Chiral crystallization of a zinc(II) complex.

The compound, {6,6'-dimeth-oxy-2,2'-[(4-azaheptane-1,7-di-yl)bis-(nitrilo-meth-an-yl-idyne)]diphenolato}zinc(II) methanol monosolvate, [Zn(C22H27N3O4)]·CH3OH, at 298 K crystallizes in the ortho-rhom-bic space group Pna21. The Zn atom is coordinated by a penta-dentate Schiff base ligand in a distorted trigonal-bipyramidal N3O2 geometry. The equatorial plane is formed by the two phenolic O and one amine N atom. The axial positions are occupied by two amine N atoms. The distorted bipyramidal geometry is also supported by the trigonality index (τ), which is found to be 0.85 for the mol-ecule. In the crystal, methanol solvent mol-ecule is connected to the complex mol-ecule by an O-H⋯O hydrogen bond and the complex mol-ecules are connected by weak supra-molecular inter-actions, so achiral mol-ecules generate a chiral crystal. The Hirshfeld surface analysis suggests that H⋯H contacts account for the largest percentage of all inter-actions.

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 mol-ecules in the asymmetric unit. The Cu(II) atoms are each coordinated by the penta-dentate 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 mol-ecules are each connected into a column along the b axis through inter-molecular 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-amino-ethyl)amino]-ethyl}imino)-meth-yl]-6-hy-droxy-phenolato-κ(4) N,N',N'',O (1)}(nitrato-κO)copper(II) ethanol 0.25-solvate.

In the crystal structure of the title mononuclear Cu(II) 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 Cu(2+) 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 Cu(II) atom to move slightly out of the approximate basal plane toward the bound nitrate group. The structure exhibits disorder of the ethanol solvent mol-ecule.

A prospective comparison of chronic primary angle-closure glaucoma versus primary open-angle glaucoma in Singapore.

INTRODUCTION: To describe the optic disc, visual field and ocular characteristics of a consecutive cohort of Asian patients with chronic primary angle-closure glaucoma (CPACG), and compare them with those having primary open-angle glaucoma (POAG). METHODS: In a prospective comparative case series of new patients with POAG or CPACG in Singapore, all patients underwent visual acuity assessment, slit-lamp examination, tonometry, gonioscopy, refraction, Heidelberg Retina Tomograph (HRT) and Humphrey visual field (HVF) assessment. RESULTS: 98 patients were enrolled (POAG n = 48; CPACG n = 50). CPACG patients were significantly older (66.5 ± 9.2 years vs. 64.1 ± 13.5 years; p = 0.027) and mostly female (p = 0.004). CPACG eyes had significantly higher intraocular pressure (26.9 ± 6.9 mmHg vs. 24.5 ± 3.3 mmHg; p = 0.03), shorter axial length (22.89 ± 0.97 mm vs. 24.26 ± 1.79 mm; p < 0.001) and shallower anterior chamber depth (2.60 ± 0.25 mm vs. 3.16 ± 0.48 mm; p < 0.001). HVF mean deviation or pattern standard deviation (PSD) did not differ significantly between POAG and CPACG eyes, but the latter had a lower PSD for a given mean deviation. HRT parameters between the two groups were not significantly different. CONCLUSION: In this study, CPACG eyes had significantly higher presenting intraocular pressure than POAG eyes, but there were no significant differences in optic disc topography. A majority of the patients in both groups had moderate field defects at the time of presentation, followed by severe and then mild defects. The field loss in CPACG eyes was more diffuse than that in POAG eyes.

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.

Spectral and physico-chemical investigations of novel homo-dinuclear di-micro2-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 Kramer's double degeneracy. The neighboring Fe(III) nuclei in the homo-dinuclear species are antiferromagnetically coupled.

Synthesis, physico-chemical and spectral investigations of novel homo-bimetallic mixed-ligand complexes: 57Fe Mössbauer parameters of [Fe2(imda)2(H2O)3Cl].

The newly prepared homo-bimetallic complexes [M(2)(imda)(2)(H(2)O)(4)], [M(2)(imda)(2)(Bipy)(2)] (M=Co, Ni or Cu) and [Fe(2)(imda)(2)(H(2)O)(3)Cl] (H(2)imda=iminodiacetic acid and Bipy=2,2'-bipyridine) have been studied employing IR, FAB-mass, (1)H and (13)C NMR, EPR and ligand field spectra, which indicated a high-spin state of metal ion with hexa-coordinate environment. (57)Fe Mössbauer data of the homo-bimetallic complex [Fe(2)(imda)(2)(H(2)O)(3)Cl] confirm a high-spin configuration with Fe (+/-3/2-->1/2) nuclear transitions and the presence of Kramer's double degeneracy. At RT, the spin-spin interactions of the neighbouring nuclei (Fe(3+)-Fe(3+)=S(5/2)-S(5/2)) are anti-ferromagnetically coupled. However, at LNT, the complex acquires a mixed-valent [Fe(III)-Fe(II)] composition corroborated from the X-band EPR data. CV studies indicated the presence of quasi-reversible redox Cu(II/I), Cu(II/III), Fe(III/II), Fe(III/I) and Fe(II/I) couples.

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.

Spectroscopic and antimicrobial studies of La3+, Pr3+, Nd3+ and Gd3+ complexes of a dipodal [N,N,N] chelating ligand.

The lanthanide complexes of bis(benzimidazole-2'-yl-methyl)amine (BImz) having molecular formula [M(BImz)X(3)H(2)O]*nH(2)O (M = La, Pr, Nd, or Gd; X = Cl or ClO(4) and n = 1, 2 or 3) were prepared and characterized spectroscopically through IR, (1)H and (13)C NMR, FAB-mass, UV-visible and luminescence spectroscopy. TGA data suggested presence of coordinated and the lattice water. The oscillator strengths of the f-f transitions and the covalency parameters (beta, b(1/2) and delta) have been evaluated from the electronic spectral data. The proposed hepta-coordinate geometry for the complexes has been ascertained from the molecular model computations. CV studies indicate formation of a stable quasi-reversible redox couple Gd(III/IV) in the solution. The in vivo antimicrobial activities of the complexes have been evaluated against gram +ve and gram -ve bacteria and fungi.