Solid-state (55)Mn NMR spectroscopy of bis(μ-oxo)dimanganese(IV) [Mn(2)O(2)(salpn)(2)], a model for the oxygen evolving complex in photosystem II

J Am Chem Soc. 2010 Dec 1;132(47):16727-9. doi: 10.1021/ja1054252. Epub 2010 Nov 8.

Abstract

We have examined the antiferromagneticly coupled bis(μ-oxo)dimanganese(IV) complex [Mn(2)O(2)(salpn)(2)] (1) with (55)Mn solid-state NMR at cryogenic temperatures and first-principle theory. The extracted values of the (55)Mn quadrupole coupling constant, C(Q), and its asymmetry parameter, η(Q), for 1 are 24.7 MHz and 0.43, respectively. Further, there was a large anisotropic contribution to the shielding of each Mn(4+), i.e. a Δσ of 3375 ppm. Utilizing broken symmetry density functional theory, the predicted values of the electric field gradient (EFG) or equivalently the C(Q) and η(Q) at ZORA, PBE QZ4P all electron level of theory are 23.4 MHz and 0.68, respectively, in good agreement with experimental observations.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Biomimetic Materials / chemistry*
  • Magnetic Resonance Spectroscopy / methods*
  • Manganese Compounds / chemistry*
  • Models, Molecular
  • Molecular Conformation
  • Organometallic Compounds / chemistry*
  • Oxides / chemistry*
  • Oxygen / metabolism*
  • Photosystem II Protein Complex / metabolism*
  • Temperature

Substances

  • Manganese Compounds
  • Organometallic Compounds
  • Oxides
  • Photosystem II Protein Complex
  • manganese oxide
  • Oxygen