Perchlorate Complexes Research Articles

Cobalt-Imidazole Complexes: Effect of Anion Nature on Thermochemical Properties.

A solvent-free method was proposed for the synthesis of hexaimidazolecobalt(II) nitrate and perchlorate complexes-[Co(C3H4N2)6](NO3)2 and [Co(C3H4N2)6](ClO4)2-by adding cobalt salts to melted imidazole. The composition, charge state of the metal, and the structure of the resulting complexes were confirmed by elemental analysis, XPS, IR spectroscopy, and XRD. The study of the thermochemical properties of the synthesized complexes showed that [Co(C3H4N2)6](NO3)2 and [Co(C3H4N2)6](ClO4)2 are thermally stable up to 150 and 170 °C, respectively. When the critical temperature of thermal decomposition is reached, oxidative two-stage gasification is observed. In this case, the organic component of the [Co(C3H4N2)6](NO3)2 complex undergoes almost complete gasification to form Co3O4 with a slight admixture of CoO, which makes it attractive as a component of gas-generation compositions, like airbags.

Well isolated copper(II) pyrazine-bridged chains: synthesis and magneto-structural analysis of 2-halo-4-pyridone perchlorate complexes

Two new coordination polymers, [Cu(pz)(L)2(H2O)2](ClO4)2 (L = 2-Cl- (1) or 2-Br-4-pyridone (2); pz = pyrazine), have been synthesized and characterized by X-ray diffraction, EPR and variable temperature magnetic measurements. Both compounds crystallize as well isolated pyrazine-bridged chains with the heterocyclic ligands in the pyridone tautomer and coordinated via the oxygen atom. The Cu ions possess Jahn-Teller elongated octahedral geometries with the Jahn-Teller axis along the Cu-O axis. The water molecules in 2 are inequivalent with one molecule semi-coordinate (dCu… O = 3.225(6) Å) at an occupancy of 0.72. Both compounds exhibited axial powder EPR spectra, as expected. Variable temperature magnetic measurements are well fit by the uniform chain Heisenberg antiferromagnetic model with J = −10.74(4) K (1) or = −10.64(2) K (2). Comparison with the known 3-halo-4-pyridone compounds suggests an inverse relationship between the Cu-pz-Cu distance and the strength of the magnetic exchange.

Review of Solvation Studies of Copper (1) Complexes in Different Solvents and at Different Temperatures

The study of the solvation behavior of copper (1) complexes in the mixed solvents has generated a great interest in the field of chemistry. Copper complexes have attracted wide attention due to their important role in analytical chemistry, organic synthesis, metallurgy and medicines etc. Nevertheless, during recent years there has been an increasing interest in the behavior of copper (1) complexes in aqueous and non-aqueous solvents with a view to investigate ion-ion and ion solvent or solute solute interactions under varied conditions. The solvation behavior of some copper(I) perchlorate complexes in binary mixtures of dimethylsulfoxide with dimethylacetamide and dimethylformamide at 298k, and Some Copper(I) Nitrate Complexes in Dimethylsulfoxide and Nitromethane at 298 K and copper sulfate have been measured in binary mixtures of aqueous–methanol mixtures at different temperatures is studied by a combined approach using Molar conductance, ultrasonic velocity and density data, or limiting molar conductance (Λ0), the association constants (KA) respectively . This study is a condensed version of earlier work in the same fields. Keywords: solvation, Molar conductance, Copper sulfate, copper(I) perchlorate

The role of intermolecular interactions in [Fe(X-salEen)2]ClO4 spin crossover complexes.

Two new spin crossover (SCO) Fe(III) compounds were prepared, their structures were analysed and their magnetic properties were investigated. An exhaustive analysis of the effects of halogen substitution and aromatic ring functionalisation on the magnetic properties of non-solvated Fe(III) perchlorate complexes has been performed. Through comparative analysis, different magnetic profiles were found for the compounds studied, namely F (1), Cl (2), H (3), Br (4a, 4b), and I (5). Using tools like Hirshfeld analysis, the study revealed patterns in octahedral distortions and deviations from the ideal octahedral geometry. The SCO phenomenon as the conducting wire in this study, emphasises the influence of intermolecular interactions on the low spin (LS) to high spin (HS) transitions in these halogen-substituted complexes. The prevalence of H⋯H contributions has been demonstrated, albeit being the weakest and an inverse strength relationship in H⋯X interactions ranging from F to I. The findings not only interpret the intricate balance between halogen substitution, functionalisation, and intermolecular interactions in modulating magnetic properties but also direct future works in designing similar molecular systems.

A novel energetic pyridine-2-carbohydrazide copper perchlorate complex: synthesis, cationic ligand structure and properties

The pyridine-2-carbohydrazide copper perchlorate complex was synthesized, and it possessed high thermal stabilitiy and moderate sensitivity which was sensitive to laser and could detonate RDX.

Synthesis of Bridged Tetrazoles with Promising Properties and Potential Applications by a One-Step Finkelstein Reaction.

Numerous nitramine bridged compounds which show promising combinations of properties have already been identified in the area of energetic materials. In this work, four new nitrazapropane bridged tetrazoles, as well as four new trinitrazaheptane tetrazoles and three oxapropane bridged tetrazoles were synthesized and fully characterized. These new compounds can all be synthesized by a simple, one-step synthesis using Finkelstein conditions. All of these new energetic materials were characterized using NMR spectroscopy, single crystal X-ray diffraction, vibrational analysis and elemental analysis. The thermal behaviour of these compounds was studied by differential thermal analysis (DTA) and partly by thermogravimetric analysis (TGA). The BAM standard method was used to determine the sensitivities towards impact (IS) and friction (FS). The enthalpies of formation were calculated at the CBS-4M level, and the energetic performances were calculated using the EXPLO5 (V6.06.01) computer code. The properties of the new compounds were compared to each other as well as to the known energetic material RDX. Moreover, the iron(II) and copper(II) perchlorate complexes with 1,3-bis-1,1-tetrazolylnitrazapropane as ligand were prepared and investigated.

Further Understanding the Roles of Solvent, Brønsted Acids, and Hydrogen Bonding in Iron Porphyrin-Mediated Carbon Dioxide Reduction.

Improving our understanding of how molecules and materials mediate the electrochemical reduction of carbon dioxide (CO2) to upgraded products is of great interest as a means to address climate change. A leading class of molecules that can facilitate the electrochemical conversion of CO2 to carbon monoxide (CO) is iron porphyrins. These molecules can have high rate constants for CO2-to-CO conversion; they are robust, and they rely on abundant and inexpensive synthetic building blocks. Important foundational work has been conducted using chloroiron 5,10,15,20-tetraphenylporphyrin (FeTPPCl) in N,N-dimethylformamide (DMF) solvent. A related and recent report points out that the corresponding perchlorate complex, FeTPPClO4, can have superior function due to its solubility in other organic solvents. However, the importance of hydrogen bonding and solvent effects was not discussed. Herein, we present a detailed kinetic study of the triflate (CF3SO3-) complex of FeTPP in DMF and in MeCN using a range of phenol Brønsted acid additives. We also detected the formation of Fe(III)TPP-phenolate complexes using cyclic voltammetry experiments. Importantly, our new analysis of apparent rate constants with different added phenols allows for a modification to the established mechanistic model for CO2-to-CO conversion. Critically, our improved model accounts for hydrogen bonding and solvent effects by using simple hydrogen bond acidity and basicity descriptors. We use this augmented model to rationalize function in other reported porphyrin systems and to make predictions about operational conditions that can enhance the CO2 reduction chemistry.

Synthesis, Structure and Antimicrobial Activity of New Co(II) Complex with bis-Morpholino/Benzoimidazole-s-Triazine Ligand

A new Co(II) perchlorate complex of the bis-morpholino/benzoimidazole-s-triazine ligand, 4,4′-(6-(1H-benzo[d]imidazol-1-yl)-1,3,5-triazine-2,4-diyl)dimorpholine (BMBIT), was synthesized and characterized. The structure of the new Co(II) complex was approved to be [Co(BMBIT)2(H2O)4](ClO4)2*H2O using single-crystal X-ray diffraction. The Co(II) complex was found crystallized in the monoclinic crystal system and P21/c space group. The unit cell parameters are a = 22.21971(11) Å, b = 8.86743(4) Å, c = 24.38673(12) Å and β = 113.4401(6)°. This heteroleptic complex has distorted octahedral coordination geometry with two monodenatate BMBIT ligand units via the benzoimidazole N-atom and four water molecules as monodentate ligands. The hydration water and perchlorate ions participated significantly in the supramolecular structure of the [Co(BMBIT)2(H2O)4](ClO4)2*H2O complex. Analysis of dnorm map and a fingerprint plot indicated the importance of O···H, N···H, C···H, C···O, C···N and H···H contacts. Their percentages are 27.5, 7.9, 14.0, 0.9, 2.8 and 43.5%, respectively. The sensitivity of some harmful microbes towards the studied compounds was investigated. The Co(II) complex has good antifungal activity compared to the free BMBIT which has no antifungal activity. The Co(II) complex has good activity against B. subtilis, S. aureus, P. vulgaris and E. coli while the free BMBIT ligand has limited activity only towards B. subtilis and P. vulgaris. Hence, the [Co(BMBIT)2(H2O)4](ClO4)2*H2O complex has broad spectrum antimicrobial action compared to the free BMBIT ligand.

The Anion Impact on Dimensionality of Cadmium(II) Complexes with Nicotinamide

Three novel cadmium(II) coordination compounds, the dimeric [Cd(CH3COO)2(nia)2]2 (1), the polymeric {[Cd(nia)4](ClO4)2}n (2), and the monomeric [Cd(H2O)3(nia)3](ClO4)2·nia (3), were prepared in the reactions of the nicotinamide (pyridine-3-carboxamide, nia) with the corresponding cadmium(II) salts. All prepared compounds were characterized by elemental analyses, FT-IR spectroscopy, TGA/DTA, and single crystal X-ray analysis. The impact of anions (acetate, perchlorate) and solvent used on the dimensionality of cadmium(II) complexes and the cadmium(II) coordination environment was investigated. The bridging capabilities of acetate ions enabled the formation of dimers in the crystal structure of 1. It was shown that the dimensionality of perchlorate complexes depends on the solvent used. The coordination polymer 2 is isolated from an ethanol solution, while monomeric compound 3 was obtained by using a water/ethanol mixture as a solvent. The pentagonal-bipyramidal coordination of cadmium(II) was found in the presence of chelating and bridging acetate ions in 1. In the presence of non-coordinating perchlorate anions in 2 and 3, the coordination geometry of cadmium(II) is found to be octahedral. The supramolecular amide-amide homosynthon R22(8) was preserved in the hydrogen-bonded frameworks of all three compounds.

4-Aminoantipyrine Thiosemicarbazone Complexes with cobalt(II): Synthesis, Spectroscopic, Thermal, and Antibacterial Research

An interesting series of cobalt(II) complexes of the new ligands: The antipyrinethiosemicarbazones 4[N-(benzalidene) amino]antipyrinethiosemicarbazone (BAAPTS), 4[N-(2-hydroxy-benzalidene)amino]antipyrinethiosemicarbazone (2b), and 4[N-(2-hydroxy-1-naphthalidene)amino]antipyrinethiosemicarbazone (2c) The complexes were discovered to have the typical stoichiometry [CoX2(H2O)(L)] and [Co(L)2](ClO4)2, where X = Cl, NO3, NCS, or CH3COO, and L =2a, 2b, or 2c. Elemental analyses, molar conductivity measurements, molecular weight estimations, magnetic moments at room temperature, infrared, and electronic spectra were used to describe the complexes. The behaviour of each and every thiosemicarbazone is that of neutral tridentate (N, N, S) donor ligands. The perchlorate complexes are 1:2 electrolytes, but the chloro, nitrato, thiocyanato, and acetate complexes are essentially non-electrolytes, according to the conductivity measurements in PhNO2 solution. Studies on thermodynamic behavior were conducted for a few typical complexes, and a decomposition process was suggested. The cobalt(II) complexes of the ligands and their antibacterial and antifungal activities have also been studied, and it has been found that the complexes are more effective bactericides than the ligands.

Dinuclear Complexes of Uranyl, Neptunyl, and Plutonyl: Structures and Oxidation States Revealed by Experiment and Theory.

Dinuclear perchlorate complexes of uranium, neptunium, and plutonium were characterized by reactivity and DFT, with results revealing structures containing pentavalent, hexavalent, and heptavalent actinyls, and actinyl-actinyl interactions (AAIs). Electrospray ionization produced native complexes [(AnO2)2(ClO4)3]- for An:An = U:U, Np:Np, Pu:Pu, and Np:Pu, which are intuitively formulated as actinyl(V) perchlorates. However, DFT identified lower-energy structures [(AnO2)(AnO3)(ClO4)2(ClO3)]- comprising a perchlorate fragmented to ClO3, actinyl(VI) cation AnVIO22+, and neutral AnO3. For U:U and Np:Np, and Np in Np:Pu, the coordinated AnO3 is calculated as actinyl(VI) with an equatorial oxo, [Oyl═AnVI═Oyl][═Oeq], whereas for Pu:Pu, it is plutonyl(V) oxyl, [Oyl═PuV═Oyl][-Oeq•]. The implied lower stability of PuVI versus NpVI indicates weaker Pu═Oeq versus Np═Oeq bonding. Adsorption of O2 by the U:U complex suggests oxidation of UV to UVI, corroborating the assignment of perchlorate [(AnVO2)2(ClO4)3]-. DFT predicts the O2 adducts are [(AnVIO2)(O2)(AnVIO2)(ClO4)3]- with actinyls oxidized from +V to +VI by bridging peroxide, O22-. In accordance with reactivity, O2- addition is computed as substantially exothermic for U:U and least favorable for Pu:Pu. Collision-induced dissociation of native complexes eliminated ClO2 to yield [(AnO2)(O)2(AnO2)(ClO4)2]-, in which fragmented O atoms bridge as oxyl O-• and oxo O2- to yield uranyl(VI) and plutonyl(VI), or as oxos O2- to yield neptunyl(VII), [Oyl═NpVII═Oyl]3+.

Structural elucidation, in vitro DNA binding and anticancer investigations of a new specific target dinuclear Zn(II) complex

In this study, dinuclear bis(2,2′-bipyridine)-tris{[μ-pyrimidin-2-yl)sulfanyl]acetato}Zn(II) perchlorate complex was synthesized and characterized by FT-IR, ESI-MS, 1H NMR and single-crystal X-ray diffraction studies. The bis(2,2′-bipyridine)-tris{[μ-pyrimidin-2-yl)sulfanyl]acetato}Zn(II) perchlorate was crystallized in a monoclinic crystal system having a P 21/c space group. The single-crystal structure of bis(2,2′-bipyridine)-tris{[μ-pyrimidin-2-yl)sulfanyl]acetato}Zn(II) perchlorate reveals that Zn1 is five coordinated and has adopted distorted square pyramidal geometry while as Zn2 centre is six coordinated and has adopted distorted octahedral geometry, bridged by three carboxylate groups of (2-pyrimidylthio) acetic acid (PTAA). Hirshfeld surface analysis and density functional theory were determined by crystallographic computational tools to investigate the contribution of non-covalent interactions, reactivity and stability of bis(2,2′-bipyridine)-tris{[μ-pyrimidin-2-yl)sulfanyl]acetato}Zn(II) perchlorate. In vitro, ct-DNA binding studies of the complex were accomplished by applying various spectroscopic and analytical techniques. The results obtained suggested a groove or electrostatic mode of binding. The bis(2,2′-bipyridine)-tris{[μ-pyrimidin-2-yl)sulfanyl]acetato}Zn(II) perchlorate has caused significant double-stranded scission of pBR322 DNA through the hydrolytic pathway as observed by the gel electrophoretic experiment. Cytotoxicity of bis(2,2′-bipyridine)-tris{[μ-pyrimidin-2-yl)sulfanyl]acetato}Zn(II) perchlorate was evaluated against MCF-7, MDA-MB-231, Hop-62, AW13516 and SiHa human cancer cell lines, which revealed a moderate anticancer response. In addition, binding studies of the bis(2,2′-bipyridine)-tris{[μ-pyrimidin-2-yl)sulfanyl]acetato}Zn(II) perchlorate with BSA protein were performed by fluorescence spectroscopy. The synchronous fluorescence spectra suggested the efficient binding of complex towards tyrosine than tryptophan. The quenching mechanism of BSA by complex was found static in nature.

Ag(I)‐mediated hydrolysis of hydrazone to azine: Synthesis, X‐ray structure, and biological investigations of two new Ag(I)‐azine complexes

AbstractReactions of 2‐(1‐hydrazonoethyl)pyridine with silver salts AgX (X = NO3¯ or ClO4¯) proceeded via the hydrolysis of the pyridine ligand and the formation of the dinuclear [AgL1]2(ClO4)2 (1) and [AgL1(NO3)]2 (2) complexes of the azine ligand, 1,2‐bis(1‐(pyridin‐2‐yl)ethylidene)hydrazine (L1). The structures of the obtained complexes were determined by single crystal X‐ray diffraction. The azine ligand (L1) is acting as a bidentate ligand and connects the two Ag‐sites via the pyridine and the azine nitrogen atoms. In complex 1, the Ag(I) ion is tetra‐coordinated, while in complex 2 the Ag(I) ion is penta‐coordinated due to the presence of additional interaction with one of the oxygen atoms of the nitrate ion. As a result, the azine ligand is significantly twisted in complex 2 compared to complex 1. The optimized geometries of three conformers of L1 were calculated using DFT calculations, and their kinetic and thermodynamic stability were analyzed. It was found that a free rotation of L1 is required prior to the chelation of the Ag(I) ion. The packing in complex 1 is controlled by H…H, O…H, and Ag…O interactions, but in complex 2, the O…H and N…H interactions are the most significant. Complex 2 has better antifungal activity against Aspergillus fumigatus and Candida albicans than the antifungal drug Ketoconazole. Also, the nitrato complex 2 has a promising antioxidant activity compared to the perchlorate complex 1. The cytotoxicity against colon carcinoma HCT‐116 cell line is higher for complex 1 (IC50 = 19.72 ± 0.94 μg/ml) than complex 2 (IC50 = 68.31 ± 2.97 μg/ml).

Solvate Ionic Liquids: Assessing the Possibility of Determining the Composition by Means of Gas–Liquid Chromatography

A study is performed of the possibility of using gas–liquid chromatography (GLC) to determine the composition of solutions of lithium salts in aprotic dipolar solvents and solvate ionic liquids. The objects of study are solutions of lithium perchlorate and lithium trifluoromethanesulfonate in sulfolane and solvate complexes of lithium perchlorate with sulfolane obtained in two ways: direct interaction of the initial components in a given molar ratio and interaction of the components in a common solvent with its subsequent removal via evaporation. It is shown that GLC is a convenient way of determining the content of a solvating solvent in the composition of solutions and solvate ionic liquids. The presence of lithium salt in the analyzed solutions does not affect the period of retention; instead, it raises the degree of asymmetry of the chromatographic peak of the solvent and manifestation of the tailing effect. It is found that the presence of salt in the considered system also does not reduce the accuracy of determining the solvent content. The error in determining the content of solvent in solutions of lithium salts and solvate complexes by GLC is no greater than 1%.

Synthesis, characterization, X-ray crystal structure and Hirshfeld surface analysis of Ni(II) complex of 1,2-bis(pyridin-2-ylmethylene)hydrazine

We report the synthesis, characterization, X-ray crystal structure and Hirshfeld surface analysis of Ni(II) perchlorate complex (1, Ni2L3·4ClO4·2CH3CN) of 1,2-bis(pyridin-2-ylmethylene)hydrazine (L) ligand. The X-ray crystallographic study of complex 1 reveals that in the presence of Ni(II) ions,the ligand L forms a dimeric triple helix with a Ni(II)-Ni(II) distance of 3.794 Å. Crystal data for C40H36Cl4N14Ni2O16: Monoclinic, space group P21/c (no. 14), a = 20.7558(19) Å, b = 13.1937(12) Å, c = 20.0181(18) Å, β = 96.9510(10)°, V = 5441.6(9) Å3, Z = 4, T = 293.15 K, μ(MoKα) = 0.965 mm-1, Dcalc = 1.498 g/cm3, 38075 reflections measured (1.976° ≤ 2Θ ≤ 43.728°), 6557 unique (Rint = 0.0695, Rsigma = 0.0466) which were used in all calculations. The final R1 was 0.0518 (I > 2σ(I)) and wR2 was 0.1270 (all data). The Hirshfeld surface analysis of complex 1 shows that C···H, H···H, N···H and O···H interactions of 10.9, 26.4, 6.7, and 33.4%; respectively, which exposed that the main intermolecular interactions were H···H intermolecular interactions.

Synthesis and characterization of bis-tridentate group 12 perchlorate complexes of bis(2-pyridylmethyl) ether

Bis-tridentate chelates of Zn(ClO4)2, Cd(ClO4)2, and Hg(ClO4)2 with two equivalents of bis(2-pyridylmethyl) ether (L1) were isolated. The complexes were characterized using X-ray crystallography, IR, 1H NMR, and TGA. Isomorphs [Zn(L1)2](ClO4)2·CH3CN (1·CH3CN) and [Cd(L1)2](ClO4)2·CH3CN (2·CH3CN) crystallized in the monoclinic space group P21 with meridional octahedral geometry. [Hg(L1)2](ClO4)2 (3) crystallized in the monoclinic space group P21/c with approximately C2 symmetric trigonal prismatic geometry. Proton NMR of 3 at −40 °C revealed heteronuclear JHgH coupling yet lacked the geminal splitting of methylene protons expected from the solid-state structure suggesting equivalence through intramolecular reorganization was rapid relative to the NMR time scale. The complexes are compared to other bis-tridentate chelates of bis(2-pyridylmethyl) ligands with the central oxygen of L1 replaced by other heteroatoms.

Copper(II) perchlorate complexes with antipyrine: synthesis, structure, cytotoxicity and DFT calculations

The synthesis, structure and properties of copper(II) perchlorate complexes with antipyrine (AP), [Cu(AP)4(H2O)](ClO4)2 and [Cu(AP)5](ClO4)2, are described and compared with those of alternative compounds containing different AP ligands.

Studying the Composition of Solvate Complexes of Lithium Perchlorate with Sulfolane via Vacuum Gravimetry

Studying the Composition of Solvate Complexes of Lithium Perchlorate with Sulfolane via Vacuum Gravimetry

Photoprocesses in bis(15-crown-5)-1,3-distyrylbenzene and its complexes with metal perchlorates

Photoprocesses in bis(15-crown-5)-1,3-distyrylbenzene (DSB) and its complexes with barium and lead perchloatewere studied in MeCN by absorption, luminescence, and laser kinetic spectroscopy. The triplet DSB molecules are involved in the degradation of electronic excitation energy, together with fluorescence processes. The most efficient intersystem crossing accompanied by a decrease in the DSB fluorescence quantum yield, occurs for the lead perchlorate complex. Using quantum chemistry methods (DFT and TDDFT), the geometry, structure, and transition energies to the S1 state were calculated for trans- and cis-isomers of DSB in the gas phase and with allowance for the solvent and for 1:1 and 2:2 DSB complexes with barium cation in the ground and excited states. The orbital structures of the 2:2 complexes were calculated by ab initio method, and conclusions were drawn about the possibility of [2 + 2]- photocycloaddition reaction.

Crystal Structure and Properties of an Energetic Perchlorate Complex Compound with Copper and Cytosine

AbstractA coordination compound from copper(II) perchlorate with cytosine was synthesized. The molecule contains copper(II) cation, four cytosine ligands, and two perchlorate anions. The single crystals of the compound were grown from the methanol solution. The crystal structure was determined by single‐crystal X‐ray diffraction. The compound crystallizes in the orthorhombic system (Pbcn space group) with crystal parameters: a=19.454(2) Å, b=10.185(2) Å, c=13.604(1) Å, V=2695.83(5) Å3, Z=4, and F(000)=1508 as a solvate with one methanol molecule in the asymmetric unit. It was characterized with elemental analysis, differential scanning calorimetry (temperature of decomposition – 270.1 °C), differential thermal analysis, infrared spectroscopy. Small‐scale safety testing was done to determine the impact and friction sensitivity. The title compound has sensitivity typical to secondary explosives (7.5 J, 230 N). Measured density and enthalpy of formation were used to calculate detonation parameters. With detonation velocity and pressure of 6132 m/s and 14.6 GPa, respectively, it has the moderate performance.