A synthetic methodology is developed to generate boron rich aromatic small molecules based on benzene and pyrene moieties for the detection of thermal neutrons. The prepared aromatic compounds have a relatively high boron content up to 7.4 wt%, which is important for application in neutron detection as 10B (20% of natural abundance boron) has a large neutron induced reaction cross-section. This is demonstrated by preparing blends of the synthesized molecules with fluorescent dopants in poly(vinyltoluene) matrices resulting in comparable scintillation light output and neutron capture as state-of-the art commercial scintillators, but with the advantage of much lower cost. The boron-rich benzene and pyrene derivatives are prepared by Suzuki conditions using both microwave and traditional heating, affording yields of 40-93%. This new procedure is simple and straightforward, and has the potential to be scaled up.
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This research is supported by the US Department of Homeland Security-Domestic Nuclear Office (DHS-14-DN-077-ARI-NC7).
Yemam, Henok A.; Mahl, Adam; Koldemir, Unsal; Remedes, Tyler; Parkin, Sean; Greife, Uwe; and Sellinger, Alan, "Boron-Rich Benzene and Pyrene Derivatives for the Detection of Thermal Neutrons" (2015). Chemistry Faculty Publications. 49.
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Figure 1: Conventional heating condition (Trad.) and Microwave (μW) heating condition for generating tetra-borylated pyrene (TBP).
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Figure 2: Boron containing pyrene and benzene derivatives.
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Figure 3: MALDI-TOF-MS of TBP with 1,8,9-trihydroxyanthracene as a matrix.
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Figure 4: An ellipsoid plot (50% probability) for TBP.
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Figure 5: Left to right: Sample v and vi incorporating 1 and 5% 124TrBB respectively.
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Figure 6: Thermal neutron capture using a 5% 124TrBB plastic scintillator, sample vi.
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Figure 7: Left to right: Sample ix, x and xi incorporating 1, 2 and 1% TBP respectively.