Two-Photon-Triggered NO Release via a Ruthenium–Nitrosyl Complex with a Star-Shaped Architecture

We report herein a molecular engineering strategy based on the design of a multipolar ruthenium–nitrosyl (Ru–NO) complex with a three-branched architecture. The three Ru–NO units are introduced at the periphery of a highly π-delocalized truxene core bearing three terpyridine ligands. The two-photon absorption capabilities of the complex were investigated by the Z-scan technique. The strong electronic coupling among the individual arms gives rise to a very strong two-photon absorption response (δ_800 nm ∼ 1600 GM), which corresponds to a 16-fold enhancement of the capability of a single-arm reference, thereby promoting an efficient light-driven NO release process in aqueous media.