Ecological and evolutionary responses to landscape structure

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Selected Synthetic Studies of NLO pi-Bridges and Thermally Stable Monomers

The molecular weights of two series of PEEK polymers were determined using gel permeation chromatography (GPC). The first series contains oxyalkylene linkages. The other series contains oxyethylene linkages. The synthesis of several thermally stable monomers has been investigated. These monomers include 9,9-dihexylfluorene-2,7-dicarboxaldehyde, 2,7-bis(bromomethyl)-9,9- dibutylfluorene and 2,7-bis(hydroxymethyl)-9,9-diethylfluorene. These monomers can be used to form polymers that will contain short conjugated segments separated by nonconjugated segments. The synthesis of 50 g of each of the following monomers was accomplished: bis(3-methylphenyl) phenylphosphine oxide, bis(4-methylphenyl)phenylphosphine oxide, bis(3- carboxyphenyl)phenylphosphine oxide and bis(4-carboxyphenyl)phenylphosphine oxide. These monomers will be used in a polymerization to form polybenzoxazoles. The synthesis of the NLO pi-bridge 2,10-dibromo-5,6-diphenyl-11,12- dihydroindeno[2.1-a] was accomplished. Alkylation of this compound was attempted, but the results were inconclusive. This project was abandoned due to the consistently low yields. Another NLO pi-bridge that was attempted contained the c-fused system, however, the initial steps also showed consistently low yields. Because of low yields, this project was also abandoned