Molecular Recognition in Mechanochemistry: Insights from Solid-State NMR Spectroscopy

ChemRxiv

Abstract

Molecular-recognition events are highly relevant in biology and chemistry. In the present study, we investigated such processes in the solid state under mechanochemical conditions using the formation of racemic phases upon reacting enantiopure entities as example. As test systems, a-(trifluoromethyl)lactic acid (TFLA) and the amino acids serine and alanine were used. The effects of ball-milling and resonant acoustic mixing (RAM) on the formation of racemic phases were probed by using solid-state Nuclear Magnetic Resonance (NMR) spectroscopy. In a mixer mill, a highly efficient and fast racemic phase formation occurred for both TFLA and the two amino acids. RAM led to the racemic phase for TFLA also, and this process was facilitated upon employing pre-milled enantiopure entities. In contrast, under comparable conditions RAM did not result in the formation of racemic phases for serine and alanine.

Authors 11

1. Calogero Quaranta Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University

2. Igor d’Anciães Almeida Silva

   Max Planck Institute for Chemical Energy Conversion

   Affiliation as printed

   Max Planck Institute for Chemical Energy Conversion

3. Sven Moos Aachen

   Max Planck Institute for Chemical Energy Conversion · RWTH Aachen University

   Affiliation as printed

   Max Planck Institute for Chemical Energy Conversion

   RWTH Aachen University

4. Ettore Bartalucci Aachen

   Max Planck Institute for Chemical Energy Conversion · RWTH Aachen University

   Affiliation as printed

   Max Planck Institute for Chemical Energy Conversion

   RWTH Aachen University

5. Leeroy Hendrickx Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University

6. Benjamin M. D. Fahl Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University

7. Claudia Pasqualini

   University of Siena

   Affiliation as printed

   University of Siena

8. Francesco Puccetti Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University

9. Mirijam Zobel Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University

10. Carsten Bolm Aachen

    RWTH Aachen University

    Affiliation as printed

    RWTH Aachen University

11. Thomas Wiegand Aachen

    Max Planck Institute for Chemical Energy Conversion · RWTH Aachen University

    Affiliation as printed

    Max Planck Institute for Chemical Energy Conversion

    RWTH Aachen University