Bimetallic Ruthenium Nitrosyl Complexes with Enhanced Two‐Photon Absorption Properties for Nitric Oxide Delivery. Issue 62 (5th September 2022) - Juarez‐Martinez, Yael
Abstract: One monometallic and three bimetallic ruthenium nitrosyl (RuNO) complexes are presented and fully characterized in reference to a parent monometallic complex of formula [FTRu(bpy)(NO)] 3+, where FT is a fluorenyl‐substituted terpyridine ligand, and bpy the 2, 2'‐bipyridine. These new complexes are built with the new ligands FFT, TFT, TFFT, and TF‐CC‐TF (where an alkyne C≡C group is inserted between two fluorenes). The crystal structures of the bis‐RuNO2 and bis‐RuNO complexes built from the TFT ligand are presented. The evolution of the spectroscopic features (intensities and energies) along the series, at one‐photon absorption (OPA) correlates well with the TD‐DFT computations. A spectacular effect is observed at two‐photon absorption (TPA) with a large enhancement of the molecular cross‐section ( σ TPA ), in the bimetallic species. In the best case, σ TPA is equal to 1523±98 GM at 700 nm, in the therapeutic window of transparency of biological tissues. All compounds are capable of releasing NO⋅ under irradiation, which leads to promising applications in TPA‐based drug delivery. Abstract : Nitric oxide delivery : A series of bimetallic RuNO complexes with quadrupolar electronic structures exhibit TPA cross‐section up to 1523 GM under irradiation at λ =700 nm, in the therapeutic window of transparency of biological tissues. The biologically active nitric oxide radical (NO⋅) is released in any case.