The nature of the system (π-C 4H 7PdCl) 2-electron donor from 1H, 13C and 13P NMR spectroscopic and electrodialysis studies : II. (π-C 4H 7PdCl) 2-triphenylphosphine

Abstract

A study has been made of the reactions (π-C 4H 7PdCl) 2[ = M 2] and PPh 3[= L] in a CDCl 3 solution. In the presence of excess M 2, the complex C 4H 7PdCl☆PPh 3 was obtained, the initial formation of the complex being readily observed in both the 1H and 13C NMR spectra. At temperatures above 40°, the signals of both complexes became averaged in the 13C NMR spectra. In the presence of excess phosphine (up to the ratio PPh 3/Pd2), exchange reactions involving free and complexed PPh 3 took place. The kinetics of the system has been studied using 31P NMR spectra. The intermediates formed were shown to be ML 2 and ML 3 which decomposed to give ML and L and also dissociate into ions. The nature of the ions present was established by electrodialysis studies of the system ( 14C 4H 7Pd 36Cl) 2 + PPh 3. It was found that low temperatures and concentrations gave predominantly Cl − and C 4H 7Pd·L + 3 ions, whilst high temperatures and concentrations led to the formation of C 4H − 7 and PdCl☆L + 3 ions. The data on electrical conductivity and electrodialysis have been compared qualitatively with the 13C NMR spectra.