Fluorescence quenching and laser photolysis of dipyrrolylbenzenes in the presence of chloromethanes

Deprotonation of short-living radical cations of pyrrolylbenzenes*

“…Synthesis of compound 1 by the Trofimov reaction was described in [4]. MeCN and CHCl 3 from Merck Uvasol (99.9%) were used without further purification.…”

“…We discovered previously [4] that on stationary photolysis of dipyrrolylbenzenes in the presence of chloromethanes colored products of an oligomeric nature are observed with λ max ~ 610 nm (subsequently product P600), genetically linked with radical cations (Scheme 1, 1.7). In [4] the nature of the oligomers was not specially studied.…”

“…In [4] the nature of the oligomers was not specially studied. We note that the dication of 2,2'5'2":5",2"'-quaterpyrrole has a very similar shaped absorption band in the visible region (λ max = 680 nm).…”

The nature of transitions in electronic absorption spectra of radical cations of dipyrroles with phenylene bridging groups

“…Earlier, 4 we have reported preliminary data on the band positions in the electronic absorption spectra of the radical cations of 1,4 bis(2 pyrrolyl)benzene (1), 1 (2 pyrrolyl) 4 (1 vinyl 2 pyrrolyl)benzene (2), and 1,4 bis[2 (1 vinyl 2 pyrrolyl)]benzene (3) obtained by the NLP method. In the present work, both experimental studies and quantum chemical calculations of the electronic absorption spectra of the radical cations of compounds 1-3 and of the more recently synthesized 4 (3 methyl 2 pyrrolyl) 1 (2 pyr rolyl)benzene (4), 1 (2 pyrrolyl) 4 (1 vinyl 3 methyl 2 pyrrolyl)benzene (5), and 4 (1 vinyl 3 methyl 2 pyrrol yl) 1 (1 vinyl 2 pyrrolyl)benzene (6) were performed to analyze in more detail the nature of electronic transitions in the spectra of radical cations.…”

“…[1][2][3][4] The spectral lu minescent and photophysical properties of this type of comonomers show high sensitivity to the nature and posi tion of substituents in the pyrrole and benzene rings and the possibility of fine adjustment of their optical pro perties. 3,5,6 However, the electronic and molecular struc tures of DPB radical cations, which should to a great extent determine the mechanism of polymerization, as well as the injection and charge transport properties, are poorly studied.…”