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{Bis[(heterocycle)ethyl]amine}copper(I) complexes with a least one imidazole ligand react with 0.5 equiv. of dioxygen at −78 °C to give purple peroxo species. The dioxygen adduct of { N -2-[(2-pyridyl)ethyl]- N -2-[1-butyl- 2-imidazolyl)ethyl]amine}copper(I) tetrafluoroborate having one imidazole and one pyridine donor has absorption maxima at 332, 435 and 538 nm and is unreactive toward acid and triphenylphosphine at low temperature, characteristics that have been ascribed to μ-η 2 ,η 2 coordination. {Bis[2-(1-methyl-2-imidazolyl)ethyl]amine}copper(I) tetrafluoroborate ( 11 ) has been structurally characterized by X-ray crystallography and has the expected T-shape. Crystal data for 11 : monoclinic, a =9.2181(21), b =11.638(3), c =14.914(4) A; β=92.059(19)°; Z =4; space group= P 2 1 / c ; 1748 independent non-zero ( I >2.5σ( I ) reflections with 2θ between 2 and 50°; R =6.5%; R w =8.5%.

New hybrid ligands containing combinations of pyrazole, pyridine, and imidazole have been prepared, and the reaction chemistry of their copper(I) derivatives has been studied. The dinucleating ligands provide three nitrogen donors to each metal ion, and each coordination unit is separated by a m-xylyl group. Except for the case where four of the donor groups are pyridyl, in which the xylyl spacer is hydroxylated, all of the complexes react via four-electron reduction of the dioxygen molecule to give bis(μ-hydroxy)copper(II) dimers

New polydentate ligands having (2-imidazolylethyl)amino and (2-benzimidazolylethyl)amino groups have been prepared via the imidate esters derived from N-(2-cyanoethyl)benzamides. These chelating ligands form stable copper(I) complexes that react with dioxygen at low temperature to give adducts presumed to be dinuclear peroxo complexes on the basis of the similarity of their electronic spectra with those for analogous pyridine-ligated species. A Schiff-base ligand derived from isophthalaldehyde and (aminoethyl)imidazole is hydroxylated when its copper(I) derivative is treated with dioxygen

A diverse group of copper-containing proteins carries out the transport and activation of the O2 molecule in biological systems.1–5 Extensive characterization of biomimetic analogs of two of those, namely hemocyanin and tyrosinase, has afforded a better understanding of the inorganic chemistry of peroxocopper complexes at the molecular level.6–12

New polydentate ligands having (2-imidazolylethyl)amino and (2-benzimidazolylethyl)amino groups have been prepared via the imidate esters derived from N-(2-cyanoethyl)benzamides. These chelating ligands form stable copper(I) complexes that react with dioxygen at low temperature to give adducts presumed to be dinuclear peroxo complexes on the basis of the similarity of their electronic spectra with those for analogous pyridine-ligated species. A Schiff-base ligand derived from isophthalaldehyde and (aminoethyl)imidazole is hydroxylated when its copper(I) derivative is treated with dioxygen

New hybrid ligands containing combinations of pyrazole, pyridine, and imidazole have been prepared, and the reaction chemistry of their copper(I) derivatives has been studied. The dinucleating ligands provide three nitrogen donors to each metal ion, and each coordination unit is separated by a m-xylyl group. Except for the case where four of the donor groups are pyridyl, in which the xylyl spacer is hydroxylated, all of the complexes react via four-electron reduction of the dioxygen molecule to give bis(μ-hydroxy)copper(II) dimers

New hybrid ligands containing pyrazole and pyridine have been prepared; and the reaction chemistry of their copper(I) derivatives has been studied. These dinucleating ligands provide three nitrogen donors to each metal ion, and a phenol or phenolate group to bridge between the metals. The reaction of the different dicopper(I) species with dioxygen follows patterns established previously for analogous pyridyl ligands; and peroxo and hydroperoxo adducts can be generated at low temperature

New hybrid ligands containing pyrazole and pyridine have been prepared; and the reaction chemistry of their copper(I) derivatives has been studied. These dinucleating ligands provide three nitrogen donors to each metal ion, and a phenol or phenolate group to bridge between the metals. The reaction of the different dicopper(I) species with dioxygen follows patterns established previously for analogous pyridyl ligands; and peroxo and hydroperoxo adducts can be generated at low temperature

Binucleating ligands that provide three nitrogen donors, and in some cases a phenolate group, to each copper ion have been synthesized. Introduction of substituents to provide steric shielding of the presumed dioxygen-binding site in a previously-described complex prevents reaction of these new species with dioxygen. That these changes are not a direct consequence of steric effects is demonstrated by the synthesis of a Cu(II) derivative having a bridging acetate group. Thus, seemingly simple structural modifications of model systems for the hemocyanin active site may cause substantial changes in reactivity.

Les complexes binucleaires de phenolate pontes servent de modele pour des structures de site actif dans certaines formes des hemocyanine et tyrosinase; les spectres de resonance Raman de ces complexes sont etudies et compares a leurs analogues correspondants mononucleaires

The preparation of transition-metal thiolato complexes as synthetic biomimics1 has led to a resurgent interest in the synthesis of organic thiols and their derivatives. The compound 2,2′-dimercaptobiphenyl, 1, offers interesting possibilities as a ligand, and it has been used recently to displace iron-sulfur clusters from low molecular-weight Fe-S proteins.2 The two previous preparations for 1 require a coupling reaction of diazonium salts.3,4 Overall yields of 10%3 and 30%4 are made even less attractive by the need to precipitate copper by-products with H2S after the coupling step.

Synthese de bis{[(pyrazolyl-1)-2 ethyl] methylamino}-2,6 p-cresol et de son derive t-butyl-3 pyrazole. Preparation de complexes Cu(II)-azoture et Cu(I)-carbonyle. Proprietes magnetiques

Preparation et reactions de CuL 2 BF 4 avec L=emidazoles, pyrazoles et pyridines. Etude RX de Cu(MePz) 2 BF 4 et Cu(Me 3 Py) 2 BF 4

Synthese et caracterisation du coordinat L=bis-[bis-[(pyrazolyl-1)-2 ethyl] aminomethyl]-2,6 p-cresol et etude de son derive complexe dinucleaire Cu(II) μ-hydroxo: C 29 H 38 B 2 Cu 2 F 8 N 10 O 2 cristallise dans P2 1 /c avec Z=4; affinement jusqu'a R=0,073. Mesures de susceptibilite magnetique de 6 a 300 K: fort couplage antiferromagnetique entre les ions cuivre

Several copper(II) complexes have been prepared that use binucleating ligands to yield a coordinatively unsaturated product complex. These complexes will accept an exogenous ligand that binds to a bridging position. We have prepared two families of complexes from 5- or 7-coordinate binucleating ligands that exhibit similar magnetic effects as the exogenous bridging ligands are changed. Complexes of the 7-coordinate binucleating ligand are also especially useful as models of the active site of some binuclear copper proteins (e.g. hemocyanin). We report on our results covering a large series of complexes with exogenous bridging ligands B = Cl - , Br - , OH - , CH 3 CO - 2 , 1,1-N - 3 , 1,3-N - 3 , ClO - 4 , etc. The magnetic exchange interaction for these complexes has not yet been observed to be ferromagnetic, but the magnitude of antiferromagnetic interactions range from Curie-Weiss paramagnetism (B = CH 3 COO - ) to diamagnetism (B = 1,3-N - 3 ).

Synthese de bis{[(pyrazolyl-1)-2 ethyl] methylamino}-2,6 p-cresol et de son derive t-butyl-3 pyrazole. Preparation de complexes Cu(II)-azoture et Cu(I)-carbonyle. Proprietes magnetiques

Preparation et reactions de CuL 2 BF 4 avec L=emidazoles, pyrazoles et pyridines. Etude RX de Cu(MePz) 2 BF 4 et Cu(Me 3 Py) 2 BF 4

The first copper(I) dimer having only a single phenolate bridge has been prepared and structurally characterized; its irreversible oxidation suggests the importance of site isolation in type III copper proteins.