4-(Imidazol-1-yl)benzoic acid.

In the title mol-ecule, C(10)H(8)N(2)O(2), the imidazole and benzene rings form a dihedral angle of 14.5 (1)°. In the crystal, inter-molecular O-H⋯N hydrogen bonds link the mol-ecules into chains extending in [01], which are further linked into sheets parallel to (102) through weak C-H⋯O inter-actions.

1-(4-Carb-oxy-phen-yl)-1H-imidazol-3-ium chloride dihydrate.

In the crystal structure of the title compound, C(10)H(9)N(2)O(2) (+)·Cl(-)·2H(2)O, the components are linked by O-H⋯O, N-H⋯O, O-H⋯Cl and N-H⋯Cl hydrogen bonds. In the cation, the imidazole ring is oriented at a dihedral angle of 13.67 (17)° with respect to the benzene ring.

9-Ethyl-3,6-bis-(5-iodo-2-thien-yl)-9H-carbazole.

In the title compound, C(22)H(15)I(2)NS(2), the two thio-phene rings are twisted out of the plane of the central pyrrole ring, making dihedral angles of 32.4 (2)° and 9.8 (2).

Various unique coordination patterns of Hg and DFT calculations to determine the formation of a 3-D supramoleculer framework by covalent and noncovalent interactions.

By combining a large pi-conjugated bidentate ligand L: 3,6-dipyrazole-N-ethylcarbazole with HgI(2), an extraordinary supramolecular coordination polymer, [Hg(4)L(2)I(8)](infinity), has been prepared. The crystal structures of the ligand and its coordination polymer were determined by X-ray crystallography, which shows three varied coordination modes especially the rare asymmetric quadruply bridged trinuclear moieties in [Hg(4)L(2)I(8)](infinity). Density functional theory (DFT) calculations (ADF) performed on model dimers show the roles of covalent and noncovalent interactions in establishing the three-dimensional architecture.

9-Hexyl-3-iodo-9H-carbazole.

In the title mol-ecule, C(18)H(20)IN, the tricyclic carbazole system is essentially planar with the two outer rings forming a dihedral angle of 0.43 (8)°. The crystal packing exhibits no short inter-molecular contacts.