Low-temperature13C NMR investigations on carbon monoxide hydrogen bonded to Brønsted acid sites in HY zeolites

✍ Scribed by M. Koch; E. Brunner; H. Pfeifer; D. Zscherpel

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 376 KB
• Volume: 228
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(94)00994-5

✦ Synopsis

AlPStract

t3C NMR investigations were carried out at 4.5 K in order to analyze the lineshape of the solid-state spectrum of %O adsorbed on Bronsted acid sites in H-Y zeolites. The spectrum was found to be dominated by the chemical shift anisotropy and by the heteronuclear magnetic dipolar interaction between the t3C nucleus of the t3C0 molecule and the proton of the Bronsted acid site where the molecule is adsorbed. Therefore, an analysis of the lineshape of the low-temperature 13C NMR spectrum allows a precise determination of the hydrogen bond distance r H_c between these nuclei. A value of ru_c = 0.2 1 k 0.0 1 nm has been obtained by this method which is in excellent agreement with recent quantum chemical calculations.