Structural Trends in Silicon Atranes

Ab initio calculations with full geometry optimization are performed on a wide range of silicon atranes, RSi[-Y(CH2)z-]3N, where R = H, F, OH, NH2, CH3, Cl, SH, PH2, SiH3, andY= 0, NH, NCH3, CH2. using the 6-31G(d) or larger basis sets. The results are used to show trends in the dative SiN bond as a function of axial R and equatorial Y substitution. The SiN bond is shown to be quite weak, making the atrane geometries very sensitive to medium effects, as shown by model solvation computations. The nature of the SiN bonding is best described as dative, as shown by localized orbitals

Applications of Parallel GAMESS

In this paper we discuss several recent applications that would have been difficult or impossible without the availability of the parallel implementation of the electronic structure code GAMESS. These applications include the study of highly strained rings, such as inorganic prismanes and bicyclobutanes, cage compounds such as cyclophanes and atranes, the neutral \u3c-\u3e zwitterion isomerization of glycine, transition metal-main group binding, and the implementation of parallel graphics

NEGATIVE ION PHOTOELECTRON SPECTROSCOPY: ELECTRONIC STRUCTURES, CHEMICAL BONDING, MOLECULAR ACTIVATION, AND ELECTRON-MOLECULE INTERACTIONS

Negative ion photoelectron spectroscopy has been applied to address a broad range of fundamental problems in chemistry. Major topics that have been studied are related to electronic structures, chemical bonding, molecular activation, and electron-molecule interactions. New phenomena have been discovered, including but not limited to, the fine-tunability of the electronic spectra in superatoms, realization of Lewis basic sodium anion, halogen-bond stabilized anions, selective methane activation by single atomic anions, and excess electrons tethered by weak attractive interactions. The insight acquired from negative ion photoelectron spectroscopy has provided understanding into the above-mentioned topics at a molecular level

Acyclic stereocontrol and chemical diversity & application to the total synthesis of Bafilomycin A₁

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal