Activation energies and formation rate constants for organic arsenical-antidote adducts as determined by dynamic NMR spectroscopy.

Phenyldichloroarsine reacts with 1,3-dimercapto-2-propanol and 1,2-dimercaptopropane to form 1:1 adducts in the form of a six-membered and five-membered heteroatom rings. Two geometric isomers for each compound are present in dynamic equilibrium. Rate constants and the activation barriers for the interconversion of the geometric isomers were determined by dynamic NMR spectroscopy. The activation barriers indicate that the five-membered heteroatom ring is more stable than the six-membered heteroatom ring.