Alkenes are ubiquitous,and the difunctionalization of alkenes represents one of the most practical approaches for the construction of value-added compounds.Dicarbonylation of alkenes provides direct access to value-ad...Alkenes are ubiquitous,and the difunctionalization of alkenes represents one of the most practical approaches for the construction of value-added compounds.Dicarbonylation of alkenes provides direct access to value-added 1,4-dicarbonyl compounds.However,selectivity control for unsymmetric 1,2-dicarbonylation is of great challenge.We herein describe NHCs and photocatalysis co-catalyzed three-component radical 1,2-dicarbonylation of alkenes by distinguishing two carbonyl groups,providing structurally diversified 1,4-diketones.Distinct properties of acyl radical and NHCs-stabilized ketyl radical contributed to selectivity control.Acyl radicals are rapidly added to alkenes delivering alkyl radicals,which undergo subsequent radicalradical cross-coupling with NHCs-stabilized ketyl-type radicals,affording 1,2-dicarbonylation products.This transformation features mild reaction conditions,broad substrate scope,and excellent selectivity,providing a general and practical approach for the dicarbonylation of olefins.展开更多
采用改进Stober法-化学沉淀法制备了Ni(OH)_(2)/氮掺杂空心碳球复合材料(Ni(OH)_(2)/NHCS)。通过X射线衍射(XRD)、透射电镜(TEM)和N 2吸附-脱附等手段对复合材料进行表征和分析,并采用电化学工作站对复合材料的电化学性能进行测试。研...采用改进Stober法-化学沉淀法制备了Ni(OH)_(2)/氮掺杂空心碳球复合材料(Ni(OH)_(2)/NHCS)。通过X射线衍射(XRD)、透射电镜(TEM)和N 2吸附-脱附等手段对复合材料进行表征和分析,并采用电化学工作站对复合材料的电化学性能进行测试。研究结果表明:相比于纯Ni(OH)_(2)而言,NHCS有效抑制了Ni(OH)_(2)的聚集,从而提高了活性材料的利用率。同时,复合材料的中空结构有利于电解质离子的渗入而缩短电解质离子的传输路径,且降低界面电阻,从而有效提高了复合材料Ni(OH)_(2)/NHCS的电化学性能。Ni(OH)_(2)/NHCS在2 M KOH电解质中,电流密度为0.5 A g^(-1)时可表现出1085 F g^(-1)的高比电容。展开更多
The potential for degradation of five nitrogenous heterocyclic compounds（NHCs）, i.e.,imidazole, pyridine, indole, quinoline, and carbazole, was investigated under anoxic conditions with acclimated activated sludge. ...The potential for degradation of five nitrogenous heterocyclic compounds（NHCs）, i.e.,imidazole, pyridine, indole, quinoline, and carbazole, was investigated under anoxic conditions with acclimated activated sludge. Results showed that NHCs with initial concentration of 50 mg/L could be completely degraded within 60 hr. The degradation of five NHCs was dependent upon the chemical structures with the following sequence：imidazole 〉 pyridine 〉 indole 〉 quinoline 〉 carbazole in terms of their degradation rates.Quantitative structure-biodegradability relationship studies of the five NHCs showed that the anoxic degradation rates were correlated well with highest occupied molecular orbital.Additionally, the active sites of NHCs identified by calculation were confirmed by analysis of intermediates using gas chromatography and mass spectrometry.展开更多
基金supported by the National Natural Science Foundation of China (22001157,21831002,22193012)the Ten Thousand Talents Program+2 种基金the Fundamental Research Funds for the Central Universities (2412022QD016,2412021QD007)the Natural Science Foundation of Jilin Province (YDZJ202201ZYTS338)the Natural Science Foundation of Shaanxi Province (2020JQ-404)
文摘Alkenes are ubiquitous,and the difunctionalization of alkenes represents one of the most practical approaches for the construction of value-added compounds.Dicarbonylation of alkenes provides direct access to value-added 1,4-dicarbonyl compounds.However,selectivity control for unsymmetric 1,2-dicarbonylation is of great challenge.We herein describe NHCs and photocatalysis co-catalyzed three-component radical 1,2-dicarbonylation of alkenes by distinguishing two carbonyl groups,providing structurally diversified 1,4-diketones.Distinct properties of acyl radical and NHCs-stabilized ketyl radical contributed to selectivity control.Acyl radicals are rapidly added to alkenes delivering alkyl radicals,which undergo subsequent radicalradical cross-coupling with NHCs-stabilized ketyl-type radicals,affording 1,2-dicarbonylation products.This transformation features mild reaction conditions,broad substrate scope,and excellent selectivity,providing a general and practical approach for the dicarbonylation of olefins.
文摘采用改进Stober法-化学沉淀法制备了Ni(OH)_(2)/氮掺杂空心碳球复合材料(Ni(OH)_(2)/NHCS)。通过X射线衍射(XRD)、透射电镜(TEM)和N 2吸附-脱附等手段对复合材料进行表征和分析,并采用电化学工作站对复合材料的电化学性能进行测试。研究结果表明:相比于纯Ni(OH)_(2)而言,NHCS有效抑制了Ni(OH)_(2)的聚集,从而提高了活性材料的利用率。同时,复合材料的中空结构有利于电解质离子的渗入而缩短电解质离子的传输路径,且降低界面电阻,从而有效提高了复合材料Ni(OH)_(2)/NHCS的电化学性能。Ni(OH)_(2)/NHCS在2 M KOH电解质中,电流密度为0.5 A g^(-1)时可表现出1085 F g^(-1)的高比电容。
基金supported by the Harbin Institute of Technology (No. 2013DX10)the Sino-Dutch Research Program (No. zhmhgfs2011-001)the Sino-American Coal Chemical Industry Program (No. ZMAGZ 2011001)
文摘The potential for degradation of five nitrogenous heterocyclic compounds（NHCs）, i.e.,imidazole, pyridine, indole, quinoline, and carbazole, was investigated under anoxic conditions with acclimated activated sludge. Results showed that NHCs with initial concentration of 50 mg/L could be completely degraded within 60 hr. The degradation of five NHCs was dependent upon the chemical structures with the following sequence：imidazole 〉 pyridine 〉 indole 〉 quinoline 〉 carbazole in terms of their degradation rates.Quantitative structure-biodegradability relationship studies of the five NHCs showed that the anoxic degradation rates were correlated well with highest occupied molecular orbital.Additionally, the active sites of NHCs identified by calculation were confirmed by analysis of intermediates using gas chromatography and mass spectrometry.
