Skip to Content
Merck
  • Comparative photo-release of nitric oxide from isomers of substituted terpyridinenitrosylruthenium(II) complexes: experimental and computational investigations.

Comparative photo-release of nitric oxide from isomers of substituted terpyridinenitrosylruthenium(II) complexes: experimental and computational investigations.

Dalton transactions (Cambridge, England : 2003) (2014-07-12)
Joëlle Akl, Isabelle Sasaki, Pascal G Lacroix, Isabelle Malfant, Sonia Mallet-Ladeira, Patricia Vicendo, Norberto Farfán, Rosa Santillan
ABSTRACT

The 4'-(2-fluorenyl)-2,2':6',2''-terpyridine (FT) ligand and its cis(Cl,Cl)- and trans(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6) complexes have been synthesized. Both isomers were separated by HPLC and fully characterized by (1)H and (13)C NMR. The X-ray diffraction crystal structures were solved for FT (Pna21 space group, a = 34.960(4), b = 5.9306(7), c = 9.5911(10) Å), and trans(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6)·MeOH (P1[combining macron] space group, a = 10.3340(5), b = 13.0961(6), c = 13.2279(6) Å, α = 72.680(2), β = 70.488(2), γ = 67.090(2)°). Photo-release of NO˙ radicals occurs under irradiation at 405 nm, with a quantum yield of 0.31 and 0.10 for cis(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6) and trans(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6), respectively. This significant difference is likely due to the trans effect of Cl(-), which favors the photo-release. UV-visible spectroscopy and cyclic voltammetry indicate the formation of ruthenium(iii) species as photoproducts. A density functional theory (DFT) analysis provides a rationale for the understanding of the photo-physical properties, and allows relating the weakening of the Ru-NO bond, and finally the photo-dissociation, to HOMO → LUMO excitations.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
2-Acetylpyridine, ≥99%
USP
2-Acetylpyridine, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
2-Acetylpyridine, ≥99%, FG