1,2-Disubstituted Aryl-Based Ferrocenyl Phosphines

Ferrocenylaryl- or ferrocenylheteroarylphosphines [Fe­{1-PPh₂(spacer)-2-NMe₂CH₂C₅H₃}­(C₅H₅)] (spacer = 1,4-phenylene (rac-6), 1,3-phenylene (rac-7), 4,4′-biphenylene (rac-8), 2,5-thienylene (rac-9)) were prepared in a facile two-step sequence starting with Negishi cross-coupling between N,N-dimethylaminomethylferrocene and aryl halide phosphine oxides, Br-spacer-P­(O)­Ph₂, followed by reduction with trichlorosilane. All products were characterized spectroscopically (¹H, ¹³C, and ³¹P NMR, MS, FTIR), and rac-6, the corresponding phosphine oxide rac-2, and rac-9 were also characterized by X-ray crystallography. Furthermore, the redox properties of rac-2–9 were studied by cyclic voltammetry.