Manganese( III) has been stabili zed in weakly acidic med ium by means of pyrophosphate and the nature of the complex elucidated spectrophotometricall y. Stoichiometry of manganese( JJJ) oxidation of aspirin (acetylsalicylic acid) in pyrophosphate has been establi shed in the pH range 2.3-3.5 by iodometric and spectrophotometric methods. The reac ti on foll ows first order kinetics in [Mn(IIl)j...

Bacillus subtilis class Ib ribonucleotide reductase (RNR) catalyzes the conversion of nucleotides to deoxynucleotides, providing the building blocks for DNA replication and repair. It is composed of two proteins: α (NrdE) and β (NrdF). β contains the metallo-cofactor, essential for the initiation of the reduction process. The RNR genes are organized within the nrdI-nrdE-nrdF-ymaB operon. Each p...

In this study, we generated phosphoserine- and phosphothreonine-containing peptide radical cations through low-energy collision-induced dissociation (CID) of the ternary metal-ligand phosphorylated peptide complexes [Cu(II)(terpy)(p)M](·2+) and [Co(III)(salen)(p)M](·+) [(p)M: phosphorylated angiotensin III derivative; terpy: 2,2':6',2''-terpyridine; salen: N,N'-ethylenebis(salicylideneiminato)]...

the reaction of an equivalent of 2- mercaptoethyl ammonium chloride with an equivalent of 2,6-diformyl -4- methyl phenol produced monoamine which was reacted with half equivalent of 1,2-diamine ethane to produce ethylene-bis-6-(2-mercapto-ethyl-imine)-methyl -4- methyl phenol [h4l]. the ligand was reacted with metal ions[cr(iii), mn(ii), fe(ii), co(ii), ni(ii), cu(ii), zn(ii), cd(ii), and hg(ii...

A dinuclear manganese(III) complex (1) of an N-(carboxymethyl)-N-[3,5-bis(α,α-dimethylbenzyl-2-hydroxybenzyl)]glycine (HDA) ligand (L) binds a manganese(II) species through displacement of its solvating ligands by appropriately dispositioned carbonyl groups of a dinuclear complex {[Mn(2)(L)(2)(OH)(OCH(3))][Mn(H(2)O)(3)(CH(3)OH)(3)], 2, triclinic P1, a = 13.172(3) Å, b = 15.897(3) Å, c = 19.059(...

We studied the effect of manganese and various organic chelators on the distribution, depolymerization, and mineralization of synthetic 14C-labeled lignins (DHP) in cultures of Phanerochaete chrysosporium. In the presence of high levels of manganese [Mn(II) or Mn(III)], along with a suitable chelator, lignin peroxidase (LiP) production was repressed and manganese peroxidase (MnP) production was...

we have prepared and characterized a few mn (iii) complexes by using a few bidentate and tridentate ligands. spectra of the manganese (abstract we have prepared and characterized a few mn (iii) complexes by using a few bidentate and tridentate ligands. spectra of the manganese (iii) ion in a variety of molecular environments are reported . on the basis of solution spectra, some of these complex...

The synthesis, structures and magnetic properties of two new mixed-valence heptanuclear manganese clusters are described. Both complexes utilize triethanolamine (teaH(3)) as a bridging ligand, displaying near planar, disc-like metal topologies and are of formulae [Mn(II)(4)Mn(IV)(3)(tea)(teaH(2))(3)(peolH)(4)](BF(4))(2)·solv (1) and [Mn(II)(4)Mn(III)(3)F(3)(tea)(teaH)(teaH(2))(2)(piv)(4)(Hpiv)(...

The capabilities and limitations of the Becke-3-Lee-Yang-Parr (B3LYP) hybrid density functional are investigated as applied to studies of mixed-valent multinuclear oxomanganese complexes. Benchmark calculations involve the analysis of structural, electronic and magnetic properties of di-, tri- and tetra-nuclear Mn complexes, previously characterized both chemically and spectroscopically, includ...

A series of mononuclear Mn(II), Mn(III), and Mn(IV) complexes was prepared using a single tripodal ligand (H(3)L). Addition of a cation (NH(4)(+), K(+), Na(+)) to [Mn(III)L] showed a pronounced effect on the redox potentials. Different variants of Jahn-Teller distortion, axial elongation and compression, were observed in the Mn(III) complexes.