Experimental Identification of the Active Site in the Heteronuclear Redox Couples [AlVOx ]+. /CO/N2 O (x=3, 4) by Gas-Phase IR Spectroscopy.

Cryogenic ion vibrational spectroscopy was used in combination with electronic structure calculations to identify the active site in the oxygen atom transfer reaction [AlVO4 ]+. +CO→[AlVO3 ]+. +CO2 . Infrared photodissociation spectra of messenger-tagged heteronuclear clusters demonstrate that in contrast to [AlVO4 ]+. , [AlVO3 ]+. is devoid of a terminal Al-Ot unit while the terminal V=Ot group remains intact. Thus it is the Al-Ot moiety that forms the active site in the [AlVOx ]+. /CO/N2 O (x=3, 4) redox couples, which is in line with theoretical predictions.