Lewis-base adducts of Group 11 metal(I) compounds. Part 58. Syntheses, X-ray structures, and far-infrared spectra of the novel [CuX2(bidentate ligand)]–(X = Cl or Br) anion salts of the [Cu(dpa)2]+cation and the dimeric iodide [(dpa)Cul2Cu(dpa)][dpa = di(2-pyridyl)amine]

Reaction of copper(i) halides (CuX, X = CI, Br, or I) in acetonitrile solution with di(2- pyridyl)amine(dpa) yields 1 : 1.5 adducts with the chloride and bromide, a 1 : 1 adduct with the iodide, and a 1 : 2 adduct with the chloride. The compounds have been characterized by spectroscopic and single-crystal X-ray methods. The 1 : 1 iodide is a dimer, [(dpa)Cul,Cu(dpa)], of a type familiar with other bidentate nitrogen base ligands, but the 1 : 1.5 complexes are ionic, formulated as [Cu(dpa),] + [Cu(dpa)X,] -, containing the first structurally characterized [Cu(dpa),] +- cations and [CuX,(bidentate ligand)] - anions, while the 1 : 2 chloride is [Cu(dpa),] 'CI-. In the [Cu(dpa),] + cation mean CU-N is ca. 2.00 A, while in the [Cu(dpa)X,] - anions Cu-N is ca. 2.05 A and Cu-CI and Cu-Br 2.369(2), 2.302(2) and 2.490(6), 2.439(6) A respectively. The dpa ligand in all cases is essentially planar. The far i.r. spectra of the anions show bands at 21 4 cm-' (chloride) and 160 cm-' (bromide) which can be assigned to the asymmetric stretching mode of the CuX, unit.Full Tex