DFT study on chemical N2 fixation by using a cubane-type RuIr3S4 cluster: Energy profile for binding and reduction of N2 to ammonia via Ru-N-NHx (x = 1-3) intermediates with unique structures

Hiromasa Tanaka, Hiroyuki Mori, Hidetake Seino, Masanobu Hidai, Yasushi Mizobe, Kazunari Yoshizawa

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)


The N-N bond activation of the dinitrogen ligand in the cubane-type mixed-metal sulfido cluster, [(Cp*Ir)3{Ru(tmeda)(N 2)}(μ3-S)4] (tmeda = Me2NCH 2CH2NMe2), is investigated by using DFT calculations at the B3LYP level of theory. The elongated N-N bond distance, red-shifted N-N stretching, and negatively charged N2 ligand indicate that the dinitrogen is reductively activated by complexation. The degree of the N-N bond activation is classified into the "moderately activated" category, [Studt, F.; Tuczek, F. J. Comput. Chem. 2006, 27, 1278] as in the Mo-triamidoamine complex that can catalyze N2 reduction [Yandulov, D. V.; Schrock, R. R. Science 2003, 301, 76]. Availability of the RuIr 3S4 cluster as a catalyst for N2 reduction is discussed by optimizing possible intermediates in a catalytic cycle analogous to that proposed by Yandulov and Schrock. A calculated energy profile of the catalytic cycle demonstrates that the RuIr3S4 cluster can transform dinitrogen into ammonia in the presence of lutidinium cation and Cp*2Co as proton and electron sources, respectively. The RuIr3S4 clusters with an NNHx (x = 1-3) ligand, which are intermediates in the catalytic cycle, have a significantly bent Ru-N-N linkage, although precedent NNHx complexes generally adopt a linear M-N-N array. The unique structures of the nitrogenous ligands in these intermediates are interpreted in terms of the bonding interaction between the hydrogen atom bonded to the N2 ligand and the adjacent iridium atom in the cuboidal RuIr3S4 framework.

Original languageEnglish
Pages (from-to)9037-9047
Number of pages11
JournalJournal of the American Chemical Society
Issue number28
Publication statusPublished - Jul 16 2008

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


Dive into the research topics of 'DFT study on chemical N<sub>2</sub> fixation by using a cubane-type RuIr<sub>3</sub>S<sub>4</sub> cluster: Energy profile for binding and reduction of N<sub>2</sub> to ammonia via Ru-N-NH<sub>x</sub> (x = 1-3) intermediates with unique structures'. Together they form a unique fingerprint.

Cite this