Fluorescent copper(I) complexes: an X-ray diffraction study of complexes of copper(I) iodide and pyridine derivatives of rhombic, [Cu2I2(3Me-py)4], and polymeric structure, [{Cul(2me-py)}∞] and [{Cul(2,4Me2-py)}∞]

Abstract

Three previously unreported forms of complexes of Cul with a pyridine derivative have been isolated and examined by single-crystal X-ray techniques: [Cu₂I₂(3Me-py)₄](1)(3Me-py = 3–methylpyridine), stoicheiometry 1:1:2, monoclinic space group P2₁, a= 7.912(2), b= 19.390(6), c= 8.774(2)Å, β= 102.22(2)°, Z= 2, R= 0.047 for 2 072 observed reflections, crystallizes with isolated rhombohedra of Cu₂I₂, each Cu being co-ordinated to two ligand molecules via the nitrogen atoms; [{Cul(2Me-py)}_∞](2) and [{Cul(2,4Me₂-py)}_∞](3)(2,4Me₂-py = 2,4-dimethylpyridine), stoicheiometries 1:1:1, (2), monoclinic space group P2₁/a, a= 11.834(5), b= 14.914(6), c= 4.381(2)Å, β= 93.80(4)°, Z= 4, R= 0.078 for 1 082 reflections, (3), triclinic spice group P, a= 11.648(8), b= 4.328(3), c= 10.198(4)Å, α= 77.64(5), β= 68.45(4), γ= 104.25(5)°, R= 0.063 for 1 731 reflections. Both (2) and (3) crystallize as edge-sharing Cu₂I₂ rhombs, with each copper atom bound to three iodide atoms and the nitrogen atom of a molecule of the Lewis base.