merocyanine-dye and acetonitrile

merocyanine-dye has been researched along with acetonitrile* in 2 studies

Other Studies

2 other study(ies) available for merocyanine-dye and acetonitrile

Article	Year
Direct photoreduction and ketone-sensitized reduction of nitrospirobenzopyranindolines by aliphatic amines. The journal of physical chemistry. A, 2011, Jul-28, Volume: 115, Issue:29 The photoreduction of 6-nitrospiro[2H-1-benzopyran-2,2'-indoline] (N1) and two derivatives (N2 and N3) by diethylamine or triethylamine (TEA) in solution was studied by pulsed and steady-state photolysis. The quantum yield of coloration of the ring-closed Sp form, due to photoinduced ring opening, decreases in acetonitrile with increasing the TEA concentration. The main reason is reaction of TEA with the triplet-excited open merocyanine form. Quenching of this triplet state by amines is rather inefficient for N1-N3; the rate constant for triplet quenching by TEA is k(6) = (2-3) × 10(6) M(-1) s(-1). The secondary transient with an absorption maximum at 420 nm is ascribed to the radical anion. This and the corresponding α-aminoethyl radical subsequently undergo slow termination reactions, yielding a relatively stable product with a maximum at 420-450 nm, which is attributed to a ring-opened dihydromerocyanine (MH(-)). The mechanisms of the two subsequent reduction reactions are discussed. Using acetone as sensitizer the same dihydroproduct was obtained with the Sp form as acceptor, indicating a reaction sequence from photogenerated radicals via a ring-opened radical to MH(-)/MH(2). The effect of TEA concentration on the direct and ketone-sensitized reduction mechanisms was analyzed. Photoreduction by amines, due to competing triplet quenching, is strongly decreased on admission of oxygen. Topics: Acetonitriles; Benzopyrans; Chemistry, Physical; Diethylamines; Ethylamines; Indoles; Ketones; Kinetics; Light; Oxidation-Reduction; Oxygen; Photolysis; Pyrans; Solutions; Solvents; Spectrum Analysis; Spiro Compounds	2011
Solvent tuning of a conical intersection: direct experimental verification of a theoretical prediction. The journal of physical chemistry. A, 2011, Oct-13, Volume: 115, Issue:40 We report an ultrafast study of a merocyanine molecule, whose fluorescence lifetime was tuned by changing the solvent's polarity. A recent theoretical prediction that the fluorescence lifetime is considerably shortened upon lowering the polarity of the solvent, due to tuning of the conical intersection properties, is fully confirmed (Xu et al. J. Phys. Chem. A 2009, 113, 9779-9791). This constitutes a direct measurement of a previously predicted tunable property of a conical intersection. Topics: Acetonitriles; Benzopyrans; Indoles; Molecular Structure; Quantum Theory; Solvents; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Toluene	2011

Article

Year

Direct photoreduction and ketone-sensitized reduction of nitrospirobenzopyranindolines by aliphatic amines.

The journal of physical chemistry. A, 2011, Jul-28, Volume: 115, Issue:29

The photoreduction of 6-nitrospiro[2H-1-benzopyran-2,2'-indoline] (N1) and two derivatives (N2 and N3) by diethylamine or triethylamine (TEA) in solution was studied by pulsed and steady-state photolysis. The quantum yield of coloration of the ring-closed Sp form, due to photoinduced ring opening, decreases in acetonitrile with increasing the TEA concentration. The main reason is reaction of TEA with the triplet-excited open merocyanine form. Quenching of this triplet state by amines is rather inefficient for N1-N3; the rate constant for triplet quenching by TEA is k(6) = (2-3) × 10(6) M(-1) s(-1). The secondary transient with an absorption maximum at 420 nm is ascribed to the radical anion. This and the corresponding α-aminoethyl radical subsequently undergo slow termination reactions, yielding a relatively stable product with a maximum at 420-450 nm, which is attributed to a ring-opened dihydromerocyanine (MH(-)). The mechanisms of the two subsequent reduction reactions are discussed. Using acetone as sensitizer the same dihydroproduct was obtained with the Sp form as acceptor, indicating a reaction sequence from photogenerated radicals via a ring-opened radical to MH(-)/MH(2). The effect of TEA concentration on the direct and ketone-sensitized reduction mechanisms was analyzed. Photoreduction by amines, due to competing triplet quenching, is strongly decreased on admission of oxygen.

Topics: Acetonitriles; Benzopyrans; Chemistry, Physical; Diethylamines; Ethylamines; Indoles; Ketones; Kinetics; Light; Oxidation-Reduction; Oxygen; Photolysis; Pyrans; Solutions; Solvents; Spectrum Analysis; Spiro Compounds

2011

Solvent tuning of a conical intersection: direct experimental verification of a theoretical prediction.

The journal of physical chemistry. A, 2011, Oct-13, Volume: 115, Issue:40

We report an ultrafast study of a merocyanine molecule, whose fluorescence lifetime was tuned by changing the solvent's polarity. A recent theoretical prediction that the fluorescence lifetime is considerably shortened upon lowering the polarity of the solvent, due to tuning of the conical intersection properties, is fully confirmed (Xu et al. J. Phys. Chem. A 2009, 113, 9779-9791). This constitutes a direct measurement of a previously predicted tunable property of a conical intersection.

Topics: Acetonitriles; Benzopyrans; Indoles; Molecular Structure; Quantum Theory; Solvents; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Toluene

2011