Preparation of phosphinoferrocene carboxamides from isocyanates. Synthesis and structural characterisation of palladium(II) and platinum(II) complexes with 1′-(diphenylphosphino)-1-(N-phenylcarbamoyl)ferrocene

The reaction of in situ generated 1′-(diphenylphosphino)-1-lithioferrocene with isocyanates RNCO affords the respective phosphino-carboxamides Ph2PfcCONHR (fc = ferrocene-1,1′-diyl, R = cyclohexyl (2), and Ph (3)) in moderate yields. The coordination behaviour of 3 chosen as a representative was studied in palladium(II) and platinum(II) complexes. Depending on the metal precursor and the reaction conditions, the following compounds featuring this ligand as a P-monodentate or an O,P-chelating donor were isolated and characterised by spectroscopic methods (IR, multinuclear NMR and electrospray ionisation MS): trans-[PdCl2(3-κP)2] (5), trans-[PtCl2(3-κP)2] (6), cis-[PtCl2(3-κP)2] (7), [SP-4-4]-[(LNC)PdCl(3-κP)] (8; LNC = 2-[(dimethylamino-κN)methyl]phenyl-κC1), and [SP-4-3]-[(LNC)PdCl(3-κ2O,P)]SbF6 (9). Besides, the crystal structures of a phosphine oxide resulting by oxidation of 2, viz Ph2P(O)fcCONHCy (4), and of complexes 5·2Et2O and 9 have been determined by single-crystal X-ray diffraction analysis.

In situ generated Ph2PfcLi (fc = ferrocene-1,1′-diyl) reacts with isocyanates RNCO (R = cyclohexyl or phenyl) to afford the corresponding carboxamides Ph2PfcCONHR. The series of Pd(II) and Pt(II) complexes prepared from Ph2PfcCONHPh, trans-[MCl2(L-κP)2] (M = Pd, Pt), cis-[PtCl2(L-κP)2], [(LNC)PdCl(L-κP)], and [(LNC)Pd(L-κ2O,P)]SbF6 (see figure), demonstrates the ability of the amidophosphines to coordinate as both the P-monodentate or O,P-chelating donors.Figure optionsDownload as PowerPoint slide