Effect of Anions on the Development of Color Reactions of Cadmium, Lead, and Mercury with Dithizone and 4-(2-Pyridylazo)resorcinol on a Fibrous Material Filled with the Anion Exchanger AV-17

The effect of nitrates, chlorides, iodides, sulfates, thiosulfates, thiocyanates, acetates, tartrates, nitrilotriacetates, and ethylenediaminetetraacetates in the sorption of Cd(II), Pb(II), and Hg(II) and their subsequent determination with dithizone and 4-(2-pyridylazo)resorcinol (PAR) on the solid phase of a fibrous anion-exchange sorbent filled with AV-17 was studied. The dependences of the analytical signals of complexes adsorbed on the solid phase on the concentration of anions in the solution and on the stability of anionic complexes were revealed. The analytical signals in the sorption and determination of Cd, Pb, and Hg with dithizone and PAR on the solid phase were maximum for iodide and thiosulfate complexes. Conditions of the sorption of Cd(II), Pb(II), and Hg(II) were found for their subsequent total and separate determination with PAR and dithizone.     

Determination of Mercury(II) with Dithizone by Diffuse Reflectance Spectrometry on a Fibrous Anion Exchanger

The possibility of the determination of mercury(II) with dithizone on the solid phase of a fibrous ion-exchange material filled with the AV-17 anion exchanger was studied. Mercury is adsorbed as an anionic complex. The sorption of mercury as chloride, iodide, sulfate, thiosulfate, nitrate, and EDTA complexes was studied. A procedure was proposed for the sorption–spectrometric determination of mercury with dithizone on a solid phase after sorption as the chloride complex. For improving the selectivity of the method, EDTA is added to the solution. The determination is affected only by Pd(II). The time of analysis is 15 min. The procedure was tested in the analysis of tap and river water and a solution modeling natural water.     

Complexes of cyclic aminomethylphosphines with Pt(II), Pd(II), Cu(I), and Ag(I) salts

1,3,5-Diazaphosphorinanes and 1,5,3,7-diazadiphosphacyclooctanes form complexes with Pt(II), Pd(II), Cu(I), and Ag(I) salts. Platinum and palladium are coordinated through phosphorous atoms. In the case of 1,3-diphenyl-5-p-toluidenomethyl-1,3,5-diazaphosphorinane complex formation with platinum and palladium is accompanied by formation of a new polydentate ligand, p-tolylbis-(1,3-di-p-tolyl-1,3,5-diazaphosphorinane-5-yl)methylamine, where the metal is also bonded to phosphorus atoms.DeceasedA. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, 420083 Kazan'. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 335–342, February, 1992.     

Test Method for the Determination of Mercury(II) with Dithizone on the Solid Phase of a Fibrous Anion Exchanger

The sorption and determination of mercury(II) on the solid phase of a fibrous polyacrylonitrile material filled with the AV-17 anion exchanger is studied. Mercury is adsorbed in the form of the chloride complex from a solution with pH 5–7.5; it is determined on the solid phase by the reaction with dithizone either visually or by the measuring the color hue. A procedure for the test determination of mercury(II) has been developed and tested in the analysis of fresh natural waters by the added–found method. The detection limit is 0.02 mg/L. The time of analysis of 5 or 6 samples is no more than 15–20 min.     

Optimal Conditions of Ion-Exchange Synthesis of Cobalt(II) Hydroxide with AV-17-8 Anion Exchanger in the OH Form

Ion-exchange synthesis of cobalt(II) hydroxide by treatment of aqueous solutions of cobalt salts with OH form of AV-17-8 anion exchanger was studied. The influence of time, anion of cobalt salt, number of precipitation stages, and anion exchanger swelling on the degree of cobalt(II) precipitation was examined.     

Determination of Lead with 4-(2-Pyridylazo)resorcinol after the Sorption of Lead as its Thiosulfate Complex on a Fibrous Sorbent Filled with AV-17

The sorption of lead from a thiosulfate solution on a fibrous material filled with AV-17 (PANF-AV-17) was studied. Lead was determined by the color reaction with 4-(2-pyridylazo)resorcinol (PAR) on the solid phase by diffuse reflectance spectrometry. Optimal conditions were selected for lead sorption (pH 4.5 ± 0.5) and determination (pH 10); the selectivity of the determination was studied. A new system Pb–thiosulfate–(PANF-AV-17)–PAR was proposed for the determination of lead on the solid phase. A procedure was developed for the determination of lead in fresh water with the detection limit 0.01 mg/L and RSD < 25%.     

Hg(II), Tl(III), Cu(I), and Pd(II) Complexes with 2,2'-Diphenyl-4,4'-Bithiazole (DPBTZ), Syntheses and X-Ray Crystal Structure of [Hg(DPBTZ)(SCN)2]

Reaction of the ligand 2,2′-diphenyl-4,4′-bithiazole (DPBTZ) with Hg(SCN)₂, Tl(NO₃)₃, CuCl, and PdCl₂ gives complexes with stoichiometry [Hg(DPBTZ)(SCN)₂], [Tl(DPBTZ)(NO₃)₃], [Cu(DPBTZ)(H₂O)Cl]_, and [Pd(DPBTZ)Cl₂]. The new complexes were characterized by elemental analyses and infrared spectroscopy. The crystal structure of [Hg(DPBTZ)(SCN)₂] determined by X-ray crystallography. The Hg atom in the title monomeric complex, (2,2′-diphenyl-4,4′-bithiazole)mercury(II)bisthiocyanate, [Hg(C₁₈H₁₂N₂S₂)(SCN)₂], is four-coordinate having an irregular tetrahedral geometry composed of two S atoms of thiocyanate ions [Hg-S 2.4025(15) and 2.4073(15) Å] and two N atoms of 2,2′-diphenyl-4,4′-bithiazole ligand [Hg-N 2.411(4) and 2.459(4) Å]. The bond angle S(3)-Hg(1)-S(4) of 147.46(5)° has the greatest derivation from ideal tetrahedral geometry. Intermolecular interaction between Hg(1) and two S atoms of two neighboring molecules, 3.9318(15) and 3.9640(18) Å, make the Hg(1) distort from a tetrahedron to a disordered octahedron. The attempts for preparation complexes of Tl(I), Pb(II), Bi(III), Cd(II) ions with 2,2′-diphenyl-4,4′-bithiazole ligand were not successful and also the attempts for preparation complexes of 4,4′,5,5′-tetraphenyl-2,2′-bithizole ligand with Cu(II), Ni(II), Co(II), Co(III), Mn(II), Mn(III), Fe(II), Fe(III), Cr(III), Zn(II), Tl(III), Pb(II), Hg(II), Cu(I), Pd(II) were not successful. This point can be regarded as the initial electron withdrawing of phenyl rings and also their spatial steric effects.     

Sorption of Co(II), Ni(II), Ag(I) and Au(III) on pyrazolone-containing inorganic sorbents

The sorption capacity of 3-methyl-1-phenyl-pyrazolone-5 (HMPP)- modified inorganic sorbents has been investigated. The new sorbents are suitable for simultaneous concentration of the 3d elements being investigated over a wide pH range. Choosing appropriate pH values for the corresponding elements, it is possible to achieve their separate extraction.     

Sorption of mercury(II), zinc(II), and iron(III) thiocyanate complexes on AV-17 anion exchanger and KU-2 cation exchanger modified with rhodamine Zh

Sorption of anionic mercury(II), zinc(II), and iron(III) thiocyanate complexes on KU-2 cation exchanger modified with Rhodamine Zh and on AV-17-8 strongly basic anion exchanger were studied in relation to the concentration of SCN^? ions and solution pH. Optimal conditions of sorption of metal complexes from dilute solutions were found.     

Complexes of 3,3′-Oxybis[(diphenylphosphino)methylbenzene] with Ni(II), Pd(II), Pt(II), Rh(I), and Ag(I). How Important is Backbone Rigidity in the Formation of trans-Spanning Bidenatate Chelates??

The bidentate diphosphine ligand, 3,3′-oxybis[(dipenylphosphino)methylbenzene] ( 1 ) forms monomeric, trans-square-planar complexes MX₂( 1 ) (M = Ni, Pd, Pt; X = Cl^?, Br^? I^?, and, in part, N, NCS^?, CN^?, NO) as well as Pt(H)Cl( 1 ), Pt(H)Br( 1 ), and RhCl(CO)( 1 ). Polymeric species have been observed with substitutionally inert metal centres: trans-[PtCl₂( 1 )]₂ and cis-[PtCl₂( 1 )]_n (mean value of n ≈ 4–5) ³¹P-NMR, and selected IR and UV/VIS parameters are reported. Ligand 1 shows a marked preference for trans-spanning and monomeric chelate formation, despite its various degrees of freedom of internal rotation in the lignad backbone. The readily available ligand 1 as well as analogues with other donor atoms, therefore, appear useful in most potential applications of trans-spanning chelate ligands. The crystal structure of AgCl( 1 )·0.5 (CH₃)₂C?O·0.39 C₆H₁₂ (space group C2/c,a = 21.02 Å, b = 14.57 Å, c = 24.79 Å, β = 99.77°, V = 7531.4 ų, Z = 8) confirms the presence of three-coordinate Ag( I ), with a coordination intermediate between a trigonal-planar and a T-shaped geometry (P-Ag-P = 145.61(8)°).     

A series of complexes of the phosphorus-based TTF ligand o-P2 with the metal ions Fe(II), Co(II), Ni(II), Pd(II), Pt(II), and Ag(I)

Reactions of 3,4-dimethyl-3',4'-bis(diphenylphosphino)tetrathiafulvalene, o-P2, with [BF(4)](-) salts of Fe(ii), Co(ii), Ni(II), Pd(II), and Pt(II) yield complexes of general formula [M(o-P2)(2)][BF(4)](2). Similar reactions between o-P2 and AgSbF(6) or AgPF(6) produced the salts [Ag(o-P2)(2)][X] where X = [SbF(6)](-) or [PF(6)](-). The resulting compounds were fully characterized by (1)H and (31)P{(1)H} NMR, infrared and electronic absorption spectroscopies, cyclic voltammetry, FAB-MS and single-crystal X-ray diffraction. The paramagnetic Co(II) compound exhibits an S = 3/2 state with large spin-orbit coupling contribution at higher temperatures and an effective S' = 1/2 state below 20 K. Electrochemical studies of the compounds indicate that the two functionalized TTF ligands are not in electronic communication and that they essentially behave as isolated redox centers.     

Radiolytic reductions of Ag(I), Cu(II), Hg(II) and Pb(II) in aqueous-ethanol systems and the effect of colloidal sulfur

Radiation-induced reductions in aqueous AgClO₄, CuCl₂, PbCl₂ and HgCl₂ systems have been measured in the presence of ethanol and for Ag(I) and Cu(II) with several other organic components. In dilute solutions and under deaerated conditions, the rates were consistent with known radical yields and rate constants. Approximately one-third of the radicals formed from ethanol under conditions of complete OH scavenging are ineffective in reducing Cu(II). In the presence of colloidal Cu or Ag, all of the radicals are effective in the reduction. In the presence of 0.4–2 × 10^-3 g-atom 1^-1 of colloidal sulfur, sulfur reduction competes with and augments that of Ag(I) and Cu(II). Ag₂S and CuS are formed with a reaction chain occuring in the Ag system at 1.7 M ethanol. A mechanism is suggested that involves reaction of a radical-cation complex at the sulfur-aqueous interface in which the metal sulfide is formed. HgCl₂ reduction is unaffected by colloidal sulfur and that of PbCl₂ is depressed.     

Interaction of Ag(I), Hg(II), and Cu(II) with 1,2-ethanedithiol immobilized on chitosan: thermochemical data from isothermal calorimetry

The nature of interactions between metal ions Ag(I), Hg(II), Cu(II) and chitosan derivative of 1,2-ethanedithiol, QTDT, was investigated by isothermal calorimetry using the membrane breaking technique. Simultaneous determination of thermal effects, Q(int), and amount of cation that interacts, n(int), are described. The experimental data have been interpreted in terms of the Langmuir equation to determine the maximum adsorption capacity to form a monolayer, N(mon), and the energy of interaction for a saturated monolayer per gram of QTDT, Q(mon). With N(mon) and Q(mon), the molar enthalpy of interaction for formation of a monolayer of anchored cations per gram of QTDT, Delta(mon)H(m), was determined. The Delta(mon)H(m) values for Ag(I), Hg(II), and Cu(II) were -60.56, -58.05, and -84.36 kJ mol(-1), respectively. Negative values of DeltaG show the spontaneity of the interaction processes. The least entropically favourable processes, i.e., those which present more negative DeltaS values, seem to be compensated by the more favourable enthalpic parameter.     

Complexes of Ag(I), Hg(I) and Hg(II) with multidentate pyrazolyl-pyridine ligands: From mononuclear complexes to coordination polymers via helicates, a mesocate, a cage and a catenate

The coordination chemistry of a series of di- and tri-nucleating ligands with Ag(I), Hg(I) and Hg(II) has been investigated. Most of the ligands contain two or three N,N'-bidentate chelating pyrazolyl-pyridine units pendant from a central aromatic spacer; one contains three binding sites (2 + 3 + 2-dentate) in a linear sequence. A series of thirteen complexes has been structurally characterised displaying a wide range of structural types. Bis-bidentate bridging ligands react with Ag(I) to give complexes in which Ag(I) is four-coordinate from two bidentate donors, but the complexes can take the form of one-dimensional coordination polymers, or dinuclear complexes (mesocate or helicate). A tris-bidentate triangular ligand forms a complicated two-dimensional coordination network with Ag(I) in which Ag...Ag contacts, as well as metal-ligand coordination bonds, play a significant role. Three dinuclear Hg(I) complexes were isolated which contain an {Hg2}2+ metal-metal bonded core bound to a single bis-bidentate ligand which can span both metal ions. Also characterised were a series of Hg(II) complexes comprising a simple mononuclear four-coordinate Hg(II) complex, a tetrahedral Hg(II)4 cage which incorporates a counter-ion in its central cavity, a trinuclear double helicate, and a trinuclear catenated structure in which two long ligands have spontaneously formed interlocked metallomacrocyclic rings thanks to cyclometallation of two of the Hg(II) centres.     

Study of the Thermal Decompositions on N,N-Dialkyl-N'-Benzoylthiourea Complexes of Cu(II), Ni(II), Pd(II), Pt(II), Cd(II), Ru(III) and Fe(III)

The thermal decompositions of the complexes of N,N-dialkyl-N'-benzoylthioureas with Cu(II), Ni(II), Pd(II), Pt(II), Cd(II), Ru(III) and Fe(III) were studied by TG and DTA techniques. These metal complexes decompose in two stages: elimination of dialkylbenzamide, and total decomposition to metal sulphides or metals. The influence of the alkyl substituents in these benzoylthiourea chelates on the thermal behaviour of the metal complexes was investigated.This revised version was published online in November 2005 with corrections to the Cover Date.     

Tris(2,2′-bipyridyl)iron(II)tetraphenylborate as a solid analytical reagent in the spectrophotometric determination of Ag(I), Tl(I), and Hg(II)

Analytical applications of a new solid reagent tris(2,2′-dipyridyl)iron(II) tetraphenylborate are described. The solid reagent selectively reacts with Ag(I), Tl(I), and Hg(II) cations to release the colored tris(2,2′-bipyridyl)iron(II) cation in solution, which is determined spectrophotometrically. The experimental data show that the Ag(I), Tl(I), and Hg(II) cations respond linearly in 5 to 50-ppm range.     

A robust in vitro Anticancer,Antioxidant and Antimicrobial Agents Based on New Metal-Azomethine Chelates Incorporating Ag(I), Pd (II) and VO (II) Cations: Probing the Aspects of DNA Interaction

A novel azomethine ligand (HNAP) [HNAP = 1-(Pyridin-3-yliminomethyl)-naphthalen-2-ol] and its Ag(I), Pd (II) and VO (II) chelates have been synthesized and structurally inspected using a wide range of spectroscopic and analytical tools, including infra-red (IR), ultraviolet-visible (UV-Vis) and ¹H NMR spectroscopy techniques, CHN analysis, molar conductance, magnetic susceptibility, and thermogravimetric analysis. The molar conductance measurements reveal that the chelates are non-electrolytes. The thermal behavior of the investigated metal chelates shows that the hydrated, coordinated water molecules and the anions are removed in successive steps followed immediately by decomposition of the ligand in the subsequent steps. The activation thermodynamic parameters are calculated from the TG curves and discussed. Complexes formation study via continuous variation m molar ratio has been investigated, and results were consistent to those found in the solid complexes with a ratio of (M:L) as (1:1) or 1:2 (M:L) molar ratio for all the monolithic and bi-valent metal complexes with square planar for Pd (II), and Ag(I) cations while, square pyramidal geometry for VO (II) cation. DFT calculations for the titled different metal-chelates have been studied and showed a good correlation with the experimental data. The prepared compounds had been checked In vitro towards numerous sorts of plant pathogenic fungi and bacteria to evaluate their antimicrobial properties and compared with some known antibiotics. Significantly, all the complexes show excellent antimicrobial activity against various strains of bacteria and fungi, including both Gram-negative and Gram-positive bacteria. Besides, the complexes exhibited high cytotoxicity against various carcinoma cell lines, including HCT-116, MCF-7, and HepG-2. Moreover, the effect of the new synthesized compounds as antioxidants was determined by reduction of 1,1-diphenyl-2-picryl hydrazyl (DPPH) and compared with that of Vitamin C. Furthermore, the binding interactions of the complexes with CT-DNA were explored using UV-Vis spectroscopy, viscosity and gel electrophoreses measurements. They cooperatively bind to DNA possibly through intercalations. The binding ability of the complexes was shown as HNAPAg > HNAPPd > HNAPVO complex.     

Influence of the Degree of Chitosan Sulfoethylation on the Sorption of Palladium(II) Chloride Complexes from Multicomponent Solutions

The influence exerted by the degree of substitution of sulfoethylated chitosan cross-linked with glutaraldehyde on the sorption of Pd(II) chloride complexes from multicomponent solutions containing Pt(IV), Cu(II), Ni(II), Co(II), Cd(II), and Zn(II) was studied. The sorption of transition metal ions under the conditions of the experiment at pH 0.5–5.0 is virtually fully suppressed. The strongest interfering effect on the Pd(II) sorption is exerted by Pt(IV). Calculation of the selectivity coefficients K_Pd/Pt shows that the selectivity of the Pd(II) sorption relative to Pt(IV) increases with an increase in the degree of substitution of chitosan from 0.3 to 0.5. Integral kinetic curves of the Pd(II) sorption were obtained, and the dependences were subjected to mathematical processing using the models of diffusion and chemical kinetics. The equilibrium in the palladium(II) chloride solution–sorbent system is attained within 40 min. Pd and Pt are quantitatively desorbed from the sorbent surface under dynamic conditions with 3.5 M HCl solution.