scholarly journals Photophysical properties of the triangular [Au(HNCOH)]3 complex and its dimer

2020 ◽  
Vol 22 (18) ◽  
pp. 10314-10321 ◽  
Author(s):  
Jonas Greiner ◽  
Rashid R. Valiev ◽  
Dage Sundholm
Keyword(s):  
Rate Constants ◽  
Photophysical Properties ◽  
Radiative Rate

Radiative and non-radiative rate constants have been calculated for cyclic trinuclear gold(i) complexes within the Herzberg–Teller approximation.

scholarly journals First-principles calculations of anharmonic and deuteration effects on the photophysical properties of polyacenes and porphyrinoids

2020 ◽  
Vol 22 (39) ◽  
pp. 22314-22323 ◽  
Author(s):  
R. R. Valiev ◽  
R. T. Nasibullin ◽  
V. N. Cherepanov ◽  
G. V. Baryshnikov ◽  
D. Sundholm ◽  
...  
Keyword(s):  
Rate Constants ◽  
First Principles ◽  
Conversion Rate ◽  
Internal Conversion ◽  
Photophysical Properties ◽  
New Method ◽  
Lagrangian Multiplier ◽  
First Principles Calculations ◽  
Anharmonic Effects

A new method for calculating internal conversion rate constants (kIC), including anharmonic effects and using the Lagrangian multiplier technique, is proposed.

scholarly journals When two are better than one: bright phosphorescence from non-stereogenic dinuclear iridium(iii) complexes

2016 ◽  
Vol 45 (16) ◽  
pp. 6949-6962 ◽  
Author(s):  
Ruth E. Daniels ◽  
Stacey Culham ◽  
Michael Hunter ◽  
Marcus C. Durrant ◽  
Michael R. Probert ◽  
...  
Keyword(s):  
Rate Constants ◽  
Iridium Complexes ◽  
Bridging Ligands ◽  
Radiative Rate ◽  
Better Than

Tridentate N^C^N-coordinating ligands in combination with bis-N^C-bridging ligands give rise to achiral dinuclear iridium complexes displaying exceptionally high radiative rate constants.

Photophysical properties of self-assembling porphinatozinc and photoinduced electron transfer with fullerenes

2003 ◽  
Vol 07 (06) ◽  
pp. 405-414 ◽  
Author(s):  
Mitsunari Itou ◽  
Mamoru Fujitsuka ◽  
Yasuyuki Araki ◽  
Osamu Ito ◽  
Hiroaki Kido
Keyword(s):  
Electron Transfer ◽  
Rate Constants ◽  
Photoinduced Electron Transfer ◽  
Photophysical Properties ◽  
Zigzag Chain ◽  
Annihilation Process ◽  
Time Resolved ◽  
Axial Ligation ◽  
Self Assembling ◽  
Triplet Excited States

Photochemical and photophysical properties of self-assembling 5-(4-pyridyl)-10,15,20-triphenylporphinatozinc ( Znpyp 3) have been studied by steady-state and time-resolved absorption in addition to time-resolved fluorescence spectroscopy. Self-assembling oligomers ( Znpyp 3)n( n = 3 at 0.1 mM) were synthetically generated and assigned to a zigzag chain oligomeric structure, where n is dependant on the concentration and temperature. The lifetimes of the singlet and triplet excited states of ( Znpyp 3)n depend on n and the axial ligation. The rate-constant of ( Znpyp 3)n for the intermolecular T-T annihilation process was smaller than that of monomeric porphyrins. In the photoinduced electron-transfer to fullerenes ( C 60 and C 70), it was revealed that the rate-constants and efficiencies for ( Znpyp 3)n were essentially the same as those of the monomer. In the back electron transfer, the rate-constants of oligomers were smaller than that of the monomeric porphyrin, which suggests hole-delocalization along the porphyrin chain.

The structure, photochemical reactivity, and photophysical properties of adamantyl X-substituted aryl ethers and a comparison with the alkyl groups, methyl, tert-butyl, and allyl

2005 ◽  
Vol 83 (9) ◽  
pp. 1237-1252 ◽  
Author(s):  
A L Pincock ◽  
J A Pincock
Keyword(s):  
Excited State ◽  
Rate Constants ◽  
Singlet State ◽  
Bond Cleavage ◽  
Photophysical Properties ◽  
Excited Singlet State ◽  
Quantum Yields ◽  
Aryl Ether ◽  
Excited Singlet ◽  
Aryl Ethers

The structure, photophysical properties, and photochemistry of the adamantyl aryl ethers 1 in both methanol and cyclohexane have been examined. UV absorption spectra, 13C NMR chemical shifts, X-ray structures, and Gaussian calculations (B3LYP/6-31G(d)) indicate that these ethers adopt a 90° conformer in the ground state. In contrast, fluorescence spectra, excited singlet state lifetimes, and calculations (TDDFT) indicated a 0° conformer is preferred in the first excited singlet state S1. Irradiation in either solvent results in the formation of adamantane and the corresponding phenol as the major products, both derived from radical intermediates generated by homolytic cleavage of the ether bond. The 4-cyano substituted ether 1j was the only one to form the ion-derived product, 1-methoxyadamantane (16% yield), on irradiation in methanol. Rate constants of bond cleavage for these ethers from S1 were estimated by two different methods by comparison with the unreactive anisoles 2, but the effect of substituents was too small to determine structure–reactivity correlations. The temperature dependence of the quantum yields of the fluorescence of the unsub stituted, 4-methoxy and 4-cyano derivatives of 1 and 2 were also determined. These results indicated that the activated process for 1 was mainly bond cleavage for the 4-cyano substrate whereas for 2, it was internal conversion and intersystem crossing. Key words: aryl ether photochemistry, fluorescence, excited-state rate constants, excited-state temperature effects.

Phosphorescence of chloropentafluoroacetone at 77 °K

1970 ◽  
Vol 48 (18) ◽  
pp. 2937-2939 ◽  
Author(s):  
H. S. Samant ◽  
A. J. Yarwood
Keyword(s):  
Triplet State ◽  
Chlorine Atom ◽  
Rate Constants ◽  
Aliphatic Ketone ◽  
Radiative Rate

The phosphorescence of chloropentafluoroacetone at 77 °K is reported and the energy of the triplet state is estimated to be 74 kcal. The phosphorescence lifetimes and the relative phosphorescence yields of chloropentafluoroacetone and hexafluoroacetone at 77 °K were measured. The results show that substitution of a chlorine atom in the fluorinated aliphatic ketone changes the radiative and non-radiative rate constants from the triplet state at 77 °K by factors of about 1.7 and 2.3, respectively.

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