An easy and direct synthetic route to phosphamido niobocenes through nucleophilic attack of phosphide niobocene complexes on acyl halides

The synthesis of the new cationic functionalized phosphane niobocene complexes Nb(η⁵-C₅H₄SiMe₃)₂(P(CH₂CO(C₆H₅))Ph₂)(L)]Cl, LCO (3) or CNXylyl (4), and new phosphamido-niobocene complexes Nb(η⁵-C₅H₄SiMe₃)₂(P{CO(C₆H₅)}Ph₂)(L)]Cl, LCO (5), CNXylyl (6), Nb(η⁵-C₅H₄SiMe₃)₂(P(COCH(C₆H₅)₂)Ph₂)(L)]Cl, LCO (7) or CNXylyl (8), has been achieved. The complexes were prepared by reaction of the Lewis base niobocene complexes Nb(η⁵-C₅H₄SiMe₃)₂(PPh₂)(L)], LCO (1) or CNXylyl (2), with the appropriate RX (PhCOCH₂Cl, chloroacetophenone) and RCOX (PhCOCl, benzoyl chloride, Ph₂CHCOCl, diphenylacetyl chloride) reagents through the formation of new P–C bonds in the corresponding nucleophilic substitution reactions. These processes afforded new metallophosphanes in which one of the substituents on the phosphorus atom contains a ketonic moiety. The presence of the carbonyl group in the coordination sphere of phosphorus increases the coordination possibilities of the phosphane and enriches the applications of these complexes.