Crystal structure of a helical silver(I) coordination polymer based on an unsymmetrical dipyridyl ligand: catena-poly[[silver(I)-μ-N-(pyridin-4-ylmeth-yl)pyridine-3-amine-κ (2) N:N'] tetra-fluorido-borate methanol hemisolvate].

The asymmetric unit of the title compound, {[AgL]·BF4·0.5CH3OH} n , L = N-(pyridin-4-ylmeth-yl)pyridine-3-amine, C11H11N3, contains one Ag(I) ion, one ligand L, one tetra-fluorido-borate anion disordered over two orientations in a 0.669 (13):0.331 (13) ratio and one half of a methanol solvent mol-ecule situated on an inversion center. Each Ag(I) ion is coordinated by two N atoms from two L ligands in a distorted linear geometry [N-Ag-N = 174.70 (19)°]. Each L ligand bridges two Ag(I) ions, thus forming polymeric helical chains propagating in [010]. In the crystal, Ag⋯Ag [3.3369 (10) Å] and π-π inter-actions between the aromatic rings [centroid-to-centroid distance = 3.676 (4) Å] link these chains into layers parallel to (10-1). Ag⋯F and weak N(C)-H⋯F inter-actions further consolidate the crystal packing.