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In low- to middle-income communities, the lack of affordability of conventional sanitary products during menstrual cycles can cause psychological and health issues, ultimately affecting their quality of life. It is crucial to develop alternative products that are affordable and accessible to all while also promoting menstrual health and hygiene. Super absorbent polymers (SAPs) are a vital component in current disposable sanitary pads and nappies. However, these SAPs are often non-biodegradable and non-biocompatible. Therefore, the use of eco-friendly materials for the production of SAPs is gaining popularity in the hygiene industry, as it offers a means to reduce the carbon footprint and environmental impact associated with traditional SAPs made from non-renewable petroleum-based materials. SAPs made from polysaccharides often have naturally occurring antibacterial properties, making them appealing for commercial applications in sanitary products such as sanitary pads. In addition, the move toward reusable sanitary pads with antibacterial properties can significantly reduce waste generated by single-use products and prevent the growth of bacteria, improving the safety and hygiene of the product. Furthermore, computational modeling and artificial intelligence are now important tools in SAP synthesis, providing advantages such as predicting polymer properties, rationalizing synthesis pathways, and improving quality control. These tools can reduce synthesis costs by eliminating the need for trial-and-error approaches in polymer synthesis, ultimately promoting more affordable products for end users. Overall, these advancements in polymer synthesis and material design can help to create a more sustainable industry and promote menstrual hygiene and product accessibility to those who need it most. [ABSTRACT FROM AUTHOR]

Two morphologically different porous gold layered on Cu-oxide-based electrochemical sensors were developed for the selective detection of dopamine in the presence of uric acid, ascorbic acid or dextrose. The nanoparticles were prepared by layering Au onto either a cubic or octahedron-shaped Cu-oxide crystal via a galvanic reaction. These were characterized with scanning electron microscopy, energy dispersive X-ray and X-ray photoelectron spectroscopy. The porous structure of the gold over layer was clearly visible on the scanning electron microscopy image while the macro morphology was maintained. X-ray photoelectron spectroscopy confirmed the presence of metallic gold while both CuI (CuO) and CuII (Cu2O) were present in the samples. These two Au/Cu-oxide nanocomposites were used to modify glassy carbon electrodes and were tested for their dopamine sensing ability. Differential pulse voltammetry was used to investigate the selectivity towards dopamine in the presence of different interfering molecules uric acid, ascorbic acid and dextrose). From the differential pulse voltammetry, the lowest limit of detection was found to be 1.1 μM, with a sensitivity of 3.4 μA mM−1 mm−2 in the linear range of 10–250 μM for the porous gold layered covering the octahedron Cu-oxide-modified glassy carbon electrode. [ABSTRACT FROM AUTHOR]

Tungsten carbide-based nano-catalysts (Ni-WC, Co-WC and NiCo-WC) and molybdenum carbide-based nano-catalysts (Ni-MoC, Co-MoC and NiCo-MoC) were synthesised using a carbothermal reduction method. X-ray diffraction, scanning electron microscopy coupled with electron dispersive spectroscopy, x-ray photoelectron spectroscopy and cyclic voltammetry were used to evaluate the prepared electrocatalysts. The cyclic voltammetry results showed that Ni-WC coated electrode displayed the best hydrogen evolution reaction catalytic activity with the lowest overpotential of 1.421 V at a current density of 10 mA cm−2, and a Tafel slope of 135 mV dec−1 which is marginally lower than the benchmark Pt/C coated electrodes. Ni-MoC and Co-MoC coated electrocatalysts also produced current more effectively with a change in potential as compared to the Pt/C coated electrode. The durability test showed Co-WC, NiCo-WC and Ni-MoC coated electrodes to have high stability within a wide range of current densities. [ABSTRACT FROM AUTHOR]

Nuclear magnetic resonance measurements confirm that, as expected, the mer isomer of tris(β-diketonato) cobalt(III) complexes is more stable (mer isomers are more stable because they are less affected by steric hindrance and they have lower dipoles). An excess of the mer isomer or only the mer isomer is experimentally observed. The existence of both fac and mer isomers is predicted by density functional theory calculations. At room temperature, the nuclear magnetic resonance peaks of phenyl-containing mer complexes are broad due to the intermediate rotation of bulky phenyl groups resulting in only the average orientation of the non-equivalent protons in the mer complexes. However, upon heating to 55°C (thus speeding up the rotation) or cooling to −50°C (slowing down the rotation), this broad peak is resolved into three sets of carbon peaks appearing in the 13C NMR spectrum, as well as splitting of the ¹H NMR peaks for the non-equivalent protons in the mer isomer. In solid-state 13C NMR the aromatic rings do not rotate, resulting in the splitting of all the 13C NMR peaks. Two sets of well-defined peaks are observed for the fluorine-containing compound [Co(CF3COCHCOCPh)3] in both the 13C and 19F NMR spectra, indicating that both the fac and mer isomers are present with a ratio of fac:mer = 0.1:1. The X-ray photoelectron spectroscopy measured binding energy of the Co 2p3/2 photoelectron lines are influenced by the subtle electronic (electron-donating or electron-withdrawing) properties of the R groups on the β-diketonato ligands. Various relationships are established between the binding energy of Co 2p3/2 and several physical and density functional theory–calculated properties, confirming good electronic communication (the measurable electronic effect that a molecular fragment has on the physical properties of another molecular fragment in the molecule) of the substituent groups through the pseudo aromatic system of the β-diketonato backbones to the metal. [ABSTRACT FROM AUTHOR]

Several morphologically different Cu-oxide nanocrystals (cube, exposing only the (100) facets; elongated octahedron, exposing only the (111) facets; normal octahedron, exposing only the (111) facets; rounded octahedron, exposing only the (111) facets; truncated edge cube, exposing the (100), (110), and (111) facets) have been prepared. Mixed oxidation state facets were obtained, with the X-ray Photoelectron Spectroscopy revealing that both CuI and CuII are present in the samples. The % CuI and CuII vary for the different morphologies. Morphologies exposing the (111) facet showed the highest % CuI present, with the morphologies exposing the (100) facet showing the least amount of CuI. The glassy carbon electrode's surface was modified with these Cu-oxide nanocrystals and their sensing performance for glucose detection was investigated. The limits of detection (LOD) observed for all the Cu-oxide nanocrystal electrodes were < 2 µM. Electrodes modified with Cu-oxide nanocrystals exposing the (111) facets and having more CuI present in the sample resulted in better glucose detection limits. [ABSTRACT FROM AUTHOR]

p-Cresol as additive to the Grubbs second generation catalyst (GII) allows the cross-metathesis of acrylates with prop-1-en-1-ylbenzenes under conditions that only give the prop-1-en-1-ylbenzene self-metathesis product in the absence of cresol. NMR and IR spectroscopy, MALDI-TOF MS and XPS supported the formation of a ruthenium benzylidene with hydrogen bonds between p-cresol and the chloride ligands of GII. XPS furthermore confirmed p-cresol to increase the binding energies of the GII Ru 3d5/2, 3d3/2, 3p3/2 and 3p1/2 photoelectron lines, whereas 1H NMR spectroscopy indicated the carbene carbon and hydrogen to be shielded. It is thus postulated that p-cresol allows for more facile interaction between electron-deficient compounds and the ruthenium benzylidene by decreasing the electron density on the metal center and increasing the electron density on the carbene. [ABSTRACT FROM AUTHOR]

Abstract: Nano-sized metal hexacyanoferrates of the formula KxMy[Fe(CN)6]z·qH2O, where M = Co, Ni or Cu (and x, y, z and q are stoichiometric numbers), were prepared by reverse emulsion. The resulting nano-materials were characterized utilizing physico-chemical and spectroscopic methods. Evaluation of Fourier-transformed infrared absorption peaks located in the C≡N stretching frequency area 2050-2200 cm−1 confirmed the presence of the metal-cyano-chains with mixed oxidation states for both metals in the samples (FeII/III-C≡N-MII/III). Ratios of the different oxidation states of each metal could be calculated from the X-ray photoelectron spectroscopy data, Co1.12II/Co0.56III:Fe0.44II/Fe0.56III, Ni0.52II/Ni0.46III:Fe0.46II/Fe0.54III and Cu0.65II/Cu1.26III:Fe0.50II/Fe0.50III. After modification of glassy carbon and carbon paste electrodes with the metal hexacyanoferrates, the electrochemical properties of these modified electrodes were investigated by means of cyclic voltammetry. The potential application of these electrodes as electrocatalysts for the oxidation of hydrazine was investigated. Lastly, the use of the metal hexacyanoferrates as potential heterogeneous catalysts for the solvent-free oxidation of benzyl alcohol using the environmentally friendly oxidant, H2O2, was explored.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Abstract: A series of metal hexacyanometallate nanoparticles KxMy[M′(CN)6]z·qH2O, with M=M′=Co (1) or Fe (2), M=Co and M′=Fe (3) and M=Fe and M′=Co (4) were prepared by either co-precipitation or reverse micro-emulsion. These nanoparticles were characterised by ATR FTIR, TEM and XPS, which revealed the presence of CoII/III and/or FeII/III within the compounds. The average binding energies found for the Co 2p3/2 photoelectron lines for CoII and CoIII were ca. 781.7 and 782.9 eV respectively, while the binding energies for FeII and FeIII of the Fe 2p3/2 photoelectron lines were located at 709.5 and 711.4 eV. TEM reveal the particle size ranged between 180 and 520 nm. The eight different compounds’ catalytic activity were tested for the solvent-free oxidation of benzyl alcohol using hydrogen peroxide as the oxidant. The progression of the reaction was monitored using ATR FTIR, by following the appearance of the carbonyl stretching frequency of the oxidation products, which showed the formation of not only benzyl aldehyde but also benzyl benzoate, which is the condensation product of benzyl alcohol and benzoic acid (another oxidation product). The TOF of the catalytic oxidation reaction was correlated with the mean particle diameter, % occurrence of CoII/III and/or FeII/III, total metal electronegativity and the degree of covalence of the Co- and Fe-ligand bond.Graphical Abstract: [ABSTRACT FROM AUTHOR]

A series of ferrocenyl-functionalized β-diketonato manganese(III) complexes, [Mn(FcCOCHCOR)3] with R = CF3, CH3, Ph (phenyl) and Fc (ferrocenyl) was subjected to a systematic XPS study of the Mn 2p3/2 and Fe 2p3/2 core-level photoelectron lines and their satellite structures. A charge-transfer process from the β-diketonato ligand to the Mn(III) metal center is responsible for the prominent shake-up satellite peaks of the Mn 2p photoelectron lines and the shake-down satellite peaks of the Fe 2p photoelectron lines. Multiplet splitting simulations of the photoelectron lines of the Mn(III) center of [Mn(FcCOCHCOR)3] resemble the calculated Mn 2p3/2 envelope of Mn3+ ions well, indicating the Mn(III) centers are in the high spin state. XPS spectra of complexes with unsymmetrical β-diketonato ligands (i.e., R not Fc) were described with two sets of multiplet splitting peaks representing fac and the more stable mer isomers respectively. Stronger electron-donating ligands stabilize fac more than mer isomers. The sum of group electronegativities, ΣχR, of the β-diketonato pendant side groups influences the binding energies of the multiplet splitting and charge transfer peaks in both Mn and Fe 2p3/2 photoelectron lines, the ratio of satellite to main peak intensities, and the degree of covalence of the Mn-O bond. [ABSTRACT FROM AUTHOR]

Ruthenocene-containing β-diketones, RcCOCH2COR with Rc = ruthenocenyl and R = C10F21 (1), CF3 (2), C6F5 (3), C10H21 (4), CH3 (5) and C6H5 (6), were synthesised by Claisen condensation of the appropriate methyl ester with acetylruthenocene, and their spectroscopic, electrochemical and thermal properties were compared. A new synthetic route utilising 1,2,3-benzotriazol-1-ylethanone (9) or 1,2,3-benzotriazol-1-yl(ruthenocenyl)methanone (10) as a reactant, rather than the conventional esters, was found to be more efficient for β-diketone synthesis. The apparent acid dissociation constants, pKa′, of the new ruthenocene-containing β-diketones are 7.14(4) (1, R = C10F21), 9.92(3) (3, R = C6F5) and 10.06(2) (4, R = C10H21). Peak anodic potentials of the ruthenocenyl group of 1–6, pKa′ values and the FTIR ν(C=O) stretching frequencies of the precursor esters, RCOOCH3, correlated linearly with the Gordy scale group electronegativity, χR, of the C10F21 (χC10F21 = 3.04), C6F5 (χC6F5 = 2.46), C10H21 (χC10H21 = 2.43) and other R-groups. An electrochemical study in the non-interacting solvent and electrolyte system CH2Cl2/0.1 mol dm−3 [N(nBu4)][B(C6F5)4] revealed electrochemically irreversible one-electron transfer Rc/Rc+ couples in the potential range 650 ＜ Epa ＜ 1110 mV. Strikingly, reduction of the unstable monomeric 17 electron species, [Rc+(C5H5)(C5H4COCH2COR)], was clearly observed for all β-diketones possessing fluorinated R-groups, even at slow (100 mV s−1) scan rates. The enol isomer of the fluorinated β-diketones had ＞90% abundance under the conditions of study and the first order rate constant of enol to keto conversion varied between 220 and 50 000 s−1 depending on solvent (CDCl3 or CD3CN) and R-groups. Thermal analysis (DSC) of 1 and 4 showed no liquid crystalline mesophase behaviour but definite polymorphism was observed. β-diketones 1 and 4 exist as low temperature polymorphs below 42 °C or 12 °C respectively. The high temperature polymorphs converted to isotropic liquids at 83 °C (compound 1) or 52 °C (compound 4). [ABSTRACT FROM AUTHOR]

The metathesis of 1-hexene and (E)-anethole in the presence of Grubbs 2nd generation catalyst was monitored by in situ 1H NMR spectroscopy at different temperatures (15 °C, 25 °C, and 45 °C) and anethole mol fractions (XAnethole ≈ 0.17, 0.29, 0.5, 0.71, 0.83). Time traces confirmed the instantaneous formation of (E)-1-(4-methoxyphenyl)-1-hexene, the cross-metathesis product. A maximum concentration of (E)-1-(4-methoxyphenyl)-1-hexene is reached fairly fast (the time depending on the reaction conditions), and this is followed by a decrease in the concentration of (E)-1-(4-methoxyphenyl)-1-hexene due to secondary metathesis. The maximum concentration of (E)-1-(4-methoxyphenyl)-1-hexene was more dependent on the XAnethole than the temperature. The highest TOF (3.46 min−1) was obtained for the reaction where XAnethole was 0.16 at 45 °C. The highest concentration of the cross-metathesis product was however achieved after 6 min with an anethole mol fraction of 0.84 at 25 °C. A preliminary kinetic study indicated that the secondary metathesis reaction followed first order kinetics. [ABSTRACT FROM AUTHOR]

The general synthetic strategy towards water-soluble biodegradable drug carriers and the properties that they must have are discussed. The syntheses of water-soluble biodegradable copolymers of lysine and aspartic acid as potential drug-delivering devices, having amine-functionalised side chains are then described. Covalent anchoring of carboxylic acid derivatives of the antineoplastic ferrocene and photodynamically active phthalocyanine moieties to the amine-containing drug carrier copolymers under mild coupling conditions has been achieved utilising the coupling reagent O-benzotriazolyl-N,N,N′,N′-tetramethyluronium hexafluorophosphate to promote formation of the biodegradable amide bond. Even though the parent antineoplastic ferrocene and phthalocyanine derivatives are themselves insoluble in water at pH < 7, the new carrier-drug conjugates that were obtained are well water-soluble. [ABSTRACT FROM AUTHOR]