Silver(I)-ethynide supramolecular synthons in the assembly of pi-pi stacked infinite columns

摘要

In a series of four silver(I) complexes containing nitrate and ethynide ligands attached to different aromatic rings, namely, [Ag-2(m-C CC6H4C C)]center dot 5AgNO(3) center dot 3H(2)O (1), 2[(AgC C)(2)-2,3-C4H2S]center dot 10AgNO(3) (2), [(AgC C)-3-py]center dot 3AgNO(3) (3), and 2[(AgC C)-2-pyz] center dot 6AgNO(3) center dot 3H(2)O (4) (py = pyridine; pyz = pyrazine), intermolecular pi-pi interaction dominates the assembly of supramolecular synthons Ag4 subset of C C-R-C C superset of Ag-4 and R-C C superset of Ag-4 to give infinite columnar structures exhibiting distinct pi-pi stacking modes. The decrease in aromaticity of the ring moieties in 1, 3, and 4 is accompanied by weakened a-a stacking, transforming from the parallel face-to-face mode in 1, through a displaced stacked arrangement in 3, to the edge-to-face contact in 4. Replacement of one ethynide moiety of m-phenylenediethynide ligand in I by nitrogen coordination sites on the aromatic ring in 3 and 4 was found to have a limited effect on interrupting the whole pi-pi stacking infinite column.