ISIS Neutron and Muon Source Data Journal

Thermodynamic Control of Isotopic Polymorphism

Abstract: Co-crystals of 4-methylpyridine and pentachlorophenol (MP-PCP) exhibit the very unusual property of isotopic polymorphism, formation of different phases by samples differing only in isotopic composition. Isotopically normal MP and PCP co-crystals are triclinic, but when the phenolic oxygen is deuterated, the structure is monoclinic. The triclinic deuterated and the isotopically normal monoclinic phases have not been described. Statistical thermodynamic modelling based on DFT calculations indicates that the triclinic deuterated form should become competitive at low temperature, and this has been confirmed by crystal growth at 243 K which yields a mixed monoclinic and triclinic sample. The aim of this proposal is to follow crystal growth of this form by in situ by neutron powder diffraction, confirming the calculations and obtaining unambiguously phase pure sample of the triclinic deuter

Principal Investigator: Professor Simon Parsons
Local Contact: Dr Ronald Smith
Experimenter: Dr Nicholas Funnell

DOI: 10.5286/ISIS.E.RB1620117

ISIS Experiment Number: RB1620117

Publisher: STFC ISIS Neutron and Muon Source

Data format: RAW/Nexus
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Data Citation

The recommended format for citing this dataset in a research publication is as:
[author], [date], [title], [publisher], [doi]

For Example:
Professor Simon Parsons et al; (2016): Thermodynamic Control of Isotopic Polymorphism, STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB1620117

Data is released under the CC-BY-4.0 license.