skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Synthesis, Protonation, and Reduction of Ruthenium–Peroxo Complexes with Pendent Nitrogen Bases

Abstract

Cyclopentadienyl and pentamethylcyclopentadienyl ruthenium(II) complexes have been synthesized with cyclic (RPCH 2NR'CH 2) 2 ligands, with the goal of using these [Cp R"Ru(P R 2N R' 2)] + complexes for catalytic O 2 reduction to H 2O (R = t-butyl, phenyl; R' = benzyl, phenyl; R" = methyl, H). In each compound, the Ru is coordinated to the two phosphines, positioning the amines of the ligand in the second coordination sphere where they may act as proton relays to a bound dioxygen ligand. The phosphine, amine, and cyclopentadienyl substituents have been systematically varied in order to understand the effects of each of these parameters on the properties of the complexes. These Cp R"Ru(P R 2N R' 2) + complexes react with O 2 to form η 2-peroxo complexes, which have been characterized by NMR, IR, and X-ray crystallography. The peak reduction potentials of the O 2 ligated complexes have been shown by cyclic voltammetry to vary as much as 0.1 V upon varying the phosphine and amine. In the presence of acid, protonation of these complexes occurs at the pendent amine, forming a hydrogen bond between the protonated amine and the bound O 2. The ruthenium–peroxo complexes decompose upon reduction,more » precluding catalytic O 2 reduction. Finally, the irreversible reduction potentials of the protonated O 2 complexes depend on the basicity of the pendent amine, giving insight into the role of the proton relay in facilitating reduction.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1054467
Report Number(s):
PNNL-SA-88856
Journal ID: ISSN 0020-1669; KC0307010
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 51; Journal Issue: 20; Journal ID: ISSN 0020-1669
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English

Citation Formats

Tronic, Tristan A., Kaminsky, Werner, Coggins, Michael K., and Mayer, James M. Synthesis, Protonation, and Reduction of Ruthenium–Peroxo Complexes with Pendent Nitrogen Bases. United States: N. p., 2012. Web. doi:10.1021/ic3013987.
Tronic, Tristan A., Kaminsky, Werner, Coggins, Michael K., & Mayer, James M. Synthesis, Protonation, and Reduction of Ruthenium–Peroxo Complexes with Pendent Nitrogen Bases. United States. doi:10.1021/ic3013987.
Tronic, Tristan A., Kaminsky, Werner, Coggins, Michael K., and Mayer, James M. Mon . "Synthesis, Protonation, and Reduction of Ruthenium–Peroxo Complexes with Pendent Nitrogen Bases". United States. doi:10.1021/ic3013987.
@article{osti_1054467,
title = {Synthesis, Protonation, and Reduction of Ruthenium–Peroxo Complexes with Pendent Nitrogen Bases},
author = {Tronic, Tristan A. and Kaminsky, Werner and Coggins, Michael K. and Mayer, James M.},
abstractNote = {Cyclopentadienyl and pentamethylcyclopentadienyl ruthenium(II) complexes have been synthesized with cyclic (RPCH2NR'CH2)2 ligands, with the goal of using these [CpR"Ru(PR2NR'2)]+ complexes for catalytic O2 reduction to H2O (R = t-butyl, phenyl; R' = benzyl, phenyl; R" = methyl, H). In each compound, the Ru is coordinated to the two phosphines, positioning the amines of the ligand in the second coordination sphere where they may act as proton relays to a bound dioxygen ligand. The phosphine, amine, and cyclopentadienyl substituents have been systematically varied in order to understand the effects of each of these parameters on the properties of the complexes. These CpR"Ru(PR2NR'2)+ complexes react with O2 to form η2-peroxo complexes, which have been characterized by NMR, IR, and X-ray crystallography. The peak reduction potentials of the O2 ligated complexes have been shown by cyclic voltammetry to vary as much as 0.1 V upon varying the phosphine and amine. In the presence of acid, protonation of these complexes occurs at the pendent amine, forming a hydrogen bond between the protonated amine and the bound O2. The ruthenium–peroxo complexes decompose upon reduction, precluding catalytic O2 reduction. Finally, the irreversible reduction potentials of the protonated O2 complexes depend on the basicity of the pendent amine, giving insight into the role of the proton relay in facilitating reduction.},
doi = {10.1021/ic3013987},
journal = {Inorganic Chemistry},
issn = {0020-1669},
number = 20,
volume = 51,
place = {United States},
year = {2012},
month = {10}
}