Theoretical investigation of the vibronic phosphorescence spectra and quantum yields for iridium(III) complexes with 2-(2,5,2′,3′,4′,5′,6′-heptafluoro-biphenyl-4-yl)-pyridine as the primary ligand

2019 ◽  
Vol 216 ◽  
pp. 179-189 ◽  
Author(s):  
Jiayi Guo ◽  
Xiao Pan ◽  
Junfeng Li ◽  
Wenpeng Wu ◽  
Jinglai Zhang
Keyword(s):  
Theoretical Investigation ◽  
Quantum Yields ◽  
Phosphorescence Spectra

Luminescence of 5-Phenyltetrazole and its Derivatives. Part II. Phosphorescence

1984 ◽  
Vol 39 (6) ◽  
pp. 556-559 ◽  
Author(s):  
I. Gryczyński ◽  
A. Kawski ◽  
Z. Grzonka ◽  
A. Rażyńska
Keyword(s):  
Triplet State ◽  
Quantum Yields ◽  
Intersystem Crossing ◽  
Thermal Deactivation ◽  
Fluorescence Quantum Yields ◽  
Radiative Transitions ◽  
Polyvinyl Alcohol Film ◽  
Methyl Derivatives ◽  
Temperature Responses ◽  
Phosphorescence Spectra

The phosphorescence spectra, mean lifetimes of phosphorescence and ratios of phosphorescence/ fluorescence quantum yields have been measured for 5-phenyltetrazole and its three methyl derivatives in a polyvinyl alcohol film over the temperature range of (77-250) K. Temperature responses of the non-radiative intersystem crossing constant. KST, and the non-radiative triplet state deactivation constant, km, have been investigated on the basis of these measurements. The energy of activation for the non-radiative transitions has been determined. With the methyl 5-phenyltetrazoles, the thermal deactivation of the triplet state, contrary to the intersystem crossing, has been found to be influenced by the position of the methyl substituent in the phenyl ring.

Vibronic Activity in the Phosphorescence Spectra of Disklike Aromatic Molecules:  A Combined Experimental and Theoretical Investigation

1998 ◽  
Vol 102 (49) ◽  
pp. 10007-10016 ◽  
Author(s):  
D. Baunsgaard ◽  
N. Harrit ◽  
F. Negri ◽  
G. Orlandi ◽  
J. Frederiksen ◽  
...  
Keyword(s):  
Theoretical Investigation ◽  
Aromatic Molecules ◽  
Phosphorescence Spectra

The mutual noncovalent interactions based on metallophilic cluster and anions: A theoretical investigation of the molecular structure and spectroscopic properties of Host–Guest complexes

2019 ◽  
Vol 18 (06) ◽  
pp. 1950028
Author(s):  
Xiao-Ping Yang ◽  
Hui-Xue Li ◽  
Kun Yuan ◽  
Guo-Fang Zuo ◽  
Zhi-Feng Li
Keyword(s):  
Molecular Structure ◽  
Theoretical Investigation ◽  
Noncovalent Interactions ◽  
Spectroscopic Properties ◽  
Phosphorescence Spectra ◽  
Metallophilic Interactions

The d[Formula: see text] metallophilic host clusters [Au(NHC)2][Formula: see text] [M(CN)2][Formula: see text] [Au(NHC)2][Formula: see text](NHC [Formula: see text] N-heterocyclic carbene, [Formula: see text], Ag) with high phosphorescence are synthesized recently and their phosphorescent modulation by solvents is investigated in theory. In this paper, the guest anions (F−, Cl−, Br−, NO[Formula: see text], and BF[Formula: see text] are used to elucidate their effects on metallophilic interactions and phosphorescence of hosts, and also they served as the probes to study the recognition characters of metallophilic hosts. The calculation shows that the guest anions can mutually interact with the host clusters and further, which can modulate the metallophilic Au[Formula: see text]M distances and the phosphorescence spectra of the hosts.

Effect of Substituents on the Viscosity Dependence of Fluorescence and on the S1 - T1 Energy Gap of Donor-Acceptor Substituted Trans-Stilbenes

1997 ◽  
Vol 52 (12) ◽  
pp. 837-842 ◽  
Author(s):  
Hans E. Wilhelm ◽  
Horst Gebert ◽  
Wolfgang Regenstein
Keyword(s):  
Energy Gap ◽  
Quantum Yields ◽  
Intersystem Crossing ◽  
Triplet Energy ◽  
Fluorescence Quantum Yields ◽  
Donor Acceptor ◽  
Fluorescence And Phosphorescence Spectra ◽  
Viscosity Dependence ◽  
Fluorescence And Phosphorescence ◽  
Phosphorescence Spectra

The dependence of fluorescence quantum yields and S1-lifetimes of donor-acceptor substituted trans-stilbenes on temperature was measured in the temperature range from 298 to 100 K, using solutions of stilbenes in 3-methylpentane (3-MP). Measurements of fluorescence and phosphorescence spectra show that the triplet energy is almost independent of the acceptor. The S1-energy and the S1-T1 energy gap decrease with increasing acceptor strength. For all compounds intersystem crossing (ISC) S1 → T1, is negligible

Einfluß von Chlorsubstitution auf die El ektronenspektren von Biphenyl

1972 ◽  
Vol 27 (5) ◽  
pp. 756-759 ◽  
Author(s):  
H. Dreeskamp ◽  
O. Hutzinger ◽  
M. Zander
Keyword(s):  
Excited State ◽  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Emission Spectra ◽  
Liquid Solution ◽  
Quantum Yields ◽  
Decay Times ◽  
Fluorescence And Phosphorescence Spectra ◽  
Fluorescence And Phosphorescence ◽  
Phosphorescence Spectra

Abstract Absorption spectra in liquid solution, fluorescence and phosphorescence spectra, phosphores-cence quantum yields, phosphorescence to fluorescence quantum yield ratios, and phosphorescence decay times of 9 chloro substituted biphenyls dissolved in low temperature EPA glass were in-vestigated. The emission spectra of sterically unhindered systems are structured and significantly Stokes-shifted. Ortho substitution shifts the conjugation band in absorption as well as the un-structured fluorescence and phosphorescence bands to shorter wave lengths presumably by pre-venting the system from attaining a planar excited state. Chloro substitution which increases the rate constant of phosphorescence in the order meta < para < ortho, is nearly additive for multiple substituted systems and is correlated to the MO coefficients at the chloro substituted position in the absence of steric hindrance

Zur Photolumineszenz von Benzologen des Thiophens

1985 ◽  
Vol 40 (5) ◽  
pp. 497-502 ◽  
Author(s):  
Maximilian Zander
Keyword(s):  
Energy Gap ◽  
Heavy Atom ◽  
Phosphorescence Spectrum ◽  
Quantum Yields ◽  
Triplet States ◽  
Fluorescence And Phosphorescence Spectra ◽  
Atom Effect ◽  
Fluorescence And Phosphorescence ◽  
Phosphorescence Spectra ◽  
Hydrocarbon Fragment

Fluorescence and phosphorescence spectra, fluorescence and phosphorescence quantum yields and phosphorescence lifetimes of the benzologues I -V of thiophene have been measured in ethanol at 77 K. By comparing the energies of the lowest triplet states of the molecules with those of corresponding hydrocarbons it is concluded that the sulphur atoms act like substituents and are not equivalent to aromatic double bonds. The rate of the radiationless deactivation of the lowest triplet state depends on the energy gap Δ E(T1 - S0) in accordance with the Siebrand relation. An unexpected small intraannullar heavy-atom effect of the sulphur is observed in 2,2′-bis-benzo[b]thienyl (II), a strongly fluorescing compound. As the most likely explanation it is concluded from experiments that in II the interaction between the heavy-atom and the π-MO’s of the hydrocarbon fragment (1,4-biphenylbutadiene) is much smaller compared to that in other structurally related benzologues of thiophene. External heavy-atom perturbers (AgClO4, CH3J) have a strong influence on the vibronic structure of the phosphorescence spectrum of IV.

Theoretical Investigation on the Kinetics and Mechanism of the Synthesis of Fluorescent 3,8-Disubstituted-3H-Imidazo [4,5-a] Acridine-11-Carbonitriles

2016 ◽  
Vol 41 (4) ◽  
pp. 365-370 ◽  
Author(s):  
Fatemeh Zonozi ◽  
Mehdi Pordel ◽  
S. Ali Beyramabadi ◽  
Ali Morsali
Keyword(s):  
Theoretical Investigation ◽  
Density Functional ◽  
Theoretical Study ◽  
Fluorescent Dyes ◽  
Quantum Yields ◽  
Electrophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Dft Methods ◽  
Functional Theory ◽  
Plausible Mechanism

3,8-Disubstituted-3H-imidazo[4,5-a]acridine-11-carbonitriles show very interesting optical properties. In some cases, they have higher quantum yields compared to well-known fluorescent dyes such as fluorescein. Hitherto, no detailed theoretical study has been reported on the mechanism of the synthesis of the titled compounds, hence an accurate and detailed theoretical investigation on the synthesis of these dyes is desirable. In this paper, density functional theory (DFT) methods have been employed to investigate the most reasonable mechanism in formation of these fluorophores. All species and related transition states were optimised and the relative energies of all species and the activation energies for all proposed mechanisms were obtained. Comparing the Ea values of all pathways reveals that intramolecular electrophilic aromatic substitution is the most plausible mechanism for the cyclisation reaction in the preparation of these dyes. Also, the effects of substituents in positions 3 and 8 were investigated and the results show that electron-donor substituents can reduce the activation energy for formation of the σ complex in the electrophilic aromatic substitution.

Verzögerte Fluoreszenz und Phosphoreszenz in reinen Naphthalin-Kristallen

1971 ◽  
Vol 26 (5) ◽  
pp. 787-793 ◽  
Author(s):  
K. W. Benz ◽  
H. Port ◽  
H. C. Wolf
Keyword(s):  
Light Intensity ◽  
Line Width ◽  
Room Temperature ◽  
Delayed Fluorescence ◽  
Triplet Exciton ◽  
Quantum Yields ◽  
Triplet Excitation ◽  
Intensity Dependence ◽  
Phosphorescence Spectra

In extremely purified naphthalene crystals triplet exciton lifetimes up to 500 msec at room temperature were measured. The triplet annihilation coefficient is measured from an analysis of the light intensity dependence of delayed fluorescence as γ = 3.5 · IO-12 cm3 sec-1 at 300 °K and at 135 °K. The quantum yields in the weak excitation limit at room temperature are ηDF = (3 ± 0.6) · 10-3 for delayed fluorescence and ηp = (1.2 ± 0.3) • 1O-3 for prompt phosphorescence, both after triplet excitation. The phosphorescence spectra of naphthalene and perdeuteronaphthalene crystals are analyzed between 300 and 50 °K. The line width decreases from 270 cm-1 at 300 °K down to 42 cm-1 at 60 °K.

scholarly journals The Phosphorescence Spectra of Triphenylene and Truxene: A Combined Experimental and Theoretical Investigation of the Vibronic Structure

1999 ◽  
Vol 19 (1-4) ◽  
pp. 349-351 ◽  
Author(s):  
D. Baunsgaard ◽  
M. El Balsami ◽  
J. Frederiksen ◽  
N. Harrit ◽  
F. Negri ◽  
...  
Keyword(s):  
Quantum Chemical Calculations ◽  
Theoretical Investigation ◽  
Ground State ◽  
Quantum Chemical ◽  
Vibronic Structure ◽  
Phosphorescence Spectra

The phosphorescence spectra of triphenylene and truxene, recorded in glassy solvents at 77 K, are presented. Their vibronic structure is interpreted on the basis of intensities computed with the help of quantum-chemical calculations. The agreement between observed and simulated intensities is very satisfactory and contributes to improve and complete the assignment of ground state frequencies of the two disk-like molecules.

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