RSC Advances

Liu, Li; Ueda, Mariko; Kawaharamura, Toshiyuki

doi: 10.1039/d3ra00359kpmid: 37143909

Antimony doped tin oxide thin films are grown at atmospheric pressure using a home-built mist chemical vapor deposition system, which is an environmental-friendly technique with low energy consumption. For obtaining high quality Sb:SnOx films, different solutions are used to support the film fabrication process. The role of each component in supporting solution is also preliminarily analyzed and studied. In this work, the growth rate, density, transmittance, hall effect, conductivity, surface morphology, crystallinity, component and chemical states of Sb:SnOx films are investigated. Sb:SnOx films prepared at 400 °C using a mixing solution of H2O, HNO3 and HCl show a low electrical resistivity of 6.58 × 10−4 Ω cm, high carrier concentration of 3.26 × 1021 cm−3, high transmittance of 90%, and wide optical band gas of 4.22 eV. X-ray photoelectron spectroscopy analyses disclose that the samples with good properties have high [Sn4+]/[Sn2+] and [O–Sn4+]/[O–Sn2+] ratios. Moreover, it is discovered that supporting solutions also affect the CBM–VBM level and Fermi level in the band diagram of thin films. These experimental results confirm that Sb:SnOx films grown using mist CVD are a mixture of SnO2 and SnO. The sufficient supply of oxygen from supporting solutions leads to the stronger combination of cations and oxygen, and the combination of cations and impurities disappear, which is one of the reasons for obtaining high conductivity Sb:SnOx films.

Vázquez, Valeria; Giorgi, Victoria; Bonfiglio, Fernando; Menéndez, Pilar; Gioia, Larissa; Ovsejevi, Karen

doi: 10.1039/d3ra01520cpmid: 37152583

The full utilization of the main components in the lignocellulosic biomass is the major goal from a biorefinery point of view, giving not only environmental benefits but also making the process economically viable. In this sense the solid residue obtained in bioethanol production after steam explosion pretreatment, enzymatic hydrolysis, and fermentation of the lignocellulosic biomass, was studied for further valorization. Two different residues were analyzed, one generated by the production of cellulosic ethanol from an energy crop such as switchgrass (Panicum virgatum) and the other, from wood (Eucalyptus globulus). The chemical composition of these by-products showed that they were mainly composed of lignin with a total content range from 70 to 83% (w/w) and small amounts of cellulose and hemicellulose. The present work was focused on devising a new alternative for processing these materials, based on the ability of the ionic liquids (IL) to dissolve lignocellulosic biomass. The resulting mixture of biopolymers and IL constituted the raw material for developing new insoluble biocatalysts. Active hydrogels based on fungal laccase from Dichostereum sordulentum 1488 were attained. A multifactorial analysis of the main variables involved in the immobilization process enabled a more direct approach to improving hydrogel-bound activity. These hydrogels achieved a 97% reduction in the concentration of the estrogen ethinylestradiol, an emerging contaminant of particular concern due to its endocrine activity. The novel biocatalysts based on fungal laccase entrapped on a matrix made from a by-product of second-generation bioethanol production presents great potential for performing heterogeneous catalysis offering extra value to the ethanol biorefinery.

Yamazaki, Kiyoyuki; Segawa, Atsushi; Mazaki, Hitoshi; Hiyoshi, Norihito; Mimura, Naoki; Sato, Osamu; Yamaguchi, Aritomo

doi: 10.1039/d3ra01939jpmid: 37143913

Production of aromatic compounds from lignocellulosic biomass has recently been one goal of efforts to establish a sustainable society. We studied cellulose conversion into aromatic compounds over charcoal-supported metal catalysts (Pt/C, Pd/C, Rh/C, and Ru/C) in water at temperatures of 473–673 K. We found that charcoal-supported metal catalysts enhanced conversion of cellulose to aromatic compounds such as benzene, toluene, phenol, and cresol. The total yields of aromatic compounds produced from cellulose decreased in the order: Pt/C > Pd/C > Rh/C > no catalyst > Ru/C. This conversion could proceed even at 523 K. The total yield of aromatic compounds reached 5.8% with Pt/C at 673 K. The charcoal-supported metal catalysts also enhanced conversion of hemicellulose to aromatic compounds.

Walusiak, Benjamin W.; Raghavan, Adharsh; Cahill, Christopher L.

doi: 10.1039/d3ra00996cpmid: 37152557

Halide perovskites provide a versatile platform for exploring the effect of non-covalent interactions, including halogen bonding, on material properties such as band gap, luminescence, and frontier orbital landscape. Herein we report six new zero-dimensional tellurium iodide perovskite derivatives, consisting of [TeI6]2− octahedra charge balanced by one of several X-Py cations (X = H, Cl, Br, I, and Py = pyridinium). These compounds also feature robust halogen bonding between [TeI6]2− octahedra and polyiodides in the form of I2 (1–4), I3− (5), or adjacent octahedra (4 and 6). These relatively strong non-covalent interactions (NCIs) are modeled by natural bond order (NBO) and second order perturbation theory (SOPT) calculations. NCIs are responsible for reducing the bandgap of these materials (measured via diffuse reflectance spectroscopy) relative to those without polyiodide species. They also affect inner sphere bonding in the metal halide, exacerbating [TeI6]2− octahedron asymmetry as compared to previously published compounds, with greater asymmetry correlating with higher van der Waals overlap of halogen–halogen contacts. We also demonstrate the ability of hydrogen and carbon bonding (which dominates in the absence of polyiodides) to affect inner sphere tellurium iodide bonding and octahedral symmetry.

Mokhtar, Nur Aina Izzati Mohd; Ashari, Siti Efliza; Zawawi, Ruzniza Mohd

doi: 10.1039/d3ra01060kpmid: 37152575

Lipase has been gaining attention as the recognition element in electrochemical biosensors. Lipase immobilization is important to maintain its stability while providing excellent conductivity. In this study, a lipase electrochemical biosensor immobilized on a copper-centred metal–organic framework integrated with reduced graphene oxide (lipase/rGO/Cu-MOF) was synthesized by a facile method at room temperature. Response surface methodology (RSM) via central composite design (CCD) was used to optimize the synthesis parameters, which are rGO weight, ultrasonication time, and lipase concentration, to maximize the current response for the detection of p-nitrophenyl acetate (p-NPA). The results of the analysis of variance (ANOVA) showed that all three parameters were significant, while the interaction between the ultrasonication time and lipase concentration was the only significant interaction with a p-value of less than 0.05. The optimized electrode with parameters of 1 mg of rGO, 30 min ultrasonication time, and 30 mg mL−1 lipase exhibited the highest current response of 116.93 μA using cyclic voltammetry (CV) and had a residual standard error (RSE) of less than 2% in validation, indicating that the model is suitable to be used. It was characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FTIR), where the integration of the composite was observed. Immobilization using ultrasonication altered the lipase's secondary structure, but reduced its unorderly coils. The electrochemical and thermal analysis showed that the combination of Cu-MOF with rGO enhanced the electrochemical conductivity and thermostability.

Agius, Nicola'; Magri, David C.

doi: 10.1039/d3ra02704jpmid: 37143912

The fluorescent natural products, quinine, quinidine, cinchonine and cinchonidine are demonstrated as H+-enabled, halide-disabled (Cl−, Br− or I−) INHIBIT and INHIBIT-OR combinatorial logic gates in water. More fluorescent natural products with intrinsic logic properties await to be discovered.

Zhang, Yulong; Guo, Huichuang; Wu, Qian; Bi, Xiaojing; Shi, Enxue; Xiao, Junhua

doi: 10.1039/d3ra02430jpmid: 37181505

α,β-Unsaturated esters are key structural motifs widely distributed in various biologically active molecules, and their Z/E-stereoselective synthesis has always been considered highly attractive in organic synthesis. Herein, we present a >99% (E)-stereoselective one-pot synthetic approach towards β-phosphoroxylated α,β-unsaturated esters via a mild trimethylamine-catalyzed 1,3-hydrogen migration of the corresponding unconjugated intermediates derived from the solvent-free Perkow reaction between low-cost 4-chloroacetoacetates and phosphites. Versatile β,β-disubstituted (E)-α,β-unsaturated esters were thus afforded with full (E)-stereoretentivity by cleavage of the phosphoenol linkage via Negishi cross-coupling. Moreover, a stereoretentive (E)-rich mixture of a α,β-unsaturated ester derived from 2-chloroacetoacetate was obtained and both isomers were easily afforded in one operation.

Qi, Weijun; Huang, Yu; Ma, Yuting; Yu, Zizhou; Zhu, Xinbao

doi: 10.1039/d3ra00222epmid: 37143910

Many natural compounds and imidazoline derivatives have been previously evaluated as eco-friendly corrosion inhibitors for application in the food, pharmaceutical and chemical industries. Herein, a novel alkyl glycoside cationic imaginary ammonium salt (FATG) was designed via the grafting of imidazoline molecules into the skeleton of a glucose derivative, and its effects on the electrochemical corrosion behavior of Q235 steel in 1 M HCl were systemically investigated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curves (PDP), and gravimetric measurements. The results indicated that its maximum inhibition efficiency (IE) was 96.81% at a concentration as low as 500 ppm. The adsorption of FATG on the Q235 steel surface followed the Langmuir adsorption isotherm. The scanning electron microscopy (SEM) and diffraction X-ray (XRD) results suggested the formation of inhibitor film on the metal surface, which significantly impeded the corrosion of Q235 steel. Additionally, FATG showed a high biodegradability efficiency (98.4%), which had great potential as a green corrosion inhibitor based on concepts of greenness and biocompatibility.

Nair, Rahul Ramesh; Kißling, Patrick A.; Schaate, Andreas; Marchanka, Alexander; Shamsuyeva, Madina; Behrens, Peter; Weichgrebe, Dirk

doi: 10.1039/d3ra01911jpmid: 37143911

The porous non-graphitizing carbon (NGC) known as biochar is derived from the pyrolytic conversion of organic precursors and is widely investigated due to its multifunctional applications. At present, biochar is predominantly synthesized in custom lab-scale reactors (LSRs) to determine the properties of carbon, while a thermogravimetric reactor (TG) is utilized for pyrolysis characterization. This results in inconsistencies in the correlation between the structure of biochar carbon and the pyrolysis process. If a TG reactor can also be used as an LSR for biochar synthesis, then the process characteristics and the properties of the synthesized NGC can be simultaneously investigated. It also eliminates the need for expensive LSRs in the laboratory, improves the reproducibility, and correlatability of pyrolysis characteristics with the properties of the resulting biochar carbon. Furthermore, despite numerous TG studies on the kinetics and characterization of biomass pyrolysis, none have questioned how the properties of biochar carbon vary due to the influence of the starting sample mass (scaling) in the reactor. Herein, with a lignin-rich model substrate (walnut shells), TG is utilized as an LSR, for the first time, to investigate the scaling effect starting from the pure kinetic regime (KR). The changes in the pyrolysis characteristics and the structural properties of the resultant NGC with scaling are concurrently traced and comprehensively studied. It is conclusively proven that scaling influences the pyrolysis process and the NGC structure. There is a gradual shift in pyrolysis characteristics and NGC properties from the KR until an inflection mass of ∼200 mg is reached. After this, the carbon properties (aryl-C%, pore characteristics, defects in nanostructure, and biochar yield) are similar. At small scales (≲100 mg), and especially near the KR (≤10 mg) carbonization is higher despite the reduced char formation reaction. The pyrolysis is more endothermic near KR with increased emissions of CO2 and H2O. For a lignin-rich precursor, at masses above inflection point, TG can be employed for concurrent pyrolysis characterization and biochar synthesis for application-specific NGC investigations.

Bhargavi, Dodda; Konduri, Srihari; Prashanth, Jyothi; Pulipati, Sowjanya; Praneeth, K. K.; Sireesha, Malladi; Rao, Koya Prabhakara

doi: 10.1039/d3ra00713hpmid: 37152580

We identified twenty-two new sacubitril derivatives (5a–v) as lead compounds for various biologically active targets. These compounds were synthesized by reacting an intermediate compound (2R,4S)-5-([1,1′-biphenyl]-4-yl)-4-(amino)-2-methylpentanoic acid ethyl ester hydrochloride with respective carboxylic acid (RCOOH). The molecular structures of all the newly synthesized compounds were determined by 1H and 13C NMR, ESI mass spectrometry, FTIR spectroscopy, and CHN analysis. Moreover, compound 5n was characterized by a single-crystal X-ray diffraction (SXRD) study to confirm the structure obtained from spectral data. All these compounds were screened for various biological functions such as antifungal, antibacterial, and anti-TB activities. Among these twenty-two compounds (5a–v), some exhibited good to moderate anti-bacterial properties. Similarly, some compounds showed moderate anti-TB and antifungal activities. In addition, the anti-TB activity of compound 5q was estimated against M. tuberculosis in a nutrient starvation model (NSM). Similarly, toxicity was examined against RAW 264.7 cells. These biological activity studies were also correlated with molecular docking studies.