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

Morrelli, Derek; Guerra, Jacob; Kumar, Prarthana; Bajwa, Bhvandip S.; Krishnan, Viswanathan V; Maitra, Soumyajit

doi:10.1016/j.cplett.2022.139412

Cited by 4 publications

(4 citation statements)

References 26 publications

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“…This notion here is justified from solute–solvent studies using the same analogs in different solvents where Δ S ‡ is extrapolated in an EEC plot and an area of convergence is apparent for the different trends possessing different values for β (see eq ). Thus, the difference in entropy of activation in the series is due to differences in solute–solvent interactions, and we write …”

Section: Discussionmentioning

confidence: 99%

“…The validity of eq , in particular, the influence of external factors such as solvent on β, could be tested further by performing experiments on the same molecule but with different solvents . Based on eq and similar to eq , we could assume that changing the solvent leads to where β sol represents a proportionality constant intrinsic to a solvent and the changes to the thermodynamic parameters are due to solvent–solute interactions.…”

Section: Discussionmentioning

confidence: 99%

“…Based on eq and similar to eq , we could assume that changing the solvent leads to where β sol represents a proportionality constant intrinsic to a solvent and the changes to the thermodynamic parameters are due to solvent–solute interactions. Thus, a single analog will not possess the same Δ H sub ‡ and Δ S sub ‡ from one solvent to another . Δ H int ‡ will be solvent-dependent too, which is logical if one considers the impact of solvent polarity on the magnitude of resonance and inductive effects of substituents.…”

Section: Discussionmentioning

confidence: 99%

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Validation of Enthalpy–Entropy Compensation Mechanism in Partial Amide Bond Rotation

et al. 2020

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The concept of enthalpy–entropy compensation (EEC) is one of the highly debated areas of thermodynamics. The conformational change due to restricted double-bond rotation shows a classic two-site chemical exchange phenomenon and has been extensively studied. Fifty-four analogs of N,N-diethyl-m-toluamide (DEET) as a model system were synthesized to study the thermodynamics of the partial amide bond character using nuclear magnetic resonance (NMR) spectroscopy. Line-shape analysis as a function of temperature is used to estimate the chemical exchange. Eyring analysis was then used to convert the chemical exchange rates to determine the transition state enthalpy and entropy of the molecules. The experimental design follows selective variations that perturb one aspect of the molecular system and its influence on the observed thermodynamic effect. The results of the study demonstrate that amide bond resonance in analogs of DEET follows an EEC mechanism. Simple modifications made to DEET’s structural motif alter both the enthalpy and entropy of the system and were limited overall to a temperature compensation factor, T β = 292.20 K, 95% CI [290.66, 293.73]. We suggest EEC as a model to describe the kinetic compensation seen in chemical exchange phenomena in analogs of DEET.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Validation of Enthalpy–Entropy Compensation Mechanism in Partial Amide Bond Rotation

et al. 2020

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“…A study conducted by Ambrosio et al, has shown that polymeric solutions of PCL with solvents of higher dielectric constant tend to form reduced size diameter fibres [60]. In this study, 4% PU scaffold showed fibres with a diameter double the width compared to 3%/3% PCL/PU scaffolds and higher than 8%/4% PCL/Ge, this may be a result of the use of methanol (Ɛ = 32.7)/chloroform (Ɛ = 4.81) [63] solvent solution in 4% PU scaffolds versus the TFE (Ɛ = 27) used in PCL and PU composite materials [64]. Comparing to the other counterparts, scaffolds derived from 10% PVA demonstrated higher batch variability with decreased quality of nanofibres.…”

Section: Discussionmentioning

confidence: 59%

Fibroblastic tissue growth on polymeric electrospun membranes: a feasibility study

Osório,

Naveenathayalan,

Silva

et al. 2024

Discov Appl Sci

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In recent years the interest in synthetic scaffolds has increased significantly as an alternative to animal-derived materials, as well as the advancement of material and manufacturing engineering, has resulted in improved standardisation and reproducibility within the field. Despite these advancements, a significant amount of research on animal-derived scaffolds, whilst research on synthetic materials is lacking for the growth of non-tumourgenic breast cell lines. The main objective of this work is to manufacture biodegradable scaffolds using biocompatible materials such as PVA (Polyvinyl Alcohol), PU (Polyurethane), Ge (Gelatin) and PCL (Poly-(-caprolactone) to test human cell adhesion and investigate the optimal system that supports representative tissue organisation and that could be used as an alternative to Matrigel™. Here, human mammary fibroblasts (HMF) were used as proof of concept. The membranes were manufactured using the process of electrospinning and characterised by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (ATR-FTIR), contact angle, tensile strength, and degradation studies. The assessment of the membranes as a viable biomaterial for the growth and development of cells was studied by MTT proliferation assay, fluorescence microscopy and SEM imaging. Results demonstrate that all materials are suitable for HMF proliferation. However, from microscopy analysis, only PU and PVA membranes induced morphological organisation of HMF similar to those results obtained in the Matrigel™ control conditions. This feasibility study reveals that HMF organisation, and proliferation are affected by the properties of the scaffold. Consequently, scaffolds parameters should be adjusted and manipulated to impact cell behaviour and emulate in vivo conditions.

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Thermodynamic functions of succinic acid in acetone–water binary mixtures based on computation of KI & KII constants

Amira

Zaghloul

El-Sisy

et al. 2023

Journal of Molecular Liquids

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

Cited by 4 publications

References 26 publications

Validation of Enthalpy–Entropy Compensation Mechanism in Partial Amide Bond Rotation

Validation of Enthalpy–Entropy Compensation Mechanism in Partial Amide Bond Rotation

Fibroblastic tissue growth on polymeric electrospun membranes: a feasibility study

Thermodynamic functions of succinic acid in acetone–water binary mixtures based on computation of KI & KII constants

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