Electrochemical and photophysical characterization of non-peripherally-octaalkyl substituted dichlorotin(IV) phthalocyanine and tetrabenzotriazaporphyrin compounds

2007 ◽  
Vol 11 (10) ◽  
pp. 761-770 ◽  
Author(s):  
Samson Khene ◽  
Andrew N. Cammidge ◽  
Michael J. Cook ◽  
Tebello Nyokong
Keyword(s):  
Cyclic Voltammetry ◽  
Quantum Yield ◽  
Triplet State ◽  
Electrochemical Behavior ◽  
Heavy Atom ◽  
Quantum Yields ◽  
Redox Processes ◽  
Central Metal ◽  
Atom Effect

Three non-peripherally substituted tin(IV) macrocylic compounds, octahexylphthalocyaninato dichlorotin(IV) (3a), octahexyltetrabenzo-5,10,15- triazaporphyrinato dichlorotin(IV) (3b) and octadecylphthalocyaninato dichlorotin(IV) (3c) were synthesized and their photophysical and electrochemical behavior studied. Complex 3b, containing a CH group in place of one of the aza nitrogen atoms of the phthalocyanine core, shows a split Q-band due to its lower symmetry. The triplet state quantum yields were found to be lower than would be expected on the basis of the heavy atom effect of tin as the central metal for phthalocyanine derivatives (3a and 3c). In contrast, 3b shows a triplet quantum yield Φ T = 0.78. The triplet state lifetimes were solvent dependent, and were higher in tetrahydrofuran than in toluene. Cyclic voltammetry and spectroelectrochemistry of the complexes revealed only ring-based redox processes.

scholarly journals Phosphoreszenzeigensch aften von Methyl-, Chlor- und Brom-Derivaten des [2.2] Paracyclophans

1987 ◽  
Vol 42 (9) ◽  
pp. 1041-1042 ◽  
Author(s):  
H. Hopf ◽  
E. Hermann
Keyword(s):  
Triplet State ◽  
Fluorescence Spectra ◽  
Heavy Atom ◽  
The Other ◽  
Quantum Yields ◽  
Heavy Atom Effect ◽  
Chloro Derivatives ◽  
Derivatives Of ◽  
Atom Effect

Phosphorescence and fluorescence spectra, quantum yields of phosphorescence and fluorescence as well as phosphorescence lifetimes have been measured of six methyl-, chloro- and bromo-derivatives of [2.2] paracyclophane in ethanol at 77 K. While the chloro-derivatives as well as dibromo-paracyclophane exhibit a normal internal heavy-atom effect behaviour the momobromo-compound shows anomalies. These possibly indicate that in the monobromo-compound an additional pathway of the radiationless deactivation of the lowest triplet state is effective which does not occur with the other compounds.

Zum äußeren Schweratom-Effekt der Phosphoreszenz in nicht-fluoreszierenden aromatischen Verbindungen / The External Heavy-Atom-Effect of Phosphorescence in Non-fluorescing Aromatic Compounds

1973 ◽  
Vol 28 (11) ◽  
pp. 1869-1870
Author(s):  
M. Zander
Keyword(s):  
Triplet State ◽  
Aromatic Compounds ◽  
Heavy Atom ◽  
Quantum Yields ◽  
Naphthalene Derivatives ◽  
Heavy Atom Effect ◽  
Atom Effect

Phosphorescence quantum yields of six non-fluorescing naphthalene derivatives have been measured in ethanol and ethanol-ethylbromide 1:1 at 77 °K. The observed enhancement of phosphorescence yield of four of these in the heavy atom solvent is explained with the assumption that the rate of the phosphorescence transition is increased relatively to the radiationless desactivation of the triplet state.

Synthesis and Characterization of 2,5-bis[(3,4-ethylenedioxy)thien-2-yl]-3-Substituted Thiophenes

2002 ◽  
Vol 736 ◽  
Author(s):  
Michael F. Pepitone ◽  
Kalya Eaiprasertsak ◽  
Stephen S. Hardaker ◽  
Richard V. Gregory
Keyword(s):  
Cyclic Voltammetry ◽  
Quantum Yield ◽  
Electrochemical Behavior ◽  
Electronic Device ◽  
Blue Emission ◽  
Synthesis And Characterization ◽  
Emission Characteristics ◽  
Potential Cycling ◽  
Device Applications

ABSTRACTSynthesis and functionalization of 3-bromothiophene afforded novel 2,5-bis[(3,4-ethylenedioxy)thien-2-yl]-)-3-substituted thiopehene monomers with blue emission characteristics and having a quantum yield of 3–5%. Cyclic voltammetry was employed to investigate the electrochemical behavior of the four monomers reported here. Polymer films were deposited by repeated potential cycling. These materials are considered for use in tailoring properties in opto-electronic device applications.

Effects of central metal on the photophysical and photochemical properties of non-transition metal sulfophthalocyanine

2005 ◽  
Vol 09 (02) ◽  
pp. 121-129 ◽  
Author(s):  
Abimbola Ogunsipe ◽  
Tebello Nyokong
Keyword(s):  
Quantum Yield ◽  
Transition Metal ◽  
Metal Ion ◽  
Heavy Atom ◽  
Central Metal ◽  
Dynamic Quenching ◽  
Yield Values ◽  
Photochemical Properties ◽  
Dynamic Components ◽  
Atom Effect

The photophysical and photochemical properties and quenching (by 1,4-benzoquinone) of metallophthalocyanine sulfonates of aluminium ( AlPcSmix), zinc ( ZnPcSmix), silicon ( SiPcSmix), germanium ( GePcSmix) and tin ( SnPcSmix) are presented. The quantum yield values of fluorescence (ΦF), triplet state (ΦT), singlet oxygen (ΦΔ) and photodegradation (Φd) were determined and the observed trends in their variation among the complexes discussed in terms of aggregation and the heavy atom effect. 1,4-benzoquinone effectively quenched the fluorescence of the complexes. Quenching analyses gave positive deviations from Stern-Volmer behavior, suggesting the existence of static quenching in addition to dynamic quenching. The static and dynamic components of the quenching were separated using a modified Stern-Volmer equation and the “sphere of action quenching model”. The quenching constant was found to be a function of the radius of the central metal ion.

Löschung der Perylen-Fluoreszenz durch Ag+ -Ionen / Quenching of the Perylene Fluorescence by Ag+-Ions

1983 ◽  
Vol 38 (6) ◽  
pp. 698-700 ◽  
Author(s):  
H. Dreeskamp ◽  
A. Läufer ◽  
M. Zander
Keyword(s):  
Triplet State ◽  
Dynamic Process ◽  
Aromatic Compounds ◽  
Heavy Atom ◽  
Silver Ions ◽  
Intersystem Crossing ◽  
Fluid Solution ◽  
Long Wavelength ◽  
Wavelength Emission ◽  
Atom Effect

The fluorescence of perylene in fluid solution (λ0.0 = 440 nm) is quenched by silver ions in a dynamic process according to a Stern-Volmer kinetics (kq = 2 · 109 [1 • mol-1 · sec-1], in ethanol at 295 K). Simultaneously an unstructured long-wavelength emission (λmax ≈ 470 nm) appears which we assign to a perylene/Ag+ exciplex. A similar emission is observed when other polvcyclic aromatic compounds (PAC) are used, whose fluorescence as in the case of perylene is not easily quenched in an external heavy atom effect by iodopropane (kq ≦ 106). In these cases the excited PAC/Ag+ complex is long-lived enough to emit fluorescence since the intersystem crossing to the triplet system is slow due to the absence of an energetically favorable accepting triplet state

An exceptionally long-lived triplet state of red light-absorbing compact phenothiazine-styrylBodipy electron donor/acceptor dyads: a better alternative to the heavy atom-effect?

2020 ◽  
Vol 56 (11) ◽  
pp. 1721-1724 ◽  
Author(s):  
Yuqi Hou ◽  
Qingyun Liu ◽  
Jianzhang Zhao
Keyword(s):  
Charge Transfer ◽  
Triplet State ◽  
Electron Donor ◽  
Heavy Atom ◽  
Red Light ◽  
Intersystem Crossing ◽  
Spin Orbital ◽  
Heavy Atom Effect ◽  
Donor Acceptor ◽  
Atom Effect

Heavy atom-free dyads showing a red light-absorbing and exceptionally long-lived triplet state based on a spin–orbital charge transfer intersystem crossing mechanism.

Triplet state quantum yields for some arom atic hydrocarbons and xanthene dyes in dilute solution

1967 ◽  
Vol 299 (1458) ◽  
pp. 348-353 ◽  
Keyword(s):  
Triplet State ◽  
State Formation ◽  
Heavy Atom ◽  
Quantum Yields ◽  
Triplet States ◽  
Dilute Solution ◽  
Perturbation Techniques ◽  
Excited Singlet ◽  
Xanthene Dyes ◽  
Extinction Coefficients

Quantum yields of triplet state formation and extinction coefficients of the triplet states have been determined by direct depletion methods for solutions of anthracene, phenanthrene, 1,2,5,6-dibenzanthracene, fluorescein, dibromofluorescein, eosin and erythrosin. The values obtained for the hydrocarbons are in reasonable agreement with those obtained by other workers using energy transfer and heavy atom perturbation techniques. In all cases which we have studied, the sum of the quantum yields of fluorescence and triplet state formation is equal to unity within the limits of experimental error, showing that radiationless transfer from the excited singlet to the ground state is negligible.

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