Supramolecular Architecture via Self-Complementary Amide Hydrogen Bonding in [Ag(pia)₂](NO₃)·H₂O: Synthesis, Thermal and Structural Studies

Abstract

The synthesis, thermal and spectral characterization and crystal structure of silver(I) complex with picolinamide, [Ag(C₆H₆N₂O)₂](NO₃)·H₂O, are reported. The silver(I) atom is chelated by two picolinamide (pia) ligands in approximately square planar geometry. The distortion within the coordination environment is mainly imposed by formation of the chelate rings, but it is also observed in two longer (Ag–O) and two shorter (Ag–N) bond lengths. The compound crystallizes in the triclinic space group $P\bar{1}$ with a = 7.1265(2) Å, b = 8.9157(4) Å, c = 12.9527(4) Å, α = 83.934(3)°, β = 86.094(2)°, γ = 67.023(3)° and Z = 2. Cationic complexes are linked through amide–amide hydrogen bonds of ‘head-to-head’ R ²₂ (8) motif leading to infinite chains, while nitrate anions and H₂O molecules act only as a cross-link between such four symmetry related cationic chains via hydrogen bonds forming 2D supramolecular double sheets. Therefore, the ‘head-to-head’ amide interactions in [Ag(C₆H₆N₂O)₂](NO₃)·H₂O are robust enough to accommodate the usually disruptive NO₃ ⁻ anion and H₂O molecule and could be regarded as a tool for controlling the assembly of this silver complex.

Index Abstract

Square planar silver(I) complex with picolinamide, [Ag(pia)₂]⁺, propagates through self-complementary amide hydrogen bonds, forming a supramolecular chain structure. The amide–amide interactions are robust enough to accommodate the usually disruptive NO ⁻₃ anion and H₂O molecule.