3D H-bonding networks self-assembly from pyridinium derivatives and bis(maleonitriledithiolato)zincate(II)

The two ion-pair complexes, [pyH]₂[Zn(mnt)₂] (1) and [4,4′-bipyH₂]-[Zn(mnt)₂] (2), were synthesized, where mnt^2- denotes maleonitriledithiolate, and [pyH]⁺, [4,4′-bipyH₂]²⁺ represent pyridinium and diprotonated 4,4′-bipyridinium, respectively. Their single crystal structures show that there are strong bifurcated H-bonding interactions between the cations of the pyridinium derivative and the [Zn(mnt)₂] ^2- anions in both 1 and 2. The bifurcated H-bonding interactions between the N-H of the pyridiniums and the CN groups of the mnt^2- ligands give rise to a 2D layered H-bonding network, the adjacent layers come together in such way as mutual embrace to give a tight pack, thus 2D hydrogen-bonding sheets further develop into 3D H-bonding networks through weak C-H⋯S and π⋯π stacking interactions in 1. As for 2, the cations and anions connect into several types of H-bonding macrorings ([2 + 2], [3 + 3] and [4 + 4]), these H-bonding macrorings fuse to extend into 2D layered structure, the interpenetration between [3 + 3] and [4 + 4] type H-bonding macrorings in the adjacent layers give further rise to novel 3D extended H-bonding networks, in which there are clearly parallel stacks of cations and the chelate rings of anions.