Phthalate Complexes Research Articles

Ytterbium Coordination Polymer with Four Different Coordination Numbers: The First Structural Characterization of Lanthanide Phthalate Complex

AbstractThe novel ytterbium coordination polymer is a two‐dimensional framework in which the central metal ions have four different coordination numbers and form four kinds of coordination polyhedra. The four kinds of coordination polyhedra connect into infinite chains by sharing oxygen atoms.

Magnetic study of pentavalent neptunium phthalate hexahydrate (NpO 2) 2(O 2C) 2C 6H 4·6H 2O

Magnetic properties of the polycrystalline neptunium(V) phthalate complex hexahydrate (NpO 2) 2(O 2C) 2C 6H 4·6H 2O were investigated in the temperature range of 2–300 K and in the applied fields between −5.5 and +5.5 T. This compound exhibits a magnetic ordering below 4.5 K. At 2 K, the initial magnetization curve exhibits a two-step saturation process; a kink around ∼0.4 T (∼0.68 μ B/Np) and a further increase to a second plateau with a saturation moment, μ sat =1.23 μ B / Np at 5.5 T. The former makes a small hysteresis loop (−0.4 T≤H≤+0.4 T) with a coercive field H C∼0.076 T. Such behavior most likely indicates the existence of the two kinds of Np sublattices, one is ferromagnetic and the other is antiferromagnetic (metamagnetic).

Complexes of beryllium(II) with substituted malonates. Crystal structure of K2[Be(C4H6(COO)2)2]·2H2O

The complexes formed by beryllium(II) with the dicarboxylate ligands methylmalonate, phenylmalonate, dimethylmalonate and cyclobutane-1,1-dicarboxylate have been investigated in aqueous solution through potentiometric and 9Be NMR spectroscopic measurements. The species BeL, [BeL2]2−, [Be3(OH)3L3]3− and [Be3(OH)3L]+ have been identified and their formation constants have been determined at 25°C in 0.5 moldm−3 NaClO4. The stability of the complexes is discussed in relation to the bite size of the chelating ligands; the formation constants of the beryllium(II) phthalate complexes have also been determined for this purpose. A crystalline salt of formula K2[Be(C4H6(COO)2)2]·2H2O has been isolated and its structure has been determined by an X-ray structure analysis. The metal atom is tetrahedrally coordinated by four oxygen atoms of the dicarboxylate ligands, the coordination polyhedron being only slightly distorted from tetrahedral.

Synthesis, spectral and magnetic characterisation of copper(II) dinuclear and polynuclear complexes with a macrocyclic 34-membered hexaamine

34-Membered macrocyclic hexaamine containing two independent N3 donor sets forms homodinuclear copper(II) complexes. Displacements of anions within the copper(II) chloride complexes occurred easily upon addition of different anions to the CuCl2 complex. All new complexes were characterised by elemental analysis, IR, UV/VIS spectroscopy, and magnetic susceptibility measurements. Tetranuclear complexes indicate relation χCu−1 vs. T in agreement with the Curie–Weiss law. A behaviour anomalous in relation to the phthalate complexes is shown by the [Cu4L2Cl4(ox)2] complex in which an antiferromagnetic coupling (J = - 53.9 cm−1) between the Cu2+ ions through the C2O42− bridge is observed.

Synthesis, Infrared Spectra and Crystal Structures of Zinc Phthalate Complexes

Synthesis, Infrared Spectra and Crystal Structures of Zinc Phthalate Complexes

Synthesis, Infrared Spectra and Crystal Structures of Zinc Phthalate Complexes

Synthesis, Infrared Spectra and Crystal Structures of Zinc Phthalate Complexes

Competitive surface complexation of o-phthalate and phosphate on goethite (α-FeOOH) particles

Complexation of o-phthalate (1,2-benzenedicarboxylate) and competitive complexation of phosphate and phthalate at the goethite-water interface have been studied in 0.1 M Na (NO 3) media at 298.2 K within the range 3.0 < -log [H +] < 8.5. Equilibrium measurements were performed as potentiometric titrations supplemented with spectrophotometric phosphate and phthalate analyses.The binary and ternary chemical subsystems H +-goethite and H +-goethite-H 2PO 4− have been investigated earlier and described according to the constant capacitance model. The adsorption of phthalate showed a strong ionic strength dependence which indicated that phthalate is adsorbed as outer-sphere complexes. The experimental data in the subsystem H +-goethite-phthalate were evaluated on the basis of an extended constant capacitance model with the aid of the computer program FITEQL, version 2.0. One plane for inner sphere complexation and one plane for outer-sphere complexation, each with an associated constant capacitance, were included in the extended constant capacitance model. Surface complexation of phthalate is described by two outer-sphere complexes, ≡FeOH 2+L 2− and ≡FeOH 2+ HL −.In the experiments with simultaneous complexation of phosphate and phthalate, the complexation of phosphate was not influenced by the presence of phthalate. On the other hand, the complexation of phthalate was decreased even at low phosphate concentrations. The equilibrium models determined for the subsystems were used to predict the adsorption of phosphate and phthalate in the quaternary system. It was found that these predictions were in good agreement with experimental titration and phosphate/ phthalate adsorption data.Diffuse reflectance IR-spectra were recorded to obtain structural information of the phthalate complexes. The spectroscopic data did not contradict the outer-sphere model. However, because of the complexity of the phthalate molecule conclusive structural assignment could not be made.

Preparation and thermal reactivity of hydrazinium uranyl carboxylates

Hydrazinium uranyl carboxylates with the formula N 2H 5[UO 2L 3]· nH 2O, where for L = salicylate, n = 4; for L = benzoate and p-hydroxybenzoate, n = 2; for L = hydrazinecar-boxylate, n = 1; for L = acetate, propionate and thioglycolate, n = 0, and dihydrazinium uranyl phthalate (N 2H 5) 2[UO 2( o-C 6H 4(COO) 2) 2] have been prepared in aqueous media. The electronic spectra of the complexes confirm the presence of the uranyl cation in the molecules. The infrared spectra of the complexes show the NN stretching frequency of N 2H 5 + in the range of 970–980 cm −1 confirming its ionic nature. The small separation ( Δν < 150 cm −1) between the asymmetric and symmetric stretching vibrations of the carboxylate groups in all the complexes except hydrazinecarboxylate and phthalate compounds, reveals the bidentate chelate coordination of the carboxylate groups. The hydrazinecarboxylate group is coordinated through O and N atoms as a bidentate chelate. IR frequencies also show that one of the carboxylates in the phthalate complex is a monodentate and the other is bidentate chelate. Thus the phthalate ligand bridges in both uni- and bidentate fashion. Simultaneous TG-DTA shows that the aromatic carboxylate complexes, including hydrazinium uranyl hydrazinecarboxylate monohydrate, decompose exothermically whereas the aliphatic counterparts decompose both endo- and exothermically. Except for N 2H 5[UO 2(N 2H 3COO) 3)·H 2O all other complexes decompose via uranyl carboxylate intermediate to give U 3O 8 as the final product. The water molecules are lost endothermically at low temperature (around 100°C) indicating the presence of water molecules as water of crystallisation.

A MOLECULAR MODELLING STUDY OF DICARBOXYLATE ANIONS AND ZINC OXALATE COMPLEX EXTRACTION BY DIPHOSPHONIUM EXTRACTANTS

Abstract A molecular modelling method is used as an aid to predict and to account for the results of solvent extraction of dianions by an ion-exchange extractants such as diphosphonium compounds (polymethylenebis(trioctylphosphonium)s abbreviated as CnBP2+). The extraction ability of CnBP2+ extractants was surprisingly dependent on the dianionic species and on the length of bridging methylene chain connecting the two phosphonium cationic centers which offers an effective molecular recognition field. The dianions studied are phthalate, isophthalate, terephthalate, dibenzoyltartrate and zinc oxalate complex. All of them have their negative charges carried by oxygen atoms. The extracted species considered for a dianion A2− are 1:1 and 2:2 ion-pair species such as (CnBP2+, A2−), (2 CnBP2+, 2 A2−rpar; with n = 2, 4, 6, 8, 10, 12. These ion-pair species are modelled and minimized. The total energy values obtained are processed to calculate the association energies of ion-pair species which allow comparison of 1...

Gold speciation in natural waters: II. The importance of organic complexing—Experiments with some simple model ligands

The solubility of Au has been measured at 25°C in aqueous solutions in the presence of various organic ligands (acetate, benzoate, oxalate, phthalate, salicylate, and thiosalicylate). These ligands were chosen as simple analogs of humic acid moieties in order to model the complexation of Au by humic and fulvic acids in natural waters. With the first five ligands ( ΣL = 0.1 M), solubilities were generally below 25 μg/l, whereas in the thiosalicylate solutions ( ΣL = 0.45 M), a maximum Au concentration of 680 mg/1 was measured. Acetate and benzoate complexes are too weak to detect by the solubility method. Oxalate appears to have a reducing effect on Au in solution, and both oxalate and phthalate complexes of Au(I) may be coordinatively unfavorable. It was only possible to identify one salicylato complex ( log β 2 = 17.5 ± 0.5) and two thiosalicylato species ( log β 1 = 29.9 ± 0.3 and log β 2 = 31.7 ± 0.3). In addition, stability constants for a number of O-, N-, and S-donor complexes of Au(I) were estimated from linear free energy relationships with Cu(I), Ag(I), and Hg(II). General trends in stability constants of Au-organic complexes with various donor atoms are S ⪢ N ≥ O. Calculations based on a simple model of a fulvic acid suggest that Au is almost exclusively bound to S-donor sites under reducing conditions, but AuOH(H 2O) 0 and complexing by organic O-donors are more important in oxidizing environments.

A study of titanium and magnesium chloride complexes with dialkyl phthalates by solid state 13C CP MAS NMR spectroscopy

A series of dialkyl phthalate complexes with magnesium chloride and titanium(IV) chloride has been prepared and characterised by 13C CP MAS NMR spectroscopy. The isotropic chemical shift of the ester carbonyl group did not allow co-ordination to magnesium or titanium to be distinguished in general.

Uranium accumulation in the lichen Cladonia rangiferina. Part II. Toxic effects of cationic, neutral, and anionic forms of the uranyl ion

The toxicity of the uranyl ion to the lichen Cladonia rangiferina (L.) Wigg. was shown to be strongly dependent on chemical speciation. Photosynthetic measurements indicated that the anionic complex of oxalate [Formula: see text] was more toxic than the uncomplexed cation [Formula: see text]. No detrimental response could be assigned to the neutral phthalate complex (UO2L). Toxicity was also affected by the physiological condition of the lichen material. Samples exhibiting low photosynthetic levels typical for winter-collected material were damaged to a greater degree. Neither the cationic nor anionic species induced K+ loss from the lichen and the small release induced by the neutral species of the uranyl ion in phthalate buffer reflects a reduction in membrane integrity resulting from Ca2+ depletion. The effects of the uranyl ion and of the buffers used on Ca2+ displacement from lichen samples are discussed. Uranium uptake induced a reduction in total 14C fixation rates, a decrease in the proportion of radioactivity in the ethanol-soluble fraction, and an increase in the ethanol-insoluble fraction. These effects are ascribed to interference with bicarbonate transfer into the algal cell and the blocking of carbohydrate transport from the algal partner.

Stability constants of phthalate complexes of copper (II), nickel (II), zinc (II), cobalt (II), uranyl (II) and throium (IV) by paper electrophoresis

Stoichiometric stability constants of Cu(II), Ni(II), Zn(II), Co(II), UO2(II) and Th(VI) phthalate have been determined by paper electrophoresis. Phthalic acid (0.005 mol dm−3) was added to the background electrolyte: 0.1 mol dm−3 HClO4. The proportions of C6H5C2O4− and C6H4C2O4= were varied by changing the pH of the electrolyte. These anions yielded the complexes, Cu C6H5C2O4+, Cu C6H4C2O4, Zn C6H5C2O4+, Co C6H5C2O4+, Ni C6H5C2O4+, UO2 C6H5C2O4+, UO2 (C6H4C2O4)2= and Th (C6H4C2O4)2 whose stability constants are found to be 103.0, 104.7, 102.6, 102.5, 102.3, 103.5, 1012.6 and 1013.4 respectively (μ=0.1, temp 40°C).

Thermodynamics of ionic interactions in aqueous solutions—V barium and strontium phthalate complexes

Thermodynamic stability constants of the 1 : 1 complexes of Ba 2+ and Sr 2+ with phthalate ion at five different temperatures determined by the potentiometric method are reported and Δ G, Δ H and Δ S for complex formation are calculated. The effect of hydration characteristics on thermodynamics of ion association is discussed.

Kinetic Studies of the Nickel Phthalate Complex Formation in Solution by the Pressure-jump Method

Abstract The rate constants of the complex formation and the dissociation of the nickel phthalate (o-phthalate) complex have been determined by the pressure-jump method. The thermodynamic parameters of the reaction were obtained from studies at various temperatures between 10 and 30°C. Upon a comparison of the data on the nickel complexes of the succinate, adipate, maleate, and phthalate, no systematic relationship between the nature of the ligands and the kinetic values has been found; this can be ascribed to the monodentated form of these complexes. The rate-determining step is the loss of the water molecule from the inner-coordination sphere of the nickel ion when the monodentated complex is formed.

Humic substances: fulvic acid-dialkyl phthalate complexes and their role in pollution.

Fulvic acid is a water-soluble humic material with relatively low molecular weight that occurs widely in soils and waters. It can combine with lyophobic organic compounds such as alkanes, fatty acids, and dialkyl phthalates to form stable "complexes" that are soluble in water. Fulvic acid in an aquatic environment may act as a vehicle for the mobilization, transport, and immobilization of organic compounds, some of which may be toxic pollutants.

Synthesis of Copper(II) Complexes with Maleic Acid

Abstract Three copper(II) complexes with maleic acid, [Cu mal(H2O]) (I) (mal=C2H2(COO)2), [Cu(Hmal)2(H2O)4] (II) and [Cu2(Hmal)4]·H2mal·4EtOH (III) (EtOH=C2H5OH), were synthesized. Compound I was prepared from an aqueous solution of copper(II) sulfate pentahydrate and sodium hydrogenmaleate at room temperature as fine blue crystals. Compound II was prepared by adding little by little copper(II) hydroxide or copper(II) hydroxycarbonate to an aqueous solution of maleic acid at a temperature below 0°C in an ice-salt bath, obtaining light-blue powdered crystals. Compound III was prepared by heating a mixed alcoholic solution of maleic acid anhydride, copper(II) sulfate pentahydrate and sodium carbonate anhydride (3:1:1) in a flask with a reflux condenser for two hours. Fine bluish-green crystals were obtained. By using copper(II) hydroxide instead of copper(II) sulfate in the above preparation, a better yield can be obtained. The effective magnetic moments of I and II were 2.00 B. M. (20°C) and 1.97 B. M. (20°C), respectively, which are relatively close to the spin-only value of the divalent copper ion. On the other hand, the magnetic moment of III was subnormal, being 1.12 B. M. (18°C). The reflection spectrum of III gave a shoulder near 370 mμ, which is specific to green copper complexes. The product (IV) obtained by the thermal decomposition of I at 220°C and the product (V) obtained from II at 160°C, which are presumed to have the chemical formula [Cu-mal(H2O)0.1] and [Cu(Hmal)(mal)1⁄2], respectively, gave normal magnetic moments, 1.91 and 1.89 B. M. (20°C). However, product (VI), obtained by expelling the alcohol from III had a magnetic moment of 1.31 B. M. (17°C). Different from the corresponding copper(II) phthalate complexes, no green copper complexes having subnormal magnetic moments could be obtained through dehydration of the blue maleate complex I or the light-blue complex II having normal magnetic moments.

Iron, chromium and aluminium phthalate complexes and their application to the determination of the metals : A heterometric study

Using a new ”heterometric“ method, a series of soluble and insoluble phthalates were obtained and their behaviour, composition and analytical application studied.