Elimination of 4‐chlorophenol in aqueous solution by the Novel Pd/MIL‐101(Cr)‐Hydrogen‐Accelerated catalytic fenton system

Excessive consumption of Fe (II) and massive generation of sludge containing Fe (III) from classic Fenton process remains a major obstacle for its poor recycling of Fe (III) to Fe (II). Therefore, the MHACF‐MIL‐101(Cr) system, by introducing H₂, Pd⁰ and MIL‐101(Cr) into Fenton reaction system, was developed at normal temperature and pressure. In this system, the reduction of Fe^III back to Fe^II by solid catalyst Pd/MIL‐101(Cr) for the storage and activation of H₂, was accelerated significantly by above 10‐fold and 5‐fold controlled with the H₂‐MIL‐101(Cr) system and H₂‐Pd⁰ system, respectively. However, the concentration of Fe (II) generated by the reduction of Fe (III) could not be detected with the only input of H₂ and without the addition of MOFs material. In addition, the apparent consumption of Fe (II) in MHACF‐MIL‐101(Cr) system was half of that in classical Fenton system, while more Fe (II) might be reused infinitely in fact. Accordingly, only trace amount of Fe (II) vs H₂O₂ concentration was needed and hydroxyl radicals through the detection of para‐hydroxybenzoic acid (p‐HBA) as the oxidative product of benzoic acid (BA) by·OH could be continuously generated for the effective degradation of 4‐chlorophenol(4‐CP). The effects of initial pH, concentration of 4‐CP, dosage of Fe²⁺, H₂O₂ and Pd/MIL‐101(Cr) catalyst, Pd content and H₂ flow were investigated, combined with systematic controlled experiments. Moreover, the robustness and morphology change of Pd/MIL‐101(Cr) were thoroughly analyzed. This study enables better understanding of the H₂‐mediated Fenton reaction enhanced by Pd/MIL‐101(Cr) and thus, will shed new light on how to accelerate Fe (III)/Fe (II) redox cycle and develop more efficient Fenton system.     

A Dinuclear Ruthenium(II) Complex as a One‐ and Two‐Photon Luminescent Probe for Biological Cu2+ Detection

A new dinuclear Ru^II polypyridyl complex, [(bpy)₂Ru(H₂bpip)Ru(bpy)₂]⁴⁺ ( RuH₂bpip , bpy=2,2‐bipyridine, H₂bpip=2,6‐pyridyl(imidazo[4,5‐f][1,10]phenanthroline), was developed to act as a one‐ and two‐photon luminescent probe for biological Cu²⁺ detection. This Ru^II complex shows a significant two‐photon absorption cross section (400 GM) and displays a remarkable one‐ and two‐photon luminescence switch in the presence of Cu²⁺ ions. Importantly, RuH₂bpip can selectively recognise Cu²⁺ in aqueous media in the presence of other abundant cellular cations (such as Na⁺, K⁺, Mg²⁺, and Ca²⁺), trace metal ions in organisms (such as Zn²⁺, Ag⁺, Fe³⁺, Fe²⁺, Ni²⁺, Mn²⁺, and Co²⁺), prevalent toxic metal ions in the environment (such as Cd²⁺, Hg²⁺, and Cr³⁺), and amino acids, with high sensitivity (detection limit≤3.33×10^?8 M ) and a rapid response time (≤15 s). The biological applications of RuH₂bpip were also evaluated and it was found to exhibit low cytotoxicity, good water solubility, and membrane permeability; RuH₂bpip was, therefore, employed as a sensing probe for the detection of Cu²⁺ in living cells and zebrafish.     

Self‐Assembly of [B‐SbW9O33]9− Subunit with Transition Metal Ions (Mn2+, Cu2+, Co2+) in Aqueous Solution: Syntheses,Structures and Magnetic Properties of Sandwich Type Polyoxometalates with Subvalent SbIII Heteroatom

Rational self‐assembly of Sb₂O₃ and Na₂WO₄, or (NH₄)₁₈[NaSb₉W₂₁O₈₆] with transition‐metal ions (Mn²⁺, Cu²⁺, Co²⁺), in aqueous solution under controlled conditions yield a series of sandwich type complexes, namely, Na₂H₂[Mn_2.5W_1.5(H₂O)₈(B‐β‐SbW₉O₃₃)₂]?32 H₂O (1) , Na₄H₇[Na₃(H₂O)₆Mn₃(μ‐OAc)₂(B‐α‐SbW₉O₃₃)₂]?20 H₂O (OAc=acetate anion) (2) , NaH₈[Na₂Cu₄Cl(B‐α‐SbW₉O₃₃)₂]?21 H₂O (3) , Na₈K[Na₂K(H₂O)₂{Co(H₂O)}₃(B‐α‐SbW₉O₃₃)₂]? 10 H₂O (4) , and Na₅H[{Co(H₂O)₂}₃W(H₂O)₂(B‐β‐SbW₉O₃₃)₂]?11.5 H₂O (5) . These structures are determined by using the X‐ray diffraction technique and further characterized by obtaining IR spectra and performing elemental analysis. Structure analysis reveals that polyoxoanions in 1 and 5 comprise of two [B‐β‐SbW₉O₃₃]^9? building units, whereas 2 , 3 , and 4 consist of two isomerous [B‐α‐SbW₉O₃₃]^9? building blocks, which are all linked by different transition‐metal ions (Mn²⁺, Cu²⁺, or Co²⁺) with different quantitative nuclearity. It should be noted that compound 2 represents the first one‐dimensional sinusoidal chain based on sandwich like tungstoantimonate building blocks through the carboxylate‐bridging ligands. Additionally, 3 is constructed from sandwiched anions [Na₂Cu₄Cl(B‐α‐SbW₉O₃₃)₂]^9? linked to each other to form an infinitely extended 2D network, whereas 5 shows an interesting 3D framework built up from offset sandwich type polyoxoanion [{Co(H₂O)₂}₃W(H₂O)₂(B‐β‐SbW₉O₃₃)₂]^6? linked by Co²⁺ and Na⁺ ions. EPR studies performed at 110 K and room temperature reveal that the metal cations (Mn²⁺, Cu²⁺, Co²⁺) reside in a square‐pyramidal geometry in 2 , 3 , and 4 . The magnetic behavior of 1 – 4 suggests the presence of weak antiferromagnetic coupling interactions between magnetic metal centers with the exchange integral J=?0.552 cm^?1 in 2 .     

Preparation and catalysis of chloromethylated polystyrene‐supported macrocyclic Schiff base metal complexes for the oxidation of cumene

Chloromethylated polystyrene‐supported macrocyclic Schiff base metal complexes (PS‐L‐M, M = Cu²⁺, Co²⁺, Ni²⁺, and Mn²⁺) were synthesized and characterized by the methods of IR, ICP, and small area X‐ray photoelectron spectroscopy (XPS). The oxidation of cumene by molecular oxygen in the absence of solvent with the synthesized complexes employed as catalyst was carried out. In comparison with their catalytic activities, PS‐L‐Cu is a more effective catalyst for the oxidation of cumene. The main products are 2‐phenyl‐2‐propanol (PP) and cumene hydroperoxide, which were measured by GC/MS. The influences of reaction temperature, the amount of catalyst, as well as the reaction time on the oxidation of cumene were investigated. Copyright © 2008 John Wiley & Sons, Ltd.     

Comparison between various Keggin and Wells–Dawson sandwich‐type polyoxometalates in catalytic oxidation of cyclooctene and cyclohexene with hydrogen peroxide

The catalytic performance of tetra‐n‐butylammonium salts of Keggin and Wells–Dawson sandwich‐type polyoxotungstates, [M₄(PW₉O₃₄)₂]^m? and [M₄(P₂W₁₅O₅₆)₂]^n? (M = Mn²⁺, Fe³⁺, Co²⁺, Ni²⁺, Zn²⁺), in the oxidation of cyclooctene and cyclohexene with 30% hydrogen peroxide under various conditions was investigated. In comparison, Wells–Dawson sandwich‐type polyoxometalates were found to be less active than Keggin ones. In both of them, those containing Zn and Fe gave higher conversions for different oxidation conditions. These catalysts showed very good reusability in the oxidation reaction. Copyright © 2014 John Wiley & Sons, Ltd.     

Cyano‐Bridged ‘Oximato’ Complexes: Synthesis,Structure, and Catalase‐Like Activities

The reaction of the ‘oximato’‐ligand precursor A (Fig. 1) and metal salts with KCN gave two mononuclear complexes [ML(CN)(H₂O)_n](ClO₄) ( 1 and 2 ; L={N‐(hydroxy‐κO)‐α‐oxo‐N′‐[(pyridin‐2‐yl‐κN)methyl[1,1′‐biphenyl]‐4‐ethanimidamidato‐κN′}; M=Co^II ( 1 ), Cu^II ( 2 ); n=2 for Co^II, n=0 for Cu^II; Figs. 2 and 3). The new cyano‐bridged pentanuclear ‘oximato’ complexes [{ML(H₂O)_n(NC)}₄M¹(H₂O)_x](ClO₄)₂ ( 3 – 6 ) and trinuclear complexes [{ML(H₂O)_n(NC)}₂M¹L](ClO₄) ( 7 – 10 ) ([M¹=Mn^II, Cu^II; x=2 for Mn^II, x=0 for Cu^II] were synthesized from mononuclear complexes and characterized by elemental analyses, magnetic susceptibility, molar conductance, and IR and thermal analysis. The four [ML(CN)(H₂O)_n]⁺ moieties are connected by a metal(II) ion in the pentanuclear complexe 3 – 6 , each one involving four cyano bridging ligands (Fig. 4). The central metal ion displays a square‐planar or octahedral geometry, with the cyano bridging ligands forming the equatorial plane. The axial positions are occupied by two aqua ligands in the case of the central Mn‐atom. The two [ML(CN)(H₂O)_n]⁺ moieties and an ‘oximato’ ligand are connected by a metal(II) ion in the trinuclear complexes 7 – 10 , each one involving two cyano bridging ligands (Fig. 5). The central metal ions display a distorted square‐pyramidal geometry, with two cyano bridging ligands and the donor atoms of the tridentate ‘oximato’ ligand. Moreover catalytic activities of the complexes for the disproportionation of hydrogen peroxide (H₂O₂) were also investigated in the presence of 1H‐imidazole. The synthesized homopolynuclear Cu^II complexes 6 and 10 displayed eficiency in disproportion reactions of H₂O₂ producing H₂O and dioxygen thus showing catalase‐like activity.     

Simultaneous Fenton‐like Ion Delivery and Glutathione Depletion by MnO2‐Based Nanoagent to Enhance Chemodynamic Therapy

Chemodynamic therapy (CDT) utilizes iron‐initiated Fenton chemistry to destroy tumor cells by converting endogenous H₂O₂ into the highly toxic hydroxyl radical (^.OH). There is a paucity of Fenton‐like metal‐based CDT agents. Intracellular glutathione (GSH) with ^.OH scavenging ability greatly reduces CDT efficacy. A self‐reinforcing CDT nanoagent based on MnO₂ is reported that has both Fenton‐like Mn²⁺ delivery and GSH depletion properties. In the presence of HCO₃^?, which is abundant in the physiological medium, Mn²⁺ exerts Fenton‐like activity to generate ^.OH from H₂O₂. Upon uptake of MnO₂‐coated mesoporous silica nanoparticles (MS@MnO₂ NPs) by cancer cells, the MnO₂ shell undergoes a redox reaction with GSH to form glutathione disulfide and Mn²⁺, resulting in GSH depletion‐enhanced CDT. This, together with the GSH‐activated MRI contrast effect and dissociation of MnO₂, allows MS@MnO₂ NPs to achieve MRI‐monitored chemo–chemodynamic combination therapy.     

Highly Efficient AuPd/Carbon Nanotube Nanocatalysts for the Electro‐Fenton Process

Development of novel nanocatalysts for the highly efficient in situ synthesis of H₂O₂ from H₂ and O₂ in the electro‐Fenton (EF) process has potential for the remediation of water pollution. In this work, AuPd/carbon nanotube (CNT) nanocatalysts were successfully synthesized by the facile aggregation of AuPd bimetals on CNTs. Characterization by X‐ray diffraction, transmission electron microscopy, and X‐ray photoelectron spectroscopy indicated that pure AuPd bimetallic heterogeneous nanospheres (≈20 nm) were well dispersed outside the CNTs, which resulted in better catalytic performance than Pd/CNTs alone: 0.36 M H₂O₂ was synthesized; 0.05 M Fe²⁺ optimally initiated the EF process due to the superior in situ Fe²⁺ regeneration; and the organic pollutant removal reached 100 % at 37 min, with a pseudo‐first‐order kinetic constant k₁=0.051 min^?1. Moreover, structural insights before/after catalysis revealed that Au strengthened the construction of the nanocrystals, avoided negative deactivation caused by AuPd agglomeration, and immobilized the active Pd(111). The catalytic stability of AuPd/CNTs over ten cycles implied long durability and promising applications of this material.     

Metallkomplexe mit biologisch wichtigen Liganden. CLXVI Metallkomplexe mit Ferrocenylmethyl‐L‐cysteinat und 1,1′‐Ferrocenylbis‐(methyl‐L‐cysteinat) als Liganden

Metal Complexes of Biologically Important Ligands. CLXVI Metal Complexes with Ferrocenylmethylcysteinate and 1,1′‐Ferrocenylbis‐(methylcysteinate) as Ligands A series of complexes of transition metal ions ( Cr³⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺ ) and of lanthanide ions ( La³⁺, Nd³⁺, Gd³⁺, Dy³⁺, Lu³⁺ ) with the anions of ferrocenylmethyl‐L‐cysteine [(C₅H₅)Fe(C₅H₄CH(R)SCH₂CH(NH₃⁺)CO₂^?] (L¹) and with the dianions of 1,1′‐ferrocenylbis(methyl‐L‐cysteine) [Fe(C₅H₄CH(R)SCH₂CH(NH₃⁺) CO₂^?)₂] (R = H, Me, Ph) (L²) as N,O,S‐donors were prepared. With the monocysteine ferrocene derivative L¹ as ligands complexes [M^IIL¹₂] or [Cr^IIIL¹₂]Cl type complexes are formed whereas the bis(cysteine) ligand L² yields insoluble complexes of type [ML²]_n, presumably as coordination polymers. The magnetic moments of [Mn^IIL²]_n, [Pr^IIIL²]_n(OH)_n and [Dy^IIIL²]_n(OH)_n exhibit “normal” paramagnetism.     

Sur de nouveaux ferrites oxyfluorés d'yttrium ou de gadolinium à structure grenat

The oxyfluoride garnets of formula Y₃Fe_5?xM_xO_12?xF_x and Gd₃Fe_5?xM_xO_12?xF_x (M = 3d transition element) result from partial substitution of O^2? by F^? in Y₃Fe₅O₁₂ and Gd₃Fe₅O₁₂ oxides. The cationic charge compensation is obtained by replacing the Fe³⁺ ions by divalent ions as Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺ or Zn²⁺ ions. The site occupied by some of these ions (Mn²⁺, Ni²⁺, Zn²⁺) is determined by magnetic or Mössbauer measurements.     

Reactivity of 4‐thiothymidine with Fenton reagent investigated by UV‐visible spectroscopy and electrospray ionization mass spectrometry

The reactivity of the sulfur‐containing nucleoside 4‐thio‐(2′‐deoxy)‐thymidine usually abbreviated as 4‐thio‐thymidine, (S⁴‐TdR) under Fenton conditions, ie, in the presence of H₂O₂ and catalytic amounts of Fe(II), was investigated by UV‐vis spectroscopy and electrospray ionization single and tandem mass spectrometry (ESI‐MS and MS/MS). S⁴‐TdR hydroxylated on the S atom was found to be a key reaction intermediate, ultimately leading to (2′‐deoxy)‐thymidine usually abbreviated as thymidine, (TdR) as the main reaction product. This finding was in accordance with the outcome of the reaction between S⁴‐TdR and H₂O₂, previously investigated in our laboratory. On the other hand, the additional presence of ?OH radicals, induced by the Fe(II)/H₂O₂ combination, led to the increased generation of another interesting S⁴‐TdR product, already observed after its reaction with H₂O₂ alone, ie, the covalent dimer including a S? S bridge between two S⁴‐TdR molecules. More importantly, multihydroxylated derivatives of S⁴‐TdR and TdR were detected as peculiar products obtained under Fenton conditions. Among them, a product bearing an OH group both on the methyl group linked to the thymine ring and on the C5 atom of the ring was found to prevail. The results obtained during this study, integrated by those found previously in our laboratory, indicate 4‐thiothymidine as a promising molecular probe for the recognition, through a careful characterization of its reaction products, of the prevailing species among reactive oxygen species (ROS) corresponding to singlet‐state oxygen, hydrogen peroxide, and hydroxylic radical.     

Synthesis of ultra‐high molecular weight polymers by controlled production of initiating radicals

This study demonstrates that the gradual and slow production of initiating radicals (i.e., hydroxyl radicals here) is the key point for the synthesis of ultra‐high molecular weight (UHMW) polymers via controlled radical polymerization. Hydrogen peroxide (H₂O₂) and ferrous iron (Fe²⁺) react via Fenton redox chemistry to initiate RAFT polymerization. This work presents two enzymatic‐mediated (i.e., Bio‐Fenton‐RAFT and Semi Bio‐Fenton‐RAFT) and one syringe pump‐driven Fenton‐RAFT polymerization processes in which the initiating radicals are carefully and gradually dosed into the reaction solution. The “livingness” of the synthesized UHMW polymers is demonstrated by chain extension and aminolysis experiments. Zimm plots obtained from static light scattering (SLS) technique are used to characterize the UHMW polymers. This Fenton‐RAFT polymerization provides access to polymers of unprecedented UHMW (M_w ~ 20 × 10⁶ g mol^?1) with potential in diverse applications. The UHMW polymers made via the controlled Fenton‐RAFT polymerization by using a syringe pump shows that it is possible to produce such materials through an easy‐to‐set up and scalable process. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1922–1930     

Postsynthetic Metal and Ligand Exchange in MFU‐4l: A Screening Approach toward Functional Metal–Organic Frameworks Comprising Single‐Site Active Centers

The isomorphous partial substitution of Zn²⁺ ions in the secondary building unit (SBU) of MFU‐4l leads to frameworks with the general formula [M_xZn_(5–x)Cl₄(BTDD)₃], in which x≈2, M=Mn^II, Fe^II, Co^II, Ni^II, or Cu^II, and BTDD=bis(1,2,3‐triazolato‐[4,5‐b],[4′,5′‐i])dibenzo‐[1,4]‐dioxin. Subsequent exchange of chloride ligands by nitrite, nitrate, triflate, azide, isocyanate, formate, acetate, or fluoride leads to a variety of MFU‐4l derivatives, which have been characterized by using XRPD, EDX, IR, UV/Vis‐NIR, TGA, and gas sorption measurements. Several MFU‐4l derivatives show high catalytic activity in a liquid‐phase oxidation of ethylbenzene to acetophenone with air under mild conditions, among which Co‐ and Cu derivatives with chloride side‐ligands are the most active catalysts. Upon thermal treatment, several side‐ligands can be transformed selectively into reactive intermediates without destroying the framework. Thus, at 300 °C, Co^II‐azide units in the SBU of Co‐MFU‐4l are converted into Co^II‐isocyanate under continuous CO gas flow, involving the formation of a nitrene intermediate. The reaction of Cu^II‐fluoride units with H₂ at 240 °C leads to Cu^I and proceeds through the heterolytic cleavage of the H₂ molecule.     

Valence Distributions of Iron and Manganese in Pure,Manganese‐doped and Calcium‐doped Yttrium Orthoferrite

The valence distributions of Fe and Mn in yttrium orthoferrite (YFeO,), YFe_0.6Mn0.4O3 and Y_0.9Ca_0.1Fe_0.6Mn_0.4O_3.8 were studied by the measurement of thermal power. Pure YFeO₃ shows the n‐type electrical conductivity associated with small polaron hopping between Fe²⁺ and Fe³⁺. Both YFe_0.4Mn_0.4‐O₃ and Y_0–9Ca_0–1.Fe_0–6Mn_0–4O_3–8 show n‐type and p‐type conductivities at high and low temperatures respectively associated with small polaron hopping between Mn³⁺ and Mn⁴⁺, iron has only oxidation state of Fe³⁺ and does not have contribution to the electrical conductivity.     

Synthesis and characterization of La0.8Sr1.2Co0.5M0.5O4−δ (M=Fe, Mn)

The M⁴⁺-containing K₂NiF₄-type phases La_0.8Sr_1.2Co_0.5Fe_0.5O₄ and La_0.8Sr_1.2Co_0.5Mn_0.5O₄ have been synthesized by a sol–gel procedure and characterized by X-ray powder diffraction, thermal analysis, neutron powder diffraction and Mössbauer spectroscopy. Oxide ion vacancies are created in these materials via reduction of M⁴⁺ to M³⁺ and of Co³⁺ to Co²⁺. The vacancies are confined to the equatorial planes of the K₂NiF₄-type structure. A partial reduction of Mn³⁺ to Mn²⁺ also occurs to achieve the oxygen stoichiometry in La_0.8Sr_1.2Co_0.5Mn_0.5O_3.6. La_0.8Sr_1.2Co_0.5Fe_0.5O_3.65 contains Co²⁺ and Fe³⁺ ions which interact antiferromagnetically and result in noncollinear magnetic order consistent with the tetragonal symmetry. Competing ferromagnetic and antiferromagnetic interactions in La_0.8Sr_1.2Co_0.5Fe_0.5O₄, La_0.8Sr_1.2Co_0.5Mn_0.5O₄ and La_0.8Sr_1.2Co_0.5Mn_0.5O_3.6 induce spin glass properties in these phases.     

Macrocyclic Polysiloxane Immobilized Ligand System and Its Structural Characterization

A new porous solid macrocyclic 1,4,7,10,14,17,20‐heptaazadocosane‐3,21‐dione polysiloxane ligand system of the general formula P‐(CH₂)₃‐C₁₅H₃₂O₂N₅, (where P represents [Si‐O]n siloxane network) has been prepared by the reaction of immobilized iminobis(N‐diethylenediamineacetamide)polysiloxane with 1,3 dibromopropane. The new macrocyclic polysiloxane ligand system exhibits high potential for the uptake of metal ions (Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺). Complexation with copper ions exhibits a high selectivity in which two copper ions were involved per one macrocyclic ligand group.     

Partially substituted lithium manganese oxides as 3 V cathode materials for secondary lithium batteries

Low temperature synthesis and electrochemical properties of partially substituted lithium manganese oxides are reported. We demonstrate various metallic cations (Cu²⁺, Ni²⁺, Fe³⁺, Co³⁺) can be incorporated in the 3 V layered cathodic material Li_0.45MnO_2.1. New compounds Li_0.45Mn_0.88Fe_0.12O_2.1, Li_0.45Mn_0.84Ni_0.16O_2.05, Li_0.45Mn_0.79Cu_0.21O_2.3, Li_0.45Mn_0.85Co_0.15O_2.3 are prepared. These 3 V cathode materials are characterized by the same shape of discharge-charge profiles but different values of the specific capacity, between 90 mAh g⁻¹ and 180 mAh g⁻¹. The best results in terms of capacity and cycle life are obtained with the selected content of 0.15 Co per mole of oxide, as the optimum composition. The high kinetics of Li⁺ transport in Li_0.45Mn_0.85Co_0.15O_2.3 compared to that in the Co-free material is consistent with a substitution of Mn(III) by Co(III) in MnO₂ sheets.     

Cleavage of Qinghaosu (Artemisinin) Induced by Non‐Iron Transition‐Metal Ions in the Presence of Excess Cysteine

In the presence of an excess of cysteine, a catalytic amount of a non‐iron transition‐metal ion (Co²⁺, Cu²⁺, Ni²⁺, Ti⁴⁺, and Mn²⁺) may also induce cleavage of qinghaosu (artemisinin; 1 ) to give those end products previously reported for Fe²⁺‐mediated degradation.     

Synthesis and Characterization of a Dinuclear Nitrogen‐Rich Ferrocenyl Ligand and Its Ionic Coordination Compounds and Their Catalytic Effects During Combustion

Alkylferrocene‐based burning‐rate catalysts (BRCs) exhibit distinct migration tendency and high volatility and thus result in inferior performance of composite solid propellants during their combustion processes. To deal with these drawbacks, a novel dinuclear nitrogen‐rich ferrocene derivative, 4‐amino‐3,5‐bis(4‐ferrocenyl‐1,2,3‐triazolyl‐1‐methyl)‐1,2,4‐triazole (BFcTAZ) and its twenty seven ionic coordination compounds, [M₂(BFcTAZ)₂(H₂O)₄]_mX_n·xH₂O (M = Cr³⁺, Mn²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺ and Pb²; X = polycyano anions), were synthesized and characterized by FT‐IR, UV/Vis, and elementary analysis. Crystal structure of BFcTAZ was further confirmed by single‐crystal X‐ray diffraction and a general molecular structure of the new complexes was proposed. Their high thermal stability was verified by TG technique. Cyclic voltammetry studies suggested that the new compounds are diverse redox systems. Their effects on the thermal degradation of some common oxidizers were measured by DSC technique. The results indicated that most of the new complexes exert great effects on the thermal decomposition of AP, RDX, and 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7) and some of them are more active than catocene. The Cu²⁺ complexes are among the excellent ones. However, only six compounds have appreciable catalytic activity in the thermal degradation of HMX.     

Effect of eluent composition and pH and chemiluminescent reagent pH on ion chromatographic selectivity and luminol-based chemiluminescence detection of Co, Mn and Fe at trace levels

The alkaline-luminol/H₂O₂-based chemiluminescent (CL) detection of Fe²⁺, Co²⁺, and Mn²⁺, separated with a Dionex CS5A ion chromatographic phase was studied by means of a multi-pump flow system allowing the variation of the post-column solution composition. A perchlorate gradient at pH 1.9 (with HCl) was used to separate cations partially complexed with 5.6 mM oxalate present in the eluent and necessary for the chosen separation phase. A 0.91 mM luminol, 3.3 mM H₂O₂ in 0.25 M carbonate buffer at pH 10.5 composition was chosen as CL reagent solution. The chosen pH value warrants signal repeatability and wider linearity range although absolute signal is not maximum. The CL signal was related to the pH of the two post-column mixing solutions. Calibration plots of Co²⁺ and Fe²⁺ were linear in the chosen concentration range whilst a parabolic model was the best fit for Mn²⁺. Detection limits were 0.24, 0.50 and 375 nM for Co²⁺, Fe²⁺ and Mn²⁺, respectively. The method was used to determine Co²⁺ at trace level in commercial copper chelates used for animal feeding. A comparison with a chromatographic method with spectrophotometric detection was made giving results comparable both in absolute values and accuracy.