New Efficient Organic Scintillators Derived from Pyrazoline

Abstract

We report on the synthesis, spectroscopic and scintillation properties of three new pyrazoline core based fluorophores. Fluorescence properties of the fluorophores have been studied both in a solution state and in a solid polyvinyltoluene (PVT) resin matrix of different porosity. The synthesized fluorophores were found to be promising candidates for application in plastic scintillators for detection of ionizing radiation (alpha, beta particles, γ rays and neutrons) and demonstrated superior efficiency in comparison to the existing commercially used fluorophores (2-(1-naphthyl)-5-phenyloxazole (αNPO), 9,10-diphenylanthracene, etc.). Moreover, the suggested synthetic route allows functionalization of the fluorophores with a vinyl group for further covalent bound to the PVT or other vinyl polymer matrices, which dramatically improves chemical stability of the system simultaneously improving the photoluminescence quantum yield. Possible mechanisms of the enhanced scintillation properties are discussed based on preliminary quantum mechanical calculations and spectroscopic characteristics of the fluorophores under study.

Plastic Scintillators and Radiation Detectors Based on Triphenyl Pyrazoline Derivatives

“…PZ−X fluorophores or commercial 2‐(1‐naphthyl)‐5‐phenyloxazole (αNPO) (Fluka) has been used in concentration 0.1 to 1 wt.%. Synthesis of PZ−X fluorophores and their vinyl‐terminated derivative has been described in our previous publication [14] …”

“…Synthesis of PZÀ X fluorophores and their vinyl-terminated derivative has been described in our previous publication. [14] Synthesis of Gd 2 O 3 NP with the average size ~3 nm was performed in accordance to protocol described in literature [15] . Depending on the loading with NP the dispersion appeared to be clear (< 2 % NP) or translucent (3-10 % NP).…”

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.…”

1,5-Diaryl-3-Benzimidazolyl-2-Pyrazolines and Pyrazoles – Novel Fluorescent Dyes of Pyrazoline Family

“…Derivatives of 2-pyrazoline with aryl radicals in positions 1, 3 and 5 are known from the middle 50-th as blue-to-green fluorescent dyes, possessing relatively high quantum yields [1,2]. During decades of their history, fluorescent pyrazolines had found wide practical application as optical brightening agents [3,4], spectra shifters in scintillation techniques [5,6], components of electroluminescent devices [7][8][9], fluorescent ligands for metals cations [10][11][12][13][14], intracellular pH probes [15,16], etc. They were extensively studied in the crystalline state [17], polymer matrices [9,18], in Langmuir-Blodgett films [19] and in donor-acceptor molecular complexes with electron-deficient compounds [20,21].…”