154566-76-4

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• 154566-75-3 1,2-bis(5'-formyl-2'-methylthien-3'-yl)perfluorocyclopentene 

Relevant academic research and scientific papers

Light-Triggered Molecular Devices: Photochemical Switching of Optical and Electrochemical Properties in Molecular Wire Type Diarylethene Species

Organic photochromic systems represent a starting point for the elaboration of light-triggered molecular switching devices.The novel bispyridinium and bispyridine compounds 1(2+) and 6 were synthesized as their uncyclized isomers from 3,5-dibromo-2-methylthiophene in overall yields of 43 and 44percent, respectively.The diarylethene photochromes 2 and 10-13, substituted with electron donors and acceptors, were prepared from 5-methylthiophene-2-carboxaldehyde in 21-32percent overall yield.All of the compounds were found to exhibit pronounced photochromic properties.Irradiation with UV light resulted in essentially complete photocyclization of the open forms to the intensely coloured closed isomers which could, in turn, be reconverted back to the open state with visible light of λ > 600 nm.The absorption maxima of the discribed compounds in their closed forms are shifted far towards, and even into, the near-IR region.Whereas no thermochromic properties were observed for the open isomers, the rates of thermal decolouration of the cyclized forms was found to be highly dependent on the nature of the substituents on the thiophene rings.It was demonstrated that reversible photochemical interconversion between the two photochromic states could be used to effectively switch a number of physical properties.Thus, the molecules 1(2+) and 12 represent two kinds of redox switches, the former in reduction and the latter in oxidation, in which electron conduction is switched on in the closed state and off in the open state.Compound 12 may also be considered to be a photoswitchable analogue of tetrathiafulvalene type substances.On the other hand, compound 2 displays a marked increase in nonlinear optical activity on conversion from the open to the closed form.Such systems are prototypes of photoswitchable molecular wires where electron conduction and push-pull interaction can be reversibly modulated by an external stimulus, namely, irradiation by light. - Keywords: diarylethenes, molecular devices, nonlinear optics, photochromes, redox switches

Light-triggered Electrical and Optical Switching Devices

The functional photoswitchable systems 1-3 and 12-15 display pronounced photochromic properties; the bis-pyridinium derivative 1 represents a prototype of a switched molecular wire which may be converted from an open unconjugated form to a closed electron-conducting state.