Showing papers in "New Journal of Chemistry in 2010"
TL;DR: In this paper, a review of metal-organic frameworks (MOFs) and porous coordination polymers (PCPs) with selected examples of their structures, concepts for linkers, syntheses, post-synthesis modifications, metal nanoparticle formations in MOFs, porosity and zeolitic behavior for applications in gas storage for hydrogen, carbon dioxide, methane and applications in conductivity, luminescence and catalysis.
Abstract: This review (over 380 references) summarizes metal–organic frameworks (MOFs), Materials Institute Lavoisier (MILs), iso-reticular metal–organic frameworks (IR-MOFs), porous coordination networks (PCNs), zeolitic metal–organic frameworks (ZMOFs) and porous coordination polymers (PCPs) with selected examples of their structures, concepts for linkers, syntheses, post-synthesis modifications, metal nanoparticle formations in MOFs, porosity and zeolitic behavior for applications in gas storage for hydrogen, carbon dioxide, methane and applications in conductivity, luminescence and catalysis.
1,017 citations
TL;DR: In this paper, the authors used Hirshfeld surface analysis to reveal that more than two-thirds of the close contacts are associated with relatively weak H⋯H, C⋻H, and H ⋯C interactions.
Abstract: Hydroquinone (benzene-1,4-diol or quinol) is reported here to form co-crystals in different ratios with propan-2-ol, N,N-dimethylacetamide (DMA) and N,N-diethylformamide (DEF). Investigation of intermolecular interactions and crystal packing via Hirshfeld surface analysis reveals that more than two-thirds of the close contacts are associated with relatively weak H⋯H, C⋯H and H⋯C interactions. The use of Hirshfeld surfaces in combination with fingerprint plots demonstrates that these weak interactions are important for both local packing and crystal packing. The complexes highlight the way in which electrostatic complementarity to a large extent governs the hydrogen bonding pattern in molecular crystals.
274 citations
TL;DR: The state-of-the-art as well as the contribution of the group to the field of reactive and catalytic supramolecular gels are described.
Abstract: Supramolecular gels have attracted an enormous amount of interest from scientists in the last decade because of their potential applications proposed up to now in fields of great social impact like biomedicine or materials science. However, their potential in organic transformations and catalysis has been only scarcely explored. In this review we describe the state-of-the-art as well as the contribution of our group to the field of reactive and catalytic supramolecular gels.
248 citations
TL;DR: In this article, the authors used pulse current deposition to prepare evenly distributed and uniformly sized Ag nanoparticles on a TiO2 nanotube array photoelectrode, and the resulting electrode contained intimately coupled, three-dimensional Ag/TiO2 structures with greatly improved photocurrent generation and charge transfer compared to a two-dimensional random Ag particle layer.
Abstract: In the current work, pulse current deposition has been used to prepare evenly distributed and uniformly sized Ag nanoparticles on a TiO2 nanotube array photoelectrode. The Ag particle size and loading were controlled by the pulse deposition time. The Ag/TiO2 nanotube arrays were characterized by SEM, TEM, XRD, XPS and UV-vis diffuse reflection absorption. The resulting electrode contained intimately coupled, three-dimensional Ag/TiO2 structures with greatly improved photocurrent generation and charge transfer compared to a two-dimensional random Ag particle layer deposited directly on top of the nanotube array by the regular photoinduction method. A model mechanism is proposed to illustrate the uniform Ag nanoparticle deposition via the new deposition technique developed in the current work that promotes the uniform distribution of the Ag particles whilst minimizing their deposition at tube entrances, thus effectively preventing the pores from becoming clogged.
176 citations
TL;DR: In this paper, a one-pot solvothermal reaction was used to prepare graphene/Fe3O4 composites using graphite oxide and FeCl3·6H2O as starting materials.
Abstract: A one-pot solvothermal reaction was used to prepare graphene/Fe3O4 composites using graphite oxide and FeCl3·6H2O as starting materials. Graphene oxide was reduced to graphene and the Fe3O4 microspheres were simultaneously grown on the carbon basal planes under the conditions generated in the solvothermal system. The product showed a high crystallinity of magnetite and a considerable saturation magnetization. The size and density of the Fe3O4 microspheres distributed on the graphene can be easily controlled by altering the starting Fe3+ concentration. Doxorubicin hydrochloride was loaded on to the graphene/Fe3O4 composites by simple mixing, and a saturation loading capacity as high as 65% could be achieved.
174 citations
TL;DR: High yields of hydrophilic carbon nanoparticles (CNPs) were prepared by the controlled carbonization of sucrose and after surface functionalisation with PEG2000N, the non-luminous CNPs successfully emitted a blue fluorescence.
Abstract: High yields of hydrophilic carbon nanoparticles (CNPs) were prepared by the controlled carbonization of sucrose. Green luminescent CNPs and non-luminous CNPs were effectively separated by dialysis. After surface functionalisation with PEG2000N, the non-luminous CNPs successfully emitted a blue fluorescence.
170 citations
TL;DR: The chemistry of 1,3-dialkylimidazolium-based ionic liquids (ILs) can easily be linked to that of N-heterocyclic carbenes (NHCs) in the presence of sufficiently basic counteranions as discussed by the authors.
Abstract: The chemistry of 1,3-dialkylimidazolium-based ionic liquids (ILs) can easily be linked to that of N-heterocyclic carbenes (NHCs) in the presence of sufficiently basic counteranions. B3LYP/6-31+G*, B3LYP/aug-cc-pVTZ and MP2/6-311+G** studies show that increasing the basicity of the anionic component the relative stability of the ion pair and that of the hydrogen bonded complex of the corresponding free acid and NHC itself can be shifted toward the formation of NHC. In the case of the acetate anion, the ion pair and the NHC-acetic acid complex have similar stability. Photoelectron spectroscopic studies show that the vapor of EMIM-acetate is dominated by the NHC-acetic acid complex. The mass spectrum of the same compound shows the presence of both acetic acid and 1-ethyl-3-methylimidazolium-2-ylidene, in agreement with the low pressure during the MS experiment, which facilitates dissociation. The possibility of systematic and simple variation of the NHC content of the ILs facilitates the extension of carbene chemistry in ionic liquids.
163 citations
TL;DR: Examples of calixarene macrocycles spanning the recognition of small peptides and carbohydrates to ion transport through membranes, biomimetic catalysis, DNA condensation and cell transfection, protein binding, sensing and inhibition are illustrated.
Abstract: Calixarenes are versatile platforms for the design and synthesis of molecular receptors and multivalent ligands that are able to mimic or affect specific biological functions. This review illustrates examples spanning the recognition of small peptides and carbohydrates to ion transport through membranes, biomimetic catalysis, DNA condensation and cell transfection, protein binding, sensing and inhibition, and gives perspectives for using calixarene macrocycles in bio-supramolecular chemistry.
146 citations
TL;DR: In this paper, the influence of both cation and anion structure on π*, α, β, and π* values of 38 1-alkyl-3-methylimidazolium ILs ([Rmim]X) are presented in order to give a solid background for the discussion.
Abstract: Based on the developed tool to measure Kamlet–Taft polarity parameters α (hydrogen bond donating ability), β (hydrogen bond accepting ability), and π* (dipolarity/polarisability) for ionic liquids (ILs), it is now possible to precisely determine the influence of both cation and anion structure on π*. α, β, and π* values of 38 1-alkyl-3-methylimidazolium ILs ([Rmim]X) are presented in this work to give a solid background for the discussion. The dipolarity/polarisability of [Rmim]X determined by means of the established π*-sensitive solvatochromic probe 4-tert-butyl-2-(dicyanomethylene)-5-[4-(diethylamino)benzylidene]-Δ3-thiazoline is a blend of dipolarity and polarisability in equal parts. The large π* parameters of ionic liquids are attributed to two cumulative effects: the ion pairing strength and the individual polarisabilities of both the cation and anion. This is shown by the influence of anion and cation structures (alkyl chain length of R) on the dipolarity/polarisability. For all studied ionic liquids we observed a general trend. The stronger the ion pairing effect, the greater is the determined π* value.
134 citations
TL;DR: A brief survey of the properties of oxyacids and their esters for other candidate elements for these vital roles fails to identify a suitable alternative to phosphorus, thereby underpinning Todd's Hypothesis “Where there’s life there‘s phosphorus” as a statement of truly universal validity.
Abstract: Evolution has placed phosphate mono- and diesters at the heart of biology. The enormous diversity of their roles has called for the evolution of enzyme catalysts for phosphoryl transfer that are among the most proficient known. A combination of high-resolution X-ray structure analysis and 19F NMR definition of metal fluoride complexes of such enzymes, that are mimics of the transition state for the reactions catalysed, has delivered atomic detail of the nature of such catalysis for a range of phosphoryl transfer processes. The catalytic simplicity thus revealed largely explains the paradox of the contrast between the extreme stability of structural phosphate esters and the lability of phosphates in regulation and signalling processes. A brief survey of the properties of oxyacids and their esters for other candidate elements for these vital roles fails to identify a suitable alternative to phosphorus, thereby underpinning Todd’s Hypothesis “Where there’s life there’s phosphorus” as a statement of truly universal validity.
131 citations
TL;DR: In this paper, the authors demonstrate that through weak intermolecular forces, such as π/π, van der Waals and CH/π interactions, CD-/CPL-active F8T2 aggregates successfully emerge in a chiral tersolvent system of chloroform (a good solvent), alkanol (a poor solvent), and limonene (a chiral solvent), which greatly affects the magnitude and sign of the induced CD signals.
Abstract: Solvent chirality transfer using (S)- and (R)-limonenes, which are candidates for renewable volatile bioresources (bp 176 °C/760 Torr or bp 94 °C/68 Torr), allowed for the successful production of optically active poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-bithiophene] (F8T2) particles with circular dichroism (CD) and circularly polarised luminescence (CPL) properties. The particles were rapidly produced by CD-silent F8T2 with the aid of solvent chirality transfer at 25 °C. The present paper demonstrates the following: (i) through weak intermolecular forces, such as π/π, van der Waals and CH/π interactions, CD-/CPL-active F8T2 aggregates successfully emerge in a chiral tersolvent system of chloroform (a good solvent), alkanol (a poor solvent) and limonene (a chiral solvent); (ii) the alkanol and the enantiopurity of the limonene greatly affect the magnitude and sign of CD-/CPL-signals; (iii) aggregate size considerably affects the magnitude of the induced CD amplitude; (iv) clockwise and counter-clockwise stirring during preparation do not affect the magnitude of these signals; (v) stirring speed weakly affects the induced CD amplitude and (vi) the order of addition of limonene and methanol to the chloroform solution of F8T2 greatly affects the magnitude of the induced CD amplitude. To prove the renewability of limonenes, we re-used (S)-limonene purified by distilling very impure (S)-limonene-containing chloroform, methanol and F8T2, which was used and stored in a number of limonene chirality transfer experiments. As expected, the CD-/UV-vis spectra of F8T2 particles utilizing the renewed (S)-limonene gave similar CD-/UV-vis spectra to those using the fresh (S)-limonene. Moreover, limonene chirality transfer was possible to obtain two CD-active polymers from CD-silent, poly(9,9-di-n-octylfluorenyl-2,7-diyl) (F8) and poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-thiophene] (F8T1). The protocol may provide an environmentally friendly, safe and mild process to rapidly produce ambidextrous light-emitting polymers with a minimal loss of starting polymers at ambient temperature, from CD-silent polymers without any specific chiral substituents or chiral catalysts.
TL;DR: In this paper, a mesoporous hybrid material (Py-SBA-15) for detecting Hg2+ ions in water was prepared through the functionalization of mesoporous silica (SBA15) with a modified fluorescent chromophore, 1-(4′-hydroxyphenyl)-4-pyrenyl-2,3-diaza-1, 3-butadiene (py-OH), covalently grafted to the coupling agent 3-(triethoxysilyl)propylisocyanate (
Abstract: A novel fluorescent chemosensing hybrid material (Py-SBA-15) for detecting Hg2+ ions in water was prepared through the functionalization of mesoporous silica (SBA-15) with a modified fluorescent chromophore, 1-(4′-hydroxyphenyl)-4-pyrenyl-2,3-diaza-1,3-butadiene (Py-OH). Py-OH covalently grafted to the coupling agent 3-(triethoxysilyl)propylisocyanate (TESPIC) was used as the precursor for the preparation of mesoporous hybrid material. The XRD data and TEM images of Py-SBA-15 confirm that the hexagonal ordered mesoporous structure is preserved after functionalization. Py-SBA-15 demonstrates a high selectivity for Hg2+ ions in the presence of other metal ions, which results from a dramatic fluorescence enhancement by the addition of Hg2+ ions upon the suspensions of Py-SBA-15. A good linearity (R2 = 0.9989) between the fluorescence intensity of Py-SBA-15 and the concentration of Hg2+ ions is constructed, and a satisfactory detection limit of 1.7 × 10−7 g mL−1 is obtained. More importantly, Py-SBA-15 shows good regenerative ability due to the greatly minimized leaching effect of the sensing molecules by covalent grafting strategy. These results presented in this paper indicate that this hybrid material could be a promising fluorescence chemosensor for detecting Hg2+ ions.
TL;DR: An iterative method using commercial software that allows for the rigorous determination of binding constants in a variety of systems, including 1 : 2 complexes, indicator displacement assays, and enantioselective indicator displacementAssays, allowing for a more precise determination of ee in competitive equilibria.
Abstract: The determination of binding constants is central to many areas of research, supramolecular chemistry in particular. Traditional nonlinear regression analysis, however, cannot be applied to complex systems unless certain assumptions are undertaken, which often limits the reliability of such calculations. Our group has developed an iterative method using commercial software that allows for the rigorous determination of binding constants in a variety of systems, including 1 : 2 complexes, indicator displacement assays, and enantioselective indicator displacement assays. The improved accuracy of the values obtained in the latter case, in turn, allows for a more precise determination of ee in competitive equilibria.
TL;DR: A series of pyridyl-appended bis(urea) ligands form supramolecular gels in the presence of metal ions (metallogels), particularly copper(II) and silver(I).
Abstract: A series of pyridyl-appended bis(urea) ligands form supramolecular gels in the presence of metal ions (metallogels), particularly copper(II) and silver(I). The gels have been characterised by rheometry and SEM, and the effect of the metal ions on gel strength and morphology examined. The metal-induced gelation is linked to the competition between urea–urea and urea–pyridyl hydrogen bonding interactions. Crystals grown from these gels reveal a wealth of structural information about these systems that can be related to gel structure using powder X-ray diffraction data of their xerogels.
TL;DR: In vivo biological properties of phosphorus-containing dendrimers as anti-prion agents, for ocular drug delivery, and for imaging rat brain blood vessels are described.
Abstract: This review will display the special role played by phosphorus-containing dendrimers when interacting with biological systems. After some synthetic aspects, the usefulness of these dendrimers for elaboration of highly sensitive bio-sensors and for in vitro drug delivery (for instance as transfection agents, or against HIV-1 and the scrapie form of prions) will be demonstrated. Then, emphasis will be put on the favourable influence of these dendrimers on cells growth, in particular for neuronal cells, and for human immune blood cells such as monocytes and Natural Killer cells, the latter playing a key-role for fighting against viral infections and cancers. This review will finally describe in vivo biological properties of these phosphorus dendrimers as anti-prion agents, for ocular drug delivery, and for imaging rat brain blood vessels. Some of these properties can be found also with other types of dendrimers, but others, in particular the interaction with the human immune blood cells, occur only and specifically with phosphorus dendrimers.
TL;DR: When tested for their cytotoxicity and genotoxicity on HepG2 cells, glycolipid nanoparticle conjugates are found to be cytocompatible up to 100 μM metal concentrations, and it is demonstrated that at 100μM, silver nanoparticles cause more DNA damage compared to gold nanoparticles of similar concentrations.
Abstract: A systematic cytotoxic and genotoxic evaluation of glycolipid-conjugated silver and gold nanoparticles is carried out. These glycolipid nanoparticle conjugates are obtained by exploiting the reductive capability of a class of glycolipids called sophorolipids that play the role of capping agent as well. Further, when tested for their cytotoxicity and genotoxicity on HepG2 cells, these nanoparticles are found to be cytocompatible up to 100 μM metal concentrations. Of the two metallic systems investigated, gold nanoparticles are found to be more cytocompatible than the same concentrations of silver nanoparticles. Similarly, it is also demonstrated that at 100 μM, silver nanoparticles cause more DNA damage compared to gold nanoparticles of similar concentrations.
TL;DR: A short review of the chemistry of amphiphilic calixarenes and resorcinarenes with a clear focus on the synthetic paths used for their production and their self-assembly properties in water is given in this article.
Abstract: The calixarenes and resorcinarenes are macrocyclic phenolic molecules that can be modified “a facon” and a wide range of chemical modification strategies have been published over the last 30 years. Because of their remarkable structural properties and their relative ease of chemical modification, they represent excellent and highly versatile bases to design complex building blocks capable of self-assembly and molecular recognition. They have been widely studied for their ability to form supramolecular structures targeting a wide range of applications. The possibility to regio(rim)-selectively modify these macrocycles with different polar and apolar moieties provides synthetic chemists with an unlimited range of possibilities for the design of complex amphiphiles with a high control over the position of the grafted moieties in the three dimensions. These amphiphiles have been shown to possess outstanding self-assembling and/or molecular recognition properties. This short review describes the developments of the chemistry of amphiphilic calixarenes and resorcinarenes with a clear focus on the synthetic paths used for their production and their self-assembly properties in water.
TL;DR: In this article, an oxidatively stabilized electrospun poly(acrylonitrile) fiber was used for the preparation of ultrafine carbon fiber webs, followed by carbonization or by further activation with steam.
Abstract: Ultrafine carbon fiber webs were prepared from oxidatively stabilized electrospun poly(acrylonitrile) fibers, followed by carbonization or by further activation with steam. Capacitive de-ionization was evaluated in the batch mode. It was found that the webs exhibited considerable electrical adsorption, which was enhanced by activation with a faster electrosorption rate and a higher electrosorption capacity.
TL;DR: Merocyanine dye 1 was prepared as an effective colorimetric and fluorescent chemosensor for copper ions in aqueous media, and displays a significant color change from reddish-purple to yellow with a large blue shift of 94 nm in its absorption spectrum in the presence of one equivalent of copper.
Abstract: Merocyanine dye 1 was prepared as an effective colorimetric and fluorescent chemosensor for copper ions in aqueous media, and displays a significant color change from reddish-purple to yellow with a large blue shift of 94 nm in its absorption spectrum in the presence of one equivalent of copper. As an on–off fluorescent sensor, it is feasible to detect copper ions in living cells due to its good cell permeability and high solubility under physiological conditions.
TL;DR: In this article, a reaction scheme was devised according to 3 RX + 3 Ti(III) + 0.25 P4 → PR3 + 3 XTi(IV), wherein RX = PhBr, CyBr, Me3SiI or Ph3SnCl, with contrasting results in the case of more hindered RX.
Abstract: A reaction scheme has been devised according to 3 RX + 3 Ti(III) + 0.25 P4 → PR3 + 3 XTi(IV), wherein RX = PhBr, CyBr, Me3SiI or Ph3SnCl, with contrasting results in the case of more hindered RX. The scheme accomplishes the direct radical functionalization of white phosphorus without the intermediacy of PCl3.
TL;DR: In this article, an equation for the transfer of neutral solutes from water to the solvents ethylene glycol and propylene carbonate has been constructed, and the equations have been extended to include ions and ionic species derived from acids by loss of a proton and bases by acceptance of a Proton.
Abstract: Equations have been constructed for the transfer of neutral solutes from water to the solvents ethylene glycol and propylene carbonate. These equations have been extended to include ions and ionic species derived from acids by loss of a proton and bases by acceptance of a proton. Only one additional term is needed for cations and one additional term for anions. The data used include literature data on the partition coefficients of simple ions, and literature data on pKa values for carboxylic acids and amines in water, ethylene glycol and propylene carbonate from which we derive ionic partition coefficients. Descriptors have been obtained for 22 substituted pyridinium cations, and equations derived for the prediction of descriptors for further substituted pyridinium cations. Some of the pyridinium cations are the strongest hydrogen bond acids that we have encountered.
TL;DR: Biocompatibility of the developed nanocarriers was evaluated in vitro by assessing their cytotoxicity on human cervical cancer cells using a sulforhodamine B (SRB) assay and the change in surface charge strongly suggests the interaction of DOX with the DMNCs.
Abstract: A novel arginine-based dendritic block is grown on the surface of APTS-coated Fe3O4 nanoparticles by conventional growth approach of Michael addition/amidation reactions. The thus-obtained dendritic magnetite nanocarriers (DMNCs) were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), atomic force microscopy (AFM), vibrating sample magnetometry(VSM), dynamic light scattering (DLS) and thermogravimetric (TGA) analysis. The functionalization of MNPs with the dendritic block was evident from FTIR and TGA analyses. The nanocarriers had an average size of 10 nm and exhibited superparamagnetism with high magnetization values at room temperature. The aqueous colloidal suspension of DMNCs (10 mg ml−1 of Fe) showed a temperature rise up to 43 °C in 5 min and yielded a moderate specific absorption rate (SAR) value of 30 W g−1 of magnetite under the influence of AC magnetic field of 10 kA m−1 and 425 kHz frequency. Biocompatibility of the developed nanocarriers was evaluated in vitro by assessing their cytotoxicity on human cervical cancer cells (HeLA cells) using a sulforhodamine B (SRB) assay. Encapsulation and release of the anticancer drug doxorubicin (DOX) was investigated. The change in surface charge, as evident from zeta potential analyzer and quenching of fluorescence intensity, strongly suggests the interaction of DOX with the DMNCs. The nanocarriers showed good capacity to encapsulate DOX, with loading as high as 65% (w/w) and a pH-responsive sustained release of 54% at pH 5.0. Also, the release of DOX from the nanocarriers increased up to 80% on application of an AC magnetic field.
TL;DR: Recent developments in the synthesis of cap analogs modified within 5′,5′-triphosphate bridges and their utility for interdisciplinary studies on cap-dependent processes in gene expression and its regulation, as well as biotechnological applications and perspectives in medicine are presented.
Abstract: The cap structure was discovered at the 5′-end of the eukaryotic mRNA over three and a half decades ago. Since then, hundreds of chemically modified cap analogs have been synthesized and applied in numerous studies on the elucidation of cap-related physiological processes in the cell, and became important members of the biophosphate family. In this Perspective, we present recent developments in the synthesis of cap analogs modified within 5′,5′-triphosphate bridges and their utility for interdisciplinary studies on cap-dependent processes in gene expression and its regulation, as well as biotechnological applications and perspectives in medicine.
TL;DR: In this paper, the reduction potential of a dopant relative to the redox potential of SWCNTs was calculated based on theoretical calculations, which were in good agreement with the experimental data obtained from individually separated SWCNNs, and the change in the electronic structures of the carbon nanotubes with the various dopants was clearly observed by absorption and Raman spectroscopy.
Abstract: The chemical doping of single-walled carbon nanotubes (SWCNTs) has been an important issue in tailoring the electronic structures of SWCNTs. This paper proposes a strategy for controlling the doping types and doping concentrations by choosing the reduction potential of a dopant relative to the redox potential of SWCNTs. For this purpose, the redox potential plot in terms of the chirality and diameter was generated based on theoretical calculations, which were in good agreement with the experimental data obtained from individually separated SWCNTs. The change in the electronic structures of the SWCNTs with the various dopants was clearly observed by absorption and Raman spectroscopy, and was explained well by the redox potential argument. This principle was tested further by fabricating transparent conducting films followed by doping. Doping with Au3+ resulted in a sheet resistance of 100 Ω sq−1 at 90% transmittance. This SWCNT doping strategy for both n-type and p-type materials can be generalized to a wide range of nanostructures, such as nanowires and nanoparticles.
TL;DR: In this article, a simple and straightforward route for the synthesis of thioethers, thioesters, vinyl thio ethers and thio-Michael adducts has been demonstrated using silica nanoparticles (NPs) as a reusable catalyst via the 1,2-addition of thiols to alkenes, alkynes and alkyl/acyl halides.
Abstract: A simple and straightforward route for the synthesis of thioethers, thioesters, vinyl thioethers and thio-Michael adducts has been demonstrated using silica nanoparticles (NPs) as a reusable catalyst via the 1,2-addition of thiols to alkenes, alkynes and alkyl/acyl halides, and the 1,4-addition of thiols to conjugated alkenes at room temperature.
TL;DR: In this article, a series of ionic liquids bearing nucleophilic (Me2N) and non-nucleophilic base (iPr2N)-functionalities is described.
Abstract: A simple and efficient synthesis of a novel series of ionic liquids bearing nucleophilic (Me2N) and non-nucleophilic base (iPr2N) functionalities is described. The non-nucleophilic base functionality resembles the structure of the Hunig's base (N,N-diisopropylethylamine), which has been used widely in organic synthesis. A qualitative measure of the basicity of these ionic liquids is presented by utilising their interaction with universal indicator. The basicity of these ionic liquids was found to be dependent on the amine tether and choice of linker between the two nitrogen centres. The relative base strength of these ionic liquids was also probed by using them as catalysts in the Heck and Knoevenagel reactions.
TL;DR: In this article, a fast and economical route based on microwave assisted hydrothermal reaction has been developed to synthesize pancake-like Fe2(MoO4)3 microstructures.
Abstract: A fast and economical route based on microwave-assisted hydrothermal reaction has been developed to synthesize pancake-like Fe2(MoO4)3 microstructures. The phase and morphology of the products have been characterized by powder X-ray diffraction (XRD), energy dispersive spectrometry (EDS), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). Several factors, including the amount of nitric acid, reaction time, temperature and iron source, play crucial roles in the formation of the Fe2(MoO4)3 multilayer stacked structures. Detailed studies indicate that the oriented attachment and layer-by-layer self-assembly of nanosheets is responsible for the formation of these structures. The magnetic and photocatalytic properties of the product have also been investigated.
TL;DR: In this article, a composite methodology using laser ablation followed by a solution refluxing process was demonstrated to prepare GaOOH and (β-, γ-) Ga2O3 nanowires, where the CTAB surfactant and PVP polymer played different roles in selectively controlling the growth rates of different facets.
Abstract: A composite methodology using laser ablation followed by a solution refluxing process was demonstrated to prepare GaOOH and (β-, γ-) Ga2O3 nanowires, where GaOOH and γ-Ga2O3 nanowires were prepared for the first time. The CTAB surfactant and PVP polymer facilitated the nucleation and growth of GaOOH nanorods, and played different roles in selectively controlling the growth rates of different facets. In the PVA/CTAB-assisted reaction, a high aspect ratio (of at least 200) of GaOOH nanowires was approached. The calcination of GaOOH nanowires at a temperature of 500 °C (6 h) transformed them into γ-Ga2O3 nanowires and converted them further into β-Ga2O3 nanowires at 750 °C (18 h). Photoluminescence measurements were conducted at room temperature for the GaOOH and (β-, γ-) Ga2O3 nanowires using a high resolution synchrotron X-ray source. The blue emissions from the GaOOH and (β-, γ-) Ga2O3 nanowires were resolved into a few sharp peaks, and may provide a valuable reference for further understanding the PL mechanisms. Although luminescence spectra of the GaOOH and γ-Ga2O3 nanowires were recorded for the first time, the similar optical band gap and emission contour observed for β-Ga2O3 nanowires suggests that the optical behavior of GaOOH and γ-Ga2O3 nanowires are likely to closely follow the PL mechanisms of β-Ga2O3 nanowires.
TL;DR: In this paper, a mixture of 1-hydroxyethylidene-1,1-diphosphonic acid as an organophosphorus coupling molecule was used to synthesize inorganic-organic hybrid titanium phosphonate materials with a hierarchically-porous structure.
Abstract: Inorganic–organic hybrid titanium phosphonate materials with a hierarchically-porous structure were synthesized by a mild solvent evaporation strategy using 1-hydroxyethylidene-1,1-diphosphonic acid as an organophosphorus coupling molecule. The preparations were accomplished with the use of triblock copolymers F127 and P123 as structure-directing agents. All the samples possessed a macroporous morphology of the mesoporous framework with a high surface area, and were characterized by SEM, TEM and N2 sorption analysis. The hydroxyethylidene-bridged organophosphonate groups were homogeneously incorporated into the network of the hierarchical porous solid, as revealed by FT-IR, MAS NMR, TGA-DSC and XPS measurements. The hybrid materials were used as adsorbents for the liquid phase adsorption of Cu2+ ions in water and the gas phase adsorption of CO2, showing high adsorption capacity and good reusability, which makes them promising adsorbents for practical applications in environmental remediation.
TL;DR: In this article, a variety of perylenetetracarboxy-3,4:9,10-diimide derivatives have been synthesized and the energy differences between the frontier orbitals have been determined using optical spectroscopy (UV and fluorescence).
Abstract: A variety of perylenetetracarboxy-3,4:9,10-diimide derivatives have been synthesized. Particular attention was paid to substituents in positions 1, 6, 7 or 12. The energy differences between the frontier orbitals have been determined using optical spectroscopy (UV and fluorescence). The energy of the lowest unoccupied orbitals (LUMOs) were obtained by cyclic voltammetry. From both studies, the energies of the highest occupied orbitals (HOMOs) were also been calculated. A Hammett-type relationship was observed for the reduction potentials (Ered11/2) when correlated with the σ−ortho parameter. The energies of the frontier orbitals define the domains of application of these compounds. They significantly depend on the substitution in positions 1, 6, 7, or 12.