Synthesis, Characterizations, and Intramolecular Quenching Behavior of an Axially-Linked Trinuclear Molecular Wire Containing Ruthenium(II) Porphycenes

A new trinuclear complex <TEX>[Ru(TPrPc)(CO)]₂[Ru(pytpy)₂](PF₆)₂</TEX> (TPrPc = 2,7,12,17-tetra-n-propylporphycenato dianion and pytpy = 4'-(4-pyridyl)-2,2':6',2"-terpyridine) has been synthesized and characterized as the first example of a discrete molecular wire containing metalloporohycenes as a building block. The trinuclear complex shows multiple-step redox behavior in 0.1 M n-<TEX>Bu₄NPF₆</TEX>-dichloromethane. The mononuclear <TEX>[Ru(pytpy)₂]²⁺</TEX> precursor shows emission at 640 nm (deaerated acetone, 298 K) upon illumination at the metal-to-ligand charge transfer (MLCT) band at 495 nm, but the trinuclear molecular wire is found to be non-emissive upon photoexcitation at the central <TEX>[Ru(pytpy)₂]²⁺</TEX> entity, indicating an efficient quenching ability of the axially-linked, ruthenium(II)-porphycene chromophores in an intramolecular fashion.