Preparation and reactions of 2-pyridylplatinum(II) complexes 2)(L)2> (L = tertiary phosphine). Compounds with a markedly nucleophilic pyridine nitrogen atom.

Article abstract of DOI:10.1016/0022-328X(89)85390-2

The 2-pyridyl complex trans-2)(PPh3)2> (I) can be prepared in high yield by oxidative addition of 2-chloropyridine to .The reaction of I with 1,2-bis(diphenylphosphino)ethane yields the cis derivative 2)(dppe)> (II).In polar solvents, the latter rearranges to the binuclear cationic complex 2,N)(dppe)>2Cl2.The reaction of I with 3-2-MeC3H4)>2 (1/0.5 molar ratio) gives the products 2,N)(PPh3)>2 (IV) and 3-2-MeC3H4)(PPh3)>. 31P NMR monitoring of the reaction suggests that PPh3 transfer occurs in a binuclear platinum/palladium intermediate with a bridging 2-pyridyl ligand, and leads initially to a chloride-bridged species 2)(PPh3)>2, which then rearranges to the more stable compound IV.Complexes I and II are readly N-protonated by HCl or HClO4 to give the cationic derivatives 2)(PPh3)2>⁺ and 2)(dppe)>⁺.In dichloromethane or 1,2-dichloroethane the terminal 2-pyridyl group of I and II is slowly N-alkylated by the solvent to give 2>(PPh3)2>Cl and 2>(dppe)>Cl (R = CH2Cl or CH2CH2Cl).