Jian-Rong Su

Bis(μ-2,4-dihy­droxy­benzoato-κ2O:O′)bis­[aqua­(2,4-dihy­droxy­benzoato-κO)(1,10-phenanthroline-κ2N,N′)cadmium(II)]

In the title centrosymmetric dimeric CdII complex, [Cd2(C7H5O4)4(C12H8N2)2(H2O)2], the CdII cation is coordinated by a bidentate phenanthroline (phen) ligand, three dihydroxybenzoate (dhba) anions and one water molecule in a distorted CdN2O4 octahedral geometry. Among the dhba anions, two anions bridge two CdII cations to form the dimeric complex with significant different Cd—O bond distances of 2.2215 (19) and 2.406 (2) Å. The centroid–centroid distance of 3.4615 (19) Å between two nearly parallel benzene rings of the dhba and phen ligands coordinating to the same CdII cation indicates the existence of intramolecular π–π stacking in the complex. Extensive O—H⋯O hydrogen bonding and intermolecular weak C—H⋯O hydrogen bonding help to stabilize the crystal structure. One hydroxy group of the monodentate dhba ligand is disordered over two sites with a site-occupancy ratio of 0.9:0.1.

Aqua(3-hydroxybenzoato-κO)bis(1,10-phenanthroline-κ2N,N′)cobalt(II) 3-hydroxybenzoate pentahydrate

The crystal structure of the title compound, [Co(C(7)H(5)O(3))(C(12)H(8)N(2))(2)(H(2)O)](C(7)H(5)O(3))·5H(2)O, consists of Co(II) complex cations, uncoordinated hydroxy-benzoate anions and uncoord-inated water mol-ecules. The Co(II) ion is coordinated by two phenanthroline ligands, a water mol-ecule and a 3-hydroxy-benzoate anion, and displays a distorted octa-hedral geometry. π-π stacking is observed between parallel phenanthroline ligands, the face-to-face separations being 3.454 (19) and 3.435 (7) Å. An extensive hydrogen-bonding network helps to stabilize the crystal structure. The hydroxybenzoate ligand is disordered over two positions, with site occupancy factors 0.6 and 0.4. One solvent water molecule is also disordered over two positions, with site occupancy factors 0.6 and 0.4.

catena-Poly[[bis­(1H-benzimidazole-κN3)cobalt(II)]-μ-terephthalato-κ3O1,O1′:O4]

In the title compound, [Co(C8H4O4)(C7H6N2)2]n, the terephthalate dianions bridge CoII ions through terminal carboxyl groups to form polymeric complex chains; one carboxyl group coordinates in a monodentate manner and the other chelates to the Co atom. Two benzimidazole ligands also coordinate to the Co atom to complete a distorted trigonal–bipyramidal coordination geometry. The crystal packing is stabilized by N—H⋯O hydrogen bonds and π–π stacking involving the benzimidazole ligands, with a face-to-face separation of 3.454 (11) A.