Effect of synthetic conditions on the structures of silver(I)-hexamethylenetetramine coordination polymers: crystal structures of two three-dimensional frameworks featuring new topological motifs

Two novel coordination complexes, [Ag₃(μ₄-hmt)₂(μ-ssa)(H₂O)](NO₃)·3H₂O 1, and [Ag₈(μ₃-hmt)₂(μ₄-hmt)₂(μ-pma)₂(μ-H₂O)₃]·18H₂O 2 (hmt=hexamethylenetetramine, ssa=sulfosalicylate and pma=1,2,4,5-benzenetetracarboxylate), have been prepared and structurally characterized. Crystal data: 1 C₁₉H₃₃Ag₃N₉O₁₃S, orthorhombic, Pna2₁, a=20.483(7) Å, b=21.890(1) Å, c=6.493(2) Å, V=2911.3(13) Å³, Z=4; 2 C₄₄H₉₄Ag₈N₁₆O₃₇, monoclinic, C2/c, a=32.099(10) Å, b=12.916(3) Å, c=21.431(8) Å, β=126.74(1)°, V=7120(4) Å³, Z=4. Both complexes exhibit unprecedented and different topological motifs of Ag-hmt networks. Complex 1 is a novel three-dimensional cationic network with two types of channels, in which the larger one is the largest one in Ag-hmt networks; while 2 is a three-dimensional network with cylindrical channels, consisting of mixed μ₃- and μ₄-hmt ligands. The results demonstrate that under different synthetic conditions, such as the presence of multiple small counter anions or different pH values, different Ag-hmt linkages may be formed to generate new three-dimensional networks.