Discrete Anions Research Articles

Subtly tuning one N site of benzyl-1H-triazole ligands to build mono-nuclear subunits and tri-nuclear clusters to modify polyoxometalates

By using two kinds of organic ligands (1-benzyl-1H-(1,2,4)triazole (2-btz) and 1-benzyl-1H-(1,3,4)triazole (3-btz)), six polyoxometalate (POM)-based compounds were hydrothermally synthesized and structurally characterized, [Ag4(2-btz)4(HPMo2VMo10VIO40)] (1), [Ag4(2-btz)4(SiW12O40)] (2), [Ag4(2-btz)5K(SiWVW11VIO40)]·13H2O (3), [Cu4(2-btz)16(Mo8O26)2] (4), [Cu3(3-btz)8(H2O)4](PMo12O40)2·4H2O (5) and [Cu7(3-btz)16(OH)2(H2O)4(P2W18O62)2]·16H2O (6). Compounds 1 and 2 are isostructural with two sets of Ag–(2-btz) chains linked by Keggin anions to construct a “ladder”. Adjacent “ladders” are further connected by Ag1–O13 bonds to build a 3D framework. In compound 3, the anion dimers are linked by Ag5–O9 bonds to form a 1D chain. The chains are fused by Ag3 and K ions and a 3D framework of 3 is built. In compound 4, the Mo8 anions are linked by [Cu(2-btz)4]2+ subunits to construct a 3D structure. By changing 2-btz to 3-btz, we obtained a linear tri-nuclear cluster [Cu3(3-btz)8(H2O)4]6+ in compound 5. The discrete PMo12 anions combine with tri-nuclear clusters through hydrogen bonding interactions to construct a 2D supramolecular layer. Compound 6 contains a cycle tri-nuclear cluster-supporting anion [Cu3(3-btz)6(OH)(H2O)2(P2W18O62)]−, which is further connected by one [Cu(3-btz)4]2+ subunit to construct a discrete anion dimer. The title compounds show good electrocatalytic activities for reducing nitrite, hydrogen peroxide and bromate. These compounds also exhibit excellent photocatalytic activities for the degradation of methylene blue (MB, 1–6 as catalysts) and Rhodamine B (RhB, 5 and 6 as catalysts). Additionally, the magnetic properties of compounds 5 and 6 have been investigated.

Charge transfer from cobaltammine complex cations to metal fluoride anions in molecular solids with novel photoelectronic effects (metal: zirconium, titanium).

[Co(en)3](Ti2F11) containing H-bonded assembly of a discrete cobaltammine complex cation and titanium fluoride anion was successfully synthesized under solvothermal conditions. A novel photoelectronic effect was observed in the near-UV region. By extending our understanding of this compound, taking into account our previously reported three cobalt complex-containing zirconium fluorides, the mechanism of photoelectronic effects from these molecular solids was determined by investigating the relative work function for their component species with the help of a Scanning Kelvin probe. The results suggest that the charge transfer from the excited cobaltammine complex cations to the metal fluoride anions as a result of the cooperative behaviors might occur upon illumination, which is responsible for these novel photoelectronic effects.

Two New Organic‐Inorganic Hybrid Compounds using Bi‐ and Mono‐Nuclear Cu‐H2biim Subunits to modify Keggin Anions

Abstract Two new Keggin‐based organic‐inorganic hybrid compounds, namely [Cu8(H2biim)8(SiW12O40)2]·7H2O (1) and [Cu2(H2biim)4(H2O)2(SiMo12O40)] (2) (H2biim = 2,2′‐biimidazole), were hydrothermally synthesized by using the bi‐imidazole ligand and Keggin anions, and characterized by single‐crystal X‐ray diffraction, elemental analyses, IR spectra, and cyclic voltammetry. In compound 1, two H2biim ligands are fused by two Cu+ ions to form a dinuclear [Cu2(H2biim)2]4+ subunit. The Cu3‐based dinuclear subunits are further connected by [SiW12O40]4– anions to construct a 1D chain. The other Cu1‐based dimer acts as a supporting unit of the anion. Through changing [SiW12O40]4– to [SiMo12O40]4–, compound 2 was obtained, including discrete anions and mononuclear subunits [Cu(H2biim)2(H2O)]2+. The electrochemical behaviors of compounds 1 and 2 bulk‐modified carbon paste electrodes (1‐ and 2‐CPE) were studied.

Identification of mixed bromidochloridotellurate anions in disordered crystal structures of (bdmim)2[TeX2Y4] (X, Y = Br, Cl; bdmim = 1-butyl-2,3-dimethylimidazolium) by combined application of Raman spectroscopy and solid-state DFT calculations

The discrete mixed [TeBrxCl6−x]2− anions in their disordered crystal structures have been identified by using the phases prepared by the reaction of 1-butyl-2,3-dimethylimidazolium halogenides (bdmim)X with tellurium tetrahalogenides TeX4 (X=Cl, Br) as examples. Homoleptic (bdmim)2[TeX6] [X=Cl (1), Br (2)] and mixed (bdmim)2[TeBr2Cl4] (3), and (bdmim)2[TeBr4Cl2] (4) are formed depending on the choice of the reagents, and their crystal structures have been determined by single-crystal X-ray diffraction. The coordination environments of tellurium in all hexahalogenidotellurates are almost octahedral. Because of the crystallographic disorder, the mixed [TeBr2Cl4]2− and [TeBr4Cl2]2− anions in 3 and 4 cannot be identified in their crystal structures. Pawley refinement of the X-ray powder diffraction patterns of 1–4 indicates the presence of single phases in all four products. The solid state Raman spectra of 1–4 were assigned with help of DFT calculations that were performed both for the discrete anions in vacuum and for the complete crystal structures employing periodic boundary conditions. The fundamental vibrations of the homoleptic [TeX6]2− (X=Cl, Br) anions could be well reproduced by the solid-state DFT computations and enabled a complete assignment of the Raman spectra. While the presence of cis-isomers in both [TeBr2Cl4]2− and [TeBr4Cl2]2− could be inferred by the computed fundamental vibrations, that of trans-isomers among the reaction products is, however, also possible. The pathway of the formation of [TeX4Y2]2− isomers from TeX4 and Y− (X, Y=Cl, Br) was also explored by DFT calculations both in vacuum and in solution and indicated that both reactions afforded 80mol% of cis-isomers and 20mol% of trans-isomers.

Clusters [Co(As3S3)2]2–, [Ni(As3S3)2]2–, and [{Co(en)}6(μ3-S)4(AsS3)4]2– with Co–As or Ni–As Bonds: Solvothermal Syntheses and Characterizations of Thioarsenates Containing Transition-Metal Complexes

Solvothermal reactions of As2O3 and S with CoCl2·6H2O or NiCl2·6H2O in an aqueous solution of dien produced novel thioarsenates [Co(dien)2][Co(As3S3)2] (1) and [Ni(dien)2][Ni(As3S3)2] (2) (dien = diethylenetriamine), and the reaction with CoCl2·6H2O in an aqueous solution of en afforded complex [Hen]2[{Co(en)}6(μ3-S)4(AsS3)4] (3) (en = ethylenediamine). In 1 and 2, one transition-metal ion is coordinated by two dien ligands to form [TM(dien)2](2+) (TM = Co, Ni) complex cations. The As3S3 unit coordinates to the other TM(II) ion with both As- and S-donor atoms to form the [TM(As3S3)2](2-) anionic cluster, in which TMAs2, TMAs2S2, and TMAs3S2 rings are formed. In 3, each Co(3+) ion is coordinated by an en ligand. Six Co(en) units are interlinked by four μ3-S and four AsS3 ligands to form a [{Co(en)}6(μ3-S)4(AsS3)4](2-) cluster containing an adamantane-like Co6S4 core. The AsS3 unit coordinates to Co atom in the η(1)-As1,η(2)-S coordination mode with As binding Co(1) and S(1) binding Co(1) and Co(2). The As3S3 and AsS3 ligands with both As- and S-donor atoms in 1-3 have never been obtained in amine solution before. The same reactions in pure dien and en solvents afforded compounds [Co(dien)2]3[As3S6]2 (4) and [Co(en)3]2As2S5 (5) containing discrete anions [As3S6](3-) and [As2S5](4-), respectively. The band gaps of 1-3 are in the range of 1.37-1.55 eV, and the band gaps of 4 and 5 are 2.24 and 2.26 eV, which show the influence of the coordination mode of thioarsenate ligands on the electronic transitions in the TM-thioarsenates.

Synthesis, Crystal Structure, and Characterization of a New Organic-Inorganic Hybrid Material:

The title compound is an organic-inorganic hybrid material. The single crystal X-ray diffraction investigation reveals that the studied compound crystallizes in the orthorhombic system, space group Pbca with the following lattice parameters: (4) Å, (3) Å, (6) Å, and . The crystal lattice is composed of a discrete anion surrounded by piperazinium cations, chlorine anions, and water molecules. Complex hydrogen bonding interactions between , , organic cations, and water molecules form a three-dimensional network. Room temperature IR, Raman spectroscopy, and optical absorption of the title compound were recorded and analysed. The observed crystal morphology was compared to the simulated one using the Bravais-Friedel, Donnay-Harker model.

Erratum to: Electrochemical dissolution of metallic platinum in ionic liquids

The electrochemical dissolution of Pt in several ionic liquids (ILs) was studied. Different ILs were tested assessing their potential to dissolve Pt. Dissolution rate and current efficiency were evaluated. The main focus was on Cl containing ILs: first generation, eutectic-based ILs and second generation ILs with discrete anions. Pt dissolution only occurred in type 1 eutectic-based ILs with a max. dissolution rate of 192.2 g m−2 h−1 and a max. current efficiency of 99 % for the ZnCl2–1-ethyl-3-methylimidazolium chloride IL, and 9.090 g m−2 h−1 and 96 % for the 1:1 ZnCl2–choline chloride IL. The dissolution occurred through the formation of [PtClx]y− complexes. To form these complexes, addition of a metal chloride was necessary. Furthermore, an IL with an electrochemical window of 1.5 V, preferably 2.0 V was required to achieve Pt dissolution. The added metal salt needed to have a higher decomposition potential than 1.5 V or should be a Pt salt.

Anionic lanthanide complexes with 3-methyl-4-formyl-1-phenyl-5-pyrazolone

The coordination compounds Na[LnL4] · 2H2O and [NBu4][LnL4] (Ln = Nd, Sm, Eu, Tb; HL is 3-methyl-4-formyl-1-phenyl-5-pyrazolone) have been synthesized and studied by IR spectroscopy and thermogravimetry. According to X-ray diffraction data, the coordination polyhedra of lanthanides are shaped as square antiprisms and formed by the oxygen atoms of four deprotonated moieties of the enol form of 4-formyl-5-pyrazolone. In the complex Na[EuL4] · 2H2O, sodium cations are bonded to the two nitrogen atoms of pyrazole heterocycles, combining discrete complex anions into two interpenetrating three-dimensional frameworks. Polycrystalline samples of neodymium(III), samarium(III), and terbium(III) complexes manifest intense luminescence in the spectral regions that are typical for them.

Structural aspects of blast furnace slag

Interdependence of structure and viscosity of blast furnace slag is discussed based on the available literature. Emphasis is given to both, bridging tendency and network breaking/modifying tendency of the constituents. It is clearly pointed out that slag viscosity cannot be explained only by depolymerization through an increase in basicity, despite the fact that an increase in basicity of the slag, in general, lowers the viscosity of the slag by a process of generation of discrete anions containing simple chains and/or rings by causing depolymerization of the 3D silicate network.

Structure–Property Relationship of CaO-MgO-SiO2 Slag: Quantitative Analysis of Raman Spectra

The quantitative structural information such as the relative abundance of silicate discrete anions (Q n units) and the concentration of three types of oxygens, viz. free-, bridging- and nonbridging oxygen can be obtained from micro-Raman spectra of the quenched CaO-SiO2-MgO glass samples. Various transport properties such as viscosity, density, and electrical conductivity can be expected as a simple linear function of “ln (Q3/Q2),” indicating that these physical properties are strongly dependent on a degree of polymerization of silicate melts. The methodology outlined in the current study can be extended to predict the physicochemical properties of silicate melts in ferrous and non-ferrous metallurgical processes.

Electrochemical dissolution of metallic platinum in ionic liquids

The electrochemical dissolution of Pt in several ionic liquids (IL’s) was studied. Different IL’s were tested assessing their potential to dissolve Pt. Dissolution rate and current efficiency were evaluated. The main focus was on Cl containing IL’s: first generation, eutectic based IL’s and second generation IL’s with discrete anions. Pt dissolution only occurred in type 1 eutectic-based IL’s with a max. dissolution rate of 192.2 g m−2 h−1 and a max. current efficiency of 99 % for the ZnCl2-1-ethyl-3-methylimidazolium chloride IL, and 9.090 g m−2 h−1 and 96 % for the 1:1 ZnCl2–choline chloride ionic liquid. The dissolution occurred via the formation of [PtCl x ] y− complexes. To form these complexes, addition of a metal chloride was necessary. Furthermore, an IL with an electrochemical window of 1.5 V, preferably 2.0 V is required to achieve Pt dissolution. The added metal salt needed to have a higher decomposition potential than 1.5 V or should be a Pt salt.

Lead(ii) chloride ionic liquids and organic/inorganic hybrid materials – a study of chloroplumbate(ii) speciation

A range of chloroplumbate(II) organic salts, based on the two cations, 1-ethyl-3-methylimidazolium and trihexyl(tetradecyl)phosphonium, was prepared by ionothermal synthesis. Depending on the structure of the organic cation and on the molar ratio of PbCl2 in the product, χPbCl2, the salts were room-temperature ionic liquids or crystalline organic/inorganic hybrid materials. The solids were studied using Raman spectroscopy; the crystal structure of [C2mim]{PbCl3} was determined and shown to contain 1D infinite chloroplumbate(II) strands formed by edge-sharing tetragonal pyramids of pentacoordinate (PbCl5) units. The liquids were analysed using (207)Pb NMR and Raman spectroscopies, as well as viscometry. Phase diagrams were constructed based on differential scanning calorimetry (DSC) measurements. Discrete anions: [PbCl4](2-) and [PbCl3](-), were detected in the liquid state. The trichloroplumbate(II) anion was shown to have a flexible structure due to the presence of a stereochemically-active lone pair. The relationship between the liquid phase anionic speciation and the structure of the corresponding crystalline products of ionothermal syntheses was discussed, and the data were compared with analogous tin(II) systems.

Electrodeposition of some metals and their alloys using different deep eutectic solvents based on choline chloride

Ionic liquids with discrete anions are deep eutectic solvents can be utilized for metals electroplating. In this investigation various types of deep eutectic solvents have been utilized such as Reline, Ethaline and Hybrid as solvents for the electrodeposition of Sn, Zn and Zn-Sn alloys. Ethaline and Reline displayed identical voltammetric profiles for the reduction of Zn+2 and Sn+2. Reline possess high viscosity which lead to decreasing the quality of electroplating, therefore the process needs higher temperature or longer electroplating time. The surface morphology and compositions have been characterized using scanning electron microscopy (SEM) and elemental analysis by energy dispersive X-ray Spectroscopy (EDX). These techniques lead to detecting the metal alloy that have been added to the ionic liquids. Pure ionic liquids preparation was another aim of this investigation, which utilized as a standard scale for comparison with the metal based liquids. Analysis of cyclic voltammetry in all systems indicated differences in the reactivity and mobility of species in solution which affected the growth mechanism and resulted in changes in deposit morphology. Keywords

The ionic liquid 1-alkyl-3-methylimidazolium demonstrates comparable antimicrobial and antibiofilm behavior to a cationic surfactant

Biofilms are problematic in health and industry because they are resistant to various antimicrobial treatments. Ionic liquids are a novel class of low temperature liquid salts consisting of discrete anions and cations, and have attracted considerable interest as safer alternatives to organic solvents. Ionic liquids have interesting antimicrobial properties and some could find use in the development of novel antiseptics, biocides and antifouling agents. The antimicrobial and antibiofilm activity of 1-dodecyl-3-methylimiazolium iodide ([C12MIM]I) was studied using the clinically important bacterial pathogens, Staphylococcus aureus SAV329 and Pseudomonas aeruginosa PAO1. The ionic liquid increased cell membrane permeability in both S. aureus and P. aeruginosa cells and impaired their growth, attachment and biofilm development. The ionic liquid exhibited superior antimicrobial and antibiofilm activity against the Gram-positive S. aureus compared to the Gram-negative P. aeruginosa cells. BacLight™ staining and confocal microscope imaging confirmed that the ionic liquid treatment increased the cell membrane permeability of both the Gram-positive and Gram-negative bacteria. In addition, the antimicrobial and antibiofilm properties of [C12MIM]I were similar or superior to those of cetyltrimethylammonium bromide (CTAB), a well-known cationic surfactant. It is concluded that the ionic liquid induced damage to bacterial cells by disrupting cell membrane, leading to inhibition of growth and biofilm formation. Overall, the results indicate that the ionic liquid 1-dodecyl-3-methylimiazolium iodide was effective in preventing S. aureus and P. aeruginosa biofilms and could have applications in the control of bacterial biofilms.

Sodium pentafluorophenylborate

The crystal structure of the title compound, Na[(C6F5)BH3], is composed of discrete anions and cations. The sodium cations are surrounded by four anions with three short Na⋯B [2.848 (8), 2.842 (7) and 2.868 (8) Å] and two short Na⋯F contacts [2.348 (5) and 2.392 (5) Å], forming a three-dimensional network. The anion is the first structural example of a pentafluorophenyl ring carrying a BH3 group.

Magneto‐Structural Study of an Oxamato‐Bridged PdIICoII Chain: X‐ray Crystallographic Evidence of a Single‐Crystal‐to‐Single‐Crystal Phase Transition

AbstractTwo new mononuclear oxamato‐containing palladium(II) complexes of formula K2[Pd(opba)]·2H2O (1) and (PPh4)2[Pd(opba)]·2H2O (2) and the heterodimetallic palladium(II)–cobalt(II) chain {[Co(H2O)2Pd(opba)]·dmso}n (3) [opba = 1,2‐phenylenebis(oxamate), PPh4+ = tetraphenylphosphonium cation and dmso = dimethyl sulfoxide] have been prepared, and the structures of two of them (compounds 2 and 3) were determined by X‐ray diffraction analysis of single crystals. The structure of 2 consists of discrete anions of [Pd(opba)2]2– and PPh4+ cations. Each PdII ion in 2 is surrounded by two oxamate nitrogen atoms and two carboxylate oxygen atoms in a square‐planar surrounding. Compound 3 is a neutral chain with regular alternating PdII and CoII ions, the [Pd(opba)]2– entity acting as a bis(bidentate) ligand towards trans‐diaquacobalt(II) fragments, and dmso molecules of crystallization. Compound 3 exhibits a single‐crystal‐to‐single‐crystal phase transition between monoclinic C2/c (α phase) and triclinic P$\bar {1}$ (β phase) space groups. Within the α phase the dmso molecule of crystallization is disordered, but it becomes ordered below 215 K in the β phase. The ordering process of the dmso molecule is followed by a reduction in the unit cell volume. The magnetic properties of 3 are barely affected by the structural phase transition, and they indicate an important spin–orbit coupling of the high‐spin octahedral CoII ion [α = 1.245, λ = –151 cm–1, Δ = 494 cm–1, the spin Hamiltonian being defined as H = –αλLS + Δ(Lz2–2/3) + βH(–αL + geS)] with an almost negligible intra‐ [through the diamagnetic square‐planar PdII centre] and interchain antiferromagnetic interactions (θ = –0.32 K).

Three Novel Metal Supramolecular Polymers Directed by 1,2-bis(pyridinium)ethane Cation: Syntheses and Crystal Structures

Three novel supramolecular polymers, [(Cd2Cl3)(H2O)2(N3)3 (bpe)] (bpe = 1,2-bis(pyridinium)ethane)(1), [(ZnCl4)(bpe) (ZnCl3N3)(bpe)](2), and [(CdCl2Br2)(bpe)] (3), were synthesized in polar organic solvents using solvent diffusion method, and the three compounds have been characterized by single-crystal X-ray diffraction and IR spectroscopy. Compound 1 comprises discrete bpe cations and centrosymmetric tetrameric anions in which cadmium(II) centers have two distinct coordination modes (four- and six-coordinated) bridged by end-on azide. The three-dimensional (3-D) organic–inorganic hybrid supramolecular structure is formed by a series of hydrogen bonds (O-H···Cl and O-H···N). Compared with compound 1, the reactants of complex 2 also include sodium azide, bpe2+ and transition metal salt except that ZnCl2 instead of CdCl2, but compound 2 is only a mononuclear complex with two different tetrahedral configuration of Zn centers. The mononuclear compound 3 crystallizes in orthorhombic system with the space group Pnma, and the Cd(I) atom is four-coordinated in a distorted tetrahedral geometry by two terminal Cl and two terminal Br.

Propane-1,3-diammonium dichromate(VI)

The title compound, (C3H12N2)[Cr2O7], consists of a discrete dichromate anion with an eclipsed conformation and a propane-1,3-diammonium cation. Both kinds of ions have a mirror plane passing through the bridging O atom and the central methyl­ene C atom of the Cr2O7 2− and C3H12N2 2+ moieties, respectively. Anions and cations are alternately stacked to form columns parallel to the b axis. Ions are linked by intra- and inter-column hydrogen bonds of types N—H⋯O and C—H⋯O, involving O atoms of the dichromate anions as acceptors, and ammonium or methyl­ene groups as donors.

Synthesis and Crystal Structure of a Binuclear Manganese(II) Ternary Complex Derived From N-(2- pyridylmethylidene)taurine and 1,10-Phenanthroline

The title compound, 1, with the formula [Mn2(pmt)2(1,10-phen)2].2ClO4 [N-(2-pyridylmethylidene)taurine (abbreviated as pmt), consists of a structurally centrosymmetric dinuclear MnII complex and two discrete perchlorate anions. Each Mn center is six-coordinated with an N4O2 donors set of the pmt and 1,10-phenanthorline ligands, resulting in a compressed octahedral. In the crystal packing, the component cations interact with pairs of intermolecular C-H···O and π-π contacts forming a 2-D network. Also, the neighboring 2-D cationic layers are connected to each other with C–H···O interactions of perchlorate oxygen atoms with the separate C···O distances of 3.204(7)-3.365(8) Å, giving a supramolecular 3-D network. [Supplemental materials are available for this article. Go to the publisher's online edition of Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry to view the supplemental file.]

Convenient Route to Alkylene Dithiophosphato Ligands: Synthesis and Crystallographic Analysis of [OCH2CMe2CH2OPS2HNEt3

Triethylammonium salts of O,O′-alkylene dithiophosphato like OGOPS2HNEt3, [where, G = –CH2CMe2CH2–(1), –CH2CEt2CH2–(2), –CMe2CH2CHMe–(3) and –CMe2CMe2–(4)] have been synthesized in quantitative yield by the direct reaction of P2S5 with 1,2- and 1,3-substituted glycols in presence of triethylamine, Et3N, in 1:2:2 molar stoichiometry in toluene. These have been mainly characterized by molecular weight, IR and NMR (1H, 13C and 31P) spectroscopic studies. Single crystal X-ray structure analysis of [OCH2CMe2CH2OPS2HNEt3] reveals that phosphorus atom is tetrahedrally bonded to two sulfur atoms and two oxygen atoms in the ring and the molecule exists as discrete cation and anion. The structure is stabilized by cation–anion N–H···S hydrogen bonded interactions. Antiparallel pattern of triethylammonium ion is sandwiched within the two-dimensional layers of the ring system. Crystallographic analysis of [OCH2CMe2CH2OPS2HNEt3] reveals that phosphorus atom is tetrahedrally bonded to two sulfur atoms and two oxygen atoms in the ring and the molecule exists as discrete cation and anion. The structure is stabilized by cation-anion N-H···S hydrogen bonded interactions. Antiparallel pattern of triethylammonium ion is sandwiched within the two-dimensional layers of the ring system.