Double Acceptor Research Articles

Effect of weak alkaline electrolyzed water on rice cooking: Promoting rapid water absorption and enhancing the quality and digestibility

Promoting the rapid water absorption of rice is beneficial for increasing the cooking quality and digestibility of rice. Under the action of an electric field, weak alkaline electrolyzed water (WAEW) had a smaller cluster system compared to tap water, with a 17.30% decrease in DDAA-OH (double donor-double acceptor) and a 22.89% increase in Free-OH. Therefore, there were fewer hydrogen bonds formed between water molecules, resulting in more free proton donors and proton acceptors, which increased the possibility of forming more hydrogen bonds with other substances. During the soaking process, WAEW could effectively increase the water absorption rate, maximum water content, and water diffusion rate in different types of rice. As WAEW formed more hydrogen bonds with substances in the rice, it was easier to combine with substances in the rice, forming more bound water. Under the combined effect of the alkaline environment of WAEW and the characteristics of its own water molecules, the surface and internal structure of the rice were eroded, the surface layer was peeled off, and a large number of pore structures were formed. Along with the increased water absorption, more substances such as starch and protein dissolved from the rice. The cooked rice soaked in WAEW had greater sensory quality, higher digestibility and glycemic index. Therefore, WAEW could be used as a new method for cooking rice, promoting the rapid absorption of water and increasing the sensory quality and digestibility.

Hydrogen Solubility in Confined Water.

Confined water has demonstrated distinct structural and dynamic properties compared to bulk water. Although many studies have explored the water structure within simple geometries using materials such as carbon and silica, studies on gas solubility in confined water and the underlying physics of water structure-solubility remain limited. Recent research has illuminated the concept of "oversolubility", wherein gases display increased solubility within liquids confined in small pores compared to their bulk form. This study focuses on zeolites, naturally abundant materials with versatile applications, to study the hydrogen solubility within confined water through careful experimentation. Our findings underscore the relationship between the pore dimension and gas solubility enhancement within confined water. Hydrogen solubility is closely associated with the rearrangement of water molecules within the porous framework of the zeolite. Our research shows that a 2 nm pore size results in the greatest increase in hydrogen solubility in the water trapped inside the zeolite framework. The double donor-double acceptor (DDAA) bonds play a critical role in hydrogen solubility. Our research provides fundamental insight into the role of the molecular bonding type on hydrogen solubility in water, paving the way for potential applications in hydrogen storage and utilization.

Metal‐Free Organic Dyes with Double Auxiliary Acceptors for High‐Performance Dye‐Sensitized Solar Cells

Dye‐sensitized solar cells (DSSCs) have continuously received attentions in the field of photovoltaics due to their charming properties and promising performance under the indoor dim‐light environment. Herein, two organic photosensitizers (GZ121 and GZ124) are designed with the insertion of double auxiliary acceptors in a donor‐acceptor‐π‐acceptor‐π‐acceptor (D‐A‐π‐A‐π‐A) design. The devices fabricated from these photosensitizers are investigated under one sun and dim‐light (300–6000 lux) conditions with N719 dye for comparison. The GZ124 dye achieves power conversion efficiencies (PCEs) of 9.43% (photocurrent density (Jsc) = 14.79 mA cm−2, photovoltage (Voc) = 0.85 V, and fill factor (FF) = 0.75) under one sun irradiation and 28.62% (Jsc = 0.99 mA cm−2, Voc = 0.68 V, and FF = 0.77) under dim‐light illumination at 6000 lux, which is far better than the reference N719 dye. Moreover, the PCE under dim light is ranked among the top as compared to DSSCs devices sensitized by a single dye. The GZ124 dye also demonstrates outstanding stability for more than 1000 h under prolonged one sun sensitization. The current studies affirm that the design of a D‐A‐π‐A‐π‐A structural framework by introducing double auxiliary acceptors in a single sensitizer is a promising approach to boost the performance of DSSCs.

Boron-rich hybrid BCN nanoribbons for highly ambient uptake of H2S, HF, NH3, CO, CO2 toxic gases.

Nanomaterials-based gas sensors are widely applied for the monitoring and fast detection of hazardous gases owing to their sensitivity and selectivity. Hydrogen sulfide (H2S), hydrogen fluoride (HF), ammonia (NH3), and carbon monoxide/dioxide (CO/CO2) produced from petroleum fields, sewage, mines, and gasoline are harmful for both human life and environment. With an increase in the emission of these toxic compounds, their real-time monitoring and efficient adsorbent application and storage are very necessary. To this end, we investigated the adsorption characteristic and sensitivity factor of these five toxic gases on armchair and zigzag hybrid boron-carbon-nitride (BCN) nanoribbons with/without boron-rich (B-rich) defects using first principle calculation, where 25%, 33%, and 50% carbon concentration were considered. Our findings reveal that B-rich nanoribbons have strong adsorption energy, charge transfer, and structural deformation owing to the double acceptor of B-rich defects. Moreover, the zigzag and armchair forms of these hybrid BCN nanoribbons show physical adsorption, altering their band gap and phase transition after adsorbing these toxic gases, where B-rich nanoribbons possess high sensitivity to NH3 and CO among other gases. Furthermore, B-rich hybrid nanoribbons have higher CO2 adsorption energy than the standard free energy of CO2 at room temperature. This study suggests that hybrid BCN nanoribbons and B-rich defected structures can be good candidates for the uptake and storage of toxic gases, helping experimental groups to design efficient ambient gas sensors.

Hydrogen bond network structures of protonated 2,2,2-trifluoroethanol/ethanol mixed clusters probed by infrared spectroscopy combined with a deep-learning structure sampling approach: the origin of the linear type network preference in protonated fluoroalcohol clusters.

While preferential hydrogen bond network structures of cold protonated alcohol clusters H+(ROH)n are generally switched from a linear type to a cyclic one at n = 4-5, those of protonated 2,2,2-trifluoroethanol (TFE) clusters maintain linear type structures at least in the size range of n = 3-7. To explore the origin of the strong linear type network preference of H+(TFE)n, infrared spectra of protonated mixed clusters H+(TFE)m(ethanol)n (m + n = 5) were measured. An efficient structure sampling technique using parallelized basin-hopping algorithms and deep-learning neural network potentials is developed to search for essential isomers of the mixed clusters. Vibrational simulations based on the harmonic superposition approximation were compared with the observed spectra to identify the major isomer component at each mixing ratio. It was found that the formation of the cyclic structure occurs only in n ≥ 3 of the mixed clusters, in which the proton solvating sites and the double acceptor site are occupied by ethanol. The crucial role of the stability of the double acceptor site in the cyclic structure formation is discussed.

Comparative Investigation of the Microstructure of MgCl2 Aqueous Solutions Using Different X-ray Scattering Sources, Raman Spectroscopy, and Atomistic Simulations.

Aqueous solutions of magnesium chloride (MgCl2(aq)) are often used to test advances in the theory of electrolyte solutions because they are considered an ideal strong 2:1 electrolyte. However, there is evidence that some ion association occurs in these solutions, even at low concentrations. Even a small ion-pairing constant can have a significant impact on the chemical speciation of ions, so it is important to determine whether ion pairing actually occurs. In this study, MgCl2(aq) with concentrations ranging from 1 to 35% was studied using three methods: X-ray scattering (XRS) with the Shanghai Synchrotron Radiation Facility (SSRF) and silver-anode laboratory sources, Raman spectroscopy, and molecular dynamics (MD) simulations with the COMPASS-II and Madrid force fields. XRS results were analyzed in the framework of PDF theory to obtain the reduced structure function F(Q) and the reduced pair distribution function G(r). The F(Q) values from synchrotron radiation and laboratory sources both showed that the tetrahedral hydrogen bonds in bulk water were destroyed with the increased MgCl2 concentration. The results of G(r) indicated that the main peaks centered at 2.05 and 2.80 Å can be ascribed to the interactions of Mg-O and O-O, respectively. The peak at 3.10 Å is attributed to the combined effect of O-O and Cl-O. By comparing the structural information on MgCl2 solution obtained from the two light sources, it was found that both SSRF and silver-anode laboratory sources can reflect the above-mentioned structural information on MgCl2 solution. The radial distribution function (RDF) obtained from MD simulations of MgCl2 solutions assigned the peaks at 2.0, 2.8, and 3.2 Å to the Mg-O, O-O, and Cl-O interatomic pairs, respectively. The decrease in the O-O coordination number confirms that the hydrogen-bonding network of water is disrupted by increasing MgCl2 observed by X-ray scattering. The proportion of Mg-Cl contact ion pairs gradually increases with MgCl2 concentration as does the coordination number. Raman spectroscopy results show that the bond type changes from double donor double acceptor (DDAA) to single donor-single acceptor (DA) with increasing concentration, providing explicit details of the hydrogen-bond evolution in the aqueous solution.

Modulating excited state properties of thermally activated delayed fluorescence molecules by hybrid long-range and short-range charge transfer strategy

Balancing the rapid radiative decay process and the fast reverse intersystem crossing (RISC) process of thermally activated delayed fluorescence (TADF) molecule remains a great challenge and efficient molecular design strategies are highly desired. Herein, from a theoretical perspective, excited state properties of three reported TADF molecules (1TICz, 1BOICz and 2BOICz) are investigated based on density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations coupled with the thermal vibration correlation function (TVCF) method. Results indicate that, by introducing the multi-resonance (MR) acceptor, 1BOICz possesses hybrid long-range and short-range charge transfer features, balanced small energy gap (ΔEST) and large oscillator strength (f) is obtained. Furthermore, by incorporating double equivalent MR acceptors in 2BOICz, largely enhanced f with slightly changed ΔEST is achieved, inner mechanism for remarkable photophysical property is illustrated. Keep this strategy, seven new TADF molecules (2pDBA-bICz-1, 2pDBA-bICz-2, 2OSBA-bICz, 2DQAO-bICz, 2QAO-bICz, 2SQAO-bICz and 2OQAO-bICz) are theoretically designed, detailed physical parameters are analyzed and excited state energy consumption process is studied. Strong electrophilicity on acceptor is determined and the strength of nucleophilic sites on the bridge-phenyl of 2DQAO-bICz, 2QAO-bICz, 2SQAO-bICz and 2OQAO-bICz is increased, this promotes the short-range charge transfer property. In addition, the excitation processes for all studied molecules are dominated by long-range charge transfer from donor to acceptors, and supplemented by the short-range charge transfer on the bridge-phenyl with MR effect. Compromise energy gap and oscillator strength as well as large spin orbit coupling (SOC) constant are obtained for designed molecules. Thus, by regulating the long-range and short-range charge transfer ratios, excited state properties are successfully modulated and new efficient TADF molecules are proposed. Our research aims to provide deeper insight into long-range and short-range charge transfer features in balancing small ΔEST and large f, which could facilitate the development of novel efficient TADF molecules.

2-{3-Methyl-2-[(2Z)-pent-2-en-1-yl]cyclo-pent-2-en-1-yl-idene}-N-phenylhydrazinecarbo-thio-amide.

The hydro-chloric acid-catalyzed equimolar reaction between cis-jasmone and 4-phenyl-thio-semicarbazide yielded the title compound, C18H23N3S (common name: cis-jasmone 4-phenyl-thio-semicarbazone). Concerning the hydrogen bonding, an N-H⋯N intra-molecular inter-action is observed, forming a ring with graph-set motif S(5). In the crystal, the mol-ecules are connected into centrosymmetric dimers by pairs of N-H⋯S and C-H⋯S inter-actions, forming rings of graph-set motifs R 2 2(8) and R 2 1(7), with the sulfur atoms acting as double acceptors. The thio-semicarbazone entity is approximately planar, with the maximum deviation from the mean plane through the N/N/C/S/N atoms being 0.0376 (9) Å (the r.m.s.d. amounts to 0.0234 Å). The mol-ecule is substantially twisted as indicated by the dihedral angle between the thio-semicarbazone fragment and the phenyl ring, which amounts to 56.1 (5)°, and because of the jasmone fragment, which bears a chain with sp 3-hybridized carbon atoms in the structure. The Hirshfeld surface analysis indicates that the major contributions for the crystal cohesion are: H⋯H (65.3%), H⋯C/C⋯H (16.2%), H⋯S/S⋯H (10.9%) and H⋯N/N⋯H (5.5%).

Phase behavior of sulfolane: Potential implications for transport in groundwater

Sulfolane is a toxic pollutant freely miscible in pure water. However, above benchmark concentrations of sulfate or thiosulfate ions, it behaves as a light non-aqueous phase liquid and separates into either bulk phases or kinetically stable emulsions. Sulfolane droplets bear a negative electrostatic charge, as revealed by electrophoretic measurements. With high sulfate salt concentrations, the counterions screen the negative charge of sulfolane droplets. This promotes droplet coalescence and bulk phase separation, as well as droplet adhesion onto negatively charged mineral substrates such as clay and sand. NaCl does not separate sulfolane from water but favors its partitioning into toluene, as demonstrated by attenuated total reflectance-Fourier transform infrared spectroscopy. Water activity measurements show that sodium sulfate interacts with water more strongly than sulfolane, justifying its ability to displace sulfolane and induce its separation. Both sulfolane and sulfate ions interact with water through hydrogen (H) bonds. Water is comprised of water species that donate and accept a different number of H bonds, depending on other molecules in water. Sulfolane is an H bond acceptor. Therefore, it mainly interacts with double H bond donors that either do not accept H or accept only one H (double donor-single acceptor, DD-SA). ATR-FTIR data indicate that sulfate ions compete with sulfolane more effectively than chlorides for interactions with DD-SA, thereby promoting better separation. Sulfolane phase separation can retard its migration in polluted aquifers. This study reveals the complex behaviour of sulfolane in water, with potential implications for sulfolane transport in groundwater.

Effect of bacterial surfactants on the phase behavior of miscible pollutants in water

Rhamnolipids are bacterial amphiphiles. In addition to emulsifying hydrophobic solvents, they affect the phase behaviour of miscible solvents. In mixtures of toluene and water, rhamnolipids mediate the migration of metal ions (e.g., iron and copper) from the water to the toluene phase. Also, rhamnolipids phase separate the miscible solvent tetrahydrofuran (THF) from water, yielding emulsions even in the absence of toluene. This is because they compete with THF for hydrogen (H) bonding with similar water species. Water is an ensemble of species, including single donors (SD) or double (DD) donors, and single acceptors (SA) or double (DA) acceptors. In pure water, SD-SA and DD-DA have similar abundance and are dominant, as shown by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). With 50–200 g/L rhamnolipids, a water species intermediate between SD-SA and DD-DA is dominant, indicating that rhamnolipid-water interactions mainly occur through this species. This same species primarily interacts with THF, at 50–80% THF. At lower THF percentages, a similar (albeit not identical) species dominates, namely DD-DA, explaining separation. Emulsions are THF in water, as demonstrated by synchrotron mid-infrared spectro-microscopy and confocal microscopy using a hydrophobic dye. Synchrotron small angle X-ray scattering (SAXS) showed that rhamnolipids self- assemble into micelles, which contain THF. These findings have potential implications for miscible pollutant migration in groundwater, and their toxicity to rhamnolipid-secreting bacteria.

Probing the Effect of Photovoltaic Material on Voc in Ternary Polymer Solar Cells with Non-Fullerene Acceptors by Machine Learning.

The power conversion efficiency (PCE) of ternary polymer solar cells (PSCs) with non-fullerene has a phenomenal increase in recent years. However, improving the open circuit voltage (Voc) of ternary PSCs with non-fullerene still remains a challenge. Therefore, in this work, machine learning (ML) algorithms are employed, including eXtreme gradient boosting, K-nearest neighbor and random forest, to quantitatively analyze the impact mechanism of Voc in ternary PSCs with the double acceptors from the two aspects of photovoltaic materials. In one aspect of photovoltaic materials, the doping concentration has the greatest impact on Voc in ternary PSCs. Furthermore, the addition of the third component affects the energy offset between the donor and acceptor for increasing Voc in ternary PSCs. More importantly, to obtain the maximum Voc in ternary PSCs with the double acceptors, the HOMO and LUMO energy levels of the third component should be around (-5.7 ± 0.1) eV and (-3.6 ± 0.1) eV, respectively. In the other aspect of molecular descriptors and molecular fingerprints in the third component of ternary PSCs with the double acceptors, the hydrogen bond strength and aromatic ring structure of the third component have high impact on the Voc of ternary PSCs. In partial dependence plot, it is clear that when the number of methyl groups is four and the number of carbonyl groups is two in the third component of acceptor, the Voc of ternary PSCs with the double acceptors can be maximized. All of these findings provide valuable insights into the development of materials with high Voc in ternary PSCs for saving time and cost.

Photoconductivity spectroscopy of arsenic-related acceptors in HgCdTe

The arsenic impurity is widely considered to be the best choice for p-type doping of HgCdTe ternary alloys, which has been a formidable problem for decades. This work studies the terahertz photoconductivity of Hg1–x Cd x Te with x ∼ 0.22 doped with arsenic and subjected to activation annealing to obtain p-type conductivity. In addition to the inevitable photoexcitation lines of mercury vacancies, which act as double acceptors, the spectra contain a distinctive line associated with the photoexcitation of the arsenic-related acceptor. In contrast to the predictions of the effective mass approximation, the binding energy of the acceptor is found to be about 25 meV. The possible reasons for this unexpectedly high chemical shift, which is not quite consistent with the data recently obtained from photoluminescence and Hall effect measurements, are discussed.

Effects of electric polarization and defect energy levels induced by ion irradiation on the electrical behavior of 4H-SiC Schottky barrier diodes

The effects of electric polarization and defect energy levels induced by C4+ irradiation on the electrical behavior of 4H-SiC Schottky barrier diodes (SBDs) are discussed. The parameters of the SBDs were extracted from capacitance–voltage (C–V) and current–voltage (I–V) measurements, the deep level transient spectroscopy (DLTS) was used to identify defect energy levels. In addition, the dielectric function and energy band structure of 4H-SiC were calculated using a first-principles approach to verify the enhancement of polarization and the origin of the defect energy levels. The results show that the net (donor) carrier concentration (N d) increases with the increase of irradiation fluence, which is caused by the competition between irradiation-induced defects and the polarization effect. On the one hand, Z 1/2 is determined by DLTS. It is related to the doubly negatively (2-|0) charged state of V c (carbon vacancy), which is a double acceptor. The intensity of the Z 1/2 peak increases with increasing irradiation fluence, which means that the defects caused by irradiation should reduce the N d. On the other hand, the polarization effect does exist and it becomes stronger with the increase in the irradiation fluence, which makes the N d increase. Obviously, the polarization effect induced by the irradiation is dominant for N d when the depth of ion penetration is in the shallow layer behind the metal–semiconductor (M–S) interface. Irradiation induced electron traps and an uneven distribution of positively charged centers, which can cause ln(I)-V to exhibit a non-linear component before reaching the turn-on voltage. The series resistance (R s), reverse current (I R) increase and the forward current decreases with the increase in irradiation fluence. All these show that the irradiation causes degradation of Ni/4H-SiC SBD performance.

Role of hydrogen bonding on solvent separation using amphiphilic sorbitan ester

Tetrahydrofuran (THF) and water are miscible and interact trough hydrogen (H) bonds. Span 80 (sorbitan ester) is soluble in THF, but not water. Nonetheless, Span 80 H bonds with water, as shown by attenuated total reflectance – Fourier transform infrared spectroscopy. In pure water, species are single (SD) or double (DD) donors, and single (SA) or double (DA) acceptors. In pure water, SD-SA and DD-DA are dominant and have similar abundance. Span 80 and THF alter the distribution of water species. When THF and Span 80 compete for the same water species, THF separation from water is most effective. Span 80 induces a marked shift of SD-SA to higher wavenumbers, which are close to DD-DA. This species intermediate between DD-DA and SD-SA is dominant, indicating that Span 80 mainly interacts with it. This same species is also dominant in THF-water mixtures containing 50–70% THF. Instead, DD-DA is dominant up to 40% THF, while DD-SA dominate at the highest THF percentages. Bottle tests show that Span 80 separates THF and water into bulk phases with 50–70% THF within 1 hr. In contrast, outside this THF range, emulsions are stable for more than 1 hr, as observed by either light scattering or optical microscopy. In mixtures with 50–70% THF, bulk phase separation occurs within 1 hr, because Span 80 competes with THF for the same water species. Separation is poorer outside of this THF range, where Span 80 and THF interact with different water species.

Competition Between the Two σ-Holes in the Formation of a Chalcogen Bond.

A chalcogen atom Y contains two separate σ-holes when in a R1 YR2 molecular bonding pattern. Quantum chemical calculations consider competition between these two σ-holes to engage in a chalcogen bond (ChB) with a NH3 base. R groups considered include F, Br, I, and tert-butyl (tBu). Also examined is the situation where the Y lies within a chalcogenazole ring, where its neighbors are C and N. Both electron-withdrawing substituents R1 and R2 act cooperatively to deepen the two σ-holes, but the deeper of the two holes consistently lies opposite to the more electron-withdrawing group, and is also favored to form a stronger ChB. The formation of two simultaneous ChBs in a triad requires the Y atom to act as double electron acceptor, and so anti-cooperativity weakens each bond relative to the simple dyad. This effect is such that some of the shallower σ-holes are unable to form a ChB at all when a base occupies the other site.

Performance enhancement in thermally activated delayed fluorescence emitters by multi-fold layout

A series of thermally activated delayed fluorescence (TADF) materials, namely o-Ac2BBP, o-Px2BBP, D-BP-DMAC and D-BP-PXZ, were designed with double acridine (DMAC) or phenoxazine (PXZ) donors and double carbonyl acceptors. Phenylene and biphenylene were selected as the central bridges for these emitters, and each benzene ring on the central bridge was substituted at ortho-sites. The biphenylene bridge based D-BP-DMAC and D-BP-PXZ show 3D dimensional non-planar conformations and multi-fold layout, which result in multiple intramolecular interactions including C–H⋯O hydrogen bonds and C–H···π interactions and finally strongly stabilized and rigidified the whole molecular structures by locking the molecular geometry. As a result, the nonradiative transition rates (knr) were effectively suppressed by 5 times in comparison with the corresponding phenylene bridged analogues, and the photoluminescence quantum yields were increased to over 95%. The green and yellow OLEDs with D-BP-DMAC and D-BP-PXZ as doped emitters exhibited the maximum external quantum efficiencies (EQE) of 24.3% and 17.3%, which are almost double of the corresponding values (13.1% and 9.3%) of the phenylene bridged analogues o-Ac2BBP and o-Px2BBP. These results indicate that to increase molecular rigidity by multi-fold-layout is an effective design strategy to enhance the performance of TADF materials and OLEDs.

Fine analysis of the component effect on the microstructure of LiCl solution

Lithium resources are abundant in Chinese salt lakes, but the high Mg/Li ratio in such aqueous natural sources has brought difficulties to the separation and purification of lithium. Crystallization processes are highly affected by the solution microstructure, which, in turn, depends on its composition. Synchrotron X-ray scattering, Raman spectroscopy, and molecular dynamics simulation methods were used to study the microstructure of aqueous LiCl solutions with different concentrations. In the reduced structure function, F(Q), the double peak around the scattering vector Q = 2.5 Å−1 becomes a single peak, which indicates the addition of LiCl changes the tetrahedral hydrogen bond structure in the aqueous solution. The deconvolution fitting of the Raman spectra show that the DDAA-type (double donor-double acceptor) hydrogen bonds tend to be transformed into DA-type (single donor–single acceptor) hydrogen bonds, confirming that the addition of LiCl breaks the tetrahedral hydrogen bond structure. This hydrogen-bond transformation was confirmed by pair distribution function analysis from molecular dynamics simulations of aqueous KCl solutions. In addition, considering the large number of magnesium ions coexisting with LiCl in the Salt Lake, the microstructure of mixed LiCl-MgCl2 solution was also studied. According to the X-ray scattering results, the peak in the reduced pair distribution function G(r) near r = 3.25 Å shifted from 3.25 Å to 3.10 Å with increased Mg/Li ratio. This change is likely to result from the Cl-O and OO interactions in the mixed aqueous solution. The deconvolution fitting results of Raman spectra show that the DDAA type hydrogen bond increases with the Mg/Li ratio, while the DA + DDA type hydrogen bond decreases. The molecular dynamics results showed that chlorine ions have a higher tendency to form contact ion pairs with Mg2+ than Li+. We propose this to be one of the processes retarding the separation of pure LiCl crystal from mixed LiCl-MgCl2 systems.

Non-Radiative Transitions of Holes on Mercury Vacancies in Narrow-Gap HgCdTe

Mercury vacancies, acting as double acceptors, are the dominant point defects in ternary HgCdTe alloys. Though HgCdTe is one of the leading materials in infrared optoelectronics, the energy spectra of the vacancies are still a matter of some debate. This work investigated the rates at which holes are captured to a singly ionized mercury vacancy via acoustic phonon emission in narrow-gap Hg1−xCdxTe with technologically relevant x~0.22. Combined with the calculated rates of intracenter transitions, the data allow one to predict the most pronounced optical transitions in the emission spectrum of a double-charged acceptor. The results are sustained by the photoluminescence spectroscopy in the terahertz domain, allowing one to identify the emission band that is related to neutral vacancies.

Multimode ultrasound and ternary deep eutectic solvent sequential pretreatments enhanced the enzymatic saccharification of corncob biomass

Corncob (CB) is a valuable agricultural waste in high abundance. It is mainly composed of cellulose, hemicellulose and lignin that link in a complex interlocking matrix. The key to its utilization depends on separating cellulose from lignin and hemicellulose using an environment-friendly and effective pretreatment method to improve glucose yield. The study aimed to investigate the effect of sequential pretreatment of CB with ultrasound (US) in conjunction with ternary deep eutectic solvent (TDES). The US, type and molar ratio of TDES, temperature, and time were optimized. The results showed that under the optimum conditions, US (40 +60 kHz, 60 min) + TDES (ChCl-Gly-LA, 1:1:2, 120 ℃, 3 h), the removal of lignin and hemicellulose were 87.54 % and 67.00 %, respectively, and the recovery of cellulose was 82.18 %. After 72 h of enzymatic hydrolysis , the yield of glucose and xylose were 76.94 % and 41.26 %, respectively. Comparatively, pretreated CB yielded 61.58 % glucose and 26.90 % xylose higher than the untreated. Scanning electron microscopy revealed that the surface of the CB became cracked and rugged. X-ray diffraction showed that the CrI increased significantly from 36 % to 59 %. Fourier transform mid-infrared spectroscopy indicated significant changes in the characteristic functional groups of lignin and hemicellulose. Increases in Tonset, Tendset, Tp, Vmax and decreases in Char at 600 °C all corresponded to increases in thermal stability. These results further confirmed that TDES combined with ultrasonic pretreatment effectively removed lignin and hemicellulose. In conclusion, this approach could greenly and efficiently pretreat CB as a new method for biomass pretreatment. • Double hydrogen bond acceptor (donor) ternary pretreatment DES was studied. • The lignin removal efficiency of ternary DES was higher than binary DES. • TDES containing lactic acid reduced significantly the lignin content. • TDES combined with ultrasonic pretreatment increased lignin removal rate. • TDES combined with ultrasonic pretreatment enhanced sugar yields.

Unravelling the Structure of Peroxides with Antiparasitic Activity: The Relative Impact of a Trioxolane or a Tetraoxane Pharmacophore on the Overall Molecular Structure.

Plasmodium falciparum artemisinin-resistance boosted the quest for novel plasmodial "fast killers," uncovering antimalarial candidates OZ439 and E209, whose peroxide precursors are 1,2,4-trioxolane (1) and 1,2,4,5-tetraoxane (2), differing solely in the pharmacophore (trioxolane or tetraoxane). Combining X-ray crystallography and vibrational spectroscopy, along with Hirshfeld surface analysis and calculations (CE-B3LYP/6-31G(d,p)) of pairwise interaction energies of intermolecular contacts existing in the crystal structure, may deepen the understanding of relative reactivity and properties of these endoperoxides classes. In the crystal, the tetraoxane ring in 2 and the trioxolane-adamantyl fragment in 1 are disordered, with molecules 1 and 2 existing as two distinct, stable conformations. Whereas the dominant C-H⋅⋅⋅O H-bonds in 1 connect an adamantyl C-H and O1 or O2 of the trioxolane ring, in 2 they involve the carbonyl oxygen, acting as a double acceptor from phenyl ring C-H groups. C-H⋅⋅⋅O and C-H⋅⋅⋅π H-bonds define the molecular packing of 2, while C-H⋅⋅⋅H-C van der Waals interactions determine the packing of 1. The dispersive component dominates the interaction energies calculated for the most representative molecular pairs.