To overcome the poor solubility of the widely 8 used p-type dopant 2, 3,5,6-tetrafluoro-7,7,8,8-tetracyanoqui-9 nodimethane (F4TCNQ) 31,32 and 3,6-difluoro-2,5,7,7,8,8-75 In this paper, we first demonstrate a straightforward synthetic 88 route to soluble versions of F4TCNQ-type dopants by 89 substituting the cyano groups with either methyl or n-octyl f1 90 esters (Figure 1). A comprehensive study of the electro-91 chemical properties of these F4TCNQ analogues is performed 92 using cyclic voltammetry. With a combination of optical 93 absorption spectroscopy, photoluminescence spectroscopy, and 94 conductivity measurements, we not only demonstrate the p-95 type doping of P3HT using these new dopants, but also show 96 that comparable doping efficiency can be achieved even with 97 slightly reduced electron affinity. These novel molecular 98 dopants establish that the introduction of solubility control is 99 a successful strategy to tailor the properties of organic p-type 100 dopants. 101 ■ EXPERIMENTAL SECTION 102Materials. 1,4-Bis(chloromethyl)-2,3,5,6-tetrafluorobenzene was 103 purchased from Oakwood Products. Sodium hydride (60% dispersion 104 in mineral oil) was purchased from Alfa Aesar. Bromine, 105 perfluorobenzene, potassium carbonate, dimethyl carbonate, malono-106 nitrile, sodium acetate, sodium hydroxide, and phosphorus tribromide 107 were purchased from Sigma-Aldrich. Anhydrous dimethyl sulfoxide 108 (DMSO) and dimethylformamide (DMF) were purchased from Acros 109 Organics. Hydrochloric acid (37% aqueous), p-toluenesulfonic acid 110 monohydrate, ethanol, tetrahydrofuran (THF), dichloromethane 111 (DCM), ethyl acetate, toluene, and hexane were purchased from 112 Fisher Scientific. Acetic acid and sodium cyanide were purchased from 113 Fluka. Octanol was purchased from EM Science. Trifluoroacetic acid 114 (TFA) and acetic anhydride were purchased from EMD. P3HT 115 (Regioregular >98%, M n = 54−75 kDa, HOMO 5 eV and LUMO 3 116 eV) was purchased from Sigma-Aldrich. F4TCNQ (>98%) was 117 purchased from TCI. All chemicals were used as received unless 118 otherwise indicated. All solvents were dried over molecular sieves (3 119 Å) before use. 120Characterization.

Understanding the nature of dopant dynamics in the solid state is critical for improving the longevity and stability of organic electronic devices and for optimizing the dopinginduced solubility control (DISC) patterning method. In this work, we use quasi-elastic neutron scattering (QENS) and fluorescence quenching techniques to develop a comprehensive picture of both the microscopic and macroscopic dynamics of the soluble p-type molecular dopant tetrafluoromethyloxycarbonyltricyanoquinodimethane (F4MCTCNQ) in the conductive polymer poly(3-hexylthiophene-2,5-diyl) (P3HT). Specifically, fast dynamics (ps−ns) of the dopant, such as the methyl and the methoxycarbonyl group rotations, are observed in QENS experiments. From confocal fluorescence microscope experiments, longer-range/slower dopant diffusion (ms−days) iscaptured. However, in order to fit these data, it is necessary to incorporate a Langmuir isotherm equilibrium between the neutral and ionized dopant molecules. Ionized F4MCTCNQ is strongly favored by the equilibrium, but it diffuses 3 orders of magnitude slower than neutral species. Moreover, the macroscopic diffusion is found to depend mostly on the minority concentration of neutral dopant molecules in the film. Finally, the global diffusion coefficient of the monoester-substituted dopant F4MCTCNQ is shown to be more than 1 order of magnitude smaller than that of the widely used dopant F4TCNQ. 49 solution processes to achieve micrometer and submicrometer 50 resolution, respectively, in a method that is compatible with 51 roll-to-roll solution processing. 13,16 For DISC patterning, the 52 lateral diffusion of the dopant limits the ultimate resolution of 53 the pattern. Therefore, for both the stability of completed 54 organic devices and for fabrication of these devices using 55 solution compatible methods, understanding the dynamics of 56 the dopants is extremely important to further application 57 development. 58 The measurement of small molecular dopant diffusion is 59 particularly challenging because dopants are present in trace 60 quantities and composed of the same light elements (C, H, O, 61 N, S) as the host OSCs. Most of these studies so far have

This study investigated the effect of silane and surfactant treatments of graphene nanoplatelets (GnPs) on the mechanical and thermal properties of silicone rubber (SR) composites. GnPs were modified with aminopropyltriethoxysilane (APTES), vinyltrimethoxysilane (VTMS), and Triton X-100, and then the pristine GnPs and functionalized GnPs were individually incorporated into the SR. Compared with the pristine GnP/SR composite, the composites reinforced with modified GnP showed better tensile strength, elongation at break, and thermal conductivity properties due to better dispersion of modified GnPs and stronger interfacial interactions between the modified GnPs and matrix. The mechanical properties and thermal conductivity of the VTMS-GnP/SR composite were comparable to the properties of the Triton-GnP counterpart, but better than that of the APTES-GnP/SR composite. In addition, the VTMS-GnP/SR composite demonstrated the highest thermal stability and crystallization temperature among the four types of composites. The remarkable improvement of mechanical and thermal properties of the VTMS-GnP/SR composite was mainly due to the covalent linkage of VTMS-GnP with SR. The VTMS treatment was a more appropriate modification of GnP particles to improve the multifunctional properties of SR.

The intramolecular dehydrogenative amidation of aliphatic amides, directed by a bidentate ligand, was developed using a copper-catalyzed sp(3) C-H bond functionalization process. The reaction favors predominantly the C-H bonds of β-methyl groups over the unactivated methylene C-H bonds. Moreover, a preference for activating sp(3) C-H bonds of β-methyl groups, via a five-membered ring intermediate, over the aromatic sp(2) C-H bonds was also observed in the cyclometalation step. Additionally, sp(3) C-H bonds of unactivated secondary sp(3) C-H bonds could be functionalized by favoring the ring carbon atoms over the linear carbon atoms.

In combination with the advantages of organocatalysis, we have developed a highly enantioselective Friedel-Crafts aminoalkylation of indoles with imines generated in situ from trifluoroacetaldehyde methyl hemiacetal and aniline. Novel chiral trifluoromethyl-containing compounds were obtained in high yields with excellent enantioselectivities. This methodology was further extended to difluoroacetaldehyde methyl hemiacetal to demonstrate the broad scope of substrates.