63619-60-3Relevant academic research and scientific papers
End-Functionalization of Diarylethene for Opto-Electronic Switching with High Fatigue Resistance
Hassan, Syed Zahid,Yu, Seong Hoon,So, Chan,Moon, Dohyun,Chung, Dae Sung
, p. 403 - 412 (2021/01/13)
A molecular and synthetic approach to strengthen the switching performance of diarylethene (DAE)-based organic transistors is proposed. By tuning the length of alkyl side chains of the biphenyl unit attached to 1,2-bis(5-biphenyl-2-methylthien-3-yl)perfluorocyclopentene (DAE), we show that the molecular environment for reversible photoisomerization of DAEs can be optimized. Four different DAEs are synthesized with different alkyl chains (DAE_C0, DAE_C1, DAE_C6, and DAE_C10), and ITIC is chosen to construct a semiconductor matrix to maximize the quantum yield of photoconversion considering the complementary absorption range of both materials. From photophysical, structural, and morphological analyses, the longer alkyl chains inhibit intermolecular aggregation between DAEs and allow more hydrophobic surface properties of DAEs, thus improving molecular miscibility with ITIC. The improved molecular compatibility of DAEs with ITIC makes the overall bulk heterojunction film amorphous, allowing more free volume for reversible photoisomerization. Consequently, DAE_C6 exhibits the maximum quantum yield for both photocyclization and photocycloreversion, enabling high light-controlled on/off ratios in photoswitchable transistors. Furthermore, the exceptionally high DAE_C6 quantum yield enables robust fatigue resistance under repeated photoswitching with only a 30% decrease in the on/off ratio after 100 cycles. Overall, this work shows that not only the energy level but also the molecular compatibility can endow significant switching performances for molecular switches.
Enantiotropic nematics from cross-like 1,2,4,5-tetrakis(4'-alkyl-4- ethynylbiphenyl)benzenes and their biaxiality studies
Chen, Hsiu-Hui,Lin, Hsing-An,Lai, Yin-Hui,Lin, Shu-Yu,Chiang, Chien-Hung,Hsu, Hsiu-Fu,Shih, Tzenge-Lien,Lee, Jey-Jau,Lai, Chien-Chen,Kuo, Ting-Shen
scheme or table, p. 9543 - 9551 (2012/09/07)
The theoretically predicted optimum length/breadth/width ratio for maximizing shape biaxiality was investigated experimentally by the facile and successful synthesis of cross-shaped compound 3, which showed enantiomeric nematic phase behavior. This cross-like core structure could alternatively be viewed as two fused V-shaped mesogens, which have recently immerged as a new direction in biaxial nematic research, at the bending tips that can act as a new structure for biaxial investigations. Whilst the thermal analysis data of compound 3 did not meet the expected theoretical values for biaxial nematics, surface-induced biaxiality was evidenced by optical studies. Cluster-size analysis within the nematic phase of compound 3 revealed the formation of meta-cybotactic nematics, which approached the cluster sizes of cybotactic nematics. The split small-angle 2D X-ray diffraction patterns of magnetic-field-aligned samples indicated that the nematic phase was composed of small smectic C-like clusters with the tilting of molecules within the clusters. The wide-temperature-range enantiomeric nematic phase of cross-like compound 3 enabled the molecular skeleton to serve as an alternative skeleton to bent-rod mesogens, which exhibited nematic phases with the potential competition of transitions to higher-order liquid-crystalline phases and crystallization, for future biaxial investigations. Take up your cross: An enantiotropic nematic phase with a wide temperature range has been achieved by using cross-like mesogens. Biaxiality investigations by using conoscopic and 2D XRD studies imply the formation of small smectic C-like meta-cybotactic clusters in the nematic arrangement. Copyright
Synthesis of thiophene/phenylene co-oligomers. V [1]. Functionalization at molecular terminals toward optoelectronic device applications
Katagiri, Toshifumi,Ota, Satoshi,Ohira, Takayuki,Yamao, Takeshi,Hotta, Shu
, p. 853 - 862 (2008/04/12)
(Chemical Equation Presented) We report the synthesis of various thiophene/phenylene co-oligomers with a total number of thiophene and benzene (phenylene) rings of 5 and 6 with various terminal groups. Those terminal groups have been chosen from among alkyl groups, methoxy groups, trifluoromethyl groups, and cyano groups. The molecular backbone of these compounds comprises phenyl- or biphenylyl-capped thiophene (or oligothiophene) or an alternating co-oligomer. The synthesis is based on either the Suzuki coupling reaction or the Negishi coupling reaction. These reaction schemes enabled us to obtain the target compounds in high quality. In particular, the latter coupling method turned out to produce the compounds at a high yield. The terminal groups are expected to produce various functionalities based upon their electron donating character (alkyl groups and methoxy groups) or electron withdrawing character (trifluoromethyl groups and cyano groups). Additionally some of these groups bring about enhanced solubility. This will lead to the production of a diversity of modified compounds of thiophene/phenylene co-oligomers. To give an example that demonstrates usefulness of the target compounds, we present optoelectronic data that are associated with their device applications.
Synthesis of Mesogenic Compounds, Catalyzed by Metal Complexes. I. Monoalkylation and Monoarylation of 1,4-Dibromobenzene in the Synthesis of 4-n-Alkyl- and 4-n-Alkoxy-4'-Cyanobiphenyls Catalyzed by Palladium
Bumagin, N. A.,Luzikova, E. V.,Beletskaya, I. P.
, p. 1480 - 1486 (2007/10/03)
New methods of synthesis of mesomorphic 4-n-alkyl- and 4-n-alkoxy-4'-cyanobiphenyls are developed, based on the palladium catalyzed highly selective reactions of 1,4-dibromobenzene with alkyl and aryl Grignard reagents.
