On weighted lowdin orthogonalization

Let f1 , fn be a basis of unit vectors and g1 , gn an orthonormal basis in a Hilbert space. We consider and solve the problem of finding an orthonormal basis e1, , en such that a weighted average of the distance of ej from fj and gj is minimized in the sense of least squares

Mononuclear oxidodiperoxido vanadium(V) complex: synthesis, structure, VHPO mimicking oxidative bromination, and potential detection of hydrogen peroxide

<p>An oxidodiperoxidovanadium(V) complex, (NH₄)[VO(O₂)₂(phen)](H₂O)₂, has been synthesized and structurally characterized. The complex crystallizes in the <i>P2</i>_<i>1</i>/<i>c</i> space group. The vanadium center is seven-coordinate with pentagonal bipyramidal geometry. The compound was designed in order to develop a VHPO mimic, so it was tested for VHPO activity through the single pot bromination of phenol red to bromophenol blue whereby, it afforded positive response to establish that the complex is indeed a VHPO mimic. In addition, the compound is capable of detection of H₂O₂.</p

Synthesis, structure, DNA binding studies and nuclease activities of two luminescent neodymium complexes

<p>Two neodymium(III) complexes, [Nd(Phen)(NO₃)₃(DMF)₂] (<b>1</b>) and [Nd(Phen)₂(NO₃)₃] (<b>2</b>) (phen = 1,10-phenanthroline; DMF = dimethylformamide), have been synthesized with a view to design artificial luminescent nucleases and nuclease mimics. The complexes were characterized by spectroscopic, powder, and single crystal XRD studies. The complexes, as expected, have luminescent properties. The DNA binding studies of both complexes have been carried out by spectroscopic studies e.g. electronic absorption (UV–Vis), fluorescence emission as well as viscosity measurements. The nuclease activity of the complexes has been established by gel electrophoresis using pUC19 circular plasmid DNA. The results of DNA binding as well as DNA cleavage activity and the model studies of interaction with <i>p</i>NPP indicate that both neodymium complexes demonstrate nuclease activity through phosphoester bond cleavage.</p

Synthesis, structural characterization and catalytic activity of a multifunctional enzyme mimetic oxoperoxovanadium(v) complex

The synthesis and structural characterization of a novel oxoperoxovanadium(v) complex [VO(O-2)(PAH)-(phen)] containing the ligands 2-phenylacetohydroxamic acid (PAHH) and 1,10-phenanthroline (phen) has been accomplished. The oxoperoxovanadium(v) complex was found to mimic both vanadate-dependent haloperoxidase (VHPO) activity as well as nuclease activity through effective interaction with DNA. The complex is the first example of a structurally characterized stable oxoperoxovanadium(v) complex with a coordinated bi-dentate hydroximate moiety (-CONHO-) from 2-phenylacetohydroximate (PAH). The oxoperoxovanadium(v) complex has been used as catalyst for the peroxidative bromination reaction of some unsaturated alcohols (e.g. 4-pentene-1-ol, 1-octene-3-ol and 9-decene-1-ol) in the presence of H2O2 and KBr. The catalytic products have been characterized by GC-MS analysis and spectrophotometric methods. The DNA binding of this complex has been established with CT DNA whereas the DNA cleavage was demonstrated with plasmid DNA. The interactions of the complex with DNA have been monitored by electronic absorption and fluorescence emission spectroscopy. Viscometric measurements suggest that the compound is a DNA intercalator. The nuclease activity of this complex was confirmed by gel electrophoresis studies

A gadolinium(III) complex: synthesis, structure, photophysical profile and its role in the degradation of nitroaromatics

<p>The synthesis and structural characterization of a gadolinium(III) complex with phenanthroline and thiocyanate ligands have been accomplished. The X-ray crystal structure reveals that Gd(III) in a slightly distorted square anti-prism coordinated with four thiocyanate ions and two phenanthroline molecules; one phenanthroline is protonated which compensates the charge of Gd(III) center. The crystal structure shows chemically significant non-covalent interactions like hydrogen bonding involving the thiocyanate ligand and <i>π</i>–<i>π</i> interactions between uncoordinated phenanthrolinium and coordinated phen. Investigation on the intermolecular interactions and crystal packing via Hirshfeld surface analysis reveals that close contacts are mainly associated with weak interactions. The fingerprint plots demonstrate that these weak interactions are important for crystal packing. The Gd(III) complex shows photophysical activity. The compound is capable of degrading toxic pollutants like nitroaromatics and may have far reaching consequences for cleaning these toxic pollutants from industrial effluents.</p