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)

• The title allyl Pd(II) complex has been obtained from [(COD)Pd(Me)Cl], the N^N and Ag+ ions in a one-pot reaction.
• XRD, detailed NMR and MS show the structural entity of the cationic complex.
• A mechanism for the formation of the anionic (η3-6-methyl-cyclooct-2-en-1-id) (allyl) coligand is presented.
• The role of the bulky 2,3-dimethyl-1,4-bis(2,6-dimethylphenyl)-diazabuta-1,3-diene ligand is discussed.

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.

The unique allyl Pd(II) complex [(Me2-Xyl-DAB)Pd(η3-6-methyl-cyclooct-2-en-1-id)]+ containing the bulky N^N Me2-Xyl-DAB (2,3-dimethyl-N,N′-bis(2,6-dimethylphenyl)-diazabuta-1,3-dien) has been formed in an interesting sequence of organometallic reactions starting from [(COD)Pd(Me)Cl], Ag[SbF6] and the N^N.Figure optionsDownload as PowerPoint slide