Exploring the Ability of Luminescent Metal Assemblies to Bind and Sense Anionic or Ionizable Analytes A Ru(phen)2bipy-Based Dizinc Complex for Bisphenol A (BPA) Recognition

Abstract

The synthesis of a new RuII complex, in which the metal is coordinated by two 1,10-phenanthroline ligands and a 2,2′-bipyridyl unit linked, via methylene bridges in its 4 and 4′ positions, to two 1,4,7,10-tetraazacyclododecane (cyclen) macrocycles ([Ru(phen)2L]2+) is reported. Protonation and ZnII binding by [Ru(phen)2L]2+ have been analyzed by potentiometric titration, evidencing the formation of mixed hetero-binuclear and hetero-trinuclear ZnII/RuII complexes. These complexes were tested as bis-phenol A (BPA) binders. Only the dizinc complex with [Ru(phen)2L]2+ is able to bind BPA in aqueous solution, affording a remarkably stable {Zn2[Ru(phen)2L]BPA(H−2)}4+ adduct at neutral pH, in which BPA is bound in its doubly deprotonated form to the two ZnII ions. BPA binding was found to quench the luminescence emission of the RuII(phen)2bipy core. Although the quenching effect is modest, this study demonstrates that appropriately designed dizinc complexes can be used for binding and optical sensing of BPA in water.

Ferritin nanocomposites for the selective delivery of photosensitizing ruthenium-polypyridyl compounds to cancer cells

“…S3 and S4 †). 8,34,35 As Ru1 and Ru2 are highly hydrophilic and stable even at pH 12, 31,33 they were incubated in the presence of HuHf during the disassembly process at different molar ratios fold with respect to the protein). In order to remove the excess of Ru1 or Ru2, i.e.…”

“…The synthesis of the polyamino macrocycles L′ and L″ are reported in previous works 33,48 while the corresponding ruthenium(II) complexes were prepared according to our previous papers. 31,33 Fig. 5 Cell internalization of Ru1@HuHf and Ru2@HuHf.…”

“…31,32 The presence of many easily protonatable nitrogen groups on the unique polyazamacrocyclic moiety of Ru1, or on the two distinct cyclen (1,4,7,10-tetraazacyclododecane) units of Ru2, appended to the 4,4′ position of a metal-coordinated bipyridyl ligand affords the formation of highly charged species in aqueous media. 31,33 This confers to the resulting Ru(II) complexes not only excellent water solubility, a necessary prerequisite for their biological applications, but also strengthens their interaction with important biological targets, such as DNA. On the other hand, the polyamino-modified bipyridyl frameworks do not affect the good 1 O 2 sensitizing capabilities of Ru1 and Ru2 (Φ Δ(Ru1) = 0.29 ± 0.06 and Φ Δ(Ru2) = 0.38 ± 0.08 in air-saturated CH 3 CN, λ = 400 nm), thus making them attractive PS agents for the light-promoted 1 O 2 generation directly in aqueous media.…”

Advanced Optical Sensing of Phenolic Compounds for Environmental Applications

“…The quenching effect is not remarkable, but the appropriately designed complexes can be used for determining BPA concentration in water. A linear calibration range up 50 µM BPA concentration has been obtained (see Figure 14) by using the luminescence quenching effect [80].…”

“…Calibration curve for different BPA concentration obtained by using the ratio of luminescence intensity of the [Ru (phen)2 L]2+ complex over luminescence intensity of the complex upon addition of increasing concentration. (Reprinted from [80] under Open Access conditions).…”