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Under the template of methyl viologen (MV2+ = methyl viologen) and ethyl viologen (EV2+ = ethyl viologen), two new viologen/iodobismuthate hybrids, (MV)5(Bi2I10)(Bi2I9)2 (1) and (EV)3(Bi4I18) (2) have been structurally determined. The highly interesting feature of 1 lies in its combination of two kinds of dimeric iodobismuthate clusters, i.e. (Bi2I10)4− and (Bi2I9)3− in one lattice induced by MV2+, which are constructed from edge- and face-sharing BiI6 octahedra respectively. But the (Bi4I18)6− tetramer in 2 is based on edge- and vertex-sharing BiI6 octahedra. C–H···I hydrogen bonds contribute to the formation of quasi-3-D networks. The smaller gap of 1 might be led by more versatile C–H···I hydrogen bond interactions due to the presence of mixed type iodobismuthate clusters. Two hybrids display reversible thermochromism behaviors. Theoretical calculation suggests that the terminal iodine is dominated in electron transfer of thermochromisms, rather than bridged iodine. [ABSTRACT FROM AUTHOR]

The hybridization of 1,4-bis(isoquinoline)butane (BIQBT2+) cation with iodobismuthate under different solvents produce two isomers α-[(BIQBT)(BiI4)2]n (α-1, in CH3OH/H2O mixed solvent, Triclinic system with P-1 space group) and β-[(BIQBT)(BiI4)2]n (β-1, in CH3OH, Monoclinic system with P21/c space group). The 1-D (BiI4)nn− chains are constructed from the opposite edge-sharing BiI6 octahedra. The (BIQBT)2+ in α-isomer adopts the planar configuration, and that in β-isomer presents the chair-like configuration, as a result, different packing modes (intercalating quasi-3-D mode for α-1 and interlocking 2-D mode for β-1) are observed. Interestingly, from α-1 to β-1, distortion degree of BiI6 octahedron and π–π stacking interaction decrease, but hydrogen bonds number increase. Consequently, due to different packing mode, photoluminescence/thermochromisms can be found in α-1, but those of β-1 are vanished, Theoretical calculation was conducted to disclose the structure/thermochromism correlation. [ABSTRACT FROM AUTHOR]