Electronic spectra of phenoxazine dyestuffs and substituent effects on the position of long-wave absorption bands

1977 ◽  
Vol 42 (4) ◽  
pp. 1332-1337 ◽  
Author(s):  
V. Stužka ◽  
E. Šindelářová
Keyword(s):  
Electronic Spectra ◽  
Substituent Effects ◽  
Absorption Bands ◽  
Wave Absorption ◽  
Long Wave

Tunable Optical Properties of Ag–TiO2 Nanorod Composites Based on Interparticle Plasmon Coupling

NANO ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. 1650110 ◽  
Author(s):  
Yong Zhang ◽  
Fa-Min Liu
Keyword(s):  
Optical Properties ◽  
Reduction Method ◽  
Plasmon Coupling ◽  
Silver Acetate ◽  
Absorption Bands ◽  
Photochemical Reduction ◽  
Wave Absorption ◽  
Long Wave ◽  
Ag Particles ◽  
Tunable Optical Properties

The metal–semiconductor composites with unique optical properties are highly desirable. Here we report that Ag–TiO2 nanorod composites with two distinctive absorption peaks exhibit tunable plasmon coupling behaviors. The intensity of the long-wave absorption could be enhanced by modifying the geometry of TiO2 particles, while such absorption is due to the plasmon coupling between the Ag particles. The long-wave absorption bands can be tuned by varying the reaction time and changing the amount of silver acetate. Furthermore, the Ag–TiO2 composites were also prepared by photochemical reduction method which confirmed the previous properties. These results may help to design metal–semiconductor systems with desirable optical properties.

Solvent and substituent effects on the electronic spectra of 3-arylazo-imidazo[1,2-b]pyrazolo[4,3-d]-pyridazines

2012 ◽  
Vol 36 (10) ◽  
pp. 615-618 ◽  
Author(s):  
Ahmad S. Shawali ◽  
Thoraya A. Farghaly ◽  
Tarek M.S. Nawar
Keyword(s):  
Electronic Spectra ◽  
Substituent Effects

Dihydronaphthalenone Carboxylates - Spectral Characteristics and Structure

1997 ◽  
Vol 52 (5) ◽  
pp. 457-461 ◽  
Author(s):  
Sn. Bakalova ◽  
A. Georgieva ◽  
P. Nikolov ◽  
E. Stanoeva
Keyword(s):  
Ir Spectra ◽  
Quantum Chemical Calculations ◽  
Electronic Spectra ◽  
Quantum Chemical ◽  
Substituent Effect ◽  
Methyl Esters ◽  
Spectral Characteristics ◽  
Absorption Bands ◽  
Tautomeric Forms ◽  
Luminescence Characteristics

Abstract The absorption and luminescence characteristics of a group of newly synthesized methyl esters of 2-alkyl (p-substituted-aryl) -aminomethylene-3,4-dihydro-1(2 H)-naphthalenone-4-carboxylic acids have been investigated. The studied compounds may exist in three tautomeric forms. On the basis of comparison of their electronic spectra to those of similar substances, the observed substituent effect on the position of the UV-VIS absorption bands, the IR spectra and the results of PPP-SCF-CI quantum-chemical calculations it is concluded that the keto tautomer predominates in solution.

Substituent effects on the electronic spectra of aromatic hydrocarbons I. A comparison of the localized-orbital and iso-conjugate-hydrocarbon models for interpreting the spectra of amino- and nitrobenzenes

1964 ◽  
Vol 278 (1372) ◽  
pp. 57-63 ◽  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Configuration Interaction ◽  
Electronic Spectra ◽  
Substituent Effects ◽  
Phenyl Group ◽  
Zero Order ◽  
Wave Functions ◽  
Localized Orbital

Two models are used to analyze the spectra of aniline and nitrobenzene. These are the localized-orbital model, in which there is no delocalization of the electrons between the phenyl group and the substituent, and the iso-conjugate-hydrocarbon model, in which there is complete delocalization. Neither model is very satisfactory with zero-order wave functions and energies. Both give a satisfactory interpretation of the spectra if configuration interaction is taken into account but the localized-orbital model is rather better for calculating energies. The localized-orbital model is also more readily applied to polysubstituted benzenes.

The Structure of Polyisoprenes. V. Ultraviolet Absorption Spectra of Certain Carbalkoxy-Substituted 1,5-Dienes, and the Charge-Resonance Spectra of Glutaconic Ester Enolate Ions

1946 ◽  
Vol 19 (1) ◽  
pp. 23-33
Author(s):  
L. Bateman ◽  
H. P. Koch
Keyword(s):  
Absorption Band ◽  
Absorption Spectra ◽  
Special Interest ◽  
Crystalline State ◽  
Marked Change ◽  
Cyanine Dyes ◽  
Structural Type ◽  
Wave Absorption ◽  
Long Wave ◽  
Ester Enolate

Abstract Spectral evidence supports the conclusion reached in Part IV that ring-chain mesomerism in methyl and ethyl Δ1,5-hexadiene-l,1,3,3,4,4,6,6-octacarboxylates is nonexistent in solution, just as in the crystalline state. The data are not inconsistent with chain hyperconjugation in these molecules. The marked change in structural type that follows the addition of one molecule of hydrogen or hydrolytic reagent has been verified spectrographically. The spectra of methyl and ethyl α,γ-dicarboxyglutaconic esters and their sodium and cupric derivatives have been measured in various solvents, and their tautomeric behavior compared with that of other keto-enols. Of special interest is the intense long-wave absorption band of the enolate ions, which are recognized as simple structural analogs of the cyanine dyes giving rise to similar charge-resonance spectra. A preliminary comment is made on the present accepted structure of ethyl 6-ethoxy-α-pyrone-3:5-dicarboxylate.

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