Dynamic Effects in Intramolecular Schmidt Reactions: Entropy, Electrostatic Drag, and Selectivity Prediction

Electrostatic drag in the intramolecular Schmidt reactions of azidopropylcyclohexanones is characterized using density functional theory (DFT) calculations and direct dynamics simulations. Despite resulting from enthalpically favorable interactions, electrostatic drag slows down N₂ loss during formation of bridged lactam products, an effect with implications for controlling product selectivity.

Alkali metal mediated C-C bond coupling reaction

Metal catalyzed carbon-carbon (C-C) bond formation is one of the important reactions in pharmacy and in organic chemistry. In the present study, the electron and hole capture dynamics of a lithium-benzene sandwich complex, expressed by Li(Bz)2, have been investigated by means of direct ab-initio molecular dynamics method. Following the electron capture of Li(Bz)2, the structure of [Li(Bz)2](-) was drastically changed: Bz-Bz parallel form was rapidly fluctuated as a function of time, and a new C-C single bond was formed in the C1-C1' position of Bz-Bz interaction system. In the hole capture, the intermolecular vibration between Bz-Bz rings was only enhanced. The mechanism of C-C bond formation in the electron capture was discussed on the basis of theoretical results.

Photoelectron imaging and theoretical study on nascent hydrogen bond network in microsolvated clusters of Au- (CH3OH)n (n = 1-5)

We first demonstrate the photoelectron spectroscopic evidence of the transition of two competitive solvation patterns in the Au(-)(CH3OH)n (n = 1-5) clusters. Quantum chemical calculations have been carried out to characterize the geometric structures, energy properties and hydrogen-bonded patterns, and to aid the spectral assignment. It has been found that the nonconventional hydrogen bonds dominate the small clusters (n = 1 and 2), whereas the conventional hydrogen bonds play more and more important role from n = 2 to n = 5. This finding provides concrete hydrogen bond network evolution of Au(-) surrounded by methanol molecules.

Photoelectron velocity-map imaging spectroscopic and theoretical study on the reactivity of the gold atom toward CH3SH, CH3OH, and H2O

Photoelectron velocity-map imaging spectroscopy has been used to study the reaction of the anionic gold atom with the HR (R = SCH3, OCH3, OH) molecules. The solvated [Au···HR](-) and inserted [HAuR](-) products have been experimentally observed for R = SCH3, whereas only solvated [Au⋯HR](-) products were found for R = OCH3 and OH. This significant difference in the photoelectron spectra suggests the different reactivity of the Au(-) toward the CH3SH, CH3OH, and H2O molecules. Second order Møller-Plesset perturbation theory and coupled-cluster single double triple excitation calculations have been performed to aid the structural assignment of the spectra and to explore the reaction mechanism. Activation energies for the isomerizations of the solvated structures to the inserted ones in the Au(-)∕Au + HR reactions (R = OCH3 and OH) are predicted to be much higher than those for the Au(-)∕Au + CH3SH reactions, supporting the experimental observation. Theoretical calculations provide the evidence that the intriguing [HAuSCH3](-) product may be formed by the attachment of the electron onto the neutral HAuSCH3 species or the isomerization from the anionic [Au···HSCH3](-) one. These findings should be helpful for understanding the feature that the thiols are able to form the staple motifs, whereas CH3OH and H2O are not.