Australian Journal of Chemistry

The first azulenyl squaraine dye was reported in 1966, but little activity in the scientific literature has given the impression that they remain unexplored. However, much has been recorded in the patent literature and it is the purpose of this review to bring this record to the attention of researchers.

The present review summarises the latest developments on the ultrasound-assisted synthesis of biologically relevant N-heterocycles at ambient temperature.

The photocatalytic reaction of prepared Bi₂WO₆/g-C₃N₄ composite materials followed a direct solid-state Z-scheme mechanism, which facilitated charge transfer and effectively reduces the recombination of photoinduced electrons and holes, resulting in an enhanced photodegradation efficiency under visible light irradiation.

Bifunctional magnetic–luminescent Fe₃O₄@Y₂O₃:Eu³⁺, Li⁺ composite particles were prepared with Y₂O₃ co-doped with Eu³⁺ and Li⁺ ions as a shell to enhance their luminescence intensity and saturation magnetisation through a urea homogeneous precipitation method.

Different adsorbents (Tenax TA, Porapak Q, and Hayesep Q, among others) were evaluated in a headspace dynamic system containing a mixture of insect semiochemicals. The results demonstrated that Porapak Q and Porapak Rxn RP were able to produce similar ratios of compounds to that of a standard solution with the highest recovery yields.

Unique self-assembled nanoparticles with sea urchin-like pointed edges were synthesized by a solvothermal approach. The high value of the apparent rate constant, k_app, is due to the unique morphology of the Co₃O₄ nanoparticles.

The fluorescence and Raman intensity of poly(3-hexylthiophene) (P3HT)-coated gold nanoparticle arrays with different particle sizes and interparticle distances were enhanced in comparison with pristine P3HT due to electromagnetic field enhancement based on localised surface plasmon resonance (LSPR). The fluorescence and Raman signals of P3HT on gold nanoparticle arrays were gradually enhanced with increasing nanoparticle diameter/interparticle distance ratio.

A custom-designed liquid–liquid countercurrent chromatographic instrument (above left), based on the J-type centrifuge, in which at least one phase contains an ionic liquid, is capable of the separation of inorganic (above right), organic, or bio-based materials on the 0.1–10 g scale.

A polymer, β-MEA, was synthesised from β-cyclodextrin (β-CD), 3-chloro-2-methylpropene (MAC), epoxysuccinic acid (ESA), and 2-acrylamido-2-methyl propane sulfonic acid (AMPS). Its structure, molecular weight, thermal stability, inhibition performance, and mechanism were investigated. The results showed that β-MEA achieves better scale and corrosion inhibition efficiencies compared with poly(aspartic acid) (PASP).

A novel series of 3D Ln^III–Cu^I heterometallic coordination polymers {[Ln₂Cu₄I₃(ina)₇(DMA)₂]_n·nDMA were synthesised by a solvothermal reaction, comprising of inorganic Cu₄I₃ clusters linked by Ln₂(ina)₇(DMA) rod units. The luminescent properties of partial compounds have been investigated in detail.

A simple and sensitive fluorescence probe, based on a substituent coumarin as fluorophore and acrylate as recognition site, is able to selectively and quantifiably detect cysteine over other biothiols such as homocysteine and glutathione.

The co-operative stabilizations associated with the bending of the σ_C–C toward C–F bonds and total hyperconjugative generalized anomeric effect in the cis-configuration of 1,2-difluoroethene overcome the destabilizations associated with the exchange component and dipole–dipole interactions, leading to the preference of the cis-configuration in the compound.

The present paper reports a new hybrid cyclohexaphosphate which was characterized by different techniques (NMR, IR, UV-vis) and evaluated (electrical and biological). This reported compound exhibits an acidic character which is rarely observed with this type of condensed phosphate. In addition, this material is distinguished from others by its higher thermal stability and more pronounced antioxidant activity.

New azomethine receptors were designed and synthesised for rapid and naked eye detection of inorganic fluoride anions in semi-aqueous media. The sensing ability of the receptors towards F^- has been investigated spectroscopically. By using F^- and H⁺ as chemical inputs and the absorbance as output, an INHIBIT logic gate was constructed, which exhibits ‘Write–Read–Erase–Read’ ability without obvious degradation in its optical output.

Grafting from aryldiazonium salts is a popular method for preparing strongly adherent organic coatings on many surfaces. Usually, the coatings are loosely packed disordered multilayers; however, over the past decade, strategies have emerged for generating monolayers. This review describes these approaches, illustrates some of their applications, and highlights the advantages and disadvantages of each.

The reactions of classic iridium and rhodium complexes with iodine(iii) oxidants are described. All reactions resulted in two-electron oxidation. Ligand exchange and anion scrambling were observed in monodentate ligand-containing complexes. In the case of reacting Iⁱⁱⁱ reagents with chelating ligand-containing complexes, no scrambling was observed, leading to the isolation of well-defined complexes.

A new porous 3-dimensional coordination framework containing the novel photoactive ligand 5-((4-tert-butyl)phenylazo)isophthalic acid displays light-dependent spectroscopic properties.

Star-shaped block copolymers based on poly(N-vinylcaprolactam) and functionalized with polyethylene glycol have been synthesized. The star-shaped block copolymers self-assemble spontaneously into aggregates in water and were used to encapsulate methotrexate.

A novel, simple and straightforward combinatorial method for the synthesis of new substituted 3-(arylamino)-6,7-dihydro-1H-indazol-4(5H)-one derivatives has been developed. The synthesis was achieved via a one-pot three-component reaction of aromatic isothiocyanates, substituted 1,3-cyclohexanediones, and hydrazine hydrate in dimethyl sulfoxide.

The generation of a radical species from the reduction of 1-ethylpyridiniuim bromide has been shown to passivate Zn/Zn^II redox after one cycle. Both deposition morphology and nucleation process are also altered in the presence of the radical species.

Two related [Pt(NH₃)₄]²⁺ complexes, [Pt(NH₃)₄](TCNQ)₂·(DMF)₂ (1) and [Pt(NH₃)₄](TCNQ)₂ (2) are characterized using X-ray, electrochemistry, vibrational, and electronic spectroscopy. Unexpectedly, 2 is not a catalyst for the redox reaction of ferricyanide and thiosulfate, and the rationale for this is presented.

Novel 1,3-oxazine hybrids of sesamol and quinoline have been synthesized via one-pot reaction of sesamol/6-hydroxyquinoline, aromatic amines, and formaldehyde. The structures of all the novel compounds were confirmed by spectral data. The structure of the synthesized hybrids was also confirmed by X-ray crystallographic studies.

The electrical impedance of anodically formed iridium oxide is assessed and correlated with the effective electrode area and charge density for bionics applications.

Synthesis and binding behaviour of bile acid-based flavin receptors containing 2,6-diaminopyridine and aromatic moieties are reported. These receptors display significant influence of steric and aromatic π-stacking interactions, along with hydrogen bonding, on their binding with N-(10)-hexylflavin derivative.

Zeolite X base catalysts containing alkali metal ions are prepared from amorphous bamboo leaf ash. The catalysts are found to be highly active in cyanoethylation of methanol under an instant heating environment that mimics microwave fast heating.

An effective, high-yielding strategy for O-glycosylation is studied and applied in solid-phase synthesis.

Oxidations of W(CO)₄(LL) compounds were investigated electrochemically. The electrogenerated radical cations are unstable toward disproportionation, carbon monoxide substitution, and nucleophilic attack. The kinetics of these reactions were examined using a number of techniques including a.c. voltammetry and chronocoulometry. Infrared spectroelectrochemistry was used to characterize two [W(CO)₄(LL)]⁺ species.

Secondary amines react with maleic anhydride under kinetic control across the C=O functionality exclusively. The product changes into N-substituted maleimic acid under thermodynamic control. The Fukui functions determined at the B3LYP/6-31G* level reveal that the carbon atom of the carbonyl group is the hardest site, thus making it the preferred site for the nucleophilic attack.

A novel alkaloid-like compound containing the azabicyclo[3.3.1]nonane core is reported to be the first instance of using the bridged Ritter reaction with hydrogen cyanide. The structure of this unique and unexpected compound was determined with the aid of X-ray crystallography.

Peptide nanofibres with arginine as a building block have been prepared via a self-assembly method and decorated with Cu and Ni nanoparticles. These prepared nanostructural compounds present a unique catalytic activity for the synthesis of 5-substituted 1H-tetrazoles and the N-arylation of amines.

The hydrogenated derivative of levoglucosenone was functionalised at the α-position with aldol chemistry using a series of aromatic aldehydes. The benzylidene derivative was then hydrogenated stereospecifically and the product transformed using a Baeyer–Villiger reaction into (3R,5S)-3-benzyl-5-(hydroxymethyl)-4,5-dihydrofuran-2(3H)-one, a chiral building block that can be used for the synthesis of the protease inhibitor indinavir.

Electrochemical determination of mass-transport parameters is often subject to small errors, which influence the outcomes of voltammetric experiment–theory comparisons. In particular, a perilous situation emerges when a quasi-reversible model with slightly overestimated mass-transport parameters is used to quantify the electrode kinetics for a system that approaches a reversible limit.

The electropolymerisation of N-ethylanilinium trifluoroacetate, a protic ionic liquid (PIL), was carried out, where the PIL served as the monomer precursor, solvent, and supporting electrolyte for the polymerisation process resulting in different morphologies, a greener approach to production, and a highly processable polymer.

An integrated device is developed that incorporates a sensor, readout system, and battery on paper. The electrochromic readout system allows the pH range of a sample solution to be determined visually rather than using an LCD display or voltmeter. The integrated potentiometric sensor and readout system provides a cost-effective and lightweight solution for pH monitoring.

Aerial oxidation of Cd(TCNQ)₂ during slow recrystallization in tetrahydrofuran produced a dicarboxylate ligand–Cd complex, with the N 1s XPS spectrum showing that this chemical transformation is complete.

A simple and highly sensitive method for the detection of hydrogen peroxide in food samples was developed by electrodepositing Cu and MnO₂ onto a g-C₃N₄ coated glassy carbon electrode. The sensor exhibits high selectivity, good stability, and reproducibility.

Different aminoalcohol ligands (TEA, DEA, and MEA) were found to affect the size and optical properties (band gap and emission peak) of ligand-stabilized ZnO quantum dots. Ligands of higher polarity and larger molar volume produce smaller, more monodisperse ZnO quantum dots. As the size of ZnO quantum dots decrease, the optical properties are blue-shifted.

SnFe₂O₄ has been widely used as a magnetic material or catalyst for the oxidative removal of organic pollutants, but never used as an electrode material in lithium ion batteries. In this study, binder-free SnFe₂O₄-rGO hybrid films with both horizontal and vertical channels were fabricated through electrophoretic deposition to present excellent electrochemical performance of lithium ion batteries.

Heterocycles fused to quinoline frameworks widely occur in many biologically active natural products and in medicinally important drugs. Our strategy represents the first collective synthetic concise and efficient entry to nine novel condensed tetracyclic quinolinones by Friedel–Crafts cycliacylations. The simplicity and wide variability of the procedures highlights the efficiency of the methodology for constructing complex fused-ring systems.

The attempted synthesis of a β-keto imidazolidinone nitroxide by oxidation of the β-hydroxy imidazolidinone precursor led to an unexpected ring-opening reaction. A β-fragmentation mechanism is suggested, rather than a Baeyer–Villiger rearrangement.

A simple procedure for the condensation of the bio-derived furfurals, 5-(methyl)furfural (MF) and 5-(chloromethyl)furfural (CMF), with primary amines is described. The experiments were conducted in both batch and flow conditions, with reaction times as short as 60 s. Mild reaction conditions were necessary for CMF in order to selectively react on the aldehyde and not the methyl-chlorine group.

Orpiment (As₂S₃) quantum dots (QDs) were first synthesised through top-down and bottom-up routes, and exhibit strong blue photoluminescence emission. They were effective against murine melanoma B16 cells through induction of apoptosis. Moreover, self-assemblies of orpiment QDs were fabricated by destroying the protective surface ligand layer surrounding the inner orpiment cores by addition of an acid.

The ability of gold anti-arthritic agents and gold nanoparticles to alter production in RAW264.7 macrophages of a number of cellular mediators of inflammation, including reactive oxygen and nitrogen species, interleukin-10 and tumour necrosis factor, have been compared.

In this research, relatively high surface area mesoporous ZnS nanoparticles have been synthesised using two different media. The mechanism of the by-product assisted synthesis of the prepared mesoporous ZnS nanoparticles in EtOH has been investigated using field emission scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, diffuse reflectance spectroscopy, N₂ adsorption–desorption, and FT-IR spectroscopy analyses.

A series of all-trans acceptor–π-donor (acceptor) compounds were conveniently synthesised via the three-step synthetic method Arbuzov reaction, solvent-free Horner–Wadsworth–Emmons reaction, and Mizoroki–Heck reaction. They all exhibit obvious solvatochromic effects, strong two-photon excited fluorescence, and large two-photon absorption cross-sections.

A novel MoO₂ composite supported on mesoporous graphene oxide (m-MoO₂/GO) is successfully synthesised. The introduction of a mesoporous structure into GO sheets not only promotes the catalytic activity, but also makes m-MoO₂/GO more effective in catalysing olefins with a long carbon chain and large ring size.

Crystalline neutral red accelerates microbial methane generation from coal. Industrial scale-up requires knowledge of crystalline polymorphs that may behave differently with methanogens. Temperatures in the dark, subterranean environments where methanogenesis occurs range from 50–70°C, conditions where neutral red crystallises or transforms to a new polymorph.