Hydrogen-bond directionality and symmetry in [C(O)NH](N)(2)P(O)-based structures: a comparison between X-ray crystallography data and neutron-normalized values, and evaluation of reliability
| Authors | |
|---|---|
| Year of publication | 2021 |
| Type | Article in Periodical |
| Magazine / Source | Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials |
| MU Faculty or unit | |
| Citation | |
| Web | https://doi.org/10.1107/S2052520621003371 |
| Doi | http://dx.doi.org/10.1107/S2052520621003371 |
| Keywords | phosphoric triamide; X-ray diffraction; neutron normalization; symmetry; Cambridge Structural Database; lone electron pair |
| Description | For [C(O)NH](N)2P(O)-based structures, the magnitude of the differences in the N—H?O, H?O=P and H?O=C angles has been evaluated when the N—H bond lengths, determined by X-ray diffraction, were compared to the neutron normalized values and the maximum percentage difference was obtained, i.e. about 3% for the angle even if the N—H bond lengths have a difference of about 30% (0.7 A for the X-ray and 1.03 A for the neutron-normalized value). The symmetries of the crystals are discussed with respect to the symmetry of the molecules, as well as to the symmetry of hydrogen-bonded motifs, and the role of the most directional hydrogen bond in raising the probability of obtaining centrosymmetric crystal structures is investigated. The work was performed by considering nine new X-ray crystal structures and 204 analogous structures retrieved from the Cambridge Structural Database. |
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