Improved Synthesis and X‐Ray Structure of 5‐Aminotetrazolium Nitrate

5‐Aminotetrazolium nitrate was synthesized in high yield and characterized using Raman and multinuclear NMR spectroscopy (¹H, ¹³C, ¹⁵N). The molecular structure of 5‐aminotetrazolium nitrate in the crystalline state was determined by X‐ray crystallography: monoclinic, P 2₁/c, a=1.05493(8) nm, b=0.34556(4) nm, c=1.4606(1) nm, β=90.548(9)°, V=0.53244(8) nm³, Z=4, ϱ=1.847 g cm⁻³, R₁=0.034, wR₂ (all data)=0.090. The thermal stability of 5‐aminotetrazolium nitrate was determined using differential scanning calorimetry; the compound decomposes at 167 °C. The enthalpy of combustion (Δ_combH) of 5‐aminotetrazolium nitrate ([CH₄N₅]⁺[NO₃]⁻) was determined experimentally using oxygen bomb calorimetry: Δ_combH([CH₄N₅]⁺[NO₃]⁻)=−6020±200 kJ kg⁻¹. The standard enthalpy of formation (Δ_fH°) of [CH₄N₅]⁺[NO₃]⁻ was obtained on the basis of quantum chemical computations at the electron‐correlated ab initio MP2 (second order Møller‐Plesset perturbation theory) level of theory using a correlation consistent double‐zeta basis set (cc‐pVTZ): Δ_fH°([CH₄N₅]⁺[NO₃]⁻(s))=+87 kJ mol⁻¹=+586 kJ kg⁻¹. The detonation velocity (D) and the detonation pressure (P) of 5‐aminotetrazolium nitrate were calculated using the empirical equations by Kamlet and Jacobs: D([CH₄N₅]⁺[NO₃]⁻)=8.90 mm μs⁻¹ and P([CH₄N₅]⁺[NO₃]⁻)=35.7 GPa.     

High energetic materials: Reaction of Azides with Dioxygenyl Salts

The reactivity of sodium azide, activated sodium azide and hydrazinium azide towards various dioxygenyl salts was studied. Under no circumstances the formation of dioxygenyl azide, O₂N₃, could be observed. This is in agreement with high level quantumchemical ab initio computations at correlated level (MP2, PMP2, CISD), predicting the decomposition of hypothetical O₂⁺(g)/N₃⁻(g) to be thermodynamically highly favorable (MP2: −326; PMP2: −328; CISD; −369 [kcal/mol]). The combustion of O₂BF₄ with either N₂H₅N₃ (spontaneous reaction on contact in a coaxial solid-propellant system) or NaN₃ (safe to handle, highly exothermic reaction after ignition) is discussed in terms of high-energy-density materials (HEDM).      

Transition metal α-carbonyl diazoalkane coordination chemistry: structures derived from a side-on diazomalonate platinum complex

The labile side-on α-carbonyl diazoalkane platinum complex (dtbpm-κ²P)Pt[N₂C(CO₂Me)₂-κ²N,N′] (2) displays nucleophilic as well as electrophilic reactivity patterns. H₂O is added stoichiometrically, forming the hydrazonido hydroxo platinum(II) complex (dtbpm-κ²P)Pt(OH)[NHNC(CO₂Me)₂] (3). Protonation of 2 with BF₃·OEt₂ and MeOH yields [(dtbpm-κ²P)Pt{NHNC(CO₂Me)₂-κN,κO}]⁺[BF₄]⁻ ([4]⁺[BF₄]⁻). Both new complexes have been fully characterized spectroscopically and by single crystal X-ray diffraction.     

One 2D anionic coordination polymer with {[Co(H2O)6]}2 + cationic guest for fast and selective adsorption of cationic dyes

One new anionic Coordination Polymer, namely [Co(H₂O)₆]^2 +·[Co₃(bptc)₂(H₂O)₁₀]^2 −·3H₂O (1), where H₄bptc = 3,3′,5,5′-biphenyltetracarboxylate, has been synthesized hydrothermally and characterized. In compound 1, bptc^4 − as tridentate ligands connect the Co^2 + cations to form a 2D layer with 1D pseudo channels encapsulation of [Co(H₂O)₆]^2 + guest. In addition, their adsorption activities for organic dyes were investigated in aqueous solution. The results suggested that the anionic complex 1 show rapid and selective adsorption of cationic dyes for Neutral red, Methylene blue.     

pH-dependent assembly of 1D–2D structures based on both {V10O28} and [NiMo6O24H6]4 − units: Synthesis,structure and magnetic properties

Two novel complexes [H₂N(CH₂CH₂)₂O]₄[Na(H₂O)₂{O(CH₂CH₂)₂NH₂}]₂[Na(H₂O)₄]₂[V₁₀O₂₈][NiMo₆O₂₄H₆]·8H₂O (1) and [H₂N(CH₂CH₂)₂O]₆[Na(H₂O)₃]₂[V₁₀O₂₈H₂][NiMo₆O₂₄H₆]·4H₂O (2) containing both isopolyvanadate {V₁₀O₂₈} and [NiMo₆O₂₄H₆]^4 − units have been synthesized and structurally characterized for the first time, showing that the pH value of the reaction plays a key role in structure control of self-assembled processes. Compound 1 exhibits a novel one-dimensional (1-D) chain-like structure consisting of Anderson-type [NiMo₆O₂₄H₆]^4 − and isopolyvanadate [V₁₀O₂₈]^6 − anions linked by Na⁺ ions. In compound 2 with the lower pH value, [NiMo₆O₂₄H₆]^4 − and [V₁₀O₂₈H₂]^4 − anions are bridged by [Na₂O₁₀] units to form the 2D extended layer. The magnetic properties of 1 and 2 are presented.     

A rare polyoxometalate based on mixed niobium-based polyoxoanions [GeNb18O54]14 − and [Nb3W3O19]5 −

Polyoxoniobate [GeNb₁₈O₅₄]^14 − and polyniobotungstate [Nb₃W₃O₁₉]^5 − are firstly found to co-crystallize at the same crystal to form a rare organic–inorganic hybrid polyoxometalate H[Cu(en)₂(H₂O)]₈[Cu(en)₂(H₂O)₂]₂{K₄[Cu(en)₂]₂[Cu(en)₂(GeNb₁₈O₅₄)]₂}[Nb₃W₃O₁₉]·32H₂O (1). Interestingly, in 1, the crescent-shaped polyoxoanions [GeNb₁₈O₅₄]^14 − can form dimeric secondary building units (SBUs) {[GeNb₁₈O₅₄]₂[K₂(H₂O)₅]₂} via the linkage of K⁺ cations. These dimeric SBUs can be further bridged by copper complexes to generate 1D infinite double strand chains with completely different isolated polyoxoanions [Nb₃W₃O₁₉]^5 − filling the gaps between chains.     

Hexachloroplatinate(IV) anion-induced cucurbit[5]uril and cucurbit[8]uril supramolecular assemblies with linear channels

Two Q[n]-based porous compounds, Q[5]·[PtCl₆]^2 −·2H₃O·12H₂O and 2Q[8]·[PtCl₆]^2 −·2H₃O·74H₂O in cooperating the hexachloroplatinate(IV) anion ([PtCl₆]^2 −) as an inorganic structure directing agent are demonstrated. The driving forces for the formation of such novel Q[n]-based porous compounds are considered to be the outer surface interactions of Q[n]s, including dipole interactions between Q[n]s and ion-dipole interactions between [PtCl₆]^2 − anions and Q[n]s. Moreover, the Q[5]-based porous compound displays absorption distinctness for tetrachloromethane, whereas the Q[8]-based porous compound displays absorption distinctness for methanol.     

Functionalization of halloysite nanotubes with polyethyleneimine and various ionic liquid forms with antimicrobial activity

Halloysite nanotube (HNT), a natural clay, was modified with branched polyethyleneimine (PEI) to form PEI-HNT using epichlorohydrin (ECH) as coupling agent, then protonated with HCl to obtain H-PEI-HNTs providing [NH₃]⁺[Cl]⁻ functionality for potential antimicrobial properties. Upon PEI modification, zeta potential value of HNTs was increased to +37.3 mV from −34.5 mV and to +41.1 mV for H-PEI-HNTs. Only 1.87 wt % H-element in HNT was increased to 3.03 wt % upon PEI modification along with newly generated elements of N and C at 2.99 and 9.93 wt %, respectively. Moreover, ionic liquid (IL) forms of HNTs with [NH₃]⁺[N(CN)₂]⁻, [NH₃]⁺[PF₆]⁻ and [NH₃]⁺[BF₄]⁻ functionality were generated via anion exchange of H-PEI-HNTs with sodium dicyanamide (SDC), ammonium hexafluorophosphate (AHFP), and sodium tetrafluoroborate (STFB). The antimicrobial properties of the modified, protonated, and IL forms of HNTs were determined via macro dilution, diffusion and agar screening tests against Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 10145, Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538 strains, and Candida albicans ATCC 10231 strains. It was found that H-PEI-HNTs possesses potent antimicrobial effect compared with the other forms of HNTs with 2–4 mg mL⁻¹ MIC and 8–16 mg mL⁻¹ MBC values via the macro dilution method. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48352.     

A heterobimetallic copper(I)–silver(I) complex spanned by 4,4′-bipyridine

Cationic heterobimetallic {[P(C₆H₄CH₂NMe₂-2)₃]Ag-bipy-Cu[P(C₆H₄CH₂NMe₂-2)₃]}²⁺(OTf⁻,PF₆⁻) (5) (bipy = 4,4^′-bipyridine, OTf=OSO₂CF₃) is accessible by the subsequent reaction of [P(C₆H₄CH₂NMe₂-2)₃]AgOTf (1) with bipy (2) to afford {[P(C₆H₄CH₂NMe₂-2)₃]Ag(bipy)}⁺(OTf⁻) (3), which on treatment with equimolar amounts of {[P(C₆H₄CH₂NMe₂-2)₃]Cu}⁺(PF₆⁻) (4) produces 5. In 5 the respective group-11 metal(I) centres are bridged by the π-conjugated organic ligand bipy. The electrochemical behaviour of 5 is reported.     

Linear Chain Ferromagnetic Charge Transfer Compounds

Charge transfer complexes possessing a … DADA … structure with both the donor, D, and acceptor, A, being S = 1/2 radicals may exhibit cooperative magnetic phenomena. The complex [Fe(C₅Me₅)₂]⁺·[TCNQ]⁻· exhibits metamagnetic behavior. The similarly structured [TCNE]⁻· and [C₄(CN)₆]⁻· complexes are ferromagnets, whereas the [DDQ]⁻· salt is a paramagnet. The high temperature magnetic susceptibility obeys the Curie-Weiss expression with θ = + 30, + 30, and + 3 for the [TCNE]⁻·, [C₄(CN)₆]⁻·, and [TCNQ]⁻· salts, respectively. The ferromagnetic [TCNE]⁻· salt exhibits zero field Zeeman split ⁵⁷Fe Mossbauer spectra with an internal field of 425.6 kOe at 4.23 K. After reviewing the current papers discussing ferromagnetism in molecular (organic) compounds, a qualitative model consistent with the necessary bulk spin alignment required for a ferromagnet is presented.     

X-Ray crystal structure of the Dye 2,4,6-Tricyano-4'-N,N-diethylaminoazobenzene

The crystal structure and molecular conformation of 2,4,6-tricyano-4'-N,N-diethylaminoazobenzene (C₁₉H₁₆N₆, mol. wt. 328.4a.m.u.) has been determined from X-ray diffraction data: monoclinic P2₁/c, a = 9.302(7)Å, b = 8.733(5)Å, c = 20.98(1) Å, β = 94.93(6)°, V = 1699(2)ų, Z = 4, D_c = 1.284gem^?3, F(000) = 688, λ(MoKα) = 0-71069Å, μ(MoKα) = 0.76cm^?1. The structure was solved by MULTAN andrefined by full-matrix least-squares toR = 0.050 for 1358 independent observed reflections. The azobenzene skeleton is planar to within 0.12Å. Most significant bonding data are: NN, 1.286(4) Å; mean C-N (azo) 1.383(4) Å; mean C-C (cyano) 1.439(5) Å; mean CN 1.146(5)Å; NN-C, 112.8(2)° and 115.9(2)°; N-C-C (cis relative to NN) 127.6(2)° and 124.3(2)° ; N- C- C(trans) 115.2(2)° and 117.7(2)°.     

Two new carboxylate–oxygen bridged trinuclear M(II) (MMn and Co) compounds with zwitterionic dicarboxylate ligands: crystal structures and magnetism

Two new Mn(II) and Co(II) coordination polymers with azide and zwitterionic dicarboxylate ligands L¹ and L² (L¹ = [4-((1-carboxylatobenzyl)pyridimium-3-yl) benzoic acid] chloride, L² = [1,1′-bis(4-carboxylatobenzyl)-4,4′-bipyridinium] dichloride) were synthesized and structurally and magnetically characterized. They are formulated as [Mn₃(L¹)₄(N₃)(CH₃CH₂OH)(H₂O)]ClO₄·4H₂O (1) and [Co₃(L²)₄(N₃)₂(H₂O)₂]·4NO₃ (2). Compound 1 contains two different linear trinuclear [Mn₃(COO)₈(CH₃CH₂OH)₂]^2 − and [Mn₃(COO)₆(H₂O)₂(N₃)₂]^2 − units built from the mixed bridges of (μ-COO)₂(μ₂-O_carboxylate). The trinuclear units are alternately linked into 1D chains by L¹. Compound 2 contains linear trinuclear [Co₃(N₃)₂(COO)₄(H₂O)₂] units built from the mixed bridges (μ-COO)₂(μ-H₂O). Magnetic studies demonstrated that the mixed triple bridges are antiferromagnetic in compounds 1 and 2.     

Kinetics of ligand exchange reaction of Cu(II)-ammine complex with poly(vinyl alcohol) in aqueous solution

The kinetics of the ligand exchange reaction of the Cu(II)-ammine complex with poly(vinyl alcohol) (PVA) has been studied by a stopped-flow method at pH 9–10, at μ=0.1 (NH₄Cl) and at 25°C. The reaction is initiated by the formation of unstable [Cu(NH₃)₃]²⁺ by the attack of H⁺ on Cu(II)-ammine complex, and proceeds through the mixed complex {[Cu(NH₃)₃(O?PVA)]²⁺}. This step may be rate-determining, followed by a rapid reaction. Finally, the Cu(II) ion is taken up by PVA. The rate is given by d[Cu(II)?PVA]/dt=k[H⁺]{[Cu(NH₃)₄]²⁺}[PVA]/[NH₄Cl], where k=k₁ + k′₂[H⁺], k₁=4.25× 10s^?1 and k′₂=5.20× 10¹¹l mol^?1s^?1.     

A study on proton conduction in a layered metal–organic framework,Rb2(adp)[Zn2(ox)3]·3H2O (adp = adipic acid,ox2 − = oxalate)

We newly synthesized a metal–organic framework (MOF) Rb₂(adp)[Zn₂(ox)₃]·3H₂O (adp = adipic acid; ox^2 − = oxalate), where the rubidium ions, carboxylic acid groups, and water molecules are located in an interlayer space of a two-dimensional (2-D) oxalate-bridged network. The structure of this compound was determined using single-crystal X-ray diffraction analysis. Hydrated phases of this compound were examined using thermogravimetry and water vapor adsorption measurements. Proton conductivity in this MOF was investigated by alternating current impedance measurements. Systematic comparison with previously reported isomorphous 2-D compounds A₂(adp)[Zn₂(ox)₃]·3H₂O (A = NH₄ and K) showed that the difference in the ionic radii of the cations leads to a difference in activation energy of proton conductivity and that absence of NH₄⁺ ions causes a significant decrease in proton conductivity, even though the ionic radius of Rb⁺ (1.52 Å) is closer to that of NH₄⁺ (1.61 Å) than that of K⁺ (1.38 Å).     

A novel Dawson-like cerium(IV)-hybridizing selenotungstate Na13H7[Ce(SeW17O59)2]·31H2O

A novel cerium(IV)-hybridizing selenotungstate with Dawson-like structure Na₁₃H₇[Ce(SeW₁₇O₅₉)₂]·31H₂O (1) has been synthesized by reaction of Na₂WO₄·2H₂O, Na₂SeO₃ and (NH₄)₂Ce(NO₃)₆ in the aqueous solution and characterized by elemental analysis, IR spectrum, UV spectrum, thermogravimetric analysis (TGA) and single-crystal X-ray diffraction. To the best of our knowledge, 1 stands for 1:2-type Dawson-like selenotungstate constructed from two identical [SeW₁₇O₅₉]^12 − moieties combined via one Ce^4 + ion. The Ce^4 + cation displays a distorted square prismatic geometry defined by eight oxygen atoms from two [SeW₁₇O₅₉]^12 − moieties. In the [Ce(SeW₁₇O₅₉)₂]^20 − polyoxoanion, the {SeO₃} trigonal pyramid encapsulated into the [SeW₁₇O₅₉]^12 − fragment is situated on the side close to the Ce^4 + ion. The TGA curve of 1 reveals two steps of weight loss between 25 °C and 700 °C. Furthermore, the electrochemical and the electrocatalytic properties of 1 have been measured by cyclic voltammetry (CV) in 0.5 M Na₂SO₄ + H₂SO₄ aqueous solution.     

A new binuclear Cr(III) citrate anion: Synthesis,characterization and crystal structure of [Cr(CO(NH2)2)6]2[Cr2(CO(NH2)2)2(C6H4O7)2]3

The new anion [Cr₂(CO(NH₂)₂)₂(C₆H₄O₇)₂]^2 − has been isolated in the complex [Cr(CO(NH₂)₂)₆]₂[Cr₂(CO(NH₂)₂)₂(C₆H₄O₇)₂]₃. The crystals of this complex were obtained by a one-pot synthetic method using 1:1 molar ratio of hexaureachromium(III) chloride and trisodium citrate in aqueous medium. It was characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction analysis. The compound crystallizes in space group R‾3 of the trigonal system with three formula units in a cell of dimensions a = b = 24.7461(4) Å, c = 13.7204(3) Å and γ = 120°. The crystal structure comprises the columns consisting of [Cr(CO(NH₂)₂)₆]^3 + cations surrounded by a cylinder of complex anions, [Cr₂(CO(NH₂)₂)₂(C₆H₄O₇)₂]^2 − which are packed in a honeycomb-like manner. This supramolecular architecture is formed and stabilized by inter- and intramolecular NH⋯O hydrogen bonds.     

UNIFAC model for ionic liquid‐CO (H2) systems: An experimental and modeling study on gas solubility

The universal quasichemical functional‐group activity coefficients (UNIFAC) model for ionic liquids (ILs) has become notably popular because of its simplicity and availability via modern process simulation softwares. In this work, new group binary interaction parameters (α_mn and α_nm) between CO (H₂) and IL groups were obtained by correlating the solubility data in pure ILs at high temperatures (above 273.2 K) collected from the literature. the solubility of CO in [BMIM]⁺[BF₄]^?, [OMIM]⁺[BF₄]^?, [OMIM]⁺[Tf₂N]^?, and their mixtures, as well as that of H₂ in [EMIM]⁺[BF₄]^?, [BMIM]⁺[BF₄]^?, [OMIM]⁺[Tf₂N]^?, and their mixtures, at temperatures from 243.2 to 333.2 K and pressures up to 6.0 MPa were measured. The UNIFAC model was observed to well predict the solubility in pure and mixed ILs at both high (above 273.2 K) and low (below 273.2 K) temperatures. Moreover, the selectivity of CO (or H₂) to CO₂ in ILs increases with decreasing temperature, indicating that low temperatures favor for gas separation. © 2014 American Institute of Chemical Engineers AIChE J 60: 4222–4231, 2014     

Co-polymerization of propylene oxide and CO2 using early transition metal (groups IV and V) metallocalix[n]arenes (n = 4, 6, 8)

A number of metallocalix[n]arenes, where n = 4, 6, or 8, of titanium and vanadium have been screened for their ability to act as catalysts for the co-polymerization of propylene oxide and CO₂ to form cyclic/polycarbonates. The vanadium-containing catalysts, namely [VO(L¹Me)] (1), [(VO₂)L²H₆] (2), [Na(NCMe)₆]₂[(Na[VO]₄L²)(Na(NCMe))₃]₂ (3), [VO(μ-OH)L^3/H₂]₂∙6CH₂Cl₂ (4), {[VO]₂(μ-O)L⁴[Na(NCMe)₂]₂} (5), {[V(Np-tolyl)]₂L⁴} (6) and [V(Np-RC₆H₄)Cl₃] (R = Cl (7), OMe (8), CF₃ (9)), where L¹H₃ = methylether-p-tert-butylcalix[4]areneH₃, L²H₈ = p-tert-butylcalix[8]areneH₈, L³H₄ = p-tert-butylthiacalix[4]areneH₄, L⁴H₆ = p-tert-butyltetrahomodioxacalix[6]areneH₆, performed poorly, affording, in the majority of cases, TONs less than 1 at 90°C over 6 h and low molecular weight oligomeric products (M_n ≤ 1665). In the case of the titanocalix[8]arenes, {(TiX)₂[TiX(NCMe)]₂(μ₃-O)₂(L²)} (X = Cl (10), Br (11), I (12)), which all adopt a similar, ladder-type structure, the activity under the same conditions is somewhat higher (TONs >6) and follows the trend Cl > Br > I; by comparison the non-calixarene species [TiCl₄(THF)₂] was virtually inactive. In the case of 10, it was observed that the use of PPNCl (bis[triphenylphosphine]iminium chloride) as co-catalyst significantly improved both the polymer yield and molecular weight (M_n 3515). The molecular structures of the complexes [HNEt₃]₂[VO(μ-O)L³H₂]₂∙3CH₂Cl₂ (4∙3CH₂Cl₂), [VO(μ-OH)L^3/H₂]₂∙6CH₂Cl₂ (4^/) (where L^3/H₂ is a partially oxidized form of L³H₄) and {(TiCl)₂[TiCl(NCMe)]₂(μ₃-O)₂(L²)}·6.5MeCN (10·6.5MeCN) are reported.     

Syntheses,structural characterization and electrochemical properties of two rare-earth–isonicotinic-acid containing silicomolybdates

Two rare-earth–isonicotinic-acid containing silicomolybdates [NH₄]₆[RE(INA)₂(HINA)(H₂O)₃]₂[α-SiMo₁₂O₄₀]₂·6H₂O [RE = Nd^III (1), Er^III (2); HINA = isonicotinic acid] have been synthesized in the conventional aqueous solution and characterized by elemental analyses, IR spectra, UV spectra and single-crystal X-ray diffraction. Both 1 and 2 crystallize in the triclinic P–1 space group and consist of two typical Keggin [α-SiMo₁₂O₄₀]^4 − polyanions, one isolated rare-earth-isonicotinic-acid [RE(INA)₂(HINA)(H₂O)₃]₂^2 + dimeric complex cation, six NH₄⁺ ions and six lattice water molecules. Interestingly, two rare-earth ions are linked by four INA⁻ ligands in the [Ln(INA)₂(HINA)(H₂O)₃]₂^2 + complex cation, which is very rare in polyoxometalate chemistry. The UV spectral measurements of 1 indicate that 1 is stable in aqueous solution in the pH range of 4.49–9.39. Furthermore, the electrochemical and electrocatalytic properties of 1 have been measured by cyclic voltammetry in 0.5 mol·L^− 1 Na₂SO₄ + H₂SO₄ aqueous solution at the scan rate of 100 mV·s^− 1.