A ruthenium(ii) complex-cyanine energy transfer scaffold based luminescence probe for ratiometric detection and imaging of mitochondrial peroxynitrite.

A novel ruthenium(ii) complex-cyanine energy transfer scaffold has been established for the development of a ratiometric luminescence probe for ONOO- detection. The probe, Ru-Cy5, is localized in mitochondria of live cells, allowing ratiometric sensing and imaging of ONOO- therein.

Development of a Novel Lysosome-Targeted Ruthenium(II) Complex for Phosphorescence/Time-Gated Luminescence Assay of Biothiols.

Considering the important roles of biothiols in lysosomes of live organisms, and unique photophysical/photochemical properties of ruthenium(II) complexes, a novel ruthenium(II) complex, Ru-2, has been developed as a molecular probe for phosphorescence and time-gated luminescence assay of biothiols in human sera, live cells, and in vivo. Ru-2 is weakly luminescent due to the effective photoinduced electron transfer (PET) from Ru(II) luminophore to electron acceptor, 2,4-dinitrobenzene-sulfonyl (DNBS). In the presence of biothiols, such as glutathione (GSH), cysteine (Cys), and homocysteine (Hcy), the emission of Ru-2 solution was switched ON, as a result of the cleavage of quencher to form the product, Ru-1.

A highly selective phosphorescence probe for histidine in living bodies.

In this work, we designed and synthesized a heterobimetallic ruthenium(ii)-nickel(ii) complex, [Ru(bpy)2(phen-DPA)Ni](PF6)4 (Ru-Ni), as a highly selective phosphorescence probe for histidine. The probe exhibited weak emission at 603 nm because the phosphorescence of the Ru(ii) complex can be strongly quenched by the paramagnetic Ni(2+) ion. In the presence of histidine, reaction of Ru-Ni with histidine resulted in the release of nickel(ii) and an enhancement in the phosphorescence intensity at 603 nm.

A functional ruthenium(ii) complex for imaging biothiols in living bodies.

A unique ruthenium(ii) complex, [Ru(bpy)2(DNS-bpy)](PF6)2 [bpy: 2,2'-bipyridine, DNS-bpy: 4-(2,4-dinitrophenylthio)-2,2'-bipyridine], that can act as a probe for the recognition and luminescence sensing of biothiols has been designed and synthesized. Due to the presence of effective photo-induced electron transfer (PET) from the potent electron donor (Ru-bpy centre) to the strong electron acceptor (2,4-dinitrophenyl moiety), the Ru(ii) complex itself is weakly luminescent. Reaction of [Ru(bpy)2(DNS-bpy)](PF6)2 with biothiols leads to the replacement of the 2,4-dinitrophenyl moiety by biothiols, which results in the loss of PET within the complex, to allow recovery of the MLCT-based emission of the Ru(ii) complex with an 80-fold increase in luminescence intensity.