TU Darmstadt / ULB / TUbiblio

Revealing the configuration and crystal packing of organic compounds by solid-state NMR spectroscopy: Methoxycarbonylurea, a case study

Macholl, S. and Börner, F. and Buntkowsky, G. (2004):
Revealing the configuration and crystal packing of organic compounds by solid-state NMR spectroscopy: Methoxycarbonylurea, a case study.
In: Chemistry-a European Journal, 10 (19), pp. 4808-4816, [Online-Edition: http://apps.webofknowledge.com/full_record.do?product=WOS&se...],
[Article]

Abstract

The molecular configuration and intermolecular arrangement of polycrystalline methoxycarbonylurea (MCU) has been studied by a combination of chemical editing, rotational echo double resonance (REDOR) spectroscopy and ab initio calculations. From the multispin ISn REDOR experiments several dipolar couplings were determined and converted into distance constraints. Intra- and intermolecular dipolar couplings were distinguished by isotope dilution. The configuration of the MCU molecule can be determined from three torsion angles Psi(1), Psi(2), and Psi(3). Ab initio calculations showed that these angles are either 0degrees or 180degrees (Z or E). From the REDOR experiments, the E configuration was found for Psi(1) and Psi(2) and the Z configuration for Psi(3). Thus the configuration of MCU in the solid state was determined to be EEZ. Distance constraints for the intermolecular arrangement of MCU were obtained by performing REDOR experiments on (CN2)-C-13-N-15 MCU with different degrees of isotope dilution and on a cocrystallized 1:1 mixture of C-13(urea) MCU and N-15(amide) MCU. By combining these distance constraints with molecular modeling, three different possible packing motifs for MCU molecules were found. The molecules in these motifs are arranged as linear chains with methoxy groups at the borders of the chains. All the intermolecular hydrogen bond donors and acceptors in the interior of the chain are saturated.

Item Type: Article
Erschienen: 2004
Creators: Macholl, S. and Börner, F. and Buntkowsky, G.
Title: Revealing the configuration and crystal packing of organic compounds by solid-state NMR spectroscopy: Methoxycarbonylurea, a case study
Language: English
Abstract:

The molecular configuration and intermolecular arrangement of polycrystalline methoxycarbonylurea (MCU) has been studied by a combination of chemical editing, rotational echo double resonance (REDOR) spectroscopy and ab initio calculations. From the multispin ISn REDOR experiments several dipolar couplings were determined and converted into distance constraints. Intra- and intermolecular dipolar couplings were distinguished by isotope dilution. The configuration of the MCU molecule can be determined from three torsion angles Psi(1), Psi(2), and Psi(3). Ab initio calculations showed that these angles are either 0degrees or 180degrees (Z or E). From the REDOR experiments, the E configuration was found for Psi(1) and Psi(2) and the Z configuration for Psi(3). Thus the configuration of MCU in the solid state was determined to be EEZ. Distance constraints for the intermolecular arrangement of MCU were obtained by performing REDOR experiments on (CN2)-C-13-N-15 MCU with different degrees of isotope dilution and on a cocrystallized 1:1 mixture of C-13(urea) MCU and N-15(amide) MCU. By combining these distance constraints with molecular modeling, three different possible packing motifs for MCU molecules were found. The molecules in these motifs are arranged as linear chains with methoxy groups at the borders of the chains. All the intermolecular hydrogen bond donors and acceptors in the interior of the chain are saturated.

Journal or Publication Title: Chemistry-a European Journal
Volume: 10
Number: 19
Uncontrolled Keywords: configuration determination hydrogen bonds molecular packing nmr crystallography redor double-resonance nmr chemical-shift nmr rotational-echo distance determinations molecular-packing spin pairs redor couplings peptide density
Divisions: 07 Department of Chemistry
07 Department of Chemistry > Physical Chemistry
Date Deposited: 27 Oct 2014 20:45
Official URL: http://apps.webofknowledge.com/full_record.do?product=WOS&se...
Additional Information:

860QC Times Cited:12 Cited References Count:49

Export:
Suche nach Titel in: TUfind oder in Google
Send an inquiry Send an inquiry

Options (only for editors)
Show editorial Details Show editorial Details