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The structure of the title compound, [Zn(4)(C(40)H(24)N(8))(4)]·8C(3)H(7)NO·3H(2)O, has been redetermined at 100 K. The redetermination is of significantly higher precision and gives further insight into the disorder of pyridyl groups and solvent mol-ecules. The mol-ecules of (5,10,15,20-tetra-4-pyridyl-porphyrinato)zinc(II) (ZnTPyP) form homomolecular cyclic tetra-mers by coordination of a peripheral pyridyl group to the central Zn atom of an adjacent symmetry-related mol-ecule. The tetra-mer so formed exhibits mol-ecular S(4) symmetry and is located about a crystallographic fourfold rotoinversion axis. Severely disordered dimethyl-formamide and water mol-ecules are present in the crystal, the contributions of which were omitted from refinement. Inter-molecular C-H⋯N hydrogen bonding is observed.

The crystal structure of β-cyclo-dextrin, C(42)H(70)O(35)·10.41H(2)O, consists of truncated cone-shaped β-cyclo-dextrin mol-ecules that are herringbone packed. The primary hydr-oxy groups form an intra-molecular hydrogen-bonded array. The semipolar cavity of the cyclo-dextrin host is filled with water mol-ecules, which show partial occupancy and disorder.

In the title compound, [Ni(NO(3))(2)(C(6)H(15)OP)(2)], the Ni(II) ion, lying on a crystallographic twofold axis, adopts a distorted octa-hedral coordination, consisting of O-donor atoms of two symmetry-related triethyl-phospine oxide and two bidentate nitrate ligands.

The crystal structure of the title compound, [Cu(2)Cl(4)(C(10)H(8)N(2)O(2)S)(2)(H(2)O)(2)], comprises neutral centrosymmetric μ-chloride-bridged dinuclear units. Each Cu(II) ion is penta-coordinated by three chloride ligands, a pyridine N-oxide O atom and a water mol-ecule. Intra- and inter-molecular O-H⋯O hydrogen bonds occur between the coordinated water mol-ecules and the uncoordinated and coordinated pyridine N-oxide groups of the 2,2'-thio-bis(pyridine N-oxide) ligands, respectively.

The formula unit of the title compound, 2C(6)H(7)N(2)O(+)·C(2)O(4) (2-), comprises two symmetry-equivalent 4-(hydroxy-imino-meth-yl)-pyridinium cations on general positions, linked through hydrogen bonding via an oxalate anion that resides on a crystallographic centre of symmetry. The crystal structure consists of infinite chains of cations and oxalate anions directed by O-H⋯O and multicentre N-H⋯O inter-molecular hydrogen-bonding inter-actions.