Search results for "ZINC"

A Click‐Functionalized Single‐Molecule Magnet Based on Cobalt(II) and Its Analogous Manganese(II) and Zinc(II) Compounds

2014

A mononuclear CoII single-molecule magnet suitable for click chemistry was investigated. [M(oda)(aterpy)] complexes (oda2– = oxodiacetate, aterpy = 4′-azido-2,2′:6′,2″-terpyridine) with M = MnII, ZnII, and CoII were synthesized as azide-functionalized building blocks for the copper-catalyzed azide–alkyne cycloaddition reaction. The required structural integrity of the complexes in solution was proven in great detail by using ESI-MS and NMR spectroscopy. For the six-coordinate [Co(oda)(aterpy)] complex, single-molecule magnet behavior was confirmed with an effective energy barrier of 4.2 cm–1.

Facile Synthesis and Self‐Assembly of Zinc (2‐Diethoxyphosphorylethynyl)porphyrins

2019

Antenna effects in truxene-bridged BODIPY triarylzinc(ii)porphyrin dyads: evidence for a dual Dexter–Förster mechanism

2014

The antenna process from an energy donor (BODIPY; 4′,4′-difluoro-1′,3′,5′,7′-tetramethyl-4′-bora-3a′,4a′-diaza-s-indacene) in its singlet state to two acceptors (two zinc(II) 5,15-p-tolyl-10-phenylporphyrin) bridged by a central truxene residue (5′,5′′,10′,10′′,15′,15′′-hexabutyltruxene), 5, has been analysed by means of comparison of the energy transfer rates with those of a structurally similar β-substituted BODIPY-(zinc(II) 5,10,15-p-tolyl-porphyrin), 6, where no conjugation is present between the donor and the two acceptors using the Forster resonance energy transfer (FRET) approximation. It is estimated that the energy transfer in 5 operates mostly via a Dexter mechanism (>99%), and th…

Synthesis and characterization of novel quinolyl porphyrins as receptors. Study of their association with halophenols and 4nitrophenol as a reference

2020

International audience; In this work, new receptors built on the porphyrin scaffold were synthesized for halophenols recognition. A quinolyl group was introduced on the porphyrin's periphery as binding site, to form two series of molecules based on two distinct porphyrin frames and which were obtained in free base and zinc forms. The binding between these porphyrin based receptors and halophenols (2,3,4,6tetrachlorophenol, 2,4,6-trichlorophenol or 2,4,6-tribromophenol) was studied. As established by 1 H NMR spectroscopy, the binding constants are in the range of two-digit numbers, which value is correlated with the porphyrin structure (substitutive pattern, form of the free base or Zn II co…

Density functional theory based screening of ternary alkali-transition metal borohydrides: a computational material design project.

2009

We present a computational screening study of ternary metal borohydrides for reversible hydrogen storage based on density functional theory. We investigate the stability and decomposition of alloys containing 1 alkali metal atom, Li, Na, or K M1; and 1 alkali, alkaline earth or 3d / 4d transition metal atom M2 plus two to five BH4  groups, i.e., M1M2BH42‐5, using a number of model structures with trigonal, tetrahedral, octahedral, and free coordination of the metal borohydride complexes. Of the over 700 investigated structures, about 20 were predicted to form potentially stable alloys with promising decomposition energies. The M1Al/ Mn/ FeBH44, Li/ NaZnBH43, and Na/ KNi/ CoBH43 alloys are …

Coordinating behaviour of a new pyridylhydrazone; tris-complexes of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) with 2-pyridylcarb…

1991

The preparation and characterization oftris-complexes of MnII, CoII, NiII, CuII and ZnII with a new pyridylhydrazone, 2-pyridylcarbaldehyde-N,N-dimethylhydrazone (pch), are described. In all the complexes pch behaves as a bidentate ligand binding through the pyridine and azomethyne nitrogen atoms. The complexes appear to be monomeric, high spin six-coordinate, and a distorted octahedral stereochemistry around the metal is suggested. The e.p.r. results for both CuII compounds indicate a mainly dx2−y2 ground state with a static Jahn-Teller distortion, whilst for the MnII complex the e.p.r. data indicates a very low symmetry for the MnN6 polyhedron.

Thermally highly stable amorphous zinc phosphate intermediates during the formation of zinc phosphate hydrate.

2015

The mechanisms by which amorphous intermediates transform into crystalline materials are still poorly understood. Here we attempt to illuminate the formation of an amorphous precursor by investigating the crystallization process of zinc phosphate hydrate. This work shows that amorphous zinc phosphate (AZP) nanoparticles precipitate from aqueous solutions prior to the crystalline hopeite phase at low concentrations and in the absence of additives at room temperature. AZP nanoparticles are thermally stable against crystallization even at 400 °C (resulting in a high temperature AZP), but they crystallize rapidly in the presence of water if the reaction is not interrupted. X-ray powder diffract…

High oxidation state aqueous organometallics: synthesis and structure of a dinuclear oxo(pentamethylcyclopentadienyl)acetato complex of molybdenum(IV…

2003

International audience; The zinc reduction of Cp*2Mo2O5 in a MeOH–H2O mixture in the presence of acetic acid affords the diamagnetic dinuclear compound [Cp*MoO(O2CCH3)]2. An X-ray structural investigation reveals a novel dioxo- and diacetato-bridged structure, with a relatively strong metal–metal bond [2.5524(3) Å]. The compound exhibits a reversible one-electron oxidation process in the cyclic voltammogram. A comparison with other related structures reveals the effect of the electric charge on the mononuclear or dinuclear structural choice.Zinc reduction of Cp*2Mo2O5 in water–methanol in the presence of acetic acid affords compound Cp*2Mo2O2(O2CCH3)2, whose dinuclar tetrabridged structure …

Fluorescence emission and enhanced photochemical stability of Zn(II)-5-triethyl ammonium methyl salicylidene ortho-phenylendiiminate interacting with…

2010

Abstract The photophysical and photochemical properties of the cationic Zn II complex of 5-triethyl ammonium methyl salicylidene ortho-phenylendiimine (ZnL 2+ ) interacting with native DNA were investigated by steady state and time-resolved fluorescence spectroscopies. Experimental results indicate that, in the presence of DNA, ZnL 2+ is efficiently protected from a photochemical process, which occurs when it is in the free state dispersed in aqueous solution. The analysis of the absorption and emission spectra of ZnL 2+ , both stored in the dark and after exposure to tungsten lamp light for 24 h, corroborated by quantum chemical calculations, allowed us to point out that ZnL 2+ undergoes a…

Dynamics of closure of zinc bis-porphyrin molecular tweezers with copper(II) ions and electron transfer.

2011

Zinc bis-porphyrin molecular tweezers composed of a N(4) spacer bound through pyridyl units to the meso position of porphyrins were synthesized, and the tweezers are closed by the coordination of a copper(II) ion inside the spacer ligand. The effect of the π-π interaction between the porphyrin rings in the closed conformation on the absorption spectra of multi-electron oxidized species and the reduction potentials were clarified by chemical and electrochemical oxidation of the closed form of the zinc bis-porphyrin molecular tweezers in comparison with the open form without copper(II) ion and the corresponding porphyrin monomer. The shifts in redox potentials and absorption spectrum of the p…