Luminescent Charge‐Neutral Copper(I) Phenanthroline Complexes with Isocyanoborate Ligand

Copper(I) complexes with thermal activated delayed fluorescence (TADF) have attracted considerable attention for the development of emissive materials in organic light‐emitting devices. However, many emissive CuI complexes are cationic emitters and cannot be vacuum‐sublimed, a process used for device fabrication. This has limited their applications in devices. In this work we have developed a series of emissive charge‐neutral CuI complexes with the general formula [Cu(2,9‐Me2phen)(CNR){CNB(C6F5)3}] [R = 2,6‐Me2C6H3, 2,6‐iPr2C6H3, 2,4,6‐Cl3C6H2, 2,4,6‐Br3C6H2, 3,5‐(CF3)2C6H3, 4‐SF5C6H4] through the incorporation of a strong π‐accepting anionic isocyanoborate ligand. All the complexes have been structurally characterized and their photophysical properties have been studied. A series of luminescent charge‐neutral isocyanoborato copper(I) diimine complexes have been synthesized and structurally characterized. A detailed photophysical study revealed that these complexes exhibit 1MLCT emission in the solid state at room temperature, whereas they show dual emission derived from a 3MLCT and 3LC excited‐state origin in low‐temperature glassy media.