Anion Photoelectron Spectroscopy and Quantum Chemical Calculations of LaCu₂O_n^−/0 (n=4, 5): Interaction between Oxygen Unit and LaCu₂O₃ Six-Membered Ring^†

We conducted a joint anion photoelectron spectroscopy and theoretical investigation on hybrid lanthanum-copper oxides clusters, LaCu₂O_n^−/0 (n=4, 5). The experimental vertical detachment energies of LaCu₂O₄‾ and LaCu₂O₅‾ are determined to be 3.70 and 3.79 eV, respectively. Theoretical calculations show that the most stable structures of LaCu₂O_4,5‾ are mainly composed of LaCu₂O₃ six-membered ring, with an additional O atom or O₂ unit interacting with the La atom. In LaCu₂O₄‾, covalent interaction is presented between the external O atom and the LaCu₂O₃ six-membered ring. As for LaCu₂O₅‾ anion, a weak interaction dominated by inductive force is presented between the external O₂ unit and the LaCu₂O₃ six-membered ring.