Enthalpies of Adduct Formation between Boron Trifluoride and Selected Organic Bases in Solution: Toward an Accurate Theoretical Entry to Lewis Basicity

10.20944/preprints202110.0050.v1 ◽

2021 ◽

Author(s):

Jean-François Gal ◽

Pierre-Charles Maria ◽

Manuel Yáñez ◽

Otilia Mó

Keyword(s):

Hydrogen Bonding ◽

Uncertain Data ◽

Adduct Formation ◽

Lewis Base ◽

Solvation Model ◽

Specific Solvation ◽

Lewis Bases ◽

Organic Bases ◽

Experimental Values ◽

High Level

The Lewis basicity of selected organic bases, modeled by the enthalpies of adduct formation between gaseous BF3 and the bases in dichloromethane (DCM) solution, is critically examined. Although experimental enthalpies for a large number of molecules have been reported in the literature, it may be desirable to estimate missing or uncertain data for important Lewis bases. We have decided to use high-level ab initio procedures, combined with a polarized continuum solvation model, in which the solvated species are the clusters formed by specific hydrogen bonding of DCM with the Lewis base and the Lewis base/BF3 adduct. This mode of interaction with DCM corresponds to a specific solvation model (SSM). The results actually show that the enthalpy of BF3 adduct formation in DCM solution is clearly influenced by specific interactions, DCM acting as hydrogen-bonding donor (HBD) molecule in two ways: base/DCM and adduct/DCM, confirming that specific solvation is an important contribution to experimentally determined Lewis basicity scales. This analysis allows us to conclude that there are reasons to suspect some gas-phase values to be in error by more than the stated experimental uncertainty. Some experimental values in DCM solution that were uncertain because of identified reasons can be complemented by the computed values.

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Polymeric carbon Lewis base–acid adducts: poly(NHC–C60)

Polymer Chemistry ◽

10.1039/c4py01488j ◽

2015 ◽

Vol 6 (10) ◽

pp. 1741-1750 ◽

Cited By ~ 4

Author(s):

Miao Hong ◽

Eugene Y.-X. Chen

Keyword(s):

Adduct Formation ◽

Lewis Base ◽

Lewis Bases ◽

Polymeric Carbon

Polymers with high C60 incorporations and intriguing properties are conveniently synthesized via adduct formation between polymeric Lewis bases and C60.

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DFT Benchmark Study of the O--O Bond Dissociation Energy in Peroxides Validated with High-Level Ab-Initio Calculations

10.26434/chemrxiv.8217221.v1 ◽

2019 ◽

Author(s):

Danilo Carmona ◽

Pablo Jaque ◽

Esteban Vöhringer-Martinez

Keyword(s):

Reference Value ◽

Basis Set ◽

Basis Sets ◽

Mean Deviation ◽

Bond Dissociation ◽

Dissociation Energies ◽

The Mean ◽

Experimental Values ◽

High Level ◽

Almost All

<div><div><div><p>Peroxides play a central role in many chemical and biological pro- cesses such as the Fenton reaction. The relevance of these compounds lies in the low stability of the O–O bond which upon dissociation results in radical species able to initiate various chemical or biological processes. In this work, a set of 64 DFT functional-basis set combinations has been validated in terms of their capability to describe bond dissociation energies (BDE) for the O–O bond in a database of 14 ROOH peroxides for which experimental values ofBDE are available. Moreover, the electronic contributions to the BDE were obtained for four of the peroxides and the anion H2O2− at the CBS limit at CCSD(T) level with Dunning’s basis sets up to triple–ζ quality provid- ing a reference value for the hydrogen peroxide anion as a model. Almost all the functionals considered here yielded mean absolute deviations around 5.0 kcal mol−1. The smallest values were observed for the ωB97 family and the Minnesota M11 functional with a marked basis set dependence. Despite the mean deviation, order relations among BDE experimental values of peroxides were also considered. The ωB97 family was able to reproduce the relations correctly whereas other functionals presented a marked dependence on the chemical nature of the R group. Interestingly, M11 functional did not show a very good agreement with the established order despite its good performance in the mean error. The obtained results support the use of similar validation strategies for proper prediction of BDE or other molecular properties by DF Tmethods in subsequent related studies.</p></div></div></div>

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Relativistic Effects on NMR Parameters of Halogen-Bonded Complexes

Molecules ◽

10.3390/molecules24234399 ◽

2019 ◽

Vol 24 (23) ◽

pp. 4399 ◽

Cited By ~ 4

Author(s):

Ibon Alkorta ◽

José Elguero ◽

Manuel Yáñez ◽

Otilia Mó ◽

M. Merced Montero-Campillo

Keyword(s):

Relativistic Effects ◽

Lewis Base ◽

Coupling Constants ◽

Basic Site ◽

Lewis Bases ◽

Nmr Parameters ◽

Quadrupolar Coupling ◽

Binary Complexes ◽

Computational Level ◽

Bonded Complexes

Relativistic effects are found to be important for the estimation of NMR parameters in halogen-bonded complexes, mainly when they involve the heavier elements, iodine and astatine. A detailed study of 60 binary complexes formed between dihalogen molecules (XY with X, Y = F, Cl, Br, I and At) and four Lewis bases (NH3, H2O, PH3 and SH2) was carried out at the MP2/aug-cc-pVTZ/aug-cc-pVTZ-PP computational level to show the extent of these effects. The NMR parameters (shielding and nuclear quadrupolar coupling constants) were computed using the relativistic Hamiltonian ZORA and compared to the values obtained with a non-relativistic Hamiltonian. The results show a mixture of the importance of the relativistic corrections as both the size of the halogen atom and the proximity of this atom to the basic site of the Lewis base increase.

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CAN SEMIEMPIRICAL QUANTUM MODELS CALCULATE THE BINDING ENERGY OF HYDROGEN BONDING FOR BIOLOGICAL SYSTEMS?

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633609005015 ◽

2009 ◽

Vol 08 (04) ◽

pp. 691-711 ◽

Cited By ~ 8

Author(s):

FENG FENG ◽

HUAN WANG ◽

WEI-HAI FANG ◽

JIAN-GUO YU

Keyword(s):

Hydrogen Bonding ◽

Amino Acid ◽

Amino Acid Residue ◽

Density Functional ◽

Biological Systems ◽

Binding Energies ◽

Semiempirical Model ◽

Hydrogen Bonded Systems ◽

High Level ◽

Hydrogen Bonded

A modified semiempirical model named RM1BH, which is based on RM1 parameterizations, is proposed to simulate varied biological hydrogen-bonded systems. The RM1BH is formulated by adding Gaussian functions to the core–core repulsion items in original RM1 formula to reproduce the binding energies of hydrogen bonding of experimental and high-level computational results. In the parameterizations of our new model, 35 base-pair dimers, 18 amino acid residue dimers, 14 dimers between a base and an amino acid residue, and 20 other multimers were included. The results performed with RM1BH were compared with experimental values and the benchmark density-functional (B3LYP/6-31G**/BSSE) and Möller–Plesset perturbation (MP2/6-31G**/BSSE) calculations on various biological hydrogen-bonded systems. It was demonstrated that RM1BH model outperforms the PM3 and RM1 models in the calculations of the binding energies of biological hydrogen-bonded systems by very close agreement with the values of both high-level calculations and experiments. These results provide insight into the ideas, methods, and views of semiempirical modifications to investigate the weak interactions of biological systems.

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5-Nitrosalicylic Acid and its Proton-Transfer Compounds with Aliphatic Lewis Bases

Australian Journal of Chemistry ◽

10.1071/ch04144 ◽

2005 ◽

Vol 58 (1) ◽

pp. 47 ◽

Cited By ~ 44

Author(s):

Graham Smith ◽

Andy W. Hartono ◽

Urs D. Wermuth ◽

Peter C. Healy ◽

Jonathan M. White ◽

...

Keyword(s):

Hydrogen Bonds ◽

Proton Transfer ◽

Lewis Base ◽

Unusual Structure ◽

Lewis Bases ◽

Carboxylate Oxygen ◽

Hydrogen Bonding Interactions ◽

Polymer Compound ◽

Proton Transfer Compounds ◽

Centrosymmetric Dimers

The crystal structures of the proton-transfer compounds of 5-nitrosalicylic acid (5-nsa) with morpholine (morph), hexamethylenetetramine (hmt), and ethylenediamine (en) have been determined and their solid-state packing structures described. The compounds are [(morph)+(5-nsa)–] 1, [(hmt)+(5-nsa)–·H2O] 2, and [(en)2+2(5-nsa)–·H2O] 3. In all compounds, protonation of the hetero-nitrogen of the Lewis base occurs. With 1, the 5-nsa anions and the morpholine cations lie, respectively, in or across crystallographic mirror planes and are linked within the planes by hydrogen-bonding interactions through the aminium group and the carboxylic and phenolic oxygens of the anionic 5-nsa species giving a two-dimensional sheet polymer. Compound 2 is an unusual structure with the planar 5-nsa anions lying within pseudo mirror planes and cyclically linked by duplex water bridges through a single carboxylate oxygen into centrosymmetric dimers. The hmt cation molecules are disordered across the pseudo mirror and are strongly linked by N+–H···O hydrogen bonds only to the water molecules with peripheral weak hmt C–H···O hydrogen bonds extending the dimer within and between the dimer planes. Compound 3 is a network polymer comprised of the 5-nsa anions, the en dianions, and the water molecule in an extensive hydrogen-bonded structure.

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Full Function Sampling of Uncertain Correlations

ASME 2020 Verification and Validation Symposium ◽

10.1115/vvs2020-8834 ◽

2020 ◽

Author(s):

Kevin W. Irick ◽

Jeff Engerer ◽

Blake Lance ◽

Scott A. Roberts ◽

Ben Schroeder

Keyword(s):

Mathematical Description ◽

Uncertain Data ◽

Input Stimulus ◽

Direct Sampling ◽

Data Correlations ◽

Input Range ◽

Correlation Space ◽

High Level ◽

Bounded Input ◽

The Relationship

Abstract Empirically-based correlations are commonly used in modeling and simulation but rarely have rigorous uncertainty quantification that captures the nature of the underlying data. In many applications, a mathematical description for a parameter response to some input stimulus is often either unknown, unable to be measured, or both. Likewise, the data used to observe a parameter response is often noisy, and correlations are derived to approximate the bulk response. Practitioners frequently treat the chosen correlation — sometimes referred to as the “surrogate” or “reduced-order” model of the response — as a constant mathematical description of the relationship between input and output. This assumption, as with any model, is incorrect to some degree, and the uncertainty in the correlation can potentially have significant impacts on system responses. Thus, proper treatment of correlation uncertainty is necessary. In this paper, a method is proposed for high-level abstract sampling of uncertain data correlations. Whereas uncertainty characterization is often assigned to scalar values for direct sampling, functional uncertainty is not always straightforward. A systematic approach for sampling univariable uncertain correlations was developed to perform more rigorous uncertainty analyses and more reliably sample the correlation space. This procedure implements pseudo-random sampling of a correlation with a bounded input range to maintain the correlation form, to respect variable uncertainty across the range, and to ensure function continuity with respect to the input variable.

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