Halide-triggered assembly and selective bisulfate recognition in a quadruply interlocked coordination cage.

Interlocked coordination cages are a class of multi-cavity architectures with applications in selective anion recognition, adaptive sensing, and catalysis. Controlling the partitioning of their cavities through ligand design and appropriate anion templates is critical to their guest binding scope, yet remains a challenge. Here, we present a thermodynamically stable [PdL](BF) cage assembled from a bis-monodentate ligand featuring a non-coordinating bis-pyrazole methane backbone.

Au nanocluster adsorption and agglomeration control through sulfur modification of mesoporous TiO.

In the present work phenyl phosphine-protected Au nanoclusters were deposited onto (3-mercaptopropyl) trimethoxysilane (MPTMS) modified and unmodified mesoporous screen printed TiO. The removal of the cluster ligands by annealing was applied to enhance the interaction between Au cluster cores and semiconductor surfaces in the creation of efficient photocatalytic systems. The heat treatment could lead to undesired agglomeration of Au clusters, affecting their unique properties as size specific clusters.

Impurity profiling of methamphetamine synthesized from methyl α-acetylphenylacetate.

The group of P2P precursors including α-phenylacetoacetonitrile (APAAN), α-phenylacetoamide (APAA) and methyl α-acetylphenylacetate (MAPA) has become increasingly popular in Europe and other parts of the world in the last decade. Previous investigations have reported the use of APAAN in the synthesis of amphetamine and methamphetamine and identified a range of characteristic impurities. This research has expanded upon the current literature by investigating the use of MAPA in the synthesis of methamphetamine.

Impurity profiling of methamphetamine synthesised from α-phenylacetoacetonitrile (APAAN).

The rise in popularity of 'designer' precursor compounds for the synthesis of amphetamine-type stimulants poses a significant challenge to law enforcement agencies. One such precursor is α-phenylacetoacetonitrile (APAAN). APAAN emerged in Europe in 2010 and quickly became one of the most popular precursors for amphetamine synthesis in that region.

A Tetra-Porphyrin Host Exhibiting Interannular Cooperativity.

Recently identified as another form of cooperativity, interannular cooperativity is rarely observed in supramolecular chemistry. A tetra-porphyrin molecular tweezer with two bis-porphyrin binding sites is reported that exhibits archetypal interannular cooperativity when complexing 1,4-diazabicyclo[2.2.

Ranking Oxidant Sensitiveness: A Guide for Synthetic Utility.

Common oxidants used in chemical synthesis, including newly developed perruthenates, were evaluated in the context of understanding (and better appreciating) the sensitiveness and associated potential hazards of these reagents. Analysis using sealed cell differential scanning calorimetry (scDSC) facilitated Yoshida correlations, which were compared to impact sensitiveness and electrostatic discharge experiments (ESD), that enabled sensitiveness ranking. Methyltriphenylphoshonium perruthenate (MTP3, 8), isoamyltriphenylphosphonium perruthenate (ATP3, 7) and tetraphenylphosphonium perruthenate (TP3, 9) were found to be the most sensitive followed by 2-iodoxybenzoic acid (IBX, 2) and benzoyl peroxide (BPO, 10), whereas the most benign were observed to be Oxone (12), manganese dioxide (MnO , 13), and N-bromosuccinimide (NBS, 17).

Molecular tweezers with a rotationally restricted linker and freely rotating porphyrin moieties.

The effect of the degree of conformational rigidity and/or flexibility on preorganisation in artificial molecular receptors continues to be actively explored by supramolecular chemists. This work describes a bis-porphyrin architecture, linked via a rigid polycyclic backbone, in which a sterically bulky 2,3,5,6-tetramethylphenyl diimide core restricts rotation to afford two non-interconvertible tweezer conformations; syn- and anti-. After separation, the host-guest chemistry of each conformation was studied independently.

Detailed investigations into the Akabori-Momotani reaction for the synthesis of amphetamine type stimulants: Part 2.

The Akabori-Momotani reaction can be used to synthesise pseudoephedrine in 50% yield from N-methylalanine and benzaldehyde. This paper investigates electronic effects of substituted benzaldehydes on the reaction to synthesise amphetamine type stimulants and identifies several new Akabori-Momotani by-products, 1-[(4-methoxybenzyl)(methyl)amino]ethanol (11c), 2-(4-methoxyphenyl)-3,4-dimethyl-1,3-oxazolidine (12c), 1,2,3,4-tetramethyl-5,6-di-(4-methoxyphenyl)piperazine (13c) and 1,2,4,5-tetramethyl-3,6-di-(4-methoxyphenyl)piperazine (14c). This paper also investigates pseudoephedrine and methamphetamine isomeric distribution from the Akabori-Momotani reaction with the aid of molecular modelling to understand why more pseudoephedrine than ephedrine is produced.

Polysulfides made from re-purposed waste are sustainable materials for removing iron from water.

Water contaminated with Fe is undesirable because it can result in discoloured plumbing fixtures, clogging, and a poor taste and aesthetic profile for drinking water. At high levels, Fe can also promote the growth of unwanted bacteria, so environmental agencies and water authorities typically regulate the amount of Fe in municipal water and wastewater. Here, polysulfide sorbents-prepared from elemental sulfur and unsaturated cooking oils-are used to remove Fe contaminants from water.

Insights into the complexation of N-Allyl-4-(4-(N-phenylureido)benzylamino)-1,8-naphthalimide with various anions.

A new urea functionalised 4-amino-1,8-naphthalimide based fluorescent anion sensor was synthesised in 64% yield over three steps. Fluorescence and H NMR titrations showed that the sensor complexes strongly with acetate and dihydrogen phosphate and to a lesser extent bromide. The corresponding binding stoichiometries were examined using H NMR titrations.

The synthesis and investigation of impurities found in Clandestine Laboratories: Baeyer-Villiger Route Part I; Synthesis of P2P from benzaldehyde and methyl ethyl ketone.

The synthesis of impurities detected in clandestinely manufactured Amphetamine Type Stimulants (ATS) has emerged as more desirable than simple "fingerprint" profiling. We have been investigating the impurities formed when phenyl-2-propanone (P2P) 5, a key ATS precursor, is synthesised in three steps; an aldol condensation of benzaldehyde and methyl ethyl ketone (MEK); a Baeyer-Villiger reaction; and ester hydrolysis. We have identified and selectively synthesised several impurities that may be used as route specific markers for this series of synthetic steps.

Mass spectrometry imaging reveals new biological roles for choline esters and Tyrian purple precursors in muricid molluscs.

Despite significant advances in chemical ecology, the biodistribution, temporal changes and ecological function of most marine secondary metabolites remain unknown. One such example is the association between choline esters and Tyrian purple precursors in muricid molluscs. Mass spectrometry imaging (MSI) on nano-structured surfaces has emerged as a sophisticated platform for spatial analysis of low molecular mass metabolites in heterogeneous tissues, ideal for low abundant secondary metabolites.

SERS and NMR Studies of Typical Aggregation-Induced Emission Molecules.

Over recent decades, aggregation-induced emission (AIE) molecules have attracted increasing attention. Restriction of intramolecular rotation (RIR) has been widely accepted as the cause of the emission when AIE molecules aggregate into clusters. The intramolecular rotation of AIE molecules can be monitored by molecular vibration spectra such as nuclear magnetic resonance (NMR), infrared, and Raman, especially surface-enhanced Raman scattering (SERS) which has high sensitivity down to a single molecule.

Mechanistic insights into the luminescent sensing of organophosphorus chemical warfare agents and simulants using trivalent lanthanide complexes.

Organophosphorus chemical warfare agents (OP CWAs) are potent acetylcholinesterase inhibitors that can cause incapacitation and death within minutes of exposure, and furthermore are largely undetectable by the human senses. Fast, efficient, sensitive and selective detection of these compounds is therefore critical to minimise exposure. Traditional molecular-based sensing approaches have exploited the chemical reactivity of the OP CWAs, whereas more recently supramolecular-based approaches using non-covalent interactions have gained momentum.

Morphine glucuronidation and glucosidation represent complementary metabolic pathways that are both catalyzed by UDP-glucuronosyltransferase 2B7: kinetic, inhibition, and molecular modeling studies.

Morphine 3-β-D-glucuronide (M3G) and morphine 6-β-D-glucuronide (M6G) are the major metabolites of morphine in humans. More recently, morphine-3-β-d-glucoside (M-3-glucoside) was identified in the urine of patients treated with morphine. Kinetic and inhibition studies using human liver microsomes (HLM) and recombinant UGTs as enzyme sources along with molecular modeling were used here to characterize the relationship between morphine glucuronidation and glucosidation.

VX and VG chemical warfare agents bidentate complexation with lanthanide ions.

Investigations into V-agent interaction with 1,10-phenanthroline nitrate Ln(III) complexes (Eu and Tb) were carried out using luminescence and UV-Vis spectroscopy. Addition of several equivalents of agent resulted in the loss of luminescence intensity and the observation of free 1,10-phenanthroline by UV-Vis. We propose a displacement mechanism in which the V-agent acts as a bidentate ligand to the lanthanide ion.

Purified brominated indole derivatives from Dicathais orbita induce apoptosis and cell cycle arrest in colorectal cancer cell lines.

Dicathais orbita is a large Australian marine gastropod known to produce bioactive compounds with anticancer properties. In this research, we used bioassay guided fractionation from the egg mass extract of D. orbita using flash column chromatography and identified fractions containing tyrindoleninone and 6-bromoisatin as the most active against colon cancer cells HT29 and Caco-2.

29Si{1H} CP-MAS NMR comparison and ATR-FTIR spectroscopic analysis of the diatoms Chaetoceros muelleri and Thalassiosira pseudonana grown at different salinities.

Diatoms are key indicators of marine environmental health. To further understand how diatoms respond to varying degrees of salinity, either due to climate change or brine waste discharge into marine environments, two different diatom species were studied. Thalassiosira pseudonana and Chaetoceros muelleri were cultured at three different salinities namely, 26 practical salinity units (PSU or parts per thousand), 36 PSU (standard salinity for culturing of seawater species) and 46 PSU.

Synthesis, structure, and biological applications of α-fluorinated β-amino acids and derivatives.

This review gives a broad overview of the state of play with respect to the synthesis, conformational properties, and biological activity of α-fluorinated β-amino acids and derivatives. General methods are described for the preparation of monosubstituted α-fluoro-β-amino acids (Scheme 1). Nucleophilic methods for the introduction of fluorine predominantly involve the reaction of DAST with alcohols derived from α-amino acids, whereas electrophilic sources of fluorine such as NFSI have been used in conjunction with Arndt-Eistert homologation, conjugate addition or organocatalyzed Mannich reactions.

Analysis of the hydrolysis of inulin using real time 1H NMR spectroscopy.

The hydrolysis of various carbohydrates was investigated under acidic conditions in real time by (1)H NMR spectroscopy, with a focus on the polysaccharide inulin. Sucrose was used as a model compound to illustrate the applicability of this technique. The hydrolysis of sucrose was shown to follow pseudo first order kinetics and have an activation energy of 107.

Observation of the keto tautomer of D-fructose in D(2)O using (1)H NMR spectroscopy.

D-Fructose was analysed by NMR spectroscopy and previously unidentified (1)H NMR resonances were assigned to the keto and α-pyranose tautomers. The full assignment of shifts for the various fructose tautomers enabled the use of (1)H NMR spectroscopy in studies of the mutarotation (5-25°C) and tautomeric composition at equilibrium (5-50°C). The mutarotation of β-pyranose to furanose tautomers in D(2)O at a concentration of 0.

Diastereoselective synthesis of aliphatic α,α-difluoro-β3-amino esters via a sonocatalyzed Reformatsky reaction.

(R)-2-Phenylglycine ethyl ester was found to be a cheap and effective auxiliary for the preparation of aliphatic α,α-difluoro-β(3)-amino esters via a Reformatsky reaction performed under sonication conditions. The products were obtained in good to high yield and ≥96:4 dr, thus providing a new stereoselective route to this under-represented class of compounds. A facile one-pot removal of the phenylglycine moiety and concomitant Boc protection subsequently afforded the corresponding Boc-protected β(3)-amino esters in excellent yield.

Chemical analysis of four capsules containing the controlled substance analogues 4-methylmethcathinone, 2-fluoromethamphetamine, alpha-phthalimidopropiophenone and N-ethylcathinone.

In August 2007, four capsules containing white powders, said to have originated from an Israel-based Internet company "Neorganics", were anonymously delivered to the Royal Adelaide Hospital, South Australia. The capsules were analysed and the active components were identified including 4-methylmethcathinone, 2-fluoromethamphetamine, alpha-phthalimidopropiophenone and N-ethylcathinone, all of which were unlisted within South Australian controlled substance regulations. We examined the relevant scientific literature surrounding these chemicals and present both GCMS and NMR data for 4-methylmethcathinone and alpha-phthalimidopropiophenone, which have previously received little attention.

The synthesis and characterisation of a free-base porphyrin-perylene dyad that exhibits electronic coupling in both the ground and excited states.

A covalent dyad composed of a free-base porphyrin and a perylene diimide (1) was synthesised and characterised by NMR, HRMS, UV/Vis and fluorometric methods. UV/Vis spectrophotometric analysis indicated a moderate coupling between the components in the ground state. Fluorescence spectroscopy revealed that the emissive properties of the dyad showed that the quantum yield of emission from the porphyrin Soret band increased dramatically and could not be rationalised by a straightforward photoinduced energy (and/or electron) transfer, but rather a coupling of excited states.