Open AccessArticle
Synthesis and Characterization of a Sulfonyl- and Iminophosphoryl-Functionalized Methanide and Methandiide
Inorganics 2016, 4(4), 40; doi:10.3390/inorganics4040040 -
Abstract
The synthesis of [H2C(PPh2=NSiMe3)(SO2Ph)] (1) and its mono- and dimetalation are reported. Due to the strong anion-stabilizing abilities of the iminophosphoryl and the sulfonyl group monometalation to 1-K and dimetalation to 1-Li2
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The synthesis of [H2C(PPh2=NSiMe3)(SO2Ph)] (1) and its mono- and dimetalation are reported. Due to the strong anion-stabilizing abilities of the iminophosphoryl and the sulfonyl group monometalation to 1-K and dimetalation to 1-Li2 proceed smoothly with potassium hydride and methyllithium, respectively. Both compounds could be isolated in high yields and were characterized by NMR spectroscopy as well as XRD analysis. The methanide 1-K forms a coordination polymer in the solid state, while in case of the methandiide a tetrameric structure is observed. The latter features an unusual structural motif consisting of two (SO2Li)2 eight-membered rings, which are connected with each other via the methandiide carbon atoms and additional lithium atoms. With increasing metalation a contraction of the P–C–S linkage is observed, which is well in line with the increased charge at the central carbon atom and involved electrostatic interactions. Full article
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Open AccessArticle
Reduction of Bromo- and Iodo-2,6-bis(diphenylphosphanylmethyl)benzene with Magnesium and Calcium
Inorganics 2016, 4(4), 39; doi:10.3390/inorganics4040039 -
Abstract
Arylmagnesium and -calcium reagents are easily accessible; however, ether degradation processes limit storability, especially of the calcium-based heavy Grignard reagents. Ortho-bound substituents with phosphanyl donor sites usually block available coordination sites and stabilize such complexes. The reaction of bromo-2,6-bis(diphenylphosphanylmethyl)benzene (1a) with
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Arylmagnesium and -calcium reagents are easily accessible; however, ether degradation processes limit storability, especially of the calcium-based heavy Grignard reagents. Ortho-bound substituents with phosphanyl donor sites usually block available coordination sites and stabilize such complexes. The reaction of bromo-2,6-bis(diphenylphosphanylmethyl)benzene (1a) with magnesium in tetrahydrofuran yields [Mg{C6H3-2,6-(CH2PPh2)2}2] (2) after recrystallization from 1,2-dimethoxyethane. However, the similarly performed reduction of bromo- (1a) and iodo-2,6-bis(diphenylphosphanylmethyl)benzene (1b) with calcium leads to ether cleavage and subsequent degradation products. α-Deprotonation of tetrahydrofuran (THF) yields 1,3-bis(diphenylphosphanylmethyl)benzene. Furthermore, the insoluble THF adducts of dimeric calcium diphenylphosphinate halides, [(thf)3Ca(X)(µ-O2PPh2)]2 [X = Br (3a), I (3b)], precipitate verifying ether decomposition and cleavage of P–C bonds. Ether adducts of calcium halides (such as [(dme)2(thf)CaBr2] (4)) form, supporting the initial Grignard reaction and a subsequent Schlenk-type dismutation reaction. Full article
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Open AccessReview
Structural Classification of Quasi-One-Dimensional Ternary Nitrides
Inorganics 2016, 4(4), 37; doi:10.3390/inorganics4040037 -
Abstract
This review focuses on the crystal structural features of ternary (mixed-metal) quasi-one-dimensional nitrides i.e., nitrides containing (cation-N3−) coordination polyhedra sharing either corners, edges, or faces, arranged in linear chains, and intercalated by a counter ion. The current relevance of these nitrides,
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This review focuses on the crystal structural features of ternary (mixed-metal) quasi-one-dimensional nitrides i.e., nitrides containing (cation-N3−) coordination polyhedra sharing either corners, edges, or faces, arranged in linear chains, and intercalated by a counter ion. The current relevance of these nitrides, and of quasi-one-dimensional compounds in general, lies in the fact that they are closely related to the pure one-dimensional systems (i.e., nanowires), which are vastly researched for their amazing properties closely related to their low dimensionality. A number of these properties were firstly discovered in quasi-one-dimensional compounds, highlighting the importance of expanding knowledge and research in this area. Furthermore, unlike oxides, nitrides and other non-oxide compounds are less developed, hence more difficult to categorise into structural classes that can then be related to other classes of compounds, leading to a fuller picture of structure–properties relationship. Within this context, this review aims to categorise and describe a number of ternary (mixed-metal) quasi-one-dimensional nitrides according to their structural features, specifically, the polyhedra forming the one-dimensional chains. Full article
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Open AccessArticle
Steroid-Functionalized Titanocenes: Docking Studies with Estrogen Receptor Alpha
Inorganics 2016, 4(4), 38; doi:10.3390/inorganics4040038 -
Abstract
Estrogen receptor alpha (ERα) is a transcription factor that is activated by hormones, with 17β-estradiol being its most active agonist endogenous ligand. ERα is also activated or inactivated by exogenous ligands. ER is overexpressed in hormone-dependent breast cancer, and one of the treatments
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Estrogen receptor alpha (ERα) is a transcription factor that is activated by hormones, with 17β-estradiol being its most active agonist endogenous ligand. ERα is also activated or inactivated by exogenous ligands. ER is overexpressed in hormone-dependent breast cancer, and one of the treatments for this type of cancer is the use of an ER antagonist to halt cell proliferation. We have previously reported four steroid-functionalized titanocenes: pregnenolone, dehydroepiandrosterone (DHEA), trans-androsterone, and androsterone. These steroids have hormonal activity as well as moderate antiproliferative activity, thus these steroids could act as vectors for the titanocene dichloride to target hormone-dependent cancers. Also, these steroids could increase the antiproliferative activity of the resulting titanocenes based on synergism. In order to elucidate which factors contribute to the enhanced antiproliferative activity of these steroid-functionalized titanocenes, we performed docking studies between ERα and the titanocenes and the steroids. The binding affinities and type of bonding interactions of the steroid-functionalized titanocenes with ERα are herein discussed. Full article
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Open AccessArticle
PP-Rotation, P-Inversion and Metathesis in Diphosphines Studied by DFT Calculations: Comments on Some Literature Conflicts
Inorganics 2016, 4(4), 36; doi:10.3390/inorganics4040036 -
Abstract
The potential energy surface for internal rotation about the phosphorus–phosphorus bond was calculated at the PCMDCM/B3LYP/6-311++G(d,p) computational level for a set of eight symmetrical, unsymmetrical and P-stereogenic diphosphines; H4P2, Me4P2, (CF3
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The potential energy surface for internal rotation about the phosphorus–phosphorus bond was calculated at the PCMDCM/B3LYP/6-311++G(d,p) computational level for a set of eight symmetrical, unsymmetrical and P-stereogenic diphosphines; H4P2, Me4P2, (CF3)4P2, Ph4P2, Me2P–P(CF3)2, Me2P–PPh2, and the meso- and dl-isomers of Me(CF3)P–PMe(CF3) and MePhP–PMePh. Certain trends in the data were elucidated and compared with conflicting data from the literature regarding the relative population of anti and gauche rotational isomers. The pyramidal inversion barriers (stereomutation barriers in P-stereogenic cases) for the same set of diphosphines was estimated through the inversion transition states and also compared to literature values. Finally, the Me4P2 + (CF3)4P2 → 2Me2(CF3)2P2 metathesis reaction was also explored to evaluate its feasibility versus inversion. The finding of larger barriers in the metathesis than in the inversion rules in favour of an inversion mechanism for the stereomutation of P-stereogenic diphosphines. Full article
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Open AccessArticle
In Situ Studies and Magnetic Properties of the Cmcm Polymorph of LiCoPO4 with a Hierarchical Dumbbell-Like Morphology Synthesized by Easy Single-Step Polyol Synthesis
Inorganics 2016, 4(4), 35; doi:10.3390/inorganics4040035 -
Abstract
LiCoPO4 (LCP) exists in three different structural modifications: LCP-Pnma (olivine structure), LCP-Pn21a (KNiPO4 structure type), and LCP-Cmcm (Na2CrO4 structure type). The synthesis of the LCP-Cmcm polymorph has been reported via high
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LiCoPO4 (LCP) exists in three different structural modifications: LCP-Pnma (olivine structure), LCP-Pn21a (KNiPO4 structure type), and LCP-Cmcm (Na2CrO4 structure type). The synthesis of the LCP-Cmcm polymorph has been reported via high pressure/temperature solid-state methods and by microwave-assisted solvothermal synthesis. Phase transitions from both LCP-Pn21a and LCP-Cmcm to LCP-Pnma upon heating indicates a metastable behavior. However, a precise study of the structural changes during the heating process and the magnetic properties of LCP-Cmcm are hitherto unknown. Herein, we present the synthesis and characterization of LCP-Cmcm via a rapid and facile soft-chemistry approach using two different kinetically controlled pathways, solvothermal and polyol syntheses, both of which only require relatively low temperatures (~200 °C). Additionally, by polyol, method a dumbbell-like morphology is obtained without the use of any additional surfactant or template. A temperature-dependent in situ powder XRD shows a transition from LCP-Cmcm at room temperature to LCP-Pnma and finally to LCP-Pn21a at 575 and 725 °C, respectively. In addition to that, the determination of the magnetic susceptibility as a function of temperature indicates a long-range antiferromagnetic order below TN = 11 K at 10 kOe and 9.1 K at 25 kOe. The magnetization curves suggests the presence of a metamagnetic transition. Full article
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Open AccessCommunication
Metal-Free Reduction of Phosphine Oxides Using Polymethylhydrosiloxane
Inorganics 2016, 4(4), 34; doi:10.3390/inorganics4040034 -
Abstract
A simple protocol is presented here for the use of inexpensive polymethylhydrosiloxane (PMHS), a waste product of the silicon industry, as stoichiometric reducing agent for phosphine oxides to phosphines, a highly desirable reaction to recover P-based ligands from their spent form. The reactions
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A simple protocol is presented here for the use of inexpensive polymethylhydrosiloxane (PMHS), a waste product of the silicon industry, as stoichiometric reducing agent for phosphine oxides to phosphines, a highly desirable reaction to recover P-based ligands from their spent form. The reactions were studied by screening parameters, such as substrate to reductant ratio, temperature and reaction time, achieving good conversions and selectivities. Full article
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Open AccessArticle
Water-Soluble Cellulose Derivatives Are Sustainable Additives for Biomimetic Calcium Phosphate Mineralization
Inorganics 2016, 4(4), 33; doi:10.3390/inorganics4040033 -
Abstract
The effect of cellulose-based polyelectrolytes on biomimetic calcium phosphate mineralization is described. Three cellulose derivatives, a polyanion, a polycation, and a polyzwitterion were used as additives. Scanning electron microscopy, X-ray diffraction, IR and Raman spectroscopy show that, depending on the composition of the
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The effect of cellulose-based polyelectrolytes on biomimetic calcium phosphate mineralization is described. Three cellulose derivatives, a polyanion, a polycation, and a polyzwitterion were used as additives. Scanning electron microscopy, X-ray diffraction, IR and Raman spectroscopy show that, depending on the composition of the starting solution, hydroxyapatite or brushite precipitates form. Infrared and Raman spectroscopy also show that significant amounts of nitrate ions are incorporated in the precipitates. Energy dispersive X-ray spectroscopy shows that the Ca/P ratio varies throughout the samples and resembles that of other bioinspired calcium phosphate hybrid materials. Elemental analysis shows that the carbon (i.e., polymer) contents reach 10% in some samples, clearly illustrating the formation of a true hybrid material. Overall, the data indicate that a higher polymer concentration in the reaction mixture favors the formation of polymer-enriched materials, while lower polymer concentrations or high precursor concentrations favor the formation of products that are closely related to the control samples precipitated in the absence of polymer. The results thus highlight the potential of (water-soluble) cellulose derivatives for the synthesis and design of bioinspired and bio-based hybrid materials. Full article
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Open AccessArticle
Direct Catalytic Conversion of Cellulose to 5-Hydroxymethylfurfural Using Ionic Liquids
Inorganics 2016, 4(4), 32; doi:10.3390/inorganics4040032 -
Abstract
Cellulose is the single largest component of lignocellulosic biomass and is an attractive feedstock for a wide variety of renewable platform chemicals and biofuels, providing an alternative to petrochemicals and petrofuels. This potential is currently limited by the existing methods of transforming this
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Cellulose is the single largest component of lignocellulosic biomass and is an attractive feedstock for a wide variety of renewable platform chemicals and biofuels, providing an alternative to petrochemicals and petrofuels. This potential is currently limited by the existing methods of transforming this poorly soluble polymer into useful chemical building blocks, such as 5-hydroxymethylfurfural (HMF). Ionic liquids have been used successfully to separate cellulose from the other components of lignocellulosic biomass and so the use of the same medium for the challenging transformation of cellulose into HMF would be highly attractive for the development of the biorefinery concept. In this report, ionic liquids based on 1-butyl-3-methylimidazolium cations [C4C1im]+ with Lewis basic (X = Cl) and Brønsted acidic (X = HSO4) anions were used to investigate the direct catalytic transformation of cellulose to HMF. Variables probed included the composition of the ionic liquid medium, the metal catalyst, and the reaction conditions (temperature, substrate concentration). Lowering the cellulose loading and optimising the temperature achieved a 58% HMF yield after only one hour at 150 °C using a 7 mol % loading of the CrCl3 catalyst. This compares favourably with current literature procedures requiring much longer reactions times or approaches that are difficult to scale such as microwave irradiation. Full article
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Open AccessEditorial
Rare Earth and Actinide Complexes
Inorganics 2016, 4(4), 31; doi:10.3390/inorganics4040031 -
Abstract The rare earth metals (scandium, yttrium, lanthanum and the subsequent 4f elements) and actinides (actinium and the 5f elements) are vital components of our technology-dominated society.[...] Full article
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Open AccessArticle
η12-P-Pyrazolylphosphaalkene Complexes of Ruthenium(0)
Inorganics 2016, 4(4), 30; doi:10.3390/inorganics4040030 -
Abstract
An extended range of novel ruthenium phosphaalkene complexes of the type [Ru{η1-N2-P,C-P(pz′)=CH(SiMe2R)}(CO)(PPh3)2] (R = Tol, C6H4CF3-p; pz′ = pz
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An extended range of novel ruthenium phosphaalkene complexes of the type [Ru{η1-N2-P,C-P(pz′)=CH(SiMe2R)}(CO)(PPh3)2] (R = Tol, C6H4CF3-p; pz′ = pzMe2, pzCF3, pzMe,CF3; R = Me, C6H4CF3-p; pz′ = pzPh) have been prepared from the respective ruthenaphosphaalkenyls [Ru{P=CH(SiMe2R)}Cl(CO)(PPh3)2] upon treatment with Lipz′. Where R = C6H4CF3-p and pz′ = pzMe2 the complex is characterized by single crystal X-ray diffraction, only the second example of such species being structurally characterized. This indicates enhanced pyramidalisation of the alkenic carbon center when compared with precedent data (R = Me, pz′ = pz) implying an enhanced Ru→π*PC contribution, which can be correlated with the greater donor power of pzMe2. This is similarly reflected in spectroscopic data that reveal significant influence of the pyrazolyl substituents upon the phosphaalkene, stronger donors imparting significantly enhanced shielding to phosphorus; in contrast, a much lesser influence if noted for the silyl substituents. Full article
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Open AccessArticle
Synthesis and Structure Determination of the Quaternary Zinc Nitride Halides Zn2NX1−yX′y (X, X′ = Cl, Br, I; 0 < y < 1)
Inorganics 2016, 4(4), 29; doi:10.3390/inorganics4040029 -
Abstract
The quaternary series Zn2NCl1−yBry and Zn2NBr1−yIy were synthesized from solid-liquid reactions between zinc nitride and the respective zinc halides in closed ampoules, and the evolution of their crystal structures was investigated
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The quaternary series Zn2NCl1−yBry and Zn2NBr1−yIy were synthesized from solid-liquid reactions between zinc nitride and the respective zinc halides in closed ampoules, and the evolution of their crystal structures was investigated by single-crystal and powder X-ray diffraction. Zn2NX1−yX′y (X, X′ = Cl, Br, I) adopts the anti-β-NaFeO2 motif in which each nitride ion is tetrahedrally coordinated by four zinc cations, and the halide anions are located in the voids of the skeleton formed by corner-sharing [NZn4] tetrahedra. While Zn2NCl1−yBry crystallizes in the acentric orthorhombic space group Pna21 (No. 33), isotypic to Zn2NX (X = Cl, Br), the structure of Zn2NBr1−yIy is a function of the iodide concentration, namely, Zn2NBr (Pna21) for low iodine content and Zn2NI (Pnma) for higher (y ≥ 0.38). Full article
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Open AccessArticle
The Role of Anisotropic Exchange in Single Molecule Magnets: A CASSCF/NEVPT2 Study of the Fe4 SMM Building Block [Fe2(OCH3)2(dbm)4] Dimer
Inorganics 2016, 4(4), 28; doi:10.3390/inorganics4040028 -
Abstract
The rationalisation of single molecule magnets’ (SMMs) magnetic properties by quantum mechanical approaches represents a major task in the field of the Molecular Magnetism. The fundamental interpretative key of molecular magnetism is the phenomenological Spin Hamiltonian and the understanding of the role of
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The rationalisation of single molecule magnets’ (SMMs) magnetic properties by quantum mechanical approaches represents a major task in the field of the Molecular Magnetism. The fundamental interpretative key of molecular magnetism is the phenomenological Spin Hamiltonian and the understanding of the role of its different terms by electronic structure calculations is expected to steer the rational design of new and more performing SMMs. This paper deals with the ab initio calculation of isotropic and anisotropic exchange contributions in the Fe(III) dimer [Fe2(OCH3)2(dbm)4]. This system represents the building block of one of the most studied Single Molecule Magnets ([Fe4RC(CH2O)3)2(dpm)6] where R can be an aliphatic chain or a phenyl group just to name the most common functionalization groups) and its relatively reduced size allows the use of a high computational level of theory. Calculations were performed using CASSCF and NEVPT2 approaches on the X-ray geometry as assessment of the computational protocol, which has then be used to evinced the importance of the outer coordination shell nature through organic ligand modelization. Magneto-structural correlations as function of internal degrees of freedom for isotropic and anisotropic exchange contributions are also presented, outlining, for the first time, the extremely rapidly changing nature of the anisotropic exchange coupling. Full article
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Open AccessArticle
Optical Properties of Heavily Fluorinated Lanthanide Tris β-Diketonate Phosphine Oxide Adducts
Inorganics 2016, 4(3), 27; doi:10.3390/inorganics4030027 -
Abstract
The construction of lanthanide(III) chelates that exhibit superior photophysical properties holds great importance in biological and materials science. One strategy to increase the luminescence properties of lanthanide(III) chelates is to hinder competitive non-radiative decay processes through perfluorination of the chelating ligands. Here, the
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The construction of lanthanide(III) chelates that exhibit superior photophysical properties holds great importance in biological and materials science. One strategy to increase the luminescence properties of lanthanide(III) chelates is to hinder competitive non-radiative decay processes through perfluorination of the chelating ligands. Here, the synthesis of two families of heavily fluorinated lanthanide(III) β-diketonate complexes bearing monodentate perfluorinated tris phenyl phosphine oxide ligands have been prepared through a facile one pot reaction [Ln(hfac)3{(ArF)3PO}(H2O)] and [Ln(F7-acac)3{(ArF)3PO}2] (where Ln = Sm3+, Eu3+, Tb3+, Er3+ and Yb3+). Single crystal X-ray diffraction analysis in combination with photophysical studies have been performed to investigate the factors responsible for the differences in the luminescence lifetimes and intrinsic quantum yields of the complexes. Replacement of both bound H2O and C–H oscillators in the ligand backbone has a dramatic effect on the photophysical properties of the complexes, particularly for the near infra-red emitting ion Yb3+, where a five fold increase in luminescence lifetime and quantum yield is observed. The complexes [Sm(hfac)3{(ArF)3PO}(H2O)] (1), [Yb(hfac)3{(ArF)3PO}(H2O)] (5), [Sm(F7-acac)3{(ArF)3PO}2] (6) and [Yb(F7-acac)3{(ArF)3PO}2] (10) exhibit unusually long luminescence lifetimes and attractive intrinsic quantum yields of emission in fluid solution (ΦLn = 3.4% (1); 1.4% (10)) and in the solid state (ΦLn = 8.5% (1); 2.0% (5); 26% (6); 11% (10)), which are amongst the largest values for this class of compounds to date. Full article
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Open AccessCommunication
Zirconium-Catalyzed Alkene Hydrophosphination and Dehydrocoupling with an Air-Stable, Fluorescent Primary Phosphine
Inorganics 2016, 4(3), 26; doi:10.3390/inorganics4030026 -
Abstract Zirconium-catalyzed alkene hydrophosphination and dehydrocoupling with an air-stable, fluorescent primary phosphine 8-[(4-phosphino)phenyl]-4,4-dimethyl-1,3,5,7-tetramethyl-2,6-diethyl-4-bora-3a,4a-diaza-s-indacene furnishes fluorescent phosphine products. Hydrophosphination of the fluorescent phosphine produces products with a complete selectivity for the secondary product. A key intermediate in catalysis, a zirconium phosphido compound, was isolated. Full article
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Open AccessArticle
The Trans Influence in Unsymmetrical Pincer Palladacycles: An Experimental and Computational Study
Inorganics 2016, 4(3), 25; doi:10.3390/inorganics4030025 -
Abstract
A library of unsymmetrical SCN pincer palladacycles, [ClPd{2-pyr-6-(RSCH2)C6H3}], R = Et, Pr, Ph, p-MePh, and p-MeOPh, pyr = pyridine, has been synthesized via C–H bond activation, and used, along with PCN and N’CN unsymmetrical pincer
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A library of unsymmetrical SCN pincer palladacycles, [ClPd{2-pyr-6-(RSCH2)C6H3}], R = Et, Pr, Ph, p-MePh, and p-MeOPh, pyr = pyridine, has been synthesized via C–H bond activation, and used, along with PCN and N’CN unsymmetrical pincer palladacycles previously synthesized by the authors, to determine the extent to which the trans influence is exhibited in unsymmetrical pincer palladacycles. The trans influence is quantified by analysis of structural changes in the X-ray crystal and density functional theory (DFT) optimized structures and a topological analysis of the electron density using quantum theory of atoms in molecules (QTAIM) to determine the strength of the Pd-donor atom interaction. It is found that the trans influence is controlled by the nature of the donor atom and although the substituents on the donor-ligand affect the Pd-donor atom interaction through the varied electronic and steric constraints, they do not influence the bonding of the ligand trans to it. The data indicate that the strength of the trans influence is P > S > N. Furthermore, the synthetic route to the family of SCN pincer palladacycles presented demonstrates the potential of late stage derivitization for the effective synthesis of ligands towards unsymmetrical pincer palladacycles. Full article
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Open AccessArticle
Mesoporous WN/WO3-Composite Nanosheets for the Chemiresistive Detection of NO2 at Room Temperature
Inorganics 2016, 4(3), 24; doi:10.3390/inorganics4030024 -
Abstract
Composite materials, which can optimally use the advantages of different materials, have been studied extensively. Herein, hybrid tungsten nitride and oxide (WN/WO3) composites were prepared through a simple aqueous solution route followed by nitriding in NH3, for application as
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Composite materials, which can optimally use the advantages of different materials, have been studied extensively. Herein, hybrid tungsten nitride and oxide (WN/WO3) composites were prepared through a simple aqueous solution route followed by nitriding in NH3, for application as novel sensing materials. We found that the introduction of WN can improve the electrical properties of the composites, thus improving the gas sensing properties of the composites when compared with bare WO3. The highest sensing response was up to 21.3 for 100 ppb NO2 with a fast response time of ~50 s at room temperature, and the low detection limit was 1.28 ppb, which is far below the level that is immediately dangerous to life or health (IDLH) values (NO2: 20 ppm) defined by the U.S. National Institute for Occupational Safety and Health (NIOSH). In addition, the composites successfully lower the optimum temperature of WO3 from 300 °C to room temperature, and the composites-based sensor presents good long-term stability for NO2 of 100 ppb. Furthermore, a possible sensing mechanism is proposed. Full article
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Open AccessReview
Anion Ordering in Bichalcogenides
Inorganics 2016, 4(3), 23; doi:10.3390/inorganics4030023 -
Abstract
This review contains recent developments and new insights in the research on inorganic, crystalline compounds with two different chalcogenide ions (bichalcogenides). Anion ordering is used as a parameter to form structural dimensionalities as well as local- and global-electric polarities. The reason for the
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This review contains recent developments and new insights in the research on inorganic, crystalline compounds with two different chalcogenide ions (bichalcogenides). Anion ordering is used as a parameter to form structural dimensionalities as well as local- and global-electric polarities. The reason for the electric polarity is that, in the heterogeneous bichalcogenide lattice, the individual bond-lengths between cations and anions are different from those in a homogeneous anion lattice. It is also shown that heteroleptic tetrahedral and octahedral coordinations offer a multitude of new crystal fields and coordinations for involved cations. This coordination diversity in bichalcogenides seems to be one way to surpass electro-chemical redox potentials: three oxidation states of a single transition metal can be stabilized, e.g., Ba15V12S34O3. A new type of disproportionation, related to coordination, is presented and results from chemical pressure on the bichalcogenide lattices of (La,Ce)CrS2O, transforming doubly [CrS3/3S2/2O1/1]3− (5+1) into singly [CrS4/2S2/3]7/3− (6+0) and [CrS4/3O2/1]11/3− (4+2) coordinations. Also, magnetic anisotropy is imposed by the anion ordering in BaCoSO, where magnetic interactions via S or O occur along two different crystallographic directions. Further, the potential of the anion lattice is discussed as a parameter for future materials design. Full article
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Open AccessArticle
Mesoporous C/CrN and C/VN Nanocomposites Obtained by One-Pot Soft-Templating Process
Inorganics 2016, 4(3), 22; doi:10.3390/inorganics4030022 -
Abstract
Nanocomposites of ordered mesoporous carbon associated with chromium nitride (CrN) or vanadium nitride (VN) nanoparticles were obtained by a simple one-pot synthesis based on the solvent evaporation induced self-assembly (EISA) process using Pluronic triblock surfactant as soft-template and a phenol-based resin (resol) as
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Nanocomposites of ordered mesoporous carbon associated with chromium nitride (CrN) or vanadium nitride (VN) nanoparticles were obtained by a simple one-pot synthesis based on the solvent evaporation induced self-assembly (EISA) process using Pluronic triblock surfactant as soft-template and a phenol-based resin (resol) as carbon precursor. These nanocomposites were characterized by X-ray diffraction, nitrogen physisorption and Transmission Electron Microscopy (TEM) techniques. Electron tomography (or 3D-TEM) technique was particularly useful for providing direct insight on the internal architecture of C/CrN nanocomposite. Nanocomposites showed a very well organized hexagonal mesoporous carbon structure and a relatively high concentration of nanoparticles well distributed in the porous network. The chromium and vanadium nitrides/mesoporous carbon nanocomposites could have many potential applications in catalysis, Li-ion batteries, and supercapacitors. Full article
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Open AccessArticle
Silylation of Dinitrogen Catalyzed by Hydridodinitrogentris(Triphenylphosphine)Cobalt(I)
Inorganics 2016, 4(3), 21; doi:10.3390/inorganics4030021 -
Abstract
Recently, homogeneous cobalt systems were reported to catalyze the reductive silylation of dinitrogen. In this study the investigations on the silylation of dinitrogen catalyzed by CoH(PPh3)3N2 are presented. We show that in the presence of the title compound,
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Recently, homogeneous cobalt systems were reported to catalyze the reductive silylation of dinitrogen. In this study the investigations on the silylation of dinitrogen catalyzed by CoH(PPh3)3N2 are presented. We show that in the presence of the title compound, the reaction of N2 with trimethylsilylchloride and sodium yields, on average, 6.7 equivalents of tris(trimethylsilyl)amine per Co atom in THF (tetrahydrofuran). The aim was to elucidate whether the active catalyst is: (a) the [Co(PPh3)3N2] anion formed after two-electron reduction of the title compound; or (b) a species formed via decomposition of CoH(PPh3)3N2 in the presence of the highly reactive substrates. Time profile, and IR and EPR spectroscopic investigations show instability of the pre-catalyst under the applied conditions which suggests that the catalytically active species is formed through in situ modification of the pre-catalyst. Full article
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