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Seven multi-component molecular crystals containing O-H⋯O/O+-H⋯O- and N+-H⋯O- short strong hydrogen bonds (SSHBs) have been engineered by combining substituted organic acids with hydrogen bond acceptor molecules N,N-dimethylurea and isonicotinamide. In these materials, the shortest of the SSHBs are formed in the N,N-dimethylurea set for the ortho/para nitro-substituted organic acids whilst a twisted molecular approach favours the shorter SSHBs N+-H⋯O- in the isonicotinamide set. Temperature dependent proton migration behaviour has been explored in these systems using single crystal synchrotron X-ray diffraction (SCSXRD). By using a protocol which considers a combination of structural information when assessing the hydrogen atom (H-atom) behaviour, including refined H-atom positions alongside heavy atom geometry and Fourier difference maps, temperature dependent proton migration is indicated in two complexes (2: N,N-dimethylurea 2,4-dinitrobenzoic acid 1 : 1 and 5: isonicotinamide phthalic acid 2 : 1). We also implement Hirshfeld atom refinement for further confidence in this observation; this highlights the importance of having corroborating trends when applying the SCSXRD technique in these studies. Further insights into the SSHB donor-acceptor distance limit for temperature dependent proton migration are also revealed. For the O-H⋯O/O+-H⋯O- SSHBs, the systems here support the previously proposed maximum limit of 2.45 Å whilst for the charge assisted N+-H⋯O- SSHBs, a limit in the region of 2.55 Å may be suggested.
|Number of pages||12|
|Early online date||12 Aug 2019|
|Publication status||Published - 21 Sept 2019|
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
FingerprintDive into the research topics of 'Exploring short strong hydrogen bonds engineered in organic acid molecular crystals for temperature dependent proton migration behaviour using single crystal synchrotron X-ray diffraction (SCSXRD)'. Together they form a unique fingerprint.
- 1 Finished
Applying Long-Lived Metastable States in Switchable Functionality via Kinetic Control of Molecular Assembly
Raithby, P., Burrows, A., Carbery, D., Marken, F., Parker, S., Walsh, A. & Wilson, C.
Engineering and Physical Sciences Research Council
1/11/12 → 30/04/18
Project: Research council