Pyrazine-2,3-Carboxylate Based Ag⁺ Homometallic and Ln³⁺–Ag⁺ Heterometallic Coordination Frameworks: Synthesis, Structures, and Magnetic Properties

One Ag⁺ homometallic complex [Ag₄(pzdc)₂]·H₂O (<b>1</b>), and five Ln–Ag heterometallic complexes, namely, [Gd₂Ag₆(pzdc)₆(H₂O)₉]·8H₂O (<b>2</b>) and [LnAg­(pzdc)₂(H₂O)₂]·2H₂O [Ln = Tb (<b>3</b>), Dy (<b>4</b>), Ho (<b>5</b>), Er (<b>6</b>)] based on pyrazine-2,3-dicarboxylate (pzdc^2–) have been synthesized under room temperature. Complex <b>1</b> exhibits 3D metal–organic framework by Ag2 ions connecting 1D square columns consisting of Ag1 ions and pzdc^2– ligands, possessing a unique trinodal net with {4²·6}­{4³}­{4⁵·6⁴·8³·10³} topology. Complex <b>2</b> displays a 3D heterometal–organic framework with a novel 12-nodal topological net constructed by Gd1 ions linking the adjacent Ag-pzdc^2– anion layers. Complexes <b>3</b>–<b>6</b> are isostructural 2D Ln–Ag heterometallic coordination frameworks featuring uninodal 4-connected net with {4⁴·6²} topology. Magnetic analyses suggest that complexes <b>4</b> and <b>6</b> exhibit field-dependent slow magnetic relaxation, and complex <b>6</b> represents the first slow magnetic relaxation behavior existing in Er³⁺-based 2D heterometallic coordination framework