Isatin 3-semicarbazone and 1-methyl-isatin 3-semicarbazone

The two title semicarbazones, namely 2,3-dihydro-1H-indole- 2,3-dione 3-semicarbazone, C9H8N4O2, (I), and 1-methyl-2,3- dihydro-1H-indole-2,3-dione 3-semicarbazone, C10H10N4O2, (II), show the same con®guration, viz. Z around the imine C N bond and E around the C(O)ÐNH2 bond, stabilized by two intramolecular hydrogen bonds. The presence of a methyl group on the isatin N atom determines the difference in the packing; in (I), the molecules are linked into chains which lie in the crystallographic (102) plane and run perpendicular to the b axis, while in (II), the molecules are arranged to form helices running parallel to a crystallographic screw axis in the a direction

Cobalt and nickel complexes of versatile imidazole- and pyrrole-2-carbaldehyde thiosemicarbazones. Synthesis, characterisation and antimicrobial activity

Ni(II), Co(II) and Co(III) complexes of imidazole- and pyrrole-2-carbaldehyde thiosemicarbazone ligands (H2L1 and H2L2, respectively) have been prepared. The X-ray crystal structures of [Co(L1)(HL1)], [Ni(H2L1)2]Cl2 _ 3.5H2O and [Ni(HL2)2] have been solved. The Co(III) ion assumes a slightly distorted octahedral coordination geometry, involving both N2S binding domain of diand monoanionic ligand molecules. Whereas in [Ni(HL2)2] the metal ion is tetracoordinated in a square planar geometry by two pyrrole-2-carbaldehyde thiosemicarbazone molecules acting as NS-donor, the spatial array of non deprotonated H2L1 ligand molecules in [Ni(H2L1)2]Cl2 _ 3.5H2O is equivalent to that found for [Co(L1)(HL1)]. The in vitro antimicrobial properties of the ligands and their complexes were tested against representative bacterial and fungal strains in broth culture. The compounds H2L2 and [Co(L2)(HL2)(H2L2)] _ 1.5H2O exhibit a moderate inhibitory effect on the microbial proliferation and only against some Gram positive bacteria