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Tuning the aryl substituents of N,N′-diaryl-2,3-dimethyl-1,4-diaza-1,3-butadiene (DAB) ligands promotes the challenging C–C bond-forming reductive elimination from PtIV diimine complexes [(DAB)Pt(CH3)3(solvent)]+ (2) under mild conditions. Experimental results and density functional calculations indicate that 2,6-aryl substitution promotes reductive elimination by facilitating dissociation of the coordinating solvent by close to 10 kcal mol–1, but too much steric bulk inhibits the formation of 2 in the one-electron outersphere oxidation of (DAB)Pt(CH3)2 (1).

The disproportionation of 2 equiv of (L)2Pd(CH3)(X) to form 1 equiv of (L)2Pd(CH3)2 and 1 equiv of (L)2Pd(X)2 could serve as a key step in the catalytic oxidative oligomerization of methane. The thermodynamics associated with this transformation have been evaluated as a function of the supporting ligands L and X using DFT calculations. With these calculations as a guide, we demonstrate the first experimental example of disproportionation of a PdII monomethyl complex to generate a PdII dimethyl species using (tBu-bpy)Pd(CH3)(CH2COCH3) (tBu-bpy = 4,4′-di-tert-butyl-2,2′-bipyridine) as the starting material.

Palladium(II) complexes containing bidentate cyclometalated C∼N chelating ligands are shown to react with PhINTs at room temperature to insert “NTs” into the Pd−C bond. This “NTs” insertion reaction has been applied to palladacyclic complexes of azobenzene, benzo[h]quinoline, and 8-ethylquinoline. The newly aminated organic ligands can be liberated from the metal center by protonolysis with trifluoroacetic acid or HCl.