In the title compound, [CoBr(C 2 H 8 N 2 ) 2 (C 4 H 11 N)]Br 2 , the cobalt(III) ion has a distorted octahedral coordination environment and is surrounded by four N atoms in the equatorial plane made up of three N atoms from the two ethylenediamine ligands and the remaining N from the n-butyl substituent, with the other N atom from the ethylenediamine ligand and the Br atom occupying the axial positions. In the crystal, the complex cation and the two counter-anions are linked via N-HÁ Á ÁBr and C-HÁ Á ÁBr hydrogen bonds, forming a threedimensional network. The crystal studied was refined as a two-component inversion twin. Structure descriptionMixed-ligand cobalt(III) complexes exhibit antitumor, antibacterial, antimicrobial, radiosenzitation and cytotoxicity activities (Sayed et al., 1992;Teicher et al., 1990;Arslan et al., 2009;Delehanty et al., 2008). Cobalt is an essential and integral component of vitamin B12 and is therefore found physiologically in most tissues. Complexes of cobalt are useful for nutritional supplementation to provide cobalt in a form, which effectively increases its bioavailability, for instance, vitamin B12 by microorganisms present in the gut. In addition, cobalt(III) complexes are known for electron-transfer and ligandsubstitution reactions, which find applications in chemical and biological systems. Our present research concerns the design and synthesis of cobalt(III) complexes with the objective of understanding the structure-reactivity correlation. Substituting a different amino ligand for the MeNH 2 moiety can yield complexes of similar structure, but with

In the title complex, [CoBr(C2H7N)(C2H8N2)2]Br2, the CoIII centre has a distorted octahedral coordination environment, and is surrounded by four N atoms in the equatorial plane, with an additional N atom and the Br atom occupying the axial positions. The complex is isostructural with the Cl compound for which the X-ray structure has also been reported [Anbalagan, Mahalakshmi & Ganeshraja (2011). J. Mol. Struct. 1005, 45–52]. In the crystal, the complex cation and the two counter-anions are linked via N—H...Br hydrogen bonds, forming a three-dimensional network.

In the title compound, [CoBr(CH 5 N)(C 2 H 8 N 2 ) 2 ]Br 2 , the cobalt(III) ion has a distorted octahedral coordination environment and is ligated by four N atoms in the equatorial plane, with an additional N atom and a Br À ion occupying the axial positions. In the crystal, the complex cation and the two counter-anions are linked via N-HÁ Á ÁBr and C-HÁ Á ÁBr hydrogen bonds, forming a supramolecular framework. Structure descriptionMixed-ligand cobalt(III) complexes exhibit antitumor, antibacterial, antimicrobial, radiosenzitation and cytotoxicity activities (Sayed et al., 1992;Teicher et al., 1990;Arslan et al., 2009;Delehanty et al., 2008). Cobalt is an essential and integral component of vitamin B12 and is therefore found physiologically in most tissues. Cobalt(III) complexes are known for their involvement in electron-transfer and ligand-substitution reactions, which find applications in chemical and biological systems. Our present research concerns the design and synthesis of cobalt(III) complexes with the objective of understanding of their structure-reactivity correlations. Substituting an amino ligand for the MeNH 2 moiety can yield complexes of similar structure, but with differing electron-transfer rates (Anbalagan, 2011;Anbalagan et al., 2011).The molecular structure of the title compound is illustrated in Fig. 1. The cobalt(III) ion has a distorted octahedral coordination environment and is ligated by four N atoms (N1, N2, N3 and N5) in the equatorial plane, with N atom (N4) and the Br À ion (Br1) occupying the axial positions. The Co1-N(ethylene-1,2-diamine) bond lengths vary from