Analysis of phosphines functionalized with crown ether groups by NMR and cyclic voltammetry

The compound benzo-3,4-[18-crown-6]-diphenylphosphine was characterized by 31 P, 13 C and 1 H NMR in CDCl 3 and CD 3 CN and by cyclic voltammetry in CH 2 Cl 2 and CH 3 CN. The phosphine crown ether was found to be similar to triphenylphosphine in electrochemical and spectroscopic properties. Addition of M + PF 6 − (M + =Li + , Na + , or K + ) to the samples resulted in minimal changes in the observed 31 P spectra but significant differences in the electrochemistry. This suggests that binding a metal cation to the crown ether can be monitored electrochemically.