Australian Journal of Chemistry

The foreword to this special issue dedicated to Professor Len Lindoy provides a biographical introduction and an account of his distinguished career. It also summarises the articles in the issue, which have been contributed by Professor Lindoy’s many friends and collaborators in Australia and around the world.

A N,N-dibenzylacetoamide derivative of p-tert-octylcalix[4]arene has been synthesised and its solvent extraction of precious metals in nitric acid media was investigated for determining the effects of extractant concentration and its contact time as well as nitric acid concentration in comparison with a N,N-diethylacetoamide derivative.

Thiaoxaaza macrocycles incorporating NO₂S₂ (L¹) and NO₂S₃ (L²) donors were employed and their silver(i) nitrate complexation in solid and solution states was investigated.

The influence of organic backbone on the bonding modes of the dicarboxylates, conformations of the of the long and flexible dipyridyl ligand, and pore size in isoreticular metal–organic frameworks formed by three double pillared-layer Co^II metal–organic frameworks with a pcu topology is discussed.

1-(4,2′:6′,4″-Terpyridin-4′-yl)ferrocene offers a fixed V-shaped N,N″-donor set, but this does not lead to a predictable assembly algorithm; polymer and metalloamacrocycle formations compete. Similar competitive behaviour is observed in coordination assemblies based on 1-(4,2′:6′,4″-terpyridin-4′-yl)ferrocene, with the greater conformational flexibility of the latter adding to the non-predictability of the assembly process.

A series of rare earth (RE) 3-(4′-methylbenzoyl)propanoate (mbp^–) complexes [RE(mbp)₃(H₂O)] (RE = Y, La, Ce, Nd, Ho, Er) have been prepared by either metathesis reactions between the corresponding rare earth chloride and Na(mbp) or protolysis of rare earth acetates by the free acid.

Structures of [Co(NH₃)₆][Ln(dipic)₃] hydrates have been analysed in terms of the weak interactions occurring between the achiral cation and the chiral anions.

Cobalt(ii) complexes with terpyridine-type ligands, [Co(n-pyterpy)₂](ClO₄)₂ (n = 3 (1), 4 (2)), show different molecular assemblies depending on the nitrogen position in the pyridine substituent. The cooperativity estimated from the magnetic behaviour reflects their assembly nature.

In this work, oxidative stress (OS) models of methanol in mice were successfully established. The experimental results clearly demonstrated that methanol could stimulate the production of hydroxyl radicals in the liver of mice to induce OS. Rhubarb and vitamin C were found to have a protective effect on the liver of mice under acute OS.

Nickel–iron hydrogenases produce and consume hydrogen using elaborate electron and proton transport machinery. Although synthetic modelling of nickel–iron hydrogenases has developed rapidly, it has largely ignored aspects of substrate transfer. Reported here are nickel–iron mimics bearing redox-active ferrocenyl ligands, these trinuclear systems representing advanced models of the native enyzmes.

The transition metal complexes of picolylcyanoacetamides with thiocyanate are presented. Discrete tetrahedral, octahedral, and polymeric structures were isolated, and for cobalt(ii) complexes the magnetic susceptibility was measured.

Functionalised ruthenium(ii) bisterpyridine complexes refuse to obey crystal-engineering hydrogen-bond instructions.

Racemic 4 melts above 350°C despite its low molar mass and absence of Pauling hydrogen bonding. X-Ray and Hirshfeld surface analyses reveal excellent complementarity between homochiral molecules of 4, and layers of opposite handedness are linked by the aza-1,3-peri hydrogen interaction. Weak intermolecular forces are discussed in context of the Lipinski ‘rule of 5’ solubility criteria.

Two new triarylamine-based ligands containing the bispyrazolylmethane moiety and their Ru^II terpyridine complexes exhibit interesting electrochemical and spectroscopic properties. In particular, formation of the triarylamine radical cation leads to an electrochemically induced dimerization process.

Electron-withdrawing or hydrogen-bond accepting groups increase the strength of salicylaldehyde hydrazone Cu extractants by three orders of magnitude.

The chemical mutability of metal–organic frameworks (MOFs) is an advantageous feature that allows fine-tuning of their physical and chemical properties. Herein, we report the successful isoreticulation of a MOF by modifying the steric bulk and length of the original ligand separately and in combination.

The current study presents various Co^II bispidine complexes, including a complex with L¹ that reacts with dioxygen to produce a Co^III product with the N³-monodeprotonated tetradentate bispidine fragment and a coordinated picolinate originating from L¹.

The syntheses and structure investigations of four new 3d transition metal complexes with a flexible N₄O₂-donor hexadentate Schiff-base ligand are described. The molecular structures of the Fe^III, Co^III, and Ni^II mononuclear complexes demonstrate distorted octahedral coordination geometry. The Cu^II complex shows a trinuclear structure.

The synthesis and characterisation of two 28-membered, 2,2′-bipyridine-containing macrocycles is reported.

The co-crystallisation of the linear halogen-bond donor 1,4-DITFB with three symmetric dipyridylacetylacetone isomers produces four different halogen-bonded networks.

N,N′-Bis(3-alkoxy-2-hydroxybenzyl)cyclohexane-1.2-diamines (alkoxy = OCH₃, OC₂H₅) form, with zinc acetate and lanthanide nitrate (Ln = Gd, Tb, Er, Yb) in methanol, the isostructural heterodinuclear complexes [Zn(L)(µ-CH₃COO)Ln(NO₃)₂]. In these complexes, zinc(ii) is coordinated by an N₂O₃ donor set with trigonal bipyramidal geometry, whereas the lanthanides possess an O₉ coordination environment in a capped square antiprismatic configuration.

Two novel oxovanadium(iv) compounds were synthesised and characterised. Their crystal structures and anticancer activities were studied. Compound 2 was found to have strong anticancer activities towards A549 (human lung carcinoma cell line).

The synthesis of DAHA-EDTA is a simple two-step high-yielding process. Its use for Cu-64 radiolabelling of the B72.3 whole antibody was investigated. The biodistribution in LS174t tumour-bearing mice showed high uptake in the tumour and rapid clearance from the blood within 24 h.

A series of bis-pyridyl linkers are combined with the {Fe(NCS)₂} motif to form a family of seven coordination polymer analogues with a stacked (4,4)-grid topology. The resulting Fe^II coordination environment is well established to give rise to spin crossover behaviour, yet these materials remain in the high-spin state to low temperature. This comparative study provides insight into the critical influence of framework structure on producing spin crossover.

Crystal structure determination on the mixed ligand complex [Ru(tpy)(L1)](ClO₄)₂ (tpy = 2,2′:6′,2″-terpyridine; L1 = 4′-(ferrocenylmethylaminomethylphenyl)terpyridine) shows the ferrocenyl group to be located as remotely as possible from the Ru^II centre. This may explain the fact that emission from the Ru^II centre is detectable even at room temperature in solution.

Two Q[10]-based supramolecular assemblies were prepared via different approaches, and these Q[10]-based supramolecular assemblies possess porous features that suggest that Q[n]-based compounds could be used to manufacture molecular sieves and sensors and applied in absorption and separation technologies

The proton conductivity of graphene oxide has been reduced by 25 % after three years of aging due to the decrease in oxygen content and interlayer distance.

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 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.

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.

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.

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.

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.

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.

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.

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.

The simultaneous α-iodination and N^β-arylation mechanism of 5-alkyoxy-4-phenylamino-2(5H)-furanone by (diacetoxyiodo)benzene was investigated by means of density functional theory (DFT), selecting 4-(diphenylamino)-5-methoxy-3-iodo-2(5H)-furanone as the calculation model.

The catalytically and geochemically relevant rates of water exchange of four new Co^II and one new Mn^II 2,2′-bipyridine and 1,10-phenanthroline complexes have been determined using the temperature-dependent line broadening of the ¹⁷O NMR signal from the solvent water.

The determination of enantiomeric purity is frequently required in synthetic chemistry. NMR can be used for this purpose if suitable chiral solvating agents are available. Nine new (+)-dehydroabietylimidazolium salts were synthesised and used as efficient chiral solvating agents for resolving several racemic aromatic and non-aromatic carboxylate salts.

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.

Four dual BODIPY-carbazole conjugates (BDPa–d) with various linkers were synthesized. The results suggest that the linkers have significant effect on the photophysical and electrochemical properties of the conjugates. The conjugates show intensive absorption, remarkable Stocks shifts, and suitable HOMO–LUMO energy levels, which are promising for photovoltaic applications.

Methylene violet 3RAX 1 and its derivatives 2–5 were synthesised and characterised. The binding mode between the synthesised compounds and DNA and their DNA photocleavage ability were investigated. The results suggest that the binding mode between methylene violet 3RAX and DNA, its ability to generate singlet oxygen, and DNA photocleavage activity could be changed through modification of the amino group on methylene violet 3RAX.

Cross-linked poly(acrylamide) microspheres, PAMBA, with mean diameters ranging from 169.7 to 525.2 nm were successfully prepared by dispersion polymerisation of acrylamide in an aqueous ammonium sulfate solution with N,N′-methylenebis(acrylamide) as the cross-linking agent and sodium dodecyl sulfate as the stabiliser. The mean diameter of the PAMBA microspheres can be controlled by adjusting the concentration of the stabiliser.

Two luminescent functionalised supramolecular coordination polymers based on an aromatic carboxylic acid ligand exhibit efficient luminescence sensing for Hg²⁺ ions.

A 3D heterometal–organic framework was synthesised. The compound is 2-fold interpenetrating. It displayed good thermal and solvents stability and exhibited high sensitive and qualitative luminescent detection of nitrobenzene. The present study is the first report on the use of an interpenetrating heterometallic metal–organic framework as a luminescent probe for nitrobenzene

The recovery of platinum from acidic solutions was examined and consists of two steps. For each reaction within a step, the rate constants were determined. The first two reactions in step 1 were diffusion controlled unlike the third reaction in step 2 step, which took place at the surface of activated carbon. The results were in excellent agreement to the assumed model.

Lanthanide phosphate nanoparticles were produced under continuous flow in a vortex fluidic device in the presence of polyvinylpyrrolidone. Changes in the morphology of the dandelion-shaped nanoparticles were possible by varying the chain length of PVP, and the rotational speed and tilt angle of the tube in the vortex fluidic device.

The Ru₂ double bond in (RuPz)₂, composed of one σ bond and one π bond, is unravelled by DFT (B3LYP) and WFT (CASSCF and NEVPT2) calculations. The ground state shows a Ru–Ru distance of 2.38 Å, a stretching frequency of 202 cm^-1, and a bonding energy of 30.7 kcal mol^-1. This agrees with experimental results.

Simultaneous temperature measurement by external and internal sensors revealed hidden inhomogeneities within the reaction mixtures of a debated microwave-assisted benzylation involving a 2-substituted pyridine reagent. Rate enhancement could be explained by macroscopic-scale localized heating in the boundary layers close to the vessel surface.

Homologous series of 4,5-disubstituted 2H-[1,2,3]-triazole derivatives were synthesized from chalcones and sodium azide via CuI-catalyzed oxidative cycloaddition reaction in order to characterize their liquid crystalline properties by polarizing optical microscopy and differential scanning calorimetry.

Is formate an energy source? We achieve formate electrooxidation in a practical and convenient way. The precursor of the oxidation is free HCOO^– in fuel liquid rather than Pt-HCOOH. Formate is able to bypass the undesirable poisoning path to alternatively form carbon dioxide.

Degradable polyanhydride-based nanoparticles are synthesized using thiol–ene ‘click’ polymerization followed by emulsification and solvent evaporation. These nanoparticles have tuneable degradation times, can be easily functionalized, and encapsulate payloads that can then be released upon degradation. Such degradable polymer nanoparticles have potential in many nano/bio-theranostic applications.

Ilimaquinone is a biologically active sesquiterpene isolated from Dactylospongia sponges. An intriguing diastereomeric ratio is observed based on an impressive collection of samples. Biosynthetic and ecological considerations stem from this study.

1,2-Diaryl-1,2-disodioethanes are easily prepared, versatile, and tunable diorganometals finding application in 1,2-reductive eliminations as well as in the degradation of several persistent organic pollutants as homogeneous synthetic equivalents of a highly reactive form of Na metal. Further applications as dinucleophiles and bases are also described.

Lignocellulose has gained much interest as a potential renewable energy resource. However, it is hardly soluble. In this study, a non-thermal plasma was applied to dissolution of lignocellulose to ionic liquids. Chemically active species, which were generated by the plasma, induced decomposition of the lignin network, and consequently dissolution of biomass into ionic liquids was accelerated.

The RO–H/H–Si cross-dehydrogenative coupling (CDC) of alcohols and hydrosilanes with high yield (up to 99 %) and chemoselectivity for the production of silyl ethers using alkali metal salts [MN(SiMe₃)₂] (M = Li, Na, K) as pre-catalysts and under ambient conditions is presented.

In this paper, we introduce a novel aptasensor for fast detection of oxytetracycline (OTC), based on a triple helix molecular switch (THMS) complex formation. The limit of detection (LOD) of this sensor was 1.67 and 6.44 nM in phosphate buffer and milk samples, respectively. The sensor also showed a high selectivity towards OTC.

The probe developed in the present study can selectively detect Hg²⁺ ions in live cells and living tissues without interference from other metal ions and the membrane-bound probes, and its quenching constant is 8.73 × 10⁵ M^–1.

The particle diameter distributions of PLLA show that the stabilizer S131 with short lipophilic segment could improve the particle diameter distribution range, compared with the long lipophilic segment of stabilizer S121. With increasing concentration of the stabilizer S131, the particle size decreased and particle distribution became narrow.

The extraction yield of citral from lemon myrtle using cellulose-dissolving ionic liquids was up to 2.1 times higher than that obtained using ethanol. The ionic liquid could be recycled and reused nine times for the extraction of citral.

Hierarchical HZSM-5 were synthesised by controlled desilication in alkaline medium and used as catalyst for the selective oxidation of 2,3,6-trimethylphenol to 2,3,5-trimethyl-1,4-benzoquinone. The combined studies suggested that the nature of the solvent, intrinsic acidity, and shape selectivity of the hierarchical structure ensured high catalytic properties.

Cope rearrangement of bicycle[5.1.0]octa-2,5-diene and its 8-hetero- (N,O,P) and 4,8-dihetero-analogues has been investigated in the gas phase at the B3LYP/6-31+G* level. The results reveal that relative stabilities of the three-membered ring undergoing opening and the three-membered ring being formed as a result of the Cope rearrangement determine the feasibility and rate of the rearrangement.

The fluorescence intensity of CB[7]–PAL, CB[7]–BER, or CB[7]–COP system decreased with increasing amounts of oxaliplatin (l-OHP) added. The trend is attributed to the competition between l-OHP and PAL, BER, or COP molecules for occupancy of the CB[7] cavity.

A series of novel PA6-PEG/Li composites were developed by melt blending the PA6-PEG copolymer (10 wt-% PEG) with three different kinds of colourless lithium salts (LiCl, C₁₈H₃₅LiO₂, LiAc). The PA6-PEG/LiCl composite showed an excellent static dissipation performance of 2.71 × 10⁸ Ω square^–1.

Several indeno[1,2-c]pyridazines were efficiently synthesised using the one-pot, three-component reaction of substituted indanones, arylglyoxalmonohydrates, and hydrazine in the presence of 1,5-diazabicyclo[4,3,0]non-5-ene (DBN) in water at room temperature.

A tetrapyridyl-substituted tetraphenylethylene (TPy-TPE) works as a good fluorescent visualiser for specific staining for cellular imaging and as a DNA marker.