507271-10-5Relevant academic research and scientific papers
Metallation of unactivated methyl groups - Platinum (II) derivatives with 6-alkyl-2,2′-bipyridines
Zucca, Antonio,Stoccoro, Sergio,Cinellu, Maria Agostina,Minghetti, Giovanni,Manassero, Mario,Sansoni, Mirella
, p. 3336 - 3346 (2007/10/03)
The reaction of K2[PtCl4] with three 6-alkyl-2,2′-bipyridines HL, (N2C10H7R; R = CH2Me, HLet; CHMe2, HLip; CH2CMe3, HLnp) affords five- and six-membered cyclometallated complexes [Pt(L)Cl] where L is a terdentate N,N,C anionic ligand which originates from HL through direct activation of a C(sp3)-H bond. In the case of HLip, metallation generates a stereogenic carbon atom β to the metal. Complex 5, [Pt(Lnp)Cl], having an uncommon six-membered ring containing a Pt-C(sp3) bond, was studied in depth in solution, by means of 1- and 2- dimensional NMR spectroscopy, and in the solid state by X-ray diffraction. Differences are observed in the behaviour of these ligands: thus with HLet an adduct, [Pt(HLet)Cl2], was also isolated and its structure was determined by X-ray diffraction. In the metallated species, the fourth ligand, Cl, can easily be substituted by neutral or anionic ligands (CO, PPh3, CN-). The metallated species react with potentially bidentate ligands L′-L″ [Ph2PCH2PPh2 (dppm), Ph2P(CH2)2PPh2 (dppe), Ph2P(CH2)2AsPh2 (dppae)] to give, with different Pt:L ratios, mononuclear [Pt(L)(L′-L″)]+ or dinuclear [(L)Pt(μ-L′-L″)Pt(L)]++ cationic species. In the second case an uncommon unsupported L′-L″ bridge is present. The cyclometallated species are stable in air and moisture, and the N,N,C system is rather robust. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
