Two-dimensional 31P Exchange NMR Study of Adsorbed Phosphine Layers

Autor:	Ian D. Gay, Bing Hu, Tai-Cheng Sheng
Rok vydání:	1999
Předmět:	Chemistry Chemical exchange Inorganic chemistry Surfaces and Interfaces Condensed Matter Physics Ion chemistry.chemical_compound Adsorption Reaction rate constant Electrochemistry General Materials Science Phosphonium Spectroscopy Phosphine
Zdroj:	Langmuir. 15:6132-6134
ISSN:	1520-5827 0743-7463
Popis:	Adsorption of organic phosphines on acidic surfaces produces phosphonium ions, which can be detected by 31P NMR, since their chemical shift is different from that of the free phosphine. In the presence of excess adsorbed phosphine, lines from both phosphine and phosphonium are observed. Two-dimensional exchange NMR is applied to trimethyl- and triphenylphosphines adsorbed on SiO2−Al2O3 and demonstrates that free phosphine and phosphonium ions are undergoing chemical exchange at ambient temperatures. There are two populations of PMe3H+ which exchange with different rate constants, 7 × 104 and 800 s-1, respectively. PPh3H+ exchanges much more slowly with PPh3, having a rate constant of 14 s-1.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::751f1e8e47dc947a232dea8904f7b945 https://doi.org/10.1021/la990302i Zobrazit plný text záznamu