GenLocDip: A Generalized Program to Calculate and Visualize Local Electric Dipole Moments

Deciphering Stereoselectivity in Hurd-Claisen Rearrangements: A Comprehensive Study of Electrostatic Interactions from Shubin's Energy Decomposition Analysis

In this study, we explore the stereoselectivity of Hurd-Claisen Rearrangements, focusing on the influence of two electron-withdrawing groups and eight diverse substituents. Utilizing the Curtin-Hammett principle, we performed energy calculations for reactions, products, and transition states using the M062X/def2TZVPP compound model. Our analysis reveals that kinetic factors predominantly dictate the reaction equilibrium. A key aspect of our research is the application of Shubin's energy decomposition analysis to optimized transition states, highlighting the significant role of electrostatic interactions in determining stereoselectivity. We further dissected each transition state into four fragments: the electron-withdrawing groups (C O 2 E t ${CO_2 Et}$ ,C N ${CN}$ ), the Hurd group ( H ${H}$ ), various substituents (C H 3 ${CH_3 }$ ,E t ${Et}$ ,S P r o p ${SProp}$ ,T B u t ${TBut}$ ,I s o B u t ${IsoBut}$ ,N H 2 P h ${NH_2 Ph}$ ,N O 2 P h ${NO_2 Ph}$ ,P h ${Ph}$ ), and the central fragment. This fragmentation approach enabled an in-depth analysis of group dipole moments, providing insights into the electrostatic forces at play. Our findings shed light on the intricate mechanisms driving stereoselectivity in Hurd-Claisen Rearrangements and enhance the understanding of molecular interactions, offering valuable implications for organic synthesis.

Unprecedented E-stereoselectivity on the sigmatropic Hurd-Claisen rearrangement of Morita-Baylis-Hillman adducts: a joint experimental-theoretical study

Herein we report the first systematic investigation of the tandem mercury(ii) catalysed transvinylation/Hurd-Claisen rearrangement of MBH adducts derived from alkyl acrylates. This is the first report of E-selectivity for MBH adducts with alkyl side chains and is complementary to the previously reported Johnson-Claisen and Eschenmoser-Claisen rearrangements. The rearrangement products were obtained in good yields and could be readily converted to 2-alkenyl δ-valerolactones. Combined DFT and F-SAPT studies demonstrate that reaction rates are primarily governed by non-covalent interactions dictating the relative stability of the transition states. Our F-SAPT calculations revealed that the hyperconjugative effects are not so significant, but that electrostatic interactions, instead, are the driving forces for the relative E : Z stereoselectivity.

Visual Chemical Detection Mechanism by a Liquid Gating System with Dipole-Induced Interfacial Molecular Reconfiguration

Chemical detection has a wide range of applications. The detection of a certain substance is so vital that new detection mechanisms with features such as low-cost, accessibility, and readily available visual markers are in demand. Herein, a liquid-gating-based chemical-detection mechanism is reported, which has a dynamic gas/liquid interface due to dipole-induced interfacial molecular reconfiguration. The mechanism exhibits a sensitive relationship between the dipole-force-induced rearrangement of interfacial molecules and transmembrane gating behavior. These features can be utilized to create visual markers for detection by converting the analyte-mediated interfacial interaction to a pressure-driven marker movement. This "green" detection mechanism requires no electrical energy input and has readily available markers for anyone to observe directly. This new mechanism opens a window for a more in-depth exploration of combining liquid-gating mechanisms with detection mechanisms.

Modeling adsorbate-induced property changes of carbon nanotubes

Because of their potential for chemical functionalization, carbon nanotubes (CNTs) are promising candidates for the development of devices such as nanoscale sensors or transistors with novel gating mechanisms. However, the mechanisms underlying the property changes due to functionalization of CNTs still remain subject to debate. Our goal is to reliably model one possible mechanism for such chemical gating: adsorption directly on the nanotubes. Within a Kohn-Sham density functional theory framework, such systems would ideally be described using periodic boundary conditions. Truncating the tube and saturating the edges in practice often offers a broader selection of approximate exchange-correlation functionals and analysis methods. By comparing the two approaches systematically for NH₃ and NO₂ adsorbates on semiconducting and metallic CNTs, we find that while structural properties are less sensitive to the details of the model, local properties of the adsorbate may be as sensitive to truncation as they are to the choice of exchange-correlation functional, and are similarly challenging to compute as adsorption energies. This suggests that these adsorbate effects are nonlocal. © 2017 Wiley Periodicals, Inc.