Synthesis and Photophysical Properties of N-Fused Tetraphenylporphyrin Derivatives: Near-Infrared Organic Dye of [18]Annulenic Compounds

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• 作者：Shinya Ikeda ; Motoki Toganoh ; Shanmugam Easwaramoorthi ; Jong Min Lim ; Dongho Kim ; Hiroyuki Furuta
• 刊名：Journal of Organic Chemistry
• 出版年：2010
• 出版时间：December 17, 2010
• 年：2010
• 卷：75
• 期：24
• 页码：8637-8649
• 全文大小：1283K
• 年卷期：v.75,no.24(December 17, 2010)
• ISSN：1520-6904

文摘

A variety of N-fused porphyrin derivatives were prepared and their photophysical properties were investigated. Although intact N-fused tetraarylporphyrins showed almost no emission, introduction of electron-withdrawing groups such as a nitro group and a cyano group on the macrocycles caused significant refinements in their emission efficiency. Long emission wavelengths (900−1000 nm) as well as fairly large Stokes shifts (1200 cm⁻¹) are exceptionally unique photophysical properties among [18]annulenic compounds, which could be rationalized by the excited state intramolecular proton transfer (ESIPT) process. Relatively weak emission quantum yields (5.0 × 10⁻⁴) and unusually short S₁ state lifetimes (13.5 ps) are in good agreement with the ESIPT process. The solvent and substituent effects on the photophysical properties are also discussed in conjunction with the theoretical studies, where the mesityl groups at the meso-positions play a unique role.