1,3-Bis{[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]sulfan-yl}propan-2-one.

In the distorted W-shaped mol-ecule of the title compound, C(17)H(12)N(6)O(3)S(2), a twofold axis passes through the carbonyl group. The mol-ecules stack in the crystal through π-π inter-actions [centroid-centroid distance = 3.883 Å] and weak C-H⋯N hydrogen-bonding inter-actions, forming a three-dimensional architecture.

trans-Diaqua-bis-[5-carb-oxy-4-carboxyl-ato-2-(4-pyridinio)-1H-imidazol-1-ido-κN,O]zinc(II).

In the title complex, [Zn(C(10)H(6)N(3)O(4))(2)(H(2)O)(2)], the Zn(II) atom is located on a twofold rotation axis and is coordinated by two trans-positioned N,O-bidentate and zwitterionic 5-carb-oxy-4-carboxyl-ato-2-(4-pyridinio)-1H-imidazol-1-ide (H(2)PIDC(-)) ligands and two water mol-ecules, defining a distorted octa-hedral environment. The complete solid-state structure can be described as a three-dimensional supra-molecular framework, stabilized by extensive hydrogen-bonding inter-actions involving the coordinated water mol-ecules, uncoordin-ated imidazole N atom, protonated pyridine N and carboxyl-ate O atoms of the H(2)PIDC(-) ligands.

trans-Diaqua-bis[5-carb-oxy-4-carboxyl-ato-2-(4-pyridinio)-1H-imidazol-1-ido-κN,O]iron(II).

In the title complex, [Fe(C(10)H(6)N(3)O(4))(2)(H(2)O)(2)], the Fe(II) atom is located on a twofold rotation axis and is coordinated by two trans-positioned N,O-bidentate and zwitterionic 5-carboxy-2-(pyridinium-4-yl)-1H-imidazol-1-ide-4-carboxylate H(2)PIDC(-) ligands and two water mol-ecules in a distorted environment. In the crystal packing, a three-dimensional network is constructed via hydrogen-bonding involving the water mol-ecules, uncoordinated imidazole N atom, protonated pyridine N and carboxyl-ate O atoms.

trans-Diaqua-bis[5-carb-oxy-2-(3-pyrid-yl)-1H-imidazole-4-carboxyl-ato-κN,O]iron(II).

In the title complex, [Fe(C(10)H(6)N(3)O(4))(2)(H(2)O)(2)], the Fe(II) atom is located on an inversion centre and is trans-coordinated by two N,O-bidentate 5-carb-oxy-2-(3-pyrid-yl)-1H-imidazole-4-carb-oxy-l-ate ligands and two water mol-ecules, defining a distorted octa-hedral environment. A two-dimensional network of N-H⋯O and O-H⋯O hydrogen bonds extending parallel to (110) helps to stabilize the crystal packing.

The first 1D twofold interpenetrating metal-organic network generated by 1D triple helical chains with nanosized cages.

Reaction of AgPF(6) with the asymmetric ligand 1,6-dihydro-2-methyl-6-oxo-(3,4'-bipyridine)-5-carbonitrile (1), afforded a significant silver coordination polymer {[Ag(2)(1)(3)](2).(CH(3)OH)(3).(PF(6))(4)}(n) (2) with unique 1D twofold interpenetrating metal-organic frameworks constructed by 1D triple helical chains with nanosized cages hosting counterions as guests. This compound exhibits high thermal stability and blue-shift emission with large intensity enhancement compared with that of the free ligand.

Catena-poly[[bis[5-(4-pyridyl-kappaN)-2-(2-pyridylmethylsulfanyl)-1,3,4-oxadiazole]cadmium(II)]-di-mu-thiocyanato-kappa2N:S;kappa2S:N].

The title compound, [Cd(NCS)(2)(C(13)H(10)N(4)OS)(2)](n), contains SCN(-) anions acting as end-to-end bridging ligands which utilize both S and N atoms to link cadmium(II) centers into one-dimensional double chains. The multidentate 5-(4-pyridyl)-2-(2-pyridylmethylsulfanyl)-1,3,4-oxadiazole ligands behave as monodentate terminal ligands, binding metal centers only through the N atoms of the 4-pyridyl groups. Two types of eight-membered rings are formed by two SCN(-) anions bridging Cd(II) centers, viz. planar and chair conformation, which are alternately disposed along the same chain. Finally, chains define a two-dimensional array through two different interchain pi-pi stacking interactions.

New lanthanide hybrid as clustered infinite nanotunnel with 3D Ln-O-Ln framework and (3,4)-connected net.

A series of new lanthanide hybrids [Ln3(mu-OH)4 (2,5-pydc)(2,5-Hpydc)3(H2O)4]n (Ln = Gd (1), Dy (2), Er (3), Eu (4), Sm (5), Yb (6), Y (7); 2,5-pydc=pyridine-2,5-dicarboxylate), as clustered lanthanide oxide ring tunnels with helical dodecahedral chains and fully 3D Ln-O-Ln connectivity, has been hydrothermally synthesized and characterized. The inorganic skeleton of the hybrid can be specified by the Schläfli symbol (6210)2 (64102) as a single 3D (3,4)-connected net. The luminescence properties have been studied, and the results showed that the Dy(III) (2) and Eu(III) (4) complexes exhibited sensitized luminescence in the visible region. Variable-temperature magnetic susceptibility measurements of 1-6 showed that the complexes 1-3 are nearly paramagnets, whereas the depopulation of the Stark levels in complexes 4-6 leads to a continuous decrease in mu(eff) when the sample is cooled from 300 to 2 K.