No 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.

Key indicatorsSingle-crystal X-ray study T = 293 K Mean '(C±C) = 0.003 A Ê R factor = 0.041 wR factor = 0.113 Data-to-parameter ratio = 13.7For details of how these key indicators were automatically derived from the article, see

The structure of dihydronium [catena-bis(-pyrazine-2,3-,3PZDCÞ2, is composed of polyanionic ribbons of zinc(II) ions linked by double bridging 2,3-PZDC ligand molecules. Each ligand uses an N,O bonding moiety formed by one carboxylic group [Zn-O 2.071(2) Å ; Zn-N 2.184(2) Å ] and a monodentate oxygen atom of the other carboxylate group [Zn-O 2.092(2) Å ]. Coordination around the zinc(II) ion is strongly distorted octahedral. Hydronium cations (H 3 O) 1þ link the ribbons by hydrogen bonds.

Key indicatorsSingle-crystal X-ray study T = 293 K Mean (C-C) = 0.004 Å R factor = 0.031 wR factor = 0.101 Data-to-parameter ratio = 15.8For details of how these key indicators were automatically derived from the article, see