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论文类型：期刊论文

发表时间：2019-01-01

发表刊物：ACS CATALYSIS

收录刊物：SCIE、Scopus

卷号：9

期号：1

页面范围：422-430

ISSN号：2155-5435

关键字：two-photon photocatalysis; metal-organic framework; visible light; coupling reactions; nonlinear optics

摘要：A multiple-photon photochemical process breaks the existing energy limitation of visible-light photo catalysis. Through careful incorporation of both bis(3,5-dicarboxyphenyl)pyridine and bis (3,5-dicarboxyphenyl)-methylpyridinium ligands into a single metal-organic framework (MOF), we report herein photocatalytic C-N and C-C oxidative coupling reactions that evidenced the direct two photon response process. Time-dependent luminescence decay studies demonstrated that the framework reached the same excited state by a two-photon absorption process as that reached via a single-photon absorption process, and the excited state could activate substrates even under NIR-light irradiation. Under 660 nm light-emitting diode (LED) irradiation, both the photooxidative C-N coupling reaction of benzylamine to form benzylidene-1-phenylmethanamine and the C-C coupling reaction between nitromethane and N-phenyltetrahydroisoquinoline were accelerated directly in a heterogeneous manner. Control experiments suggested that minimal byproducts were formed under the NIR-light irradiation compared to those of the UV light catalytic reactions. Importantly, photon intensity-dependent studies exhibited a nonlinear correlation between catalytic efficiency of multivariate MOFs (MTV-MOFs) and photon power intensity, verifying the two photon responsive nature, which indicated that metal-organic framework with high density and ordered photoactive motifs could enhance the two-photon absorption ability, thereby improving photocatalytic efficiency even under LED irradiation.