Infrared Matrix-Isolation and Theoretical Study of the Reactions of Ruthenocene with Ozone.

Abstract

The thermal and photochemical reactions of ozone with ruthenocene were studied in argon matrices at 10-15 K by infrared spectroscopy. Irradiation of freshly deposited matrices with near-infrared light (λ = 880 nm) from an LED resulted in new peaks in their infrared spectra that were assigned to three new ruthenocene oxide structures (4, 5, and 6) calculated by the density functional theory. It is proposed that the near-infrared light caused photodissociation of some ozone molecules and subsequent reactions of the atomic oxygen produced with adjacent ruthenocene molecules in the matrix. Structures 4 and 5 contain a Ru=O oxo group resulting from the attack of atomic oxygen on the ruthenium atom, and structure 6 contains a C=O aldehyde group resulting from the attack of atomic oxygen on a ring carbon atom. Subsequent irradiation of the matrix with red light (λ = 625 nm) from an LED resulted in a fourth new structure (7), and it also initiated a reversible photochemical conversion 4 ⇄ 5 + O2, with the forward direction promoted by red light (λ = 625 nm) and the reverse direction promoted by near-infrared light (λ = 880 nm). Structure 7, which contains ruthenium-coordinated cyclopentadienyl, cyclopentadienone, and hydride ion, is the most stable of the four new structures as shown by the calculated energies relative to ruthenocene plus O(3P). Structure 7 is proposed as an intermediate in the chemical vapor deposition and atomic layer deposition of the Ru/RuO2 film forming reactions on substrates at elevated temperatures reported in the literature.