Ab initio study of cyclobutadiene and its aza-substituted derivatives. Ground state properties and vibrational frequencies

Ab initio calculations at the doubly-excited configuration interaction (CID) level of approximation are presented for cyclobutadiene and its aza-substituted derivatives. The geometries of all the compounds were fully optimized and the vibrational frequencies calculated. The isomerization barrier was calculated for tetraazacyclobutadiene and it is found to be much larger than in cyclobutadiene; therefore it is unlikely that this compound would exhibit tunneling isomerization as cyclobutadiene. The calculated π bond orders of these compounds indicate that all of them exhibit antiaromatic characteristics similar to those of cyclobutadiene. © 1991.

Duke Scholars

Author Julio Cesar Facelli Biostatistics & Bioinformatics, Division of Translational Bi ...