Biomedical subjects

Zeev Gross

Publications and source records attributed to Zeev Gross.

21 records · Page 2Linked to original sources

PubMed1997

Spin Transition in a Manganese(III) Porphyrin Cation Radical, Its Transformation to a Dichloromanganese(IV) Porphyrin, and Chlorination of Hydrocarbons by the Latter.

Chemical oxidation of (TMP)Mn(III)(Cl) (TMP = the tetramesitylporphyrinato dianion) by Fe(ClO(4))(3) leads to the porphyrin-oxidized product (TMP(*)(+))Mn(III)(ClO(4))(2). Magnetic measurements and EPR spectroscopy show that the total spin of the complex changes from S = (5)/(2) at high temperature to S = (3)/(2) at low temperature. Ligand exchange of the perchlorato ligands in (TMP(*)(+))Mn(III)(ClO(4))(2) by chloride anions is accompanied by a change of the oxidation site from porphyrin to metal, resulting in (TMP)Mn(IV)(Cl)(2). This high-valent-metal complex can effect chlorine atom transfer to olefins, as well as to dimedone and chlorodimedone, natural substrates of chloroperoxidases.

Journal Article↗

PubMed1996

One-Pot Synthesis of Dihalo(porphyrinato)osmium(IV) Complexes. Evidence for Monohalo(carbonyl)osmium(III) Intermediates.

trans-Dichloro-, trans-dibromo-, and trans-diiodoosmium(IV) tetraarylporphyrins were obtained by extremely facile synthetic routes directly from the reactions of the corresponding (carbonyl)osmium(II) complexes with CCl(4), CBr(4), and CI(4), respectively. At short reaction times, appreciable amounts of intermediates-one for each reaction-were observed by spectroscopic investigations. These intermediates were shown to be (carbonyl)(halo)(porphyrinato)osmium(III) complexes by independent preparation of an authentic (carbonyl)(bromo)(porphyrinato)osmium(III) complex, which was identical to the reaction intermediate in the reaction of CBr(4) and very similar to those of the other reactions. This provided strong evidence for the reaction mechanism, two stepwise one-electron oxidations of the metal ion. The relatively strong binding of carbon monoxide to osmium(III) is proposed to be an important factor in avoiding dimerization of the reaction intermediates.

Journal Article↗

PubMedDate not supplied

Amphiphilic corroles bind tightly to human serum albumin.

Amphiphilic 2,17-bis-sulfonato-5,10,15(trispentafluorophenyl)corrole (2) and its Ga and Mn complexes (2-Ga and 2-Mn) form tightly bound noncovalent conjugates with human serum albumin (HSA). Protein-induced changes in the electronic absorption, emission, and circular dichroism spectra of these corroles, as well as results obtained from HPLC profiles of the conjugates and selective fluorescence quenching of the single HSA tryptophan, are interpreted in terms of multiple corrole:HSA binding sites. High-affinity binding sites, close to the unique tryptophan, are fully occupied at very low concentrations. At biologically relevant HSA concentrations (2-3 orders of magnitude larger than those employed in our studies), all corroles (2, 2-Ga, and 2-Mn) may be considered as fully conjugated.

Binding Sites↗