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The article "Pyrene-Phosphonate Conjugate: Aggregation-Induced Enhanced Emission, and Selective Fe3+ Ions Sensing Properties" published in Molecules in 2017 has been retracted due to concerns raised by the Royal Melbourne Institute of Technology (RMIT) regarding an image and the validity of the findings. An investigation conducted by the Editorial Board and Editorial Office, including input from RMIT, found overlapping elements in Figure 1 and a lack of raw material to verify the presented findings. As a result, the article was retracted in accordance with MDPI's retraction policy and the Committee on Publication Ethics guidelines. The authors agreed to the retraction, while others did not provide a comment on the decision. [Extracted from the article]

Design, synthesis and characterization of novel (2S)‐2‐[7‐(2‐aminoethyl)‐1,3,6,8‐tetraoxo‐3,6,7,8‐tetrahydrobenzo[lmn][3,8]phenanthrolin‐2(1H)‐yl]propanoic acid (1) bolaamphiphile, which combine naphthalene diimide (NDI) appended with l‐alanine at one end of imide and ethylenediamine at the other end. An l‐alanine bearing NDI‐based asymmetric bolaamphiphile self‐assembled at various pH ranging from 2 to 10 forms a variety of supramolecular nanostructures. The UV‐Vis and emission spectroscopic techniques employed for the optical and photophysical properties study of bolaamphiphile 1 at various pH values. It was revealed that the change in pH alters both the optical and photophysical properties of bolaamphiphile 1. Theoretical calculations used to investigate the electronic properties of the bolaamphiphile 1. Dynamic light scattering experiments displayed formation of aggregates in solution and scanning electron microscopy (SEM) was used to visualize the nanostructures formed on silicon wafers. Furthermore, the X‐ray diffraction was used to determine the nanostructure's packing properties i. e. crystalline/amorphous. Experimental circular dichroism (CD) spectroscopy results inferred and revealed the induction of chirality into the supramolecular systems, which was shown to be pH dependent. This study clearly demonstrates the manipulation of pH can control/tune chiral supramolecular structures and provide future methods for the development of chiral recognition and catalysis study. [ABSTRACT FROM AUTHOR]

Herein, the synthesis and supramolecular self‐assembly of naphthalenediimide (NDI)‐tetraphenylethene (TPE) conjugates with l‐alanine (coded as: 1) and d‐alanine (coded as: 2) was investigated. The pair stereoisomer molecules were designed to undergo self‐assembly under solvophobic effects. Mixtures of THF–water was used to fine tune the solvophobic effect leading to microbelt for both 1 and 2 in 40% v/v of THF in H2O, while microbelt and particulate microsphere supramolecular structures were observed in 20%, v/v THF in H2O. When 10% THF in H2O was employed derivative 1 produces belt‐like structures, however, 2 produces microsphere. Less uniformly defined microstructure morphologies of 1 and 2 were formed in THF/hexane and DCM/hexane. The solvophobic effect on self‐assembly further evidenced using UV/Vis, fluorescence, circular dichroism, X‐ray diffraction (XRD) spectroscopies. DLS used to evaluate formation of assembly in solution, DFT (density functional theory) and TD‐DFT (time dependent density functional theory) molecular modelling support the hypothesis. Scanning electron microscopy used to visualise formation of supramolecular self‐assembled nano‐ and micro‐structures. Supramolecular self‐assembly behaviour of naphthalenediimide (NDI)‐ tetraphenylethene (TPE) conjugates with l‐ (1) and d‐alanine spacer (2) was investigated. The molecules were designed to undergo self‐assembly under solvophobic effects leading to various structures such as microbelt, fibrils, microsphere etc. depending on solvent proportion of THF/H2O, THF/hexane and DCM/hexane. Even NDI bearing TPE moieties showing ACQ effect rather than AIE due to photoinduced charge transfer between TPE donor and NDI acceptor. [ABSTRACT FROM AUTHOR]

A new pyrene-phosphonate colorimetric receptor 1 has been designed and synthesized in a one-step process via amide bond formation between pyrene butyric acid chloride and phosphonate-appended aniline. The pyrene-phosphonate receptor 1 showed aggregation-induced enhanced emission (AIEE) properties in water/acetonitrile (ACN) solutions. Dynamic light scattering (DLS) characterization revealed that the aggregates of receptor 1 at 80% water fraction have an average size of ≈142 nm. Field emission scanning electron microscopy (FE-SEM) analysis confirmed the formation of spherical aggregates upon solvent evaporation. The sensing properties of receptor 1 were investigated by UV-vis, fluorescence emission spectroscopy, and other optical methods. Among the tested metal ions, receptor 1 is capable of recognizing the Fe3+ ion selectively. The changes in spectral measurements were explained on the basis of complex formation. The composition of receptor 1 and Fe3+ ions was determined by using Job's plot and found to be 1:1. The receptor 1--Fe3+ complex showed a reversible UV-vis response in the presence of EDTA. [ABSTRACT FROM AUTHOR]

The one-step three-component microwave assisted synthesis between aromatic aldehydes with tetronic acid or indan-1,3-dione readily formed the Knoevenagel adducts that underwent addition of 3-methylisoxazol-5-amine 1 to form the isoxazolo[5,4- b ]pyridine products 8 [ a , b , d , e , g ] in 67–90% yield. The multicomponent reaction using dimedone formed the respective addition products 4-aryl-3,7,7-trimethyl-isoxazolo[5,4- b ]quinolin-5(6 H )-ones 8 [ c , f , h ] (36–79%). In contrast, the sonication of an aryl aldehyde and dimedone with an equivalent amount of 2-hydroxyammonium formate exclusively generated the Knoevenagel adduct 4c via hydro - 4c . When microwaved either with 3-amino-5-methylisoxazole 1 or 3,4,5-trimethoxyaniline 14 in ethanoic acid–ethylacetate (1:1), tetrahydroacridones 15 [ a , b ] formed in high yields (88–92%). Importantly, this two-step reaction sequence generates highly reproducible and pure products. [ABSTRACT FROM AUTHOR]

Abstract: Uranium bearing ores are often a complex mixture of minerals and compounds, a number of which are not of economic importance and are commonly referred to as gangue materials. In order to improve the efficiency of the dissolution stage of the overall uranium extraction process, a greater understanding of the minerals and compounds present in the ore is required. A greater knowledge of the gangue materials present is important as they can influence various aspects of the dissolution process such as providing potential adsorption sites for aqueous uranium species and through influencing the equilibrium of reactions involving aqueous uranium species. In this study the mineralogy of a uranium ore was investigated using a range of X-ray diffraction (XRD) based methods including in situ high temperature XRD and XRD using a synchrotron beam line. The results obtained from standard XRD (Cu Kα), high temperature XRD and synchrotron XRD (16.534keV) were compared and a number of minerals were identified. The improved spatial resolution and intensity of the synchrotron data allowed for superior phase identification of a variety of minerals where standard X-ray techniques gave inconclusive results. [Copyright &y& Elsevier]