Indexed by:
Abstract:
Three azobenzenes 4 similar to 6 conjugated with 4,4'-dimethoxy-triphenylamine redox center have been synthesized by palladium-catalyzed Sonogashira coupling reactions in moderate yield after column chromatographic purification. They are all stable when exposed in air and moisture in both the solid and solution state. The H-1 NMR spectra of 4 similar to 6 showned that the azobenzene groups are in the trans configuration. The UV/Vis spectra of the target molecule were studied. The UV/Vis absorption bands of 4 similar to 6 are less clearly separated, which is similar to those for aminoazobenzen or pseudostilbene. The absorption bands at the pi ->pi* band of 4 and 6 are redshifted, due to the strong electronic interaction between the azobenzene unit and the para-triphenylamine unit, which results in the formation of a longer conjugation system than the corresponding meta isomers. Electrochemical and spectroelectrochemical studies indicate excellent redox reversibility of these compounds. Significant spectra change upon the process of redox makes these compounds have potential applications of electrochemical switching. Among the derivatives, compound 4 exhibits the highest cis form (45%) in the photostationary state (PSS) upon light irradiation at 435 nm. The photoisomerization studies indicate that the photochemistry properties is strongly influenced by the substituted position of the triphenylamine moiety. Photoisomerization studies showed that these compounds have fast photoisomerization rate due to the higher photoisomerization quantum yield, which is an order of magnitude larger than that of ferrocenyl (ethynyl) azobenzenes. Both compounds 4 and 6 exhibit excellent fatigue resistance and reversibility under several repeated reversible isomerization cycles. The cis-to-trans photoisomerization of 4 can be not only achieved by irradiation at UV lignt, but also realized by a more efficient way of change the state of redox center. Our study will provide a good basis for research in design new type of multiple-response molecular switches.
Keyword:
Reprint 's Address:
Email:
Source :
CHINESE JOURNAL OF ORGANIC CHEMISTRY
ISSN: 0253-2786
CN: 31-1321/O6
Year: 2019
Issue: 7
Volume: 39
Page: 2009-2017
1 . 3 4 4
JCR@2019
1 . 8 0 0
JCR@2023
ESI HC Threshold:184
JCR Journal Grade:3
CAS Journal Grade:3
Cited Count:
WoS CC Cited Count: 3
SCOPUS Cited Count: 3
ESI Highly Cited Papers on the List: 0 Unfold All
WanFang Cited Count:
Chinese Cited Count:
30 Days PV: 0
Affiliated Colleges: