- 1,2-bis(diphenylphosphino)ethane: 1H (200 MHz, CDCl3, SiMe4,
            293 K). 31P{1H} (161 MHz, CDCl3, PO(OMe)3,
            293 K).
 
      - 1,2-bis[bis(pentafluorophenyl)phosphino]ethane. 31P{1H} (161
            MHz, CDCl3, PO(OMe)3, 293 K).
 
      - triphenylphosphine: 1H (200
            MHz, CDCl3, SiMe4, 293 K).