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Femtosecond Spectroscopy and Dynamics of the Azulenylosquaric Dye, a Near‐infrared Nonfluorogenic Quencher
Author(s) -
Cheng YiMing,
Wu IChe,
Lai ChinHung,
Pu ShihChieh,
Chou PiTai,
Wei ChingYen,
Yu ChaoYing,
Lin YiHsin,
Ting Ching
Publication year - 2006
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200600170
Subject(s) - chemistry , ultrafast laser spectroscopy , femtosecond , photon upconversion , photochemistry , absorption (acoustics) , spectroscopy , fluorescence , absorption spectroscopy , internal conversion , time resolved spectroscopy , molar absorptivity , kinetics , analytical chemistry (journal) , spectral line , optics , ion , laser , organic chemistry , physics , quantum mechanics , astronomy
An azulenylosquaric dye ( ASQ ) has been synthesized to investigate its associated photophysical properties. ASQ is essentially nonluminescent (Φ f < 3 × 10 −;6 ) in any solvent despite its very high absorption extinction coefficient (760 nm, ε ˜ 8.2 × 10 4 M −;1 cm −;1 in methanol). Femtosecond fluorescence upconversion, anisotropy kinetics and transient absorption experiments, in combination with the theoretical time‐dependent DFT approach, leads us to conclude that the 760 nm absorption is ascribed to the fully allowed S 0 → S n (n 2) transition. The observed < 130 fs decay component is attributed to the S n → S 1 internal conversion, while the S 1 → S 0 , with a slower radiative decay time (> 233 ns) undergoes a dominant radiationless deactivation process (710 70 fs) possibly governed by strong interaction between S 1 and S 0 potential energy surfaces.