✍ Scribed by Corinne Payrastre; Yves Madaule; Jean Gérard Wolf; Tag Chong Kim; Marie-Rose Mazières; Robert Wolf; Michel Sanchez
No coin nor oath required. For personal study only.
In the grotz'ing field of dicoordinated Group 15 cations, the quantitative study of the Lewis acid properties of phosphenium or arsenium cations has not yet been undertaken. Moreover, there are only a few described examples of syntheses of arsenium cations. The aim of'this work is to enhance this series and to develop a quantitative comparative study of their complexation with Lewis bases such as pyridine. The obsewatioii ofthe I T NMR C-4 variation in the pyridine ring is a good probe to obtain the apparent equilibrium constant K, and thus a Lewis acidity scale. Phospheniiani cations are more acidic than arsenium cations.
' lbid AICIc .
📜 SIMILAR VOLUMES
## Abstract Rotational barriers and ^15^N chemical shifts have been measured in a number of ureas and thioureas. As anticipated on the basis of the ^15^N shifts, several previously unobserved rotational barriers could be detected by using lanthanide reagents or a high field spectrometer. Nearly con