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Preparation, electrochemical and spectral properties of N-methylated pyridylethynyl porphyrins.
Lin, Ching-Yao; Chuang, Li-Chieh; Yang, Ya-Fen; Lin, Chun-Ling; Kao, Hsien-Chang; Wang, Wen-Jwu.
Affiliation
  • Lin CY; Department of Applied Chemistry, National Chi Nan University, 302 University Road, Puli, Nantou Hsien 545, Taiwan. cyl@ncnu.edu.tw.
Dalton Trans ; (3): 456-62, 2004 Feb 07.
Article in En | MEDLINE | ID: mdl-15252554
A new series of electron-deficient porphyrins were prepared by attaching one or two N-methylated 2-, 3- or 4-pyridylethynyl groups to the 10,20-meso positions of (5,15-biphenylporphinato)zinc(II). Electrochemical studies showed significant changes in the reduction potentials of these porphyrins, and N-methyl-2-pyridylethyne is the strongest electron-withdrawing substituent in the series. UV-visible spectra demonstrated largely red-shifted absorptions, and N-methyl-4-pyridylethyne has the greatest impact to the porphyrin absorptions. Electrochemical, UV-visible and EPR results concluded that porphyrins Zn2 and Zn6 reversibly undergo two one-electron porphyrin-ring reductions to their anion radicals then dianions. The first reductions of porphyrins Zn1, Zn3, Zn4 and Zn5 were irreversible one-electron transfer processes. The instability of these reduction products was suggested to result from the eletrophilic attacks at the substituents.
Subject(s)
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Collection: 01-internacional Database: MEDLINE Main subject: Zinc / Metalloporphyrins Language: En Journal: Dalton Trans Journal subject: QUIMICA Year: 2004 Document type: Article Affiliation country: Country of publication:
Search on Google
Collection: 01-internacional Database: MEDLINE Main subject: Zinc / Metalloporphyrins Language: En Journal: Dalton Trans Journal subject: QUIMICA Year: 2004 Document type: Article Affiliation country: Country of publication: