Rapid reduction of nitric oxide to dinitrogen by zirconium(II): Kinetic studies on a reaction controlled by gas-liquid transport

Kristopher McNeill, Robert G. Bergman

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Nitric oxide reacts with Cp2Zr(PMe3)2 (1; Cp = η5-C5H5) in THF or toluene to yield dinitrogen and an oligomeric oxozirconocene species, [Cp(x)ZrO(y)](n). The reduction of NO occurs in two distinct steps: 1 reduces 2 equiv of NO to 1 equiv of N2O, and then 1 reduces N2O to N2. In each step, 1 is converted to a monomeric oxozirconocene species [Cp2ZrO], which may be trapped by the addition of Me3SiCl or Cp2ZrMe2, to form Cp2Zr(OSiMe3)(C1) and [Cp2ZrMe]2O, respectively. Kinetics for the reduction of NO by 1 were followed at low temperature (160 < T < 195 K) by monitoring the change in pressure of the system. Complete reaction was observed in less than 15 s, even at the lowest temperatures. The typical kinetic trace displayed two decay regimes, zero- and first-order, which were interpreted as the result of competing mass-transfer and chemical reaction processes. The kinetic results support a rate-limiting bimolecular reaction between NO and 1. The subsequent intermediates and mechanistic possibilities are discussed.

Original languageEnglish (US)
Pages (from-to)8260-8269
Number of pages10
JournalJournal of the American Chemical Society
Volume121
Issue number36
DOIs
StatePublished - Sep 15 1999

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