Bis[(2-quinol-yl)methane-diol-κN,O](sulfato-κO)copper(II) dihydrate.

In the title compound, [Cu(SO(4))(C(10)H(9)NO(2))(2)]·2H(2)O, the Cu(II) ion is chelated by two (2-quinol-yl)methane-diol ligands and coordinated by a monodentate sulfate ligand in a distorted trigonal-bipyramidal environment, with O atoms occupying the equatorial sites and N atoms in the axial sites. The dihedral angle between the two essentially planar quinoline ring systems is 45.02 (9)°. In the crystal structure, an extensive O-H⋯O hydrogen-bonding network forms layers parallel to the ab plane.

4-Amino-3,5-di-2-pyridyl-4H-1,2,4-triazole.

In the crystal structure of the title compound, C(12)H(10)N(6), the mol-ecules deviate slightly from planarity. The plane of the central triazole ring makes angles of 6.13 (9) and 3.28 (10)° with the pyridyl ring planes. Intra-molecular N-H⋯N inter-actions form six-membered closed rings. The crystal packing also shows weak C-H⋯π and C-H⋯N inter-actions.

Pyromellitic acid-sarcosine (1/2).

The title compound, C(10)H(6)O(8)·2C(3)H(7)NO(2), crystallizes as an adduct with the acid and amino acid mol-ecules in their neutral forms. The asymmetric unit contains one half of a centrosymmetric pyromellitic acid mol-ecule and one sarcosine mol-ecule. The sarcosine has the amine group protonated and the carboxyl group deprotonated, as is usual for amino acids (zwitterionic form). The pyromellitic acid mol-ecules retain the four carboxyl H atoms with the carboxyl groups rotated out of the ring plane [O-C-C-C torsion angles = 24.1 (3) and 61.6 (2)°]. There is a three-dimensional hydrogen-bond network linking the mol-ecules.

(Benzoato-κO,O')(quinoline-2-carboxyl-ato-κN,O)(quinoline-2-carboxylic acid-κN,O)copper(II).

The crystal structure of the title compound, [Cu(C(10)H(6)NO(2))(C(7)H(5)O(2))(C(10)H(7)NO(2))], contains copper(II) ions five-coordinated in a distorted trigonal-bipyramidal environment. The equatorial plane is occupied by three O atoms, one from the carboxyl-ate group of the benzoate ion considered as occupying a single coordination site, the other two from two carboxyl-ate groups of the quinaldic acid and quinaldate ligands. The axial positions are occupied by the N atoms of the quinoline ring system. The metal ion lies on a twofold axis that bisects the benzoate ion. The quinaldate and quinaldic acid ligands are equivalent by symmetry, and the carboxyl-ate/carboxyl groups are disordered. The disordered H atom is shared between the carboxyl-ate groups of adjacent quinaldic acid mol-ecules. Such hydrogen bonds delineate zigzag chains that run along the c axis. The structure is very similar to that of the Mn(II) analog.

(Benzoato-κO,O')(quinoline-2-carboxyl-ato-κN,O)(quinoline-2-carboxylic acid-κN,O)manganese(II).

The crystal structure of the title compound, [Mn(C(7)H(5)O(2))(C(10)H(6)NO(2))(C(10)H(7)NO(2))], contains manganese(II) ions six-coordinated in a distorted octa-hedral environment. The equatorial plane is occupied by four O atoms, two from the carboxyl-ate group of the benzoate ion, the other two from carboxyl-ate/carboxyl groups of the quinaldate/quinaldic acid mol-ecules. The axial positions are occupied by the N atoms of the quinoline ring systems. The metal ion lies on a twofold rotation axis that bisects the benzoate ligand; the quinaldate and quinaldic acid ligands are therefore equivalent by symmetry, and the carboxylate/carboxyl groups are disordered. The complexes are joined together by hydrogen bonds between the carboxyl-ate/carboxyl groups of adjacent quinaldate/quinaldic acid mol-ecules, forming zigzag chains that run along the c axis.