Atoms Of Anion Research Articles

Reaction of 1,3-dimethylimidazolium dimethylphosphate with elemental sulfur

Abstract By the methods of MALDI and mass spectroscopy with the detection of positively and negatively charged ions, it was found that the reaction of elemental sulfur and 1,3-dimethylimidazolium dimethylphosphate is accompanied by the opening of the S8 ring. 1H, 13C, 15N and 31P NMR spectroscopy showed that the interaction of S8 and 1,3-dimethylimidazolium dimethylphosphate proceeds exclusively on the oxygen atom of the dimethylphosphate anion carrying a negative charge. Kohn-Sham calculations at B3LYP/STO-3G, B3LYP/6-31G* and B3LYP/6-311G* levels of theory confirmed that the reaction of S8 with dimethylphosphate anion is possible.

Single-atom silver induced amorphization of hollow tubular g-C3N4 for enhanced visible light-driven photocatalytic degradation of naproxen

In this work, a novel strategy for building single-atom silver-induced amorphous graphitic carbon nitride (g-C3N4) with a hollow tubular morphology is developed. By forming a tubular supramolecular gel, silver is successfully isolated by the nitrogen atoms in both melamine and nitrate anions, impeding agglomeration in the subsequent thermal polymerization. The high density of single-atom-dispersed silver (atomic ratio up to 11.6%) selectively breaks the hydrogen bonds in layered g-C3N4, leading to a fully amorphous structure. Silver-induced full amorphization not only enhances the visible light absorption of g-C3N4 but also accelerates charge transfer, endowing the as-prepared photocatalyst having the optimal silver content with 52 times higher surface area specific naproxen (NPX) removal activity than pure g-C3N4. Both density functional theory (DFT) calculations and steric effects are applied to explain the degradation pathway of NPX. The toxicity of NPX is reduced by sufficient irradiation. This work provides useful insights into the design and morphology control of single metal ion-dispersed g-C3N4 for environmental applications.

Accelerator mass spectrometry: a remarkable week in May 1977

During a week in May 1977, solutions were found to the forty-year old problem of radiocarbon dating using mass spectrometry, as well as for the generalized mass spectrometry of measuring the abundances of extremely rare radioactive isotopes, such as long lived 236U. These solutions will be described together with a historical introduction, which points out the inherent advantages of some of the equipment developed for nuclear physics research that led towards the new mass spectrometry. In addition, the further developments, in what later came to be called accelerator mass spectrometry or AMS, can now be seen to have been the need to develop a better understanding of the following problems. (1) The appropriate atomic and molecular ion properties in order to expedite the separation of isobars. (2) The properties of the newer versions of the caesium sputter negative ion source that was hoped would almost eliminate the ion source memory effect. (3) The use of an improved accuracy tandem accelerator high voltage control for analysing very low final ion fluxes. Finally, (4) there was the need to assess the possible low level radiocarbon and other backgrounds of the accelerators or devices used to assist the isobar separation, after the accelerators had been used previously for many years of nuclear reaction studies. These developments were needed in order to add atomic and molecular isobar separation to the mass spectrometry for the further development of accelerator mass spectrometry (AMS) with tandem accelerators. When the basic problems had been solved, the detection and the accurate measurement of important natural very rare long-lived radio-active isotopes, such as for the sub parts per trillion (14C/C < 10−12) of natural 14C, was facilitated after further research. It was shown that there are very low levels of the atomic isobar anion 14N− from the caesium solid sample sputter ion source and that the 14C could be detected in the presence of over 1010 times as many mass 14 molecular anion hydrides 13CH−. The first and second excited states of the N anion, N(1S)− & N(1D)–, were shown later to exist but with short enough lifetimes for them not to interfere with the detection of 14C− at well below the level of 10−15 of 12C. The residual 14C background for an MP tandem accelerator, previously used for nuclear reaction studies, as well as the ion source memory effect were also found to be smaller than about 14C/C ~ 10−15 after the accelerator voltage control problem had been solved. These aims were all achieved during a week in May 1977 at the University of Rochester, leading also to the promise of the further successful development of radiocarbon dating by ion counting and the natural abundance measurements of other rare long lived radioactive isotopes by mass spectroscopy with anions or cations. In addition, the ability to date much smaller quantities of carbon, by a factor near 1000, was a huge advantage of the new method, as expected. However, it took almost a further decade of research and development to equal the accuracy of the mature beta counting radiocarbon dating method. The elimination of molecular ions from the mass spectrometry was later shown to be the key to detecting very low levels of actinides where atomic isobars are usually absent. The development of AMS for many other long lived radioactive isotopes is still continuing, as is the gradually increasing understanding of the need for an accelerator in some but not in all cases.

Accurate electron affinity of atomic cerium and excited states of its anion**Project supported by the National Natural Science Foundation of China (Grant Nos. 91736102 and 11974199) and the National Key R&D Program of China (Grant No. 2018YFA0306504).

Electron affinities (EA) of most lanthanide elements still remain unknown owing to their relatively lower EA values and the fairly complicated electronic structures. In the present work, we report the high-resolution photoelectron spectra of atomic cerium anion Ce− using the slow electron velocity-map imaging method in combination with a cold ion trap. The electron affinity of Ce is determined to be 4840.62(21) cm−1 or 0.600160(26) eV. Moreover, several excited states of Ce− (4H9/2, 4I9/2, 2H9/2, 2G9/2, 2G7/2, 4H13/2, 2F5/2, and 4I13/2) are observed.

Improvements in the orbitalwise scaling down of Perdew-Zunger self-interaction correction in many-electron regions.

The Perdew-Zunger (PZ) method provides a way to remove the self-interaction (SI) error from density functional approximations on an orbital by orbital basis. The PZ method provides significant improvements for the properties such as barrier heights or dissociation energies but results in over-correcting the properties well described by SI-uncorrected semi-local functional. One cure to rectify the over-correcting tendency is to scale down the magnitude of SI-correction of each orbital in the many-electron region. We have implemented the orbitalwise scaled down SI-correction (OSIC) scheme of Vydrov et al. [J. Chem. Phys. 124, 094108 (2006)] using the Fermi-Löwdin SI-correction method. After validating the OSIC implementation with previously reported OSIC-LSDA results, we examine its performance with the most successful non-empirical SCAN meta-GGA functional. Using different forms of scaling factors to identify one-electron regions, we assess the performance of OSIC-SCAN for a wide range of properties: total energies, ionization potentials and electron affinities for atoms, atomization energies, dissociation and reaction energies, and reaction barrier heights of molecules. Our results show that OSIC-SCAN provides superior results than the previously reported OSIC-LSDA, -PBE, and -TPSS results. Furthermore, we propose selective scaling of OSIC (SOSIC) to remove its major shortcoming that destroys the -1/r asymptotic behavior of the potentials. The SOSIC method gives the highest occupied orbital eigenvalues practically identical to those in PZSIC and unlike OSIC provides bound atomic anions even with larger powers of scaling factors. SOSIC compared to PZSIC or OSIC provides a more balanced description of total energies and barrier heights.

Synthesis, crystal structure, phosphate hydrolysis activity and antibacterial activity of macrocyclic dinuclear Zn(II) complex with benzyl pendant-arms

A new macrocyclic dinuclear Zn(II) complex is synthesized by the cyclocondensation between 3,3’-(ethane-1,2-diylbis (benzylazanediyl))bis(methylene) bis (2-hydroxy-5-methyl-benzaldehyde) and 1,3-diaminopropane and the subsequent with zinc salts. The as-prepared complex is characterized by elemental analysis, FT-IR, ES-MS and single crystal X-ray diffraction. The complex consists of one independent molecular unit of [Zn2(μ-OAC)L]+ ClO4− and two water molecules with one on a symmetry element. Four of these units collectively form two pairs of dinuclear complex units of [Zn2(μ-OAc)L]+ with one unit sharing two perchlorate ions and one water molecule and the other unit sharing two perchlorate ions and one symmetry equivalent water molecule. Each zinc(II) ion exhibits a slightly distorted square pyramidal geometry. Two Zn atoms are bridged by two oxygen atoms of an acetate anion and two phenolic O atoms. The Zn–Zn distance is 2.951 Å. An ordered two-dimensional network is formed by weak intermolecular interactions in the crystal structure of the complex. The phosphate ester hydrolysis activity and the antibacterial activity of the complex are studied. The results showed that the synthesized complex has an efficient catalytic activity of phosphoester bond cleavage and the potential to inhibit the growth of E. coli. The optimum catalytic rate constant (kcat) at pH 7.8 for the hydrolysis of 4-nitrophenyl phosphate disodium salt hexahydrate (pNPP) by the synthesized complex is 2.98 × 10−4 s−1, and 105 times faster than that the spontaneous hydrolysis of the phosphate monoester.

Experimental and DFT studies on surface properties of sulfonate-based surface active ionic liquids

Two anionic surface active ionic liquids (SAILs), 3-methyl-1-ethoxycarbonylimidazolium decanesulfonate ([Etmim][C10H21SO3]) and 3-methyl-1-ethoxycarbonylimidazolium dodecanesulfonate ([Etmim][C12H25SO3]) were synthesized and studied. The surface properties, aggregation properties and thermodynamic parameters of [Etmim][C10H21SO3] and [Etmim][C12H25SO3] aqueous solutions were determined using surface tension and electrical conductivity. Micelle formation of [Etmim][C10H21SO3] and [Etmim][C12H25SO3] was spontaneous and entropy-driven.Density functional theory (DFT) calculation was used to optimize the configuration of the anions (C10H21SO3, and C12H25SO3), imidazolium cation ([Etmim]+), and SAILs ([Etmim][C10H21SO3] or [Etmim][C12H25SO3]) with different number of water molecules (1–3) using Gaussian 16 at B3LYP/6-31G(d,p) level.Typical hydrogen bonds, bond length changes, bond angle changes, and charge changes of typical atoms in hydrated complexes were analyzed. For imidazolium cation hydrates, H2O formed two types of hydrogen bonds with cation ([Etmim]+). For sulfonate anion hydrates, H2O formed two types of hydrogen bonds with anions ([C10H21SO3]- or [C12H25SO3]-). Hydrogen atoms in H2O formed hydrogen bonds with oxygen atoms of polar sulfonate anions in three ways: 1:1, 2:1, and 2:1. The typical electron withdrawing atoms (N and O) in imidazolium cation was beneficial for the micelles formation. The electrostatic repulsion and electrostatic attractive interaction between polar groups of SAILs affected the CMC values of [Etmim][C10H21SO3] or [Etmim][C12H25SO3] aqueous solutions. Binding energy (D0), difference of binding energy (ΔD0) of sulfonate ion hydrates and SAIL hydrates confirmed the tendency of [Etmim][C12H25SO3] micelle formation was higher than that of [Etmim][C10H21SO3].

SYNTHESIS AND STRUCTURE OF (METHOXYMETHYL)TRIPHENYLPHOSPHONIIUM TRICHLORO(DIMETHYLSULFOXIDO)PLATINATE

(Methoxymethyl)triphenylphosphonium trichloro(dimethylsulfoxido)platinate [Ph3PCH2OCH3][PtCl3(dmso-S)] was synthesized by the reaction of hexachloroplatinic acid with (methoxymethyl)triphenylphosphonium chloride in dimethyl sulfoxide. During the reaction, Pt (IV) was reduced to Pt (II). The reactions are accompanied by the ligand exchange in anions with substitution of the S-coordinated dimethyl sulfoxide molecule for one of chlorine atoms. Slow evaporation of the solvent led to the formation of large orange crystals. The product structure was determined by XRDA. The structures were interpreted by the direct method. Positions and temperature parameters of non-hydrogen atoms were refined in isotropic and then in anisotropic approximations by the full-matrix LSM. The X-ray diffraction pattern of crystal I was carried out on a Bruker D8 QUEST diffractometer. According to the data of X-ray analysis the unit cell crystallographic parameters of compound I are [crystal system monoclinic, space group P21/c, M 686.90, a 14.48(2), b 14.48(2), c 19.99(3) Å]. The tetrahedral configuration of the (methoxymethyl)triphenylphosphonium cation approaches the ideal values (CPC angles are 108.5(2)°-110.3(2)°, bond lengths Р-С are slightly differ from each other). Platinum atoms in anions have square coordination (trans-arranged angles ClPtCl are 177.65(5)°, SPtCl are 178.88(6)°, cis-angles approach 90°). The bond lengths Pt–Cl are equal to 2.290(3)–2.314(3) Å, Pt–S are equal to 2.205(3) Å. The platinum atoms are coordinated by three chlorine atoms and dimethyl sulfoxide molecule in the anion. Dimethyl sulfoxide molecule is coordinated to the platinum atoms by sulfur atoms. The geometry of the coordinated dimethyl sulfoxide ligand [OSC and СSC angles, S−O bond] differs from the geometry of a free dimethyl sulfoxide molecule.

The crystal structure, morphology and mechanical properties of diaquabis(omeprazolate)magnesium dihydrate

The crystal structure of diaquabis(omeprazolate)magnesium dihydrate (DABOMD) in the solid state has been determined using single-crystal X-ray diffraction. Single crystals of DABOMD were obtained by slow crystallization in ethanol with water used as an antisolvent. The crystal structure shows a dihydrated salt comprising a magnesium cation coordinating two omeprazolate anions and two water molecules (W1) that are strongly bound to magnesium. In addition, two further water molecules (W2) are more weakly hydrogen-bonded to the pyridine nitrogen atom of each omeprazolate anion. The crystal structure was utilized to estimate key material properties for DABOMD, including crystal habit and mechanical properties, which are required for improved understanding and prediction of the behaviour of particles during pharmaceutical processing such as milling. The results from the material properties calculations indicate that DABOMD exhibits a hexagonal morphology and consists of a flat slip plane through the (100) face. It can be classed as a soft material based on elastic constant calculation and exhibits a two-dimensional hydrogen-bonding framework. Based on the crystal structure, habit and mechanical properties, it is anticipated that DABOMD will experience large disorder accompanied by plastic deformation during milling.

Topological Analysis of Ag-Ag and Ag-N Interactions in Silver Amidinate Precursor Complexes of Silver Nanoparticles.

A series of silver amidinate complexes has been studied both experimentally and theoretically, in order to investigate the role of the precursor complex in the control of the synthesis of silver nanoparticles via an organometallic route. The replacement of the methyl substituent of the central carbon atom of the amidinate anion by a n-butyl group allows for the crystallization of the tetranuclear silver amidinate complex 3 instead of a mixture of di- and trinuclear silver amidinate complexes 1 and 2, as obtained with a methyl substituent. The relative stabilities and dissociation schemes of various isomeric arrangements of silver atoms in 3 are investigated at the computational DFT level of calculation, depending on the substituents of the amidinate ligand. The tetranuclear silver amidinate complex 4, exhibiting a diamondlike arrangement of the four silver atoms, is also considered. Ag-N bonds and argentophilic Ag-Ag interactions are finely characterized using ELF and QTAIM topological analyses and compared over the series of the related di-, tri-, and tetranuclear silver amidinate complexes 1-4. In contrast to the Ag-N dative bonds very similar over the series, argentophilic Ag-Ag interactions of various strengths and covalence degree are characterized for complexes 1-4. This gives insight into the role of the amidinate substituents on the nuclearity and intramolecular chemical bonding of the silver amidinate precursors, required for the synthesis of dedicated AgNPs with chemically well defined surfaces.

Crystal structure of 1,4,8,11-tetra-methyl-1,4,8,11-tetra-azonia-cyclo-tetra-decane bis-[chlorido-chromate(VI)] dichloride from synchrotron X-ray data.

The crystal structure of title compound, (C14H36N4)[CrO3Cl]2Cl2, has been determined by synchrotron radiation X-ray crystallography at 220 K. The macrocyclic cation lies across a crystallographic inversion center and hence the asymmetric unit contains one half of the organic cation, one chloro-chromate anion and one chloride anion. Both the Cl- anion and chloro-chromate Cl atom are involved in hydrogen bonding. In the crystal, hydrogen bonds involving the 1,4,8,11-tetra-methyl-1,4,8,11-tetra-azonia-cyclo-tetra-decane (TMC) N-H groups and C-H groups as donor groups and three O atoms of the chloro-chromate and the chloride anion as acceptor groups link the components, giving rise to a three-dimensional network.

Formation of Bloch Flat Bands in Polar Twisted Bilayers without Magic Angles.

The existence of Bloch flat bands of electrons provides a facile pathway to obtain exotic quantum phases owing to strong correlation. Despite the established magic angle mechanism for twisted bilayer graphene, understanding of the emergence of flat bands in twisted bilayers of two-dimensional polar crystals remains elusive. Here, we show that due to the polarity between constituent elements in the monolayer, the formation of complete flat bands in twisted bilayers is triggered as long as the twist angle is less than a certain critical value. Using the twisted bilayer of hexagonal boron nitride (hBN) as an example, our simulations using the density-functional tight-binding method reveal that the flat band originates from the stacking-induced decoupling of the highest occupied (lowest unoccupied) states, which predominantly reside in the regions of the moiré superlattice where the anion (cation) atoms in both layers are overlaid. Our findings have important implications for the future search for and study of flat bands in polar materials.

Atomic Doping and Anion Reconstructed CoF2 Electrocatalyst for Oxygen Evolution Reaction

AbstractElectrocatalytic water splitting is one of the most promising green solutions for large‐scale hydrogen production, which has developed rapidly in recent years. The slow reaction rate of oxygen evolution reaction (OER) has become the bottleneck to improve the electrocatalytic efficiency. Herein, Fe‐doped CoF2 nanowire arrays on 3D nickel foam are prepared by two steps of hydrothermal reaction and fluorination process. The increased catalytic activity sites and accelerated charge transfer rate make the self‐supported Fe‐doped CoF2 electrode show excellent OER performance in alkaline electrolyte. An overpotential of 230 mV is only required to release a current density of 10 mA cm−2. The Tafel slope derived from the polarization curves is 59 mV dec−1, indicating outstanding electrochemical kinetics performance. A stable output current density of 84 mA cm−2 for more than 96 h is achieved under an invariant overpotential of 338 mV, attributing to the anion reconstruction making part of CoF2 transform into cobalt hydroxide and further improving its electrocatalytic performance.

How Molecular Chiralities of Bis(mandelato)borate Anions Affect Their Binding Structures With Alkali Metal Ions and Microstructural Properties in Tetraalkylphosphonium Ionic Liquids.

Spiroborate anion-based inorganic electrolytes and ionic liquids (ILs) have fascinating electrochemical and tribological properties and have received widespread attention in industrial applications. The molecular chiralities of spiroborate anions have a significant effect on the microstructures and macroscopic functionalities of these ionic materials in application and thus deserve fundamental consideration. In the current work, we performed quantum chemistry calculations to address the binding strength and coordination structures of chiral bis(mandelato)borate ([BMB]) anions with representative alkali metal ions, as well as the electronic properties of alkali metal ion-[BMB] ion pair complexes. The optimized [BMB] conformers are categorized into V-shaped, bent, and twisted structures with varied electrostatic potential contours and conformational energies and distinct alkali metal ion-[BMB] binding structures. Alkali metal ions have additional associations with phenyl groups in V-shaped [BMB] conformers owing to preferential cation-π interactions. Furthermore, the effects of the molecular chiralities of [BMB] anions on the thermodynamics and microstructural properties of tetraalkylphosphonium [BMB] ILs were studied by performing extensive atomistic interactions. Oxygen atoms in [BMB] anions have competitive hydrogen bonding interactions with hydrogen atoms in cations depending on the molecular chiralities and steric hindrance effects of [BMB] anions. However, the molecular chiralities of [BMB] anions have a negligible effect on the liquid densities of tetraalkylphosphonium [BMB] ILs and the spatial distributions of boron atoms in anions around phosphorous atoms in cations. Enlarging tetraalkylphosphonium cation sizes leads to enhanced cation-anion intermolecular hydrogen bonding and Coulombic interactions due to enhanced segregation of polar groups in apolar networks in heterogeneous IL matrices, as verified by scattering structural functions.

Crystal structure of {4-[10,15,20-tris-(4-meth-oxy-phen-yl)porphyrin-5-yl]benzyl 2-diazo-acetato}-zinc(II).

In the title compound, [Zn(C50H36N6O5)], the ZnII cation is chelated by four pyrrole N atoms of the porphyrinate anion and coordinated by a symmetry-generated keto O atom of the diazo-ester group in a distorted square-pyramidal geometry. The mean Zn-N(pyrrole) bond length is 2.058 Å and the Zn-O(diazo-ester) bond length is 2.179 (4) Å. The zinc cation is displaced by 0.2202 (13) Å from the N4C20 mean plane of the porphyrinate anion toward the O atom; the involvement of this atom leads to a [100] polymeric chain in the crystal.

Influence of Halogen Substituent on the Self-Assembly and Crystal Packing of Multicomponent Crystals Formed from Ethacridine and Meta-Halobenzoic Acids

In order to determine the influence of halogen substituent on the self-assembly of the 6,9-diamino-2-ethoxyacridinium cations and 3-halobenzoate anions in the crystals formed from ethacridine and halobenzoic acids, the series of ethacridinium meta-halobenzoates dihydrates: ethacridinium 3-chlorobenzoate dihydrate (1), ethacridinium 3-bromobenzoate dihydrate (2), and ethacridinium 3-iodobenzoate dihydrate (3), were synthesized and structurally characterized. Single-crystal X-ray diffraction measurements showed that the title compounds crystallized in the monoclinic P21/c space group and are isostructural. In the crystals of title compounds, the ions and water molecules interact via N–H⋯O, O–H⋯O and C–H⋯O hydrogen bonds and π–π stacking interactions to produce blocks. The relationship between the distance X⋯O between the halogen atom (X=Cl, Br, I) of meta-halobenzoate anion and the O-atom from the ethoxy group of cation from neighbouring blocks and crystal packing is observed in the crystals of the title compounds.

An interesting theoretical insight into CO2 capture of phosphonium-based ionic liquids with aprotic heterocyclic anions

In this investigation, a systematic understanding of the nature of molecular interactions between aprotic heterocyclic anions (AHAs) and typically phosphonium-based cation named as [Pnnnm]+ (n = 6, and m = 14), has been carried out using density functional theory (DFT) method and Gaussian 09 program at B3LYP/6-311G** basis sets. Multiple stable conformers were determined between the heterocyclic N atoms of the AHA anions that geometrically positioned around the [P66614]+ (C-H(α) bond) so as to formation of maximum non-covalent interactions. According to the Mulliken charge distributions on atoms in gas phase, the computational results show that the [P66614]+[3-Triaz]− ion pair possess of −394.6 kJ mol−1 as highest negative interaction energy, with six hydrogen bonds between N and H atoms of [3-Triaz]− and [P66614]+, respectively. According to the solvent effect results, the charge distributions and interaction energy is more affected by solvent than geometrical conformations. Also, for addition of CO2 molecules to multiple [P66614]+[AHA]−, our investigations indicated that, chemical interacts of one CO2 to the isolated AHA anions clearly resulted in the formation of a covalently bound carbamate with the high strength of binding, while the addition of two or more CO2 molecules leads to non-covalent bond due to the steric effect. Our results reveals the [Inda]− position rather than cation is so that five fairly strong interactions create between ion pairs in “[P66614]+[Inda]- –CO2” conformer and leads to the formation most stable conformer with highest negative interaction energy. Moreover, to the best of our knowledge, this is the first theoretical report to deeply explore the molecular interactions in the [P66614]+[AHA]− ion pairs, as well as interaction strength with the CO2 molecules.

Bis- and mixed-ligand copper(II) complexes of nalidixic acid the antibacterial drug: Mode of nalidixate coordination determines DNA binding and cleavage and cytotoxicity

The new complexes [Cu(nal)2]∙2H2O 1 and [Cu(en)2(nal)2] 2, where H(nal) is the antibacterial drug nalidixic acid, have been isolated and their X-ray structures successfully determined. The complex 1 possesses a square planar CuO4 chromophore constituted by the pyridone and carboxylate oxygen atoms of nalidixate anion. Complex 2 contains a CuN4O2 chromophore with a tetragonally distorted octahedral geometry, and the trans-axial coordination of two nalidixate anions at longer distances to the CuN4 plane constituted by ethylenediamine is stabilized by a network of H-bonding. DFT studies illustrate the structures and stabilities of complexes. The DNA binding affinity of 2 (Kb, 9.2 (±0.2) × 104 M−1) is higher than that of [Cu(en)2]2+ [Kb, 2.0 (±0.2) × 104 M−1], illustrating that bound nal¯ enhances the DNA binding affinity. DNA docking studies reveal that 2 bound to DNA undergoes interesting coordinative distortions more than 1, causing more significant changes in DNA host. Thus, 2 displays oxidative DNA cleavage (ascorbic acid) more prominent than [Cu(en)2]2+, by generating OH radicals, and shows poor cytotoxicity towards A549 lung cancer cell lines.

Crystal structure and antibacterial properties of a new dinuclear copper complex based on an unsymmetrical NN′O type Schiff base ligand

A new dinuclear copper(II) Schiff base complex, [Cu2L2(H2O)2(µ-ClO4)]ClO4, was synthesized and characterized by single crystal X-ray crystallography, FT-IR and UV-Vis spectroscopy, and elemental analysis. In this complex, L−1 is the deprotonated form of N-5-bromosalicylidene-1,3-propanediamine. Single crystals of the complex were crystallized in the monoclinic crystal system and P21/n space group. The geometry around each metal center is distorted octahedral in which the monoanionic Schiff base ligand has occupied three apices of the octahedron and the other three apices are occupied by a water molecule, an oxygen atom of the µ-perchlorato anion, and a phenoxo type oxygen atom from the other Schiff base ligand. Antibacterial properties of the synthesized complex have been investigated against human pathogenic bacteria, such as Escherichia coli, Klebsiella pneumonia, Salmonella (sp) and Proteus (sp), and Staphylococcus aureus. The complex showed moderate antibacterial activity against both Gram-type bacteria with the highest activity against K. pneumonia and E. coli.

Scattering of Attosecond Electromagnetic Field Pulses by Atomic and Molecular Anions Including the Magnetic Field Component

Scattering of an attosecond electromagnetic field pulse by atomic and molecular anions is considered in the sudden perturbation approximation. In the interaction with anions, the effect of the magnetic field of the incident pulse is considered. The inclusion of the magnetic component of the ultrashort pulse leads to new results in the scattering spectra for atomic and molecular anions. Analytic dependences of the partial spectrum on frequency are obtained. It is shown that during scattering, the second harmonic is generated, which makes it possible to determine the type of anions and the spatial orientation of molecular anions.