TY - JOUR
T1 - Structural Evolution of Trimethylacetonitrile under Pressure
T2 - A Combined X-ray Diffraction and Computational Study
AU - Blake, Rebecca M.
AU - Stapleton, Nicholas D.
AU - Jones, Isabelle M.
AU - Brookes, James R.
AU - Turner, Gemma F.
AU - Bird, Stephanie A.
AU - Riboldi-Tunnicliffe, Alan
AU - Williamson, Rachel M.
AU - Young, Rosemary
AU - Maynard-Casely, Helen E.
AU - Spagnoli, Dino
AU - Moggach, Stephen A.
N1 - Publisher Copyright:
© 2024 American Chemical Society.
PY - 2024/9/19
Y1 - 2024/9/19
N2 - Three high-pressure phases of trimethylacetonitrile, a compound of potential interest in the context of Titan’s atmospheric chemistry, have been investigated using single-crystal X-ray diffraction, periodic density functional theory, and CrystalExplorer intermolecular energy calculations. A disordered tetragonal P4/nmm phase is formed between 0.07 and 0.29 GPa (denoted hp-I). Compression to 0.43 GPa forms an ordered orthorhombic Pnma phase (hp-II), which transforms to a monoclinic P21/m phase (hp-III) at 1.52 GPa. The hp-III phase persists to at least 3.34 GPa. Phase transitions are driven by densification of the crystal and facilitated by rearrangement of the supramolecular hydrogen-bonding network, with 180° reorientation of half the molecules. Compression of each phase is associated with slight shortening of the intermolecular hydrogen bonds, with gradual destabilization of the cohesive energy to 3.34 GPa.
AB - Three high-pressure phases of trimethylacetonitrile, a compound of potential interest in the context of Titan’s atmospheric chemistry, have been investigated using single-crystal X-ray diffraction, periodic density functional theory, and CrystalExplorer intermolecular energy calculations. A disordered tetragonal P4/nmm phase is formed between 0.07 and 0.29 GPa (denoted hp-I). Compression to 0.43 GPa forms an ordered orthorhombic Pnma phase (hp-II), which transforms to a monoclinic P21/m phase (hp-III) at 1.52 GPa. The hp-III phase persists to at least 3.34 GPa. Phase transitions are driven by densification of the crystal and facilitated by rearrangement of the supramolecular hydrogen-bonding network, with 180° reorientation of half the molecules. Compression of each phase is associated with slight shortening of the intermolecular hydrogen bonds, with gradual destabilization of the cohesive energy to 3.34 GPa.
KW - density functional theory
KW - high pressure
KW - small molecule
KW - Titan
KW - X-ray crystallography
UR - http://www.scopus.com/inward/record.url?scp=85202203036&partnerID=8YFLogxK
U2 - 10.1021/acsearthspacechem.4c00202
DO - 10.1021/acsearthspacechem.4c00202
M3 - Article
AN - SCOPUS:85202203036
SN - 2472-3452
VL - 8
SP - 1693
EP - 1699
JO - ACS Earth and Space Chemistry
JF - ACS Earth and Space Chemistry
IS - 9
ER -