Reaction of the Schiff-base complex [Co(acetylacetonate-ethylenediimine)(NH3)2]+ with metmyoglobin at pH 6.5 yields a partially folded protein containing six Co(III) complexes. Although half of its alpha-helical secondary structure is retained, absorption and CD spectra indicate that the tertiary structure in both B-F and AGH domains is disrupted in the partially folded protein. In analogy to proton-induced unfolding, it is likely that the loss of tertiary structure is triggered by metal-ion binding to histidines. Cobalt(III)-induced unfolding of myoglobin is unique in its selectivity (other proteins are unaffected) and in allowing the isolation of the partially folded macromolecule (the protein does not refold or aggregate upon removal of free denaturant).

Hair chromium concentration (HCC) of normal and diabetic pregnant women was determined by atomic-absorption spectroscopy. For nondiabetic pregnant women the value from 68 hair samples was 472 ± 61 ng/g (x̄ ± 95% CI); for gestational diabetics it was 734 ± 155 ng/g from 42 hair samples. The difference was highly significant (P < 0.005). Intermediate hair chromium concentrations were observed in 20 pregnant women with pregestational, overt diabetes mellitus (x̄: 575 ± 182 ng/g). Fifty-two women had a second hair sample taken later during pregnancy that showed a significant decrease in HCC (P < 0.05). However, this decrease was confirmed only for the diabetic pregnant group. Age and parity did not influence the HCC. The data suggest that impaired utilization of chromium may be a possible etiology for gestational diabetes mellitus.

AbstractAn improved method for the preparation of the monooxotritungsten hexaacetate cluster (IIIa) is described starting with Na tungstate (I) as demonstrated in the scheme.

The reaction of CuO with L-ornithine in basic boiling water solution results in the formation of [bis(1-pyrroline-2-carboxylate)copper(II)]·8H2O. The complex, C10H28CuN2O12, Mx=431.9 crystallizes in the monoclinic space group P21/n with Z=2. Cell dimensions are: a=6.849(4), b=20.552(4), c=7.291(4) Å, β=108.79(5)°, V=971.6 Å3. The structure was refined to R=0.067 and Rw=0.051. The complex is centrosymmetric with the copper atoms at (0,0,0) and (12,12,12) inversion centers. The geometry around the copper atom is essentially (4 + 2)-elongated octahedron. The ligand 1-pyrroline-2-carboxylate which is obtained by oxidation of L-ornithine to the corresponding α-keto acid followed by cyclization has a slight deviation from planarity. The water molecules of hydration form through hydrogen bonding a specially interesting three dimensional network in the crystal.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFurther studies of the monooxo-capped tritungsten carboxylate clustersAvi Bino, F. Albert Cotton, Zvi Dori, Miriam Shaia-Gottlieb, and Moshe KaponCite this: Inorg. Chem. 1988, 27, 20, 3592–3596Publication Date (Print):October 1, 1988Publication History Published online1 May 2002Published inissue 1 October 1988https://pubs.acs.org/doi/10.1021/ic00293a030https://doi.org/10.1021/ic00293a030research-articleACS PublicationsRequest reuse permissionsArticle Views127Altmetric-Citations30LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural characterization of the product of oxidation of a macrocyclic cobalt(II) complex in pyridine solutionEliana Sister, Varda Gottfried, Moshe Kapon, Menahem Kaftory, Zvi Dori, and Harry B. GrayCite this: Inorg. Chem. 1988, 27, 4, 600–604Publication Date (Print):February 1, 1988Publication History Published online1 May 2002Published inissue 1 February 1988https://pubs.acs.org/doi/10.1021/ic00277a007https://doi.org/10.1021/ic00277a007research-articleACS PublicationsRequest reuse permissionsArticle Views145Altmetric-Citations26LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

AbstractThe title reaction gives the Co(III) complexes (II) isolated as their BF4 salts.

AbstractThe title compound (I) is formed by addition of an excess of potassium hydrido‐tris(pyrazolyl)borate to a solution of the cuboidal Mo4S4‐aquo ion.

AbstractThe reaction of (Mo4S4(NCS)12)6‐ in degassed H2O with the cyclic amine 1,4,7‐triazacyclononane initially yields a solution from which, depending on the reaction conditions, two fragmentation products are isolated.

The paramagnetic Co(II) complex (I) binds dioxygen in solutions containing equimolar concentra‐ tions of N‐bases.

The paramagnetic Co(II) complex of 5,14-dihydro-dibenzo[b,i] [5,9,14,18]tetraaza[14]annulen-(L) binds dioxygen in solutions containing equimolar concentrations of imidazole and other nitrogen bases. In excess base the paramagnetic Co(II)-dioxygen complex is converted to a diamagnetic Co(III) complex as shown by ESR, NMR, visible spectroscopy and X-ray crystallography.

AbstractThe title reaction results in the formation of the unusual product (II), which crystallizes in the space group PT with Z=1.

AbstractAconvenient method for preparing a solution of Mo3S2+ employs the reaction of Mo(CO)6 with Na2S in acetic anhydride (lOh reflux under N2) and hydrolysis of the solution.

AbstractFirst Alkylidyne‐Capped Tritungsten(IV) Cluster Compounds: Preparation, Structure, and Properties of [W3O(CCH3)(O2CCH3)"(H2O)3lB ‐, ‐ 2 H2O. ‐ The equilateral trinuclear Cluster cation of (I) is obtained from the reaction of W(CO)4(piperidine)2 and a mixture of acetic acid and acetic anhydride.

This chapter contains sections titled: Molybdenum(II)Aqua Dimer Hexaaqyamolybdenum(III) Molybdenum(III)Aqua Dimer Molybdenum(IV) Aqua Trimer Molybdenum(V) Aqua Dimer Molybdenum(VI) Aqua Ions