shibo Lin
- Department of Pharmacy, Chengdu Second Peoples Hospital, Chengdu, China
| | - Xuanhao Li
- Department of Pharmacy, Chengdu Second Peoples Hospital, Chengdu, China
| | - Lihui He
- Department of Pharmacy, Chengdu Second Peoples Hospital, Chengdu, China
| | - Xu Liao
- Department of Pharmacy, Chengdu Second Peoples Hospital, Chengdu, China
| | - Guodong Ye
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, the NMPA and State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
- *Correspondence: Guodong Ye,
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Zhao X, Huang W, Lin S, Chen X, Guo X, Zou D, Ye G. Density Functional Theory Guide for an Allyl Monomer Polymerization Mechanism: Photoinduced Radical-Mediated [3 + 2] Cyclization. ACS OMEGA 2021; 6:15608-15616. [PMID: 34179605 PMCID: PMC8223207 DOI: 10.1021/acsomega.1c00165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 05/26/2021] [Indexed: 06/13/2023]
Abstract
Polymerization of allyl ether monomers has previously been considered a free-radical addition polymerization mechanism, but it is difficult to achieve because of the high electron density of their double bond. To interpret the mechanism of photopolymerization, we therefore proposed a radical-mediated cyclization (RMC) reaction, which has been validated by results from quantum chemistry calculations and real-time infrared observation. Our RMC reaction begins with the radical abstracting one allylic hydrogen atom from the methylene group of allyl ether to generate an allyl ether radical with a delocalized π3 3 bond. Then, the radical reacts with the double bond of a second allyl ether molecule to form a five-membered cyclopentane-like ring (CP) radical. The CP radical abstracts a hydrogen atom from a third ether molecule. At last, a new allyl ether radical is generated and the next circulation as chain propagation begins. The distortion/interaction model was employed to explore the transient state of reaction, and real-time infrared was chosen to clarify the RMC reaction mechanism initiated by different photoinitiators. These results demonstrated that the RMC mechanism can give new insights into these fundamental processes.
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Affiliation(s)
- Xiaotian Zhao
- Chengdu
Second Peoples Hospital, Chengdu 610017, P.R. China
| | - Wanqiu Huang
- Guangdong
Pharmaceutical University, Guangzhou 510006, P.R. China
| | - Shibo Lin
- Chengdu
Second Peoples Hospital, Chengdu 610017, P.R. China
| | - Xi Chen
- Chengdu
Second Peoples Hospital, Chengdu 610017, P.R. China
| | - Xirui Guo
- Chengdu
Second Peoples Hospital, Chengdu 610017, P.R. China
| | - Dehong Zou
- Chengdu
Second Peoples Hospital, Chengdu 610017, P.R. China
| | - Guodong Ye
- The
Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou 510799, P.R. China
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Huang W, Lin R, Zhao X, Li Q, Huang Y, Ye G. How does a weak interaction change from a reactive complex to a saddle point in a reaction? COMPUT THEOR CHEM 2020. [DOI: 10.1016/j.comptc.2019.112640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Zhao X, Huang W, Song D, Lin R, Huang H, Huang J, Wu B, Huang Y, Ye G. The hydrogen transfer reaction between the substance of triplet state thioxanthone and alkane with sp 3 hybridization hydrogen. J Mol Model 2020; 26:56. [PMID: 32048049 DOI: 10.1007/s00894-020-4300-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 01/17/2020] [Indexed: 11/30/2022]
Abstract
The activation or functionalization of the saturated C-H is an extremely active field at present. We have explored the triplet state thioxanthone in reactivity of the hydrogen transfer reaction between donors and acceptors. In our works, two donors with quasi-inert sp3 C-H of skipped diene (3,6-nonadiene) and cyclic acetals (benzodioxole) reacted with type II photoinitiators (triplet state of thioxanthone series, TXs) as acceptors are investigated. The excited energies of TXs were obtained by time-dependent density functional theory (TD-DFT). TXs show obvious photosensibility based on their low reorganization energies (< 60 kcal mol-1). The isoentropy reactions had linear geometries of transition state (TS). The distortion/interaction model was used to probe the existence of interaction between acceptors and donors in saddle point. The distortion energy and activation barrier of benzodioxole are much higher than those of the corresponding 3,6-nonadiene. The lower bond dissociation energy noticeably affect the transition state. The reaction of triplet state of TXs with skipped dienes were found to have an anomalous low tunneling factors by using Wigner correction and early transition state by using the bond-energy-bond-order method. The triplet state of TXs photoinitiator can induced the hydrogen abstraction from saturated cyclic acetals and the skipped alkadienes. The hydrogen abstraction experiment are confirmed by UV and real-time FTIR.
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Affiliation(s)
- Xiaotian Zhao
- Key Laboratory of Molecular Target & Clinical Pharmacology, and School of Pharmaceutical Sciences, the Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, 511436, People's Republic of China
| | - Wanqiu Huang
- Key Laboratory of Molecular Target & Clinical Pharmacology, and School of Pharmaceutical Sciences, the Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, 511436, People's Republic of China
| | - Dandan Song
- Key Laboratory of Molecular Target & Clinical Pharmacology, and School of Pharmaceutical Sciences, the Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, 511436, People's Republic of China
| | - Runxing Lin
- Key Laboratory of Molecular Target & Clinical Pharmacology, and School of Pharmaceutical Sciences, the Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, 511436, People's Republic of China
| | - Hong Huang
- Key Laboratory of Molecular Target & Clinical Pharmacology, and School of Pharmaceutical Sciences, the Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, 511436, People's Republic of China
| | - Junjun Huang
- Key Laboratory of Molecular Target & Clinical Pharmacology, and School of Pharmaceutical Sciences, the Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, 511436, People's Republic of China
| | - Bo Wu
- Key Laboratory of Molecular Target & Clinical Pharmacology, and School of Pharmaceutical Sciences, the Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, 511436, People's Republic of China
| | - Yugang Huang
- Key Laboratory of Molecular Target & Clinical Pharmacology, and School of Pharmaceutical Sciences, the Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, 511436, People's Republic of China
| | - Guodong Ye
- Key Laboratory of Molecular Target & Clinical Pharmacology, and School of Pharmaceutical Sciences, the Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, 511436, People's Republic of China.
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