We herein report the reactivity and regioselectivity of 2-pyrenyl as a coupling unit in Scholl reactions.On the basis of the Scholl reactions of hexaarylbenzene substrates,we have found that pyrenyl units are preferab...We herein report the reactivity and regioselectivity of 2-pyrenyl as a coupling unit in Scholl reactions.On the basis of the Scholl reactions of hexaarylbenzene substrates,we have found that pyrenyl units are preferably oxidized over naphthyl and phenyl units under appropriate Scholl reaction conditions,allowing divergent synthesis through a highly controllable intramolecular coupling sequence.We find that the C1 and C3 positions of the 2-pyrenyl unit are the favorable sites for intramolecular coupling while C4 is not reactive to allow further coupling.The reactivity and regioselectivity pattern can be explained by the spin density distribution,which shows that carbon-carbon bonds preferably form at sites with higher positive spin density.Guided by these findings,we successfully synthesized a double helicene and a sextuple helicene through the controlled Scholl reactions of 2-pyrenyl units.展开更多
Fast photogenerated charge migration is crucial for the improvement of photocatalytic performance,but its deliberate modulation is difficult.This work presents two Zr-based metal–organic framework catalysts,GDUT-8 an...Fast photogenerated charge migration is crucial for the improvement of photocatalytic performance,but its deliberate modulation is difficult.This work presents two Zr-based metal–organic framework catalysts,GDUT-8 and GDUT-8-Ox,for photocatalytic CO_(2)reduction.Specifically,thiophene pendants in GDUT-8 were coupled covalently via Scholl reaction to give GDUT-8-Ox,a catalyst with at least two orders of magnitude(up to 6.1×10^(−3)S cm^(−1))enhanced conductivity and faster transport of photogenerated carriers during photocatalysis.Furthermore,from GDUT-8 to GDUT-8-Ox,stronger ligand-to-cluster charge transfer with pronounced light absorption extension was observed.As a result,GDUT-8-Ox exhibited the highest photocatalytic CO_(2)-to-HCOO−conversion rate(1725μmol g^(−1)h^(−1))to date,in the absence of photosensitizer,as well as turnover number,turnover frequency,and quantum efficiency much higher than GDUT-8.This work presents an unprecedented strategy to accelerate the photogenerated carrier transport of photocatalysts.展开更多
A novel ketone-functionalized aromatic saddle consisting of 72 sp^2 carbon atoms is successfully synthesized and unambiguously identified with X-ray crystallography.It can,in principle,be used as a building block for ...A novel ketone-functionalized aromatic saddle consisting of 72 sp^2 carbon atoms is successfully synthesized and unambiguously identified with X-ray crystallography.It can,in principle,be used as a building block for synthesis of negatively curved carbon nanobelts and for a bottom-up approach to negatively curved carbon allotropes.展开更多
基金supported by the University Grants Committee(Hong Kong)through a Research Matching Grant,Deutsche Forschungsgemeinschaft(DFG)through the research training group“Template-Designed Organic Electronics(TIDE)”(RTG 2591)the U.S.Department of Energy(DOE),Office of Science,Basic Energy Sciences(BES),Materials Sciences and Engineering Division under contract no.DE-AC02-05-CH11231(Nanomachine program KC1203)and contract no.DE-SC0023105.
文摘We herein report the reactivity and regioselectivity of 2-pyrenyl as a coupling unit in Scholl reactions.On the basis of the Scholl reactions of hexaarylbenzene substrates,we have found that pyrenyl units are preferably oxidized over naphthyl and phenyl units under appropriate Scholl reaction conditions,allowing divergent synthesis through a highly controllable intramolecular coupling sequence.We find that the C1 and C3 positions of the 2-pyrenyl unit are the favorable sites for intramolecular coupling while C4 is not reactive to allow further coupling.The reactivity and regioselectivity pattern can be explained by the spin density distribution,which shows that carbon-carbon bonds preferably form at sites with higher positive spin density.Guided by these findings,we successfully synthesized a double helicene and a sextuple helicene through the controlled Scholl reactions of 2-pyrenyl units.
基金supported by the China Postdoctoral Science Foundation(2021M700877 and no.15 Special Fund(In-Station),2022T150143)the National Natural Science Foundation of China(nos.22201046,21871061,and 21871141)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01Z032).
文摘Fast photogenerated charge migration is crucial for the improvement of photocatalytic performance,but its deliberate modulation is difficult.This work presents two Zr-based metal–organic framework catalysts,GDUT-8 and GDUT-8-Ox,for photocatalytic CO_(2)reduction.Specifically,thiophene pendants in GDUT-8 were coupled covalently via Scholl reaction to give GDUT-8-Ox,a catalyst with at least two orders of magnitude(up to 6.1×10^(−3)S cm^(−1))enhanced conductivity and faster transport of photogenerated carriers during photocatalysis.Furthermore,from GDUT-8 to GDUT-8-Ox,stronger ligand-to-cluster charge transfer with pronounced light absorption extension was observed.As a result,GDUT-8-Ox exhibited the highest photocatalytic CO_(2)-to-HCOO−conversion rate(1725μmol g^(−1)h^(−1))to date,in the absence of photosensitizer,as well as turnover number,turnover frequency,and quantum efficiency much higher than GDUT-8.This work presents an unprecedented strategy to accelerate the photogenerated carrier transport of photocatalysts.
基金supported by the Research Grants Council of Hong Kong (No. GRF 14300218)
文摘A novel ketone-functionalized aromatic saddle consisting of 72 sp^2 carbon atoms is successfully synthesized and unambiguously identified with X-ray crystallography.It can,in principle,be used as a building block for synthesis of negatively curved carbon nanobelts and for a bottom-up approach to negatively curved carbon allotropes.
