Assembly of three-dimensional networks based upon silver-ethynide complexes bearing pyridyl and carboxylate groups

Two ligands with different geometries have been prepared to synthesize new silver-ethynide complexes bearing pyridyl and carboxylate groups. Reactions of 5-ethynylnicotinic acid (H(2)L1) and 5-ethynylpicolinic acid (H(2)L2) with silver nitrate afforded [Ag(2)(L1)·AgNO(3)](n) (1) and {[Ag(12)(L2)(6)·12AgNO(3)]·5H(2)O}(n) (2), respectively. Crystallographic studies revealed that in 1, the L1 ligands connect linear silver chains to form a 2D layer through silver-ethynide interactions and Ag-carboxylate coordination bonds, and subsequently the layers are further linked through Ag-N(pyridyl) coordination bonds to generate a 3D network; however in 2, the L2 ligand interacts with Ag(8) units through Ag-N, Ag-O coordination bonds, silver-ethynide interactions and π-π stacking directly to assemble a 3D network. In the solid state, both complexes are luminescent at room temperature, assigned as the intraligand n-π* and π-π* transitions.