Experimental and computational studies of the structure and vibrational spectra of azetidine derivatives

The IR spectra of 3,3-dinitroazetidine (DNAZ), 1-nitroso-3,3-dinitroazetidi ne (nitroso-DNAZ), and azetidine in solid argon matrices were measured. In addition, the structures and harmonic vibrational frequencies of these mole cules were theoretically evaluated using three electronic structure methods : restricted Hartree-Fock and the B3LYP and BP86 density functional methods . The computed geometries are compared with the experimental measurements. The computed vibrational frequencies are used to determine the types of mol ecular motion associated with each of the observed experimental bands. Comp arison with the experimental spectra provides important information about t he ability of these computational methods to describe the vibrational modes in these highly polar strained ring compounds. (C) 1999 Elsevier Science B .V. All rights reserved.