568592-12-1Relevant academic research and scientific papers
Dopant-Free Hole-Transporting Polycarbazoles with Tailored Backbones for Efficient Inverted Perovskite Solar Cells
Xie, Yuanyuan,Wang, Xuxian,Chen, Qing,Liu, Sizhou,Yun, Yikai,Liu, You,Chen, Cheng,Wang, Jungan,Cao, Yezhou,Wang, Fangfang,Qin, Tianshi,Huang, Wei
, (2019/07/03)
Three conjugated polymers based on different linkage sites of carbazole repeat units, 3,6-PCzTPA, 2,7-PCzTPA, and 3,6-2,7-PCzTPA, were obtained through judicious molecular engineering. We observed that structure differences between 2,7- and 3,6-carbazole linkage sites could significantly influence intra- and intermolecular architectures and electronic states of materials. Herein, 3,6-PCzTPA and 3,6-2,7-PCzTPA with 3,6-carbazole units exhibited higher hole mobilities owing to the formation of radical cations, compared to 2,7-PCzTPA with 2,7-carbazole units. As a result, by using 3,6-2,7-PCzTPA as the hole-transporting material, perovskite solar cells with the p-i-n structure demonstrated the highest power conversion efficiency up to 18.4%. The outstanding device performance originated from compositive values of open-circuit voltage and fill factor, which were attributed to the suitable energy level as well as a high hole mobility of 3,6-2,7-PCzTPA. Moreover, its straightforward synthesis strategy, fine film-formation ability, and nondopant requirement indicated 3,6-2,7-PCzTPA as an ideal hole-transporting material for perovskite solar cells.
Site-Selective N-Arylation of Carbazoles with Halogenated Fluorobenzenes
Wang, Lei,Ji, Enhui,Liu, Ning,Dai, Bin
, p. 737 - 750 (2016/02/27)
A method for the highly site-selective C-N bond-formation reaction of halogenated fluorobenzenes with carbazoles is described. The selectivity of iodine and fluorine atoms on the aromatic ring of fluorinated iodobenzenes was initially determined with a copper-N,N-diisopropylethylamine catalytic system. By changing the position of the iodine atom on the aromatic ring from the 3- or 4-position to the 2-position, the preferred coupling site was switched from the iodine atom to the fluorine atom. Steric hindrance of the fluorinated iodobenzenes is responsible for the selectivity switch. After elucidating the reaction mechanisms of these reaction processes, a metal-free method for the highly site-selective C-N bond-formation reaction of halogenated fluorobenzenes with carbazoles was revealed through C-F bond activation. The metal-free system is able to handle a range of halogenated groups. Thus, a broad range of chlorinated, brominated, and iodinated N-arylated carbazoles were generated, which are widely useful in organic chemistry.
One-pot two-step synthesis of: N -arylcarbazole-based skeleton
Tao, Sheng,Liu, Ning,Dai, Bin
, p. 43250 - 43260 (2016/05/24)
A highly site-selective, one-pot, sequential C-N and C-C bond forming process was developed, affording a carbazole-based skeleton that contains biphenyl and diarylacetylene cores. The success of this process is attributed to the use of fluorinated iodoarenes as the starting material, the fluorine group of which preferentially reacts with carbazole. The subsequent coupling of the intermediate iodinated N-arylcarbazole with arylboronic acid or arylacetylene produced the desired products. The intermediate underwent a Pd-catalyzed Ullmann coupling with excess fluorinated iodoarenes in the absence of arylboronic acid or arylacetylene, resulting in Ullmann coupling products in a one-pot process.
Copper/β-diketone-catalysed N-arylation of carbazoles
Chen, Fei,Liu, Ning,Ji, Enhui,Dai, Bin
, p. 51512 - 51523 (2015/06/25)
A copper-catalysed C-N bond-forming reaction of carbazoles with aryl iodides is described. Several commercially available ligands such as β-diketone and diamine, are tested in the N-arylation of carbazoles. The catalytic system generated in situ from an inexpensive copper salt, simple β-diketone and inorganic base efficiently N-arylated the carbazoles. A wide range of aryl iodides and carbazoles can be coupled to generate N-arylcarbazoles in the presence of various functional groups. However, the sterically hindered effect of aryl iodides is evident in this catalytic system. The selectivity of two iodine atoms on the aromatic ring of diiodobenzene is evaluated in the developed catalytic system. Results showed that the selectivity of diiodobenzene can be tuned by the reaction temperature.
En route to surface-bound electric field-driven molecular motors
Jian, Huahua,Tour, James M.
, p. 5091 - 5103 (2007/10/03)
Four caltrop-shaped molecules that might be useful as surface-bound electric field-driven molecular motors have been synthesized. The caltrops are comprised of a pair of electron donor-acceptor arms and a tripod base. The molecular arms are based on a carbazole or oligo(phenylene ethynylene) core with a strong net dipole. The tripod base uses a silicon atom as its core. The legs of the tripod bear sulfur-tipped bonding units, as acetyl-protected benzylic thiols, for bonding to a gold surface. The geometry of the tripod base allows the caltrop to project upward from a metallic surface after self-assembly. Ellipsometric studies show that self-assembled monolayers of the caltrops are formed on Au surfaces with molecular thicknesses consistent with the desired upright-shaft arrangement. As a result, the zwitterionic molecular arms might be controllable when electric fields are applied around the caltrops, thereby constituting field-driven motors.
