265653-38-1Relevant academic research and scientific papers
Dual Emission of meso-Phenyleneethynylene–BODIPY Oligomers: Synthesis, Photophysics, and Theoretical Optoelectronic Study
Flores, J. Reyes,Castruita-De León, Griselda,Turlakov, Gleb,Arias, Eduardo,Moggio, Ivana,Montemayor, Sagrario M.,Torres, Román,Ledezma, Raquel,Ziolo, Ronald F.,González-Torres, Julio
, p. 2493 - 2505 (2020/12/23)
Two series of 2,5-di(butoxy)phenyleneethynylenes, one halogenated (nPEC4-X; n=2, 3, or 4) and the other boron-dipyrromethene (BODIPY) terminated (nPEC4-By; n=3, 4, or 5; By=BODIPY), were synthesized monodirectionally by the step-by-step approach and the molecular structure was corroborated by NMR spectroscopy (1H, 13C-DEPTQ-135, COSY, HSQC, HMBC, 11B, 19F) and MALDI-TOF mass spectrometry. The multiplicity and J-coupling constants of 1H, 11B, and 19F/11B NMR signals revealed, in the nPEC4-By series, that the phenyl in the meso position of BODIPY becomes electronically part of the conjugation of the phenyleneethynylene chain, whereas BODIPY is electronically isolated. The photophysical, electrochemical, and theoretical studies confirm this finding because the properties of nPEC4-By are comparable to those of the nPEC4-X oligomers and BODIPY, indicating negligible electron communication between BODIPY and the nPEC4 moieties. Nevertheless, energy transfer (ET) from nPEC4 to BODIPY was rationalized by spectroscopy and theoretical calculations. Its yield decreases with the nPEC4 conjugation length, according to the increase in distance between the two chromophores, resulting in dual emission for the longest oligomer in which ET is quenched.
Alkyloxy modified pyrene fluorophores with tunable photophysical and crystalline properties
Kapf, Andreas,Eslahi, Hassan,Blanke, Meik,Saccone, Marco,Giese, Michael,Albrecht, Marcel
, p. 6361 - 6371 (2019/04/25)
Novel alkyloxy modified 2,7-di-tert-butyl-4,5,9,10-tetra(arylethynyl)pyrenes were prepared through a straightforward Sonogashira coupling approach. Optical properties such as quantum yields and absorption/emission spectra of the fluorophores were investigated by UV/Vis and fluorescence measurements. Aggregation induced excimer formation of the chromophores in polar solvents and in the solid state was proved by the presence of a characteristic bathochromically shifted emission band and a decrease of the emission capability. These results strongly indicate the unexpected observation that the excimer formation of adjacent pyrene rings is not prevented by the introduction of bulky tert-butyl substituents. Single-crystal X-ray and computational analyses reveal the co-planar alignment of adjacent molecules and the presence of π-π-stacking in the molecular packing of the pyrene polyaromatics. Furthermore, fluorescence, DSC and POM measurements indicate that the aggregation behaviour, the thermal characteristics and the crystalline properties are significantly influenced by changing structural features of the attached functional groups at the periphery of the pyrene core.
Reactivity switch enabled by counterion: Highly chemoselective dimerization and hydration of terminal alkynes
Xu, Caixia,Du, Weiyuan,Zeng, Yi,Dai, Bin,Guo, Hao
supporting information, p. 948 - 951 (2014/03/21)
A counterion-controlled reactivity tuning in Pd-catalyzed highly chemoselective and regioselective dimerization and hydration of terminal alkynes is reported. The use of acetate as counterion favors the formation of an alkenyl alkynyl palladium intermediate which forms hitherto less reported 1,3-diaryl-substituted conjugated enynes after reductive elimination. Using chloride, which is a better leaving group, leads to anion exchange on the alkenylpalladium intermediate with hydroxide which after reductive elimination and tautomerization delivered the hydration products.
Synthesis of diphenyl-diacetylene-based nematic liquid crystals and their high birefringence properties
Arakawa, Yuki,Nakajima, Shunpei,Ishige, Ryohei,Uchimura, Makoto,Kang, Sungmin,Konishi, Gen-Ichi,Watanabe, Junji
supporting information; experimental part, p. 8394 - 8398 (2012/07/28)
We synthesized two series of diphenyl-diacetylene (DPDA)-based materials with alkoxy and alkyl tails of length m (DPDA-OCm and DPDA-Cm, respectively), and measured their nematic-phase birefringence (Δn) as a function of wavelength and temperature. We found that Δn decreases with an increase in m, possibly by a dilution effect of the low-Δn alkyl tail. Further, of the two series, Δn was found to be relatively higher in the DPDA-OCm materials, with the highest value of 0.4 obtained for DPDA-OC1 at 550 nm at 10 °C below the isotropic-to-nematic transition temperature. Further, we observed the temperature dependence for Δn, which is proportional to the order parameter (s). From extrapolation to s = 1 (the perfect orientation state), it is speculated that the DPDA-O moiety has the potential to afford a very large Δn of 0.9. The Royal Society of Chemistry 2012.
