Synthesizing Multidentate Ferrocenylphosphines: A Powerful Route to Dissymmetrically Tri-Substituted Ferrocenes. X-ray Structure and 13C NMR of a Diaryl–Alkyl-phosphino Ferrocene

As a powerful route to multidentate ferrocenylphosphines, the synthetic strategy which consists in successively reacting FeCl2 with the suitably substituted cyclopentadienyllithium salts was carried out. The new mixed diaryl/alkyl triphosphine 1,2-bis(diphenylphosphino)-1′-(diisopropylphosphino)-4-tert-butylferrocene, Fc(P)2tBu(PiPr), was obtained in good yield (70%). A very rare through-space nuclear spin–spin coupling JCP = 5.5 Hz was evidenced from its reported 13C NMR and X-ray molecular structure characterizations.