Field-cycling photo-CIDNP MAS NMR

Summary

The solid-state photo-CIDNP effect, discovered in 1994 by Zysmilich and McDermott, has been shown to occur in photosynthetic reaction centers (RCs). To date it has been used in high-field solid-state NMR experiments to explore electronic structures of various RCs. Here we aim to develop this effect into a more generally applicable method for signal enhancement for solid-state NMR spectroscopy. A proposed shuttle system will combine the advantage of low fields, i.e. high nuclear spin-polarization, with the advantage of high field, i.e. high chemical shift dispersion.

We are particularly encouraged to undergo the proposed research because it appears that low fields have an additional advantage: While the high-field effect appears to be limited to photosynthetic RCs, the effect seems to be much more common at lower fields. In fact, the first and only example of a successful experiment on a non-RCs system showing that effect, is recent demonstration on a blue-light photoreceptor at rather low fields (2.4 Tesla). Pioneering experiments on RCs of Rhodobacter (R.) sphaeroides R26 at 1.4 Tesla have shown further enhancement to a factor of more than 80.000. In addition, a new theory predicts high nuclear-spin polarization at earth?s field for many electron transfer systems.

Here we aim to make these sources of nuclear spin-polarization available for high-quality solid-state NMR. The new analytical methodology will allow (i) for re-evaluation of the present theory of the effect, (ii) for obtaining detailed 13C MAS NMR information from various electron transfer systems as well as for (iii) developing photo-CIDNP MAS NMR into a more general applicable method for signal enhancement in solid-state NMR.

Output

Scientific article

  • I Cespedes Camacho, J. Matysik(2014): Spin transport in photosynthesis The BiophysThe Biophysics of Photosynthesis (John Golbeck and Art van der Est, eds.), Springer pp. 141 - 170

Details

Project number

713.012.001

Main applicant

Dr. J. Matysik

Affiliated with

Universität Leipzig, Fakultät für Chemie und Mineralogie, Institut für Analytische Chemie

Team members

Dr. I.F. Céspedes Camacho, Dr. I.F. Céspedes Camacho

Duration

01/08/2012 to 19/05/2016