Complex Salt Research Articles

Nickel(II) Cyanoborates and Cyanoborate-Ligated Nickel(II) Complexes.

Nickel(II) cyanoborates Ni[BH2(CN)2]2·H2O (1b·H2O), Ni[BH(CN)3]2·0.5H2O (1c·0.5H2O), and Ni[B(CN)4]2·0.5H2O (1d·0.5H2O) were synthesized, and their reactivity with respect to dppeO2 (=1,2-bis-(diphenylphosphinoethane dioxide)), pyNO (=pyridine-N-oxide), dppe (=1,2-bis-(diphenylphosphinoethane), and DMSO (=dimethyl sulfoxide) was examined. Using these ligands, either cyanoborate (CB) complex salts of [Ni(dppe)2]2+ (2b-d) and [Ni(pyNO)6]2+ (3c-d) were isolated or complexes [Ni(DMSO)4{NC-B(CN)3}2] (1dDMSO) and [Ni(dppeO2)2{NC-B(CN)3}2] (1ddppeO2) were formed. Salt metathesis of [Ni(dppe)Cl2] with alkali metal cyanoborates resulted in mono- and disubstituted coordination compounds [Ni(dppe){NC-BH(CN)2}Cl] (5c) and [Ni(dppe){NC-BH2CN)2}] (4b), which decomposed to salts 2b-d. The synthetical pathways explored offer convenient routes to nickel(II) cyanoborates, nickel(II) complexes ligated with cyanoborates, and nickel(II) complex salts of cyanoborates. Further, our studies demonstrate the diverse character of cyanoborates in coordination chemistry as noncoordinating counteranions and also as medium coordinating anions forming novel transition-metal complexes and salts.

Enhanced removal of iron from iron-rich manganese ore leaching solution: A promising strategy by seed-induced

Enhanced removal of iron from iron-rich manganese ore leaching solution has become a bottleneck limiting the development of the electrolytic manganese industry. Herein, iron-rich electrolytic manganese residue (IREMR) as a seeding to enhance iron removal. The results showed that the iron removal efficiency was 99.97 % with only manganese loss of 1.5 % whenadding 1 g/L IREMR. Compared with the traditional conditions of electrolytic metal manganese enterprise, it demonstrated several environmental advantages: lower manganese loss (from 16 % to 1.5 %), less IREMR produced (64.45 %), faster filtration speed (from 0.0013 to 0.1966 mL/s.cm2). Based on multiphase equilibria modelling and strengthening mechanism analysis, enhanced iron removal by seed-induced can reduce the formation of ammonium-alum complex salts and prevent the formation of Fe(OH)3 colloid. In addition, IREMR as seeding applied in the iron removal process can accelerate the formation of goethite and hematite to shorten the nucleation cycle. This strategy is important for source reduction and resource utilization of electrolytic manganese residue.

Fractional precipitation of Ni and Co double salts from lithium-ion battery leachates

The isolation of Ni/Co double salts can be recovered by fractional precipitation with ammonium sulfate. The elemental analysis of these isolated double salts shows a total metal composition of >99% of Ni, Co, and Mn with negligible impurity metals.

Preparation, and antibacterial activity of chitosan derivative containing double quaternary ammonium salt and hydantoin structures

Chitosan quaternary ammonium salt antibacterial agents with a single structure have the drawbacks of slow bactericidal speed and poor bactericidal effect, which cannot meet the practical usage requirements. To address the problem, in this study, we designed and synthesized a novel chitosan derivative containing double quaternary ammonium salt and chloride hydantoin structures (QCS-CA-DEADH-Cl) by using chitosan, 5,5-dimethyl hydantoin, methyl iodide, and 2-Dimethylaminoethyl chloride hydrochloride as the main raw materials, and then used as antibacterial agent. The structure of QCS-CA-DEADH-Cl was characterized by Fourier transform infrared spectra, X-ray photoelectron spectroscopy, Thermogravimetric, and Scanning electron microscopy. The antibacterial activity of QCS-CA-DEADH-Cl, and the renewability and stability of N-Cl structure in QCS-CA-DEADH-Cl were explored. The results indicated that the N-Cl structure of QCS-CA-DEADH-Cl has strong renewability and storage stability. Moreover, the synergistic effect of quaternary ammonium salt structure and N-Cl structure endowed QCS-CA-DEADH-Cl with excellent antibacterial activity. This work does not only provide a new perspective for the preparation of novel chitosan antibacterial agents but also contributes to expanding the comprehensive utilization of biomass resources.

Magnetic anisotropy and slow relaxation of magnetisation in double salts containing four- and six-coordinate cobalt(II) complex ions.

Four novel Co(II) coordination compounds 1-4 of the general formula [Co(Ln)2][Co(NCY)4]·mCH3CN (where Ln are tridentate ligands L1 = 2,6-bis(1-hexyl-1H-benzimidazol-2-yl)pyridine for 1 and 2; L2 = 2,6-bis(1-octyl-1H-benzimidazol-2-yl)pyridine for 3; L3 = 2,6-bis(1-dodecyl-1H-benzimidazol-2-yl)pyridine for 4, Y = O for 1, 3, and 4 and Y = S for 2; m = 0 for 1 and 3, m = 0.5 for 2 and m = 2 for 4) were prepared and characterised. The molecular structures of all four compounds consist of the hexacoordinate complex cation [Co(Ln)2]2+ and tetracoordinate complex anion [Co(NCY)4]2-, with distorted octahedral and tetrahedral symmetry of coordination polyhedra, respectively. The electronic structures of all compounds feature an orbitally non-degenerate ground state well-separated from the lowest excited state, which allows the analysis of the magnetic anisotropy by the spin Hamiltonian model. ZFS parameters, derived from both CASSCF-NEVPT2 calculations and magnetic data analysis, indicate that tetrahedral anions [Co(NCY)4]2- exhibit small axial parameters |D| spanning the range of 2.2 to 7.7 cm-1, while octahedral cations [Co(Ln)2]2+ display significantly larger |D| parameters in the range of 37 to 95 cm-1. For 1-3, the Fourier-transform infrared magnetic spectroscopy (FIRMS) revealed a reasonable transmission with a magnetic absorption around the expected value for the ZFS accompanied by features allowing to identify phonon frequencies and simulate spin-phonon couplings. Dynamic magnetic investigations unveiled the field-induced slow relaxation of magnetisation, with maximal relaxation times (τ) of 92(2) μs for 2 at 2 K and BDC = 0.3 T. The temperature evolution of τ was analysed using a combination of Orbach, direct and Raman relaxations (Ueff = 8(1) K (5.6 cm-1)) or Orbach, direct and spin-phonon induced relaxations (Ueff = 10.3(9) K (7.2 cm-1)). The rest of the complexes, namely 1, 3, and 4 show field-induced slow relaxation of magnetisation with τ smaller than 16 μs.

Double complex salts based on tetraamminplatinum(ii) and vanadyl(iv) bisoxalate for the preparation of bimetallic Pt–V alloys

Two novel heterometallic complex salts have been synthesized, systematically investigated, and used as precursors for the Pt0.6V0.4 alloy.

Humidity and temperature driven transformations in ferroelectric quinuclidine-based chlorocobaltate(ii) complex salt: bulk and thin films with preferred orientation

Due to soft crystal packing driven by non-covalent interactions 3-quinuclidinone cations and (CoCl4)2– anions self-assemble along the preferred crystallographic orientation and form homogeneous thin films with switchable ferroelectric properties.

NHC-ligated nickel(II) cyanoborate complexes and salts.

A comprehensive study on the synthesis and characterization of NHC-ligated nickel(II) cyanoborates (CBs) is presented (NHC = N-heterocyclic carbene). Nickel(II) cyanoborates Ni[BH2(CN)2]2·H2O (Ib·H2O), Ni[BH(CN)3]2·0.5H2O (Ic·0.5H2O), Ni[B(CN)4]2·H2O (Id·H2O) were reacted with selected NHCs of different steric size. The reaction of the nickel cyanoborates with small to medium-sized NHCs Me2ImMe and iPr2Im (R2Im = 1,3-di-organyl-imidazolin-2-ylidene; R2ImMe = 1,3-di-organyl-4,5-dimethyl-imidazolin-2-ylidene) afforded cyanoborate salts containing the rare homoleptic fourfold NHC-ligated nickel(II) cations [Ni(NHC)4]2+ (NHC = Me2ImMe (1c-d), iPr2Im (2c-d)) and cyanoborate counter-anions. Bulkier NHCs such as Mes2Im and Dipp2Im afforded complexes trans-[Ni(NHC)2(CB)2] (trans-4b, trans-5c). For the combination of the cyanoborate anion [BH2(CN)2]- and iPr2ImMe the salt of the tris-NHC complex [Ni(iPr2ImMe)3(NC-BH2CN)][BH2(CN)2] (3b) was isolated. Salt metathesis of NHC-ligated nickel(II) halides (Ni(NHC)2X2) (X = Cl, Br) with silver(I) and alkali metal cyanoborates were used to synthesize mono- and disubstituted coordination compounds of the type cis- or trans-[Ni(NHC)2(CB)X] (cis-10c, cis-11c, trans-12b) and cis- or trans-[Ni(NHC)2(CB)2] (cis-13b, cis-14a-c, trans-14a-b, trans-15b, trans-5b). Further investigations reveal that NHC-ligated cyanoborate complexes can act as building blocks for coordination polymers, as observed for structurally characterized 1∞{trans-[Ni(Mes2Im)2(μ2-[NC-BH2-CN])2]·2Ag(μ2-[BH2(CN)2])} (trans-5b·Ag). This study demonstrates the diverse character of cyanoborates in coordination chemistry as both, non-coordinating counter-anions, and weakly to medium coordinating anions forming novel transition metal complexes and salts. It provides evidence that a proper choice of cyanoborate and a proper choice of co-ligand can lead to a rich coordination chemistry of cyanoborate anions.

Rapid nucleation and optimal surface-ligand interaction stabilize wurtzite MnSe.

Non-native structures (NNS) differ in discrete translational symmetry from the bulk ground state native structure (NS). To explore the extent of deconvolution of various factors relevant to the stabilization of the wurtzite/NNS of MnSe via a heat-up method, we performed experiments using various ligands (oleic acid, oleylamine, octadecylamine, stearic acid, and octadecene), solvents (tetraethylene glycol and octadecene), and precursor salts (manganese chloride and manganese acetate). Experiments suggest that oleic acid in the presence of tetraethylene glycol and oleylamine in the presence of octadecene stabilize wurtzite/NNS. Further, density functional theory (DFT) computations explore the interaction between the functional groups in ligands and the most exposed surfaces of wurtzite/NNS and rocksalt/NS polymorphs. Computations suggest that the interactions between relevant surface facets with carboxylic acid and the double bond functional groups suppress the phase transformation from NNS to NS. In addition, the ionizability of the precursor salt also determines the rate of formation of the metal-ligand complex and the rate of nucleation. Consequently, the formation rate of the Mn-ligand complex is expected to be greater in the case of chloride salt than acetate salt because the chloride salt has higher ionizability in ethylene glycol. From the above, we conclude that the kinetics of the wurtzite/NNS to rocksalt/NS phase transformation depends mainly on two factors: (1) nucleation/growth kinetics which is controlled by the ionizability of the precursor salt, solvent, and stability of the metal-ligand complex, and (2) the activation energy barrier of the NNS to NS conversion which is controlled by surface energy minimization with the ligand.

Computational design of C-substituted paraquat/diquat derivatives for neutral aqueous organic redox flow batteries

Identifying optimal C-substituted quaternary bipyridinium derivatives for the anolyte materials of neutral aqueous organic redox flow batteries via DFT theoretical calculation approaches.

Extraction of Lithium from Magnesium-Rich Solution Using Double Metal Salts as Co Extraction Reagents

Extraction of Lithium from Magnesium-Rich Solution Using Double Metal Salts as Co Extraction Reagents

Oxalatocuprate(ii) hexaammincobalt(iii) as a precursor of metastable solid solutions in the Co–Cu system

The synthesis and characterization of the double complex salts [Co(NH3)6]2[Cu(C2O4)2]3·4H2O and [Co(NH3)6]2[Cu(C2O4)2]3·6H2O was carried out. Subsequent annealing led to the formation of metastable solid solutions.

Lanthanide complexes with a new luminescent iminophosphonamide ligand bearing phenylbenzothiazole substituents.

A new iminophosphonamine Ph2P(HNPbt)(NPbt) (1, HL) bearing chromophore 2-(phen-2'-yl)-1,3-benzothiazole (Pbt) substituents was synthesized and introduced into lanthanide complexes. It was found that salt metathesis reactions between KL (2) generated in situ and LnCl3 lead to the formation of tris-iminophosphonamide complexes [LnL2]L (Ln = Y (3), Sm (4), Gd (5), Dy (6)), regardless of the 2/LnCl3 ratio. Compounds 3-6 consist of a cationic fragment [LnL2]+, where the lanthanide atom is surrounded by two rigidly κ4-coordinated ligands, and an L- anion residing in the outer coordination sphere. Iminophosphonamine 1 shows a rare excitation wavelength-dependent two-band luminescence in the solid state. For compounds containing the deprotonated form, namely potassium salt KL and complexes of Gd and Dy, a single-band luminescence with the color changing from turquoise to orange was observed. The Sm complex reveals a set of a few narrow well-resolved bands corresponding to the f-f transitions against the background of the outer-sphere ligand's emission.

Thermodynamics of the Eu(III)-Mg-SO4-H2O and Eu(III)-Na-SO4-H2O systems. Part I: solubility experiments and the full dissociation Pitzer model.

The solubility of Eu(III) was investigated under undersaturated conditions in acidic, dilute to concentrated MgSO4 and Na2SO4 solutions at T = (22 ± 2) °C. After attaining equilibrium conditions, solid phases were characterized by a multi-method approach, including X-ray diffraction (XRD), Raman and infrared (IR) spectroscopy, quantitative chemical analysis (ICP-OES) and thermogravimetric analysis (TG-DTA). A total of 45 solubility samples were investigated for the systems Eu2(SO4)3-MgSO4-H2O (19 samples) and Eu2(SO4)3-Na2SO4-H2O (26 samples). Eu2(SO4)3·8H2O(cr) was found to control the solubility of Eu(III) in all investigated MgSO4 solutions, as well as in dilute Na2SO4 systems. The transformation of Eu2(SO4)3·8H2O(cr) into the double salt Na2Eu2(SO4)4·2H2O(cr) was observed at mNa2SO4 > 0.01 mol kg-1. The latter phase is characterized by significantly lower solubility. Based on these experimental solubility measurements, thermodynamic and activity models were proposed based on the Pitzer equations considering the full dissociation of the Eu(III) species in MgSO4 and Na2SO4 aqueous solutions, i.e. deliberately excluding Eu(III)-sulfate complex formation. A combination of the geochemical calculation code PhreeSCALE and the parameter estimation code PEST was used to determine the values of solubility products and binary and ternary specific interaction parameters (β(0)ij, β(1)ij, Cϕij, θik, Ψijk).

A new methodology for measuring the enthalpies of mixing and heat capacities of molten chloride salts using high temperature drop calorimetry.

Molten salt reactors (MSRs) are a promising alternative to conventional nuclear reactors as they may offer more efficient fuel utilization, lower waste generation, and improved safety. The state of knowledge of the properties of liquid salts is far from complete. In order to develop the MSR concept, it is essential to develop a fundamental understanding of the thermodynamic properties, including the heat capacities (Cp) and enthalpies of mixing (ΔHmix), of molten salts at MSR operating conditions. Historically, the Cp values of molten salts were determined by drop-calorimetry or differential scanning calorimetry, whereas their ΔHmix values were typically measured using specialized high temperature calorimeters. In this work, a new methodology for measuring both the Cp and the ΔHmix of molten chloride salts was developed. This novel method involves sealing a chloride salt sample in a nickel capsule and performing conventional transposed temperature drop calorimetry using a commercially available Setaram AlexSYS-800 Tian-Calvet twin microcalorimeter. This methodology may be applied to calorimetric measurements of more complex salt mixtures, especially mixtures containing actinides and fission products.

Access to ligand-stabilized PH-containing phosphenium complexes.

While the chemistry of phosphenium compounds, including metal complexes thereof, is very well established, few derivatives having a P-H bond have been described, yet. This work describes rational access to donor-stabilised phosphenium metal complexes possessing a P-H bond using protonation reactions of stable phosphinidene complex adducts. While most Brønsted-Lowry acids yield formal 1,1-addition products at the phosphorus centre under the loss of the donor, super-strong acids having weakly coordinating anions enable access to donor-stabilised P-H phosphenium complex salts. The latter possess N-methylimidazole as a donor (to phosphorus) and the N-P interaction has been studied theoretically.

Study of the bactericidal effect of dialkylamine complex salts of oleic acid on the vital activity of sulfate-reducing bacteria

Study of the bactericidal effect of dialkylamine complex salts of oleic acid on the vital activity of sulfate-reducing bacteria

Colour/luminescence changes of transition metal complexes induced by gaseous small molecules for monitoring reaction progress and environmental changes.

Transition metal complexes act as monitoring devices for reaction progress and environmental changes through their color/luminescence changes. In this paper, we focus on colour/luminescence changes induced by gaseous small molecules in the environment. The gradual decrease in O2 content in solution can be monitored by the luminescence enhancement of an Ir(III) complex in dimethyl sulfoxide during photoirradiation. CO2 in air can be captured by a Pt(II) complex in basic aqueous solution, resulting in a colour change from yellow to red to blue-green due to higher degree aggregate formation. Moisture in air induces colour/luminescence changes in Ru(II) and Ir(III) complex salts due to the sorption of H2O into hydrophilic channels in the crystal. Volatile organic compound vapours such as CHCl3 and CH2Cl2 change the purple colour of Pt(II) complex crystals to red and blue, respectively. The purple crystal can adsorb two CHCl3 molecules under ambient conditions but only one CH2Cl2 molecule.

Gold carbonyl cations and beyond: homoleptic gold(I) complexes with P4 and P4S3 and the half-sandwich cation [Au(C6H6)(CO)

Oxidation of Au0 with the synergistic Ag+/0.5 I2 system in the commercial organic solvent 1,2,3,4-tetrafluorobenzene led to the perfluoroalkoxyaluminate salt of the [Au(CO)2]+ cation known from superacid chemistry. This [Au(CO)2]+ salt proved to be an excellent 'naked' Au+-synthon yielding complex salts with [Au(η2-P4)2]+, [Au(η1-P4S3)2]+ and half-sandwich [Au(η2-C6H6)(CO)]+ cation.

Exploring structural and optical properties of a new series of soft salts based on cyclometalated platinum complexes.

A series of nine new soft salts based on two platinum(II) complexes, namely ([Pt(C^N)(CN)2]-[Pt(C^N)(en)]+) (en = ethane-1,2-diamine), has been developed and synthesized. Their photophysical properties in both solution and the solid state were described. All soft salt complexes exhibit phosphorescence emission with PLQY in the solid state up to 0.36. Most of these materials displayed aggregation-induced emission (AIE) or aggregation-induced emission enhancement (AIEE) in water/DMSO solutions as the water ratio increased. Structure-property relationships were analyzed in relation to emission properties. The presence of the free nitrogen atoms in soft salt complexes with a C^N pyrimidine-based ligand allowed for reversible sensitivity to acidic vapors, resulting in the quenching of phosphorescence emission. Additionally, for selected soft salts, we described reversible vapochromism behaviour, making these new materials interesting for multi-detection purposes in anti-counterfeiting applications.