Structure, Optical, and Thermal Properties of 9, 10-Diphenylanthracene Crystals

Abstract

9,10-diphenylanthracene (DPA) single crystal is a promising scintillator material for fast-neutron detection. Two centimetre-sized polymorph crystals of DPA were grown by melting and solution methods (DPA-Melt and DPA-Solution, respectively), and characterised by single-crystal X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, fluorescence spectroscopy, UV-Vis absorbance spectroscopy, and thermogravimetric/differential scanning calorimetry. The DPA-Melt crystal possessed a P21/n structure, with excitation bands at approximately 331, 348, 367, and 387 nm, and the strongest emission wavelength at approximately 454 nm. On the other hand, the DPA-Solution crystal possessed a C2/c structure, with excitation bands at approximately 335, 353, 372, and 396 nm, and the strongest emission wavelength at approximately 468 nm. The two kinds of DPA crystals have the same molecular formula but different crystal structures, crystal lattice constants, and cell parameters. The theoretical density of the DPA-Solution crystal was 1.239 g/cm3, while that of the DPA-Melt crystal was 1.211 g/cm3. The two types of crystals exhibited the same melting point, but the thermal stability of the DPA-Solution crystal is better than that of the DPA-Melt crystal.

Solution to the Host–Guest Compatibility Problem of Solid Triplet–Triplet Annihilation Photon Upconversion by a Molecular-Anchor Sensitizer Approach

“…Polarized transmission images of the same view showed that these domains had different behaviors of the transmittance, which changed by rotating the polarizer (Figure S27, bottom row). Liu and co-workers reported that two different shapes of the fluorescence spectrum exist for DPA crystals depending on their different crystal structures . The two fluorescence spectra that we observed are probably due to such polymorphism of the DPA crystal, although peak wavelengths are not exactly matched to their values.…”

“…Liu and co-workers reported that two different shapes of the fluorescence spectrum exist for DPA crystals depending on their different crystal structures. 34 The two fluorescence spectra that we observed are probably due to such polymorphism of the DPA crystal, although peak wavelengths are not exactly matched to their values. DPA is also known to occasionally exhibit excimer emission in the solid state with peaks around 510 and 540 nm, but its appearance depends strongly on the morphology.…”

A Single‐Enantiomer Emitter Enabled Superstructural Helix Inversion for Upconverting and Downshifting Luminescence with Bidirectional Circular Polarization

“…In order to investigate the role of steric effect in the formation of penetrated dimers of chiral emitters that lead to helix inversion, a phenyl anthracene group was incorporated into the [2,2]paracyclophane skeleton, resulting in the compound R ‐PCPA. As the dihedral angle between the phenyl and anthracene groups in 9,10‐diphenyl anthracene is known to inhibit intermolecular π‐π stacking, [23] it is expected that the crowded aromatics in R ‐PCPA would prevent the formation of a dependent macroscopic chirality effect. The parameter φ of R ‐PCPA is 0.49, with the phenyl rings exhibiting a crowded structure almost perpendicular to the anthracene groups (Figure S18).…”