Chromatographic characterisation of ordered mesoporous silicas. Part II: Acceptor-donor properties.

The ordered mesoporous siliceous materials: MCM41C16, MCM41C16-SH and MCM41C16-NH(2) (known as MCMs) having different surface functionalities were studied by inverse gas chromatography to characterise their acceptor-donor properties. The DN values denoting the donor number in the Gutmann scale and the AN* values denoting the acceptor number in the Riddle-Fowkes scale have been chosen in the estimation of the electron-acceptor parameter K(A) and electron-donor parameter K(D) values. The number and kind of the employed adsorbates have an influence on the results obtained. The problem of the number of adsorbates employed has been considered in the light of both results obtained in the present study and the data available in the literature for siliceous adsorbents with randomly ordered structures. Complementary information was obtained by X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy.