Iodobismuthate(III) and Iodobismuthate(III)/Iodocuprate(I) Complexes with Organic Ligands.

Pyridine ligand complexes of [Bu4N][BiI4] were prepared using chelating ligands 2,2'-bipyridyl (2,2'-Bpy), 1,10-phenanthroline (Phen), and 4-nitro-1,10-phenanthroline (NO2Phen), producing monomeric complexes [Bu4N][(2,2'-Bpy)BiI4], [Bu4N][(Phen)BiI4], and [Bu4N][(NO2Phen)BiI4], and bridging ligands 4,4'-bipyridyl (4,4'-Bpy), pyrazine (Pyz), and aminopyrazine (NH2Pyz) resulting in formation of polymers [Bu4N]n[(4,4'-Bpy)BiI4]n and [Bu4N]2n[(RPyz)Bi2I8]n (R=H,NH2). The latter contain edge-sharing Bi2I8 dimers. Organic ligand BiIII/CuI clusters [Bu4N]2[L2Bi2Cu2I10] {L = PPh3,P(OPh)3} and [Bu4N]2[PyBi2Cu2I10] (Py = pyridine) have been prepared. All bismuthate(III) centers are distorted octahedra and all cuprate(I) centers are tetrahedral, with organic ligands bonded to CuI.The first neutral BiI3/CuI organic ligand complex [BiCu3I6(PPh3)6] is reported. Diffuse reflectance spectroscopy measurements reveal strong absorption bands for both iodobismuthate(III) and iodocuprate(I)/bismuthate(III) complexes in the UV and visible range. Despite the similarity in absorption bands, DFT calculations support a distinct shift in transition from a mixed halide/ metal-to-ligand charge transfer (X/MLCT) to a metal--halide cluster-centered transition upon incorporation of copper(I) into the cluster. [ABSTRACT FROM AUTHOR]