A statistical physics study of the interaction of [7]-helicene with alkali cations (K+ and Cs+): new insights on microscopic adsorption behavior. Issue 71 (19th September 2017)

• Record Type: Journal Article
• Authors: Ben Yahia, Mohamed; Tounsi, Moncef; Aouaini, Fatma; Knani, Salah; Ben Yahia, Manel; Ben Lamine, Abdelmottaleb
• Is Part Of: RSC advances. Volume 7:Issue 71(2017)
• Page Start: 44712
• Page End: 44723
• Publication Date: 2017-09-19
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7ra08387d
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : The adsorption of a metal ion to a polycyclic aromatic molecule such as helicene is the object of our study. Abstract : The adsorption of a metal ion to a polycyclic aromatic molecule such as helicene is the object of our study. The latter could function as a chiral molecular clamp for the cationic alkali metal. The main contribution of this work is to attribute new microscopic interpretations for the adsorption of potassium and cesium ions onto a thin layer of helicene achieved by the QCM technique. Throughout the grand canonical ensemble and some theoretical considerations, statistical physics processing has been used for modeling of experimental adsorption isotherms. A new model has been developed and chosen as an appropriate one to present a good correlation with experimental isotherms. Six physico-chemical parameters are obtained from the fitting of the experimental adsorption isotherms. Thanks to the steric parameters, we have found that an increase in temperature promotes a rise in the numbers of ions per site n 1 and n 2 and raises the adsorption capacities N M1 and N M2 . The two energetic parameters c 1 and c 2 allow deduction of the adsorption energies at four temperatures. It is found from the calculated energies that physical adsorption takes place; the helicene can function as potassium and cesium captor and the K + –helicene complex is more stable than the Cs + –helicene complex.