The toluidine blue ( TB) aggregation phenomenon in water solutions was investigated by UV-Vis absorption spectroscopy in a wide range of concentrations, from 10(-9) to 10(-2) M. The experimental data were fitted by assuming that the spectrum was due to the overlapping of the bands of six different aggregation species simultaneously present in solution. The model and the peak centres of the different species were hypothesized on the basis of exciton theory. All the spectra obtained were simultaneously processed thus allowing the derivation of the K constant, which was assumed to be the same for all the equilibria and which was found equal to 10 500. The epsilon spectra of the different aggregation species were also obtained. The overall TB spectrum may be mainly attributed to the H-type aggregation, although some of the species also show the J type bands. The structural features of TB and its dimeric aggregate were also investigated by means of molecular mechanics semi-empirical potential energy calculations. The results obtained for the dimer confirm the H type aggregation and show that the lowest energy model of the four possible is the one obtained by a mirror plane of symmetry containing the aromatic rings, in agreement with the x-ray diffraction data which will be presented in a forthcoming paper.

Toluidine blue: aggregation properties and structural aspects / D'Ilario, Lucio; Martinelli, Andrea. - In: MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING. - ISSN 0965-0393. - STAMPA. - 14:4(2006), pp. 581-595. [10.1088/0965-0393/14/4/003]

Toluidine blue: aggregation properties and structural aspects

D'ILARIO, LUCIO;MARTINELLI, Andrea
2006

Abstract

The toluidine blue ( TB) aggregation phenomenon in water solutions was investigated by UV-Vis absorption spectroscopy in a wide range of concentrations, from 10(-9) to 10(-2) M. The experimental data were fitted by assuming that the spectrum was due to the overlapping of the bands of six different aggregation species simultaneously present in solution. The model and the peak centres of the different species were hypothesized on the basis of exciton theory. All the spectra obtained were simultaneously processed thus allowing the derivation of the K constant, which was assumed to be the same for all the equilibria and which was found equal to 10 500. The epsilon spectra of the different aggregation species were also obtained. The overall TB spectrum may be mainly attributed to the H-type aggregation, although some of the species also show the J type bands. The structural features of TB and its dimeric aggregate were also investigated by means of molecular mechanics semi-empirical potential energy calculations. The results obtained for the dimer confirm the H type aggregation and show that the lowest energy model of the four possible is the one obtained by a mirror plane of symmetry containing the aromatic rings, in agreement with the x-ray diffraction data which will be presented in a forthcoming paper.
2006
dyes; equilibrium; methylene-blue; toluidine blue
01 Pubblicazione su rivista::01a Articolo in rivista
Toluidine blue: aggregation properties and structural aspects / D'Ilario, Lucio; Martinelli, Andrea. - In: MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING. - ISSN 0965-0393. - STAMPA. - 14:4(2006), pp. 581-595. [10.1088/0965-0393/14/4/003]
File allegati a questo prodotto
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/235807
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 49
  • ???jsp.display-item.citation.isi??? 49
social impact