Intramolecular[2+2]photocycloaddition is a reliable way to synthesize high-strained cyclobutylcontaining structures for high-value chemicals.Here we propose a photosensitized dimer of methyl cyclopentadiene(DMCPD)intr...Intramolecular[2+2]photocycloaddition is a reliable way to synthesize high-strained cyclobutylcontaining structures for high-value chemicals.Here we propose a photosensitized dimer of methyl cyclopentadiene(DMCPD)intramolecular[2+2]cycloaddition to synthesize an intriguing liquid caged fuel,namely 3,8-dimethylpentacyclic[5.3.0.0^(2,5).0^(3,9).0^(4.8)]decane(MPCD),with two four-membered rings,four five-membered rings and two methyl branched chains.The reaction conditions are optimized to obtain a high DMCPD conversion of 80.95%as well as a high MPCD selectivity of 74.19%.Based on the quenching experiment and low-temperature phosphorescence test,intramolecular[2+2]photocycloaddition complies with the Dexter triplet-energy-transfer mechanism,which is essentially double electron exchange between excited photosensitizer and DMCPD.Through kinetic studies,the reaction order(α=1)and the reaction kinetic equation related to light intensity and DMCPD concentration are obtained.MPCD has excellent physicochemical properties,with a high density of 0.964 g·cm^(-3),high net heat of combustion of 42.63 MJ·kg^(-1),relatively low kinetic viscosity of 25.03 mm^(2)·s^(-1)at(20℃),and high specific impulse of 328.19 s.展开更多
基金support from the National Natural Science Foundation of China(22222808,22408272,U24A20547)the China National Postdoctoral Program for Innovative Talents(BX20240251)+3 种基金the Natural Science Foundation of Tianjin(24JCQNJC01820)the China Postdoctoral Science Foundation(2023M742592)the Aeronautical Science Foundation of China(2023Z073048003)the Haihe Laboratory of Sustainable Chemical Transformations。
文摘Intramolecular[2+2]photocycloaddition is a reliable way to synthesize high-strained cyclobutylcontaining structures for high-value chemicals.Here we propose a photosensitized dimer of methyl cyclopentadiene(DMCPD)intramolecular[2+2]cycloaddition to synthesize an intriguing liquid caged fuel,namely 3,8-dimethylpentacyclic[5.3.0.0^(2,5).0^(3,9).0^(4.8)]decane(MPCD),with two four-membered rings,four five-membered rings and two methyl branched chains.The reaction conditions are optimized to obtain a high DMCPD conversion of 80.95%as well as a high MPCD selectivity of 74.19%.Based on the quenching experiment and low-temperature phosphorescence test,intramolecular[2+2]photocycloaddition complies with the Dexter triplet-energy-transfer mechanism,which is essentially double electron exchange between excited photosensitizer and DMCPD.Through kinetic studies,the reaction order(α=1)and the reaction kinetic equation related to light intensity and DMCPD concentration are obtained.MPCD has excellent physicochemical properties,with a high density of 0.964 g·cm^(-3),high net heat of combustion of 42.63 MJ·kg^(-1),relatively low kinetic viscosity of 25.03 mm^(2)·s^(-1)at(20℃),and high specific impulse of 328.19 s.
