Bifunctional N–P ligands as building blocks for construction of multilayered metallodendrimers

The synthesis of 4-amino(N-methylendiphenylphosphino)pyridine (1a) and its reaction with [PdCl2(cod)], [PtCl2(cod)], [AuCl(tht)], [RuCl2(p-cymene)]2, [RhCl(cod)]2 and [Pd(η3-2-MeC3H4)Cl]2 to give [PdCl2(1a)2] (2), [PtCl2(1a)2] (3), [AuCl(1a)] (4), [RuCl2(p-cymene)(1a)] (5), [RhCl(cod)(1a)] (6) and [Pd(η3-2-MeC3H4)Cl(1a)] (7) respectively are described. The new chelate complex [Pd(η3-2-MeC3H4)(py–N(CH2–PPh2)2)](OTf) (8) is also reported. Compounds 5 and 8 were characterized by single crystal X-ray diffraction. In all complexes prepared the metal atoms appear to be bonded through the P atom of 1a. The metalloligands 4, 5 and 8 have been reacted with the ruthenocarbosilanedendrimer 10 to afford new Ru–Au and Ru–Pd concentric metal layered dendrimers 11, 12 and 13.

Graphical abstractCarbosilane dendrimers exhibiting two different metal layers are obtained using the bifunctional N–P ligand as connector.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of the ditopic ligand 4-amino(N-methylendiphenylphosphino)pyridine (1a). ► Metal coordination to 1a ligand through the phosphorous atom. ► X-ray studies of [RuCl2(p-cymene)(1a)] and [Pd(η3-2-MeC3H4)(py–N(CH2PPh2)2)](OTf). ► Synthesis of concentric metal layered dendrimers of Ru–Au and Ru–Pd.