Nature and characterization of the singlet and triplet excited states of the dibenzylideneacetone and di-3-(N-ethylcarbazoylidene)acetone bridging ligands

1992 ◽  
Vol 70 (11) ◽  
pp. 2777-2784 ◽  
Author(s):  
Pierre D. Harvey ◽  
Benoit Daoust
Keyword(s):  
Excited States ◽  
Model Compound ◽  
Energy Transition ◽  
Quantum Yields ◽  
Bridging Ligands ◽  
Fluorescence Quantum Yields ◽  
A Charge ◽  
Triplet Excited States ◽  
First Time

The lowest energy singlet state in di-3-(N-ethylcarbazoylidene)acetone (dNECa), a luminescent model compound at room temperature for dibenzylideneacetone (dba), has been assigned to a charge transfer (CT) state using the medium polarity effect on λmax(F) and the fluorescence polarized spectra of dNECa at 77 K. The dNECa fluorescence quantum yields [Formula: see text] and lifetimes (τF) are solvent sensitive where both [Formula: see text] and τF tend to increase with polarity. The very weak and moderately structured phosphorences have been located for the first time for both dba and dNECa in the 550–800 nm range and are also assigned to a CT state. In this case the CT interactions are less pronounced than λ(0–0)P and τP are much less solvent sensitive. Finally, EHMO type calculations confirm that the CT transition is the lowest energy transition in dba and di-3-(N-methylindoylidene)acetone (a model compound for dNECa), but also suggest that the nπ* state must lie near the CT state in dba.

Photophysical and photochemical properties of fluoroether-substituted zinc(II) and titanium(IV) phthalocyanines

2018 ◽  
Vol 22 (01n03) ◽  
pp. 46-55 ◽  
Author(s):  
İlke Gürol ◽  
Gülay Gümüş ◽  
Deniz Kutlu Tarakci ◽  
Ömer Güngör ◽  
Mahmut Durmuş ◽  
...  
Keyword(s):  
Quantum Yields ◽  
Central Metal Atom ◽  
Spectroscopic Techniques ◽  
Central Metal ◽  
Oxygen Generation ◽  
Fluorescence Quantum Yields ◽  
H Nmr ◽  
Photochemical Properties ◽  
First Time

The synthesis and characterization of novel zinc(II) (1a–4a) and oxo-titanium(IV) (1b–4b) phthalocyanine derivatives bearing 1H,1H-nona?uoro-3,6-dioxaheptan-1-ol groups are described for the first time. These phthalocyanines (1a–4a and 1b–4b) were characterized by elemental analysis and different spectroscopic techniques such as UV-vis, [Formula: see text]H NMR, FTIR and mass. Furthermore, the photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation and photodegradation) properties of these phthalocyanines were investigated in tetrahydrofuran (THF) solution. The influence of the number of the substituted groups (tetra or octa), position of the substituents (peripheral or non-peripheral) and central metal atom (zinc or titanium) on the photophysical and photochemical properties of these phthalocyanines were evaluated.

scholarly journals Abnormally aggregation-induced emissions observed from hydrogen- and silyl-substituted siloles

2020 ◽  
Vol 43 (1) ◽  
pp. 125-131
Author(s):  
Zhengang Han ◽  
Kefeng Xie
Keyword(s):  
Hydrogen Atom ◽  
Theoretical Calculations ◽  
Quantum Yields ◽  
Aggregation Induced Emission ◽  
Fluorescence Quantum Yields ◽  
High Fluorescence ◽  
First Time

AbstractSilacyclopentadienes (siloles) are currently of great interest because of their intriguing aggregation-induced emission (AIE) characteristics. In this work, abnormally AIE phenomena were observed from silyl- and hydrogen-substituted siloles respectively. We propose silyl-substituent and hydrogen atom effects to explain this via both experiments and theoretical calculations. It was discovered that trimethylsilyl substituents destroyed the p-interactions with the silole core and resulted in the non-fluorescence. Additionally, 1-chloro-1-H-2,3,4,5-tetraphenylsilole featuring strong fluorescences in both solid and solution states with high fluorescence quantum yields represents a new potential photoelectric material. This work not only reports the silole with strong fluorescences in both solid and solution states for the first time but also contributs to enrich the AIE research of siloles.

Synthesis and Spectroscopic Characterization of 2-(het)Aryl Perimidine Derivatives with Enhanced Fluorescence Quantum Yields

2019 ◽  
Vol 29 (2) ◽  
pp. 495-504 ◽  
Author(s):  
Marco Lamperti ◽  
Arianna Maria Giani ◽  
Angelo Maspero ◽  
Guglielmo Vesco ◽  
Alessandro Cimino ◽  
...  
Keyword(s):  
Spectroscopic Characterization ◽  
Quantum Yields ◽  
Enhanced Fluorescence ◽  
Fluorescence Quantum Yields

Photoinduced long-lived charge transfer excited states in AT-DNA strands

2016 ◽  
Vol 18 (31) ◽  
pp. 21241-21245 ◽  
Author(s):  
Lara Martinez-Fernandez ◽  
Yuyuan Zhang ◽  
Kimberly de La Harpe ◽  
Ashley A. Beckstead ◽  
Bern Kohler ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Electronic State ◽  
Excited States ◽  
Ir Spectrum ◽  
Excited Electronic State ◽  
Single Strand ◽  
Dna Strands ◽  
A Charge ◽  
First Time

The IR spectrum of a charge transfer (CT) excited electronic state in DNA has been computed for the first time, enabling assignment of the long-lived component of the transient IR spectrum of a d(AT)9 single strand to an A → T CT state.

Theoretical Characterization of the Lowest Triplet Excited States of the Tris-(1,4,5,8-tetraazaphenanthrene) Ruthenium Dication Complex

2008 ◽  
Vol 47 (12) ◽  
pp. 5259-5266 ◽  
Author(s):  
Fabienne Alary ◽  
Martial Boggio-Pasqua ◽  
Jean-Louis Heully ◽  
Colin J. Marsden ◽  
Patricia Vicendo
Keyword(s):  
Excited States ◽  
Theoretical Characterization ◽  
Triplet Excited States

Characterization of the Singlet and Triplet Excited States of 3-Chloro-4-methylumbelliferone

2011 ◽  
Vol 115 (30) ◽  
pp. 8392-8398 ◽  
Author(s):  
J. Sérgio Seixas de Melo ◽  
Catarina Cabral ◽  
João C. Lima ◽  
António L. Maçanita
Keyword(s):  
Excited States ◽  
Triplet Excited States
Sign in / Sign up

Export Citation Format

Share Document