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Summary Background Bedaquiline improves outcomes of patients with rifampicin-resistant and multidrug-resistant (MDR) tuberculosis; however, emerging resistance threatens this success. We did a cross-sectional and longitudinal analysis evaluating the epidemiology, genetic basis, and treatment outcomes associated with bedaquiline resistance, using data from South Africa (2015–19). Methods Patients with drug-resistant tuberculosis starting bedaquiline-based treatment had surveillance samples submitted at baseline, month 2, and month 6, along with demographic information. Culture-positive baseline and post-baseline isolates had phenotypic resistance determined. Eligible patients were aged 12 years or older with a positive culture sample at baseline or, if the sample was invalid or negative, a sample within 30 days of the baseline sample submitted for bedaquiline drug susceptibility testing. For the longitudinal study, the first surveillance sample had to be phenotypically susceptible to bedaquiline for inclusion. Whole-genome sequencing was done on bedaquiline-resistant isolates and a subset of bedaquiline-susceptible isolates. The National Institute for Communicable Diseases tuberculosis reference laboratory, and national tuberculosis surveillance databases were matched to the Electronic Drug-Resistant Tuberculosis Register. We assessed baseline resistance prevalence, mutations, transmission, cumulative resistance incidence, and odds ratios (ORs) associating risk factors for resistance with patient outcomes. Findings Between Jan 1, 2015, and July 31, 2019, 8041 patients had surveillance samples submitted, of whom 2023 were included in the cross-sectional analysis and 695 in the longitudinal analysis. Baseline bedaquiline resistance prevalence was 3·8% (76 of 2023 patients; 95% CI 2·9–4·6), and it was associated with previous exposure to bedaquiline or clofazimine (OR 7·1, 95% CI 2·3–21·9) and with rifampicin-resistant or MDR tuberculosis with additional resistance to either fluoroquinolones or injectable drugs (pre-extensively-drug resistant [XDR] tuberculosis: 4·2, 1·7–10·5) or to both (XDR tuberculosis: 4·8, 2·0–11·7). Rv0678 mutations were the sole genetic basis of phenotypic resistance. Baseline resistance could be attributed to previous bedaquiline or clofazimine exposure in four (5·3%) of 76 patients and to primary transmission in six (7·9%). Odds of successful treatment outcomes were lower in patients with baseline bedaquiline resistance (0·5, 0·3–1). Resistance during treatment developed in 16 (2·3%) of 695 patients, at a median of 90 days (IQR 62–195), with 12 of these 16 having pre-XDR or XDR. Interpretation Bedaquiline resistance was associated with poorer treatment outcomes. Rapid assessment of bedaquiline resistance, especially when patients were previously exposed to bedaquiline or clofazimine, should be prioritised at baseline or if patients remain culture-positive after 2 months of treatment. Preventing resistance by use of novel combination therapies, current treatment optimisation, and patient support is essential. Funding National Institute for Communicable Diseases of South Africa.

We have investigated the structures, electronic properties, hole and electron mobilities of perfluorinated, perchlorinated and percyanated coronene molecules, using the density functional theory (DFT) and Time Dependent DFT (TDDFT) at the B3LYP-D3/6-311++G(d,p) and $$\omega$$ B97XD/6-311++G(d,p) levels and Markus-Hush charge transfer theory. The calculated geometric parameters for coronene and perchlorocoronene are in good agreement with the experimental data. Our theoretical investigations have shown that B3LYP-D3 functional is suitable to well define vibrational assignments for studied molecules. The quantified effect of the complete substitution of peripheral hydrogen atoms with cyanide groups for the key properties relevant for optoelectronic and photonics such as electron affinities, ionization energies, HOMO-LUMO energies, reorganisation energies, optical absorption spectra, and electron mobilities were discussed. Compared to perfluorination and perchlorination, the percyanation of coronene considerably increases the adiabatic/vertical electron affinities (AEAs/VEAs), the electron mobilities, the HOMO-LUMO gap and reduces the LUMO energy level thus indicating an ambipolar behavior and air-stable material. We have discussed the possible implications of cyanide groups as important substitutes for the design of the new organic compounds useful in electronics.

In a bid to develop efficient biochars, we prepared new biochar by the pyrolysis of Ipomoea batatas feedstock for the ultrasonic-aided adsorption of eriochrome black T (EBT) and celestine blue (CB)...

Nearly a half-century after Gouterman classified the UV–vis–NIR spectra of porphyrin derivatives as normal, hyper, or hypso, we propose a heretofore unsuspected “mechanism” underlying hypso spectra. Hypsoporphyrins, which exhibit blueshifted optical spectra relative to normal porphyrins (such as Zn porphyrins), typically involve dn transition metal ions, where n > 6. The spectral blueshifts have been traditionally ascribed to elevated porphyrin eg LUMO (lowest unoccupied molecular orbital) energy levels as a result of antibonding interactions with metal dπ orbitals. Herein, we have found instead that the blueshifts reflect a lowering of the a2u HOMO (highest occupied molecular orbital) energy levels. Electronegative metals such as Pd and Pt transfer smaller quantities of electron density to the porphyrin nitrogens, compared to a more electropositive metal such as Zn. With large amplitudes at the porphyrin nitrogens, the a2u HOMOs of Pd(II) and Pt(II) porphyrins accordingly exhibit lower orbital energies than those of Zn(II) porphyrins, thus explaining the hypso effect. Hypso spectra are also observed for corroles: compared with six-coordinate Al(III) corroles, which may be thought of exhibiting normal spectra, Au(III) corroles, for instance, exhibit blueshifted or hypso spectra.

Presentations that should raise suspicion of secondary hypertension include early-onset, severe or resistant hypertension. A suggestive family history or clinical clues can point to a specific secondary cause. The most common causes and associations are renal disease, primary aldosteronism and obstructive sleep apnoea. Medicines, illicit substances and alcohol may also be responsible. The assessment of patients begins with history taking and examination, to look for clinical clues. Laboratory tests include electrolytes, urea, creatinine and the aldosterone:renin ratio, urinalysis and the urine albumin:creatinine ratio. Abnormal results should prompt further investigation. Initial testing for primary aldosteronism is best done before starting potentially interfering antihypertensive drugs. If the patient is already taking interfering antihypertensive drugs that cannot be stopped, the interpretation of the aldosterone:renin ratio must consider the presence of those drugs. Specialist advice can be sought if needed.

This study presents the fabrication of nanocomposite for the sequestering of Cr(VI) from solution. The nanocomposites were obtained from the molecular sieve and functionalized multiwall carbon nanotubes and further modified with Pentaclethra macrophylla (oil bean tree) stem bark extract. The pristine molecular sieve (MS) and the modified nanocomposite [Pentaclethra macrophylla stem bark extract anchored on molecular sieve (SMP)] adsorbent were characterized by the FTIR, FESEM, XRD, BET, and TGA techniques. The batch adsorption experiment revealed an agitation time of 120 min, 0.02 g dosage, and sorbate pH of 2.0 as optimum conditions for effective use of MS and SMP. Under these conditions a maximum monolayer capacity (qmax) of 135.5 mg g���1 was obtained for SMP, a value that is better compared to many other related absorbent materials. The uptake of Cr(VI) onto MS and SMP was best described by pseudo-first-order and Elovich kinetic models respectively. Meanwhile, the Freundlich model was noticed to sufficiently describe the isotherm data obtained for MS and SMP. The adsorption of Cr(VI) onto MS and SMP was spontaneous, endothermic, and entropy-driven. The reusability of the nanocomposite and its efficient Cr(VI) removal, present SMP as a potent adsorbent for the sequestration Cr(VI) from aqueous solution. nsufficient innovative research on the sequestration of Cr(VI) from the aquatic ecosystem has made Cr(VI) a recalcitrant water contaminant that often affects water sources. In this work, a novel plant anchor-nanocomposite was fabricated from the spent molecular sieve, multi-walled carbon nanotubes, and the extract from the stem bark of Pentaclethra macrophylla. It was envisaged that due to the phytochemical constituent of the modifier, this nanocomposite could also act as potent adsorbents for the treatment of Cr(VI) polluted water. To the best of our knowledge, the application of Pentaclethra macrophylla stem bark extract as a modifier for the green fabrication of nanocomposite has not been reported. The resulting composites showed good uptake capacity for Cr(VI) as well as efficient reusability.

The prominent benefit of granite is owned to its physicochemical property and ubiquitous nature. Vast application of granite which also includes its use as an adsorbent in environmental remediation practice, can also be enhanced. To further enhanced the uptake capacity of granite, nanocomposite consisting of multiwall carbon nanotubes (MWCNTs) and granite was fabricated and further modified using Dialiumguineensestem bark extract. The structure and composition of pristine granite (PG) and modified nanocomposite granite (G) based material were examined and confirmed by the FTIR, Raman, TGA, SEM and XRD. Meanwhile, the specific surface areasof PG (1.268 m2/g) and G (16.57 m2/g) were obtained using the BET surface area analyser. The optimization step revealed that the uptake capacities of PG and G were dependent on solution pH, sorbent dose and contact time. Meanwhile, pseudo-second-order and Elovich kinetic models were noticed to best describe the data for the removal of Cr (VI) by PG and G. Equilibrium isotherm study revealed that Freundlich and Langmuir models fitted well to the experimental data obtained for the uptake of Cr(VI) onto PG and G respectively. Furthermore, electrostaticattraction betweentheDialiumguineense stem bark extract on the surface of G and Cr(VI) influenced the uptake of Cr(VI). On the other hand, the interaction between the plant extract and Cr(VI) may result in the attenuation of Cr(VI) via reduction to Cr(III). Finally, the thermodynamically favoured adsorptive process demonstrated high adsorbent reusability with good stability for Cr(VI) uptake.

BACKGROUND: There are no data comparing the 6–9 month oral three-drug Nix regimen (bedaquiline, pretomanid and linezolid [BPaL]) to conventional regimens containing bedaquiline (B, BDQ) and linezolid (L, LZD).METHODS: Six-month post end-of-treatment outcomes were compared between Nix-TB (n = 109) and 102 prospectively recruited extensively drug-resistant TB patients who received an ˜18-month BDQ-based regimen (median of 8 drugs). A subset of patients received BDQ and LZD (n = 86), and a subgroup of these (n = 75) served as individually matched controls in a pairwise comparison to determine differences in regimen efficacy.RESULTS: Favourable outcomes (%) were significantly better with BPaL than with the B–L-based combination regimen (98/109, 89.9% vs. 56/86, 65.1%; adjusted relative risk ratio [aRRR] 1.35; P < 0.001) and in the matched pairwise analysis (67/75, 89.3% vs. 48/75, 64.0%; aRRR 1.39; P = 0.001), despite significantly higher baseline bacterial load and prior second-line drug exposure in the BPaL cohort. Time to culture conversion (P < 0.001), time to unfavourable outcome (P < 0.01) and time to death (P < 0.03) were significantly better or lower with BPaL than the B-L-based combinations.CONCLUSION: The BPaL regimen (and hence substitution of multiple other drugs by pretomanid and/or higher starting-dose LZD) may improve outcomes in drug-resistant TB patients with poor prognostic features. However, prospective controlled studies are required to definitively answer this question.

In this research, the mechanism and efficiency of Cr(VI) uptake onto Irvingia gabonensis stem bark extract modified silica gel (IGMS) was reported for the first time. The pristine silica gel (PS) and IGMS adsorbents were characterized by the XRD, FTIR, FESEM, EDX, BET, and TGA techniques. The characterizations proved the successful coating of the plant extract onto silica gel. The FTIR spectra showed the Si–O–Si bands present on the silica gel materials. The FESEM revealed an increase in surface roughness of IGMS after coating with the plant extract, while TGA showed a high thermal stability of both PS and IGMS with over 65% of the initial weight retained at 800 °C. The batch Cr(VI) adsorption revealed optimum uptake at pH 2.0, with a maximum monolayer uptake capacity of 23.26–26.18 mg/g for IGMS at temperatures of 295 to 318 K. The kinetic modeling of Cr(VI) uptake onto PS and IGMS was best fitted by the Elovich model in comparison to the pseudo-second-order, pseudo-first-order, and intraparticle diffusion model. The Langmuir and Freundlich isotherms gave the best fit to the adsorption of Cr(VI) onto IGMS and PS, respectively. Adsorption thermodynamics revealed endothermic, increased randomness and spontaneous removal of Cr(VI) onto IGMS and PS adsorbents. The results revealed that Irvingia gabonensis stem bark extract modified silica gel is a viable and highly efficient adsorbent for the removal of Cr(VI) from Cr(VI)-contaminated effluents.

A low-cost adsorbent (Detarium senegalense stem bark extract coated shale (DSMS)) comprising pristine shale (PSH) coated with D. senegalense stem bark extract was prepared and utilized for the adso...

The surface of pristine multiwalled carbon nanotubes (P-MWCNTs) was modified for enhanced adsorption of Cr(VI) using the stem bark extract of Anacardium occidentale as the modifier. The pristine and modified P-MWCNTs were characterized using the XRD, FESEM, Raman, FTIR, TGA and BET surface area analysis. The uptake of Cr(VI) onto Anacardium occidentale modifier-P-MWCNTs (AOMW) was optimized using experimental conditions such as the pH, contact time, adsorbent dosage, adsorbate temperature and initial Cr(VI) concentration. The results showed optimum removal of Cr(VI) ion at pH 2, 180 min and 0.025 g dosage. The thermodynamic studies showed that Cr(VI) adsorption onto the modified AOMW and MWCNTs was spontaneous, feasible and endothermic. The elimination of Cr(VI) was greatly enhanced by the modification step. P-MWCNTs and AOMW showed efficient regeneration and reuse for Cr(VI) uptake after five cycles. These results proved the viability of AOMW for efficient removal of Cr(VI) from polluted aqueous stream.

In this research, a novel green tillite-based adsorbent (CMT) was synthesized by modifying the surface of natural/pristine tillite (PT) with Chrysophyllum albidum stem bark extract for the efficient removal of Cr(VI) from water. The physicochemical characteristics of PT and CMT were assessed by the use of the FTIR, XRD, BET, TGA, and SEM techniques. Cardinal adsorptive parameters such as solution pH, contact time, adsorbent dose, and initial concentration were used to optimize the efficiency of PT and CMT for Cr(VI) adsorption. The Elovich kinetic model was noticed to best describe the uptake of Cr(VI) onto PT and CMT. Hence, chemisorption was the rate-controlling step for Cr(VI) uptake onto both PT and CMT. Meanwhile, the Langmuir maximum adsorption capacity of PT and CMT was 51.06 and 291.8 mg g−1 respectively, which was higher than those obtained for most materials used for Cr(VI) uptake. The Langmuir and Freundlich models best describe the equilibrium adsorption data for PT and CMT respectively. The reusability assessment of PT and CMT showed over 90% of the initial Cr(VI) uptake even after the fifth cycle of reuse. Electrostatic interaction and reduction of Cr(VI) were responsible for the removal of Cr(VI) from water onto the green material. The uptake of Cr(VI) was thermodynamically feasible, entropy-driven, and endothermic on both PT and CMT. The outcome of this study revealed that the anchoring of Chrysophyllum albidum stem bark extract on tillite produced a green adsorbent, which was highly efficient for the removal of Cr(VI) from polluted water.

In this research, zinc oxide nanoparticles (ZnONPs) were prepared via a facile one-pot chemical precipitation approach and applied in the adsorption of bromophenol blue (BRB) and as antifungal agents against the filamentous fungi and plant pathogens; Alternaria alternata CGJM3078, Alternaria alternata CGJM3006 and Fusarium verticilliodes CGJM3823. The ZnONPs were characterized by the UV–Vis, FTIR, XRD, TGA, BET, SEM, TEM, and EDX techniques, which showed efficient synthesis. The characteristics ZnO UV–Vis absorption band was observed at 375 nm, while the XRD showed an average ZnONPs crystalline size of 47.2 nm. The SEM and TEM images showed an irregular shaped and aggregated porous structure of 65.3 nm average-sized ZnONPs. The TGA showed 22.9% weight loss at 800 °C indicating the high thermal stability of ZnONPs, while BET analysis revealed a surface area, pore volume and pore diameter of 9.259 m2/g, 0.03745 cm3/g and 9.87 nm respectively. The Freundlich, pseudo-second-order, and intra-particle diffusion models showed R2 > 0.9494 and SSE A. alternata CGJM 3006 from 25.09 to 36.28 mm. This was followed by the strain F. verticilliodes CGJM 3823 (range from 23.77 to 34.77 mm) > A. alternata CGJM3078 (range from 22.73 to 30.63 mm) in comparison to Bleach 5% (positive control). Additionally a model was proposed based on the possible underlying mechanisms for the antifungal effect. This research demonstrated the potent use of ZnONPs for the adsorption of BRB and as effective antifungal agents.

We present data on the computed lowest unoccupied molecular orbital energy (ELUMO) of two series of Cu(II)-β-diketonato complexes, calculated via density functional theory (DFT). These are correlated to experimental reduction potential data (Epc), obtained by cyclic voltammetry under different experimental conditions (solvent, working and reference electrodes). All calculations were done with the B3LYP functional in the gas phase. Knowledge of the influence of different ligands on the redox potential of copper complexes, as measured by DFT calculated energy data, are very useful. These theoretical correlations are vital in the further design of similar compounds, to be customized for specific applications. The correlations can be used to predict and fine-tune redox potentials prior to synthesis, saving experimental chemists time and laboratory expenses. Redox potentials influence the catalytic property of bis(β-diketonato)copper(II) compounds. New catalysts can therefore be customized with a specific reduction potential and catalytic activity. Further, the Cu(II/I) redox couple is a potential alternative as electrolyte for dye-sensitized solar cells [1] , [2] , [3] . The redox potential of the electrolyte can drastically affect the photovoltage output and should therefore be optimized for efficiency and durability. By adjusting the reduction potential via different ligands on the complex, the properties of copper dyes can be fine-tuned at molecular level. For more insight into the reported data, see the related research article “Synthesis, Characterization, DFT and Biological Activity of Oligothiophene β-diketone and Cu-complexes” published in Polyhedron [4] .

Metallic nanoparticles (NPs) have gained significant attention in recent years due to their efficiency in the adsorption of water pollutants. Except for magnetic NPs, metallic NPs are rarely used in oil sorption studies, due to the difficulty in recovering the NPs from the treated water. This study reports for the first time the application of ZnONPs for oil spill treatment. The ZnONPs were impregnated onto Musa acuminata peel (MP) support to form a novel material (ZnOMP), which was utilized for the sorption of oil from synthetic oil spills. The as-prepared sorbents were characterized by the SEM, EDS, BET, FTIR, FE-SEM, TGA, and XRD techniques. The presence of 31.32-nm average-sized ZnONPs enhanced the oil uptake characteristics, with clear affinity for the oil phase in comparison to the pristine MP. A maximum sorption capacity of 4.146 g/g and 5.236 g/g was obtained for biosorbents MP and ZnOMP, respectively, which was higher than most reported sorbents. The Freundlich model presented the best fit for the isotherm data, while the pseudo-second-order model was most suited for the kinetics. The presence of competing heavy metal ions in solution did not have any significant effect on the oil sorption capacity onto ZnOMP. The sorption mechanism was attributed to absorption and hydrophobic interactions. ZnONPs impregnated onto the biomass enhanced the spontaneity of oil uptake at higher temperatures. Over 82% desorption of the oil contaminant from the biosorbents was achieved during recovery, using petroleum ether and n-pentane as eluents. Concisely, ZnONPs enhanced the uptake and hydrophobic characteristic of MP biomass and showed good recovery and reusability. Thus, the application of ZnONPs impregnated onto biosorbents in oil spill treatment is highly recommended.

Hydroxybenzophenone (HBP) molecules have their applications in commercial sunscreens as an UV chromophore because of their photostability and lack of reactivity after several hours of irradiation. They are usually photoexcited from the ground state chelated enol form to excited state where it undergoes proton transfer to chelated keto form and undergoes dihedral twisting to the ground state twisted keto form before going back to enol form. In this research, the three proposed isomers of five substituted 2-hydroxybenzophenones were modelled with additional three conformational changes in the ground state chelated enol and the results are related to the available experimental observations in solvents acetonitrile, n-dimethylformamide and dimethylsulfoxide. A significant difference in reduction potential, electron affinity and molecular properties was observed within the four ground state conformations and also the two excited-state proton transfer geometries for each of the five derivatives. The nature of the solvents also had significant effects on the electron affinity, HOMO, LUMO and energy bandgap of the molecules. The best possible conformation from the theoretical models that better described the experimental observations is the ground state trans chelated enol (named M1d) because of the close range of its reduction potential values and their strong level of correlation to that of the experiment and also a close range of its λmax values to that of the experiment.

Herein, we reported for the first time the application of silver nanoparticle (AgNP) based sorbent for the sorption of oil from simulated oil-polluted water. An oleophilic natural organic-silver nanocomposite (AgAW) was synthesized in a one-pot system by impregnation of AgNPs on a natural organic sorbent (AW), which was applied for the ultrasonic sorption of oil. The characterizations proved successful synthesis of the nanocomposite containing 18.92 nm average size AgNPs. A shift from the microporous structure (1.184 nm) of AW to the mesoporous structure (2.231 nm) of AgAW was obtained. The impregnated AgNPs enhanced the hydrophobic characteristics of AgAW for the oil phase, with a maximum oil uptake of 2.66 g/g and 6.11 g/g obtained for AW and AgAW respectively. Besides AgAW exhibited higher oil uptake than the pristine AW at variations in pH (2.0–10.0), sonication time (5–60 min), temperature (395–325 K), and oil concentration (200–1000 g/L). The presence of competing Pb(II) and Cd(II) ions in solution did not significantly affect the oil uptake on the sorbents. In addition, successful regeneration of the sorbents using n-pentane and petroleum ether was achieved with over 85.3% oil desorption. In addition, the sorbents were efficiently reused for oil uptake with a slight decrease in oil sorption capacity. The mechanism of oil sorption on AgAW was found to be purely hydrophobic interactions brought about by the impregnated AgNPs. The efficacy of the synthesized AgAW composite for oil spill treatment based on the oleophilic character, high oil uptake as well as the efficient regeneration and reuse was established.

In this work, we study the influence of different metals on the electronic, linear, and nonlinear optical properties of phenalenyl based complexes by using the density functional theory (DFT) method through the functional B3LYP and the basis set 6-31++G(d,p). The experimentally known zinc-ethyl-dimethyl-phenalenyl (ZEP) has a DFT calculated gap energy Egap of 3.12 eV and a second-order static hyperpolarizability γ0 of 106711.86 au. By doping zinc with copper, we have obtained copper-ethyl-dimethyl-phenalenyl (CEP) with a DFT calculated gap energy Egap of 2.43 eV and a second-order static hyperpolarizability γ0 of 142177.38 au. The calculated average polarizabilities, first- and second-order static hyperpolarizabilities show that the molecular structures are promising materials for application in the nonlinear optical (NLO) devices. Hole and electron mobilities are respectively 2 × 10−3 cm2 V−1 s−1 and 51 × 10−3 cm2 V−1 s−1 for the ZEP dimer. Similarly, the CEP holes and electrons mobilities are respectively 14,336 × 10−3 cm2 V−1 s−1 and 2039 × 10−3 cm2 V−1 s−1. These values show that the proposed CEP molecule as well as ZEP have good charge transfer properties that can be used in data storage and electronic devices, thin films, and field effect transistors.

This work was aimed at the synthesis of a hybrid (STpe-AgNP), obtained by impregnation of silver nanoparticles (AgNP) onto Solanum tuberosum peel (STpe), for the ultrasonic assisted adsorption of bromophenol blue (BB) dye. SEM, FTIR, XRD, EDX, TGA and BET techniques were used to characterize the adsorbents. The XRD, SEM and EDX confirmed successful impregnation of AgNPs onto STpe to form the hybrid. The AgNPs impregnated onto the hybrid were found to be water stable at various pH values of 2.0–9.0. Chi-square (χ2 2 > 0.996) showed that the Freundlich model was best fitted among the isotherm models, corroborated by the oriented site model. Kinetic analysis conformed to the intraparticle diffusion and pseudo-first-order rate equations, while thermodynamics displayed a physical, spontaneous and endothermic adsorption process. The presence of competing Pb(II), Ni(II), Cd(II) and Zn(II) metal ions in solution interfered with the adsorption of BB onto the biosorbents. In terms of reusability, STpe and STpe-AgNP showed BB desorption of 91.3% and 88.5% respectively, using NaOH as eluent. Ultra-sonication significantly enhanced the adsorption of BB by both adsorbents, but the impregnation of AgNPs only slightly improved adsorption of the dye from the simulated wastewater. This study also illustrated that pristine STpe biomass waste is a cheap viable option for the decontamination of BB from water.

Electronic and free energy data of density functional theory calculated optimized geometries of the reactants, transition state of the oxidative addition reaction and different reaction products of the [Rh(RCOCHCOCF3)(CO)(PPh3)] + CH3I reactions (R = C4H3S, C4H3S-C4H2S and C4H3S-C4H2S-C4H2S) are presented to illustrate the influence of the amount of thiophene groups, the implicit solvent and dispersion correction on the calculated energies. All calculations were done with the B3LYP functional, in gas as well as in solvent phase, with and without dispersion correction. The data can save computational chemists time when choosing an appropriate method to calculate reaction energies of oxidative addition reactions. Detailed knowledge of energies involved in the oxidative addition reaction of methyl iodide to rhodium complexes have an important implication in catalysis, for example the Monsanto process where methanol is converted to acetic acid catalysed by a rhodium complex. For more insight in the reported data, see the related research article “Synthesis, characterization, electrochemistry, DFT and kinetic study of the oligothiophene-containing complex [Rh((C4H3S-C4H2S)COCHCOCF3)(CO)(PPh3)]”, published in Polyhedron [1] .

The data presented in this article is related to the research article entitled “Electrochemical and electronic properties of a series of substituted polypyridine ligands and their Co(II) complexes” (Ferreira et al., 2019). This data article presents electrochemical data of five polypyridine ligands, as well as of the three redox couples of each of their corresponding five polypyridine-containing Co(II) complexes. All complexes exhibit two Co-based redox couples (CoIII/II and CoII/I), as well as a ligand-based reduction of the Co(I) complex.

DFT calculations show that, due to Jahn-Teller distortion, the d7 [Co(N,N)3]2+ complexes, with S = ½ (N,N = bipyridine or substituted bipyridine ligand) have two longer axial and four shorter equatorial Co-N bonds (elongation Jahn-Teller), while [Co(terpyridine)2]2+ with S = ½, instead has two shorter central (axial) Co-N bonds and four longer distal Co-N bonds (compression Jahn-Teller), since in the latter, the distal Co-N bonds are more flexible than the Co-N axial bonds in the rigid structure of the tridentate terpyridine ligand. The same trend is observed for the related high spin S = 3/2 Co(II) complexes, though less pronounced. The cyclic voltammograms of [Co(terpyridine)2]2+ and a series of the [Co(N,N)3]2+ complexes show at least three chemically as well as electrochemically reversible redox couples, namely CoIII/II, CoII/I and a ligand based reduction of the polypyridine-Co(I) complex. The reduction of the uncoordinated free polypyridine ligand is more than 0.5 V more negative than the reduction of the coordinated ligand in the polypyridine-Co(I) complex.

The data presented in this paper are related to the research article entitled “Electrochemical properties of a series of Co(II) complexes, containing substituted phenanthrolines” (Ferreira et al., 2018) [1]. This paper presents detailed electrochemical data of eight octahedral Co(II) complexes containing functionalized phenanthrolines-ligands. The data illustrate the shift in the CoIII/II and CoII/I redox couples due to different substituents on the phenanthrolines. Polypyridine Co(II) and Co(III) complexes exhibit properties as potential mediators in dye-sensitized solar cells (DSSCs) (Gajardo and Loeb, 2011; Yu et al., 2011) [2], [3]. The ability of a compound to act as a redox mediator to be used in DSSC, depends on the redox potential of the compound (Grätzel, 2005) [4]. Accurate data of the CoIII/II redox couple is presented here.

Electrochemical studies of a series of substituted phenanthroline-Co(II) complexes all show generally similar behaviour, namely a chemically and electrochemically reversible CoIII/II redox couple, as well as a chemically and electrochemically reversible CoII/I redox couple, followed by a ligand-based reduction. Electron donating- or -withdrawing substituents on the phenanthroline ligands which are coordinated to the Co metal, directly influence the electron density on the Co metal, due to good communication between these substituents and the Co metal via the aromatic rings of the heterocyclic substituted phenanthroline-Co(II) complexes, leading to either more negative (for electron donating groups) or more positive (for electron withdrawing groups) redox potentials respectively. Linear relationships relating E°′(CoIII/II) oxidation and E°′(CoII/I) reduction to various experimental and empirical values, as well as to theoretically calculated energies, show that the electron density on Co is linearly influenced by the electronic properties of the ligands attached to the Co metal. All these established relationships can be used in the design of new substituted phenanthroline-Co(II) complexes with specific customized redox properties as required, for example, for the application of such Co(II) complexes as redox mediator for dye-sensitized solar cells.

© 2018 The Authors. The data presented in this paper are related to the research article entitled “Synthesis, characterisation and electrochemistry of eight Fe coordination compounds containing substituted 2-(1-(4-R-phenyl-1H-1,2,3-triazol-4-yl)pyridine ligands, R=CH3, OCH3, COOH, F, Cl, CN, H and CF3.” (Conradie et al., 2019) [1]. This paper presents electrochemical and density functional theory data of 4-phenyl-substituted dichloro(bis{2-[1-(4-R-phenyl)-1H-1,2,3-triazol-4-yl-κN3]pyridine-κN})iron(II) compounds, containing differently substituted 2-(1-(4-R-phenyl)-1H-1,2,3-triazol-1-yl)pyridine ligands (L2 – L9) (Tawfiq et al., 2014) [2]. Density functional theory calculated data of five different structural isomers for each compound, consistently show that the title compounds are octahedral and that the isomer with the chloride atoms, the pyridine nitrogens and the triazol nitrogens trans to each other, has the lowest energy. Natural bonding orbital (NBO) data and quantum theory of atoms in molecules (QTAIM) data of dichloro(bis{2-[1-(phenyl)-1H-1,2,3-triazol-4-yl-κN3]pyridine-κN})iron(II) show origin for the preference of the trans isomer.

This research evaluated the adsorption of celestine blue (CB) onto a novel Solanum tuberosum waste-magnetite nanocomposite (Mt@STB), prepared by an ecofriendly impregnation of magnetite (Mt) nanopa...

Pollution of environmental waters and ecosystems is increasing. Adsorption is an effective technique for water decontamination, but is limited by the cost of commercial adsorbents such as activated carbon. Research has thus focused on the recycling and transformation of biowaste as low-cost, biodegradable adsorbents. In particular, banana peel is promising for commercial use due to its wide availability and efficiency. Here, we review the use of natural banana peel for the biosorption of pollutants from water. We discuss the factors controlling pollutants removal, and the regeneration and reuse of the biosorbent. pH of 5.0 to 7.0 is favorable for the removal of cationic pollutants, while pH of 2.0 to 4.0 is suitable for anionic pollutants. Generally, higher pollutant concentration induces lower removal, whereas higher banana peel dosage induces higher removal. Banana peel exhibits efficient removal of pollutants at various temperatures, with adsorption capacities mostly within 1–100 mg/g. Nitric acid is the most efficient eluent for heavy metal desorption from banana peel. Most studies showed efficient biosorbent reuse up to five cycles and above. We also discuss the thermodynamics, kinetics and isotherms of the adsorption process.

Patients with highly drug-resistant forms of tuberculosis have limited treatment options and historically have had poor outcomes.In an open-label, single-group study in which follow-up is ongoing at three South African sites, we investigated treatment with three oral drugs - bedaquiline, pretomanid, and linezolid - that have bactericidal activity against tuberculosis and to which there is little preexisting resistance. We evaluated the safety and efficacy of the drug combination for 26 weeks in patients with extensively drug-resistant tuberculosis and patients with multidrug-resistant tuberculosis that was not responsive to treatment or for which a second-line regimen had been discontinued because of side effects. The primary end point was the incidence of an unfavorable outcome, defined as treatment failure (bacteriologic or clinical) or relapse during follow-up, which continued until 6 months after the end of treatment. Patients were classified as having a favorable outcome at 6 months if they had resolution of clinical disease, a negative culture status, and had not already been classified as having had an unfavorable outcome. Other efficacy end points and safety were also evaluated.A total of 109 patients were enrolled in the study and were included in the evaluation of efficacy and safety end points. At 6 months after the end of treatment in the intention-to-treat analysis, 11 patients (10%) had an unfavorable outcome and 98 patients (90%; 95% confidence interval, 83 to 95) had a favorable outcome. The 11 unfavorable outcomes were 7 deaths (6 during treatment and 1 from an unknown cause during follow-up), 1 withdrawal of consent during treatment, 2 relapses during follow-up, and 1 loss to follow-up. The expected linezolid toxic effects of peripheral neuropathy (occurring in 81% of patients) and myelosuppression (48%), although common, were manageable, often leading to dose reductions or interruptions in treatment with linezolid.The combination of bedaquiline, pretomanid, and linezolid led to a favorable outcome at 6 months after the end of therapy in a high percentage of patients with highly drug-resistant forms of tuberculosis; some associated toxic effects were observed. (Funded by the TB Alliance and others; ClinicalTrials.gov number, NCT02333799.).

Die reduksie van tris(β-diketonato)mangaan(III) ([Mn(β-diketonato)3]) verbindings na tris(β-diketonato)mangaan(II), asook die oksidasie daarvan tot tris(β-diketonato) mangaan(IV), is ondersoek met behulp van DFT-metodes. Die akkuraatheid van die voorspelling van die reduksiepotensiaal of oksidasiepotensiaal is baie belangrik vir die bepaling van die potensiaalomvang wat geskik is vir die ontwerp van spesifiek vereiste toepassings. Die DFT-funksionele metode M06 het die eksperimentele reduksiepotensiaal tot ‘n hoër vlak van akkuraatheid weergegee, in vergelyking met die M062X en B3LYP metodes. Hierdie studie het ook getoon dat reduksie van verbindings ‘n afname in entropie en ook Gibbs vrye energie, in sowel die gasfase as die oplosmiddelfase, veroorsaak het en gevolglik die hoogste waarde vir totale Gibbs reaksie-energie (ΔGrksie) vir die gereduseerde verbinding getoon het, veral vir dié molekules met sterker elektron-onttrekkende groepe, soos CF3. Dit het gelei tot ‘n reduksiepotensiaalverskuiwing na meer positiewe waardes, vir dié verbindings wat CF3 bevat. Hierdie meer positiewe reduksiepotensiaal van verbindings in die teenwoordigheid van sterker elektrononttrekkende groepe het ook ‘n skuif na meer positiewe oksidasiepotensiaal tot gevolg gehad. Gevolglik kon die oksidasiepotensiaal gaandeweg nie meer binne die eksperimentele venster vir oplosmiddels waargeneem word nie. Die waardes van die molekulêre elektrostatiese oppervlakpotensiaal (MESP) minima en die MESP atoompotensiaal van die Mn atoom en sy gekoördineerde suurstofatome, dien as goeie beskrywers vir die waargeneemde eksperimentele reduksiepotensiaal en kan ook bydra om die eksperimentele reduksie van toekomstige molekules tot ‘n hoë vlak van akkuraatheid te kan voorspel.

We investigated theoretically the structures and relative stabilities of the solvated copper(II) ion in ammonia, Cu2+(NH3)n, n = 1–10. Besides, we reported the temperature dependence of the isomer distribution of the studied clusters. Distances dCu2+–N for the solvated copper(II) ion in ammonia were discussed. Several significant new isomers and new global minimum energy structures of these clusters were pointed out. A satisfactory relative stability rule of the various isomers of this cluster is proposed and we expect it to be extended to other metal ions solvated in other media. It is worth mentioning that the only possible coordination numbers of the solvated copper(II) ion in ammonia are 4, 5 and 6 and these coordination numbers are strongly influenced by the temperature. The theoretical approach used in this work leads to equatorial distances dCu2+–N, in excellent agreement with experimental results. As far as the temperature dependence of the isomer distribution is concerned, compact and highly coordinated structures dominate the population of the studied clusters at all temperatures. For n = 2–5, the most stable isomers dominate exclusively the population of the clusters, irrespective of the temperature. For n ≥ 6, two to three isomers contribute to the population of the clusters. After reporting binding energies, clustering energies, clustering enthalpies and clustering free energies of the studied clusters, we proposed anticipated results for n > 10 through highly correlated fit functions with very low root mean square errors. We also confirm here our previous claim that clustering free energies at modest or higher cluster sizes (n > 7) for solvated metals could not depend on the metal type (alkaline earth, transition metals, …).

Understanding the proton transfer processes in acetonitrile is subjected to the knowledge of the structures of protonated acetonitrile clusters, H+(MeCN)n. Despite their importance, there is no clearly reported investigation of the structures of the protonated acetonitrile clusters, unlike the protonated water clusters or the protonated ammonia clusters. In this work, we thoroughly explored the potential energy surfaces (PESs) of the protonated acetonitrile clusters up to the decamer (n = 10) using three incremental levels of theory. We started by exploring the PESs of the protonated acetonitrile clusters using classical molecular dynamic to generate initial structures. Then, the generated structures have been fully optimized using a density functional theory (DFT) functional, MN15, associated to the 6-31++G(d,p) basis set. Finally, to gain more insights on the location of the global minima energy structures, all the structures of clusters up to the heptamer (n = 7) have been fully re-optimized at the MP2/aug-cc-pVDZ level of theory. As a result, we reported several local and global minima energy structures of the protonated acetonitrile clusters that have not been reported previously. The results show that the structures of the protonated acetonitrile clusters are stabilized by strong H+⋯N hydrogen bonds, anti-parallel dimers, dipole–dipole and CH⋯N interactions. Moreover, we noted that planar and branched isomers are the most favored for clusters lower than the hexamer, while larger-sized clusters favored compact isomers. To derive temperature effects on the stability of the investigated structures, we have reported the temperature-dependent isomer distributions of all the investigated clusters.

Natural-based polyols are seen by polyurethane industries as an alternative to the petroleum-based polyols because of increasing challenges due to the oil crisis and global warming. In this research, four different derivatives of bio-polyols are examined, which include the precursor Jatropha curcas oil (JC) that was extracted from Jatropha curcas seeds, as well as the derivatives epoxidated-polyol (EJ), hydroxylated epoxy-polyol (JP) and epoxy-polyurethane (JU). The computational studies provide more insight into their experimentally observed properties and can be useful in further customized design of this type of bio-polyols for industrial application. Results show that the JU monomer is more stable in terms of potential energy, level of atomic fluctuation, diffusion, radial distribution function, and with properties indicating the possibility of forming the best crystal solid. Monomer JU is also found to have the best resistance to acidic attack, using the results from the interaction energy, radial distribution function (RDF) and level of diffusion.

Reduction of [Fe(TPC)(THF)] (TPC = trianion of 5,10,15-triphenylcorrole) with KC8 generates the iron(II) corrole anion, K(THF)2[FeII(TPC)] (3a). Compound 3a represents the first example of an isola...