Heterochiral vs. Homochiral Linkage of Emissive Iridium(III) Complexes with D-Penicillaminate: Drastic Change in Emission Induced by Silver(I) Linkage

Reactions of [{Ir(ppy or ppy‐CF3)2}2(μ‐Cl)2] {Hppy = 2‐phenylpyridine, Hppy‐CF3 = 2‐[3,5‐bis(trifluoromethyl)phenyl]pyridine} with D‐penicillamine (D‐H2pen) afforded emissive IrIII mononuclear complexes [Ir(ppy or ppy‐CF3)2(D‐Hpen‐N,S)] as a 1:1 mixture of the ΔD/ΛD isomers. These complexes were converted into IrIIIAgIIrIII trinuclear structures in [Ag{Ir(D‐pen‐N,S)(ppy or ppy‐CF3)2}{Ir(D‐Hpen‐N,S)(ppy or ppy‐CF3)2}] by treatment with AgNO3, which led to a drastic blueshift of the emission bands. Whereas the (ppy)IrIIIAgIIrIII complex produced the heterochiral ΔDΛD isomer, the ppy‐CF3 complex gave the homochiral ΔDΔD and ΛDΛD isomers that could completely be separated by crystallization. It was found that the quantum efficiency of the emission band for the ΔDΔD isomer is much lower than that for the ΛDΛD isomer. Emissive IrIII complexes [Ir(D‐Hpen)(ppy or ppy‐CF3)2] were converted into IrIIIAgIIrIII complexes by linking with AgI, which led to a drastic blueshift of the emission bands. Whereas the (ppy)IrIIIAgIIrIII complex produced only the ΔDΛD isomer, the ppy‐CF3 complex gave the ΔDΔD andΛDΛD isomers that could completely be separated by crystallization. The emission quantum efficiencies for the ΔDΔD and ΛDΛD isomers were found to be markedly different, indicative of the importance of chirality in the control of emission properties.