Syntheses, crystal structures, and optical properties of polymeric iodoargentates containing transition metal-complexes with aromatic ligands

Abstract

Six new iodoargentates [Mn(2,2′-bipy)2(DMSO)2]Ag5I7 (1), [Mn(2,2′-bipy)2(DMF)2]Ag5I7 (2), [Zn(2,2′-bipy)2(DMF)2]Ag5I7 (3), [{Cd(2,2′-bipy)2}2(μ4-Ag2I6)] (4), [{Zn(DMF)2(H2O)2}(4,4′-bipy)1.5]Ag5I7·2DMF (5) and [Zn(4,4′-bipy)2(DMSO)2(H2O)2]Ag10I12·2DMSO·2H2O (6) (2,2′-bipy = 2,2′-bipyridine; 4,4′-bipy = 4,4′-bipyridine; DMF = N,N'-dimethylformamide; DMSO = dimethylsulfoxide) were prepared using transition metal complex cations as counter ions. The charge balance TM2+-2,2′-bipy (TM = Mn, Zn) complex cations modified by small ligands via solvating in different polar solvents lead to formation of γ-[Ag5I72−]n chains in compounds 1–3, while the [Cd(2,2′-bipy)2]2+ cation affords a binuclear neutral complex 4 which contains a novel tetradentate μ-Ag2I6 ligand. The solvated Zn2+-4,4′-bipy complex cation results β-[Ag5I72−]n and [Ag10I12]2– chain-like anions in 5 and 6, respectively. All the polymeric γ-[Ag5I72−]n, β-[Ag5I72−]n, μ-Ag2I6 and [Ag10I12]2– units are formed by the primary tetrahedral AgI4 units via corner- or edge-sharing. Compounds 1–6 show well-defined absorption edges with band gaps in the range of 2.68 to 2.86 eV at room temperature. Compounds 2 and 5 display higher catalytic activities than 4 in the photodegradation of organic dye CV. All ∙O2−, ·OH and h+ reactive species play an important role in the photodegradation of CV over compound 2, while ·OH are the main reactive species in the photocatalytic reaction using compound 5 as catalyst.