Syntheses, Crystal Structures, and Photocatalytic Properties of Bromoargentates Induced by Transition-Metal-phen Complex Cations

The bromoargentates [TM(phen)(3)](2)Ag(13)Br(17)2dmso3H(2)O [TM = Fe (1), Co (2), Ni (3)], [Cu(phen)(2)(Br)]AgBr2 (4), [Fe(phen)(3)]Ag(2)Br(4)dmf (5), and [Fe(phen)(2)(Cl)(2)](2)Ag2Br4 (6) (phen = 1,10-phenanthroline) were prepared by the reactions of AgBr, KBr, and phen with transition-metal salts in dimethyl sulfoxide (DMSO) or dimethylformamide (DMF) solvent. In 1-3, AgBr4 tetrahedra form [Ag7Br13] secondary building units (SBUs) through edge sharing. The [Ag7Br13] SBUs interconnected by face sharing form polymeric [Ag13Br174-](n) anions with a 3D structure, and this is the first example of a 3D framework of bromoargentates. The [Ag13Br174-](n) anion contains interpenetrating channels, in which the [TM(phen)(3)](2+) (TM = Fe, Co, Ni) cations and DMSO and H2O molecules are wrapped. The channel along the [111] direction has the largest sectional window constructed by 50 AgBr4 tetrahedra. In 4, the AgBr4 tetrahedra are interlinked by face sharing to form a 1D [AgBr2-](n) polymeric anion. The polymeric [Ag2Br42-](n) anion in 6 has a 1D structure that is similar to that of the [AgBr2-](n) chain in 4. In 5, two AgBr3 trigonal units are joined by edge sharing to form a unique planar dimeric [Ag2Br4](2-) anion. Compounds 1-6 possess narrow band gaps in the range of 2.07 to 2.87 eV. Compounds 4 and 6 exhibit effective photocatalytic activities in the photodegradation of the organic dyes crystal violet and methylene blue under visible-light irradiation at room temperature.