Poly[[diaqua-bis(µ(2)-isonicotinato-κN:O)bis-(µ(3)-isonicotinato-κN:O:O')neodymium(III)disilver(I)] nitrate monohydrate].

In the title complex, {[Ag(2)Nd(C(6)H(4)NO(2))(4)(H(2)O)(2)]NO(3)·H(2)O}(n), the Nd(III) ion is coordinated by eight O atoms from six isonicotinate ligands and two water mol-ecules in a distorted square anti-prismatic geometry. Each Ag(I) ion is coordinated by two N atoms from two different isonicotinate ligands. The crystal structure exhibits a two-dimensional heterometallic polymeric layer. O-H⋯O hydrogen bonds involving the coordinated and uncoordinated water mol-ecules and intra-layer π-π inter-actions between the pyridine rings [centroid-centroid distances = 3.571 (2) and 3.569 (2) Å] are observed. Each layer inter-acts with two neighboring ones via Ag⋯O(H(2)O) contacts and inter-layer π-π inter-actions [centroid-centroid distances = 3.479 (3) to 3.530 (3) Å], leading to a three-dimensional supra-molecular network.

Poly[diaqua-bis(µ(3)-1H-benzimidazole-5,6-dicarboxyl-ato-κN:O,O:O)bis-(µ(2)-1H,3H-benzimidazolium-5,6-dicarboxyl-ato-κO,O:O)digadolinium(III)].

In the title complex, [Gd(2)(C(9)H(4)N(2)O(4))(2)(C(9)H(5)N(2)O(4))(2)(H(2)O)(2)](n), two of the benzimidazole-5,6-dicarboxyl-ate ligands are pro-ton-ated at the imidazole groups. Each Gd(III) ion is coordinated by six O atoms and one N atom from five ligands and one water mol-ecule, displaying a distorted bicapped trigonal-prismatic geometry. The Gd(III) ions are linked by the carboxyl-ate groups and imidazole N atoms, forming a layer parallel to (001). These layers are further connected by O-H⋯O and N-H⋯O hydrogen bonds into a three-dimensional supra-molecular network.

Poly[[aqua-(µ(2)-oxalato)(µ(2)-2-oxido-pyridinium-3-carboxylato)dysprosium(III)] monohydrate].

In the title complex, {[Dy(C(6)H(4)NO(3))(C(2)O(4))(H(2)O)]·H(2)O}(n), the Dy(III) ion is coordinated by seven O atoms from two 2-oxidopyridinium-3-carboxylate ligands, two oxalate ligands and one water mol-ecule, displaying a distorted bicapped trigonal-prismatic geometry. The carboxyl-ate groups of the 2-oxidopyridinium-3-carboxylate and oxalate ligands link dysprosium metal centres, forming layers parallel to (100). These layers are further connected by inter-molecular O-H⋯O hydrogen-bonding inter-actions involving the coordin-ated water mol-ecules, forming a three-dimensional supra-molecular network. The uncoordinated water mol-ecule is involved in N-H⋯O and O-H⋯O hydrogen-bonding inter-actions within the layer.

Hemi(4,4'-bipyridinium) hexa-fluorido-phosphate bis-(4-amino-benzoic acid) 4,4'-bipyridine monohydrate.

In the title compound, 0.5C(10)H(10)N(2) (2+)·PF(6) (-)·C(10)H(8)N(2)·2C(7)H(7)NO(2)·H(2)O, the cation is located on a center of symmetry. The crystal structure is determined by a complex three-dimensional network of inter-molecular O-H⋯O, O-H⋯N, N-H⋯N and N-H⋯F hydrogen bonds. π-π stacking inter-actions between neighboring pyridyl rings are also present; the centroid-centroid distance is 3.643 (5) Å. The hexa-fluoridophosphate anion is disordered over two positions with site-occupancy factors of ca 0.6 and 0.4.