Treatment of a number of 4-substituted arylazobenzenes (-H, -Me, -CF3, -Br, -F and -OMe) with Et2O.BF3 in dry chloroform solution afforded chromophores that exhibited significant hyper- (log 3 4.41-4.60) and bathochromic shifts (lambdamax 416-473) in electronic spectra, together with significant shifts in their 1H NMR and 13C NMR spectra, indicating the formation of novel chemical species. It is proposed that complexes are formed between the azo dyes and the Lewis acid, similarly to what happens for the well-known protic acids. The equilibrium constants (log K ) of the proposed complexes have been calculated from the experimental data. Numerical modelling has also been performed to investigate the nature of the new systems, revealing a correlation between the electronic levels of the azo dye and the ones of the BF3.OEt2.

A. Fraleoni-Morgera, L. Giorgini, P. Zanirato (2008). [ArylazobenzeneeBF3] dyes: Electronic absorption and NMR spectroscopic evidence for a novel class of dyes stable in aprotic solvents. DYES AND PIGMENTS, 76/2, 394-399 [10.1016/j.dyepig.2006.09.005].

[ArylazobenzeneeBF3] dyes: Electronic absorption and NMR spectroscopic evidence for a novel class of dyes stable in aprotic solvents

FRALEONI MORGERA, ALESSANDRO;GIORGINI, LORIS;ZANIRATO, PAOLO
2008

Abstract

Treatment of a number of 4-substituted arylazobenzenes (-H, -Me, -CF3, -Br, -F and -OMe) with Et2O.BF3 in dry chloroform solution afforded chromophores that exhibited significant hyper- (log 3 4.41-4.60) and bathochromic shifts (lambdamax 416-473) in electronic spectra, together with significant shifts in their 1H NMR and 13C NMR spectra, indicating the formation of novel chemical species. It is proposed that complexes are formed between the azo dyes and the Lewis acid, similarly to what happens for the well-known protic acids. The equilibrium constants (log K ) of the proposed complexes have been calculated from the experimental data. Numerical modelling has also been performed to investigate the nature of the new systems, revealing a correlation between the electronic levels of the azo dye and the ones of the BF3.OEt2.
2008
A. Fraleoni-Morgera, L. Giorgini, P. Zanirato (2008). [ArylazobenzeneeBF3] dyes: Electronic absorption and NMR spectroscopic evidence for a novel class of dyes stable in aprotic solvents. DYES AND PIGMENTS, 76/2, 394-399 [10.1016/j.dyepig.2006.09.005].
A. Fraleoni-Morgera; L. Giorgini; P. Zanirato
File in questo prodotto:
Eventuali allegati, non sono esposti

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/11585/32390
 Attenzione

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

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 4
  • ???jsp.display-item.citation.isi??? 4
social impact