American Chemical Society
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Molecular Cage and 1-D Coordination Architectures Assembled from Silver(I) and Dithioether Ligands with Bulky Anthrene Spacers:  Syntheses, Crystal Structures, and Emission Properties

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journal contribution
posted on 2006-03-01, 00:00 authored by Tong-Liang Hu, Jian-Rong Li, Ya-Bo Xie, Xian-He Bu
A series of dithioether ligands with bulky anthrene spacers, 9,10-bis[(ethylthio)methyl]anthracene (L), 9,10-bis[(n-propylthio)methyl]anthracene (L), 9,10-bis[(n-butylthio)methyl]anthracene (L), and 9,10-bis[(tert-butylthio)methyl]anthracene (L), have been designed and synthesized. The reactions of these ligands with AgX (X = NO3-, ClO4-, PF6-) lead to the formation of six new metal−organic coordination architectures, [Ag4(L1)2(NO3)4](CHCl3)2 (1), [Ag4(L2)2(NO3)4](CHCl3)2 (2), [Ag4(L3)2(NO3)4] (3), {[AgL2(CH3CN)](ClO4)} (4), {[AgL4(NO3)]2(CH3CN)} (5), and {[AgL4](PF6)} (6), which have been characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. Single-crystal X-ray analyses show that complexes 13 possess novel tetranuclear molecular cage structures, while 46 have chain structures. In 13, the S atoms of the ligands take a μ2-S bridging coordination mode to link AgI ions; thus four S atoms of two ligands link four AgI ions to form a tetranuclear cage. The differences of ligand terminal groups in L1, L2, and L3 do not greatly influence the structures of their complexes. However, the changes of the terminal groups cause subtle differences in the coordination geometry of the AgI centers, the number of solvent molecules encapsulated in the space among adjacent tetranuclear moieties, and the packing mode of the tetranuclear units. Complex 5, whose ligand bears larger tert-butyl terminal groups, is a one-dimensional (1-D) structure instead of a tetranuclear cage. In addition, the structural differences of 2 and 4 (5 and 6) may contribute to the relatively stronger coordination ability of NO3- than that of ClO4- (or PF6-). These results indicate that the terminal groups of the ligands and the counteranions may play important roles in governing the structural topologies of such metal−organic coordination architectures. Furthermore, complexes 16 also display strong blue emissions in the solid state at room temperature.