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

Pyridine ligand complexes of [Bu 4 N][BiI 4 ] were prepared using chelating ligands 2,2′‐bipyridyl (2,2′‐Bpy), 1,10‐phenanthroline (Phen), and 4‐nitro‐1,10‐phenanthroline (NO 2 Phen), producing monomeric complexes [Bu 4 N][(2,2′‐Bpy)BiI 4 ], [Bu 4 N][(Phen)BiI 4 ], and [Bu 4 N][(NO 2 Phen)BiI 4 ], and bridging ligands 4,4′‐bipyridyl (4,4′‐Bpy), pyrazine (Pyz), and aminopyrazine (NH 2 Pyz) resulting in formation of polymers [Bu 4 N] n [(4,4′‐Bpy)BiI 4 ] n and [Bu 4 N] 2n [(RPyz)Bi 2 I 8 ] n (R = H, NH 2 ). The latter contain edge‐sharing Bi 2 I 8 dimers. Organic ligand Bi III /Cu I clusters [Bu 4 N] 2 [L 2 Bi 2 Cu 2 I 10 ] {L = PPh 3 , P(OPh) 3 } and [Bu 4 N] 2 [PyBi 2 Cu 2 I 10 ] (Py = pyridine) have been prepared. All bismuthate(III) centers are distorted octahedra and all cuprate(I) centers are tetrahedral, with organic ligands bonded to Cu I . The first neutral BiI 3 /CuI organic ligand complex [BiCu 3 I 6 (PPh 3 ) 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.