Octakis solvated terbium iodide complexes [Tb(DMSO)8]I3 (1) and [Tb(DMF)8]I3 (2) (DMSO = dimethylsulfoxide; DMF = dimethylformamide) were used as synthons to construct novel iodoargentate fabrics. Reaction of 1 with 6 equivalents of AgI in the presence of NH4I produced a novel framework compound [Tb(DMSO)8]2[Ag2(μ-I)3I2][Ag5(μ3-I)4(μ-I)4]2∞ (3) involving alternate layers of discrete [Tb(DMSO)8]3+ cation, [Ag2I5]3− anion and a 2D microporous sheet of the composition [Ag5I8]3−, whereas similar reaction of 2 yielded [Tb(DMF)8][Ag6(μ4-I)2(μ3-I)2(μ-I)5]1∞ (4) with a 1D zigzag structure. The two structural forms are completely inter-convertible on mutual exchange of DMSO and DMF ligands, the partial substitution of the former ligand in 3 yielding a mixed-ligand complex [Tb(DMF)6.7(DMSO)1.3][Ag6(μ4-I)2(μ3-I)2(μ-I)5]1∞ (5). Single crystal X-ray structures are reported for all the complexes. Thermo-gravimetric analyses of these complexes show that thermal stability decreases in the order 4 > 2 > 3 > 1, whereas the diffuse reflectance spectra of 3 and 4 exhibit an optical band gap of about 3.7 eV, thus revealing the insulator nature of these hybrid iodoargentates. Compared to solvated terbium iodide complexes 1 and 2, the high energy transitions in the excitation spectra of the iodoargentate complexes 3 and 4 are quenched by a process which can best be attributed to the auto-ionization of the carriers in the above materials.
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