A three‐dimensional pyrazine‐2,5‐dicarboxylate CdII coordination framework with new (4,4,4)‐connected three‐nodal topology

Poly(μ₄‐pyrazine‐2,5‐dicarboxylato)cadmium(II)], Cd(C₆H₂N₂O₄)]_n or Cd(pzdc)]_n (pzdc is the pyrazine‐2,5‐dicarboxylate dianion), has been synthesized hydrothermally. The asymmetric unit consists of a Cd^II atom and two independent halves of pzdc ligands that can be expanded via inversion through the centres of the ligands so that each ligand binds to four Cd^II atoms with the same binding mode using six donor atoms. The Cd^II centre is in a distorted octahedral coordination geometry with four O‐ and two N‐atom donors from four pzdc ligands. The infinite linkage of the metal atoms and ligands forms a three‐dimensional framework with a rectangular channel which is so narrow that there is no measurable void space in the overall structure. This coordination polymer represents the first example of (4,4,4)‐connected three‐nodal framework.