Six polythiophenes (PThs) were synthesized via direct arylation polycondensation (DArP) with beta-fluorinated bithiophenes, that is, 4,4' -difluoro-2,2'-bithiophene (2FBT) and 3,3',4,4'-tetrafluoro-2,2...
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Six polythiophenes (PThs) were synthesized via direct arylation polycondensation (DArP) with beta-fluorinated bithiophenes, that is, 4,4' -difluoro-2,2'-bithiophene (2FBT) and 3,3',4,4'-tetrafluoro-2,2'-bithiophene (4FBT), as the C-H monomers and 5,5'-dibromo-2,2'-bithiophenes DCBT-2Br, DABT-2Br, and DTBT-2Br that carry alkoxycarbonyl, alkyl, and alkylthienyl side chains at 4,4'-positions, respectively, as the C-Br monomers. Both 2FBT and 4FBT are highly reactive for DArP, and high molecular weight PThs with unobservable chain defects were successfully synthesized from 2FBT/DCBT-2Br, 2FBT/DABT-2Br, 2FBT/DTBT-2Br, and 4FBT/DTBT-2Br. However, the DArP of 4FBT with DCBT-2Br and DABT-2Br produced PThs containing C-H/C-H homo-coupling defects along with relatively lower molecular weights. Detailed theoretical analysis suggests that the occurrence of C-Br reduction-provoked C-H/C-H homo-coupling for 4FBT/DCBT-2Br and 4FBT/DABT-2Br monomer pairs originated from the poor selectivity between the cis- and trans-forms of transition states in the concerted metalation-deprotonation (CMD) process is responsible for the formation of structural defects and depressed molecular weights. This research reveals that a C-H monomer with high reactivity and selectivity is not sufficient for the synthesis of well-defined conjugated polymers via DArP, and the structure of the C-Br monomer also has a significant impact on the results of DArP via influencing the catalytic cycles.
Higher education system is not only a complex nonlinear system, but also a complex adaptive system;Order and disorder is one of the most important concepts, the system works from disorderly to orderly is also an adapt...
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In this paper, we prove an optimal Heintze-Karcher-type inequality for anisotropic free boundary hypersurfaces in general convex domains. The equality is achieved for anisotropic free boundary Wulff shapes in a convex...
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Sustainable synthesis of polythiophenes (e.g.,P3HT) is highly desired for the development of low-cost organicsolar cells. Regulating the regioregularity of P3HT is a promisingway to boost its performance. Yet, few eco...
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Sustainable synthesis of polythiophenes (e.g.,P3HT) is highly desired for the development of low-cost organicsolar cells. Regulating the regioregularity of P3HT is a promisingway to boost its performance. Yet, few eco-friendly methods canprepare P3HT with tunable regioregularity. Herein, we put forwarda facile strategy tofinely modulate the regioregularity of P3HTfrom 90% to 98% by tuning the molar ratio of two ligands in directarylation polycondensation. Moreover, the ligand effect onregioregularity is well elucidated with DFT calculations, and theregioregularity effect of P3HT in non-fullerene solar cells isclarified for thefirst time. Our calorimetric, microscopic, and scattering results show that regioregularity strongly impacts thepolymer crystallinity and phase separation, and device performance of the blendfilms. The P3HT batch with a regioregularity of 95%yields an unprecedented power conversion efficiency of 10.82%. Importantly, this realizationfirmly provides optimism for cheapmaterials such as polythiophenes, which are made via eco-friendly polycondensation for the application of solar cells and beyond.
In this note, we study a Serrin-type partially overdetermined problem proposed by Guo-Xia (Calc. Var. Partial Differential Equations 58: no. 160, 2019. https://***/10.1007/s00526-019-1603-3), and prove a rigidity resu...
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In this paper, we first prove a rigidity result for a Serrin-type partially overdetermined problem in the half-space, which gives a characterization of capillary spherical caps by the overdetermined problem. In the se...
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In this paper, by isometrically embedding (Sn+1gSn+1) into Rn+2, and using nonlinear analysis on the codimension-2 graphs, we will show that the level-sets of the distance function from the boundary of any open set in...
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Direct arylation of 2,7-dibromofluorene with n-octyl, 6-diethoxylphosphorylhexyl, 6-(N,N-diethylamino)hexyl or 6-bromohexyl side chains and 1,2,4,5-tetrafluorobenzene (TFB) were conducted to investigate the effect of ...
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Direct arylation of 2,7-dibromofluorene with n-octyl, 6-diethoxylphosphorylhexyl, 6-(N,N-diethylamino)hexyl or 6-bromohexyl side chains and 1,2,4,5-tetrafluorobenzene (TFB) were conducted to investigate the effect of side chain functional groups on the coupling, and the resulting TFB-substituted fluorene derivatives were used as C-H monomers for the synthesis of water/alcohol soluble conjugated polymers (WSCPs) by direct arylation polycondensation (DArP). The direct arylation and DArP of the monomers carrying phosphonate and amino groups went on smoothly in typical DArP conditions, that is, Pd(OAc)(2)/(PBu2Me)-Bu-t-HBF4/base/DMAc and Pd-2(dba)(3)center dot CHCl3/P(o-MeOPh)(3)/pivalic acid/base/THF, and high molecular weight polymers with these groups were successfully synthesized. However, for fluorenemonomers with bromohexyl side chains, the target products could not be obtained from the above conditions but could be prepared in the absence of carboxylic acid additives in low polar solvents. With the above DArP-made polymers as cathode interfacial layers, high performance organic solar cells (OSCs) were successfully fabricated.
Herein, NiZn bimetallic oxides derived from calcination treatment of metal-organic frameworks (MOFs) were successfully loaded onto the carbon black waste as support obtained from the oil refinery. The resulting hybrid...
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Herein, NiZn bimetallic oxides derived from calcination treatment of metal-organic frameworks (MOFs) were successfully loaded onto the carbon black waste as support obtained from the oil refinery. The resulting hybrids could serve as environmentally friendly and cost-effective catalysts for the deoxygenation of biomass-derived fatty acids under an inert atmosphere. An online pyrolysis-gas chromatography/mass spectrometry (Py-GC/ MS) system was employed to evaluate their deoxygenation performance. The optimized catalysts demonstrated remarkably high stearic acid conversion of 99.6% and selectivity towards C8-C17 olefins of 57.2%. Furthermore, these catalysts with varying metal loadings also exhibited excellent efficiency in deoxygenation reactions of other types of fatty acids, such as myristic acid and palmitic acid, achieving conversion exceeding 85% and selectivities towards olefins of ca. 50%. When converting coconut oil, the supported NiZn bimetallic oxides showed excellent selectivity towards olefins (>60%). Furthermore, in-situ DRIFTS results suggest that fatty alcohols might be the key intermediates in the deoxidation reactions of fatty acid. This study not only demonstrates the great potential for obtaining valuable chemicals from biomass but also provides some insights into the fabrication of catalyst materials by using industrial solid waste.
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