Sodium Salicylate: An In‐Depth Thermal and Photophysical Study

Abstract

Sodium salicylate (2-hydroxybenzoate) has been fully characterised by single-crystal X-ray diffraction (SCXRD), thermogravimetric analysis in combination with in operando FTIR spectroscopy and GC-MS, as well as by UV/Vis absorption and photoluminescence spectroscopy backed up by DFT calculations. SCXRD revealed a layered crystal structure composed of ionic sheets formed by Na -O contacts sandwiched between π-stacked aromatic rings of the salicylate anion oriented perpendicular to the layer plane. Only weak van der Waals interactions hold the individual sheets together. No solid/solid or solid/liquid phase transitions were observed upon heating, but a three-step decomposition was observed, with the first onset at 245 °C corresponding to concomitant release of CO and phenol. The UV/Vis absorption spectra show temperature-dependent absorption bands at around 305 and/or 345 nm, which according to DFT calculations correspond to the absorption of the carboxylate or phenolate proton transfer species, respectively. In solution, indications of the phenolate species are found only in a very apolar solvent (cyclohexane). Because of excited-state relaxation, emission always occurs from the phenolate structure, which explains the large Stokes shift.

Magnetic, Photo- and Electroluminescent: Multifunctional Ionic Tb Complexes

“…A broad emission with a maximum at 400 nm located in the range of 360–540 nm is observed for the lanthanum compounds. In general, the spectra display very similar features to the one of NaSal 38 which is also shown in Figure 3 (left). This confirms that the origin of the broad band emission of the lanthanum compounds originates from π-π transitions within the salicylate anion, This phenomenon finds its roots in the.…”

“…All lanthanum salts show a strong absorption in the region around 300–350 nm which can be ascribed to π-π transitions of the salicylate anion. 38 In accordance with the absorption maximum derived from the UV–vis absorption spectra (see the example of the absorption spectrum of La(Sal) 3 ·H 2 O and Tb(Sal) 3 ·H 2 O in the SI, Figure S61 ), the excitation wavelength was set to the absorption band of the salicylate ligand (310 nm) to collect the emission spectra presented in Figure 3 (left). A broad emission with a maximum at 400 nm located in the range of 360–540 nm is observed for the lanthanum compounds.…”

“…The latter has shown a high quantum yield under a large range of excitation wavelengths. 38 In addition, highly luminescent and color-tunable salicylate ILs have been studied by us previously. 39 Terbium(III) was chosen as the emitting ion, because it shows in its compound reliable emission of green light in high color purity.…”

Ball Milling to Produce Composites Based of Natural Clinoptilolite as a Carrier of Salicylate in Bio-Based PA11

“…For a mixed matrix membrane (MMM), the gas permeability can be estimated by different theoretical models. The Maxwell model [24] predicts the apparent gas permeability of the MMMs ( P MMM ) by combining the permeability of the continuous matrix ( P m) and of the dispersed phase ( P d) with the volume fraction of the dispersed phase ( φ d):PMMM=Pm·Pd+2Pm−2ϕd(Pm−Pd)Pd+2Pm+ϕd(Pm−Pd).…”

Solid-State Dehydration Mechanism of Diclofenac Sodium Salt Hydrates

“…Sodium API salts often form hydrate crystals in which the water coordination geometry around Na + is more flexible than the structure of the transition metal ion hydrate owing to the s-block atomic nature of Na [12]. This "pseudo-coordination bond" property of Na + -O(water) interactions contributes the specific hydration-dehydration behaviors of sodium API salts [13][14][15][16][17][18][19].…”