A new synthetic route to silylhydrazine molecules and polymers has been developed by the heterodehydrocoupling of organosilanes with hydrazines. A dimethyltitanocene catalyst has been employed to facilitate the dehydrocoupling reaction. The dehydrocoupling was shown to proceed by stepwise replacement of Si-H with hydrazino groups. The controlled hydrolysis of Ph$ sb2$Si(NHNHMe)$ sb2$ formed a hydrazinodisiloxane. Cyclizations of Ph$ sb2$Si(NHNHMe)$ sb2$ to form cyclic silylhydrazines were achieved by the reaction with n-BuLi/Ph$ sb2$SiCl$ sb2,$ or MeI (or HCl or Ph$ sb2$SiCl$ sb2),$ or thermolysis. Crystal structures of Ph$ sb2$Si(NHNR)(NRNH)SiPh$ sb2$ (R = H, Me) reveal chair (R = H) and twist-boat (R = Me) conformations of the Si$ sb2$N$ sb4$ ring, respectively. Planar and pyramidal nitrogen geometries were found to coexist in a hydrazino unit. A preceramic polymer, synthesized by the polymerization of MeHSiCl$ sb2$ with hydrazine in an appropriate ratio, was pyrolyzed to Si$ sb3$N$ sb4$/SiC$ rm sb{x}$N$ rm sb{y}$ in 67-80% ceramic yields. It is proposed that the structural unit of this polymer is a tetraazadisilacyclohexane bridged by MeHSi groups. This assignment is based on $ sp{1}$H and $ sp{29}$Si NMR measurements, as well as by comparison with the well-defined reaction product of Me$ sb2$Si(NHNH) $ sb2$SiMe$ sb2$ with MeHSiCl$ sb2.$ The pyrolysis was carried out from room temperature to 1500$ sp circ$C under argon and studied by using thermogravimetric analysis, solid-state $ sp{29}$Si NMR spectroscopy, infrared spectroscopy, x-ray powder diffraction, and elemental analysis. Serial structural changes were characterized in the pyrolyzed solid products. The ceramic product of this polymer at 1100$ sp circ$C was found to possess a quasi-metallic electrical conductivity ($ sigma$ = 10$ sp3$ ($ Omega$cm)$ sp{{-}1}),$ and was evaluated as an electrode material.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.29044 |
| Date | January 1995 |
| Creators | He, Jiliang |
| Contributors | Harrod, John F. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001476610, proquestno: NN08112, Theses scanned by UMI/ProQuest. |
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