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Updated: Aug 6, 2026
05:51
Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
Published on: July 19, 2019
Origins of isotopomeric polymorphism
Jun Zhou1, Young-Sik Kye, Alexander I Kolesnikov
1Department of Chemistry, University of Nebraska at Lincoln, 723, Hamilton Hall, Lincoln, NE 68588-0304, USA.
Isotopes in Environmental and Health Studies
|July 28, 2006
Summary
Isotopomers of 4-methylpyridine and pentachlorophenol (4MPPCP) exhibit isotopomeric polymorphism, forming different crystal structures. This occurs due to variations in hydrogen bonding and zero-point energies between protonated and deuterated forms.
Area of Science:
- Solid-state chemistry
- Crystallography
- Physical chemistry
Background:
- The 4-methylpyridine and pentachlorophenol (4MPPCP) complex exhibits polymorphism.
- Isotopic substitution can influence crystal structure and stability.
Purpose of the Study:
- To investigate the phenomenon of isotopomeric polymorphism in the 4MPPCP complex.
- To elucidate the role of hydrogen bonding and zero-point energies in determining crystal structure stability.
Main Methods:
- Synthesis of 4MPPCP complex with varying levels of deuteration.
- Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy.
- Inelastic neutron scattering (INS).
Main Results:
- Deuterated 4MPPCP forms a different monoclinic polymorph compared to the triclinic polymorph of protonated 4MPPCP.
- Hydrogen bonding differences and low-lying vibrational modes in the triclinic form contribute to isotopomeric effects.
- Zero-point energy differences between protonated and deuterated forms explain the observed changes in relative stability.
Conclusions:
- Isotopomeric polymorphism in 4MPPCP is driven by differences in hydrogen bond characteristics and their associated zero-point energies.
- The study provides a molecular-level understanding of how isotopic substitution affects crystal engineering and material properties.
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