Low temperature XPS of (η4-cyclooctatetraene)Ru(CO)3

X-ray photoelectron spectroscopy was used to analyze an authentic sample of (η4-cyclooctatetraene)Ru(CO)3 held at 173 K to prevent sublimation of the compound during measurement. This precursor has previously shown utility for photoassisted chemical vapor deposition of Ru species onto alkanethiolate self-assembled monolayers. Herein, we report that the Ru signals for the Ru(0) complex are at a higher binding energy than those of pure Ru metal.