Abstract
The effects of high pressure and low temperature have been explored on the 'orange-plate' (OP) form of the highly-polymorphic 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile molecular crystal structures. Neutron powder and single-crystal diffraction measured up to 9.3 GPa and 40 K, respectively, show that the crystal structure is robust, retaining P21/n symmetry over the pressure and temperature range studied, even though it is revealed to be quite soft, having a bulk modulus of 4.3(3) GPa. Intermolecular and lattice energies become progressively less favourable with pressure, relative to the thermodynamically-stable 'yellow' (Y, P21/n) form, showing that the kinetic barriers to transformation, stabilising the material, persist from ambient to extreme conditions.
| Original language | English |
|---|---|
| Pages (from-to) | 4473-4483 |
| Number of pages | 11 |
| Journal | CrystEngComm |
| Volume | 21 |
| Issue number | 30 |
| DOIs | |
| State | Published - 2019 |
| Externally published | Yes |
Funding
We thank Dr Dominic Fortes for assistance with the DFT calculations, Dr Andrew Bond for guidance with process PIXEL, and ISIS and STFC for providing access to the PEARL and SXD instruments. Computing resources were provided by the STFC Scientific Computing Department's SCARF cluster.