1H nuclear magnetic resonance study of 1,10-phenanthroline in aqueous acid. Isolation of bis(phenanthroline)–perchloric acid
Abstract
The 1H n.m.r. spectrum of 1,10-phenanthroline in aqueous acid has been examined as a function of acid concentration. Changes in the spectrum are consistent with the existence of three forms of protonated phenanthroline. At the highest acid concentrations (12M-HCl), diprotonated phenathroline (phenH22+) is the dominant species. When the formal concentration of acid equals that of phenanthroline, phenanthrolinium ion (phenH+) is present and can be precipitated with perchlorate ion. Further reduction of acidity gives phen2H+, which has been isolated as a perchlorate salt.