Multidimensional Snowflake‐shaped (3, 9)‐connected Metal‐Organic Frameworks Composed of Ni₃(μ₃‐O) Building Blocks and Symmetry Ligand Pyridine‐3,5‐dicarboxylic Acid

A metal‐organic polymer [Ni 3 ( μ 3 ‐O)(PDB) 3 ]·H 2 O ( 1 ) (PDB = pyridine‐3,5‐dicarboxylate), with antiferromagnetic interactions between the adjacent Ni atoms, containing trinuclear μ 3 ‐oxo‐bridged metal units Ni 3 ( μ 3 ‐O) have been synthesized by hydrothermal reaction of the achiral building blocks pyridine‐3,5‐dicarboxylate (3,5‐PDB) and Ni(NO 3 ) 2 ·4H 2 O. Compound 1 shows a high symmetry three‐dimensional snowflake‐shaped (3, 9)‐connected topology structures in which μ 3 ‐oxo mixed‐valence Ni 3 O(CO 2 ) 6 clusters act as nine‐connected nodes and PDB ligands act as three‐connected nodes.