Mononuclear and dinuclear palladium and nickel complexes of phosphinimine-based tridentate ligands

Abstract

The tridentate bis-phosphinimine ligands O(1,2-C₆H₄NPPh₃)₂1, HN(1,2-C₂H₄NPR₃)₂ (R = Ph 2, iPr 3), MeN(1,2-C₂H₄NPPh₃)₂4 and HN(1,2-C₆H₄NPPh₃)₂5 were prepared. Employing these ligands, monometallic Pd and Ni complexes O(1,2-C₆H₄NPPh₃)₂PdCl₂6, RN(1,2-CH₂CH₂NPPh₃)₂PdCl][Cl] (R = H 7, Me 8), [HN(1,2-CH₂CH₂NPiPr₃)₂PdCl][Cl] 9, [MeN(1,2-CH₂CH₂NPPh₃)₂PdCl][PF₆] 10, [HN(1,2-CH₂CH₂NPPh₃)₂NiCl₂] 11, [HN(1,2-CH₂CH₂NPR₃)₂NiCl][X] (X = Cl, R = iPr 12, X = PF₆, R = Ph 13, iPr 14), and [HN(1,2-C₆H₄NPPh₃)₂Ni(MeCN)₂][BF₄]Cl 15 were prepared and characterized. While the ether-bis-phosphinimine ligand 1 acts in a bidentate fashion to Pd, the amine-bis-phosphinimine ligands 2–5 act in a tridentate fashion, yielding monometallic complexes of varying geometries. In contrast, initial reaction of the amine-bis-phosphinimine ligands with base followed by treatment with NiCl₂(DME), afforded the amide-bridged bimetallic complexes N(1,2-CH₂CH₂NPR₃)₂Ni₂Cl₃ (R = Ph 16, iPr 17) and N(1,2-C₆H₄NPPh₃)₂Ni₂Cl₃18. The precise nature of a number of these complexes were crystallographically characterized.