Luminescent ionic heterobimetallic diphosphine-β-diketiminate complexes

The syntheses of luminescent heterobimetallic ionic complexes based on the bis(phosphine)-functionalized β-diketiminate ligand [HC{(CH$_3$)C}$_2$ {(o-[P(C$_6$ H$_5$)$_2$]$_2$C$_6$ H$_4$ )N}$_2$]$^-$ (PNac) are reported. This orthogonal ligand is characterized by its PNNP pocket, which contains both hard and soft donor sites and therefore enables the selective coordination of two different metal ions in spatial proximity, significantly changing the photoluminescent properties. Salt elimination reaction of [PNacK] with zinc chloride yields the mono-metallic complex [PNacZnCl], in which the zinc ion is square-pyramidally coordinated within the PNNP pocket. The introduction of the coinage metal ions Au$^I$ , Ag$^I$and Cu$^I$ into the PNNP pocket as a second metal ion is achieved by simple complexation reactions using their corresponding weakly coordinating anion (WCA) salts. In the resulting ionic heterobimetallic complexes [PNacZnCl(thf)M]$^+$ (M = Au, Ag, and Cu), the coinage metal ions are linearly coordinated by the two phosphine units, while the zinc ion is tetra-hedrally coordinated at the diketiminate unit. The photoluminescent properties are significantly altered by the spatial proximity of the two metal ions. ... mehrFurthermore, the ionic gold–copper complex [PNacAuCu(MeCN)]$^+$ was isolated by introducing Cu$^I$ into the monometallic gold complex using the same method.