科研之友
微信
新浪微博
Facebook
分享链接
摘要
A p-quinodimethane (p-QDM)-bridged porphyrin dimer 1 has been prepared for the first time. An unexpected Michael addition reaction took place when we attempted to synthesize compound 1 by reaction of the cross-conjugated keto-linked porphyrin dimers 8a and 8b with alkynyl/aryl Grignard reagents. Alternatively, compound 1 could be successfully prepared by intramolecular Friedel-Crafts alkylation of the diol-linked porphyrin dimer 14 with concomitant oxidation in air. Compound 1 shows intense one-photon absorption (OPA, (max)=955nm, epsilon=45400M(-1)cm(-1)) and a large two-photon absorption (TPA) cross-section (sigma((2))(max)=2080GM at 1800nm) in the near-infrared (NIR) region due to its extended -conjugation and quinoidal character. It also exhibits a short singlet excited-state lifetime of 25ps. The cyclic voltammogram of 1 displays multiple redox waves with a small electrochemical energy gap of 0.86eV. The ground-state geometry, electronic structure, and optical properties of 1 have been further studied by density functional theory (DFT) calculations and compared with those of the keto-linked dimer 8b. This research has revealed that incorporation of a p-QDM unit into the porphyrin framework had a significant impact on its optical and electronic properties, leading to a novel NIR OPA and TPA chromophore.
- 出版日期2013-12-2
