Preparation, Characterization, Electrochemistry, and Infrared Spectroelectrochemistry of Ruthenium Nitrosyl Porphyrins Containing η1-O Bonded Axial Carboxylates

Authors

Dennis Awasabisah, University of Oklahoma Norman Campus
Nan Xu, University of Oklahoma Norman Campus
Krishna P. Sharmah-Gautam, Southern Illinois University Edwardsville
Douglas R. Powell, University of Oklahoma Norman Campus
Michael J. Shaw, Southern Illinois University EdwardsvilleFollow
George B. Richter-Addo, University of Oklahoma Norman Campus

Document Type

Article

Publication Date

Winter 1-29-2016

Department

Chemistry

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), i-Pr (2), t-Bu (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) spectral data show ʋNO's in the 1839-1861 range cm^-1. 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.

Comments

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 moieities. X-ray crystallographic data were obtained for six of these derivatives that show essentially linear RuNO linkages consistent with their {RuNO}⁶ descriptions.

This is the peer reviewed version of the following article:

Awasabisah, D., Xu, N., Gautam, K. P. S., Powell, D. R., Shaw, M. J. and Richter-Addo, G. B. (2016), Preparation, Characterization, Electrochemistry, and Infrared Spectro­electrochemistry of Ruthenium ­Nitrosyl Porphyrins Containing η¹-O-Bonded Axial Carboxylates. Eur. J. Inorg. Chem., 2016: 509–518. doi: 10.1002/ejic.201501115

which has been published in final form at http://dx.doi.org/10.1002/ejic.201501115. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

Recommended Citation

Awasabisah, Dennis; Xu, Nan; Sharmah-Gautam, Krishna P.; Powell, Douglas R.; Shaw, Michael J.; and Richter-Addo, George B., "Preparation, Characterization, Electrochemistry, and Infrared Spectroelectrochemistry of Ruthenium Nitrosyl Porphyrins Containing η1-O Bonded Axial Carboxylates" (2016). SIUE Faculty Research, Scholarship, and Creative Activity. 29.
https://spark.siue.edu/siue_fac/29