Molar Electrical Conductivity Research Articles

Alkali-metal-regulated construction of superhydrophilic ZnII and CdII coordination polymers with perhalogenated terephthalate ligands

By simply introducing different alkali metal ions as structure-directing agents, four new coordination polymers with the formulae [Cd3(BDC-F4)3(DMF)2(MeOH)6]n (1), [Cd(BDC-F4)(DMF)2(H2O)2]n (2), [Zn2Na2(BDC-Cl4)3(DMF)4(μ2-MeOH)]n (3) and [ZnK(BDC-Cl4)1.5(DMF)(Me2NH)]n (4) (BDC-F4 = 2,3,5,6-tetrafluoro-benzenedicarboxylate; BDC-Cl4 = 2,3,5,6-tetrachloro-benzenedicarboxylate; DMF = dimethylformamide and Me2NH = dimethylamine) have been synthesized and structurally characterized. Complex 1 presents an open three-dimensional (3D) 3-nodal (3,4)-connected framework, 2 has a one-dimensional (1D) chain structure, 3 features a 3D 4-nodal (3,4,5,6)-connected coordination network constructed from the new ZnII–NaI heterometallic tetranuclear cluster, and 4 shows a 3D 4-nodal (3,5,6)-connected network based on the unique ZnII–KI heterometallic tetranuclear cluster. The results reveal the significant influence of alkali-metal ions on the structural topologies of complexes 1–4. Interestingly, compounds 1–4 all exhibit high water solubility, and futher evaporation of their water solution will result in a 1D coordination polymer {[Cd4(BDC-F4)4(H2O)11]·3.5H2O}n (5) consisting of the unprecedented polymeric [CdII–H2O]n chain, and a zero-dimensional (0D) complex [Zn(H2O)6]·(BDC-Cl4)·4H2O (6) containing the discrete [Zn(H2O)6]2+ cationic and BDC-Cl4 dianionic moieties. Furthermore, the solution chemistry of complexes 5 and 6 has been investigated by electrospray ionization (ESI) mass spectrometry and molar electrical conductivity. The photoluminescent properties of complexes 1–6 have also been explored, which interestingly indicate a strong blue emission of complex 1 in the solid state at room temperature.

SYNTHESIS AND STUDY SOME MIXED LIGANDS COMPLEXES FROM FOLIC ACID WITH 1,10-PHENANTHROLINE AND 8-HYDROXYQUINOLINE.

Mixed ligands complexes of the general formula [M(FO)(Phen)(H2O)2].XH2O and K[M(FO)(HQ)(H2O)2].H2O where:[M(II)=Fe(II),Co(II),Ni(II) and Cu(II). FO=Folic acid ,Phen=1,10-Phenanthroline and HQ=8-hydroxyquinoline .Were prepared complexes were characterized using infrared (FT-IR) , ultraviolet spectroscopy (UV-Vis) ,elements of analysis (C.H.N.) , atomic absorption , magnetic sensitivity and the molar electric conductivity measured .The results showed that the prepared complexes have the general formula [M(II ): FO: (Phen or HQ)] and had octahedral structure

Electrical Conductivity Studies of Tetraalkylammonium Bromides in Aqueous Solutions at Several Temperatures

The molar electrical conductivities of tetramethylammonium, tetraethylamonium, tetra-n-propylammonium, and tetra-n-butylammomium bromides in aqueous solutions at (278.15, 283.15, 288.15, 293.15, and 298.15) K have been measured in the concentration range from (0.002 to 0.04) mol·kg–1. The data were analyzed according to the low-concentration chemical model (lcCM) of Barthel. Values of the limiting molar conductivities, Λ∞, and association constants, KA, were evaluated. Using known values for the limiting molar conductivity of bromide ion, the limiting molar conductivities of the tetraalkylammonium cations were evaluated at all temperatures. The Walden product and the Eyring activation enthalpy were calculated. The results are discussed in terms of solute–solvent interactions.

Oximato bridged dinuclear copper(II) complexes: Synthesis, crystal structure, magnetic, thermal, electrochemical aspects and BVS analysis

Reactions of the Schiff-base ligand, 2-hydroxyimino-3-(2-hydrazonopyridyl)-butane (LH) with copper(II) perchlorate hexahydrate and copper(II) nitrate trihydrate in 1:1molar proportion in methanol give rise respectively to Cu2L2(ClO4)2 (1a) and Cu2L2(NO3)2 (1b) in substantial yields. The complexes have been characterized by C, H and N microanalyses, copper estimation, ESI-MS, FT-IR, UV–Vis spectra, molar electric conductivity and room temperature magnetic susceptibility measurements. The X-ray crystal structures of both 1a and 1b have been determined. The structures reveal that both the complexes are oximato bridged dinuclear Cu(II) assemblies. The electrochemical studies of 1a and 1b show Cu(II) to Cu(III) oxidation in methanol. The thermal behavior of the nitrate analog, 1b, has also been forwarded to delve into the structure. Bond-Valence Sum (BVS) method of analyses was also performed to assign the oxidation state for each copper center both in 1a and 1b.

Synthesis and characterization of some new complexes of Cu(II), Ni(II) and V(IV) with Schiff base derived from indole-3-carboxaldehyde. Biological activity on prokaryotes and eukaryotes

Six new Cu(II), Ni(II), and VO(II) complexes (1–6) with Schiff base 1-phenyl-2,3-dimethyl-4-(1H-indole-3-carboxaldehyde)-3-pyrazolin-5-one (HL) were synthesized. The Schiff base was prepared through the condensation of 1-phenyl-2,3-dimethyl-4-amino-3-pyrazolin-5-one (antipyrine) with 1H-indole-3-carboxaldehyde. The new obtained compounds were characterized by 1H NMR, 13C NMR, UV–VIS, IR, EPR spectroscopy, elemental analysis, molar electric conductibility, magnetic susceptibility and thermal gravimetric analysis. In addition, the structure of the ligand HL has been determined by X-ray diffraction methods. The biological activity of complex compounds was investigated in terms of antibacterial effect on prokaryotic cells, by using paper disc diffusion technique, and for antiproliferative effect on eukaryotic cells, by monitoring mitotic activity in timelapse videomicroscopy experiments. The compounds were screened for their antibacterial activity against gram-positive bacteria (Staphylococcus aureus var. Oxford 6538, Klebsielle pneumoniae ATCC 100131 and Legionella monocytogenes ATCC 35182), gram-negative bacteria (Escherichia coli ATCC 10536, Pseudomonas aeruginosa ATCC 9027 and Salmonella typhimurium ATCC 14028) and anti-fungal activity (Candida albicans and Aspergillus flavus) using paper disc diffusion technique. The minimum inhibitory concentrations (MICs) of the compounds were also determined by agar streak dilution method. Compounds 3 and 4 proved to be the most effective as antibacterial agents. The antiproliferative activity was investigated by counting the number of mitoses for HeLa, and MCF7 cells. No significant antiproliferative effect was noted for HL and complex 2, for both used cell types. For complexes 1 and 3 complete inhibition of cell proliferation was observed in the case of HeLa cells, while the effects on MCF7 cell proliferation were lower.In conclusion, six new complex compounds were synthesized, and their biological activity investigated on both prokaryotic and eukaryotic cells, proving that some of them could be putative therapeutic substances.

Trans-Dichloro(η 2-ethylene) (N-3-pyridinylmethanesulfonamide)platinum(II). Crystal structure, spectroscopic, and thermoanalytical characterization, and cytotoxicity assays

The organometallic complex, trans-[PtCl2(η 2-C2H4)(PMSA)] (1), where PMSA = N-3-pyridinylmethanesulfonamide, has been synthesized and characterized by elemental analysis, molar electric conductivity, IR, electronic, and NMR (1H, 13C, and 195Pt) spectroscopy, and thermal analysis. X-ray crystallography revealed that in 1 [monoclinic, P21 c, a = 5.1260(1), b = 19.1600(4), c = 12.7990(3) Å, β = 97.242(2)°, Z = 4] Pt(II) shows planar coordination geometry with PMSA coordinated via the pyridine. The ethylene is virtually perpendicular to the PtCl2N plane with the pyridine ring twisted relative to this plane by 47°. In in vitro assays, PMSA, K[PtCl3(η 2-C2H4)] · H2O, and 1 do not exhibit appreciable cytotoxic activity against human K562 and HepG2 tumor cell lines.

DOMAINS OF SOLVATED IONS IN AQUEOUS SOLUTIONS, THEIR CHARACTERISTICS AND IMPACT ON ELECTRIC CONDUCTIVITY: THEORY AND EXPERIMENTAL EVIDENCE

In this paper, we identify a yet unreported, quantum-electro-dynamic (QED) interactions induced, self-organization in aqueous solutions. We show that its characteristics conform to hitherto unexplained experimental findings, reported in the literature. Specifically, our analysis shows: (a) Solvated ions may organize into micrometer (μm) sized domains, wherein the plasma oscillations of identical ions are in-phase. (b) These liquid domains have a crystalline-like lattice structure. (c) For salt solutions, for concentrations C below a solute specific transition concentration C trans , the ions organize into the "in-phase" domains. For C larger than C trans , domains form wherein the plasma oscillations of the solvated ions are just coherent. Previous studies provided theoretical and experimental evidence for the "coherent" domains. However, they did not show that the "coherent" domains only exist for C > C trans . Typically, at room temperature and pressure, C trans is about 10-4 M or below. (d) At C trans , the molar electric conductivity sharply changes, i.e. for C < C trans , the slope of the molar electric conductivity dependence on concentration is several times larger than for C > C trans .

Electrochemical properties of aqueous solutions of fullerenol-d

Dependence of the pH value on the concentration of fullerenol solutions was studied by means of pH-potentiometry, and the apparent degree of dissociation and the dissociation constant of fullerenol were calculated. The dependence of the electrical conductivity of fullerenol solutions on their concentration was examined. The molar electrical conductivity and also the apparent degree of dissociation and the dissociation constant of fullerenol were calculated.

Association of ionic liquids in solution: a combined dielectric and conductivity study of [bmim][Cl] in water and in acetonitrile

Ion association of the ionic liquid [bmim][Cl] in acetonitrile and in water was studied by dielectric spectroscopy for salt concentrations c ≤ 1.3 M at 298.15 K and by measurement of molar electrical conductivities, Λ, of dilute solutions (c ≤ 0.006 M) in the temperature range 273.15 ≲ T/K ≤ 313.15. Whilst acetonitrile solutions of [bmim][Cl] exhibit moderate ion pairing, with an association constant of K°(A) ≈ 60 M(-1) and increasing with temperature, [bmim][Cl] is only weakly associated in water (K°(A) ≈ 6 M(-1)) and ion pairing decreases with rising temperature. Only contact ion pairs were detected in both solvents. Standard-state enthalpy, entropy and heat capacity changes of ion association were derived, as well as the activation enthalpy of charge transport and the limiting conductivity of the cation, λ(∞) ([bmim](+)). These data, in conjunction with effective solvation numbers obtained from the dielectric spectra, suggest that the solvation of [bmim](+) is much weaker in water than in acetonitrile.

Some new Cu(II) complexes containing an ON donor Schiff base: Synthesis, characterization and antibacterial activity

Six new copper(II) complexes, CuLCl·H 2O ( 1), CuL(NO 3)·2H 2O ( 2), [Cu(L) 2] ( 3), CuL(SCN)·2H 2O ( 4), CuL(ClO 4)·2H 2O ( 5) and (CuL) 2(SO 4)·4H 2O ( 6), where HL = 1-phenyl-2,3-dimethyl-4-(N-2-hydroxy-4-methoxy-benzaldehyde)-3-pyrazolin-5-one, have been synthesized. The characterization of the newly formed compounds was done by 1H NMR, UV–Vis, IR, ESR spectroscopy, elemental analysis and molar electric conductivity. The crystal structure of 1-phenyl-2,3-dimethyl-4-(N-2-hydroxy-4-methoxy-benzaldehyde)-3-pyrazolin-5-one has been determined by X-ray diffraction studies, as well as the crystal structure of one of its copper(II) complexes, [Cu(L) 2] ( 3). The copper atom is coordinated to two nitrogen and two oxygen atoms of the Schiff base ligand. The in vitro antibacterial activity against Klebsiella pneumoniae ATCC 100131, Staphylococcus aureus var. Oxford 6538, Pseudomonas aeruginosa ATCC 9027 and Escherichia coli ATCC 10536 strains was studied and compared with that of free ligand. The anti-microbial activity was dependent on the microbial species tested and the metal salt anion used.

Interactions of cobalt chloride with saccharose in aqueous solutions at 298.15 K

Mutual diffusion coefficients (interdiffusion coefficients) and molar electrical conductivities have been measured for cobalt chloride aqueous solutions in the absence and the presence of saccharose at different concentrations (from 0.01 to 0.3 mol dm −3) and 298.15 K. The diffusion coefficients were measured by using the conductimetric method. For these aqueous solutions, limiting molar conductivity values have been calculated. The value of λ 0(Co 2+) = 105.36 × 10 −4 S m 2 mol −1, obtained at 298.15 K in pure water solution, agrees well with that reported in the literature. The Nernst diffusion coefficient values derived from diffusion (1.301 × 10 −9 m 2 s −1) and from conductance (1.295 × 10 −9 m 2 s −1) are also in good agreement. The dependence of diffusion coefficients and electrical conductivity of CoCl 2 on the concentration of saccharose is discussed by considering the effect of the carbohydrate on the electrolyte dehydration, as well as on the ion-pairs and complexes (CoCl 2–saccharose and ions–saccharose) formation.

Synthesis, characterization antibacterial and antiproliferative activity of novel Cu(II) and Pd(II) complexes with 2-hydroxy-8-R-tricyclo[7.3.1.0. 2,7]tridecane-13-one thiosemicarbazone

Synthesis and biological activity investigation of complex compounds of Cu(II) are challenging issues because of the metal is not a xenobiotic one and the activity of ligands could be modulated by complexation. Complex combinations of Cu(II) and Pd(II) with thiosemicarbazone derivatives of 2-hydroxy-8-R-tricyclo[7.3.1.0. 2,7]tridecane-13-one (where R = C 3H 7, C 4H 3O) were synthesized. The characterization of the ligands and the newly formed compounds was done by 1H NMR, 13C NMR, UV–vis, IR, ESR spectroscopy, elemental analysis, molar electric conductibility and thermal studies. Experiments performed to identify the structures proved that the ligands coordinate to metal ions in different ways – neutral bidentate or mononegative bidentate. Also, if copper(II) acetate, copper(II) nitrate, copper(II) chloride and copper(II) thiocyanate were used, the ligands coordinated in a mononegative bidentate fashion. If copper(II) sulfate was used, the ligands coordinated in a neutral bidentate fashion. The biological activity for the copper(II) synthesized compounds was assessed in terms of antibacterial or antiproliferative activity. The antibacterial activity of the complexes against Staphylococcus aureus var. Oxford 6538, Escherichia coli ATCC 10536, Klebsielle pneumoniae ATCC 100131 and Candida albicans ATCC 10231 strains was studied and compared with that of free ligands. The effect of complex compounds on the proliferation of HeLa cells was tested. For all tested complexes an antiproliferative activity was noted at concentrations higher than 1 μM, but lower than 10 μM. Therefore, complex compounds of copper(II) were synthesized, structurally characterized and tested for biological activity, proving both antibacterial and antiproliferative activity.

Metal-based biologically active agents: Synthesis, characterization, antibacterial and antileukemia activity evaluation of Cu(II), V(IV) and Ni(II) complexes with antipyrine-derived compounds

The paper presents the synthesis of complex combinations of Cu(II), V(IV) and Ni(II) with Schiff bases obtained through the condensation of 4-amino-1,5-dimethyl-2-phenyl-1H-3-pyrazol-3(2H)-one (antipyrine) with 2-hydroxybenzaldehyde, 4-hydroxy-5-methoxyisophthalaldehyde and 4,5-dihydroxyisophalaldehyde respectively. The characterization of newly formed complexes was done by 1H NMR, 13C NMR, UV–VIS, IR, EPR spectroscopies and molar electric conductibility studies. The effect of these complexes on proliferation of human leukemia cells (HL-60) and their antibacterial activity against Staphylococcus aureus var. Oxford 6538, Escherichia coli ATCC 10536 and Candida albicans ATCC 10231strains were studied and compared with those of free ligands.

Synthesis, characterization and antibacterial activity of some new complexes of Cu(II), Ni(II), VO(II), Mn(II) with Schiff base derived from 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one

Abstract Coordination compounds of Cu(II), VO(II), Ni(II), and Mn(II) with the Schiff base obtained through the condensation of 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one with 3-formyl-6-methyl-chromone were synthesized. The characterization of the newly formed compounds was done by 1H NMR, UV–Vis, IR, ESR spectroscopy, elemental analysis and molar electric conductibility. The crystal structure of 1-phenyl-2,3-dimethyl-4-(N-3-formyl-6-methyl-chromone)-3-pyrazolin-5-one (HL) has been determined by X-ray diffraction studies, as well as the one of its copper(II) complex [CuL(OAc)]·CH3OH which contains an anionic ligand and an acetate in the coordination sphere of the metal. The single crystal X-ray structure for (HL) was analyzed for its various weak H-bonding and dimeric association. The in vitro antibacterial activity against Staphylococcus aureus var. Oxford 6538, Klebsiella pneumoniae ATCC 100131, Escherichia coli ATCC 10536, and Pseudomonas aeruginosa ATCC 9027 was studied and compared to the activity of the free ligand.

Electrical conductivity of lithium chloride solutions in the system isopropyl alcohol-water

Electrical conductivity of lithium chloride solutions in the system isopropyl alcohol-water in the temperature range 290–323 K was studied. The dependences of the specific and molar electrical conductivity of the solutions on the concentration of water and lithium chloride were determined.

Electrical conductivity and ionic association of lithium and sodium perchlorates in tetrahydrofuran

The total limiting molar electrical conductivities of ions and triads of ions and the association constants of ions with the formation of ion pairs and triads of ions were calculated from the concentration dependences of the electrical conductivity of solutions of lithium and sodium perchlorates in tetrahydrofuran at 278.15–318.15 K with the use of the method specially developed earlier. The experimental total limiting electrical conductivities were used to calculate the limiting molar electrical conductivities and attraction friction factors of separate ions (Li+, Na+, ClO 4 − , Li2ClO 4 + , Na2ClO 4 + , Li(ClO4) 2 − , and Na(ClO4) 2 − ). The constants of ion association into ion pairs were used to calculate the Gibbs energy of non-Coulomb interionic interaction (ΔG*+−), and the constants of association into triads of ions, to determine the a 3 distance parameter between the centers of the ion and the dipole of the ion pair. Positive ΔG*+−), values and deviations of the experimental a 3 value from the distance parameter calculated theoretically (a 3 0 ) for the triad of ions (Δa 3 = a 3 − a 3 0 ) were related to non-Coulomb repulsion in the region of overlap of the solvation shells of ions and the influence of temperature and ion charge density on this repulsion.

The Possible Presence of Triple Ions in Electrolyte Solutions of Low Dielectric Permittivity

The cause of the appearance of a minimum in the molar electrical conductivity in many electrolyte solutions with increasing electrolyte concentration, in solvents of low dielectric permittivity, is reviewed. Tentative explanations include the formation of triple ions or, alternatively, changes in the electrical polarization of the solutions due to the presence of electrolyte ion pairs. Theoretical models for linear triple ions and apolar dimers are examined. Experimental evidence favors the polarization hypothesis over triple ions; the presence of a maximum in the dielectric permittivity with increasing electrolyte concentration is consistent with the presence of an equilibrium between ion pairs, AB, and their dimers, A2B2, at higher concentrations.

The electrical conductivity, density and surface tension of molten salts containing zirconium fluoride

The temperature dependencies of specific electric conductivity, density and surface tension of molten LiF-KF-ZrF4 mixtures in a wide concentration range were investigated using relative capillary method and method of maximum pressure in a gas bubble. The obtained values of molar electric conductivity, molar volumes and excess thermodynamic functions of melt surface layer have noticeable deviations from those calculated for ideal mixtures. This phenomenon can be explained by some specific interaction between the components of studied ternary mixtures. Mixing the components in such melts is accompanied by a noticeable interaction with predominant formation of stable zirconium fluoride complex ions. The values of deviations depend on the ionic composition of the salt mixtures.

Dimethyl Sulfoxide Containing Platinum(II) and Palladium(II) Chelate Complexes of Glyoxylic and Pyruvic Acid Thiosemicarbazones. A New Class of Cytotoxic Metal Complexes

Abstract The complexes [Pt(DMSO)(GT)]·DMSO (1), [Pt(DMSO)(PT)]· 1/2 DMSO (2) and [Pd(DMSO)- (PT)] (3), where DMSO = dimethyl sulfoxide, H2GT = glyoxylic acid thiosemicarbazone and H2PT = pyruvic acid thiosemicarbazone, have been synthesized and characterized by elemental analysis, molar electric conductivity, IR, electronic and NMR (1H and 13C) spectra. The single crystal X-ray diffraction analysis has revealed for 1 (orthorhombic, Pnma, a = 12.941(3), b = 7.108(2), c = 15.148(3) Å , Z = 4) that the doubly deprotonated thiosemicarbazone molecule is coordinated to Pt(II) via the carboxylato O, azomethine N and thiolato S atoms forming two condensed fivemembered chelate rings. The fourth coordination site of Pt(II) is occupied by the S atom of DMSO. All the atoms of the complex molecule are coplanar except the methyl groups. The O atom of DMSO is in cis-position towards the thiolato-S atom (point group Cs). A system of hydrogen bonds of the type N-H· · ·O links the complex molecules between them and with the lattice DMSO molecules. Similar structures have been deduced for the remaining two complexes on the basis of spectroscopic data. The three complexes and the ligand H2GT exhibit cytotoxic activity against F4N leukemia cells, whereas the ligand H2PT is inactive.

Synthesis, Characterization, and Susceptibility of Bacteria of Selenium Dioxide Complexes with Sulfadrugs

Selenium dioxide complexes of sulfanilamide, sulfadiazine, sulfathiazole, sulfamethoxazole, and sulfadimidine have been synthesized and characterized by elemental analyses, molar electrical conductivities, infrared and electronic spectra, 1H NMR, and thermogravimetric analyses. Two types of complexes, 1:1 and 1:2 (mental:ligand) were shown to have formed. Sulfadrugs behave as monodentate ligands, binding the metal ion through the anilino nitrogen. In vitro susceptibility tests of these complexes against Staphylococcus aureus and Bacillus subtilis were performed. The results showed that the antibacterial activity of the complexes of sulfanilamide, sulfadiazine, and sulfathrazole were stronger than that of the corresponding sulfadrugs, while the complexes of sulfamethoxazole and sulfadimidine were less active.