Preparation of copper(I) pseudo-rotaxanes from bis-phosphine ligands

The preparation of heteroleptic Cu complexes from various 2,9-disubstituted-1,10-phenanthrolines (phen) and different bis-phosphine (PP) ligands was investigated. These heteroleptic complexes are found to be stable in CH ₂Cl ₂ solutions and no detectable ligand exchange reactions could be detected. The results also show that the CuI-mediated threading of all the bis-phosphine ligands through the macrocycle is effective. The X-ray crystal structure analysis of BF ₄ proves the threading of the POP moiety through the macrocyclic phenanthroline ligand. The intramolecular face-to-face p p interaction between one phenyl ring of the POP ligand and the phenanthroline moiety induces a significant rocking of the POP ligand. The results also show that formation of the homoleptic bisphenanthroline Cu complex is prevented by the macrocyclic nature of the phenanthroline ligand.