Pyridinium Ions - New Probe for Basic Sites of Solid Acids

Autor:	Jan Florián, Josef Kotrla, Ludmila Kubelková, J. Fraissard
Rok vydání:	1995
Předmět:	chemistry.chemical_compound Crystallography Deprotonation chemistry Hydrogen bond Ab initio quantum chemistry methods Inorganic chemistry Pyridine General Chemistry Pyridinium Fourier transform infrared spectroscopy Zeolite Pyrrole
Zdroj:	Collection of Czechoslovak Chemical Communications. 60:393-402
ISSN:	1212-6950 0010-0765
DOI:	10.1135/cccc19950393
Popis:	The hydrogen bonding interactions of the pyridinium ion (PyH+) with the deprotonated skeleton of acid zeolites were studied using Fourier transform infrared (FTIR) spectroscopy and quantum chemical ab initio calculations. It was found that the frequency of the NH stretching vibration, n(NH), of the newly formed H-bond increases in the zeolite sequence HNaX < HY < HM ~ HZSM-5. This is related to decreasing basicity of the skeletal oxygens (basic sites conjugated to bridging hydroxyls). Therefore, pyridine can serve as a probe for the basic sites of acid zeolites. In this way it can complement the pyrrole probe, which is established for basicity monitoring of alkali-metal exchanged zeolites.
Databáze:	OpenAIRE
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