Structural diversity of Ag/3-nitrophthalate coordination polymers controlled by solvent and induction agent

Abstract

Four new silver(I) coordination polymers (CPs) based on 3-nitrophthalic acid (H₂npt), [Ag₂(NH₃)₂(npt)]_n (1), [Ag₂(NH₃)(npt)]_n (2), {(NH₄)[Ag(npt)·H₂O]}_n (3) and [Ag₄(NH₃)₄(npt)₂·H₂O]_n (4), have been synthesized and structurally characterized. Compound 1 shows a 1D chain based on a binuclear Ag(I) SBU (secondary building unit). The [Ag(NH₃)₂] units are bound on the two sides of the 1D chain through the ligand-unsupported argentophilic interactions. Compound 2 is a 2D 4⁴-sql net constructed from npt ligand-bridged centrosymmetric Ag₄ rhombus SBUs. Compound 3 exhibits an anionic 2D sheet, in which the infinite chain-like [Ag₂(COO)₂]_n SBUs are observed along the b axis. In compound 4, infinite silver nets are fabricated by ligand-unsupported argentophilic interactions and the npt ligands are anchored on the net to form the 2D sheet structure. Four CPs exhibit unprecedentedly high structural diversity dependent on the solvent and induction agent. In detail, 1, 2 and 3, 4 are mainly controlled by the induction agent, but 1, 3 and 2, 4 are controlled by the solvent systems. The thermal stabilities and photoluminescence behaviours of the compounds were also discussed.