Monomeric molecules in the crystal structures of magnesium(II) and zinc(II) complexes with imidazole-4-carboxylate and water ligands

Abstract

Magnesiumimidazolate: trans-diaquabis(imidazole-4-carboxylato-2 N,O)-magnesium(II) Mg(C 4 H 3 N 2 O 2 ) 2 (H 2 O) 2 crystallizes in the monoclinic system (space group P2 1 /c). The structure is composed of monomeric molecules, each containing a Mg(II) ion located at the inversion centre and chelated by two imidazole-4-carboxylate ligand molecules via their N,O bonding moieties (Mg-N 2.193(2)Å 0 , Mg-O 2.070(2)Å 0 ) and two water oxygen atoms (Mg-O 2.063(2)Å 0 . A fairly regular octahedron with water oxygen atoms at the apical positions is formed. The monomers are kept together by hydrogen bonds. Triclinic unit cell (space group P 1) of zinc imidazolate: [trans-diaquabis(imidazole-4-carboxylato-2 N,O)-zinc(II)] [monoaquabis(imidazole-4-carboxylato-N,O)-zinc(II)] trihydrate [Zn(C 4 H 3 N 2 O 2 ) 2 (H 2 O) 2 ][Zn(C 4 H 3 N 2 O 2 ) 2 (H 2 O)] Á 3H 2 O contains two monomeric complex molecules in which the Zn(II) ion is octahedrally coordinated by two trans ligand molecules and two water oxygen atoms. The unit cell also contains two monomeric complex molecules in which the Zn(II) ion is pentacoordinate with two ligand molecules and one water oxygen atom. Six solvation water molecules complete the content of the unit cell. Mean bond distances in the pentacoordinated Zn(II) polyhedron are: 2.101(2)Å 0 (Zn-O), 2.040(2)Å 0 (Zn-N) and 2.002(3)Å 0 (Zn-O water ). An extended network of hydrogen bonds is responsible for the stability of the structure.

Coordination Chemistry of Thiazole‐Based Ligands: New Complexes Generating 3D Hydrogen‐Bonded Architectures

“…[15] Although the final pH of the solution preserves the ligand from undesired decarboxylation, the stable acetate bridges in the Cu (Tables S3 and S4) are similar to those reported for other zinc(II) complexes of the general formula [Zn(L) 2 [16] imidazole-4-carboxylate, [17] or 4-(carboxylato)-imidazole-5-carboxylic acid]. [18] In these examples the imidazole-and triazole-based ligands have an identical κ 2 -N,Ochelating coordination mode, the resulting complexes being isostructural with the thiazole-based analogue 1.…”

Cytotoxic and Antimicrobial Activities of Cu(II), Co(II), Pt(II) and Zn(II) Complexes with N,O‐Chelating Heterocyclic Carboxylates

“…For example, the reaction between benzimidazole-2-carboxylic acid and CuCl 2 in both a 1:1 and 2:1 ratio led to mixtures of products that could not be separated and characterized. Likewise, a complex between Zn(II) and 1H-imidazole-4-carboxylic acid has been reported recently by X-ray crystallography to be a transconfigured bis-imidazole-4-carboxylate chelate [35] but we were unable to obtain this compound in pure enough form for biological testing.…”

Structure of Sonic Hedgehog protein in complex with zinc(II) and magnesium(II) reveals ion-coordination plasticity relevant to peptide drug design

“…The presence of mixed-occupancy Zn 2+ /Mg 2+ at the Zn 2+ site of Shh-N best explains the observed octahedral coordination geometry and electron density. Precedents for octahedral Mg 2+ coordinated by carboxylate and imidazole ligands come from small-molecule structures (Gryz et al, 2007;Stadie et al, 2007;Liu & Liu, 2010;Ye et al, 1998;Srinivasan et al, 2007). Likewise, small-molecule examples are available for octahedral Zn 2+ coordination arising from two imidazole and two carboxylate ligands (Carballo et al, 2004;Li et al, 2014;Shimizu et al, 2004).…”