22559-70-2Relevant academic research and scientific papers
Photodissociation Electronic Spectra of Cold Protonated Quinoline and Isoquinoline in the Gas Phase
Féraud, Géraldine,Domenianni, Luis,Marceca, Ernesto,Dedonder-Lardeux, Claude,Jouvet, Christophe
, p. 2580 - 2587 (2017)
Photofragmentation electronic spectra of isolated single-isomeric N-protonated quinoline (quinolinium) and isoquinoline (isoquinolinium) ions have been measured at a temperature of ～40 K using a mass-selective, 10 cm-1 spectral resolution, photodissociation spectrometer. Additionally, ab initio adiabatic transition energies calculated using the RI-ADC(2) method have been employed to assist in the assignment of the spectra. Three electronic transitions having ππ? character were clearly evidenced for both protonated ions within the UV and deep-UV spectral ranges. The corresponding spectra at room temperature were previously reported by Hansen et al., together with TD-DFT calculations and a careful analysis of the possible fragmentation mechanisms. This information will be complemented in the present study by appending better resolved spectra, characteristic of cold ions, in which well-defined vibrational progressions associated with the S1 ← S0 and S3 ← S0 transitions exhibit clear 0-0 bands at hν0-0 = 27868 and 42230 cm-1, for protonated quinoline, and at hν0-0 = 28043 and 41988 cm-1, for protonated isoquinoline. Active vibrations in the spectra were assigned with the help of calculated normal modes, looking very similar to those of the structurally related protonated naphthalene. Finally, we have observed that the bandwidths associated with the deep-UV S3 ← S0 transition denote a lifetime for the S3 excited state in the subpicosecond time scale, in contrast with that of S1.
Acid/base-controllable fluorescent molecular switches based on cryptands and basic N-heteroaromatics
Cheng, Ming,Zhang, Jing,Ren, Xintong,Guo, Shuwen,Xiao, Tangxin,Hu, Xiao-Yu,Jiang, Juli,Wang, Leyong
supporting information, p. 11838 - 11841 (2017/11/03)
Two kinds of fluorescent BMP32C10-based cryptands 1 and 2 have been developed. Cryptand 1 contains a binaphthol group, while cryptand 2 bears a coumarin group in their third arms. Based on this design, novel self-assemblies constructed from cryptand 1 or 2 and basic N-heteroaromatic guests 3-6 were successfully obtained. Moreover, the threading/dethreading processes of the host-guest complexes could be well switched by the alternate addition of acid/base, and accompanied by concurrent changes in fluorescence.
