Our work highlights DHB@MNP-induced pseudo-MS/MS for oligosaccharide characterization, with some insights on this nanoparticle-mediated energy transfer dynamics.
The potential energy surfaces for the ring expansion reactions of 16-valence-electron d10 metallacyclopropane species have been studied using density functional theory (B3LYP/LANL2DZ). Three metallacyclopropane species of the form (η2-TCNE)M(η-CNC6H5)2, where M = Ni, Pd, and Pt, have been chosen as model reactants in this work. Also, the isocyanide with the form CNC6H5 has been used to study the ring expansion reactivities of these group 10 transition metal elements. Accordingly, this ring expansion reaction can be considered to proceed from metallacyclopropane to metallacyclopentane via the insertions of two isocyanide molecules. The present theoretical investigations suggest that the relative 16-valence-electron metallacyclopropane species’ reactivity increases in the order nickelacyclopropane (1) < palladcyclopropane (2) ≪ platinacyclopropane (3). That is, a less electronegative as well as a heavier group 10 atom center will lead to a smaller ΔE
st and, in turn, will facilitate the ring expansion reactions with isocyanides. Furthermore, the singlet−triplet energy splitting of the 16 valence-electron metallacyclopropane species, as described in the configuration mixing model attributed to the work of Pross and Shaik, can be used as a diagnostic tool to predict their ring expansion reactivities. The results obtained allow a number of predictions to be made.
DFT studies on several dppf- and dppc-derived bidentate phosphines ligated palladium complexes catalyzed Suzuki-Miyaura coupling reactions were pursued. The catalytic reactions employing ligands, having two phosphine biting sites on different cyclpentadienyl or cyclobutadiene rings, such as 1,1'-dmpf or 1,1'-dmpc, have been verified to be energetically more favorable than those on the same ring provided that tetra-coordinated palladium conformations for all transition states and intermediates are maintained. Apart from the purpose of storage, the application of phosphinous acid (R2P(OH)) in Suzuki-Miyaura reaction is inferior to tertiary phosphine (R3P)
The potential energy surfaces for the abstraction reactions of heavy cyclobutenes with CCl(4) have been characterized in detail by using density functional theory (B3LYP/LANL2DZdp), including zero-point corrections. Seven heavy cyclobutene species including A (C-C-C=C), B (Si-Si-Si=Si), C (Ge-Ge-Ge=Ge), D (Si-Si-Ge=Ge), E (Si-Si-Ge=Sn), F (Sn-Sn-Sn=Sn), and G (Pb-Pb-Pb=Pb) have been chosen in this work as model reactants. All the interactions involve a Cl or CCl(3) shift via a two-center transition state. The activation barriers and enthalpies of the reactions were compared in order to determine the relative heavy cyclobutene reactivity as well as the influence of substituents on the reaction potential energy surface. As a result, our theoretical investigations suggest that a heavy cyclobutene species that contains more massive and less electronegative atoms in the double bond should undergo radical abstraction reactions with CCl(4) more readily than one containing less massive and more electronegative atoms. Moreover, we show that having undergone an initial chlorine atom abstraction, a heavy cyclobutene will then proceed to undergo a second abstraction to give a tetrachloro derivative. Furthermore, a configuration mixing model based on the work of Pross and Shaik is used to rationalize the computational results. The results obtained allow us to make several predictions.
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