Unexpected formation of [(Me2-Xyl-DAB)Pd(η3-6-methyloct-2-en-1-id)][SbF6] (Me2-Xyl-DAB = 2,3-dimethyl-1,4-bis(2,6-dimethylphenyl)-diazabuta-1,3-diene)

Reaction of [(COD)Pd(Me)Cl] with Ag[SbF6] and 1.5 eq of the N^N Me2-Xyl-DAB (2,3-dimethyl-N,N′-bis(2,6-dimethylphenyl)-diazabuta-1,3-dien) afforded the title complex [(Me2-Xyl-DAB)Pd(η3-6-methyl-cyclooct-2-en-1-id)][SbF6]. From a single crystal XRD study, 1H NMR and MS it is clear, that the compound contains a cationic Pd(II) complex with a neutral diaza-butadiene chelate ligand and an anionic, thus allylic, η3-6-methyl-cyclooct-2-en-1-id coligand. Presumably, the cationic complex has been formed by methylation of one of the olefin groups of the coordinated COD ligand. Details of this very interesting reaction were discussed in view of much related observations.