In an attempt to ascertain the relationship between the structure and the electronic spin ground state of open-shell species, various model $\pi$-conjugated dinitrene systems of the general structure:N-Ph-X-Ph-N: were synthesized. Variable low temperature electron spin resonance (ESR) spectroscopy was used to determine the ground state multiplicity of the dinitrenes and to determine the degree of exchange coupling between the unpaired electrons on each nitrogen. The experimentally determined ground state spin multiplicity could be predicted using Borden and Davidson's disjointness criterion, even for heterocyclic non-alternant ring systems. Parity-based predictions did not provide such consistent agreement with the experimental results as the latter method. Many similarities between the ESR spectra of the quintet dinitrenes are proposed to arise from different conformers of the same quintet state. Analysis of two conformationally restrained dinitrenes tend to support this view, and imply that geometric considerations are of importance in the design of an organic ferromagnet.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-9000 |
| Date | 01 January 1994 |
| Creators | Ling, Christopher |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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