Pinpoint-fluorinated polycyclic aromatic hydrocarbons (F-PAHs): Syntheses of difluorinated subfamily and their properties
Pinpoint-fluorinated polycyclic aromatic hydrocarbons (F-PAHs): Syntheses of difluorinated subfamily and their properties
复制标题
DOI：
10.1016/j.jfluchem.2017.09.002
复制
发表时间：
2017-11-01
影响因子：
1.9
通讯作者：
Ichikawa, Junji
中科院分区：
文献类型：
--
作者：
Fuchibe, Kohei;Shigeno, Kento;Ichikawa, Junji
通过Pd(II)催化的1，1，2-三氟烯和1，1-二氟-1-烯烃的Friedel-Craft型环化反应和In(III)催化的二(1，1-二氟烯)S串联环化反应，系统地合成了含3~5个苯环的二氟多环芳烃(PAHs)。(I)湾区氟原子的F-19核磁共振信号在Vic-二氟化多环芳烃中场下移了约8-14ppm，而对于非Vic-二氟化多环芳烃和单氟化多环芳烃则下移了约11-19ppm。(Ii)氟的引入增加了多环芳烃分子在有机溶剂中的溶解度，6，7-二氟环己烯(5.4wt%)和6-氟环芳烃(5.3wt%)在四氢呋喃中的高溶解度是最好的例证。(3)含氟多环芳烃的HOMO-LUMO能隙比相应的无氟多环芳烃的HOMO-LUMO能级小0.02-0.26 eV，HOMO能级降低0.10-0.22 eV，LUMO能级降低0.12-0.41 eV。
Difluorinated polycyclic aromatic hydrocarbons (PAHs) containing three to five benzene rings were systematically synthesized by the Pd(II)-catalyzed Friedel-Crafts-type cyclization of 1,1,2-trifluoro- and 1,1-difluoro-1-alkenes and the In(III)-catalyzed tandem cyclization of bis(1,1-difluoroallene)s. Using an array of the di-fluorinated PAHs that were obtained and previously reported monofluorinated PAHs, the physical properties of the pinpoint-fluorinated PAHs were investigated. (i) The F-19 NMR signals of the bay-region fluorine atoms were shifted downfield by ca. 8-14 ppm for vic-difluorinated PAHs and ca. 11-19 ppm for non-vic-difludrinated and monofluorinated PAHs. (ii) The introduction of fluorine into PAH molecules increased their solubilities in organic solvents, which was best exemplified by the high solubilities of 6,7-difluoropicene (5.4 wt%) and 6-fluoropicene (5.3 wt%) in THF. (iii) The HOMO-LUMO energy gaps of the pinpoint-fluorinated PAHs were smaller than that of the corresponding fluorine-free PAH (i.e., picene) by 0.02-0.26 eV, and the HOMO and LUMO energy levels were lowered by 0.10-0.22 eV and 0.12-0.41 eV, respectively.