Luminescent [Cu8I8L6] wheel and [Cu2I2L3] cage assembled from CuI and 3,6-bis(diphenylphosphino)pyridazine

The reaction of CuI and 3,6-bis(diphenylphosphino)pyridazine (dppz) in MeCN leads to the wheel-shaped complex [Cu₈I₈(dppz)₆], assembled from four [Cu₂I₂] units and six dppz ligands. This complex exhibits thermochromic luminescence with emission colors ranging from red (300 K) to deep red (77 K). When carried out in the presence of PPh₃, the reaction of CuI with dppz gives a non-emissive cage-like complex [Cu₂I₂(dppz)₃], in which two CuI units are P,P′-bridged by three dppz ligands.