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The present study reports a physico-chemical characterization of the solutions of n-butylammonium perchlorate (C4H9NH3ClO4) (BAP) in acetonitrile–dimethylsulfoxide (AN–DMSO) binary mixtures. One objective is to optimize the extraction of components from waste propellants, BAP acting as a model compound. Combining the conductometric and viscometric approaches, quantitative analysis of molecular interactions is reported for solutions of BAP in AN–DMSO binary mixtures containing 0, 20, 40, 60, 80 and 100 mol% DMSO at different temperatures. Analysis of the conductance data to obtain limiting molar conductivities was done using the Onsager equation and the viscosity data were analysed using the Jones–Dole equation. From viscosity data, A and B-coefficients, B/VΦ values and the temperature derivative of B-coefficients, (dB/dT) are calculated. Using the appropriate division of limiting molar conductivity and B-coefficients of tetra-n-butylammonium tetraphenylborate (Bu4NBPh4) as a ‘reference’ electrolyte, the limiting ionic conductivities ( $$\lambda_{ \pm }^{{\text{o}}}$$ ) and B±-coefficients for individual ions have been estimated. The conductivity data is further utilized for obtaining different transport properties such as Walden product, solvated radii (rs), solvation numbers (ns), diffusion coefficients (D±) and ionic mobility (µi) of the ions. The influence of the solvent composition on the solvation of ions was discussed in terms of the composition dependence of solvated radii, Walden product, solvation numbers and viscosity B±-coefficients. In the light of all these parameters, the existence of ion–ion and ion–solvent interations in the investigated system has been identified. Eyring transition state theory has also been used to calculate various activation parameters of viscous flow. Results show preferential solvation of butylammonium ( $${\text{C}}_{4} {\text{H}}_{9} {\text{NH}}_{3}^{ + }$$ ) ions by DMSO in the AN rich region and by AN in the DMSO rich region of the solvent mixtures at all the temperatures studied.

The amination of 3,4,5-triamino-1,2,4-triazole with O-tosylhydroxylamine yielded the nitrogen-rich 1,3,4,5-tetraamino-1,2,4-triazolium cation as its tosylate salt. Subsequent metathesis reactions produced energetic salts with various energetic anions, including perchlorate, nitrate, nitrotetrazolate, and bistetrazolate diolate. All energetic salts possess relatively high heats of formation, thermal sensitivities, and detonation velocities and pressures. The prepared energetic salts were characterized chemically using single-crystal X-ray crystallography, elemental analysis, and 1H NMR, 13C NMR, and IR spectroscopy and energetically by measuring their thermal, impact, and friction sensitivities. 15N NMR was carried out on the tosylate salt. Energetic performances were determined by a combined experimental-computational method using calculated heats of formation and experimental crystal densities.

We report the synthesis, single-crystal structure, solid-state ultraviolet-visible-near-infrared spectroscopy, and theoretical calculations on the first trivalent plutonium crown ether inclusion complex, [(H3O)(18-crown-6)][Pu(H2O)4(18-crown-6)](ClO4)4·2(H2O) (denoted as PuIII-18C6). Single-crystal X-ray diffraction reveals that PuIII-18C6 crystallizes in the orthorhombic space group of Pccn, which is assembled by independent ionic pairs including [Pu(H2O)4(18-crown-6)]3+, [(H3O)(18-crown-6)]+, and perchlorate anions. The plutonium atom is fully encapsulated within the cavity of the 18-crown-6, generating a distorted bicapped square antiprism geometry. The theoretical evaluation confirms that weak Pu-O dative bond is involved between PuIII ions with 18-crown-6. This work may deepen the understanding of the host-guest interactions between trivalent transuranic and macrocyclic ligands.

The molecular and crystal structure of 1H-1,2,4-triazolium perchlorate, C2H4N3 +·ClO4 −, was determined as detailed crystallographic data had not been available previously. The structure has monoclinic (P21/m) symmetry. It is of interest in the field of energetic compounds because nitrogen-rich azoles are the backbone of high-density energetic compounds, and salt-based energetic materials can exhibit preferential energy-release behaviour. The bond angles of the 1,2,4-triazolium cation in this study were similar to those of a cationic triazole ring reported previously and were different from those of the neutral triazole ring. This study contributes to the available data that can be used to analyse the relationship between the structures and properties of energetic materials.

The combination of two bidentate Ph2P(O)CH2C(O)N(Alk)-fragments in one molecule via amide nitrogen atom by alkylene bridge has been found to result in marked increase in REE(III) extraction from perchlorate solutions. The stoichiometry of recovered complexes has been determined. The effect of extractant structure, HClO4 concentration in aqueous phase, and organic solvent nature on the efficiency of REE(III) ions extraction into organic phase has been considered.

Herein, three novel sulfonic-functionalized Bronsted acidic ionic liquids containing perchlorate anion counterparts were prepared and well characterized using FTIR, 1H and 13C NMR, Electro-Spray Ionization Mass Spectrometry (ESI-MS), elemental analysis (CHNS) and TG techniques. These ionic liquid catalysts were prepared through simple and ecofriendly procedures and then applied as efficient catalysts with high yields under solvent-free conditions for the synthesis of 4-substituted coumarins through the Pechmann condensation of different phenols and β-ketoesters. Compared to previous works, the proposed method offers several benefits, such as cleaner reactions, decreased reaction times, high yields, and the lack of laborious workup or purification procedures. Particularly, these catalysts make the condensation of less activated phenols feasible. Besides the described benefits, this advanced protocol was applied successfully for the synthesis of coumarins from γ-lactones such as 3-acetyldihydrofuran-2(3H)-one. The simplicity in operation, applicability and feasibility of this protocol for diverse substrates make it an efficient alternative to conventional methods.

Ruthenium half-sandwich complexes [Cp*Ru (diene compound)]+X− containing various commercially available diene compounds as ligands were tested as catalysts for the hydrogenation of diene compounds. Complexes containing acyclic, cyclic, bicyclic dienes, and α,β-unsaturated carboxylic acids and their derivatives as diene ligands were successfully prepared. The anionic part of the complexes (X−) was represented by triflate, perchlorate and tetrafluoroborate ions. Hydrogenations were carried out in homogeneous and heterogeneous arrangements. The desired products with Z-configuration of the double bond were formed with high selectivity (95–99%) in both cases. It was found out that selectivity was influenced neither by the type of diene ligand nor by the type of the anionic part of the complex. The hydrogenation rate was influenced by the type and the size of the diene ligand. The rate of hydrogenation of diene using complexes containing isolated cyclic or bicyclic ligands was the highest. The lowest reaction rates were observed using complexes with acyclic dienes. The influence of the type of the anionic part of the complex on the reaction rate was also studied. The lowest rate of hydrogenation was observed using complexes with tetrafluoroborate anion. The difference in reaction rates using complexes with triflate and perchlorate anions was not significant. This work added important information for the understanding the mechanism of diene hydrogenation using ruthenium half-sandwich complexes.

This work complements our recent discovery of new phases derived from zirconium perchlorate by addition of hydrogen peroxide. Here, we investigate analogous reactions with hafnium perchlorate, which is found to have modifications of the Clearfield-Vaughan tetramer (CVT). For hafnium perchlorate derivatives, we find distorted versions of CVT by X-ray diffraction and study the reaction solutions by SAXS, Raman spectroscopy, and ESI-MS. Furthermore, we investigate mixed Hf-Zr solution and solid phases and find the latter resemble the zirconium family at low Hf concentrations and the hafnium family at higher hafnium contents.

The aggregation of small molecules in aqueous solution is known to be influenced by the ionic strength of the medium; however, the role played by the identity of salt in the phenomenon of small molecule aggregation is rarely investigated. In the present contribution, we have investigated the effect of counter-anions on the aggregation of a popular cationic amyloid sensing probe, Thioflavin-T (ThT), by taking six different anions, viz. chloride, bromide, acetate, iodide, tetrafluoroborate, and perchlorate. Our results clearly indicate that it is not the ionic strength of the medium which solely controls aggregation of small molecules but distinct ions behave distinctly with regard to the organization. In fact, distinct ion effects play a major role in the salt induced organization of fluorophores. Using detailed steady-state emission, time-resolved emission, and ground-state absorption measurements, the optical properties of salt induced aggregates of ThT have been characterized. We have rationalized our observations on the basis of the theory of matching water affinity, which suggests that the matching free hydration energy is a critical aspect for the formation of contact ion pairs, which eventually results in aggregation. In brief, a larger sized anion, perchlorate, has a lower free energy of hydration and forms a suitable contact ion pair, with a larger organic cation, ThT, having weaker hydration. This contact ion-pair formation subsequently leads to the formation of an aggregate assembly which is found to be emissive in nature. Therefore, it is possible to induce aggregation of ThT by selecting the right counterion with the appropriate size, which may help us to evaluate the false positive signals when high ionic strength and specific counterions are present in the sensing matrix.

The extraction of microamounts of REE(III), U(VI), and Th(IV) from HClO4 solutions with solutions of 2,6-bis(diphenylphosphorylmethyl) pyridine N-oxide (I) in 1,2-dichloroethane was studied depending on the HClO4 concentration in the equilibrium aqueous phase. The stoichiometry of the extracted complexes was determined. It was shown that compound I extracts REE(III), U(VI), and Th(IV) from dilute HClO4 solutions with much higher efficiency than from HNO3 solutions. With an increase in the concentration of acids, the magnitude of the “perchlorate” effect upon extraction of REE(III) and U(VI) decreases, and Th(IV) is extracted by compound I from HClO4 solutions with lower efficiency than from HNO3 solutions.

The electrochemical reduction and oxidation of pi-conjugated materials is a ubiquitous characterization tool involving the process of mixed ion-carrier transport. The kinetics of this process is im...

Reaction of copper(II) perchlorate with pyrazine and pyridine-N-oxide produced the coordination polymer catena-[diaqua-μ-pyrazine-bis(pyridine-N-oxide)copper(II)] perchlorate (1) which was characterized by single-crystal X-ray diffraction, EPR and variable temperature magnetic susceptibility measurements. The compound forms well-isolated linear chains, bridged by pyrazine. EPR studies show a rhombic structure with gave = 2.15. The magnetic data are well described by the uniform Heisenberg chain model giving J/kB = −9.6(1) K and show no signs of inter-chain interactions down to 1.8 K [H = −JΣS1S2]. In the course of the synthesis, the related [tetrakis(pyridine-N-oxide)copper(II)] perchlorate complex (2) was also isolated. X-Ray studies confirm the identity of the compound in comparison to the previous literature. EPR studies indicate a rhombic structure, similar to 1, but variable temperature magnetic susceptibility data show no significant magnetic exchange in agreement with the absence of a superexchange pathway in the crystal.

The complexation of styryl dyes 4-[(E)-2-(3,4-dimethoxyphenyl)]-1-ethylpyridinium perchlorate and trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide with cucurbit[n]urils (CBn) (n = 6, 7) in aqueous solutions in the presence of sodium sulfate with a concentration of 0 to 1 mol/L has been studied by stationary and time-resolved optical spectroscopy, electrochemical, and quantum chemical methods. Adding the electrolyte to the solution decomposes 1 : 1 inclusion complexes with the dyes (D+ · CBn) due to competitive formation of complexes of the cavitand with sodium cations: Na+ · CBn and Na+ · CBn · Na+. Their total formation constants have been determined to be β = 2760 and 168 600 M−2 for CB7 and CB6, respectively, which agrees with the results of quantum chemical calculations. At the same time, no evidence of the presence of Na+ · CBn · D+ type complexes has been found in solutions.

N,N-Substituted ditetrazolylalkanes are widely used molecules in the field of coordination chemistry and are known with different alkyl chain lengths. The missing fragment within this row is presented by the elementary methylene-bridged ditetrazoles. The three different isomers (di(tetrazol-1-yl)methane (1,1-dtm, 1), (tetrazol-1-yl)(tetrazol-2-yl)methane (1,2-dtm, 2), and di(tetrazol-2-yl)methane (2,2-dtm, 3)) were synthesized in a convenient one-step reaction. All of them were successfully incorporated as neutral ligands in 15 new energetic coordination compounds (ECC) based on Cu2+ and Ag+ as well as different anions (nitrate, picrate (PA), styphnate (TNR), trinitrophloroglucinate (TNPG), and perchlorate) revealing an extraordinary coordination behavior of the ligands compared to other 5H-ditetrazolylalkanes. All compounds were extensively characterized using single-crystal X-ray diffraction experiments, infrared spectroscopy (IR), elemental analysis (EA), and differential thermal analysis (DTA). Furthermore, the sensitivities were determined using standard techniques, and Hirshfeld surface calculations of the ligands were applied to explain their significant divergences to external stimuli. The ECC possess very good exothermic decomposition temperatures up to 242 °C. The ignition of all colored complexes was tested in laser experiments, and two copper(II) perchlorate compounds showed promising results in classic initiation capability tests using pentaerythritol tetranitrate (PETN).

Molecular relaxation processes in sodium perchlorate NaClO4 and potassium perchlorate KClO4 are studied via Raman spectroscopy. It is found that the structural first-order phase transition in crystalline perchlorates NaClO4 and KClO4 is extended (a diffuse phase transition). The existence of a pre-transition region in the studied perchlorates NaClO4 and KClO4 is revealed.

A novel viologen ligand, 1,1'-bis-(4-carboxybenzyl)-4,4'-bipyridinium- dibromide (H2BpybcBr2), has been synthesized and successfully introduced into cadmium based coordination polymers (CPs) when it reacts with cadmium perchlorate and 5-phenyltetrazole (5-Ph-Ptz) at room temperature. CPs has been characterized with single-crystal X-ray diffraction, powder X-ray diffraction, and thermogravimetric analysis. CP 1 shows high sensitivity to ultraviolet-visible radiation and exhibits the electron-transfer (ET) photochromic properties. Interestingly, CP 1 exhibits photocontrolled luminescence properties during the coloration-decoloration process and can be used to detect ammonia and aniline in solid state.

The totally symmetric stretching mode $$\nu_{1}$$ν1 Ln–(OH2) of the first hydration shells of all the rare earth (RE) ions across the series from lanthanum to lutetium has been measured on dilute aqueous perchlorate solutions at room temperature. An S-shaped relationship has been found between the $$\nu_{1}$$ν1 Ln–(OH2) peak positions and the Ln–(OH2) bond distances of the lanthanide(III) aqua ions. While the light rare earth ions form nona-hydrates, the heavy ones form octa-hydrates and the rare earth ions in the middle of the series show non integer hydration numbers between 9 and 8. A relationship between wavenumber positions $$\nu_{1}$$ν1 Ln–(OH2) and the Ln–(OH2) bond distances of the RE hydrates has been given. Recent quantum mechanical calculations support the given interpretation.

A novel series of Cu(II) complexes with formula M(HLn)(ClO4)2·mH2O [HLn: 13-membered pentaazamacrocyclic ligand resulted from condensation of N,N′-bis(2-aminoethyl)ethane-1,2-diamine, l-tyrosine (HL1)/l-tryptophan (HL2)/l-phenylalanine (HL3) and formaldehyde] were synthesized by one-pot method. Techniques such as ESI–MS, IR, UV–Vis and EPR spectroscopy provided data characterizing the complexes as mononuclear species. The course of thermal decomposition was followed using TG/DSC–MS analysis in air atmosphere. The TG curves showed a gradual decomposition in several stages that comprise dehydration, decomposition of perchlorate ions as well as fragmentation and oxidative degradation of the organic part. The intermediates formed after first stage of water elimination are stable on 40, 15 and 80 °C interval for complexes (1), (2) and (3), respectively. The compounds were tested on the eukaryotic unicellular organism Saccharomyces cerevisiae, showing variable actions in terms of toxicity, cellular uptake and capacity to alleviate growth defects associated with Cu, Zn-superoxide dismutase (SOD1) depletion.

A novel Ni2+ complex with the N 4-donor tripodal ligand bis[(1-methyl-1H-imidazol-2-yl)methyl][2-(pyridin-2-yl)ethyl]amine (L), namely, aqua{bis[(1-methyl-1H-imidazol-2-yl-κN 3)methyl][2-(pyridin-2-yl-κN)ethyl]amine-κN}chloridonickel(II) perchlorate, [NiCl(C17H22N6)(H2O)]ClO4 or [NiCl(H2O)(L)Cl]ClO4 (1), was synthesized and characterized by spectroscopic and spectrometric methods. The crystal structure of 1 reveals an interesting and unusual cocrystallization of isomeric complexes, which are crystallographically disordered with partial occupancy of the labile cis aqua and chloride ligands. The Ni2+ centre exhibits a distorted octahedral environment, with similar bond lengths for the two Ni—N(imidazole) bonds. The bond length increases for Ni—N(pyridine) and Ni—N(amine), which is in agreement with literature examples. The bond lengths of the disordered labile sites are also in the expected range and the Ni—Cl and Ni—O bond lengths are comparable with similar compounds. The electronic, redox and solution stability behaviour of 1 were also evaluated, and the data obtained suggest the maintenance of structural integrity, with no sign of demetalation or decomposition under the studied conditions.

The synthesis and characterization of the N-rich bis(triazole) compound 1H,4′H-[3,3′-bis(1,2,4-triazole)]-4′,5,5′-triamine (C4H7N9) with a N content of 69.6% by weight is reported. The compound exhibits a rich acid–base behavior because it can accept up to two protons, forming a monocation and a dication, and can lose one proton, forming an anion. Measurement of the acid constants has shown that there exist well-defined pH intervals in which each of the four species is predominant in solution, opening the way to their isolation and characterization by single-crystal X-ray analysis as salts with different counterions. Some energetic salts of the monocation or dication containing oxidizing inorganic counterions (dinitramide, perchlorate, and nitrate) were also prepared and characterized in the solid state for their sensitivity. In particular, the neutral compound shows a very remarkable thermal stability in air, with Td = 347 °C, and is insensitive to impact and friction. Salts of the dication with energetic counterions, in particular perchlorate and nitrate, show increased sensitivities and reduced thermal stability. The salt of the monocation with dinitramide as the counterion outperforms other dinitramide salts reported in the literature because of its higher thermal stability (Td = 230 °C in air) and friction insensitiveness., An energetic, N-rich compound that, depending on the pH, can exist as neutral, singly protonated, doubly protonated, and deprotonated species is shown.

In a chlorinative cyclization, Mes-Acr-MeClO4 acted as a visible-light photocatalyst to obtain 3-chlorocoumarins from aryl alkynoates and N-chlorosuccinimide (NCS). The radical initiated reaction proceeded in a cascading manner via Cl- addition to alkynoates. Next, 5-exo-trig spirocyclization and subsequent 1,2-ester migration led to the formation of C-C and C-Cl bonds.

An efficient electrochemical method for benzylic C(sp3)-H bond oxidation has been developed. A variety of methylarenes, methylheteroarenes, and benzylic (hetero)methylenes could be converted into the desired aryl aldehydes and aryl ketones in moderate to excellent yields in an undivided cell, using O2 as the oxygen source and lutidinium perchlorate as an electrolyte. On the basis of cyclic voltammetry studies, 18O labeling experiments, and radical trapping experiments, a possible single-electron transfer mechanism has been proposed for the electrooxidation reaction.

The biological reduction of slow degradation contaminants such as perchlorate (ClO4−) is considered to be a promising water treatment technology. The process is based on the ability of a specific mixed microbial culture to use perchlorate as an electron acceptor in the absence of oxygen. In this study, batch experiments were conducted to investigate the effect of nitrate on perchlorate reduction, the kinetic parameters of the Monod equation and the optimal ratio of acetate to perchlorate for the perchlorate reducing bacterial consortium. The results of this study suggest that acclimated microbial cultures can be applied to treat wastewater containing high concentrations of perchlorate. Reactor experiments were carried out with different hydraulic retention times (HRTs) to determine the optimal operating conditions. A fixed optimal HRT and the effect of nitrate on perchlorate reduction were investigated with various concentrations of the electron donor. The results showed that perchlorate reduction occurred after nitrate removal. Moreover, the presence of sulfate in wastewater had no effect on the perchlorate reduction. However, it had little effect on biomass concentration in the presence of nitrate during exposure to a mixed microbial culture, considering the nitrate as the inhibitor of perchlorate reduction by reducing the degradation rate. The batch scale experiment results illustrated that for efficient operation of perchlorate reduction, the optimal acetate to perchlorate ratio of 1.4:1.0 would be enough. Moreover, these experiments found the following results: the kinetic parameters equivalent to Y = 0.281 mg biomass/mg perchlorate, Ks = 37.619 mg/L and qmax = 0.042 mg perchlorate/mg biomass/h. In addition, anoxic–aerobic experimental reactor results verify the optimal HRT of 6 h for continuous application. Furthermore, it also illustrated that using 600 mg/L of acetate as a carbon source is responsible for 100% of nitrate reduction with less than 50% of the perchlorate reduction, whereas at 1000 mg/L acetate, approximately 100% reduction was recorded.

Seven inorganic salts containing N-phenylbiguanide as a prospective organic molecular carrier of nonlinear optical properties were prepared and studied within our research of novel hydrogen-bonded materials for nonlinear optics (NLO). All seven salts, namely N-phenylbiguanidium(1+) nitrate (C2/c), N-phenylbiguanidium(1+) perchlorate (P-1), N-phenylbiguanidium(1+) hydrogen carbonate (P21/c), bis(N-phenylbiguanidium(1+)) sulfate (C2), bis(N-phenylbiguanidium(1+)) hydrogen phosphate sesquihydrate (P-1), bis(N-phenylbiguanidium(1+)) phosphite (P21), and bis(N-phenylbiguanidium(1+)) phosphite dihydrate (P21/n), were characterised by X-ray diffraction (powder and single-crystal X-ray diffraction) and by vibrational spectroscopy (FTIR and Raman). Two salts with non-centrosymmetric crystal structures—bis(N-phenylbiguanidium(1+)) sulfate and bis(N-phenylbiguanidium(1+)) phosphite—were further studied to examine their linear and nonlinear optical properties using experimental and computational methods. As a highly SHG-efficient and phase-matchable material transparent down to 320 nm and thermally stable to 483 K, bis(N-phenylbiguanidium(1+)) sulfate is a promising novel candidate for NLO.

CuI complexes containing the bulky dialkylbiarylphosphane 2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl ( t BuXPhos, L) and an ancillary ligand (Cl−, Br−, I−, MeCN, ClO4 − or SCN−) have been structurally characterized, namely, chlorido[2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κP]copper(I), [CuCl(C29H45P)], 1, bromido[2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κP]copper(I), [CuBr(C29H45P)], 2, [2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κP]iodidocopper(I), [CuI(C29H45P)], 3, (acetonitrile-κN)[2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κP]copper(I) hexafluoridophosphate, [Cu(CH3CN)(C29H45P)]PF6, 4, [2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κP](perchlorato-κO)copper(I), [Cu(ClO4)(C29H45P)], 5, and di-μ-thiocyanato-κ2 S:N;κ2 N:S-bis{[2-(di-tert-butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κP]copper(I)}, [Cu2(NCS)2(C29H45P)2], 6. Iodide complex 3 shows significant CuI–arene interactions, in contrast to its chloride 1 and bromide 2 counterparts, which is attributed to the weaker interaction between the iodide ion and the CuI centre. When replacing iodide with an acetonitrile (in 4) or perchlorate (in 5) ligand, the reduced interaction between the CuI atom and the ancillary ligand results in stronger CuI–arene interactions. No CuI–arene interactions are observed in dimer 6, due to the tricoordinated CuI centre having sufficient electron density from the coordinated ligands.

Lipid membranes are a key component of contemporary living systems and are thought to have been essential to the origin of life. Most research on membranes has focused on situations restricted to ambient physiological or benchtop conditions. However, the influence of more extreme conditions, such as the deep subsurface on Earth or extraterrestrial environments are less well understood. The deep subsurface environments of Mars, for instance, may harbor high concentrations of chaotropic salts in brines, yet we know little about how these conditions would influence the habitability of such environments for cellular life. Here, we investigated the combined effects of high concentrations of salts, including sodium and magnesium perchlorate and sulfate, and high hydrostatic pressure on the stability and structure of model biomembranes of varying complexity. To this end, a variety of biophysical techniques have been applied, which include calorimetry, fluorescence spectroscopies, small-angle X-ray scattering, dynamic light scattering, and microscopy techniques. We show that the structure and phase behavior of lipid membranes is sensitively dictated by the nature of the salt, in particular its anion and its concentration. We demonstrate that, with the exception of magnesium perchlorate, which can also induce cubic lipid arrangements, long-chain saturated lipid bilayer structures can still persist at high salt concentrations across a range of pressures. The lateral organization of complex heterogeneous raft-like membranes is affected by all salts. For simple, in particular bacterial membrane-type bilayer systems with unsaturated chains, vesicular structures are still stable at Martian brine conditions, also up to the kbar pressure range, demonstrating the potential compatibility of environments containing such ionic and pressure extremes to lipid-encapsulated life.

A new cyanide-bridged FeIII–MnII heterobimetallic coordination polymer (CP), namely catena-poly[[[N,N′-(1,2-phenylene)bis(pyridine-2-carboxamidato)-κ4 N,N′,N′′,N′′′]iron(III)]-μ-cyanido-κ2 C:N-[bis(4,4′-bipyridine-κN)bis(methanol-κO)manganese(II)]-μ-cyanido-κ2 N:C], {[FeMn(C18H12N4O2)(CN)2(C10H8N2)2(CH3OH)2]ClO4} n , (1), was prepared by the self-assembly of the trans-dicyanidoiron(III)-containing building block [Fe(bpb)(CN)2]− [bpb2− = N,N′-(1,2-phenylene)bis(pyridine-2-carboxamidate)], [Mn(ClO4)2]·6H2O and 4,4′-bipyridine, and was structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography and powder X-ray diffraction (PXRD). Single-crystal X-ray diffraction analysis shows that CP 1 possesses a cationic linear chain structure consisting of alternating cyanide-bridged Fe–Mn units, with free perchlorate as the charge-balancing anion, which can be further extended into a two-dimensional supramolecular sheet structure via inter-chain π–π interactions between the 4,4′-bipyridine ligands. Within the chain, each MnII ion is six-coordinated by an N6 unit and is involved in a slightly distorted octahedral coordination geometry. Investigation of the magnetic properties of 1 reveals an antiferromagnetic coupling between the cyanide-bridged FeIII and MnII ions. A best fit of the magnetic susceptibility based on the one-dimensional alternating chain model leads to the magnetic coupling constants J 1 = −1.35 and J 2 = −1.05 cm−1, and the antiferromagnetic coupling was further confirmed by spin Hamiltonian-based density functional theoretical (DFT) calculations.

[Rh(α-NaiR)2Cl2]ClO4 (2) (α-NaiR (1), 1-alkyl-2-(naphthyl-α-azo)imidazoles, R = Me (a), Et (b)) complexes react with ArNH2 (where Ar = X C6H4 , X = H (3), Me (4), Cl (5)) to synthesize the naphthyl appended C N fused bis-[1-alkyl-2-{(7-imidoaryl)naphthyl-α-azo}imidazole-N,N′,N″]rhodium(III)perchlorate complexes [Rh(α-NaiR N Ar)2]ClO4 (3–5). The single crystal X-ray diffraction measurements of one of the complexes, [Rh(α-NaiEt N C6H5)2]ClO4 (3b), confirms the structure. The absorption spectra of the complexes 3–5 show high intense broad multiple transitions at 650–800 nm compared to the transition of the precursor 2 at 500 nm and DFT computations have assigned this transition to an admixture of LLCT (ligand-to-ligand charge transfer, imidoaryl → azonaphthyl) and LMCT transitions. The cyclic voltammogram shows a quasireversible oxidation at >0.8 V, which is assigned by DFT computation to oxidation of the imidoaryl chelate, along with azo reductions at

Molecular relaxation processes in potassium perchlorate KClO4 are studied using Raman spectroscopy. The first-order structural phase transition in crystalline perchlorate KClO4 is shown to be temperature-extended. The presence of a pretransition region in the studied perchlorate KClO4 is reported.

The synthesis of a new silver(I) complex, [Ag(4Brpyz)2ClO4], (where 4Brpyz = 4-bromopyrazole) has been described. Its structural aspects were identified using elemental analysis, IR and 1H NMR spectroscopy, as well as single crystal X-ray diffraction. The crystallographic analysis revealed that the complex crystallizes in the centrosymmetric monoclinic space group P2(1)/c with one [Ag(4Brpyz)2ClO4] complex per asymmetric unit and Z = 4. The asymmetric unit is comprised of one Ag(I) ion, two units of 4Brpyz as an organic ligand and one disordered perchlorate anion (part A: 28.0% and part B: 72.0%). In part A, the structure of the complex is better described as one dimensional coordination polymer, [Ag(4Brpyz)2ClO4]n, where the perchlorate ions act as a connector between the [Ag(4Brpyz)2]+ units and are also included in N H…O hydrogen bonding interactions. On other hand, the major part (B) could be described as an ionic complex of the formula [Ag(4Brpyz)2]ClO4, where the free perchlorate anions are included in N H…O and C H…O hydrogen bonding interactions. The intermolecular interactions and the Ag N/Ag O coordinate bonds were analyzed using Hirshfeld and DFT analyses, respectively. The antimicrobial activity of the complex was compared with that of the free ligand and four commercially available antibiotics. The studied Ag(I) complex showed a lower MIC and hence better reactivity against bacteria and fungus compared to either the free ligand or any of the tested antibiotics.

Heating the solutions of Mn(II), Cd(II) salts and thieno[3,2-b]thiophene-2,5-dicarboxylic acid (H2[3,2-b]ttdc) in N,N-dimethylformamide (DMF) or N,N-dimethylacetamide (DMA) results in the formation of crystalline complex compounds [Mn2([3,2-b]ttdc)2(dmf)2]·4DMF (1), [Cd2([3,2-b]ttdc)2(dmf)2]·2DMF (2), and [Mn2([3,2-b]ttdc)2(dma)2]·2[Mn(dma)6](ClO4)2 (3). According to the X-ray diffraction data, the compounds are two-dimensional layered coordination polymers with square network topologies. In compounds 1 and 2 the layers are shifted relative to each other, while in 3 the layers are located exactly one above another to form extended 9.5×13.0 A channels occupied by solvated [Mn(dma)6]2+ complex cations and perchlorate ClO 4 − anions located mainly near thienothiophene groups.

The one-pot reaction of N,N′-bis(3-methoxysalicylidene)-1,4-diaminobutane (MeOsalbnH2), zinc(II) perchlorate, and lanthanide(III) acetate by a molar ratio of 2:2:1 affords a heterotrinuclear Zn2Ln (Ln: La, Sm, Eu, Tb) complex formulated as [Ln(CH3COO)2{Zn(MeOsalbn)}2]ClO4. In this complex, the central Ln(III) atom is bridged by two {Zn(MeOsalbn)} units and two acetate ligands to form ten-coordination environment. Each Zn(II) atom is coordinated by MeOsalbn2− through the N2O2 site and one oxygen atom from the bridging acetate to afford a five-coordination geometry. In the crystalline state at room temperature, the La(III) complex exhibits a bright blue fluorescence, while the Sm(III) complex shows a reddish-orange colored f–f photoluminescence via an energy transfer from the T1 state localized on the {Zn(MeOsalbn)} units to the acceptor level of the central Sm(III) ion. The results of TD-DFT calculations show that the lowest excited singlet state or triplet state involved in photoluminescence of the La(III) or Sm(III) complex has some intramolecular charge-transfer (CT) character from the phenoxo or methoxy groups to the imino groups in the coordinated MeOsalbn2− moieties.

The coordination chemistry of (diphenyl((5-phenyl-1H-pyrazol-3-yl)methyl) phosphine oxide), 1, was explored. Reacting appropriate equivalents of this ligand and either cobalt perchlorate or MoO2Cl2 results in formation of [Co((C6H5)2POCH2(C3N2H2)(C6H5))2(C4H8O)2][ClO4]2, 2, and MoO2Cl2((C6H5)2POCH2(C3N2H2)(C6H5))(THF), 3. Complexes were characterized by FTIR, NMR, TGA and elemental analyses. Single crystal X-ray spectroscopy reveals octahedral geometries for both compounds. Complex 2 consists of two trans THF ligands in axial positions and two (diphenyl((5-phenyl-1H-pyrazol-3-yl)methyl) phosphine oxide) ligands occupying equatorial positions resulting in an overall octahedral geometry. Two perchlorate counter anions complete the structure. The Co ion resides on an inversion point. THF contains disorder with the four carbon atoms and the major orientation refined to an occupancy of 86.1(9)%. Complex 3 consists of the cis-dioxo MoO2 unit bonded with axial trans-chloride ligands and 1 in the equatorial plane completing the disordered octahedral geometry. A THF ligand is hydrogen bonded to the H-atom on the nitrogen of the pyrazole moiety in ligand 1. DFT calculations based on geometries obtained crystallographically were useful in assigning FTIR peaks and the UV-vis spectra.

Two new one-dimensional (1D) coordination polymers (CPs), namely catena-poly[[[aquacadmium(II)]-bis(μ-4b,5,7,7a-tetrahydro-4b,7a-epiminomethanoimino-6H-imidazo[4,5-f][1,10]phenanthroline-6,13-dione)] bis(perchlorate) dihydrate], {[Cd(C14H10N6O2)2(H2O)](ClO4)2·2H2O} n or {[Cd(BPG)2(H2O)](ClO4)2·2H2O} n , 1, and catena-poly[[lead(II)-bis(μ-4b,5,7,7a-tetrahydro-4b,7a-epiminomethanoimino-6H-imidazo[4,5-f][1,10]phenanthroline-6,13-dione)] bis(perchlorate) dihydrate], {[Pb(C14H10N6O2)2](ClO4)2·2H2O} n or {[Pb(BPG)2](ClO4)2·2H2O} n , 2, have been synthesized using bipyridine–glycoluril (BPG; systematic name: 4b,5,7,7a-tetrahydro-4b,7a-epiminomethanoimino-6H-imidazo[4,5-f][1,10]phenanthroline-6,13-dione), a urea-fused tecton, in a mixed-solvent system. The CdII ion in 1 is heptacoordinated and the PbII ion in 2 is hexacoordinated, with the CdII ion adopting a pentagonal bipyramidal geometry and the PbII ion adopting a distorted octahedral geometry. Both CPs form infinite linear chain structures which are hydrogen bonded to each other leading to the formation of three-dimensional supramolecular network structures. Topological analysis of CPs 1 and 2 reveals that the structures exhibit 1D chain-like arrangements in an AB–AB sequence and shows platonic uniform 2-connected uninodal topologies. Furthermore, a comparative analysis of a series of structures based on the BPG ligand indicates that the size of the metal ion and the types of counter-ions used have a great influence on the resulting frameworks and properties.

The reaction of lithium perchlorate salt and 18-crown-6 (18C-6) in the commercial tetrahydrofuran (THF) solvent leads to a novel important intermediate Li(18C-6)(H2O)2(ClO4)⋅0.5((18C-6)⋅THF) (1). The crystal structure shows it as a mononuclear lithium complex, and the asymmetric unit contains a Li(H2O)2(18C-6) moiety, one half of the 18C-6 guest molecule, one half of the disordered THF solvent molecule, and a perchlorate anion. Solid-state photoluminescence experiments show that complex 1 emits violet luminescence, and its possible emission mechanism is investigated in detail based on theoretical calculations.

© 2019 Elsevier B.V. In this work two new perchlorate based inorganic salts with N-methylformamide (NMF) as a crystal solvate, Cu(ClO 4 ) 2 ·4NMF and Ni(ClO 4 ) 2 ·6NMF were synthesized and their structures confirmed by X-ray analysis. The influence of water content on absorption spectra M(ClO 4 ) 2 ·xNMF (where M = Co, Ni or Cu) in water ˗ N-methylformamide mixtures was investigated and overall molar absorption coefficients were calculated. Density, viscosity and electrical conductivity measurements of these salts in NMF were performed at the temperature T = 298.15 K, atmospheric pressure and in the concentration range up to ~0.2 mol·dm −3 . All obtained results are compared with those obtained in water. From the calculated volumetric and viscometric parameters, nature of interactions between transition metal ions with peptide bond model system based on NMF were discussed.

Cyclam derivatives and their metal complexes have been found to exhibit an anti-HIV effect and stimulate the activity of stem cells from bone marrow. The strength of their binding to the CXCR4 receptor correlates with anti-HIV and stem-cell activities. Knowledge of the conformation and crystal packing of various macrocyclic metal complexes has become important in developing new effective anti-HIV drugs. The synthesis and preparation of single crystals of a new Cu2+-doped macrocyclic compound, (3,14-diethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane)copper(II) bis(perchlorate)–3,14-diethyl-2,13-diaza-6,17-diazoniatricyclo[16.4.0.07,12]docosane bis(perchlorate) (0.69/0.31), {[Cu(C22H44N4)](ClO4)2}0.69·(C22H46N4 2+·2ClO4 −)0.31, is reported. Characterization by X-ray diffraction analysis shows that the asymmetric unit contains half of a centrosymmetric molecule. The macrocyclic ligand in the compound adopts the most stable trans-III conformation. The Cu—N distances of 2.015 (3) and 2.047 (3) Å are normal, but the long axial Cu—O bond of 2.795 (3) Å may be due to a combination of the Jahn–Teller effect and the strong in-plane ligand field. The crystal structure is stabilized by hydrogen bonding between secondary N—H groups, the N atoms of the macrocycle and the O atoms of the perchlorate anions. Hirshfeld surface analysis with 2D (two-dimensional) fingerprint plots indicates that the main contributions to the crystal packing are from H...H (58.0%) and H...O/O...H (41.9%) interactions. Electron paramagnetic resonance (EPR) properties are also described.

This work consists of the synthesis of seven pyridine based ligands, 2-(3-butyl-1H-pyrazol-5-yl)-pyridine (1), 2-[3-(tert-butyl)-1H-pyrazol-5-yl]-pyridine (2), 2-(3-octyl-1H-pyrazol-5-yl)-pyridine (3), 2-(1-octyl-1H-imidazol-2-yl)pyridine (4), 2-[(1H-pyrazol-1-yl)methyl]pyridine (5), 2-[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]pyridine (6) and 2-[(3-methyl-1H-pyrazol-1-yl)methyl]pyridine (7) which have been made before. We modified some routes and obtained improved yields in most cases. The ligands were fully characterised using 1H and 13C NMR, infrared (IR) spectroscopy, mass spectrometry (ms), elemental analysis (EA) and melting point where appropriate. We managed to grow single crystals of the 2-[(1H-pyrazol-1-yl)methyl]pyridine copper(II) perchlorate complex and solved the structure using single crystal X-ray diffraction. Coordination around the copper(II) centre is pseudo square planar, having two ligands coordinated to the metal ion. Indications are that the extraction stoichiometry using this ligand for copper(II) is also 2:1, L:M. This indicates how these ligands are capable of coordinating to metal ions. All the ligands were then used for the extraction of Ni(II) with and without a synergist, viz., sodium p-dodecylbenzenesulfonate (SDBS). The solvent extraction of only Ni(II) in the absence of synergist produced values from 3% to 15% and values between 69% and 79% with synergist. The competitive extraction of metal ions from a base metal ion mix (Co2+, Ni2+, Zn2+, Cu2+, Pb2+ and Cd2+) produced extraction values of 15%−87% extraction of different metal ions with synergist. Finally, time dependent extraction studies with Ni(II) showed that after 4 h equilibrium was established and in some cases even after 1 h equilibrium had been reached.

Ammonium perchlorate (NH4ClO4) and ammonium dihydrogen phosphate (NH4H2PO4) are investigated through laser ablation/matrix-assisted laser desorption ionization processes, anion photoelectron spectroscopy (PES), and density functional theory calculations. No parent anionic species are observed in the mass spectra of these two energetic species. Instead, abundant fragmentation ions for perchlorate are (NH4ClO4–H2O)− and ClO3– and those for dihydrogen phosphate are (NH4H2PO4–H2O)− and PO3–. Their vertical detachment energies and anionic structures are determined and identified through calculations. (NH4H2PO4–H3O)− is additionally detected through PES. Both NH4ClO4– and NH4H2PO4– parent anions possess a dipole bound extra electron distributed around the H atoms of the NH4 group. Based on the calculations, the fragmentation pathway for loss of H2O from either molecule involves detachment of two hydrogens from NH4 and one O from ClO4 or PO4H2. These current investigation results are compared to those previously...

The structures of three copper-containing complexes, namely (benzoato-κ2 O,O′)[(E)-2-({[2-(diethylamino)ethyl]imino}methyl)phenolato-κ3 N,N′,O]copper(II) dihydrate, [Cu(C7H5O2)(C13H19N2O)]·2H2O, 1, [(E)-2-({[2-(diethylamino)ethyl]imino}methyl)phenolato-κ3 N,N′,O](2-phenylacetato-κ2 O,O′)copper(II), [Cu(C8H7O2)(C13H19N2O)], 2, and bis[μ-(E)-2-({[3-(diethylamino)propyl]imino}methyl)phenolato]-κ4 N,N′,O:O;κ4 O:N,N′,O-(μ-2-methylbenzoato-κ2 O:O′)copper(II) perchlorate, [Cu2(C8H7O2)(C12H17N2O)2]ClO4, 3, have been reported and all have been tested for their activity in the oxidation of D-galactose. The results suggest that, unlike the enzyme galactose oxidase, due to the precipitation of Cu2O, this reaction is not catalytic as would have been expected. The structures of 1 and 2 are monomeric, while 3 consists of a dimeric cation and a perchlorate anion [which is disordered over two orientations, with occupancies of 0.64 (4) and 0.36 (4)]. In all three structures, the central Cu atom is five-coordinated in a distorted square-pyramidal arrangment (τ parameter of 0.0932 for 1, 0.0888 for 2, and 0.142 and 0.248 for the two Cu centers in 3). In each species, the environment about the Cu atom is such that the vacant sixth position is open, with very little steric crowding.

Distribution ratios of trivalent lanthanide ions in extraction reactions may be affected by the denticity of a solvent extraction ligand for entropic reasons. This hypothesis was tested by studying the reactions of extraction of the lanthanides(III) (La, Nd, Eu, Dy, Er and Yb) from perchlorate media into methyl isobutyl ketone (MIBK) with three structurally related malonamide ligands (I – III): 2,2′-[1,2-phenylenebis(methylene)]bis(N,N,N’,N’-tetrabutylmalonamide) (I), 2,2′-[1,4-phenylenebis(methylene)]bis(N,N,N’,N’-tetrabutylmalonamide) (II), and 2-benzyl-N,N,N’,N’-tetrabutylmalonamide (III), the molecules of which contain either two (III) or four (I and II) carbonyl oxygen donor atoms. Ligands I and II are the structural isomers. The extracted species in the reactions with all these ligands have the (1:2) metal-to-ligand stoichiometric ratios. All the extraction reactions are enthalpy-driven and have negative values of the standard molar entropy changes at T = (298–313) K. Since the least exothermic standard molar enthalpy changes of the extraction reactions ( Δ r H ° T ) and the least negative standard molar entropy changes of the reactions ( Δ r S ° T ) were observed for ligand I, it was concluded, that the distribution ratios of the lanthanide(III) ions were the highest in the reactions with I due to the entropic effect, presumably resulting from the difference in the coordination of the extraction ligands with the lanthanide(III) ions.

Three new one- (1D) and two-dimensional (2D) CuII coordination polymers, namely poly[[bis{μ2-4-amino-3-(pyridin-2-yl)-5-[(pyridin-3-ylmethyl)sulfanyl]-1,2,4-triazole}copper(II)] bis(methanesulfonate) tetrahydrate], {[Cu(C13H12N5S)2](CH3SO3)2·4H2O} n (1), catena-poly[[copper(II)-bis{μ2-4-amino-3-(pyridin-2-yl)-5-[(pyridin-4-ylmethyl)sulfanyl]-1,2,4-triazole}] dinitrate methanol disolvate], {[Cu(C13H12N5S)2](NO3)2·2CH3OH} n (2), and catena-poly[[copper(II)-bis{μ2-4-amino-3-(pyridin-2-yl)-5-[(pyridin-4-ylmethyl)sulfanyl]-1,2,4-triazole}] bis(perchlorate) monohydrate], {[Cu(C13H12N5S)2](ClO4)2·H2O} n (3), were obtained from 4-amino-3-(pyridin-2-yl)-5-[(pyridin-3-ylmethyl)sulfanyl]-1,2,4-triazole with pyridin-3-yl terminal groups and from 4-amino-3-(pyridin-2-yl)-5-[(pyridin-4-ylmethyl)sulfanyl]-1,2,4-triazole with pyridin-4-yl terminal groups. Compound 1 displays a 2D net-like structure. The 2D layers are further linked through hydrogen bonds between methanesulfonate anions and amino groups on the framework and guest H2O molecules in the lattice to form a three-dimensional (3D) structure. Compound 2 and 3 exhibit 1D chain structures, in which the complicated hydrogen-bonding interactions play an important role in the formation of the 3D network. These experimental results indicate that the coordination orientation of the heteroatoms on the ligands has a great influence on the polymeric structures. Moreover, the selection of different counter-anions, together with the inclusion of different guest solvent molecules, would also have a great effect on the hydrogen-bonding systems in the crystal structures.

The hydrogenation of alkynes and alkenes using a Shrock-Osborn catalysts was followed in-situ with dissolution dynamic nuclear polarization (dDNP) NMR. Natural abundance and 13C labeled dimethyl acetylenedicarboxylate was hyperpolarized prior to hydrogenation using (1,4-bis{diphenylphosphino}butane)(2,5-norbornadiene) rhodium(I) perchlorate, [Rh(NBD)(DPPB)]ClO4. The increased signal-to-noise ratio of dDNP compared to conventional 13C NMR allowed real-time detection of substrate and products as well as the modeling of the hydrogenation kinetics. The build-up of an intermediate was observed during interruption in hydrogen flow, substantiating the current view of the reaction mechanism. Selective inversion of the carbonyl NMR signal of the substrate was applied to demonstrate unequivocally that the new peak appearing in the spectrum originates from a reaction intermediate. The scope of the dDNP method for following reaction dynamics in real time was further demonstrated by substrate competition experiments.

Photoprocesses in bis(18-crown-6)-1,4-distyrylbenzene (DSB) and its complexes with potassium, barium, and lead perchlorates have been studied in MeCN solutions by absorption, luminescent, and laser kinetic spectroscopy. The DSB molecules in the triplet state participate in the degradation of electron excitation energy, cis–trans isomerization, and fluorescence. The triplet–triplet absorption spectrum has several maximums in the range of 500–700 nm. The most efficient intersystem crossing to the triplet state is observed for the lead perchlorate complex, which is accompanied by a drop in the fluorescence quantum yield and the absence of trans–cis isomerization.

The extraction of microamounts of REE(III), U(VI), and Th(IV) from perchlorate solutions with solutions of tetraphenyl(o-oxyphenylenemethylene)diphosphine dioxide (I) in 1,2-dichloroethane was studied. The stoichiometry of the extractable complexes was determined, and the influence of the aqueous phase composition on the efficiency and selectivity of the extraction of U(VI), Th(IV), and REE(III) into the organic phase was analyzed. In going from nitric to perchloric acid solutions, the efficiency of the extraction of REE(III), U(VI), and Th(IV) with solutions of I considerably decreases, whereas the selectivity of the U(VI)/REE(III) separation increases.

A centrosymmetric square planar bis-ligand copper(II) complex, [Cu(HL)2](ClO4)2, with a potential tetradentate Schiff base, HL = 2-(2-(ethylamino)ethyliminomethyl)-6-ethoxyphenol, containing pendant side arm, has been prepared and characterized by elemental and spectral analysis and single crystal X-ray diffraction studies. The potential tetradentate Schiff base is trapped in its zwitterionic form and shows a bidentate bonding mode. Several weak forces like hydrogen bonding and C H∙∙∙π interactions lead to the formation of supra-molecular architecture. The existence of an anion⋯anion interaction between the perchlorate anions have been analyzed using DFT calculations, the Bader’s theory of atoms-in-molecules (AIM) and the non-covalent interaction index (NCI plot). The O⋯O distance is 2.848(2) A.

The protonation of benzoate and the complexation of uranyl monobenzoate in NaClO4 solutions ranging from 0.1 to 0.5 M were quantitatively investigated by means of ultraviolet–visible (UV–Vis) spectrophotometry. The spectrophotometric study revealed that the uranyl monobenzoate species has a significantly enhanced absorption than that of free uranyl, especially in the UV region. The non-linear regression analysis of the UV–Vis absorption data was the first to calculate the protonation constant of benzoate and the stability constant of uranyl monobenzoate at moderate ionic strength. Based on the SIT (specific ion interaction theory), the protonation constants were extrapolated to the zero ionic strength as log β P ° = 4.21 ± 0.01, and the ion interaction coefficient of the benzoate anion with the sodium cation was determined as e ( Ben - , Na + ) = 0.17 ± 0.05 kg·mol−1. In the same manner, the stability constant of uranyl monobenzoate at zero ionic strength and the ion interaction coefficient of the uranyl monobenzoate cation with perchlorate anion were determined to be log β U ° = 2.91 ± 0.01 and e ( UO 2 B e n + , ClO 4 - ) = 0.22 ± 0.07 kg·mol−1, respectively.

1-Alkyl-2-(arylazo)imidazole (RaaiR/), a bidentate N(azo), N(imidazolyl) chelator, and bis(diphenylphosphino)methane (dppm), a P, P bridger, have been used to prepare phosphino bridged dinuclear-Cu(I) complexes, [Cu(μ-dppm)(RaaiR/)]2(ClO4)2. The structures of the complexes have been established by spectral (UV–Vis, IR, 1H NMR) data and the confirmation has been done in case of [Cu(μ-dppm)(HaaiEt)]2(ClO4)2 by single crystal X-ray diffraction studies. Optical stimulation using UV light (365 nm) in methanol solution of the complexes shows that the coordinated RaaiR/ undergoes trans-to-cis isomerization about N N Ar. The rate of trans-to-cis isomerization varies 1.11 × 10−8−1.89 × 10−8 s−1 and is largely dependent on mass of the photochrome and strain/steric crowding generated about N N bond. Quantum yields (ϕt→c) of trans-to-cis isomerization, 0.0843–0.1421, are calculated and free ligand shows higher ϕ (0.17–0.26) than their complex phase. The cis-to-trans isomerisation is a thermally induced process. The activation energy (Ea) of cis-to-trans isomerisation is calculated by controlled temperature experiment and is found that Ea (ligands) > Ea (complexes).

Reactions of cyclic (alkyl)(amino)carbenes, cAACMe and cAACcy with equimolar quantity of HgX2 salts afforded their corresponding halide bridged dimeric complexes, [cAACMeHgCl(μ-Cl)]2 (1), [cAACcy∙HgCl(μ-Cl)]2 (2), [cAACMe∙HgI(μ-I)]2 (3) and [cAACcy∙HgI(μ-I)]2 (4) (Me = methyl and cy = cyclohexyl). It has been possible to perform stepwise substitution of Br− in [cAACcy∙HgBr(μ-Br)]2 with NO3− leading to the isolation and characterization of the mononitrate species, cAACcy∙HgBr(NO3) (5) and the dinitrate compound [cAACcy∙Hg(NO3)(μ-NO3)]2 (6). The cationic mercury species, [(cAACMe)2Hg(NO3)]+[NO3]‒ (7) has also been synthesized by the reaction of adduct, [cAACMe∙HgBr(μ-Br)]2 with 2 eq. of AgNO3. On reaction of [cAACcy∙HgCl(μ-Cl)]2 (2) with AgClO4, only one chlorine could be substituted by perchlorate resulting in the formation of chlorine bridged dimeric complex, [cAACcy∙Hg(ClO4)(μ-Cl)]2 (8). On performing the reaction between cAACcy and HgCl2 in 2:3 relative stoichiometry, a dicationic mercury species [(cAACyc)2Hg]2+[Hg2Cl6]2‒ (9) was isolated in moderate yield.

The molecular copper complex tetrakis(acetonitrile)copper(I) perchlorate [Cu(CH3CN)4ClO4] (1) was shown to act as a catalyst precursor for the efficient oxidation of benzene to p-benzoquinone (p-BQ) with a percentage selectivity of 60–80% under mild conditions, and produces phenol (PhOH) as a minor product at room temperature. Here, we obtained evidences showing the formation of copper based nanoparticle catalyst (NC) (2) from 1 to be the vital step responsible for its ability to catalyze the conversion of benzene to p-BQ, presumably via double oxidation. Addition of a considerable amount of H2O to the reaction mixture improved the selectivity for forming p-BQ to 84% and/or the conversion efficiency to 98%. In addition, the copper NC easily formed in situ through the oxidation of substrate using H2O2 in CH3CN. After separating the NC from the reaction mixture and recycling them several times, it still maintained comparable catalytic efficiency and selectivity for the conversion of benzene to p-BQ.