Syntheses and crystal structures of two new silver-organic frameworks based on N-pyrazinesfulfonyl-glycine: weak Ag...O/N interaction affecting the coordination geometry

Two new metal-organic frameworks, namely, [Ag-2(L)](n) (1) and {[Ag-2.5(L)(bpy)(2)]center dot(NO3)(0.5)center dot(H2O)(4.5)}(n) (2), where H2L = N-pyrazinesulfonyl-glycine and bpy = 4,4'-bipyridine, have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental analysis. X-ray diffraction crystallographic analyses indicate that 1 displays a silver carboxylate-sulfonamide layer structure containing an uncommon heptanuclear [Ag-7] cluster wherein four silver(I) atoms form an Ag-4 plane with in a three-connected (6, 3) net. The molecular structure of 2 has three crystallographically independent two-coordinate Ag centers with an intersecting Ag-bpy chain structure in a six-connected (3, 6) or a four-connected (4, 4) topology. The L2- ligand serves as a mu(7)-(eta(2)-O,N),(eta(2)- O', N'), O, O ", O"', N, N " ligand in 1 and as a mu(3)-(eta(2) -O, N), N, O' ligand in 2. In the crystal, a 3D supramolecular architecture is formed by coordinative bonding in 1, but through O-H center dot center dot center dot O bonding as well as pi center dot center dot center dot pi stacking in 2. The two compounds show a combination of coordinative bonds, ligand-supported Ag center dot center dot center dot Ag interactions and weak Ag center dot center dot center dot O/N coordinative interactions in the solid state.