“…[15] In rare cases, Cu I can have other coordination environments, including linear, [1] trigonal, [1] and trigonal pyramidal. [16] [a] Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University P. O. Box 9502, 2300 RA Leiden, The Netherlands [b] Bijvoet Center for Biomolecular Research, Vakgroep Kristalen Structuurchemie, Utrecht University Padualaan 8, 3584 CH Utrecht, The Netherlands E-mail: haasnoot@chem.leidenuniv.nl mon eight-atom chelate ring with the copper ion.…”