Study of additions of disilanes to acetylenes and their applications in organic and polymer synthesis

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1998
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Ma, Zhongxin
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Tom J. Barton
Mark S. Gordon
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Chemistry

The Department of Chemistry seeks to provide students with a foundation in the fundamentals and application of chemical theories and processes of the lab. Thus prepared they me pursue careers as teachers, industry supervisors, or research chemists in a variety of domains (governmental, academic, etc).

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The Department of Chemistry was founded in 1880.

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Three separate studies are included in this dissertation;The first section of this thesis addresses the discovery of the trans-addition of disilanes to acetylenes. The reaction was performed with the 5,5,6,6-tetramethyl-3,3,8,8-tetraphenyl-4,7-dioxa-5,6-disila-cyclooctayne (1) under argon flow at 600°C to give 1,1,4,4-tetramethyl-3,3,6, 6-tetraphenyl-2,5-dioxa-1,4-disila-dicyclo (3,3,0) octa-7-ene (2). Ab initio calculations with MP4/6-31G** were carried out to find the transition state structure. The activation energy was determined to be 34 kcal/mol. It was found that the intramolecular trans-addition of disilane to acetylene also occurred photochemically when the acetylene is conjugated with an aromatic group;The second section of this thesis involves the synthesis of a novel, blue light-emitting molecules containing the 3,3,3',3'-tetramethyl-3,3 '-disila-indeno (2,1-a) indene unit were synthesized with our recently discovered intramolecular addition of disilanes to acetylenes. Light-emitting diodes (LEDs) were fabricated by vapor deposition. The chromophore was also incorporated into polysiloxanes and polymethacrylate as pendent groups. Due to their high chemical stabilies and quantum yields, these polymers are excellent candidates for fabrication of polymer-based blue-light LEDs;The last section deals with the synthesis of a 2-silaoxetane molecule by the catalytic intramolecular addition of disilane to acetylene. The stability of the molecule was studied thermochemically and photochemically. The activation energy of decomposition of the 2-silaoxetane was found to be about 49.24 kcal/mol and Log(A) was 15.37. This process was also studied by ab initio calculations which showed that the decomposition was a highly non-synchronized but concerned process. The four-membered ring system expanded to a five-membered ring photochemically.

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Thu Jan 01 00:00:00 UTC 1998