Preparation, Characterization, Electrochemistry, and Infrared Spectroelectrochemistry of Ruthenium Nitrosyl Porphyrins Containing η 1-O-Bonded Axial Carboxylates

Dennis Awasabisah, Nan Xu, Krishna P.Sharmah Gautam, Douglas R. Powell, Michael J. Shaw, George B. Richter-Addo

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The synthesis, characterization and redox behavior of eight low-spin nitrosyl carboxylate compounds (por)Ru(NO)[η1-OC(=O)R] [por = T(p-OMe)PP: R = Me (1), iPr (2), tBu (3), p-C6H4NO2 (4), Fc (5), CF3 (8); por = TTP: R = Fc (6)] and [T(p-OMe)PP]Ru(NO)(OC6HF4) (7) are reported. The compounds are moderately stable in air as solids. Their IR (KBr) spectroscopic data show NO's in the 1839-1861 cm-1 range. The X-ray crystal structures of compounds 1, 2, 5-7, and 8 have been determined, and reveal linear RuNO linkages for these formally {RuNO}6 complexes. The redox behavior of the compounds at a Pt working electrode were studied in CH2Cl2 with NBu4PF6 as supporting electrolyte. The compounds display reversible first oxidations. IR spectroelectrochemistry of compounds 1-4, 7 and 8 revealed porphyrin-centered oxidations, whereas the ferrocenylcarboxylate compounds revealed first oxidations at the ferrocenyl moiety followed by second oxidations at the porphyrin macrocycles. Reductions of these compounds are accompanied by loss of the axial ligands. The redox behavior of a representative set of Ru porphyrin nitrosyls with η1-O-carboxylate ligands reveal that the first oxidations occur at the porphyrin macrocycles. Appending redox-active ferrocenylcarboxylates to the (por)Ru(NO) centers alters the oxidation behavior such that the first oxidations occur on the ferrocenyl moieties. X-ray crystallographic data were obtained for six of these derivatives that show essentially linear RuNO linkages consistent with their {RuNO}6 descriptions.

Original languageEnglish (US)
Pages (from-to)509-518
Number of pages10
JournalEuropean Journal of Inorganic Chemistry
Volume2016
Issue number4
DOIs
StatePublished - Feb 1 2016

All Science Journal Classification (ASJC) codes

  • Inorganic Chemistry

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