A Short Copper-Copper Distance in a (µ-1,2-Peroxo)dicopper(II) Complex Having a 1,8-Naphthyridine Unit as an Additional Bridge This work was supported by grants from the National Science Foundation and the National Institutes of Health. We thank A. M. Barrios for help in acquiring resonance Raman spectra. X-ray absorption spectroscopic data were measured at SSRL. SSRL is funded by the Department of Energy, Office of Basic Energy Science. The SSRL Structural Molecular Biology Program is supported by the National Institute of Health, National Center for Research Resources, Biomedical Technology Program, and by the Department of Energy, Office of Biological and Environmental Research.