A modified pH 1.0 liquid redox sulfur recovery (LRSR) process, based on reactive absorption of H(2)S((g)) in an acidic (pH 1.0) iron solution ([Fe(III)] = 9-8 g L(-1), [Fe(II)] = 1-2 g L(-1)) and electrochemical regeneration of the Fe(III)/Fe(II) catalyst couple, is introduced. Fe(II) was oxidized in a flow-through electrolytic cell by Cl(2(aq)) formed on a Ti/RuO(2) anode. pH 1.0 was applied t...

A series of bimetallic, trigonal bipyramidal clusters of type {[Co(N-N)(2)](3)[Fe(CN)(6)](2)} are reported. The reaction of {Co(tmphen)(2)}(2+) with [Fe(CN)(6)](3)(-) in MeCN affords {[Co(tmphen)(2)](3)[Fe(CN)(6)](2)} (1). The cluster can exist in three different solid-state phases: a red crystalline phase, a blue solid phase obtained by exposure of the red crystals to moisture, and a red solid...

The Fe(II) of the binuclear Fe(II)Fe(III) active site of pig purple acid phosphatase (uteroferrin) has been replaced in turn by five M(II) ions (Mn(II), Co(II), Ni(II), Cu(II), and Zn(II)). An uptake of 1 equiv of M(II) is observed in all cases except that of Cu(II), when a second more loosely bound Cu(II) is removed by treatment with edta. The products have been characterized by different anal...

A new biomimetic model for the heterodinuclear heme/copper center of respiratory oxidases is described. It is derived from iron(III) protoporphyrin IX by covalent attachment of a Gly-L-His-OMe residue to one propionic acid substituent and an amino-bis(benzimidazole) residue to the other propionic acid substituent of the porphyrin ring, yielding the Fe(III) complex 1, and subsequent addition of ...

Oligocholate macrocycles self-assemble into transmembrane nanopores by the associative interactions of water molecules inside the amphiphilic macrocycles. Macrocycles functionalized with a terephthalic acid "side chain" displayed significantly higher transport activity for glucose across lipid bilayers than the corresponding methyl ester derivative. Changing the 1,4-substitution of the dicarbox...

Three imine macrocycles having rhomboidal shape were synthesized in good yields by [2+2] cyclocondensation reaction between equimolar quantities of (R,R)-1,2-diaminocyclohexane and 4,4'-bisformyl triphenylamine derivatives. The macrocycles structure was assigned by electrospray ionization mass spectrometry (ESI-MS), (1)H-NMR, and elemental analysis. UV, FTIR spectroscopy, and TG measurements we...

Some nitrate- and Fe(III)-reducing microorganisms are capable of oxidizing Fe(II) with nitrate as the electron acceptor. This enzymatic pathway may facilitate the development of anaerobic microbial communities that take advantage of the energy available during Fe-N redox oscillations. We examined this phenomenon in synthetic Fe(III) oxide (nanocrystalline goethite) suspensions inoculated with m...

Histone deacetylase 8 (HDAC8) was originally classified as a Zn(II)-dependent deacetylase on the basis of Zn(II)-dependent HDAC8 activity in vitro and illumination of a Zn(II) bound to the active site. However, in vitro measurements demonstrated that HDAC8 has higher activity with a bound Fe(II) than Zn(II), although Fe(II)-HDAC8 rapidly loses activity under aerobic conditions. These data sugge...

Studies of oxygen equilibrium properties of Mg(II)-Fe(II) and Zn(II)-Fe(II) hybrid hemoglobins (i.e. alpha2(Fe)beta2(M) and alpha2(M)beta2(Fe); M=Mg(II), Zn(II) (neither of these closed-shell metal ions binds oxygen or carbon monoxide)) are reported along with the X-ray crystal structures of alpha2(Fe)beta2(Mg) with and without CO bound. We found that Mg(II)-Fe(II) hybrids resemble Zn(II)-Fe(II...

Rigid rod-type metallo-supramolecular coordination polyelectrolytes with Fe(II) centres (Fe-MEPEs) are produced via the self-assembly of the ditopic ligand 1,4-bis(2,2':6',2''-terpyridine-4'-yl)benzene (tpy-ph-tpy) and Fe(II) acetate. Fe-MEPEs exhibit remarkable electrochromic properties; they change colour from blue to transparent when an electric potential is applied. This electrochemical pro...