A New Member of the Growing Family of Interconvertible {RuNO}6, 7, 8 Species. Redox and Acid‐Base Characterization of [Ru((CH2py)2Me[9]aneN3)(NO)]n+. Issue 46 (1st December 2021)

• Record Type: Journal Article
• Authors: Perdoménico, Julián; Levin, Natalia; Fierro, Anabella C.; Cordero Chernek, Oswaldo A.; Weyhermüller, Thomas; Slep, Leonardo D.
• Is Part Of: European journal of inorganic chemistry. Issue 46(2021)
• Page Start: 4842
• Page End: 4855
• Publication Date: 2021-12-01
• Subjects: Azanone -- Density functional calculations -- Nitrosyl compounds -- Redox chemistry -- Ruthenium; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.202100753
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: The preparation and characterization of a new ruthenium nitrosyl based on the pentadentate ligand (CH2 py)2 Me[9]aneN3 (1‐methyl‐4, 7‐bis(pyridin‐2‐ylmethyl)‐1, 4, 7‐triazacyclononane) is reported. The octahedral species contains a {RuNO} 6 fragment and can be isolated in the solid state as a PF6 − salt. In acetonitrile, this platform allows exploring the reduction processes in 1‐electron steps from {RuNO} 6 to {RuNO} 8, with associated E ° values of 0.421 V and −0.628 V ( vs . Ag/AgCl, 3 M NaCl), respectively. The {RuNO} 7 species is paramagnetic, its EPR spectrum in vitrified acetonitrile at 90 K is consistent with an S= 1 / 2 center with g=(2.0095, 1.9992, 1.8785) coupled to a 14 N nucleus, with A=(6.9, 30.24, 1.85)×10 −4 cm −1 . In acidified aqueous solution, the first reduction process at 0.101 V leads to the formation of {RuNO} 7, as in aprotic medium (acetonitrile). However, the incorporation of a second electron is coupled to a protonation process of the nitroxyl group, generating a coordinated azanone (HNO) compound with p K a (HNO)=11.0. Spectroscopic information obtained via spectroelectrochemistry and electronic structure calculations assist in the rationalization of results. Overall, this new compound enhances the library of nitrosylated Ru species with combined redox, acid‐base, and spectroscopic characterization in water and confirms experimental correlations found in related species. Abstract : A new example of the growing library of species designed to explore key aspects of the behavior of coordinated nitrosyl in biological processes confirms correlations between the p K a of bound HNO and redox properties of the complexes.