Development of polymerizable 2-(1-naphthyl)-5-phenyloxazole scintillators for ionizing radiation detection

Abstract

The synthesis, chemical characterization and optical properties of 2-(1-naphthyl)-4-vinyl-5phenyloxazole (vNPO) and 2-(1-naphthyl)-4-allyl-5-phenyloxazole (allylNPO) monomers are reported.Starting with the organic fluor 2-(1-naphthyl)-5-phenyloxazole (aNPO), the vNPO and allylNPO monomers were synthesized using Stille coupling followed by purification. The final products were obtained with yields of B95% and B55% for vNPO and allylNPO. The absorption/emission spectra of aNPO, vNPO and allylNPO revealed that vNPO has the largest red-shifted in emission with an average wavelength of B420 nm, which is an advantage for increasing photomultiplier tube sensitivity without the need to add a wavelength shifter. Stable scintillating resin beads were prepared through copolymerization of the newly synthesized fluor monomers with styrene or 4-methylstyrene and divinylbenzene in the presence of toluene porogen. The resin beads were chemically stable and retained the ability to scintillate efficiently after energy deposition of beta particles from 99 Tc. This result indicates efficient energy transfer occurs from the base polymer to the covalently attached fluors with subsequent fluorescence in the presence of ionizing radiation. † Electronic supplementary information (ESI) available: Listing of chemical analysis, scintillation measurement setup, 13 C spectra, GCMS chromatograms, optical image for the plastic beads and absorption/emission spectra. See Scheme 1 Synthesis of monomer 2-(1-naphthyl)-4-vinyl-5-phenyloxazole (vNPO) and 2-(1-naphthyl)-4-allyl-5-phenyloxazole (allylNPO).

Hybrid Nanoparticle–Polymer Brush Composites for Detection of Low‐Level Radiostrontium in Water

“…The monomers mixture contained 1 or 3 wt% of a fluorophore monomer vNPO or vPZ1, which can be copolymerized with 4‐methylstyrene. Details of the vinyl modified fluorophores syntheses are discussed elsewhere . ARGET‐ATRP was carried out inside the glovebox at 65 °C for 24–48 h in a sand bath with stirring at 250 rpm.…”

“…Details of the vinyl modified fluorophores syntheses are discussed elsewhere. [27,28] ARGET-ATRP was carried out inside the glovebox at 65 °C for 24-48 h in a sand bath with stirring at 250 rpm. After polymerization, the reaction mixture was cooled to room temperature and modified SL (or HNT) particles were thoroughly washed with THF and dried in vacuum.…”

New Efficient Organic Scintillators Derived from Pyrazoline

“…The organic syntheses of 5-(4-bromophenyl)-3-(4-ethylphenyl)-1-phenyl-4,5-dihydro-1 H -pyrazole (PZ1) and 3-(4-ethylphenyl)-5-(4-fluorophenyl)-1-phenyl-4,5-dihydro-1 H -pyrazole (PZ2) were performed using two successive steps. 3-(4-Ethylphenyl)-5-(4-vinylphenyl)-1-phenyl-4,5-dihydro-1 H -pyrazole (vPZ1) was synthesized using PZ1 fluorophore as staring material and Stille cross coupling reaction, which was reported successfully for other materials Scheme summarizes the organic synthesis routes of the three pyrazole derivatives.…”

Widely Exploited, Yet Unreported: Regiocontrolled Synthesis and the Suzuki–Miyaura Reactions of Bromooxazole Building Blocks

“…Among several known methods for the preparation of 4bromooxazoles, [2,4,30,32,35,[50][51][52][53] we have turned our attention to the LDA-mediated halogen dance reaction of 2-substituted 5bromooxazoles (Scheme 3). [54][55][56] Thus, the advantage of abovedescribed one-pot reaction sequence for the preparation 5bromooxazole (10) might be taken for the synthesis of the previously unknown 4-bromo derivative (11), if LDA-mediated halogen dance step would be added (Scheme 4).…”