Neopentyl- and trimethylsilylmethylpalladium chemistry: synthesis of reagents for organopalladium chemistry and the crystal structure of the neopentyl(phenyl)palladium(IV) complex [Pd(mq)(CH2CMe3)Ph(bpy)]Br (mq=8-methylquinolinyl, bpy=2,2′-bipyridine)

Synthetic routes to neopentyl and trimethylsilylmethyl complexes of Pd(II) are reported, Pd(CH2EMe3)Ph(tmeda) [E=C (1), Si (3); tmeda=N,N,N′,N′-tetramethylethylenediamine] and Pd(CH2EMe3)Ph(bpy) [E=C (2), Si (4); bpy=2,2′-bipyridine]. Complexes 1 and 3 are formed on the reaction of PdIPh(tmeda) with LiCH2EMe3, and they react with bpy to give 2 and 4. Oxidative addition reactions of 8-(bromomethyl)quinoline (mqBr) with Pd(CH2EMe3)Ph(bpy) result in the formation of octahedral Pd(IV) complexes [Pd(mq)(CH2EMe3)Ph(bpy)]Br [E=C (5), Si (6)]. An X-ray structural analysis for 5, the first example of a stable cationic arylpalladium(IV) complex, shows a fac-PdC3N3 configuration with the neopentyl group trans to the quinoline nitrogen donor atom.