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Sulfated Carbon Quantum Dots as Efficient Visible‐Light Switchable Acid Catalysts for Room‐Temperature Ring‐Opening Reactions
Author(s) -
Li Haitao,
Sun Chenghua,
Ali Muataz,
Zhou Fengling,
Zhang Xinyi,
MacFarlane Douglas R.
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201501698
Subject(s) - catalysis , chemistry , photoexcitation , photochemistry , quantum yield , carbon fibers , quantum dot , methanol , acid catalysis , ring (chemistry) , nanotechnology , organic chemistry , materials science , fluorescence , excited state , physics , quantum mechanics , composite number , nuclear physics , composite material
Acid catalytic processes play a classic and important role in modern organic synthesis. How well the acid can be controlled often plays the key role in the controllable synthesis of the products with high conversion yield and selectivity. The preparation of a novel, photo‐switchable solid‐acid catalyst based on carbon quantum dots is described. The carbon quantum dots are decorated with small amounts of hydrogensulfate groups and thus exhibit a photogenerated acidity that produces a highly efficient acid catalysis of the ring opening of epoxides with methanol and other primary alcohols. This reversible, light‐switchable acidity is shown to be due to photoexcitation and charge separation in the carbon quantum dots, which create an electron withdrawing effect from the acidic groups. The catalyst is easily separated by filtration, and we demonstrate multiple cycles of its recovery and reuse.