The basic borazine molecule has a planar hexagonal structure of six alternating boron nitrogen atoms that was initially used as fuel additives and rocket fuels, but more recently, its polymeric material is used in semi conductive boron nitride (BN) ceramics. However, borazines containing organic fragment are less well-known. The development of a facile method for the synthesis of the borazine derived from 2-aminophenol with suitable boron reagents is of interest in our group to study the physical and chemical properties of these novel compounds. Initially, we proceeded by mixing sodium borohydride and 2-aminophenol in dry THF under N2 atmosphere, and BF3-OEt2 was slowly added via syringe. The reaction mixture was heated to reflux for 3 h and washed with hot dioxane. The crude product, isolated by filtration under a nitrogen atmosphere and dried under vacuum, was obtained as a light brown solid in a 93% yield. The product was analyzed by IR, and 1H and 11B NMR. The characteristic signal for the borazine ring appeared at ~20.0 ppm in the 11B NMR. The decomposition point was 215 °C, like the reported melting point of the desired borazine. We plan to continue exploring the best purification conditions to obtain this borazine in a pure form to study its physical properties for future applications in electronic devices. The second method proceeded by the slow addition of a solution of 2-aminophenol in dry THF to a solution of BH3-DMS in dry THF at 0 °C, and then the solution was left stirring for 3 h at the same temperature. The formed white solid was slowly heated at 170 °C in an oil bath, and then the mixture was left heating one hour at 170 °C. The product was analyzed by IR and 11B NMR. The characteristic signal for the borazine ring appeared at ~19.0 ppm in the 11B NMR, indicating that the borazine was obtained. Further studies are in progress to investigate electronic properties of these borazines.

Synthesis of the organic borazine derived from 2-aminophenol using sodium borohydride and boron trifluoride-etherate

254th National Meeting (2017)

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