Temperature Dependence of Excited Singlet S1-State Deactivation in Corrole Free Bases

Abstract

Исследована NH-таутомеризация в нижнем возбужденном синглетном S 1 состоянии свободного основания 5,10-мезитил-15-(2,6-дихлоропиримидинил)-коррола в интервале температур 278-318 K, и показано, что она является доминирующим каналом дезактивации энергии электронного возбуждения коротковолнового таутомера Т2. Установлено, что NH таутомеризация обуславливает существенные изменения квантовых выходов дезактивации энергии электронного возбуждения этого таутомера в зависимости от температуры. При ее увеличении до 318 K практически 90% энергии электронного возбуждения ансамбля молекул коррола в растворе после фототаутомеризации аккумулируется на синглетном S 1 состоянии длинноволнового таутомера Т1.

The role of solvents and concentrations in the properties of oxime bearing A2B corroles

“…Furthermore, it was possible to observe that, with all corroles, the T1 tautomer exhibits a wavelength absorption maximum at longer wavelengths, in agreement with the literature data. 15,22,43 In DMSO, the deprotonated form of the corrole, H 2 Corr À , is the existing form. The optimized structures show a planar conformation for the central tetrapyrrolic core, Fig.…”

Spectral Manifestations of Specific Solvation of 5,10,15,20-Tetrakis-(4-Sulfonatophenyl)-Porphyrin and its Doubly Protonated Form in Aqueous Solutions

“…The second group of thermochromic effects is based on conformational lability of tetrapyrroles and supramolecular systems based on them. If several stable conformers can form, their relative concentrations (i.e., the equilibrium between them) can be changed by varying the temperature or transferring the energy necessary to overcome the potential barrier separating the conformers [8][9][10][11][12][13][14]. The conformational transformations in such systems can be both the shift of one proton in the macrocycle core, i.e., NH tautomerism [8][9][10][11][12], and the migration of large molecular fragments relative to each other (limited to two macrocycles converting into a dimer [13,14]).…”

“…If several stable conformers can form, their relative concentrations (i.e., the equilibrium between them) can be changed by varying the temperature or transferring the energy necessary to overcome the potential barrier separating the conformers [8][9][10][11][12][13][14]. The conformational transformations in such systems can be both the shift of one proton in the macrocycle core, i.e., NH tautomerism [8][9][10][11][12], and the migration of large molecular fragments relative to each other (limited to two macrocycles converting into a dimer [13,14]). Thermochromic effects can be observed in the molecular ground and excited states or in only one of them depending on the height of the potential barrier [11,12].…”

“…The conformational transformations in such systems can be both the shift of one proton in the macrocycle core, i.e., NH tautomerism [8][9][10][11][12], and the migration of large molecular fragments relative to each other (limited to two macrocycles converting into a dimer [13,14]). Thermochromic effects can be observed in the molecular ground and excited states or in only one of them depending on the height of the potential barrier [11,12].…”