Even though my mass and single crystal data are correct, why am I getting excess PPh3 peak in the 31P NMR? Can someone let me know?

I have got mass and single crystal data for Pd(II)triphenyl phosphine complex. But I am still getting a peak at -4 ppm in the 31P NMR. I have given enough hexane wash to remove excess PPh3.

16 September 2021 2,890 4 View