Shabana Noor

Antimicrobial and SOD activities of novel transition metal complexes of pyridine-2,6-dicarboxylic acid containing 4-picoline as auxiliary ligand.

Ternary complexes are potential models for several mono and polynuclear metal enzymes. The present ternary complexes [Fe(dipic)(4-picoline)]Cl, [M(dipic)(4-picoline)] [M = Co or Ni] and [Cu(dipic)(4-picoline)]n were prepared to exploit as novel antimicrobial agents. The chemical structure and bonding etc. were elucidated by spectral studies. Single crystal X-ray data of the Cu(II) complex indicated formation of 1D coordination polymeric structure. The antimicrobial activities investigated against Escherichia coli (K-12), Bacillus subtilis (MTCC-121), Staphylococcus aureus (IOA-SA-22), Salmonella typhymurium (MTCC-98), Candida albicans, Aspergillus fumigatus and Penicillium marneffei (isolates from Department of Microbiology, Faculty of Agricultural Science, AMU) showed significant activities. The superoxide dismutase (SOD) activity of the Cu(II) complex was also assessed by NBT assay.

Spectral, thermal and electrochemical characterization of novel homo-dinuclear complexes [M2(H3DTPA)(H2O)6]Cl2·xH2O (M=Cr2+, Mn2+, Co2+, Ni2+ or Cu2+).

The title complexes were prepared and characterized employing spectral (FAB-Mass, IR, electronic, (1)H and (13)C NMR), thermal and electrochemical techniques. Analytical and FAB-Mass data suggested a homo-dinuclear stoichiometry. IR and electronic ligand field spectral studies coupled with molecular model computations have indicated a distorted octahedral geometry where the ligand coordinates as a hexadentate dianionic [H(3)DTPA](2-)(H(5)DTPA=diethylenetriaminepentaacetic acid) moiety. The electrochemical redox properties and the antibacterial activities of the compounds were also investigated.

On the Chiral Z′ = 2 Crystal Structure of [Cu2(H2valdien)2](NO3)2 [H2valdien = N1,N3-bis(3-methoxysalicylidene)diethylenetriamine]

AbstractThe crystal and molecular structure of [Cu2(H2valdien)2](NO3)2 (1), whereby H2valdien is the known Schiff base ligand N1,N3-bis(3-methoxysalicylidene)diethylenetriamine, is reported. In 1, two H2valdien ligands join two CuII ions in a chelate–spacer–chelate mode, in which the protonated aliphatic secondary amine moieties represent the spacers, to form a double helix. Both CuII ions in the homodinuclear cationic complex exhibit similar distorted square-planar N2O2 coordination spheres. The axially chiral molecular structure of the [Cu2(H2valdien)2]2+ complex features intramolecular π···π stacking and N–H⋯O hydrogen bonds in the crystal. Compound 1 crystallizes in the Sohncke space group P21, with a = 14.165(3), b = 13.7755(13), c = 21.1185(4) Å, β = 102.199(4)°, and with two enantiomeric molecules in the asymmetric unit (Z′ = 2). The two crystallographically unique [Cu2(H2valdien)2]2+ enantiomers are related by pseudo inversion symmetry.Graphical AbstractThe pseudo centrosymmetric chiral Z′ = 2 crystal structure (space group P21) of [Cu2(H2valdien)2](NO3)2, whereby H2valdien is the known Schiff base ligand N1,N3-bis(3-methoxysalicylidene)diethylenetriamine, is reported.

Crystal structure of {6,6'-dihy-droxy-2,2'-[imino-bis-(propane-1,3-diyl-nitrilo-methanylyl-idene)]diphenolato-κ(5) O (1),N,N',N'',O (1')}copper(II).

The title compound, [Cu(C20H23N3O4)], crystallizes in the space group Cc with two independent molecules in the asymmetric unit. The CuII atoms are each coordinated by the pentadentate Schiff base ligand in a distorted trigonal bipyramidal N3O2 geometry. The equatorial plane is formed by the two phenolic O atoms and the amine N atom, while the axial positions are occupied by the two imine N atoms. In the crystal, the two independent molecules are each connected into a column along the b axis through intermolecular O—H⋯O hydrogen bonds. The two independent columns are further linked through an N—H⋯O hydrogen bond, forming a double-column structure.

Crystal structure of {2-[({2-[(2-amino­ethyl)amino]­ethyl}imino)­meth­yl]-6-hy­droxy­phenolato-κ4N,N′,N′′,O1}(nitrato-κO)copper(II) ethanol 0.25-solvate

In the crystal structure of the title mononuclear CuII complex, [Cu(C11H16N3O2)(NO3)]·0.25C2H5OH, the complex molecules are linked by N—H⋯O and O—H⋯O hydrogen bonds, forming a dimer with an approximate non-crystallographic twofold rotation axis of symmetry. In the monomeric unit, the Cu2+ ion exhibits a distorted square-pyramidal configuration, whereby the anionic [HL]− Schiff base ligand binds in a tetradentate fashion via the O and the three N atoms which all are approximately coplanar. The O atom of a nitrate anion occupies the fifth coordination site, causing the CuII atom to move slightly out of the approximate basal plane toward the bound nitrate group. The structure exhibits disorder of the ethanol solvent molecule.

Spectral and physico-chemical investigations of novel homo-dinuclear di-μ2-alkoxo bridged Schiff base complexes: 57Fe Mössbauer parameters of the Fe(III) complex

Spectral and molecular model computations on homo-dinuclear complexes [M(2)L(2)(H(2)O)(2)Cl(2)] [L=1-(salicylaldeneamino)-3-hydroxypropane, M=Cr(3+), Mn(3+), Fe(3+), Co(3+), Ni(3+) or Cu(3+)] are consistent with a distorted hexa-coordinate geometry. X-band EPR spectral data indicated a rhombic distortion around Cu(II) ion. Magnetic moment and (57)Fe Mössbauer data confirmed a high-spin state electronic configuration (t(2g)(3)e(g)(2), S=5/2) and asymmetric ligand environment around Fe(III) with nuclear transitions Fe(+/-3/2-->1/2) exhibiting Kramers double degeneracy. The neighboring Fe(III) nuclei in the homo-dinuclear species are antiferromagnetically coupled.