Four Discrete Silver Iodobismuthates/Bromobismuthates with Metal Complexes: Syntheses, Structures, Photocurrent Responses, and Theoretical Studies.

Using in situ formed metal complexes of [Fe(bipy) 3 ] 2+ or [Ni(bipy) 3 ] 2+ (bipy = 2,2'-bipyridine) as templates, four new Ag-Bi-X (X = I and Br) compounds are first isolated in the metal-complex-decorated heterometallic halobismuthate family, namely [M(bipy) 3 ]AgBiI 6 (M = Fe ( 1 ), Ni ( 2 )), [Fe(bipy) 3 ]AgBiBr 6 ( 3 ), and [Ni(bipy) 3 ]AgBiBr 6 ( 4 ). Compounds 1 - 4 feature discrete [AgBiX 6 ] n 2 n - anions, exhibiting three polymorphisms that may be ascribed to the different stackings and the flexible condensations of [BiX 6 ] octahedrons and [AgX 4 ] tetrahedra/[AgX 3 ] triangles. UV-vis diffuse reflectance analyses reveal that they are narrow band gap semiconductor materials (ca. 1.82-2.13 eV). Intriguingly, the title compounds display excellent photoelectrical switching properties, with photocurrent density following the order 3 > 4 > 2 > 1 . In addition, the comparative studies of intermolecular interactions, theoretical band structures, density of states, and effective masses of three polymorphisms have also been investigated.