Synthesis and Crystal Structure of a Copper(II) Benzoate Complex Bearing a Bis-2,2′-Tetrahydrofuryl Peroxide Moiety

Complex [Cu2(ben)4·2THF−(η1–O2)]∞ (2) (ben=C6H5CO2− benzoate; THF=tetrahydrofuran) was isolated when a solution of Cu2(ben)4·2THF (1) in THF upon natural sunlight irradiation yields crystals suitable for single-crystal X-ray diffraction analysis. 2, crystallized in the C2/c monoclinic space group, Z=8, V=3394.2 (4) Å3, and the unit cell parameters a=9.7935(7) Å, b=19.0055 (13) Å, c=18.2997 (13) Å, α=90°, β=94.7996 (11)º and γ=90°. This is the first example of a polymeric copper(II) carboxylate compound stabilizing a peroxo group via its apical ligand (THF molecule). Additionally, 2 was also characterized by elemental analysis, Fourier-transformed infrared spectroscopy (FTIR) and Raman spectroscopyUniversidad de Costa Rica/[804-B7-279]/UCR/Costa RicaUniversidad de Costa Rica/[804-B0-650]/UCR/Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de QuímicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Electroquímica y Energía Química (CELEQ

X‐ray photoelectron spectroscopy of Nd2−xCexCuO4−y (x=0 and 0.15) thin films

Electronic structure of Nd2−xCexCuO4−y (x=0 and 0.15) thin films was examined by x-ray photoelectron spectroscopy. The films were prepared by rf magnetron sputtering and successive annealing under reducing condition (reduction). The reduced films showed semiconducting and superconducting behaviors depending on the value x. The Cu, O, and Nd core-level spectra revealed that the doped electrons were predominantly in CuO2 plane of the Nd2CuO4 crystal. The Cu core-level spectra from x=0.15 films before and after the reduction suggested that the reduction added electrons to Cu4s-O2p extended conduction band, and strengthened Cu O bond covalency to screen the core hole state by mobile itinerant electrons. Journal of Applied Physics is copyrighted by The American Institute of Physics