ChemInform Abstract: Evidence for Some Pentadentate Coordination in Ethylenediamine-N,N′-diacetato-N,N′-di-3-propionatonickelate(II).
Abstract
The 1H and 13C contact shifted NMR spectra of the title complex are reported as a function of temperature.
ChemInform Abstract
The 1H and 13C contact shifted NMR spectra of the title complex are reported as a function of temperature. The data indicate that the ligand acts as a hexadentate coordinator at least 98% of the time at room temp. with the six-membered propionate rings occupying the in-plane sites and the acetates occupying the out-of-plane sites. The amount of pentadentate form of the ligand increases at high temp., reaching 22% pentadentate at 100 °C. ΔH and ΔS for the hexadentate-pentadentate equilibrium are determined. The conversion involves removal of one of the out-of-plane acetates. No evidence for uncoordinated propionate is observed at any temperature.
