Novel topological supramolecular architectures based on partially protonated butane-1,2,3,4-tetracarboxylato complexes: Synthesis, structures and magnetic properties

Abstract This work presents three supramolecular complexes with partially protonated butane-1,2,3,4-tetracarboxylato ligand [Ni 2 (phen) 4 (H 2 BUTC)]·2H 3 BUTC·6H 2 O 1 , [Cu(phen) 2 (H 2 BUTC)]·5H 2 O 2 and [Cu(bpy) 2 (H(HBUTC) 2/2 )]·H 2 O 3 (H 4 BUTC = butane-1,2,3,4-tetracarboxylic acid, phen = 1,10-phenanthroline and bpy = 2,2′-bipydine). Compound 1 represents a first example of coordination compounds with the tri-protonated butane-1,2,3,4-tetracarboxylate anion. The 2D cation supramolecular layer could be described as a 2D 3-connected honeycomb network, and the 3D anion supramolecular architecture can be considered to be a planar and tetrahedral binodal Mog network. The 2D cation layer inserts into the 3D anionic supramolecular architecture to form the rare interpenetrating network. In 2 , the Cu(phen) 2 (H 2 BUTC) units are linked by hydrogen bonding interactions to a 1D double-chain, which are engaged in π–π stacking interactions leading to (3,4)-connected 3D supramolecular architecture with the Schlafli symbol of (4 2 · 6 · 8 2 · 10)(8 2 · 10). The compound 3 exhibits a rare 1D symmetric-hydrogen-bond-chain, the resulting chains are via hydrogen bonding and π–π stacking interactions to 3D (3,4)-connected network with the Schlafli symbol of (6 3 )(6 5 ⋅ 8). The magnetic susceptibility data of 1 – 3 all obey the Curie–Weiss law, and the variable temperature magnetic characterizations on 1 – 3 suggest weak antiferromagnetic coupling exchange.