4,7-Diphenyl-1,10-phenanthroline (dph) forms mono-, bis- and tris- complexes with copper(II). The mono- and tris-complexes appear to be octahedral, the bis-complexes five-coordinate. Although dph readily forms complexes with copper(II), the isolation of copper(I) complexes is more difficult.
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Lip et al. (1975) studied this question.