Anion Photoelectron Spectroscopy and Quantum Chemical Calculations of Bimetallic Oxide Clusters YCu2On–/0 (n = 2–5)

The structural and electronic properties of bimetallic oxide clusters, YCu₂O_n^- and YCu₂O_n (n = 2-5), are investigated using anion photoelectron spectroscopy and density functional theory calculations. The experimental vertical detachment energies of YCu₂O₂^-, YCu₂O₃^-, YCu₂O₄^-, and YCu₂O₅^- were measured to be 1.59, 1.76, 3.85, and 3.78 eV, respectively. Vibrationally resolved photoelectron spectra have been obtained for YCu₂O₂^-, with a spacing of 726 ± 80 cm^-1 assigned to the Y-O stretching vibrational mode. It is found that YCu₂O₂^- and YCu₂O₂ have C_2v symmetric planar five-membered ring structures. YCu₂O₃^- and YCu₂O₃ have C_2v symmetric planar six-membered ring structures. The most stable structure of YCu₂O₄^- is a quasi-planar structure which can be viewed as one O atom interacting with the Y atom of the YCu₂O₃ six-membered ring, while the most stable structure of YCu₂O₄ is a planar seven-membered ring. YCu₂O₅^- and YCu₂O₅ have nonplanar structures, which can be viewed as an O₂ unit interacting with the Y atom of the YCu₂O₃ six-membered ring. In YCu₂O_3,4,5^-/0, the Y-O and Cu-O bonds are dominant, while the Y-Cu and Cu-Cu interactions are weak.