Long but Strong C−C Single Bonds: Challenges for Theory

The Chemical Record, Journal Year: 2023, Volume and Issue: 24(2)

Published: June 26, 2023

Abstract Theoretical challenges in describing molecules with anomalously long single C−C bonds are analyzed terms of the relative contributions stabilizing and destabilizing intramolecular interactions. Diamondoid dimers that stable despite presence up to 1.7 Å long, as well other bulky stabilized due noncovalent interactions (London dispersions) discussed. The unexpected stability highly crowded molecules, such diamondoid tert‐ butyl‐substituted hexaphenylethanes, calls for reconsideration “steric effect” traditionally thought destabilize molecule. Alternatively, attraction” helps understand bonding sterically overloaded whose structural energetic analysis requires a proper theoretical description

Language: Английский

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Comparison of N···I and N···O Halogen Bonds in Organoiodine Cocrystals of Heterocyclic Aromatic Diazine Mono-N-oxides

Crystal Growth & Design, Journal Year: 2024, Volume and Issue: 24(6), P. 2425 - 2438

Published: March 5, 2024

A series of cocrystals halogen bond donors 1,4-diiodotetrafluorobenzene (p-F4DIB) and tetraiodoethylene (TIE) with five aromatic heterocyclic diazine mono-N-oxides based on pyrazine, tetramethylpyrazine, quinoxaline, phenazine, pyrimidine as bonding acceptors were studied. Structural analysis the allows comparison competitive occurrence N···I vs O···I interactions relative strength directionality these two types interactions. Of mono-N-oxide organoiodine examined, six exhibited 1:1 stoichiometry, forming chains that utilized both Two presented stoichiometry exclusive displayed a 2:1 stoichiometry─one characterized solely by other We have also compared to those present in corresponding diazines, some which we report here been previously reported. In addition, computational using density functional theory (M062X/def2-SVPD) was performed systems has experimental results. The calculated complex formation energies were, average, 4.7 kJ/mol lower for I···O interaction interaction. average distances be 0.15 Å shorter than I···N

Language: Английский

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The Cambridge Structural Database and structural dynamics

Structural Dynamics, Journal Year: 2024, Volume and Issue: 11(2)

Published: March 1, 2024

With the availability of computer readable information in Cambridge Structural Database (CSD), wide ranging, largely automated comparisons fragment, molecular, and crystal structures have become possible. They show that distributions interatomic distances, angles, torsion angles for a given structural fragment occurring different environments are highly correlated among themselves with other observables such as spectroscopic signals, reaction activation energies. The correlations often extend continuously over large ranges parameter values. reminiscent bond breaking forming reactions, polyhedral rearrangements, conformational changes. map-qualitatively-the regions space which molecular dynamics take place, namely, low energy respective (free) surfaces. extension continuous nature provides an organizing principle groups data suggests reconsideration traditional definitions descriptions bonds, "nonbonded" "noncovalent" interactions terms Lewis acids interacting bases. These aspects illustrated selected examples historic importance some later developments. It seems amount CSD (and databases) knowledge on of, within, this body should allow one-in near future-to make credible interpolations possibly predictions their properties machine learning methods.

Language: Английский

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Computational and Spectroscopic Studies on the Formation of Halogen‐Bonded Complexes Between Tertiary Amines and CBr4 and Application in the Light‐mediated Amino Acid Coupling

ChemPlusChem, Journal Year: 2024, Volume and Issue: unknown

Published: May 7, 2024

In recent years, halogen-bonded complexes (XBCs), in solution, have played a pivotal role inducing photochemical organic reactions. this work, we explore the ability of various tertiary amines to act as XB acceptors presence donor CBr

Language: Английский

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Affinity of Telluronium Chalcogen Bond Donors for Lewis Bases in Solution: A Critical Experimental‐Theoretical Joint Study

Chemistry - A European Journal, Journal Year: 2023, Volume and Issue: 30(7)

Published: Nov. 16, 2023

Telluronium salts [Ar

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Multiple hydrogen-bonded dimers: are only the frontier atoms relevant?

Physical Chemistry Chemical Physics, Journal Year: 2023, Volume and Issue: 26(15), P. 11306 - 11310

Published: Nov. 30, 2023

Non-frontier atom exchanges in hydrogen-bonded aromatic dimers can induce significant interaction energy changes (up to 6.5 kcal mol

Language: Английский

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Decoding energy decomposition analysis: Machine‐learned Insights on the impact of the density functional on the bonding analysis

Journal of Computational Chemistry, Journal Year: 2023, Volume and Issue: 45(7), P. 368 - 376

Published: Nov. 1, 2023

Abstract The concept of chemical bonding is a crucial aspect chemistry that aids in understanding the complexity and reactivity molecules materials. However, interpretation bonds can be hindered by choice theoretical approach specific method utilized. This study aims to investigate effect choosing different density functionals on achieved through energy decomposition analysis (EDA). To achieve this goal, data set was created, representing four groups various combinations dispersion correction schemes. calculations showed significant variation among for EDA terms, with terms exhibiting highest variability. More information extracted using machine learning combination dimensionality reduction set. Results indicate that, despite differences obtained from functionals, functional has least impact, suggesting minimal influence interpretation.

Language: Английский

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A Deeper Insight into the Supramolecular Activation of Oxidative Addition Reactions Involving Pincer‐Rhodium(I) Complexes

ChemPhysChem, Journal Year: 2024, Volume and Issue: 25(7)

Published: Jan. 25, 2024

Abstract The factors governing the acceleration of oxidative addition methyl iodide to pincer rhodium(I)‐complexes induced by coronene have been computationally explored in detail using quantum chemical methods. Both parent reaction and coronene‐mediated process proceed via a stepwise S N 2‐type mechanism. It is found that derives from formation an initial supramolecular complex, mainly stabilized electrostatic π‐π interactions, which significantly increases electron richness complex. impact this effect on barrier has quantitatively analyzed applying activation strain model combination with energy decomposition analysis method. In addition, influence other polycyclic aromatic hydrocarbons also considered.

Language: Английский

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Crystal Clear: Decoding Isocyanide Intermolecular Interactions through Crystallography

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(2), P. 957 - 974

Published: Jan. 4, 2024

The isocyanide group is the chameleon among functional groups in organic chemistry. Unlike other multiatom groups, where electrophilic and nucleophilic moieties are typically separated, isocyanides combine both functionalities terminal carbon. This unique feature can be rationalized using frontier orbital concept has significant implications for its intermolecular interactions reactivity of group. In this study, we perform a Cambridge Crystallographic Database-supported analysis intramolecular to investigate solid state, excluding isocyanide–metal complexes. We discuss examples different interaction classes, including as hydrogen bond acceptor (RNC···HX), halogen bonding (RNC···X), involving carbon atoms (RNC···C). latter serves an intriguing illustration Bürgi–Dunitz trajectory represents crucial experimental detail well-known multicomponent reactions such Ugi- Passerini-type mechanisms. Understanding spectrum that undergo holds fields medicinal chemistry, materials science, asymmetric catalysis.

Language: Английский

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Assessing the Possibility and Properties of Types I and II Chalcogen Bonds

Crystals, Journal Year: 2023, Volume and Issue: 13(5), P. 766 - 766

Published: May 4, 2023

Type I and II halogen bonds are well-recognized motifs that commonly occur within crystals. Quantum calculations applied to examine whether such geometries might in their closely related chalcogen bond cousins. Homodimers constructed of the R1R2C=Y R1R2Y monomers, wherein Y represents a atom, S, Se, or Te; R1 R2 refer either H F. A (T2) geometry lone pair one is aligned with σ-hole its partner stable arrangement for all except YH2, although not structures true minima. The symmetric T1 which each atom serves as both electron donor acceptor slightly higher energy R1R2C=Y, but reverse R1R2Y. Due deeper σ-holes, latter molecules engage stronger than do former, exception H2Y, whose dimers barely bound. interaction energies rise grows larger: S < Se Te.

Language: Английский

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