Synthesis,Structure and Property of One Bis (benzimidazolin-2-ylidene) Arene-mercury(Ⅱ) Complex

Reaction of a N-heterocycliccarbene(NHC) containing an anthracene unit and two N-picolyl moieties with Hg(OAc)2 yielded a novel mercury(Ⅱ) complex(1). X-ray studies, UV-vis and fluorescence spectroscopy confirmed that a strong interaction exists between the mercury atom and anthracene unit.     

A Novel Hg(II) PVC Membrane Sensor Based on Simple Ionophore Ethylenediamine Bis‐Thiophenecarboxaldehyde

Abstract

A mercury (II) ion‐selective polyvinyl chloride (PVC) membrane sensor based on ethylenediamine bisthiophenecarboxaldehyde (EDBT) as a novel nitrogen‐ and sulfur‐containing sensing material was successfully developed. The ionophore was produced through Schiff's base formation between ethylenediamine and 2‐thiophenecarboxaldehyde. These two reagents have the advantages of low cost and simple chemical compounds. Ortho‐nitro phenyl pentyl ether (o‐NPPE) as solvent and sodium tetraphenyl borate (NaTPB) as a lipophilic salt were chosen. The sensor exhibited a good linear response of 30.0±0.4 mV per decade within the concentration range of 10^?7–10^?2 and a detection limit of 7.0×10^?8 mol L^?1 Hg(II). The sensor showed good selectivity and fast response for the mercury (II) ion with respect to some alkali, alkaline earth, transition, and heavy metal ions. The EDBT–based sensor was suitable for aqueous solutions of pH range from 2.0 to 4.5. It can be used for about 3 months without any considerable divergence in potential. The formation constant of ionophore complex with Hg(II) ion was calculated by using the segmented sandwich membrane method. The structure of both the ionophore and its Hg(II) complex were examined using infrared spectra and elemental analysis. The proposed sensor was applied for the determination of Hg(II) content in some dental amulgum alloys and as an indicator electrode for potentiometric titration of Hg(II) ion with EDTA solution, as well as with I^?, OH^?, and IO₃ ^? ions. In addition, the solubility products of the previous ions were determined by using this sensor.     

Porous Polymeric Substrates Based on a Styrene–Divinylbenzene Copolymer for Reversed-Phase and Ion Chromatography

Moscow University Chemistry Bulletin - This review is devoted to the most hydrolytically stable and widely used polymeric substrates based on a styrene–divinylbenzene copolymer (PS–DVB)...     

Highly Selective Potentiometric Oxalate Ion Sensors Based on Ni(Ⅱ) Bis-(m-aminoacetophenone)ethylenediamine

A plasticized PVC (polyvinyl chloride) membrane based oxalate ion selective electrode has been developed by using the condensation product of m‐aminoacetophenone and ethylenediamine. The transition metal complexes of the ligand N,N′‐bis(m‐aminoacetophenene)ethylenediamine (L) were synthesized and incorporated as ionophore for the synthesis of oxalate ion selective electrodes. Most appropriate result in terms of dynamic range, detection limit and response behavior was determined for the Ni(II) bis‐(m‐aminoacetophenone)ethylenediamine complex. The electrode demonstrated higher selectivity for oxalate ion with improved performance as compared to other carriers reported in past. The electrode shows Nernstian slope of (?28.5±0.4) mV·decade^?1 with improved linear range of 1×10^?1?1×10^?7 mol·L^?1, with a comparatively lower detection limit in the pH range of 5–10.5, giving a relatively fast response within 10 s and reasonable reproducibility. The selectivity coefficient was calculated using matched potential method and fixed interference method. The lifetime of the electrode was found to be nearly 2 months. The response mechanism and the interaction of oxalate ion with the complexes have been discussed by UV‐visible spectroscopic technique. Further the electrode was also successfully applied to determine the oxalate content in water samples.     

Hydrothermal Synthesis,Crystal Structure and Fluorescent Property of a Cd(Ⅱ) Complex Based on Biimidazole and Isonicotinate-N-oxide

A new complex [Cd(H2biim)2(H2O)2]·(ino)2·4H2O (H2biim = 2,2'-biimidazole, ino = isonicotinate-N-oxide) has been prepared and characterized by single-crystal X-ray diffraction analysis, IR and fluorescence spectra analysis. The crystal is of triclinic system, space group P1 with a = 7.5380(6), b = 8.0402(7), c = 13.5094(11) , α = 104.269(1), β = 93.604(1), γ = 98.349(1)°, V = 780.93(11) 3, Mr = 765.00, Dc = 1.627 g/cm3, F(000) = 390, μ = 0.776 mm-1 and Z = 1. The final R = 0.0322 and wR = 0.0825 for 7038 observed reflections with I 2σ(I) and R = 0.0341 and wR = 0.0832 for all data. The title complex exhibits an infinite chain-like structure through bridging isonicotinate-N-oxide. Strong interchain hydrogen bonds between isonicotinate-N-oxide and H2biim result in the robust 3-D supramolecular architecture. Moreover, the complex shows strong photoluminescence with emission maximum at λ = 401 nm upon λex = 330 nm.     

Structure and Luminescent Property of a Tetrahedral Silver(Ⅰ) Cluster Complex Based on Phosphor and Sulphur Mixed-ligand System

A tetrahedral silver(I) cluster complex {Ag_4[HC(PPh_2)_3](S_2PPh_2)_3}ClO_4(1,HC(PPh_2)_3 = 1,1,1-tris(triphenylphosphino)methane, S_2PPh_2 = diphenyldithiophosphinate) was synthesized by assembling silver ion with phosphor and sulphur mixed-ligand system. The complex was characterized by single-crystal X-ray crystallography, high-resolution mass spectroscopy and thermal analysis. In the crystal structure, an inverted tetrahedron was constructed from Ag4 metal skeleton. The Ag4 cage was stabilized by three diphenyldithiophosphinate ligands and one 1,1,1-tris(triphenylphosphino)methane ligand. 1 exhibits luminescent properties in solid state. A bright yellow-green emission centered at 533 nm has been observed in solid state. Large Stokes' shifts with long range of emissive lifetime indicate that the emission likely originates from a triplet state parentage.     

Study of the Structure and Reactions of Bis(μ-Oxalato)tetramminediplatinum(II) in Aqueous Chloride Solutions

A comparison study of the bis(-oxalato)tetramminediplatinum(II) dimer [Pt₂(NH₃)₄(-C₂O₄)₂] and the oxalatodiammineplatinum(II) chelate [Pt(NH₃)₂C₂O₄] is performed. The kinetics and mechanism of substitution of C₂O^2– ₄ for Cl^– in aqueous chloride solutions are studied by photoelectronic spectroscopy, gravimetry, and chemical phase analysis within the 1.0–6.7 pH range at 75°C. The rate constants of substitution and the equilibrium constants for a two-step protonation for the dimeric and chelate complexes are calculated. Their solubility in 1 M KCl at 75°C; is determined. The unit cell parameters for [Pt₂(NH₃)₄(-C₂O₄)₂] are determined: a = 3.858 Å, b = 10.704 Å, c = 6.795 Å, = 94.35°. The IR spectra of [Pt(NH₃)₂C₂O₄], [Pt₂(NH₃)₄(-C₂O₄)₂], and their deuterated analogs are studied.     

Synthesis,Crystal Structure and Luminescent Property of a Zn(Ⅱ) Complex Based on 4-Imidazole-carboxylate Ligand

A new complex, [Zn(L)_2](1), has been hydrothermally prepared by the reaction of ZnSO_4·7H_2O with 2-(1H-imidazol-4-yl)benzoic acid(HL) incorporating 4-imidazolyl and carboxylate functional groups, and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and powder X-ray diffraction(PXRD). Complex 1 crystallizes in monoclinic, space group C2/c with a = 9.8349(9), b = 7.4947(7), c = 24.104(2) ?, β = 92.889(2)o, V = 1774.4(3) ?~3, Z = 4, C_(20)H_(14)N_4O_4 Zn, M_r = 439.72, D_c = 1.646 g/cm~3, μ = 1.422 mm~(-1), S = 1.003, F(000) = 896, the final R = 0.0395 and wR = 0.0874 for 11386 observed reflections(I 2σ(I)). Single-crystal X-ray structural analysis reveals that complex 1 features a two-dimensional(2D) framework with 6~3-hcb topology. Moreover, the photoluminescent property of 1 was also discussed.     

Investigation on the Thermostability of Germanium and Elimination of Chloride and Sulfate.Interference on Germanium in Graphite Furnace Atomic Absorption Spectrometry

TheadvantageofdeterminationoftraceGebyGF.AASisthatonlyafewmicrolitersofsampleisused.Butthematrixinterference,especiallychlorideionandsulfateionisveryseriousl.Sothereisanimportantsubjectforfurtherinvestigatingtoeliminatetheseinterferences.Nitricacidisanoxidant.ThetetravalentGeisstabilizedowingtoitsoxidation.ThemagnitudeoftheGesignalvarieswiththeconcentrationofnitricacidandthemaximumoftheGesignalisobservedwith0.6mol/Lnitricacid.Theactionofsomenitratesissimilarbuttheconcentrationofvariousnit…     

Synthesis,Crystal Structure and Redox Property of a Copper(Ⅱ) Complex Based on 1,1-Bis(1H-benzoimidazol-2-ylmethyl)cyclohexane

A novel mononuclear copper(Ⅱ) complex [Cu(bbmc)Cl_2]·DMF,where bbmc is 1,1-bis(1H-benzoimidazol-2-ylmethyl)cyclohexane,was synthesized and characterized by X-ray single-crystal structure analysis.The complex crystallizes in triclinic,space group P1 with a = 9.1088(5),b = 11.0075(4),c = 14.2326(6) ?,α = 97.188(3),β = 96.394(4),γ = 111.430(4)°,V = 1298.73(10) ?~3,Z = 2,D_c = 1.409 g/cm~3,μ(Mo Kα) = 1.074 mm~(-1),F(000) = 572,S = 1.078,R = 0.0381 and w R = 0.0876 for 5593 observed reflections with I 2σ(I).The central Cu(Ⅱ) ion adopts a distorted tetrahedral geometry coordinated by two nitrogen atoms of the ligand and two chloride ions.The complex showed its thermal decomposition temperature up to 226 ℃ and exhibited an irreversible one-electron transfer process involving Cu~(Ⅱ)/Cu~I couple.     

Synthesis and properties of double copper(I)–nickel(II) sulfite

Pourbaix diagrams of Cu–H₂SO4–H₂O and Ni–H₂SO₄–H₂O systems have been refined, and stability regions of the sulfite phases have been determined. State diagrams of double copper(I)–copper(II) and copper(I)–nickel(II) sulfites have been constructed. Double copper(I)–nickel(II) sulfite has been isolated from aqueous solutions saturated with sulfur dioxide. The solutions at different ratios of the metals have been studied by spectrophotometry; the isolated double sulfite has been studied by X-ray diffraction, IR spectroscopy, dispersion analysis, and thermal analysis. Fundamentals of thermodynamic prognostication of the Cu₂SO₃·MSO₃ double sulfites synthesis have been elaborated.     

Synthesis,Crystal Structure and DNA-Binding Property of a Mn(Ⅱ) Complex Based on 5-(Tri-fluoromethyl)pyridine-2-carboxylic Acid

A new complex Mn(Htpc)_2(H_2O)_2(1, Htpc = 5-(trifluoromethyl)pyridine-2-carboxylic acid) has been synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. 1 belongs to triclinic system, space group P■ with a = 5.0885(10), b = 6.5574(13), c = 14.016(3) ?, β = 90.67(3)o, V = 436.34(17) ?~3, Z = 1, D_c = 1.793 g·cm~(-3), μ = 0.855 mm~(-1), Mr = 471.18, F(000) = 235, the final R = 0.0454 and wR = 0.1134 for 1998 observed reflections with I 2σ(I). The Mn(Ⅱ) ion is coordinated by two N and two O atoms from two Htpc as well as two O atoms from two coordinated water molecules, forming a 0D motif with distorted octahedral coordinate geometry. The adjacent 0D units are linked into 1D chains through hydrogen bond O(1W)–H(1 WB)···O(2), and via the O(1 W)–H(1 WA)···O(1) hydrogen bond the neighboring 1D chains are connected into a 2D supramolecular layer. Moreover, the interactions between the ligand and its complex with CT-DNA were studied by EtBr fluorescence probe, which suggested that these compounds bind to CT-DNA through an intercalation mode. The binding constants were 0.41 and 0.64 for Htpc and complex 1, respectively. It indicates that the interaction between complex 1 and CT-DNA is stronger than Htpc.     

Bis Crown Ethers( Ⅸ)——Caesium Selective PVC Membrane Electrodes Based on Schif f Base Type of Bis Crown Ethers

Recently, much attention has been focused on the use of neutral carrier species as membrane components to extract ions from aqueous solution into a hydrophobic membrane phase. Some potassium-or caesium-selective electrodes based on bis-benzo-15-crown-5 or bis-benzo-18-crown-6 containing ester or other linkage were prepared by K. Kimura and K. W. Fung. The selective coefficients K_(K,Na)~(pot), K_(Cs,Na)~(pot),or K_(Cs,K)~(pot), K were 2.6×10~(-4), 1.9×10~(-2) and 1.7×10~(-1), respectively.     

Molecular and Supramolecular Structures of a Nickel(II)–Copper(II)–Nickel(II) Trinuclear Complex Containing a New Macrocyclic Oxamido Complex Ligand

The title complex, [Cu(NiL)₂(H₂O)₂](ClO₄)₂, has been obtained by self-assembly, where [NiL] is a new macrocyclic oxamido complex ligand. In the crystal, a new kind of supramolecular interaction between the carbon atoms of the oxamido group of each [NiL] complex ligand in a [Cu(NiL)₂(H₂O)₂]^{2 +} cation and the oxygen atom of one of the ester carbonyls of another [Cu(NiL)₂(H₂O)₂]^{2 +} cation, and C—HO, O—HO and interactions are observed and link the trinuclear fragments and perchlorate ions to form a 3D supramolecular network.     

Cobalt(II) Chloride Complex Formation in Acetamide–Calcium Nitrate Tetrahydrate Melts

The absorption spectra of Co(II) chloride complexes, containing variable concentrations of chloride ligand, in a molten mixture of 80 mol% acetamide–20 mol% calcium nitrate tetrahydrate, were studied at 313, 333, 353, and 363 K, in the wavelength range 400-800 nm. The melt contains three possible ligands (CH₃CONH₂, H₂O, and NO₃ ^-) for competition with added chloride ligand. Addition of chloride caused a shift of the absorption maximum of octahedral cobalt(II) nitrate towards lower energies and pronounced changes in the shape of the initial spectrum of cobalt(II) nitrate. The effect of temperature changes on the molar absorption coefficient of the Co(II) species was dependent on the chloride concentration and was attributed to the structural changes occurring in the cobalt(II) species. The STAR and STAR FA programs were applied to identify the complex ionic species and to calculate the stability constants of Co(II) complexes formed in this solvent. The results indicate the highest probability of formation of the following complex species: Co(NO₃)₄ ^2-, Co(NO₃)₂Cl₂ ^2-, and CoCl₄ ^2-. Stability constants of each complex were presented for the equilibria occurring at 313, 333, 353, and 363 K. Distribution of the Co(II) species was also calculated over the ranges of chloride concentration and temperature investigated.     

Highly Selective Thiocyanate Electrode Based on Bis‐bebzion Schiff Base Binuclear Copper(II) Complex as Neutral Carrier

Abstract

A highly selective polyvinyl chloride (PVC) membrane electrode, based on N,N′‐(aminoethyl)ethylenediamide bis(2‐benzoideneimine) binuclear copper(II) complex [Cu(II)‐AEBB] as neutral carrier, was prepared for thiocyanate (SCN^?) determination, which displays an anti‐Hofmeister selectivity sequence for a series of anions in the following order: SCN^?>ClO₄ ^?>Sal^? > I^?>NO₃ ^?>Br^?> Cl^?>NO₂ ^?>SO₃ ^2?>F^?>H₂PO₄ ^?>SO₄ ^2?. The electrode exhibited near‐Nernst response for SCN^? with a slope of –59.0 mV/decade over a wide concentration range (8.5×10^?7～6.8×10^?1 mol/L) with a detection limit of –5.0×10^?7 mol/L in pH 5.0 phosphate buffer solution at 25°C. Alternating current (AC) impedance and equivalent circuits were used to investigate the thiocyanate response mechanism of the membrane doped with [Cu(II)‐AEBB].     

Synthesis and Structures of Dinuclear Aluminum Complexes Based on Bis(β-diketiminate) Ligands

A series of ten dinuclear aluminum alkyl complexes based on rigid, semirigid, and flexible bis(β-diketiminate) ligands (NacNac) has been obtained from the reaction of trimethylaluminum and the corresponding bis(β-diketimine)s. All compounds were fully characterized using NMR and IR spectroscopy and elemental analysis. The molecular structures of five compounds have been investigated by means of single-crystal X-ray diffraction analysis.     

Crystal Structures and Characterizations of Bis(pyrrolidinedithiocarbamato) Cu(II) and Zn(II) Complexes

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Highly Selective Salicylate Membrane Electrode Based on N,N′-(Aminoethyl)ethylenediamide Bis(2-salicylideneimine)Binuclear Copper(Ⅱ) Complex as Neutral Carrier

A new ion selective electrode for salicylate based on N,N'-(aminoethyl)ethylenediamide bis(2-salicylideneimine)binuclear copper(Ⅱ)complex[Cu(Ⅱ)_2-AEBS]as an ionophore was developed.The electrode has a linear range from1.0×10~(-1) to 5.0×10~(-7) mol·L~(-1) with a near-Nernstian slope of(-55±1)mV/decade and a detection limit of 2.0×10~(-7) mol·L~(-1) in phosphorate buffer solution of pH 5.0 at 25℃.It shows good selectivity for Sal~- and displaysanti-Hofmeister selectivity seoquence:Sal~->SCN~->ClO_4~->I~->NO_2~->Br~->NO_3~->CI~->SO_3~(2-)>SO_4~(2-)The proposed sensor based on binuclear copper(Ⅱ)complex has a fast response time of 5-10 s and can be used forat least 2 months without any major deviation.The response mechanism is discussed in view of the alternating cur-rent(AC) impedance technique and the UV-vis spectroscopy technique.The effect of the electrode membranecompositions and the experimental conditions were studied.The electrode has been successfully used for the deter-mination of salicylate ion in drug pharmaceutical preparations.