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Lecture

Towards Understanding Silica-Biomineralization: Solid-state NMR Spectroscopy, DNP Investigations, and MD Simulations of the Organic/Inorganic Interface in Silica Biohybrids

Wednesday (10.05.2017)
10:20 - 10:40
Part of:


Organic / inorganic interfaces play a key role in catalytic processes, separation science, materials science, and biomineralization. Our recent studies on diatom biosilica using DNP[1] and 1H-13C-{29Si}-REDOR[2] provide information about the supramolecular organization at the interface and peptide secondary structure. Functional groups in close contact with silica were identified in diatom biosilica. For fully isotope-labeled biosilica, distance determination by REDOR is complicated by strongly overlapping signals.[2] Distances and spin system geometries can now be evaluated and verified using our well defined synthetic model systems employing selective isotope labeling. For example choline-silica nanocomposites exhibit experimental 1H-13C-{29Si}-REDOR fractions up to about 30 % and changes in 13C chemical shift for strongly silica-adsorbed 13C1-Choline. This indicates the formation of hydrogen bonds between the choline C1-OH and ionized silanol groups at the silica surface, which is verified by MD simulations and 1H-29Si-1H Double CP (DCP) experiments. The latter also show close contact of the choline methyl protons to the silica. [3] Furthermore, nanocomposites containing silica and selectively 13C and 15N labeled long chain polyamines (LPCA) of similar structure as found in diatoms were prepared. Precise REDOR curves reveal valuable information about interactions of the LPCA with the silica surface. [4] The corresponding triple resonance experiments on samples synthesized with sodium metasilicate of variable 29Si content result in additional distance and spin system information.


[1] Jantschke et al. Angew. Chem. Int. Ed. 54 (2015) 15069-15073

[2] Wisser et al. Solid State Nucl. Magn. Reson. 66/67 (2015) 33-39

[3] Brückner et al. Langmuir, 32 (2016), 11698–11705

[4] Abacilar et al. RSC Adv. 6 (2016) 93343-93348

 

Speaker:
Additional Authors:
  • Dr. Sergii Donets
    TU Dresden
  • Dr. Maryna Abacilar
    Philipps-Universität Marburg
  • Dr. Anne Jantschke
    TU Dresden
  • Dr. Eline Koers
    Utrecht University
  • Prof. Dr. Armin Geyer
    Philipps-Universität Marburg
  • Dr. Rafael Gutiérrez
    TU Dresden
  • Prof. Dr. Marc Baldus
    Utrecht University
  • Prof. Dr. Eike Brunner
    TU Dresden