Copper(I) iodide complexes with cyanopyridine and 3-nitropyridine ligands

Abstract

The complexes of copper(I) iodide with the three cyanopyridine (PyCN) isomers and 3-nitropyridine have been prepared and characterized by thermal, spectroscopic, and crystallographic methods. The following compounds are reported: (CuI)2(2-PyCN)4 (1), (CuI)(2-PyCN) (2), (CuI)3(2-PyCN) (3), (CuI)2(3-PyCN)4 (4), (CuI)(3-PyCN) (5), (CuI)4(4-PyCN)5 (6), (CuI)4(3-PyNO2)4 (7), and (CuI)(3-PyNO2) (8). Compounds 1 and 4 are isostructural dimers featuring a central Cu2I2 rhomb. Compounds 2, 5, and 8 are isostructural and contain edge-sharing (Cu2I2)∞ 1-D ladders. Compound 3 reveals a unique 2-D structure consisting of (Cu4I4)∞ triple ladders bridged by Cu2(2-PyCN)2 units that contain pairs of bridging 2-PyCN ligands. Compound 6 is composed of truncated ladder (CuI)4(4-PyCN)4 units that are bridged into a 1-D chain by an additional 4-PyCN ligand. Compound 7 is a cubane tetramer. The various yellow and orange PyCN compounds are all luminescent under UV irradiation and exhibit mixed halide/metal-to-ligand charge transfer, while the red and orange PyNO2 complexes are non-emissive at room temperature.