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Sakashita R, Oka Y, Akimaru H, Kesavan PE, Ishida M, Toganoh M, Ishizuka T, Mori S, Furuta H. Tautomerism-Induced Cis-Trans Isomerization of Pyridylethenyl N-Confused Porphyrin. J Org Chem 2017; 82:8686-8696. [PMID: 28745048 DOI: 10.1021/acs.joc.7b01770] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Pyridylethenyl-substituted N-confused porphyrins (NCPs) were synthesized, and their cis-trans isomerization was studied. Among four possible isomers, trans-3H and cis-2H types of structures, of which aromaticity and absorption/emission properties differ largely, were isolated. The cis-isomer was largely stabilized by the intramolecular hydrogen bonding between the pyrrolic-NH and the pyridinic-N in the vicinity. The thermal cis-trans isomerization proceeded even at 30 °C, which was significantly accelerated by the pyridine added to the system. The kinetic studies revealed that the isomerization reaction was second-order and the activation energy of the thermal isomerization from cis to trans isomer was ΔG0⧧cis→trans = 35.7 kcal/mol at 298 K, which is significantly smaller than that of Ni complex (42.3 kcal/mol). An intermolecular proton transfer induced cis-trans isomerization mechanism was proposed.
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Affiliation(s)
- Ryuichi Sakashita
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University , Fukuoka 819-0395, Japan
| | - Yasutaka Oka
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University , Fukuoka 819-0395, Japan
| | - Hisanori Akimaru
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University , Fukuoka 819-0395, Japan
| | - Praseetha E Kesavan
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University , Fukuoka 819-0395, Japan
| | - Masatoshi Ishida
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University , Fukuoka 819-0395, Japan
| | - Motoki Toganoh
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University , Fukuoka 819-0395, Japan
| | - Tomoya Ishizuka
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba , Tsukuba 305-8571, Japan
| | - Shigeki Mori
- Advanced Research Support Center, Ehime University , Matsuyama 790-8577, Japan
| | - Hiroyuki Furuta
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University , Fukuoka 819-0395, Japan
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Arai T, Shinozaki Y, Ishida Y, Aizawa F. Photochemical Behavior of 2’-Hydroxychalcone Derivatives Having Pyridyl and Quinolyl Groups. HETEROCYCLES 2016. [DOI: 10.3987/com-15-s(t)43] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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