dc.contributor.author | Luo, Yu-Ran. | en_US |
dc.date.accessioned | 2014-10-21T12:35:41Z | |
dc.date.available | 1991 | |
dc.date.issued | 1991 | en_US |
dc.identifier.other | AAINN71423 | en_US |
dc.identifier.uri | http://hdl.handle.net/10222/55248 | |
dc.description | New, simple and empirical methods have been proposed for estimating the homolytic and heterolytic dissociation energies of alkyl-X bonds, where X represents a halogen or hydrogen atom and CH$\sb3$, SiH$\sb3$, GeH$\sb3$, NH$\sb2$, PH$\sb2$, OH, SH, and C- or Si-centered groups. The uncertainties for most values estimated by these methods are within the accuracy of experimental determination ($\pm$1 kcal/mol). New and simple algorithms for estimating ionization potentials or alkyl radicals, hydrocarbons, and chloro-, bromo- and iodoalkanes have been established. | en_US |
dc.description | A new, step-by-step approach is used to attack these problems. In the first step, Pauling's semi-quantitative electronegativity (EN) scale has been replaced by the covalent potential, V$\sb{\rm x}$ = $\sb{\rm x} / \rm r\sb{\rm x}$, where n$\sb{\rm x}$ is the number of valence electrons in the bonding atom in X, and r$\sb{\rm x}$ is the covalent radius of the bonding atom. From this and the many accurate experimental results available in the literature, the rules for calculating homolytic and heterolytic dissociation energies can be devised. | en_US |
dc.description | The new procedure correlates quantitatively with the four factors which determine the dissociation energies of alkyl-X and alkylsilyl-X bonds and energetics of species. The four factors are: (1) the new scale of EN or the covalent potential of X, V$\sb{\rm x}$; (2) the degree of methyl substitution on the alkyl radical center or the formal charge center, m; (3) the interactions between the radical center or formal charge center and the distant atoms, "the $\gamma$ effect"; and (4) the steric compression relief due to bond cleavage. The "constancy" of the bond energies of Si-H, Si-C and Si-Si bonds is explained using these factors. | en_US |
dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1991. | en_US |
dc.language | eng | en_US |
dc.publisher | Dalhousie University | en_US |
dc.publisher | | en_US |
dc.subject | Chemistry, Physical. | en_US |
dc.title | Homolytic and heterolytic energies of alkyl-X bonds and ionization potentials of alkyl radicals, alkanes and haloalkanes. | en_US |
dc.type | text | en_US |
dc.contributor.degree | Ph.D. | en_US |