Synthesis,X-ray Structures,and Photoluminescence of the Octahedral Cu4I4 Cluster with Bulky Bidentate Bis(phosphanyl)amine Ligand

The reaction of C₁₀H₇-1-N(PPh₂)₂ ( 1 ) with two equivalents of CuI in acetonitrile resulted in the formation of octahedron Cu₄I₄ 1 ]₂ complex ( 2 ). The crystal structure of 2 showed it adopted a rare octahedral arrangement. The rectangular Cu₄ plane is μ⁴-capped by two of the iodides and is placed in axial positions above and below the Cu₄-plane form an octahedron, whereas the other two iodides are bonded to two copper atoms in a μ²-fashion. The luminescence of complex 2 arises from a triplet halide-to-ligand charge transfer (³XLCT) excited state and ³CC (Cu₄I₄ cluster-centered) excited state are not involved in the luminescence by the rigid bidentate ligand 1 in spite of the short Cu^I–Cu^I bond length. Complex 2 was identified and characterized by multinuclear NMR (¹H, ¹³C, ³¹P NMR) and IR spectroscopy. Crystal structure determinations of 1 and 2 were carried out.