In the title mol-ecule, C(9)H(9)NO(3)S, the bond lengths and angles fall within normal ranges. All nine ring atoms almost lie in a common plane (r.m.s. deviation 0.021 Å). In the crystal, symmetry-related mol-ecules are linked via C-H⋯O hydrogen bonds, forming a three-dimensional network.

The mol-ecule of the title compound, C(12)H(9)IN(2), is approximately planar [maximum deviation = 0.020 (5) Å] with a trans arrangement of the groups around the N=N double bond. This double bond is rotated away from the iodine substiuent.

The non-H atoms of the two independent mol-ecules in the asymmetric unit of the title compound, C(8)H(8)BrN(3)O, are planar (r.m.s. deviations = 0.015 and 0.019 Å). In the crystal, the mol-ecules are linked into a zigzag chain along the c axis by C-H⋯O hydrogen bonds.

The two mol-ecules in the asymmetric unit of the title compound, C(9)H(5)Cl(2)N, are both essentially planar (r.m.s. deviations for all non-H atoms = 0.014 and 0.026 Å). There are no close C-H⋯Cl contacts.

The Co(II) atom in the title compound, [Co(C(12)H(8)N(5))(2)(H(2)O)(4)]·2H(2)O, lies on a center of inversion and is bonded to two N-heterocycles and to four water mol-ecules in a slightly distorted octahedral coordination. The coordinated and lattice water mol-ecules inter-act with the N-heterocycles through O-H⋯N hydrogen bonds, generating a three-dimensional supra-molecular architecture.

The title mol-ecule, C(8)H(18)O(2)S(2), is disposed about a centre of inversion implying an anti-disposition of the sulfinyl-O atoms; the terminal n-propyl group has an extended conformation. The crystal packing is dominated by C-H⋯O inter-actions, which lead to the formation of supra-molecular arrays in the bc plane.

The title mol-ecule, C(12)H(8)N(2)O(4), lies on an inversion center. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds connect mol-ecules into one-dimensional chains along [11].

In the title compound, C(11)H(10)ClNO(2)·H(2)O, the organic mol-ecule is roughly planar (r.m.s. deviation = 0.074 Å). In the crystal structure, molecues are linked by O-H⋯O and O-H⋯N hydrogen bonds and weak C-H⋯π and π-π inter-actions [centroid-centroid distance = 3.578 (3) Å] consolidate the packing. A short Cl⋯O contact [3.147 (3) Å] is also observed.

There are two mol-ecules in the asymmetric unit of the title compound, C(11)H(14)N(2)O(2), which have similar conformations. In the crystal, the mol-ecules are linked by N-H⋯O hydrogen bonds, generating C(4) chains propagating in [001].