Knowledge Bank

The microwave spectrum of l-methyl cyclobutene was studied in order to compare the barrier of this compound with those of propylene (2000 cal. $mole-1$) and l-methyl cyclopropene (1390). The barrier was found to be $(1640\pm 30)$ cal. $mole-1$ as determined by the splitting of the ground and the first torsional state transitions. Dipole moments have also been measured. The final results are: [FIGURE] $\mu A=0.32\pm 0.0D,\mu B=0.16\pm 0.02,\mu =0.36\pm 0.02.$ The higher vibrational states are being studied to determine $V\ast \ast \ast$.