Dimethylaluminium iminophosphoranylenamides and iminophosphoranylanilides: Synthesis, characterisation, and their controlled ring-opening polymerisation of ε-caprolactone

Abstract

A series of aluminium iminophosphoranylenamide complexes, [Me₂Al{N(Ar)C(Ph)CHP(Ph₂)N-Ar¹}] (Ar = Ph, Ar¹ = p-MeC₆H₄ (9); Ar = Ph, Ar¹ = o-ClC₆H₄ (10); Ar = Ph, Ar¹ = o-FC₆H₄ (11); Ar = p-MeC₆H₄, Ar¹ = o-FC₆H₄ (12)), were synthesised by the reactions of ArNC(Ph)CH₂P(Ph₂)NAr¹ (5–8) with AlMe₃ in toluene. Similar reactions between o-{ArNP(Ph₂)}C₆H₄NHC(Ph)CHP(Ph₂)NAr (Ar = p-MeC₆H₄, 13), and AlMe₃ in toluene generates aluminium iminophosphoranylanilide, 14. All new compounds were characterised by NMR spectroscopy and elemental analysis. The molecular structures of complexes 9 and 14 were further characterised by single-crystal X-ray structure determination. In the presence of benzyl alcohol (BnOH) each of the complexes is catalytically active for the ring-opening polymerisation (ROP) of ε-caprolactone (ε-CL), and complex 14 has the highest activity among them.