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Showing papers in "Dalton Transactions in 2013"


Journal ArticleDOI
TL;DR: The analysis of more than five million interatomic "non-bonded" distances has led to the proposal of a consistent set of van der Waals radii for most naturally occurring elements, and its applicability to other element pairs has been tested.
Abstract: The distribution of distances from atoms of a particular element E to a probe atom X (oxygen in most cases), both bonded and intermolecular non-bonded contacts, has been analyzed. In general, the distribution is characterized by a maximum at short E⋯X distances corresponding to chemical bonds, followed by a range of unpopulated distances – the van der Waals gap – and a second maximum at longer distances – the van der Waals peak – superimposed on a random distribution function that roughly follows a d3 dependence. The analysis of more than five million interatomic “non-bonded” distances has led to the proposal of a consistent set of van der Waals radii for most naturally occurring elements, and its applicability to other element pairs has been tested for a set of more than three million data, all of them compared to over one million bond distances.

1,030 citations


Journal ArticleDOI
TL;DR: Potential application of GO in analytical chemistry as a solid sorbent for preconcentration of trace elements and in heavy metal ion pollution cleanup results from its maximum adsorption capacities that are much higher than those of any of the currently reported sorbents.
Abstract: The adsorptive properties of graphene oxide (GO) towards divalent metal ions (copper, zinc, cadmium and lead) were investigated GO prepared through the oxidation of graphite using potassium dichromate was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FT-IR) The results of batch experiments and measurements by flame atomic absorption spectrometry (F-AAS) indicate that maximum adsorption can be achieved in broad pH ranges: 3–7 for Cu(II), 5–8 for Zn(II), 4–8 for Cd(II), 3–7 for Pb(II) The maximum adsorption capacities of Cu(II), Zn(II), Cd(II) and Pb(II) on GO at pH = 5 are 294, 345, 530, 1119 mg g−1, respectively The competitive adsorption experiments showed the affinity in the order of Pb(II) > Cu(II) ≫ Cd(II) > Zn(II) Adsorption isotherms and kinetic studies suggest that sorption of metal ions on GO nanosheets is monolayer coverage and adsorption is controlled by chemical adsorption involving the strong surface complexation of metal ions with the oxygen-containing groups on the surface of GO Chemisorption was confirmed by XPS (binding energy and shape of O1s and C1s peaks) of GO with adsorbed metal ions The adsorption experiments show that the dispersibility of GO in water changes remarkably after complexation of metal ions After adsorption, the tendency to agglomerate and precipitate is observed Excellent dispersibility of GO and strong tendency of GO–Me(II) to precipitate open the path to removal of heavy metals from water solution Potential application of GO in analytical chemistry as a solid sorbent for preconcentration of trace elements and in heavy metal ion pollution cleanup results from its maximum adsorption capacities that are much higher than those of any of the currently reported sorbents

690 citations


Journal ArticleDOI
TL;DR: It has been demonstrated that metal NHC complexes can be used to develop highly efficient metal based drugs with possible applications in the treatment of cancer or infectious diseases.
Abstract: Metal complexes with N-heterocyclic carbene (NHC) ligands are widely used in chemistry due to their catalytic properties and applied for olefin metathesis among other reactions. The enhanced application of this type of organometallics has over the last few years also triggered a steadily increasing number of studies in the fields of medicinal chemistry, which take advantage of the fascinating chemical properties of these complexes. In fact it has been demonstrated that metal NHC complexes can be used to develop highly efficient metal based drugs with possible applications in the treatment of cancer or infectious diseases. Complexes of silver and gold have been biologically evaluated most frequently but also platinum or other transition metals have demonstrated promising biological properties.

446 citations


Journal ArticleDOI
TL;DR: The remarkably increased performance of WO3/g-C3N4 composite photocatalysts was mainly attributed to the synergistic effect between the interface of W o3 and g-C 3N4, including enhanced optical absorption in the visible region, enlarged specific surface areas and the suitable band positions.
Abstract: Novel WO3/g-C3N4 composite photocatalysts were prepared by a calcination process with different mass contents of WO3. The photocatalysts were characterized by thermogravimetric analysis (TG), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). The photocatalytic activity of the photocatalysts was evaluated by degradation of methylene blue (MB) dye and 4-chlorophenol (4-CP) under visible light. The results indicated that the WO3/g-C3N4 composite photocatalysts showed higher photocatalytic activity than both the pure WO3 and pure g-C3N4. The optimum photocatalytic activity of WO3/g-C3N4 at a WO3 mass content of 9.7% under visible light irradiation was up to 4.2 times and 2.9 times as high as that of the pure WO3 and pure g-C3N4, respectively. The remarkably increased performance of WO3/g-C3N4 was mainly attributed to the synergistic effect between the interface of WO3 and g-C3N4, including enhanced optical absorption in the visible region, enlarged specific surface areas and the suitable band positions of WO3/g-C3N4 composites.

436 citations


Journal ArticleDOI
TL;DR: UiO-66(NH2) is proved to perform as an efficient multifunctional visible-light-driven photocatalyst with high stability and considerable recyclability in both the photocatalytic selective oxidation of alcohols to aldehydes using molecular oxygen as oxidant and catalytic reduction of aqueous Cr(VI) to Cr(III) under ambient conditions.
Abstract: Metal–organic frameworks (MOFs) have been arousing a great interest owing to their unique physicochemical properties. In this work, Zr-benzenedicarboxylate (UiO-66) and its derivative, Zr-2-NH2-benzenedicarboxylate (UiO-66(NH2)), are successfully prepared via a facile solvothermal method and applied to photocatalytic reactions. Powder X-ray diffraction (XRD) confirms the isoreticular nature of UiO-66 and UiO-66(NH2), while Fourier transformed infrared spectra (FTIR) prove the effective presence of amino group. UV-vis diffuse reflectance spectra (DRS) show the photoabsorption edge of UiO-66 could be shifted to the visible light region by simply introducing the amino group (–NH2) on the organic ligand. Importantly, UiO-66(NH2) is proved to perform as an efficient multifunctional visible-light-driven photocatalyst with high stability and considerable recyclability in both the photocatalytic selective oxidation of alcohols to aldehydes using molecular oxygen as oxidant and catalytic reduction of aqueous Cr(VI) to Cr(III) under ambient conditions. Furthermore, the possible reaction mechanism has also been investigated in detail. This work makes a systematic attempt to understand the reaction of photocatalytic selective oxidation of alcohols over MOFs and represents the first example to report the identification of MOFs as promising visible-light photocatalysts toward reduction of aqueous Cr(VI). More significantly, our finding also provides a new way to design MOFs-based photocatalysts, that is, by tuning the predesigned ligands with specific functional groups, the optical absorption properties of MOFs can be flexibly modulated, and then the effective solar energy conversion can be expected.

352 citations


Journal ArticleDOI
Deli Jiang1, Linlin Chen1, Jianjun Zhu1, Min Chen1, Weidong Shi1, Jimin Xie1 
TL;DR: It was found that the photodegradation of MB molecules is mainly attributed to the oxidation action of the generated O2˙(-) radicals and partly to the action of h(vb)(+)via direct hole oxidation process.
Abstract: In this work, n-type porous graphite-like C3N4 (denoted as p-g-C3N4) was fabricated and modified with p-type nanostructured BiOI to form a novel BiOI/p-g-C3N4 p–n heterojunction photocatalyst for the efficient photocatalytic degradation of methylene blue (MB). The results show that the BiOI/p-g-C3N4 heterojunction photocatalyst exhibits superior photocatalytic activity compared to pure BiOI and p-g-C3N4. The visible-light photocatalytic activity enhancement of BiOI/p-g-C3N4 heterostructures could be attributed to its strong absorption in the visible region and low recombination rate of the electron–hole pairs because of the heterojunction formed between BiOI and p-g-C3N4. It was also found that the photodegradation of MB molecules is mainly attributed to the oxidation action of the generated O2˙− radicals and partly to the action of hvb+via direct hole oxidation process.

326 citations


Journal ArticleDOI
TL;DR: The potential of 1b for Fe(3+) ions and PA sensing was studied in DMF through the luminescence quenching experiments, which show 1b is a potential turn-off luminescent sensory material for the selective detection of Fe( 3+) ion and PA with detection limits of around 10(-7) M for both of them.
Abstract: A metal–organic framework (MOF) {[Eu2(MFDA)2(HCOO)2(H2O)6]·H2O}n (1) (H2MFDA = 9,9-dimethylfluorene-2,7-dicarboxylic acid) has been solvothermally synthesized and structurally characterized. 1 possesses the three-dimensional pcu type rod-packing structure with one-dimensional rhombic channels. The framework of 1 can reversibly shrink/swell along the c axis upon partial/full release of the water molecules. Correspondingly, the rhombic channels become narrow/large and 1 transforms to narrow-pore 1a/large-pore 1b. 1, 1a and 1b have almost the same excitation and emission spectra with the strong characteristic red-light-emission of Eu(III). A high photoluminescence quantum yield of 77% and long luminescence lifetime of around 1.1 ms was observed for 1. The potential of 1b for Fe3+ ions and PA sensing was studied in DMF through the luminescence quenching experiments, which show 1b is a potential turn-off luminescent sensory material for the selective detection of Fe3+ ions and PA with detection limits of around 10−7 M for both of them. The fluorescence quenching mechanism for Fe3+ ions and PA was also investigated.

323 citations


Journal ArticleDOI
TL;DR: UV-Vis-NIR spectra of O2 activated samples reveal an intense and finely structured d-d quadruplet, unique to Cu-SSZ-13, which is persistent under SCR conditions.
Abstract: Cu-SSZ-13 has been characterized by different spectroscopic techniques and compared with Cu-ZSM-5 and Cu-β with similar Si/Al and Cu/Al ratios and prepared by the same ion exchange procedure. On vacuum activated samples, low temperature FTIR spectroscopy allowed us to appreciate a high concentration of reduced copper centres, i.e. isolated Cu+ ions located in different environments, able to form Cu+(N2), Cu+(CO)n (n = 1, 2, 3), and Cu+(NO)n (n = 1, 2) upon interaction with N2, CO and NO probe molecules, respectively. Low temperature FTIR, DRUV-Vis and EPR analysis on O2 activated samples revealed the presence of different Cu2+ species. New data and discussion are devoted to (i) [Cu–OH]+ species likely balanced by one framework Al atom; (ii) mono(μ-oxo)dicopper [Cu2(μ-O)]2+ dimers observed in Cu-ZSM-5 and Cu-β, but not in Cu-SSZ-13. UV-Vis-NIR spectra of O2 activated samples reveal an intense and finely structured d–d quadruplet, unique to Cu-SSZ-13, which is persistent under SCR conditions. This differs from the 22 700 cm−1 band of the mono(μ-oxo)dicopper species of the O2 activated Cu-ZSM-5, which disappears under SCR conditions. The EPR signal intensity sets Cu-β apart from the others.

305 citations


Journal ArticleDOI
TL;DR: It is shown that the spin orientation of a transition-metal magnetic ion can be easily explained by considering its split d-block levels as unperturbed states with the spin-orbit coupling as perturbation, and that the DM exchange between adjacent spin sites can become comparable in strength to the Heisenberg spin exchange when the two spin sites are not chemically equivalent.
Abstract: The magnetic energy levels of a given magnetic solid are closely packed in energy because the interactions between magnetic ions are weak. Thus, in describing its magnetic properties, one needs to generate its magnetic energy spectrum by employing an appropriate spin Hamiltonian. In this review article we discuss how to determine and specify a necessary spin Hamiltonian in terms of first principles electronic structure calculations on the basis of energy-mapping analysis and briefly survey important concepts and phenomena that one encounters in reading the current literature on magnetic solids. Our discussion is given on a qualitative level from the perspective of magnetic energy levels and electronic structures. The spin Hamiltonian appropriate for a magnetic system should be based on its spin lattice, i.e., the repeat pattern of its strong magnetic bonds (strong spin exchange paths), which requires one to evaluate its Heisenberg spin exchanges on the basis of energy-mapping analysis. Other weaker energy terms such as Dzyaloshinskii–Moriya (DM) spin exchange and magnetocrystalline anisotropy energies, which a spin Hamiltonian must include in certain cases, can also be evaluated by performing energy-mapping analysis. We show that the spin orientation of a transition-metal magnetic ion can be easily explained by considering its split d-block levels as unperturbed states with the spin–orbit coupling (SOC) as perturbation, that the DM exchange between adjacent spin sites can become comparable in strength to the Heisenberg spin exchange when the two spin sites are not chemically equivalent, and that the DM interaction between rare-earth and transition-metal cations is governed largely by the magnetic orbitals of the rare-earth cation.

298 citations


Journal ArticleDOI
TL;DR: This review of supported vanadium oxide catalysts focuses on the fundamental aspects of this novel class of catalytic materials (molecular structures, electronic structures, surface chemistry and structure-reactivity relationships).
Abstract: Supported vanadium oxide catalysts contain a vanadium oxide phase deposited on a high surface area oxide support (e.g., Al2O3, SiO2, TiO2, etc.) and have found extensive applications as oxidation catalysts in the chemical, petroleum and environmental industries. This review of supported vanadium oxide catalysts focuses on the fundamental aspects of this novel class of catalytic materials (molecular structures, electronic structures, surface chemistry and structure–reactivity relationships). The molecular and electronic structures of the supported vanadium oxide phases were determined by the application of modern in situ characterization techniques (Raman, IR, UV-vis, XANES, EXAFS, solid state 51V NMR and isotopic oxygen exchange). The characterization studies revealed that the supported vanadium oxide phase consists of two-dimensional surface vanadia sites dispersed on the oxide supports. Corresponding surface chemistry and reactivity studies demonstrated that the surface vanadia sites are the catalytic active sites for oxidation reactions by supported vanadia catalysts. Combination of characterization and reactivity studies demonstrate that the oxide support controls the redox properties of the surface vanadia sites that can be varied by as much as a factor of ∼103.

285 citations


Journal ArticleDOI
TL;DR: The results provide a new approach for selectively recognizing the most important three trace elements in the human body simultaneously, for Zn(2+) by emission spectra and Fe(2+), Cu( 2+), and Zn (2+)By the naked eye.
Abstract: A simple and low cost chemosensor is described. This sensor could simultaneously detect three biologically important metal ions through fluorogenic (Zn2+) and chromogenic (Fe2+, Cu2+, and Zn2+) methods in aqueous solution. The sensor could function as a “turn-on” fluorescence receptor only to Zn2+ ions. In addition, the sensor could be successfully applied to the detection of intracellular Zn2+. Meanwhile, the sensor displayed an obvious red color upon selective binding with Fe2+. Therefore, the sensor could serve as a useful tool for the discrimination of Fe2+ from Fe3+ in aqueous media. Moreover, the sensor also showed color changes from yellow to colorless upon selective binding with Zn2+ and Cu2+, respectively. The detection limit of the sensor for Cu2+ (1.5 μM) is far below the guidelines of the World Health Organization (30 μM) as the maximum allowable copper concentration in drinking water, and therefore it is capable of being a practical system for the monitoring of Cu2+ concentrations in aqueous samples. These results provide a new approach for selectively recognizing the most important three trace elements in the human body simultaneously, for Zn2+ by emission spectra and Fe2+, Cu2+, and Zn2+ by the naked eye.

Journal ArticleDOI
TL;DR: This perspective summarizes various classes of structurally well-defined group 4 metal initiators developed for lactide ROP and provides observed trends regarding their catalytic performance.
Abstract: Polylactide (PLA) is an attractive polymeric material due to its origin from annually renewable resources and its biodegradability. The ring-opening polymerization (ROP) of lactide initiated by Lewis acidic and oxophilic metal-based catalysts constitutes the method of choice to access PLA in a controlled and stereoselective manner. The design and synthesis of ligand-supported metal complexes to act as effective ROP initiators of lactide monomers have been the subject of numerous investigations over the past decades. In view of their oxophilic nature, well-defined group 4 metal complexes supported by polydentate supporting ligands have appeared as active initiators for lactide ROP. This perspective summarizes various classes of structurally well-defined group 4 metal initiators developed for lactide ROP. It also provides observed trends regarding their catalytic performance. Whenever appropriate and possible, catalyst structure-ROP performance (i.e. activity, control and stereoselectivity) relationships are rationalized.

Journal ArticleDOI
TL;DR: The tests of radical scavengers confirmed that h(+) and ˙OH were the main reactive species for the degradation of RhB and MB, and the composite can be easily reclaimed by sedimentation without any loss of its stability.
Abstract: Spherical Bi2MoO6 nanoarchitectures with scale of 500 nm–2 μm were prepared by a solvothermal reaction using bismuth nitrate and ammonium molybdate as precursors. Ag3PO4 nanoparticles were then deposited onto the surface of Bi2MoO6via a facile deposition–precipitation technique. The photocatalytic tests display that the Ag3PO4/Bi2MoO6 nanocomposites possess a much higher rate for degradation of rhodamine B and methylene blue than the pure Ag3PO4 nanoparticles and Bi2MoO6 under visible light. The catalytic activity of the composite photocatalysts is greatly influenced by the loading level of Ag3PO4. The 50 mol% Ag3PO4-loaded Bi2MoO6 spheres exhibit the highest photocatalytic activity in both the decolorization of RhB and MB. The observed improvement in photocatalytic activity is associated with the extended absorption in the visible light region resulting from the Ag3PO4 nanoparticles, and the effective separation of photogenerated carriers at the Ag3PO4/Bi2MoO6 interfaces. In addition, the composite can be easily reclaimed by sedimentation without any loss of its stability. Moreover, the tests of radical scavengers confirmed that h+ and ˙OH were the main reactive species for the degradation of RhB.

Journal ArticleDOI
Guanyao Wang1, Le-Le Yang1, Yue Li1, Han Song1, Wen-Juan Ruan1, Ze Chang1, Xian-He Bu1 
TL;DR: A luminescent two-dimensional (2D) coordination polymer is demonstrated to be a selective sensing material for the straightforward detection of nitrobenzene via a redox fluorescence quenching mechanism.
Abstract: A luminescent two-dimensional (2D) coordination polymer is demonstrated to be a selective sensing material for the straightforward detection of nitrobenzene via a redox fluorescence quenching mechanism.

Journal ArticleDOI
TL;DR: Photometric characterization indicates the suitability of K(+) compensated CaMoO4:Dy(3+) phosphor for white LED applications.
Abstract: A series of CaMoO4 phosphors doped with trivalent dysprosium (Dy3+) and codoped with potassium (K+) ions were prepared by hydrothermal method. The nanostructures of the as-synthesized phosphors were investigated by X-ray diffraction (XRD). The results reveal that the obtained powder phosphors are single-phase scheelite structure with tetragonal symmetry and the crystallite size is in the range of 10–60 nm. The emission spectra show a bright yellow emission at 576 nm and blue emission at 487 nm. As a charge compensator, K+ ions were incorporated into CaMoO4:Dy3+ phosphors, which enhance the PL intensities depending on the doping concentration of K+. The CIE parameters such as colour coordinates, colour correlated temperature and luminous efficacy of radiation were calculated using spectral energy distribution functions and McCamy's empirical formula. Photometric characterization indicates the suitability of K+ compensated CaMoO4:Dy3+ phosphor for white LED applications.

Journal ArticleDOI
Yuanguo Xu1, Hui Xu1, Lei Wang1, Jia Yan1, Huaming Li1, Yanhua Song1, Liying Huang1, Guobin Cai1 
TL;DR: The results indicated that CNT played an important role, which led to the efficient separation of the photo-generated charge carriers.
Abstract: A novel, multi-walled carbon nanotubes (CNT) modified white C3N4 composite (CNT/white C3N4) with enhanced visible-light-response photoactivity was prepared. The white C3N4 and CNT combined together and formed the CNT/white C3N4 composite due to electrostatically-driven self-assembly with the hydrothermal method. The as-prepared white C3N4 and CNT/white C3N4 composite photocatalyst were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-vis absorption spectra, X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PL). The photoelectrochemical i–t curves were tested using several on–off cycles of light irradiation. The photoactivity of the catalysts was evaluated by degrading methylene blue (MB) dye solution. The results showed that the photoactivity for the degradation of MB solution was in the following order: CNT/white C3N4 composite > C3N4 > the white C3N4. The photoactivity of the CNT/white C3N4 composite was 66.5% and 34.5% higher than that of the white C3N4 sample and that of the C3N4 at 1.5 h, respectively. The degradation rate of the CNT/white C3N4 photocatalyst was almost 8.1 times as high as that of the white C3N4. The results indicated that CNT played an important role, which led to the efficient separation of the photo-generated charge carriers. The reason why the photoactivity of the CNT/white C3N4 was much higher than that of C3N4 and the white C3N4 was discussed. A possible mechanism of CNT on the enhancement of composites' visible light performance was also proposed.

Journal ArticleDOI
TL;DR: This work investigated the feasibility of using the metal-organic frameworks UiO-66(Zr), UuO-67(ZR), H2N-Ui O-66 (Zr) and H2n-MIL-125(Ti) as sorption materials in heat transformations by means of volumetric water adsorption measurements, determination of the heat of Adsorption and a 40-cycle ad/desorption stress test.
Abstract: Sorption-based heat transformation and storage appliances are very promising for utilizing solar heat and waste heat in cooling or heating applications. The economic and ecological efficiency of sorption-based heat transformation depends on the availability of suitable hydrophilic and hydrothermally stable sorption materials. We investigated the feasibility of using the metal–organic frameworks UiO-66(Zr), UiO-67(Zr), H2N-UiO-66(Zr) and H2N-MIL-125(Ti) as sorption materials in heat transformations by means of volumetric water adsorption measurements, determination of the heat of adsorption and a 40-cycle ad/desorption stress test. The amino-modified compounds H2N-UiO-66 and H2N-MIL-125 feature high heat of adsorption (89.5 and 56.0 kJ mol−1, respectively) and a very promising H2O adsorption isotherm due to their enhanced hydrophilicity. For H2N-MIL-125 the very steep rise of the H2O adsorption isotherm in the 0.1 < p/p0 < 0.2 region is especially beneficial for the intended heat pump application.

Journal ArticleDOI
TL;DR: Informative magnetic susceptibility measurements show that the same carboxylate bridging fashion of the PBDA ligand results in the different magnetic properties occurring within the heterometallic coordination polymers.
Abstract: A new zinc compound, together with a corresponding series of Zn-4f heterometallic coordination polymers, namely, [Zn(H2PBDA)(PBDA)]n (1), {[Ln2(PBDA)2·2H2O] [Zn2(PBDA)2Cl2]}n [H2PBDA = 3-(pyridin-3-yl-oxy) benzene-1,2-dicarboxylic acid, and Ln = Pr(2), Nd(3), Eu(4), Gd(5), Dy(6), Ho(7), Er(8)] have been hydrothermally synthesized and characterized systematically. Polymers 2–8 feature two-dimensional (2D) 4,4 networks, containing the original 1D heterometallic double stranded chains composed of [Ln2Zn2(PBDA)2] entities. The extensive hydrogen bonding and π–π stacking interactions were observed to stabilize the extended architectures. The luminescence emission spectra of the polymers vary depending on the lanthanide(III) ion present. Informative magnetic susceptibility measurements show that the same carboxylate bridging fashion of the PBDA ligand results in the different magnetic properties occurring within the heterometallic coordination polymers. In addition, polymer 6 exhibits an interesting slow magnetic relaxation behavior at lower temperatures.

Journal ArticleDOI
TL;DR: Aerosol-assisted CVD is a solution-based process which relies on the solubility of the precursor, rather than its volatility and thus vastly extends the range of potentially applicable precursors, and offers extra means to control film morphology and concurrently the properties of the deposited materials.
Abstract: The production of thin films of materials has become the attention of a great deal of research throughout academia and industry worldwide owing to the array of applications which utilise them, including electronic devices, gas sensors, solar cells, window coatings and catalytic systems. Whilst a number of deposition techniques are in common use, chemical vapour deposition (CVD) is an attractive process for the production of a wide range of materials due to the control it offers over film composition, coverage and uniformity, even on large scales. Conventional CVD processes can be limited, however, by the need for suitably volatile precursors. Aerosol-assisted (AA)CVD is a solution-based process which relies on the solubility of the precursor, rather than its volatility and thus vastly extends the range of potentially applicable precursors. In addition, AACVD offers extra means to control film morphology and concurrently the properties of the deposited materials. In this perspective we discuss the AACVD process, the influence of deposition conditions on film characteristics and a number of materials and applications to which AACVD has been found beneficial.

Journal ArticleDOI
TL;DR: The structural features of copper(II), nickel (II), cobalt (II) and zinc(II) complexes with the antimicrobial drugs quinolones and non-steroidal anti-inflammatory drugs (NSAIDs) as ligands and the biological activity of selected complexes are investigated.
Abstract: The structural features of copper(II), nickel(II), cobalt(II) and zinc(II) complexes with the antimicrobial drugs quinolones and non-steroidal anti-inflammatory drugs (NSAIDs) as ligands are discussed. The binding properties of these complexes to biomolecules (calf-thymus DNA, bovine or human serum albumin) are presented and evaluated. The biological activity (antimicrobial, antioxidant and antiproliferative) of selected complexes is investigated. Further perspectives concerning the synthesis and the biological activity of novel complexes with quinolones or NSAIDs attractive to synthetic chemists, biochemists and/or biologists are presented.

Journal ArticleDOI
TL;DR: The potential of 1a for nitro explosive sensing is studied through luminescence quenching experiments, which show that 1a is a potential luminescent sensory material for nitroglycerine explosives.
Abstract: A microporous metal–organic framework (MOF) Eu3(MFDA)4(NO3)(DMF)3 (1, H2MFDA = 9,9-dimethylfluorene-2,7-dicarboxylic acid) has been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction. 1 is a three-dimensional coordination polymer with pcu type rod-packing structure, through which 1D rhombic channels penetrate. The solvent-free form 1a could be obtained by direct heating of 1. Both 1 and 1a exhibit high intensity red light emissions with high quantum yields and long luminescence lifetimes when excited at 336 nm at ambient temperature. The potential of 1a for nitro explosive sensing is studied through luminescence quenching experiments, which show that 1a is a potential luminescent sensory material for nitro explosives.

Journal ArticleDOI
TL;DR: It is found that by using fluorescence intensity ratio technique, appreciable sensitivity for temperature measurement can be achieved from the present phosphor material, which indicates its applicability as a high temperature sensing probe.
Abstract: The codoping effect of Zn2+ ions on luminescence emission in visible and near infrared (NIR) regions of Y2O3:Ho3+–Yb3+ phosphor prepared by low temperature combustion process have been investigated under 980 nm and 448 nm excitations. The phase and crystallite size of the prepared phosphor were determined by X-ray diffraction analysis and processes involved in the upconversion mechanism have been discussed in detail via pump power dependence, decay curve analysis and a suitable energy level diagram. The temperature sensing performance of the developed material has also been investigated by measuring the fluorescence intensity ratio of the blue upconversion emission bands centred at 465 nm and 491 nm up to 673 K. It is found that by using fluorescence intensity ratio technique, appreciable sensitivity for temperature measurement can be achieved from the present phosphor material, which indicates its applicability as a high temperature sensing probe. The fabrication of green LEDs using the developed phosphor material has also been suggested.

Journal ArticleDOI
TL;DR: A simple solvothermal method to fabricate metal-organic framework NH2-MIL-53(Al) crystals with controllable size and morphology just by altering the ratio of water in the DMF-water mixed solvent system without the addition of any surfactants or capping agents is presented.
Abstract: We present here a simple solvothermal method to fabricate metal–organic framework NH2-MIL-53(Al) crystals with controllable size and morphology just by altering the ratio of water in the DMF–water mixed solvent system without the addition of any surfactants or capping agents. With increasing the volume ratio of water in the mixed solvents, a series of NH2-MIL-53(Al) crystals with different sizes and morphologies were synthesized. The average size of the smallest crystal is 76 ± 20 nm, which provides us a simple and environmentally friendly way to prepare nanoscale MOFs. The largest BET surface area of these samples is 1882 m2 g−1 that is mainly contributed by its micropore surface area, and its corresponding micropore volume is 0.83 cm3 g−1, which have greatly extended its application in the fields of gas adsorption and postsynthetic modification. All these samples were characterized by SEM, XRD, N2 adsorption/desorption, TGA and FT-IR. Then a mechanism for the impact of the water ratio on the crystal size and morphology is presented and discussed.

Journal ArticleDOI
TL;DR: A concise survey of phosphonate coupling molecules is presented, including details on their coordination chemistry, their use in the surface modification of inorganic substrates with self-assembled monolayers, and the analytical techniques available to characterize their environment in nanomaterials.
Abstract: Phosphonic acids are increasingly being used for controlling surface and interface properties in hybrid or composite materials, (opto)electronic devices and in the synthesis of nanomaterials. In this perspective article, a concise survey of phosphonate coupling molecules is first presented, including details on their coordination chemistry, their use in the surface modification of inorganic substrates with self-assembled monolayers, and the analytical techniques available to characterize their environment in nanomaterials. Then, some of their recent applications in the development of organic electronic devices, photovoltaic cells, biomaterials, biosensors, supported catalysts and sorbents, corrosion inhibitors, and nanostructured composite materials, are presented. In the last part of the article, a brief overview of recent progress in the use of phosphonate ligands for the preparation of molecular nanomaterials like metal organic frameworks and functionalized polyoxometalates is given.

Journal ArticleDOI
TL;DR: The synthesised PB-1, by a common stoichiometric aqueous reaction between 4Fe(3+) and 3[Fe(II)(CN)6](4-), showed much more efficient Cs(+) adsorption ability than did the commercially available PB-2.
Abstract: We have revealed the fundamental mechanism of specific Cs+ adsorption into Prussian blue (PB) in order to develop high-performance PB-based Cs+ adsorbents in the wake of the Fukushima nuclear accident. We compared two types of PB nanoparticles with formulae of FeIII4[FeII(CN)6]3·xH2O (x = 10–15) (PB-1) and (NH4)0.70FeIII1.10[FeII(CN)6]·1.7H2O (PB-2) with respect to the Cs+ adsorption ability. The synthesised PB-1, by a common stoichiometric aqueous reaction between 4Fe3+ and 3[FeII(CN)6]4−, showed much more efficient Cs+ adsorption ability than did the commercially available PB-2. A high value of the number of waters of crystallization, x, of PB-1 was caused by a lot of defect sites (vacant sites) of [FeII(CN)6]4− moieties that were filled with coordination and crystallization water molecules. Hydrated Cs+ ions were preferably adsorbed via the hydrophilic defect sites and accompanied by proton-elimination from the coordination water. The low number of hydrophilic sites of PB-2 was responsible for its insufficient Cs+ adsorption ability.

Journal ArticleDOI
TL;DR: In this paper, the nucleation and growth of ZnO nanostructures in liquid media by classical and non-classical (i.e., particle-based) crystallization pathways are discussed.
Abstract: Among all the functional materials, ZnO plays an outstanding role in terms of chemical and physical properties, but also in terms of morphological variety and the number of reported synthesis approaches. Complex shapes and hierarchical architectures make ZnO a perfect example to study chemical and crystallization mechanisms. In this review article, we will discuss the nucleation and growth of ZnO nanostructures in liquid media by classical and non-classical (i.e., particle-based) crystallization pathways. We elaborate the chemical conditions and parameters that are responsible for the occurrence of one or the other pathway.

Journal ArticleDOI
TL;DR: This paper presents a comparative study of Cu(II) decontamination by three different carbonaceous materials, i.e., graphene oxide, multiwalled carbon nanotubes, and activated carbon, and how the surface area and the total concentration of acidic functional groups influencing the adsorption capacities of the threecarbonaceous materials for Cu( II) removal were elucidated.
Abstract: This paper presents a comparative study of Cu(II) decontamination by three different carbonaceous materials, i.e., graphene oxide, multiwalled carbon nanotubes, and activated carbon. The three carbonaceous materials were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, N2-BET surface area analysis, and potentiometric acid–base titrations in detail. Also, Cu(II) adsorption on the three types of carbonaceous materials as a function of pH and Cu(II) ion concentration were investigated. The constant capacitance model was used to determine the appropriate surface reactions of Cu(II) adsorption on carbonaceous materials with the aid of FITEQL 4.0 software. In addition, how the surface area and the total concentration of acidic functional groups influencing the adsorption capacities of the three carbonaceous materials for Cu(II) removal were elucidated. The results have an important role in predicting the adsorption capacity of surface modified carbonaceous materials.

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TL;DR: The interesting results in CO(2) adsorption properties of this new Cu-based MOF material, especially its isosteric heat of adsorptive properties make it a suitable MOF to be further evaluated under real conditions of industrial CO( 2) capture.
Abstract: Herein, we report on a new Cu-based MOF material, Cu2(dhtp), structurally homologous to the honeycomb-like M2(dhtp) series. This has been crystallized under solvothermal conditions using copper nitrate and 2,5-dihydroxyterephthalic acid as an organic linker, being the nature of the co-solvent in the synthesis media an important variable over the final physical properties of the material. The presence of isopropanol as a co-solvent leads to the formation of a pure crystalline phase with textural properties comparable to M2(dhtp) homologues. The interesting results in CO2 adsorption properties of this new material, especially its isosteric heat of adsorption, make it a suitable MOF to be further evaluated under real conditions of industrial CO2 capture.

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TL;DR: The Fe3O4/GO composite may be a promising sorption material for the separation and preconcentration of heavy metal ions from aqueous solutions in environmental pollution cleanup.
Abstract: A composite of porous Fe3O4 hollow microspheres/graphene oxide (Fe3O4/GO) has been fabricated through a facile self-assembly approach. Driven by the mutual electrostatic interactions, the amine-functionalized Fe3O4 microspheres prepared by a hydrothermal method and then modified by 3-aminopropyltrimethoxysilane were decorated with negatively-charged GO sheets. The Fe3O4 microspheres were hollow with porous surfaces and the surfaces were successfully modified with the amine, which was confirmed by Fourier transform infrared spectroscopy. The specific saturation magnetization of Fe3O4/GO was 37.8 emu g−1. The sorption performance of Fe3O4/GO for Cr(VI) was evaluated. The maximum sorption capacity for Cr(VI) on Fe3O4/GO was 32.33 mg g−1, which was much higher than that of Fe3O4 microspheres. The GO sheets could not only prevent agglomeration of the Fe3O4 microspheres and enable a good dispersion of these oxide microspheres, but also substantially enhance the specific surface area of the composite. The Fe3O4/GO composite may be a promising sorption material for the separation and preconcentration of heavy metal ions from aqueous solutions in environmental pollution cleanup.

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TL;DR: Three new functionalized UiO-66-X frameworks incorporating BDC-X (BDC: 1,4-benzenedicarboxylate) linkers have been synthesized by a solvothermal method using conventional electric heating.
Abstract: Three new functionalized UiO-66-X (X = –SO3H, 1; –CO2H, 2; –I; 3) frameworks incorporating BDC-X (BDC: 1,4-benzenedicarboxylate) linkers have been synthesized by a solvothermal method using conventional electric heating. The as-synthesized (AS) as well as the thermally activated compounds were characterized by X-ray powder diffraction (XRPD), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, thermogravimetric (TG), and elemental analysis. The occluded H2BDC-X molecules can be removed by exchange with polar solvent molecules followed by thermal treatment under vacuum leading to the empty-pore forms of the title compounds. Thermogravimetric analysis (TGA) and temperature-dependent XRPD (TDXRPD) experiments indicate that 1, 2 and 3 are stable up to 260, 340 and 360 °C, respectively. The compounds maintain their structural integrity in water, acetic acid and 1 M HCl, as verified by XRPD analysis of the samples recovered after suspending them in the respective liquids. As confirmed by N2, CO2 and CH4 sorption analyses, all of the thermally activated compounds exhibit significant microporosity (SLangmuir: 769–842 m2 g−1), which are comparable to that of the parent UiO-66 compound. Compared to the unfunctionalized UiO-66 compound, all the three functionalized solids possess higher ideal selectivity in adsorption of CO2 over CH4 at 33 °C.