Novel supramolecular synthon in crystal engineering: ionic complexes of 4,4′-bipyridine and 1,2-bis(2-pyridyl)ethylene with 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone

Abstract

4,4′-Bipyridine (BPY) and 1,2-bis(2-pyridyl)ethylene (2-PDE) form bifurcated hydrogen bonds with 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid, 2H-CLA) to afford [BPY-2H]²⁺[CLA]^2– 1 and [2-PDE-2H]²⁺[CLA]^2– 2; their crystal structures exhibit a new type supramolecular synthon and links as molecular chains and zigzag tapes, respectively.