Knowledge Bank

The ring-puckering data on cyclobutane and cyclobutane-$d8$ have been reexamined including the coordinate dependence of the reduced mass in the Hamiltonian. The implications of slight differences in the form of the ring-puckering coordinate for the two isotopic species on the determination of barrier heights and dihedral angles will be considered. The pitfalls of “determining” small differences in barrier heights among isotopic species will be discussed. This research was supported by the Petroleum Research Fund, American Chemical Society and by the Biological and Physical Science Research Institute, Mississippi State University.