The pKa rule in light of local mode force constants

Quintano, Mateus; Moura, Renaldo T.; Kraka, Elfi

doi:10.1016/j.cplett.2023.140654

Cited by 17 publications

(1 citation statement)

References 37 publications

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“…The difference in p K a between RNL (p K a = 7.2) 48 and NTG (p K a = 3.1) 49 is 4.1. According to the p K a rule (p K a,base − p K a,acid = Δp K a > 3 indicates salt formation), 50 this difference is high enough to lead to the formation of a co-amorphous salt via ionic interactions between NTG and RNL . As typical of co-amorphous salts, 51 their glass transition temperatures are higher than what is found for pure components.…”

Section: Resultsmentioning

confidence: 99%

Avoiding pits on the energy landscape – alternative strategies for stabilizing nateglinide co-amorphous systems

Silva,

Jasiurkowska-Delaporte,

Pereira Silva

et al. 2024

CrystEngComm

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Section: Resultsmentioning

confidence: 99%

Avoiding pits on the energy landscape – alternative strategies for stabilizing nateglinide co-amorphous systems

Silva,

Jasiurkowska-Delaporte,

Pereira Silva

et al. 2024

CrystEngComm

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The Hydrogen‐Bond Continuum in the Salt/Cocrystal Systems of Quinoline and Chloro‐Nitrobenzoic Acids

Radek Štoček,

Blahut,

Chalupná

et al. 2024

Chemistry A European J

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This study investigates the hydrogen‐bond geometry in six two‐component solid systems composed of quinoline and chloro‐nitrobenzoic acids. New X‐ray diffraction studies were conducted using both the conventional independent‐atom model and the more recent Hirshfeld atom‐refinement method, with the latter providing precise hydrogen‐atom positions. The systems can be divided into salts (the hydrogen atom transferred to the quinoline nitrogen), cocrystals (the hydrogen atom retained by the acid), and intermediate structures. Solid‐state NMR experiments corroborated the X‐ray diffraction‐derived H–N distances. DFT calculations, using five functionals including hybrid B3LYP and PBE0, showed varying energy profiles for the hydrogen bonds, with notable differences across functionals. These calculations revealed different preferences for salt or cocrystal structures, depending on the functional used. Path‐integral molecular dynamics simulations incorporating nuclear quantum effects demonstrated significant hydrogen‐atom delocalization, forming a hydrogen‐bond continuum, and provided average N–H distances in excellent agreement with experimental results. This comprehensive experimental and theoretical approach highlights the complexity of multicomponent solids. The study emphasizes that the classification into salts or cocrystals is frequently inadequate, as the hydrogen atom is often significantly delocalized in the hydrogen bond. This insight is crucial for understanding and predicting the behavior of such systems in pharmaceutical applications.

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Chemical Bond Overlap Descriptors From Multiconfiguration Wavefunctions

Santos‐Jr,

Kraka,

Moura

2024

J Comput Chem

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The chemical bond is a fundamental concept in chemistry, and various models and descriptors have evolved since the advent of quantum mechanics. This study extends the overlap density and its topological descriptors (OP/TOP) to multiconfigurational wavefunctions. We discuss a comparative analysis of OP/TOP descriptors using CASSCF and DCD‐CAS(2) wavefunctions for a diverse range of molecular systems, including X–O bonds in X–OH (XH, Li, Na, H2B, H3C, H2N, HO, F) and Li–X′ (XF, Cl, and Br). Results show that OP/TOP aligns with bonding models like the quantum theory of atoms in molecules (QTAIM) and local vibrational modes theory, revealing insights such as overlap densities shifting towards the more electronegative atom in polar bonds. The Li–F dissociation profile using OP/TOP descriptors demonstrated sensitivity to ionic/neutral inversion during Li–F dissociation, highlighting their potential for elucidating complex bond phenomena and offering new avenues for understanding multiconfigurational chemical bond dynamics.

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The pKa rule in light of local mode force constants

Cited by 17 publications

References 37 publications

Avoiding pits on the energy landscape – alternative strategies for stabilizing nateglinide co-amorphous systems

Avoiding pits on the energy landscape – alternative strategies for stabilizing nateglinide co-amorphous systems

The Hydrogen‐Bond Continuum in the Salt/Cocrystal Systems of Quinoline and Chloro‐Nitrobenzoic Acids

Chemical Bond Overlap Descriptors From Multiconfiguration Wavefunctions

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