A Karplus Equation for the Conformational Analysis of Organic Molecular Crystals

Pierre Thureau (1) , Isaure Carvin (1) , Fabio Ziarelli (2) , Stéphane S Viel (1, 3) , Giulia Mollica (1)

1 ICR - Institut de Chimie Radicalaire
2 FSCM - Fédération des Sciences Chimiques de Marseille
3 IUF - Institut universitaire de France

Vicinal scalar couplings (3 J) are extensively used for the conformational analysis of organic compounds in the liquid state through empirical Karplus equations.I nc ontrast, there are no examples of such use for the structural investigation of solids.W ith the support of first principles calculations,wedemonstrate here that 13 C-13 C 3 Jcoupling constants (3 J CC)measured on aseries of isotopically enriched solid amino acids and sugars can be related to dihedral angles by asimple Karplus-like relationship,a nd we provide ap arameterized Karplus function for the conformational analysis of organic molecular crystals.U nder the experimental conditions discussed, torsional angles can be estimated from the experimental 3 J CC values with an accuracy of 108 8 using this function. These results open new perspectives towardsthe use of 3 J CC as anew analytical tool that could considerably simplify structure determination of functional organic solids.

Domaines: Chimie théorique et/ou physique

Pierre Thureau, Isaure Carvin, Fabio Ziarelli, Stéphane S Viel, Giulia Mollica. A Karplus Equation for the Conformational Analysis of Organic Molecular Crystals. Angewandte Chemie International Edition, 2019, 58 (45), pp.16047-16051. ⟨10.1002/anie.201906359⟩. ⟨hal-02354508⟩