Two novel interpenetrating silver(i) coordination architectures modeled by semi-rigid tetra-pyridinate ligands

Abstract

Two novel Ag(I) coordination polymers (CPs), namely, [Ag₃(tpom)₂(NO₃)₃(H₂O)₄]_n (1) and [Ag₂(tpom2)(NO₃)₂(H₂O)₄]_n (2), (tpom = tetrakis(4-pyridyloxymethylene)methane, tpom2 = tetrakis(3-pyridyloxymethylene)methane) have been synthesized through the reaction of silver(I) nitrate and highly-connected tetra-pyridinate ligands and structurally characterized. Complex 1 exhibits the typical uninodal 3-connected four-fold interpenetrating layered hcb network with the point (Schläfli) symbol {6³} considering the tetra-pyridinate tpom ligands as tri-connected nodes, but a 2-nodal 3,4-connected self-interpenetrating 3D network with stoichiometry (3-c)₂(4-c)₂ and the point (Schläfli) symbol {6 × 10²}{6²·10⁴} considering the tetra-pyridinate tpom ligands as tetra-connected nodes. The difference between the two distinct topological structures mainly originates from the long Ag–N bond length of 2.513(3) Å in 1. In contrast, complex 2 exhibits the typical uninodal 4-connected four-fold interpenetrating 3D dia network with the point (Schläfli) symbol {6⁶}. The flexible conformation and long connection arms of the different tetra-pyridiante ligands must be responsible for the variable interpenetrating Ag(I) coordination architectures. Additionally, results about TGA and photoluminescence spectra were also discussed.