Role of solvent dielectric constant on the enthalpy-entropy compensation in the hindered amide bond rotation

Derek Morrelli, Jacob G. Guerra, Prarthana Kumar, Bhvandip Bajwa, V. V. Krishnan, Santanu Maitra

Research output: Contribution to journalArticlepeer-review

Abstract

The purpose of this investigation is to determine if enthalpy-entropy compensation (EEC) is a valid concept when the experiments are performed on a set of molecules in multiple solvents. Dynamic nuclear magnetic resonance (DNMR) experiments are performed on a series of analogs derived from N, N-diethyl-m-toluamide (DEET) in six different solvents of varying dielectric constant from toluene‑d8 (ε = 2.38) to dimethyl sulfoxide-d6 (ε = 46.7). The thermodynamic parameters of the restricted rotation to the solvent dielectric constant do not have a straightforward correlation relationship between them. However, the activation enthalpy and entropy of more than sixty different experimental measurements indicate that enthalpy-entropy compensation (EEC) is independent of the solvent condition with a compensation temperature of 287.81 ± 3.95 K. The results, therefore, support the broader role of EEC on the partial amide bond dynamics in the DEET analogs over the temperature range studied.

Original languageEnglish (US)
Article number139412
JournalChemical Physics Letters
Volume792
DOIs
StatePublished - Apr 2022

Keywords

  • Dielectric constant
  • Enthalpy-entropy compensation
  • Nuclear Magnetic Resonance (NMR)
  • Partial double bond
  • Solvents

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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