A Coordination-Induced 1,4→1,2-Quinonediimine Isomerization.

Hitherto unused in coordination compounds, the para-quinonoid azophenine (p-ap) has now been applied for the synthesis of [Cu(PPh ) (o-ap)](BF ) (1), in which the ligand exists as its ortho-quinonoid tautomer. Additional stabilization of this metal-π donor/ligand-π acceptor arrangement occurs through chelate-like hydrogen bonding between the NH functionalities, which are both now ortho-positioned, and the BF counterion.

CpIr(dab) (dab = 1,4-Bis(2,6-dimethylphenyl)-1,4-diazabutadiene): A Coordinatively Unsaturated Six-pi-Electron Metallaheteroaromatic Compound?

1,4-Bis(2,6-dimethylphenyl)-1,4-diaza-1,3-butadiene (dab) forms the structurally characterized iridium(III) complex [CpIrCl(dab)](PF(6)): C(28)H(35)ClF(6)IrN(2)P, orthorhombic, space group Pnma, a = 16.187(2) Å, b = 15.823(2) Å, c = 11.