/3-Carotene triplet state absorption in the near-IR range
نویسنده
چکیده
The/3-carotene absorption from the lowest triplet state was investigated over a wide spectral range. A new absorption transition in the nearIR region was found. The absorption band exhibited a 0--0 transition at about 8100 cm1 with a low intensity, lower by a factor of approximately 300 than the intensity of the known triplet-triplet absorption in the visible range. The vibronic structure of the absorption band was similar to that of the steady state/3-carotene absorption. The energy of the triplet state, resulting from this near-IR transition, was close to the fl-carotene S~ state energy. Correspondingly, the interconversion of the carotenoid should depend on the features of this triplet state. Moreover, this relatively low-lying triplet state could also take part in the quenching of molecular triplet states by carotenoids.
منابع مشابه
Heteroleptic cationic iridium(III) complexes bearing naphthalimidyl substituents: synthesis, photophysics and reverse saturable absorption.
Three heteroleptic cationic iridium(iii) complexes containing a cyclometalating 2-[3-(7-naphthalimidylfluoren-2'-yl)phenyl]pyridine ligand and different diimine (N^N) ligands (N^N = 2,2'-bipyridine (bpy, ), 1,10-phenanthroline (phen, ), and 5,5'-bis[7-(benzothiazol-2'-yl)fluoren-2'-yl]-2,2'-bipyridine (BTF-bpy, )) were synthesized and characterized. The photophysics of these complexes was syste...
متن کاملTriplet state characteristics of IR laser dyes: A pulse radiolysis study
The IR-dyes, having the absorption maximum in the range of 600 nm to 1100 nm, are expected to have very low triplet e nergy level. The triplet-triplet (T-T) absorption spectra and decay characteris tics have becn invcstigated for four IR laser dyes, namely, IR-140, IR-144, Q-Switch I and Q-Switch 5. Triplet state of these IR dyes are generated by electron pulse radiolysis in benzene-benzonitril...
متن کاملAccessing the long-lived near-IR-emissive triplet excited state in naphthalenediimide with light-harvesting diimine platinum(II) bisacetylide complex and its application for upconversion.
Room temperature near-IR phosphorescence of naphthalenediimide (NDI) was observed with N^N Pt(II) bisacetylide complex (Pt-NDI) in which the NDI was connected to Pt(II) center via acetylide. Pt-NDI shows intense absorption of visible light and long-lived NDI-localized excited state ((3)IL) (τ(T) = 22.3 μs). Pt-NDI was used as a triplet sensitizer for upconversion.
متن کاملRed-light-absorbing diimine Pt(II) bisacetylide complexes showing near-IR phosphorescence and long-lived 3IL excited state of Bodipy for application in triplet-triplet annihilation upconversion.
Bodipy is used for the preparation of Pt(II) bisacetylide complexes which show strong absorption of visible light and long-lived triplet state. Room temperature (RT) near-IR phosphorescence of Bodipy was observed. The π-conjugation framework of visible light-harvesting Bodipy ligand was connected to the Pt(II) center by the C≡C bond. The complexes were used as triplet photosensitizers for tripl...
متن کاملObservation of the long-lived triplet excited state of perylenebisimide (PBI) in C^N cyclometalated Ir(III) complexes and application in photocatalytic oxidation.
Perylenebisimide (PBI) was used to prepare C^N cyclometalated Ir(III) complexes that show strong absorption of visible light and it is the first time the long-lived triplet excited state of PBI chromophore was observed in a transition metal complex (τT = 22.3 μs). Previously, the lifetime of the triplet state of PBI in transition metal complexes was usually shorter than 1.0 μs. Long-lived tripl...
متن کامل