Pyridinolyses of Phenyl Substituted Phenyl Tiocyanophosphate in Aetonitrile

초록

The kinetics and mechanism of the reactions of phenyl substituted phenyl thiocyanophosphate. With pyridines are investigated in acetonitrile at 55→. In case of more basic pyridines the magnitudes of ┭x indicate that mevhanism changes from a concerted process (┭x = 2.48~1.62) for the strongly basic substrate (Y = ┭-OCH3 ~ H) to a stepwise one with rate limiting formation of a trigonal bipyramidal penta-coordinated (TBP-5C) intermediate (┭y = -4.12 ~ ?2.47) for the less basic substrate (Y = H ~ ┭-Cl). This proposal is supported by a large negative cross-interaction constant (┭xy=-1.24) for the former and positive ┭xy (+4.21) for the later processes.