| dc.contributor.author | Robertson, Katherine Nancy. | en_US |
| dc.date.accessioned | 2014-10-21T12:36:25Z | |
| dc.date.available | 2001 | |
| dc.date.issued | 2001 | en_US |
| dc.identifier.other | AAINQ66644 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55772 | |
| dc.description | High quality, low temperature, x-ray crystallographic data sets were collected for four organoammonium tetraphenylborates. On close scrutiny, two types of N-H...X interactions were identified, the more "traditional" N-H...N hydrogen bonds, and N-H...pi(Ph) hydrogen bonds [centroid, edge or single atom type], in which the phenyl ring of the anion serves as the hydrogen bond acceptor. In addition, the four salts were found to form a large number of close C-H...X type contacts. Some of these adopted hydrogen bond type geometries while others were classified as "H...H" type contacts, using criteria developed in this work. | en_US |
| dc.description | Charge density calculations were carried out on the four salts. From the results, static and dynamic electron density maps were plotted in a variety of planes to see if evidence of the intermolecular interactions would be visible. The conventional N-H...N hydrogen bonds were used as the internal standard with which the other, weaker, interactions could be compared. Certain features were identified in the maps that could consistently be attributed to the formation of N-H...pi(Ph) hydrogen bonds. | en_US |
| dc.description | The electron density distributions calculated using the aspherical models generated in the XD refinements were used as input for topological analyses of the four salts. This allowed a more quantitative investigation of the weak intermolecular interactions. The location of a rational bond path and a (3, -1) bond critical point was characteristic of almost every contact studied. The values, at the bond critical points, of the electron density, rhob (r), and the Laplacian of the electron density, ∇ 2rhob(r), were calculated. They were always positive, typical of closed shell interactions, and were shown to be correlated with the distance over which the interaction occurred, specified in this work as the H...acceptor distance. In both cases [rhob( r)/∇2rhob(r) versus d(H...A)], a simple exponential curve was found to model the collected experimental data reasonably well. The experimentally derived topological data from this work were consistent with literature values reported for more traditional hydrogen bonds, which shows the N-H...pi(Ph) hydrogen bonds behave topologically like all others. Finally, the majority of the C-H...phenyl interactions were identified as "H...H" type contacts, while the remainder were found to be hydrogen bonds, behaving topologically like other X-H...pi(Ph) hydrogen bonds. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 2001. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Chemistry, Organic. | en_US |
| dc.subject | Chemistry, Physical. | en_US |
| dc.title | Intermolecular interactions in a series of organoammonium tetraphenylborates. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
