Tricarbonyls of low-coordinated Au(0) atoms in zeolite-supported gold nanoparticles: Evidence from infrared and X-ray absorption spectroscopies

Mononuclear gold complexes in zeolite NaY were synthesized from initially physisorbed Au(CH3)(2)(C5H7O2) and characterized by X-ray absorption and infrared spectra recorded as the samples were exposed to flowing CO. X-ray absorption spectra demonstrate the formation of zero-valent gold nanoparticles during the CO treatment. Three new nu(CO) bands grew in during this treatment, at 2070, 2033, and 2000 cm(-1), characteristic of carbonyls of Au-0. Because the relative intensities of these bands decreased monotonically when the flow of CO was replaced by flowing He, it is inferred that they correspond to a single Au (CO)(3) species, on low-coordinated Au atoms. This is the first example of an Au-0 (CO)(3) species.