Synthesis, spectroscopy, X-ray crystallography, DFT calculations, DNA binding and molecular docking of a propargyl arms containing Schiff base.

A propargyl arms containing Schiff base (L) was synthesized by the condensation of 1-[2-hydroxy-4-(prop-2-yn-1-yloxy)phenyl]ethanone with trans-1,2-diaminocyclohexane. The structure of L was characterized by IR, (1)H NMR, (13)C NMR and UV-Vis spectroscopy and by single crystal X-ray diffraction analysis. The UV-Visible spectral behavior of L in different solvents exhibits positive solvatochromism. Density functional calculation of the L in gas phase was performed by using DFT (B3LYP) method with 6-31G basis set. The computed vibrational frequencies and NMR signals of L were compared with the experimental data. Tautomeric stability study inferred that the enolimine is more stable than the ketoamine form. The charge delocalization has been analyzed using natural bond orbital (NBO) analysis. Electronic absorption and emission spectral studies were used to study the binding of L with CT-DNA. The molecular docking was done to identify the interaction of L with A-DNA and B-DNA.

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.