A study of lone-pair interactions of tetracyclic diamines by ultraviolet photoelectron spectroscopy

Abstract

The ultraviolet photoelectron spectra of 2,7-diazatetracyclo[3.3.3.0.4,90.8,11]undecane (1) and its N,N-dimethyl- and methylene-bridged analogues 2 and 3 are documented. The spectrum of 2, which exhibits a nitrogen lone-pair splitting of 0.95 ± 0.1 eV, is interpreted on the basis of an interaction of "inside" lone pairs of the 1,2-diamine. Apparently this is the first report of a study of such an interaction. The spectrum of 1 is consistent with our view that 1 is an intramolecularly hydrogen bonded species in which the lone pairs are "inside–outside".