Abstract Gas-phase He-I photoelectron spectra of N-tert-butyl-1, 2-dihydro [1, 3, 2] diazaborolo [1, 5-a] pyridine (3) and its thermolysis product, the parent compound 1, have been recorded and assessed by density functional theory calculations. Similarly, N-tert- butylisoindole (4) and the parent isoindole (2) were also studied. The first ionization energies of these compounds increase in the series 3 (6.75 eV)< 1 (6.85 eV)< 4 (6.9 eV)< ...
