Organoplatinum(IV) and palladium(IV) complexes containing intramolecular coordination systems based on the 8-methylquinolinyl group (mq), including structures of the cation [Pt(mq)Me2(pby)]+ (pby=2,2′-bipyridine) and the palladium(IV) complexes Pd(mq)MeR{(pz)2BH2} (R = Me, Ph;: [(pz)2BH2]- = bis(pyrazol-1-yl)borate)

Oxidative addition of 8-(bromomethyl)quinoline (mqBr) to PdMeR(bpy) (R Me, Ph; bpy = 2,2'-bipyridine) and [PdMeR{(pz)(2)BH2)](-) (R = Me, Ph; [(pz)(2)BH2](-) = bis(pyrazol-1-yl)boratel]) has given the first isolable palladium(IV) complexes containing an intramolecular coordination system, [Pd(mq)MeR(bpy)]Br ER = Me (1),Ph(2)1 and [Pd(mq)MeR((pz)(2)BH2)[R = Me (7), Ph (8)]. The pallada(IV)cyclic complex [Pd(CH2CH2CH2CH2)( mq)(bpy)]Br (g% has also been isolated. The first structural analysis of an arylpalladium(IV) complex, Pd-(mq))MePh(pz)(2)BH2) (8), is reported. Complex 8 occurs as two isomers and the one examined by X-ray crystallography has the fac-PdC3 configuration with the phenyl group trans to the quinoline nitrogen donor. NMR spectra of 8 indicate that the other isomer has the methyl group trans to the quinoline nitrogen donor. Similar geometric isomerism occurs for Pd-(mq)MePh(bpy)]BF4 (4). Structural studies of the dimethylpalladium(Iv) complex Pd(mq)Me-2{(pz)2BH2)} (7) and the platinum(IV) cation:in [Pd(mq)Me-2(bpy)]BF4 0.75(CH2Cl2) (5) reveal similar structures. The cation Pd(mq)Me-2(bpy)]+ is-less stable than the methyl(phenyl)palladium(IV) analogue (2), decomposing in (CD3)(2)CO by reductive elimination to form ethane and 8-ethylquinoline in similar to 1:2 ratio, together with the Pd(II) products [Pd(mq)(bpy)]Br and PdBrMe(bpy). A complex mixture of 8-substituted-quinolines (saturated and unsaturated substituents) were obtained as the major products of decomposition: of (Pd(CH2CH2CH2CH2)(mq)(bpy)]Br (6), consistent with mq CH2 coupling to give Pd(II) species that undergo further decomposition.