2,3-Bis(4-bromo-phen-yl)quinoxaline.

The title compound, C(20)H(12)Br(2)N(2), was prepared by the reaction of 1-(3-bromo-phen-yl)-2-(4-bromo-phen-yl)ethane-1,2-dione with o-phenyl-enediamine in refluxing ethanol. In the mol-ecule, all bond lengths and angles are within normal ranges. The dihedral angle between the two benzene rings is 34.89 (1)°. The dihedral angles between the benzene rings and the quinoxaline system are 57.23 (1) and 36.75 (1)°. The crystal packing is stabilized by van der Waals forces.

A dinuclear CoII complex: bis(mu-dihydrogen phosphato-kappa2O:O')bis[(bipyridine-kappa2N,N')(dihydrogen phosphato-kappaO)cobalt(II)].

The title compound, [Co2(H2PO4)4(C10H8N2)2], is dinuclear, centred on a symmetry centre of the P1 space group. Each Co atom has a distorted square-pyramidal coordination involving two N atoms from a bipyridine molecule and three O atoms from two bridging and one terminal dihydrogen orthophosphate anion. The molecular structure and packing are stabilized by intermolecular hydrogen-bond interactions.

2-Benzoyl-N-phenyl-2-(1,2,4-triazol-1-yl)thioacetamide and 2-(4-methoxybenzoyl)-N-phenyl-2-(1,2,4-triazol-1-yl)thioacetamide.

In the two title compounds, C17H14N4OS, (I), and C18H16N4O2S, (II), the dihedral angles between the planes of the triazole and N-phenyl rings and the plane of five of the atoms that link these two rings are 63.5 (8) and 73.2 (6) degrees for (I), and 65.1 (1) and 72.1 (3) degrees for (II), respectively. There are some inter- and intramolecular interactions in the crystal structure.