Highly phosphorescent dinuclear Cu(I) complexes with iminephosphine tetradentate chelating ligand (PNNP): Structures and luminescence properties

[Display omitted] •Two dinuclear copper(I) complexes based on a new iminephosphine tetradentate chelating ligand (PNNP) have been synthesized.•The crystal structures of the complexes display distorted tetrahedron configurations around Cu(I) centers.•Two complexes in powder at 298 K exhibit bright phosphorescence with PLQY up to 66.8%.•The complex 2 exhibits reversible mechanochromic luminescent (MCL) properties. Two dinuclear copper(I) iodide complexes [Cu(μ-I)]2L (1) and [CuIPPh3]2L (2), based on a new iminephosphine tetradentate chelating ligand (PNNP), have been synthesized and characterized. The crystal structures of the complexes display distorted tetrahedron configurations around Cu(I) centers. In powder at 298 K, these complexes exhibit bright orange-red and yellow emissions with excellent photo-luminescent quantum yields of 54.6% (1) and 66.8% (2), and short lifetimes of 2.26 μs (1) and 2.32 μs (2), respectively. The reversible mechanochromic luminescent (MCL) properties of complex 2 have been confirmed by monitoring the changes in emission spectra and X-ray diffraction patterns. X-ray crystallography analysis reveals that the unique pore structure filled with CHCl3 molecule is considered to be the origin of MCL properties of 2.