2,6-Diphenyl-3-(prop-2-en-1-yl)piperidin-4-one.

In the title compound, C20H21NO, the dihedral angle between the phenyl ring is 47.5 (1)° and the piperidine ring adopts a chair conformation. In the crystal, mol-ecules are linked by C-H⋯π inter-actions into dimers with the mol-ecules related by twofold symmetry.

Novel mixed ligand complexes of bioactive Schiff base (E)-4-(phenyl (phenylimino) methyl) benzene-1,3-diol and 2-aminophenol/2-aminobenzoic acid: synthesis, spectral characterization, antimicrobial and nuclease studies.

A novel bidentate Schiff base ligand has been synthesized using 2,4-dihydroxybenzophenone and aniline. Its mixed ligand complexes of MAB type [M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); HA=Schiff base and B=2-aminophenol/2-aminobenzoic acid] have been synthesized and characterized on the basis of spectral data UV-Vis, IR, (1)H NMR, FAB-Mass, EPR, SEM and magnetic studies. All the complexes were soluble in DMF and DMSO. Elemental analysis and molar conductance values indicate that the complexes are non-electrolytes. HA binds with M(II) ions through azomethine and deprotonated phenolic group and B binds through the primary amine group and deprotonated phenolic/carboxylic groups. Using FAB-Mass the cleavage pattern of the ligand (HA) has been established. All the complexes adopt octahedral geometry around the metal ions. It has been confirmed with the help of UV-Vis, IR, (1)H NMR and FAB-Mass spectral data. DNA binding activities of the complexes 1d and 2d are studied by UV-Vis spectroscopy and cleavage studies of Schiff base ligand and its complexes 1d and 2d have been by agarose gel electrophoresis method. In vitro biological activities of the free ligand (HA) and their metal complexes (1a-1e and 2a-2e) were screened against few bacteria, Escherichia coli, Staphylococcus saphyphiticus, Staphylococcus aureus, Pseudomonas aeruginosa and fungi Aspergillus niger, Enterobacter species, Candida albicans by well diffusion technique.

Synthesis, characterization and biocidal activities of some schiff base metal complexes.

Some new mixed ligand complexes (1-5) of type ML'B (M(II)=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); HL'= o-vanillidene-2-aminobenzothiazole; B= 1,10-phenanthroline) and Schiff base metal complexes of types (ML(2)") (6-10) and (M(2)L") (11-15) (HL"= o-vanillidene-2-amino-N-(2-pyridyl)-benzene sulfonamide) were synthesized and characterized by elemental analysis and spectral (IR, (1)H NMR and (13)C NMR) studies. The free ligands and their metal complexes have been screened for their in vitro biological activities against bacteria, fungi and yeast. The metal complexes show more potent activities compared with Schiff base ligands.

pH Metric, Spectroscopic and Thermodynamic Study of Complexation Behavior of 2-aminobenzothiazole with Ni (II) in Presence of Amino Acids.

The complexation of 2-aminobenzothiazole (2abt) [A] with Ni(II) in presence of amino acids viz., glycine (gly), L-alanine (ala), L-valine (val) and L-phenylalanine (pal) [B] in 50% (v/v) water-ethanol mixture containing NaClO4 (0.15 M) has been studied by pH metrically at various temperatures (300, 310, 320 and 330 ± 0.1 K). Mixed ligand complexes of types NiAB and NiAB2 were observed and their stability constants were determined. The stabilization of mixed ligand complexes over binary analogues has been derived from Δ log K, log X' and log X values. The thermodynamic parameters ΔG, ΔH and ΔS were derived from the temperature dependence of the equilibrium constants. The complexation behavior has also been studied by means of electronic spectra. On the basis of stability constants and electronic spectra, it is revealed that the mixed ligand complexes have six-coordinated octahedral structure. The binary and mixed ligand complexes were screened for their microbial activities in vitro on common bacteria, fungi and yeast. The DNA cleaving activities were studied by electrophoresis method.

Spectral characterization, cyclic voltammetry, morphology, biological activities and DNA cleaving studies of amino acid Schiff base metal(II) complexes.

Metal complexes are synthesized with Schiff bases derived from o-phthalaldehyde (opa) and amino acids viz., glycine (gly) l-alanine (ala), l-phenylalanine (pal). Metal ions coordinate in a tetradentate or hexadentate manner with these N(2)O(2) donor ligands, which are characterized by elemental analysis, molar conductance, magnetic moments, IR, electronic, (1)H NMR and EPR spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Based on EPR studies, spin-Hamiltonian and bonding parameters have been calculated. The g-values calculated for copper complexes at 300K and in frozen DMSO (77K) indicate the presence of the unpaired electron in the dx2-y2 orbital. The evaluated metal-ligand bonding parameters showed strong in-plane sigma- and pi-bonding. X-ray diffraction (XRD) and scanning electron micrography (SEM) analysis provide the crystalline nature and the morphology of the metal complexes. The cyclic voltammograms of the Cu(II)/Mn(II)/VO(II) complexes investigated in DMSO solution exhibit metal centered electroactivity in the potential range -1.5 to +1.5V. The electrochemical data obtained for Cu(II) complexes explains the change of structural arrangement of the ligand around Cu(II) ions. The biological activity of the complexes has been tested on eight bacteria and three fungi. Cu(II) and Ni(II) complexes show an increased activity in comparison to the controls. The metal complexes of opapal Schiff base were evaluated for their DNA cleaving activities with calf-thymus DNA (CT DNA) under aerobic conditions. Cu(II) and VO(II) complexes show more pronounced activity in presence of the oxidant.

Spectral, XRD, SEM and biological activities of transition metal complexes of polydentate ligands containing thiazole moiety.

Metal complexes of o-vanillidene-2-aminobenzothiazole have been prepared and characterized by elemental and spectral (vibrational, electronic, 1H NMR and EPR) data as well as magnetic susceptibility measurements and thermo gravimetric analysis (TG/DTA). The low molar conductance values reveal the non-electrolytic nature of these complexes. The elemental analysis suggests that the stoichiometry to be 1:2 (metal:ligand). Magnetic susceptibility data coupled with electronic spectra suggest that two ligands coordinate to each metal atom by phenolic oxygen and imino nitrogen to form high spin octahedral complex with Co(II), Mn(II) and Ni(II). The fifth and sixth position of metal ion is satisfied with water molecules. The thermal behaviour (TG/DTA) of the synthesised complexes shows that the complexes loss water molecules in the first step followed by decomposition of the ligand. Spin Hamiltonian parameters predict a distorted tetrahedral geometry for the copper complex. XRD and SEM analysis provide the crystalline nature and the morphology of the metal complexes. The in vitro biological activity of the metal chelates is tested against the Gram positive bacteria (Bacillus amyloliquifacians) and gram negative bacteria (Pseudomonas species), fungus (Aspergillus niger) and yeast (Sacchromyces cereviaceae). Most of the metal chelates exhibited higher biological activities.