A resonance Raman spectroscopic study of the protonation of 4-(phenylazo)-diphenylamine and 4-(4′-nitrophenylazo)-diphenylamine in solution and adsorbed on oxide surfaces

Autor:	Louise D. MacGregor, Trevor J. Dines, Colin H. Rochester
Rok vydání:	2004
Předmět:	Inorganic chemistry Diphenylamine Oxide General Physics and Astronomy Protonation Resonance (chemistry) chemistry.chemical_compound symbols.namesake Adsorption chemistry Ab initio quantum chemistry methods symbols Physical chemistry Molecule Physical and Theoretical Chemistry Raman spectroscopy
Zdroj:	Phys. Chem. Chem. Phys.. 6:4096-4104
ISSN:	1463-9084 1463-9076
Popis:	The adsorption of 4-(phenylazo)-diphenylamine (PADA) and 4-(4′-nitrophenylazo)-diphenylamine (Disperse Orange 1, DO1) on oxide surfaces has been studied by resonance Raman (RR) spectroscopy. The neutral and protonated forms of these molecules were modelled by ab initio calculations at the B3-LYP/DZ level, enabling calculation of the vibrational spectra of these species, together with vibrational assignments. Adsorption of PADA on silica-alumina and both PADA and DO1 on H-mordenite results in protonation, indicating the presence of Bronsted acidic sites on these oxide surfaces with pKa values ≤1.5. RR studies of the adsorption of PADA and DO1 can provide useful information regarding the nature of surface acidity on oxides which is complementary to that obtained from other probe molecules.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::4a75399bbb3f7d8e81a42fb6b50938a4 https://doi.org/10.1039/b407075e Zobrazit plný text záznamu