UCL  IRIS
Institutional Research Information Service
UCL Logo
Please report any queries concerning the funding data grouped in the sections named "Externally Awarded" or "Internally Disbursed" (shown on the profile page) to your Research Finance Administrator. Your can find your Research Finance Administrator at http://www.ucl.ac.uk/finance/research/post_award/post_award_contacts.php by entering your department
Please report any queries concerning the student data shown on the profile page to:

Email: portico-services@ucl.ac.uk

Help Desk: http://www.ucl.ac.uk/ras/portico/helpdesk
Publication Detail
trans-Fe-II(H)(2)(diphosphine)(diamine) complexes as alternative catalysts for the asymmetric hydrogenation of ketones? A DFT study
  • Publication Type:
    Journal article
  • Publication Sub Type:
    Article
  • Authors:
    Chen HYT, Di Tommaso D, Hogarth G, Catlow CRA
  • Publisher:
    ROYAL SOC CHEMISTRY
  • Publication date:
    2011
  • Pagination:
    402, 412
  • Journal:
    DALTON T
  • Volume:
    40
  • Issue:
    2
  • Print ISSN:
    1477-9226
  • Language:
    EN
  • Keywords:
    LIGAND BIFUNCTIONAL CATALYSIS, AB-INITIO PSEUDOPOTENTIALS, EFFECTIVE CORE POTENTIALS, ENANTIOSELECTIVE HYDROGENATION, STEREOSELECTIVE HYDROGENATION, MOLECULAR CALCULATIONS, ADJUSTABLE-PARAMETERS, TRANSITION-ELEMENTS, CARBONYL-COMPOUNDS, PROCHIRAL KETONES
  • Addresses:
    Chen, HYT
    UCL
    Dept Chem
    London
    WC1E 6BT
    England
Abstract
New insights into the structural, electronic and catalytic properties of Fe complexes are provided by a density functional theory study of model as well as real [Fe-II(H)(2)(diphosphine)(diamine)] systems. Calculations conducted using several different functionals on the trans- and cis-isomers of [Fe-II(H)(2)(S-xylbinap)(S,S-dpen)] complexes show that, as with the [Ru-II(H)(2)(diphosphine)(diamine)] complexes, the trans-[Fe-II(H)(2)(diphosphine)(diamine)] complex is the more stable isomer. Analysis of the spin states of the trans-[Fe-II(H)(2)(diphosphine)(diamine)] complexes also shows that the singlet state is significantly more stable than the triplet and the quintet, as with the [Ru-II(H)(2)(diphosphine)(diamine)] complexes. Calculations of the catalytic cycle for the hydrogenation of ketones using two model trans-[M-II(H)(2)(PH3)(2)(en)] catalysts, where M = Ru and Fe, show that the mechanism of reaction as well as the activation energies are very similar, in particular: (i) the ketone/alcohol hydrogen transfer reaction occurs through the metal-ligand bifunctional mechanism, with energy barriers of 3.4 and 3.2 kcal mol(-1) for the Ru- and Fe-catalysed reactions, respectively; (ii) the heterolytic splitting of H-2 across the M(sic)N bond for the regeneration of the Ru and Fe catalysts has an activation barrier of 13.8 and 12.8 kcal mol(-1), respectively, and is expected to be the rate determining step for both catalytic systems. The reduction of acetophenone by trans-[M-II(H)(2)(S-xylbinap)(S,S-dpen)] complexes along two competitive reaction pathways, shows that the intermediates for the Fe catalytic system are similar to those responsible for the high enantioselectivity of (R)-alcohol in those proposed trans-[Ru-II(H)(2)(S-xylbinap)(S,S-dpen)] catalysed acetophenone hydrogenation reaction. Thus the high enantiomeric excess in the hydrogenation of acetophenone could, in principle, be achieved using Fe catalysts.
Publication data is maintained in RPS. Visit https://rps.ucl.ac.uk
 More search options
UCL Researchers
Author
Dept of Chemistry
University College London - Gower Street - London - WC1E 6BT Tel:+44 (0)20 7679 2000

© UCL 1999–2011

Search by