Changes induced by solvent polarity in electronic absorption spectra of some azo disperse dyes

2010 ◽  
Vol 157 (1) ◽  
pp. 13-17 ◽  
Author(s):  
A. Airinei ◽  
M. Homocianu ◽  
D.O. Dorohoi
2003 ◽  
Vol 07 (02) ◽  
pp. 105-111 ◽  
Author(s):  
Kazuaki Hatsusaka ◽  
Kazuchika Ohta

Spectroscopic properties of discotic liquid crystalline bis[octakis(3,4-dialkoxyphenoxy)-phthalocyaninato]lutetium(III) complexes, {[( C n O )2 PhO ]8 Pc }2 Lu (n = 12: 2a and n = 13: 2b), were investigated by recording electronic absorption spectra in the region of 250-2600 nm under three different conditions; solution, mixed solvent solutions, and a thin film at various temperatures. An intermolecular charge transfer (CT) band was found at about 2000-2100 nm both for the n-hexane solution and the thin film. It was established for the first time from the solvent-polarity-dependent and temperature-dependent electronic absorption spectra that the intermolecular CT band is attributable to molecular aggregation.


2011 ◽  
Vol 312 ◽  
pp. 37-59 ◽  
Author(s):  
Mamdouh S. Masoud ◽  
Ahmed M. Hindawy ◽  
Amina A. Soayed ◽  
Marwa Y. Abd El-Kaway

2010 ◽  
Vol 29 (1) ◽  
pp. 43 ◽  
Author(s):  
Mirjana Jankulovska ◽  
Lidija Šoptrajanova ◽  
Ilinka Spirevska ◽  
Katica Čolančevska-Ragenoviќ ◽  
Saško Ristovski

The influence of the polarity of the solvent and hydrogen bonding on the electronic absorption spectra of some previously synthesized substituted 1,2,4-triazoline-3-thiones was studied. The electronic absorption spectra of investigated compounds were recorded in the region from 190 nm to 360 nm in eight protic (water, ethylene glycol, methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol and tert-butanol) and five aprotic (acetonitrile, chloroform, dimethylsulfoxide, dimethylformamide and dioxane) solvents. Their absorption maxima appeared in the region between 250 nm and 260 nm as a result of the electron transitions in the 1,2,4-triazoline-3-thione ring. Using the method of linear solvation energy relationships (LSER), the effects of solvent polarity and hydrogen bonding on the electronic absorption spectra were interpreted. The results have shown that the influence of the aprotic solvents is more significant compared to that of the protic solvents.


2020 ◽  
Vol 85 (10) ◽  
pp. 1253-1264
Author(s):  
Umar Ameuru ◽  
Mohammed Yakubu ◽  
Kasali Bello ◽  
Peter Nkeonye ◽  
Azim Halimehjani

A series of monoazo disperse dyes were synthesized by coupling diazotized 4-amino-N-dodecyl-1,8-naphthalimide with N,N-dialkyl anilines and naphthol derivatives. The synthesized intermediates and the dyes were characterized using FTIR, 1H-NMR, 13C-NMR, mass spectroscopy and elemental analysis (CHN). Visible absorption spectra of the dyes were examined in solvents of different polarities. The electronic absorption spectra cover a wavelength (?max) range of 515-535 nm in DMF at uniformly absorption intensity between 1.59-3.00?104 L mol-1 cm-1. The dyes gave deep and bright intense hues of light violet, maroon, pink and neon red on polyester fabrics. The dyes generally showed good washing and perspiration rating but poor to moderate light fastness properties on woven polyester fabric and could be recommended for commercial outlets.


1984 ◽  
Vol 49 (3) ◽  
pp. 680-683 ◽  
Author(s):  
Bohumil Hájek ◽  
Dagmar Sýkorová ◽  
Jiří Chyba

The λ-C1-cis(N), δ-C1-cis(N), λ-C2-cis(N) and δ-C2-cis(N) isomers of the complex K[Co((S)-Pro)2CO3] were chromatographically separated and characterized by their electronic absorption spectra and CD spectra.


1995 ◽  
Vol 60 (10) ◽  
pp. 1621-1633 ◽  
Author(s):  
Stanislav Böhm ◽  
Mojmír Adamec ◽  
Stanislav Nešpůrek ◽  
Josef Kuthan

Molecular geometries of 2,4,4,6-tetraphenyl-4H-pyran (Ia), 4,4-(biphenyl-2,2e-diyl)-2,6-diphenyl-4H-pyran (Ib) and their heterocyclic isomers II-V were optimized by the PM3 method and used for the calculation of electronic absorption spectra by the CNDO/S-CI procedure. Comparison of the theoretical data with experimental UV-VIS absorption spectra made possible to select hypervalent molecules IIIa, IIIb, IVa and IVb being responsible for the photocolouration of 4H-pyrans Ia, Ib, while compounds Va, Vb, VI and VII come into account as possible photodegradation products. The bleaching process of the UV illuminated compound Ia is analyzed in terms of dispersive first-order reaction kinetics.


1998 ◽  
Vol 63 (5) ◽  
pp. 628-635 ◽  
Author(s):  
Jana Holubová ◽  
Zdeněk Černošek ◽  
Ivan Pavlík

The effect of the halide ligand on the bonding of niobium in niobocene dichloride and niobocene diiodide was investigated. The electronic absorption spectra of the two compounds in the range of d-d transitions were resolved into four bands corresponding to transitions of the d1 electron between five frontier orbitals in a molecule of symmetry point group C2v. The energies of the frontier molecular orbitals were determined relatively to the energy of the orbitals in the spherically symmetric ligand field formed by the appropriate halide ligands. The effect of the halide ligands on the spin-orbital interaction of the HOMO orbital is discussed qualitatively on the basis the ESR spectra.


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