Juanhua Liu

Poly[[[diaqua­sodium]-μ3-5-carb­oxy-2-ethyl-1H-imidazole-4-carboxyl­ato-κ4 N 3,O 4:O 5:O 5] monohydrate]

In the title complex, {[Na(C7H7N2O4)(H2O)2]·H2O}n, the NaI atom exhibits a distorted octahedral geometry and is six-coordinated in an NO5 environment. The equatorial plane is defined by three O atoms and one N atom from two distinct 5-carboxy-2-ethyl-1H-imidazole-4-carboxylate (H2EIDC) ligands and one coordinated water molecule, and the apical sites are occupied by one carboxyl O atom from one H2EIDC ligand and one O atom from the other coordinated water molecule. The NaI atoms are linked by H2EIDC ligands, generating an infinite double chain along the a axis. These chains are further connected via O—H⋯O and N—H⋯O hydrogen bonds into a three-dimensional supramolecular network.

Poly[diaqua­(μ3-1H-benzimidazole-5,6-dicarboxyl­ato-κ4N3:O5,O6:O6′)magnesium(II)]

In the title complex, [Mg(C9H4N2O4)(H2O)2]n, the MgII atom is six-coordinated by one N and three O atoms from three different 1H-benzimidazole-5,6-dicarboxylate ligands and two O atoms from two water molecules, forming a slightly distorted octahedral geometry. The ligand links the MgII centres into a three-dimensional network. Extensive N—H⋯O and O—H⋯O hydrogen bonds exist between the ligands and water molecules, stabilizing the crystal structure.

catena-Poly[[diaqua­calcium(II)]-bis­(μ-quinoline-3-carboxyl­ato)]

In the title complex, [Ca(C10H6NO2)2(H2O)2]n, the CaII ion is eight-coordinated by six carboxylate O atoms from four separate quinoline-3-carboxylate ligands, two of which are bidentate chelate and two bridging, and two water molecules in a distorted square-antiprismatic geometry. The bridging groups form a polymeric chain substructure extending along the c axis, the chains being connected by coordinated-water O—H⋯N and O—H⋯Ocarboxylate hydrogen bonds into a three-dimensional framework structure.

Poly[[diaqua­(μ4-1H-benzimidazole-5,6-dicarboxyl­ato)strontium] monohydrate]

Each of the carboxylate –CO2 fragments of the dianion ligand in the title compound, {[Sr(C9H4N2O4)(H2O)2]·H2O}n, chelates to a SrII atom and at the same time, one of the two O atoms coordinates to a third SrII atom. The μ4-bridging mode of the dianion generates a square-grid layer motif; adjacent layers are connected by O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds, forming a three-dimensional network. The eight-coordinate Sr atom exists in a distorted square-antiprismatic geometry. The crystal studied was a non-merohedral twin with a minor twin component of 24%.

2-Ethyl-1H-imidazole-4-carboxyl-ate monohydrate.

In the title compound, C7H8N2O4·H2O, the imidazole N atom is protonated and one of the carboxylate groups is deprontonated, forming a zwitterion. The two carboxyl groups are are approximately coplanar with the imidazole ring [O—C—C—C torsion angles = −176.8 (2) and 2.9 (4)° for one group and −4.6 (3) and 176.4 (2)° for the other] and have an intramolecular O—H⋯O hydrogen bond between them. The water molecule is linked to the organic molecules via an N—H⋯O hydrogen bonds. Intermolecular O—H⋯O and N—H⋯O hydrogen bonds are found in the crystal structure.