Unusual Electronic Structure of First Row Transition Metal Complexes Featuring Redox-Active Dipyrromethane Ligands.
Transition metal complexes (Mn → Zn) of the dipyrromethane ligand, 1,9-dimesityl-5,5-dimethyldipyrromethane (dpm), have been prepared. Arylation of the dpm ligand a to the pyrrolic nitrogen donors limits the accessibility of the pyrrole π-electrons for transition metal coordination, instead forcing...
| Publicado en: | Journal of the American Chemical Society Vol. 131; no. 40; pp. 14374 - 14381 |
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| Autores principales: | , |
| Formato: | Artículo |
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American Chemical Society
10/14/2009
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=44750077&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 44750077 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 10/14/2009 vid: 131 iid: 40 pid: 997 pub: American Chemical Society artinfo: ui: 44750077 10.1021/ja903997a ppf: 14374 ppct: 7 formats: tig: atl: Unusual Electronic Structure of First Row Transition Metal Complexes Featuring Redox-Active Dipyrromethane Ligands. aug: au: King, Evan R. Betley, Theodore A. affil: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, 306E Mallinckrodt, Cambridge, Massachusetts 02138 su: Electronic structure Transition metals Density functionals Oxidation-reduction reaction Ligands (Chemistry) Arylation Voltammetry sug: subj: Electronic structure Transition metals Density functionals Oxidation-reduction reaction Ligands (Chemistry) Arylation Voltammetry ab: Transition metal complexes (Mn → Zn) of the dipyrromethane ligand, 1,9-dimesityl-5,5-dimethyldipyrromethane (dpm), have been prepared. Arylation of the dpm ligand a to the pyrrolic nitrogen donors limits the accessibility of the pyrrole π-electrons for transition metal coordination, instead forcing η¹,η¹ coordination to the divalent metal series as revealed by X-ray diffraction studies. Structural and magnetic characterization (SQUID, EPR) of the bis-pyridine adducts of (dpm)Mn(py), (dpm)Fe(py), and (dpm)-Copy) reveal each divalent ion to be high-spin and pseudotetrahedral in the solid state, whereas the (dpm)Ni(py) is low-spin and adopts a square-planar geometry. Differential pulse voltammetry on the (dpm)Mi(py) series reveals a common two-electron oxidation pathway that is entirely ligand-based, invariant to the divalent metal-bound, its geometry or spin state within the dpm framework. This latter observation indicates that fully populated ligand-based orbitals from the dpm construct lie above partially filled metal 3d orbitals without intramolecular redox chemistry or spin-state tautomerism occurring. DFT analysis on this family of complexes corroborates this electronic structure assignment, revealing that the highest lying molecular orbitals are completely ligand-based. Chemical oxidation of the deprotonated dpm framework results in the four-electron oxidation of the dipyrrolide framework, although this oxidation product was not observed either in the electrochemical or chemical oxidation of the (dpm)M(py) complexes. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2009 holdings: @attributes: islocal: N |
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