Multidimensional Networks of π-Conjugated Oligomers: Crystal Structures of 4,4‘:2‘,2‘ ‘:4‘ ‘,4‘ ‘‘-Quaterimidazole in Hydrate, Protonated Salt, and Dinucleic Copper Complexes

Hydrogen-bonded networks of 4,4‘:2‘,2‘ ‘:4‘ ‘,4‘ ‘‘-quaterimidazole, a new molecular building block for supramolecular
assemblies based on π-conjugated oligomers, are investigated in tetrahydrate, hydroiodic acid salt, and dinucleic copper complexes.
We emphasize that multidimensional networks are constructed by taking advantage of a two-directional nature of hydrogen-bonding
interactions inherent in the imidazole-ring system. In the crystal structure of the tetrahydrate, hydrogen-bonding interactions through
water molecules construct a three-dimensional network including a π-stacking columnar structure. The hydroiodic acid salt forms
a one-dimensional tape-like structure by double hydrogen bondings across the iodide anions and solvent molecules. The dicopper
complex of quaterimidazole exhibits intra- and intermolecular hydrogen bondings to construct a one-dimensional chain by N−H···O···H−N hydrogen bonding through water molecules. These hydrogen-bonding modes of the quaterimidazole system are discussed
in view of a structural relationship with 2,2‘- and 4,4‘-biimidazole systems.