Hydrogen-Bond Acceptor Properties of Nitro-O Atoms : A Combined Crystallographic Database and Ab Initio Molecular Orbital Study
(1997) In Acta Crystallographica Section B: Structural Science 53(6). p.1017-1024- Abstract
Crystallographic data for 620 C - nitro-O⋯H - N,O hydrogen bonds, involving 560 unique H atoms, have been investigated to the van der Waals limit of 2.62 Å. The overall mean nitro-O⋯H bond length is 2.30 (1) Å, which is much longer (weaker) than comparable hydrogen bonds involving >C=O acceptors in ketones, carboxylic acids and amides. The donor hydrogen prefers to approach the nitro-O atoms in the C - NO2 plane and there is an approximate 3:2 preference for hydrogen approach between the two nitro-O atoms, rather than between the C and O substituents. However, hydrogen approach between the two O acceptors is usually strongly asymmetric, the H atom being more closely associated with one of the O atoms: only 60 H atoms have... (More)
Crystallographic data for 620 C - nitro-O⋯H - N,O hydrogen bonds, involving 560 unique H atoms, have been investigated to the van der Waals limit of 2.62 Å. The overall mean nitro-O⋯H bond length is 2.30 (1) Å, which is much longer (weaker) than comparable hydrogen bonds involving >C=O acceptors in ketones, carboxylic acids and amides. The donor hydrogen prefers to approach the nitro-O atoms in the C - NO2 plane and there is an approximate 3:2 preference for hydrogen approach between the two nitro-O atoms, rather than between the C and O substituents. However, hydrogen approach between the two O acceptors is usually strongly asymmetric, the H atom being more closely associated with one of the O atoms: only 60 H atoms have both O⋯H distances ≤ 2.62 Å. The approach of hydrogen along putative O-atom lone-pair directions is clearly observed. Ab-initio-based molecular orbital calculations (6-31G** basis set level), using intermolecular perturbation theory (IMPT) applied to the nitromethane-methanol model dimer, agree with the experimental observations. IMPT calculations yield an attractive hydrogen-bond energy of ca -15 kJ mol-1, about half as strong as the >C=O⋯H bonds noted above.
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- author
- Allen, Frank H. ; Baalham, Christine A. ; Lommerse, Jos P.M. ; Raithby, Paul R. and Sparr, Emma LU
- publishing date
- 1997-12-01
- type
- Contribution to journal
- publication status
- published
- in
- Acta Crystallographica Section B: Structural Science
- volume
- 53
- issue
- 6
- pages
- 8 pages
- publisher
- Wiley-Blackwell
- external identifiers
-
- scopus:0000872589
- ISSN
- 0108-7681
- DOI
- 10.1107/S0108768197010239
- language
- English
- LU publication?
- no
- id
- ae594e29-11fb-45dd-b23e-ce74e33c2415
- date added to LUP
- 2023-12-07 14:49:48
- date last changed
- 2023-12-08 10:30:29
@article{ae594e29-11fb-45dd-b23e-ce74e33c2415, abstract = {{<p>Crystallographic data for 620 C - nitro-O⋯H - N,O hydrogen bonds, involving 560 unique H atoms, have been investigated to the van der Waals limit of 2.62 Å. The overall mean nitro-O⋯H bond length is 2.30 (1) Å, which is much longer (weaker) than comparable hydrogen bonds involving >C=O acceptors in ketones, carboxylic acids and amides. The donor hydrogen prefers to approach the nitro-O atoms in the C - NO<sub>2</sub> plane and there is an approximate 3:2 preference for hydrogen approach between the two nitro-O atoms, rather than between the C and O substituents. However, hydrogen approach between the two O acceptors is usually strongly asymmetric, the H atom being more closely associated with one of the O atoms: only 60 H atoms have both O⋯H distances ≤ 2.62 Å. The approach of hydrogen along putative O-atom lone-pair directions is clearly observed. Ab-initio-based molecular orbital calculations (6-31G** basis set level), using intermolecular perturbation theory (IMPT) applied to the nitromethane-methanol model dimer, agree with the experimental observations. IMPT calculations yield an attractive hydrogen-bond energy of ca -15 kJ mol<sup>-1</sup>, about half as strong as the >C=O⋯H bonds noted above.</p>}}, author = {{Allen, Frank H. and Baalham, Christine A. and Lommerse, Jos P.M. and Raithby, Paul R. and Sparr, Emma}}, issn = {{0108-7681}}, language = {{eng}}, month = {{12}}, number = {{6}}, pages = {{1017--1024}}, publisher = {{Wiley-Blackwell}}, series = {{Acta Crystallographica Section B: Structural Science}}, title = {{Hydrogen-Bond Acceptor Properties of Nitro-O Atoms : A Combined Crystallographic Database and <i>Ab Initio</i> Molecular Orbital Study}}, url = {{http://dx.doi.org/10.1107/S0108768197010239}}, doi = {{10.1107/S0108768197010239}}, volume = {{53}}, year = {{1997}}, }