Comments on the interpretation of triplet excited-state decay data for the determination of the equilibrium constants in host–guest cyclodextrin complexes

1995 ◽  
pp. 2435-2436 ◽  
Author(s):  
Y. Liao ◽  
J. Frank ◽  
J. F. Holzwarth ◽  
C. Bohne
Keyword(s):  
Excited State ◽  
Equilibrium Constants ◽  
Triplet Excited State ◽  
Cyclodextrin Complexes ◽  
Decay Data ◽  
State Decay

scholarly journals Absorption, fluorescence, Raman spectroscopic and density functional theoretical studies on the singlet and triplet excited state decay of 3-amino-5-mercapto-1,2,4-triazole

RSC Advances ◽  
2020 ◽  
Vol 10 (23) ◽  
pp. 13442-13450
Author(s):  
Aimin Duan ◽  
Suosuo An ◽  
Jiadan Xue ◽  
Xuming Zheng ◽  
Yanying Zhao
Keyword(s):  
Biological Sciences ◽  
Excited State ◽  
Heterocyclic Compounds ◽  
Density Functional ◽  
Decay Process ◽  
Theoretical Studies ◽  
Triplet Excited State ◽  
Raman Spectroscopic ◽  
State Decay

The excited state decay process of N-heterocyclic compounds is attracting increasing attention due to their fundamental applications in pharmaceutical and biological sciences.

Temperature effects on xanthone–β-cyclodextrin binding dynamics

2011 ◽  
Vol 89 (3) ◽  
pp. 395-401 ◽  
Author(s):  
Tamara C. S. Pace ◽  
Cornelia Bohne
Keyword(s):  
Excited State ◽  
Complex Formation ◽  
Ground State ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Equilibrium Constants ◽  
Dissociation Rate ◽  
Activation Entropy ◽  
Triplet Excited State ◽  
Dissociation Rate Constants

The complexation dynamics of the triplet excited state of xanthone with β-cyclodextrin were studied at various temperatures between 10 and 50 °C. Association and dissociation rate constants were determined using the laser flash photolysis quenching methodology with Cu2+ as a quencher. The rate constants for the association and dissociation of triplet xanthone with β-cyclodextrin increased with temperature, while the equilibrium constant for the triplet excited state remained relatively constant. Equilibrium constants for the ground-state complexation of xanthone with β-cyclodextrin were determined from fluorescence studies at various temperatures. The ground-state binding efficiency decreased with temperature and was markedly greater than that of the triplet excited state at all temperatures. The enthalpy and entropy for the β-cyclodextrin complex formation of the ground and triplet excited states fall on the enthalpy–entropy compensation relationship previously established for cyclodextrin complexes. The activation enthalpies for the association and dissociation rate constants for triplet xanthone are similar. The activation entropy is favorable for the association process, whereas a negative activation entropy was measured for the dissociation process, suggesting that solvation plays a key role in the complex formation between xanthone and β-cyclodextrin.

Triplet excited-state characterization and determination of the photoionization mechanism of the antitumoral drug pazelliptine

1995 ◽  
Vol 90 (2-3) ◽  
pp. 95-102 ◽  
Author(s):  
M.P. Fontaine-Aupart ◽  
E. Renault ◽  
L. Brian ◽  
J.F. Delouis ◽  
M. Gardes̀-Albert
Keyword(s):  
Excited State ◽  
Triplet Excited State

Spectrophotometric study of the complexation equilibria of cadmium ions with 5-bromo and 5-chloro derivatives of 2-(2-pyridylazo)-5-diethylaminophenol (BrPADAP, ClPADAP)

1983 ◽  
Vol 48 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Miroslav Macka
Keyword(s):  
Equilibrium Constants ◽  
Spectrophotometric Study ◽  
Graphical Analysis ◽  
Optimal Conditions ◽  
Cadmium Ions ◽  
Brij 35 ◽  
Ethanol Medium ◽  
Triton X ◽  
Derivatives Of

The composition, optical characteristics, molar absorption coefficients and equilibrium constants of the reactions of formation of the ML and ML2 complexes of both reagents with cadmium(II) ions were determined by graphical analysis and numerical interpretation of the absorbance-pH curves by the modified SQUAD-G program. Optimal conditions were proposed for the spectrophotometric determination of Cd in 10% v/v ethanol medium in the presence of 0.1% w/v Triton X-100 or 1% w/v Brij 35. BrPADAP and ClPADAP are the most sensitive spectrophotometric reagents for the determination of cadmium(II) ions (ε = 1.28-1.44 . 105 mmol-1 cm2 at 560 nm and pH 8.0-9.5) with a high colour contrast in the reaction (Δλmax ~117 nm) and a selectivity similar to that of other N-heterocyclic azodyes (PAR, PAN, etc.).

Sign in / Sign up

Export Citation Format

Share Document