Revealing the Role of Tin(IV) Halides in the Anisotropic Growth of CsPbX3 Perovskite Nanoplates

CsPbX₃ perovskite nanoplates (PNPLs) were formed in a synthesis driven by SnX₄ (X=Cl, Br, I) salts. The role played by these hard Lewis acids in directing PNPL formation is addressed. Sn⁴⁺ disturbs the acid–base equilibrium of the system, increasing the protonation rate of oleylamine and inducing anisotropic growth of nanocrystals. Sn⁴⁺ cations influence the reaction dynamics owing to complexation with oleylamine molecules. By monitoring the photoluminescence excitation and photoluminescence (PL) spectra of the PNPLs grown at different temperatures, the influence of the thickness on their optical properties is mapped. Time‐resolved and spectrally resolved PL for colloidal dispersions with different optical densities reveals that the dependence of the overall PL lifetime on the emission wavelength do not originate from energy transfer between PNPLs but from the contribution of PNPLs with distinct thickness, indicating that thicker PNPLs exhibit longer PL lifetimes.     

RNA separation by in-capillary denaturing polymer electrophoresis with 1,2,5-thiadiazole as an additive

1,2,5-Thiadiazole improved RNA separation with in-capillary denaturing polymer electrophoresis. 1,2,5-Thiadiazole was synthesized as an extraction solvent substituted for a halogenated solvent. While 1,2,5-thiadiazole was an excellent extraction solvent and an environmentally friendly solvent, we found that 1,2,5-thiadiazole was a strong hydrophobic compound for RNA and the RNA separation performance by in-capillary denaturing polymer electrophoresis was dramatically improved. We suggest "in-capillary denaturing polymer electrophoresis" as an RNA separation that realizes the denaturing and separation simultaneously. RNA separation by the method required a strong denaturant, acetic acid, to cleave the intramolecular hydrogen. The running buffer containing acetic acid was of high conductivity and low pH, in which the condition introduced Joule heating and low sensitivity. While conventional denaturants, formaldehyde and urea, maintained small electric conductivity and neutral pH, these denaturants were too weak to achieve the RNA separation by in-capillary denaturing polymer electrophoresis. 1,2,5-Thiadiazole being a neutral molecule, both conductivity and buffer pH were able to be adjusted to a desirable strength for RNA separation. In this paper, we report that RNA separation by in-capillary denaturing polymer electrophoresis in neutral pH was achieved and the sensitivity for RNA separation was higher than that for RNA separation by in-capillary denaturing polymer electrophoresis with acetic acid.     

Conformational effects on mesophase stability: numerical comparison of carborane diester homologous series with their bicyclo[2.2.2]octane,cyclohexane and benzene analogues

Three series of diesters of 4‐alkoxyphenols containing 12‐vertex p‐carborane (1A[n], n = 1–22), 10‐vertex p‐carborane (1B[n], n = 1–12) or bicyclo[2.2.2]octane (1C[n], n = 1–12) as the central structural element were prepared and investigated by optical and calorimetric methods. All carborane diesters exhibited exclusively nematic behaviour, whereas the carbocyclic analogues 1C[n] and also cyclohexane (1D[n]) and benzene (1E[n]) derivatives, showed early onset of SmA phase and complete disappearance of nematic behaviour. The isotropic transition temperatures, T _MI, for the five series of mesogens were analysed numerically using a three‐parameter exponential function. The resulting limiting values, T _MI(∞), provided a quantitative assessment of the central element ability to support the mesogenic state. They demonstrated that, whereas the T _MI(∞) values for the carbocycles, C, D, and E, are around 125°C, for carboranes A and B this value is 70±2°C and 49±19°C, respectively. Two types of comparative analysis of trends in T _MI relative to those of the terephthalate series 1E[n] demonstrated abnormal behaviour of both carborane series (1A[n] and 1B[n]) and also the cyclohexane series (1D[n]). The former showed progressive destabilisation of the mesophase, whereas the series 1D[n] exhibited increasing mesophase stability relative to 1E[n] with increasing chain length. Both of these effects were explained using conformational analysis of theoretical models and experimental molecular structures for 1A[3], 1B[4] and 1C[4]. The increasing relative destabilisation of the mesophase in the carborane derivatives was rationalised by the high order rotational axes in A and B and D _4d symmetry for B. The trend of the ΔT _MI values for series 1D[n] was explained with the existence of the equatorial‐axial conformational equilibrium for the cyclohexane derivatives. The clearing temperatures for the hypothetical pure diequatorial conformers 1D[n]‐ee were estimated.     

Preparation and evaluation of magnetic carbonaceous materials for pesticide and metal removal

When diluted solutions of giant micelles are under turbulent flow, large attenuations of the turbulence can be observed due to the action of the micelles on the dissipative vortices formed within the flow. This particular property is rapidly lost when the solution is heated due breakup of the giant micelles. Based on this property, we present a thermal-flow study of a mixed giant micelle formed by the combination of two surfactants and sodium salicylate. One of the surfactants, cetyltrimethylammonium bromide (C(16)TAB) was kept fixed, and the others were dodecyltrimethylammonium bromide (C(12)TAB), tetradecyltrimethylammonium bromide (C(14)TAB), octadecyltrimethylammonium bromide (C(18)TAB), polyoxyethylene (10) oleyl ether (Brij 97) or sodium dodecyl sulfate (SDS). Thermal diagrams for the combinations of the surfactants reveal deviations of the ideality. For the cationic surfactants, a synergistic effect was only observed when C(16)TAB was combined with the shorter surfactants.     

Experimental and theoretical determination of the stopping power of ZrO<Subscript>2</Subscript> films for protons and <Emphasis Type="Italic">α</Emphasis>-particles

We report the results of an experimental-theoretical study on the stopping power of ZrO₂ films for swift H and He ion beams. The experiments, using the Rutherford Backscattering technique, were done for protons with incident energies in the range 200–1500 keV and for α-particle beams with energies in the range 160–3000 keV. The theoretical calculations were done in the framework of the dielectric formalism using the MELF-GOS model to account for the ZrO₂ target electronic response. It is shown that for both ion beams, the agreement between theory and experiment is quite remarkable.