Thermal decomposition of cis-tetrahydropyridazine-3,4-d_2. Relative rates of rotation, cleavage, and closure for tetramethylene

The only 1,4 biradical described by theorists to date is tetramethylene. Despite the fact that substantial experimental work now exists on 1,4-biradical behavior, the relative rates of rotation, cleavage, and closure of the parent system are unknown. Substituted tetrahydropyridazines have been shown to be excellent sources for the thermal generation of stereospecifically labeled 1,4 bi radicals. Application of this method to the tetramethylene problem provides an opportunity for the direct comparison of experiment and theory