In The Nickel Research Articles

Nickel(ii) and mixed metal complexes of amyloid-β N-terminus

Nickel(II) complexes of Abeta(1-16)Y10A and its smaller fragments including Abeta(1-4), Abeta(1-6), Ac-Abeta(1-6) and Ac-Abeta(8-16)Y10A have been studied by potentiometric, UV-Vis and circular dichroism spectroscopic measurements. The formation of mixed metal complexes and the distribution of metal ions among the possible coordination sites in the Cu(II)-Ni(II)-Abeta(1-16)Y10A and Cu(II)-Ni(II)-Zn(ii)-Abeta(1-16)Y10A systems have also been evaluated. It was found that the hexadecapeptide and its fragments are effective nickel(II) binding ligands and complex formation processes of nickel(II) ions are quite similar to those of copper(II). Formation of mono- and di-nuclear complexes was detected in the nickel(II)-Abeta(1-16)Y10A system suggesting the existence of two separated metal binding motifs: the N-terminus and internal histidyl residues. The preference for the coordination at the N-terminus was supported by the spectroscopic measurements but in equilibrium with the metal binding at the internal histidyl sites. Neither zinc(II) nor nickel(II) can, however, substitute copper(II) in the mixed metal complexes of Abeta(1-16)Y10A, but both metal ions are able to alter the distribution of copper(II) ions among the various binding sites. Both N-terminus (amino and His6) and internal histidyl residues (His13 and His14) can work as dinuclear binding motifs, preferably accommodating copper(II) and zinc(II), respectively, while nickel(II) can occupy the remaining free coordination sites.

Unsymmetrical one-electron oxidized Ni(ii)–bis(salicylidene) complexes: a protonation-induced shift of the oxidation site

The spin density in the nickel(II) radical salen complex (2*)(+) could be localized on a specific ring by controlling the acidity of the medium.

New 3D Coordination Polymers Constructed from Pillared Metal−Formate Kagomé Layers Exhibiting Spin Canting Only in the Nickel(II) Complex

Sparked by the strategy of pillared-layer MOFs, three formate coordination polymers, {[Ni(2)(HCO(2))(3)(L)(2)](NO(3)).2H(2)O}(infinity) (1), {[Co(2)(HCO(2))(3)(L)(2)](HCO(2)).2H(2)O}(infinity) (2), and {[Cu(2)(HCO(2))(3)(L)(2)](HCO(2)).2H(2)O}(infinity) (3), have been synthesized by employing the rodlike ligand 4,4'-bis(imidazol-1-yl)biphenyl (L) as the pillar. Structural analysis indicates that the title complexes 1-3 are isostructural compounds, which possess metal-formate 2D layers perpendicularly pillared by the ligand L to afford a 3D open framework. This is an interesting example of a Kagome lattice based on the formate mediator. Moreover, the formate anion of this 2D Kagome layer exhibits various bridging modes: anti-anti, syn-anti, and 3.21 modes. Their magnetic measurements reveals that only complex 1 presents the spin canting phenomenon, while its isostructural Co(II) and Cu(II) complexes are simply paramagnets with antiferromagnetic coupling.

Syntheses and crystal structures of nickel(II), copper(II), and zinc(II) complexes with a biphenyl-bridged bis(pyrrole-2-yl-methyleneamine) ligand

The reactions of nickel(II), copper(II), and zinc(II) acetate salts with a potentially tetradentate biphenyl-bridged bis(pyrrole-2-yl-methyleneamine) ligand yielded three complexes with different coordination geometries. X-ray crystal structural analysis reveals that in the nickel(II) complex each nickel is five-coordinate, distorted trigonal bipyramid. In the copper(II) complex, each copper is four-coordinate, between square planar and tetrahedral. In the zinc(II) complex, each zinc is four-coordinate with a distorted tetrahedral geometry and the molar ratio of the zinc and ligand is 1 : 2.

Thermodynamic characteristics of complex formation in the nickel(II) ion-β-alanine systems in aqueous solution

Heats of reactions between a nickel(II) ion and β-alanine were measured calorimetrically at 288.15, 298.15, and 308.15 K and ionic strengths of 0.5, 1.0, and 1.5 (KNO3). Thermochemical data were processed with account for stepwise equilibria; attendant protolytic processes were taken into account together with complexing reactions. Extrapolation to the zeroth ionic strength with the use of a one-parameter equation gave standard thermodynamic characteristics of complex formation in the system. The influence of the supporting electrolyte and temperature on the heats of complex formation reactions was considered. Standard enthalpies of formation were calculated for NiAla+, NiAla2, and NiAla3− species.

Complexing processes in M(II)-dithiomalonamide-diacetyl triple systems (M= Ni, Cu) in ethanol solution and in a metal(II)hexacyanoferrate(II) gelatin-immobilized matrix materials

The complexing processes in the MII-dithiomalonamide-diacetyl triple system (M=Ni, Cu) occuring in the nickel(II)- and copper(II)hexacyanoferrate(II) gelatin-immobilized matrix in contact with aqueous alkaline solutions (pH~12) containing dithiomalonamide and diacetyl at room temperature, and between MCl2, dithiomalonamideanddiacetylinEtOHsolutionsuponheatingto$80 °C, have been studied. In the NiII-dithiomalonamide-diacetyl system, template synthesis occurs in EtOH solution but does not occur in the gelatin-immobilized matrix, whereas in the CuII-dithiomalonamide-diacetyl system, template synthesis occurs in the gelatin-immobilized matrix but not in EtOH solution. Dithiomalonamide and diacetyl are the ligand synthons in the processes indicated.

Removal and recovery of nickel(II) from aqueous solution by loofa sponge-immobilized biomass of Chlorella sorokiniana: characterization studies

The biosorption process for the removal of nickel(II) by loofa sponge-immobilized biomass of Chlorella sorokiniana (LIBCS), a newly developed immobilized biosorbent, was characterized. Effects of environmental factors on metal uptake capacity of LIBCS were studied and compared with free biomass of C. sorokiniana (FBCS). Nickel(II) removal by LIBCS was found to be influenced by pH of the solution, initial metal concentration, and biomass concentration. The biosorption of nickel(II) ions by both LIBCS and FBCS increased as the initial concentration of nickel(II) ions increased in the medium. No loss to biosorption capacity of LIBCS for nickel(II) was found due to the presence of loofa sponge, indeed as compared to FBCS an increase of 25.3% was noted in the biosorption capacity of LIBCS. Maximum biosorption capacities for FBCS and LIBCS were found as 48.08 and 60.38 mg nickel(II)/g, respectively, whereas the amount of nickel(II) ions adsorbed on the plain loofa sponge was 6.1 mg/g. During these biosorption studies, LIBCS exhibited excellent physical and chemical stability without any significant release/loss of microalgal biomass from loofa sponge matrix. The kinetics of nickel(II) removal was extremely fast reaching at equilibrium in about 15 min for LIBCS and 20 min for FBCS. The biosorption equilibrium was well described by the Langmuir and Freundlich adsorption isotherms. The biosorption capacities were found to be solution pH dependent and the maximum adsorption was found at a solution pH 4–5. The LIBCS could be regenerated using 75 mM HCl, with up to 98% recovery. The LIBCS were shown to be robust and stable with little decrease in the nickel(II) uptake capacity when used in consecutive seven biosorption–desorption cycles. Continuous removal of nickel(II) from electroplating effluent by LIBCS packed in fixed bed column bioreactor confirm the possibility of developing a biological treatment process for the removal of toxic metals from authentic wastewater.

PH-controlled fluorescent emission in the nickel(II) complex of a bifunctional tetramine macrocycle.

In the Ni(II) complex of a reinforced tetramine macrocycle, equipped with both a sulfonamide pendant arm and a naphthalene fragment, light emission of the fluorophore is pH-controlled, as a result of a change of the geometry of the complex.

Kinetics and mechanism of complex formation of nickel(II) with tetra-N-alkylated cyclam in N,N-dimethylformamide (DMF): comparative study on the reactivity and solvent exchange of the species Ni(DMF)6(2+) and Ni(DMF)5Cl+.

13C NMR was used to study the rate of DMF exchange in the nickel(II) cation Ni(DMF)6(2+) and in the monochloro species Ni(DMF)5Cl+ with 13C-labeled DMF in the temperature range of 193-395 K in DMF (DMF = N,N-dimethylformamide). The kinetic parameters for solvent exchange are kex = (3.7 +/- 0.4) x 10(3) s-1, delta H++ = 59.3 +/- 5 kJ mol-1, and delta S++ = +22.3 +/- 14 J mol-1 K-1 for Ni(DMF)6(2+) and kex = (5.3 +/- 1) x 10(5) s-1, delta H++ = 42.4 +/- 4 kJ mol-1, and delta S++ = +6.7 +/- 15 J mol-1 K-1 for Ni(DMF)5Cl+. Multiwavelength stopped-flow spectrophotometry was used to study the kinetics of complex formation of the cation Ni(DMF)6(2+) and of the 100-fold more labile cation Ni(DMF)5Cl+ with TMC (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) and TEC (1,4,8,11-tetraethyl-1,4,8,11-tetraazacyclotetradecane) in DMF at 298 K and I = 0.6 M (tetra-n-butylammoniumperchlorate). Equilibrium constants K for the addition of the nucleophiles DMF, Cl-, and Br- to the complexes Ni(TMC)2+ and Ni(TEC)2+ were determined by spectrophotometric titration. Formation of the complexes Ni(TMC)2+ and Ni(TEC)2+ was found to occur in two stages. In the initial stage, fast, second-order nickel incorporation with rate constants k1(TMC) = 99 +/- 5 M-1 s-1 and k1 (TEC) = 235 +/- 12 M-1 s-1 leads to the intermediates Ni(TMC)int2+ and Ni(TEC)int2+, which have N4-coordinated nickel. In the second stage, these intermediates rearrange slowly to form the stereochemically most stable configuration. First-order rate constants for the one-step rearrangement of Ni(TMC)int2+ and the two-step rearrangment of Ni(TEC)int2+ are presented. Because of the rapid formation of Ni(DMF)5Cl+, the reactions of Ni(DMF)6(2+) with TMC and TEC are accelerated upon the addition of tetra-n-butylammoniumchloride (TBACl) and lead to the complexes Ni(TMC)Cl+ and Ni(TEC)Cl+, respectively. For initial concentrations such that [TBACl]o/[nickel]o > or = 20, intermediate formation is 230 times (TMC) and 47 times (TEC) faster than in the absence of chloride. The mechanism of complex formation is discussed.

Copper(II) and nickel(II) metallopolymers derived from polyacylhydrazones

A series of polyacylhydrazones derived from condensing diacetyl with oxalic, malonic, succinic, glutaric and adipic dihydrazides was prepared, characterized and reacted with copper(II) and nickel(II) acetate to give metallopolymers of general formula [Cu2(L)(AcO)2(OH)(H2O)2] · yH2O n , [Cu(L)(AcO)(HO)(H2O)] · yH2O n , [Ni2(L)(AcO)2-(HO)2] · yH2O n and [Ni(L)(AcO)(HO)] · yH2O n , where L refers to the neutral dihydrazone unit. Magnetic susceptibility measurements in the 4.2–300 K range indicate significant antiferromagnetic coupling between the CuII centers in the metallopolymers, which may indicate the presence of two polymer chains crosslinked by bis-μ-acetatocopper(II) bridges. Based on i.r., spectral and magnetic measurements, tentative structures of the CuII and NiII metallopolymers have been proposed. The dihydrazone units in these polymers are coordinated to the metal(II) via the azomethine nitrogen(s) whereas the amide group remains uncoordinated. Each CuII is penta-coordinated in a distorted square pyramidal environment and is neutralized by one bridged acetate and a hydroxide ion, while the fifth coordination site is occupied by a water molecule. In the nickel(II) metallopolymers the metal ions are in a tetrahedral environment and are coordinated to azomethine nitrogen, two bridged acetate oxygens and to the hydroxide ion.

Unusual Ligand Isomerization Dictated by Coordination Requirements of the Metal Ion: A Double-Bond Shift in Cu(II)-Assisted Template Condensation between Diacetylpyridine and a Tripodal Tetramine.

This paper reports a new effect in template-directed Schiff base condensation, a "fine-tuning" of the macrocyclic structure in accordance with the precise coordination requirements of the metal ion. The nature of the metal template determines the outcome of Schiff base condensation between a difunctional carbonyl component (2,6-diacetylpyridine) and a trifunctional amine component (tris(3-aminopropyl)amine, trpn). Both Cu(II) and Ni(II) facilitate [1 + 1] condensation with the formation of macrocyclic products in 50-60% yield, but single-crystal X-ray diffraction reveals that the chemical structure of the major product is metal-ion dependent. In the nickel(II) complex [Ni(L(sym))](2+), the C=N double bonds are conjugated with the pyridine ring, as expected from the structure of the starting diacetylpyridine. In contrast, the copper(II) ion caused isomerization of the macrocyclic ligand, with one of the C=N double bonds migrating into the initially saturated six-membered chelate ring forming [Cu(L(asym))](2+). The second product isolated, in small quantities, from the copper(II)-templated condensation has been characterized as an isomeric symmetric macrocycle [Cu(L(sym))](2+). In the case of the zinc(II) template, no macrocyclic product has been isolated; instead, a zinc(II) complex of the starting tetramine, Zn(trpn)Cl(2).2H(2)O, was recovered and structurally characterized. An unusual double-bond migration in the course of Cu(II)-directed template condensation is governed by the coordination requirements of the central metal ion. The asymmetric ligand isomer is more flexible than its symmetric counterpart and can therefore better accommodate the five-coordinate central metal ion. This effect is more pronounced for the copper(II) complex than for the nickel(II) complex, because of shorter in-plane M-N distances in the former, as follows from the X-ray structure determination. The position of the double bond in the macrocyclic ring influences the spectral properties of the copper(II) complexes and the ionization constants of the amino group in the side arm.

Enantioselective catalysis. Part 102 . Epimerization of glucose and mannose in the presence of nickel(II) complexes of optically active ligands

The epimerization reaction glucose ⇌ mannose, catalyzed by nickel(II) complexes, was investigated. The achiral ligand N,N,N′,N′-tetramethyl-1,2-diaminoethane 1 and the chiral ligands ( R,R)- and (S,S)-N,N,N′,N′-tetramethyl-1,2-diamino-1,2-diphenylethane 2 and 3 were used. The standard epimerization of glucose and mannose, respectively, was carried out in methanol at 60°C using a stoichiometric amount of nickel(II) complex. The influence of substoichiometric and overstoichiometric amounts of the catalyst and the temperature and time dependence were studied. Some of the kinetic and thermodynamic parameters turned out to be dependent on whether the ( R,R)- or ( S,S)-ligand 2 or 3 was used in the nickel(II) complex. The data were subjected to a Michaelis-Menten and Eyring analysis.

Copper(II), nickel(II) and zinc(II) complexes of N, N′, N″, N″'-tetrakis(2-hydroxypropyl)-1,4,8,11-tetra-azacyclotetradecane. Rates of formation and dissociation of the copper(II) complex

The preparation of the pendant arm macrocycle N, N′, N″, N″'-tetrakis(2-hydroxypropyl)-1,4,8,11-tetra-azacyclotetradecane (THPC = L) by reaction of propylene oxide with 1,4,8,11-tetra-azacyclotetradecane (cyclam) is described. Copper(II), nickel(II) and zinc(II) complexes of the ligand have been prepared and characterized. The reaction of L with copper(II) in basic solution has been studied by stopped flow techniques L+[Cu(OH) 3] −→[CuL] 2+; k 1 L+[Cu(OH) 4] 2−→[CuL] 2+; k 1 . At 25°C and I = 1.0 mol dm −3, k 1 = 3.7 × 10 5 and k 2 = 2.1 × 10 4 dm 3 mol −1 s −1. These values may be compared with the constants obtained for cyclam, k 1 = 2.7 × 10 6 and k 2 = 3.8 × 10 4 dm 3 mol −1 s −1 at 25°C. The mechanism of the reaction is discussed. The copper(II) complex [CuL] 2+ dissociates readily in acidic solution. The kinetics of dissociation have been studied by stopped flow methods in the acidity range 0.05–1.0 mol dm −3 HClO 4. Two reactions could be detected, the first reaction was complete within 20–30 ms at 25°C and was attributed to a pre-equilibrium protonation step. The second reaction, associated with an absorbance decrease was assigned to the acid dissociation step and was acid dependent at low acidities and acid independent at high acidities. In the acidity range used the dissociation can be fitted to the kinetic scheme [CuL] 2++H +⇌[CuLH] 3+; K [CuLH] 3+→Cu 2++LH +; k and k obs = kK[H +]/(1 + K[H +]), with k = 7.1 ± 0.4 s −1 and K = 1.3 ± 0.1 dm 3 mol −1 at I = 1.0 mol dm −3 and 25°C. The p K values of THPC determined by potentiometric titration are 9.08, 8.30, < 2 and < 2 at 25°C. Studies of the solution equilibria of the ligand with copper(II) and nickel(II) by potentiometric methods indicate that with copper(II) the titration data can be fitted to the single equilibrium Cu 2+ + L ← CuL 2+ with log β 110 = 15.54(3). In the case of nickel(II) deprotonation of the complex occurs with log β 110 = 7.32(3), log β 11-1 = −1.71(3) and log β 11-2 = −12.62(4). Deprotonation of the pendant hydroxyl groups in the nickel(II) complex has been confirmed by visible spectral measurements.

Remarkable ‘edge’ ligation of a triphosphacyclopentenyl ring system. Synthesis, crystal and molecular structure of [Ni(η5-P3C2But2 ){η2-P3C2But 2CH(SiMe3)2Me}

In the nickel(II) complex [Ni(η 5 -P 3 C 2 Bu t 2 )(η 2 -P 3 C 2 Bu t 2 CH(SiMe 3 ) 2 Me}] the triphosphacyclopentenyl ring P 3 C 2 Bu t 2 CH(SiMe 3 ) 2 Me is unexpectedly coordinated to the metal exclusively via the two adjacent saturated ring phosphorus atoms, rather than via the 2-phosphaallyl fragment.

Spectrophotometric study of thiocyanato complexation of cobalt(II) and nickel(II) ions in micellar solutions of a nonionic surfactant triton X-100

Complexation of cobalt(II) and nickel(II) with thiocyanate ions has been studied by precise spectrophotometry in aqueous and micellar solutions of a nonionic surfactant Triton X-100 of varying concentrations (20–100 mmol-dm−3). With regard to cobalt(II), the formation of [Co(NCS)]+, [Co(NCS)2], and [Co(NCS)4]2− was established. The formation constant of [Co(NCS)4]2−, is increased with increasing concentration of the surfactant, suggesting that the [Co(NCS)4]2− complex is formed in micelles. In contrast, the formation constants of [Co(NCS)]+ and [Co(NCS)2] are remained practically unchanged. On the other hand, with nickel(II), the formation of sole [Ni(NCS)]+ and [Ni(NCS)2] was established in both aqueous and micellar solutions examined, their formation constants being also remained unchanged. Interestingly, no higher complex was confirmed in the nickel(II) system, unlike cobalt(II). The unusual affinity of the [Co(NCS)4]2− complex with micelles will be discussed from thermodynamic and structural points of view.

Crystal structures of trans-di(2-fluorobenzoato- O)di- (1,3-diaminopropane- N, N′)nickel(II) and its copper(II) analogue. Variation in the coordination modes

The structures of di(2-fluorobenzoato- O)di(1,3-diaminopropane- N, N′)copper(II) ( 1) and trans-di(2-fluorobenzoato- Obis(1,3-diaminopropane- N, N′)nickle(II) ( 2) were determined by single-crystal X-ray methods. 1: [Cutn 2(2FbzO 2] (tn = 1,3,-diaminopropane 2FbzO = ortho-fluorobenzoate), C 20H 28F 2CuN 4O 4, M 1 = 490.01, monoclinic, space group P2 1/ n No. 14 a = 15.189(3), b = 8.446(4), c = 26.846(4) A ̊ , β = 106.20(1)°, V = 3307(2) A ̊ 3, Z = 6, D c = 1.476 g cm −3 2: [Ni(tn) 22FBzO) 2], C 20F 2NiN 4O 5, M t = 485.15 , monoclinic, space group P2 1/ a No. 14, a = 11.280(2), b = 8.423(2), c = 11.568(3) A ̊ , β = 96.37(2), V = 1092.3(9) A ̊ 3, Z = 2, D = 1.512 g cm −3 . In compounds 1 and 2 the chelate rings display a chair conformation and their is rans coordination around the central metal cation. In 1 there are two crystallographically independent complex units, which represent different modes of conformational isomerism. In the first one the central copper(II) ion sits at a centre of symmetry, whereas in the second the site symmetry is only C 1. In 2 the site symmetry around the central nickel(II) cation is C 1. All the axial MO bond lengths exhibit axial elongation Extended Hückel calculations suggest that the nature of the axial bonding in the two compounds is essentially different. In the copper(II) complex units it is affected by d-s mixing whereas in the nickel(II) analogue the amount of d-s mixing is almost negligible. The effect of axial bonding is seen also in the geometry of the carboxylate groups. The most noticeable changes occur in the OCO angle of the carboxylate group. The effect of ortho substitution upon the benzoic acid and benzoate anion was investigated at the HF/6–31 + G(d) level of theory. The mean variations are seen in the torsion angle of the carboxylate group.

The electronic structure of ‘linear’ nickel oxides

The geometries, ground states and low-lying excited states of the ‘linear’ nickel oxides NiO, [NiO2]2– and [NiO2]3– have been studied using local density-functional (LDF) calculations within the linear combination of Gaussian-type orbitals framework. The NiO molecule and the [NiO2]2– ion are predicted to have 3Σ– and 3Σg– ground states respectively. The calculated bond lengths and vibrational frequencies are in excellent agreement with experiment. Cellular ligand-field (CLF) analyses of the spectra and magnetic properties have also been performed. The LDF and CLF calculations provide a consistent description of the bonding and suggest that the oxide ions are acting as good σ and π donors in these molecules with both roles enhanced compared to systems with higher co-ordination numbers. The interaction between the dσ orbital and the antibonding σ orbital of predominantly nickel s-orbital character is important in understanding the electronic structure of these systems and its modelling in CLF analyses is described. The description of the bonding in NiO is consistent with that obtained from previous studies. The prediction of a 3Σg– ground state for the [NiO2]2– ion required a reassignment of the spectrum and led to a more satisfactory modelling of the magnetic moment than that given by earlier calculations. The ground state of the [NiO2]3– ion is predicted to be 2Σg+, consistent with its EPR spectrum. The bonding in this low-oxidation-state is weaker than in the nickel(II) oxides and involves considerable contributions from both nickel d and s orbitals.

Formation of a new ligand by addition of methanol to nitrosodicyanomethanide in the nickel(II) coordination sphere

In the system Ni II-ONC(CN) 2 − -pz-CH 3OH−H 2O (pz = pyrazole) a nucleophilic addition of CH 3OH on ONC(CN) 2 − is shown to form a new anionic chelate ligand. The complex [Ni{NO(CN)CC(OCH 3)NH} 2 (pz) 2]·1/2H 2O is produced which according to X-ray crystallography has nitrogen coordinated octahedrally to the central Ni II atom with cis-located pz ligands.

Stereoisomerism in the Nickel(II) Complexes of a Chiral Tridentate Ligand: Solid-State and Solution Study

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereoisomerism in the Nickel(II) Complexes of a Chiral Tridentate Ligand: Solid-State and Solution StudyJean-Pierre Costes, Francoise Dahan, Jose Manuel Dominguez-Vera, Jean-Pierre Laurent, Jose Ruiz, and Jean SotiropoulosCite this: Inorg. Chem. 1994, 33, 18, 3908–3913Publication Date (Print):August 1, 1994Publication History Published online1 May 2002Published inissue 1 August 1994https://doi.org/10.1021/ic00096a014RIGHTS & PERMISSIONSArticle Views171Altmetric-Citations33LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (683 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Extended X-Ray Absorption Fine Structure Spectroscopic Study of Acetone Solutions of Zinc and Lead(II) Ethylxanthate.

EXAFS and vibrational spectra of acetone solutions of zinc and lead(II) ethylxanthate have been recorded in order to correlate structural data with absorption bands in the mid-infrared region. Two ethylxanthate ions are monodentately coordinated to both zinc and lead(II) in acetone solution. Two acetone molecules are weakly coordinated to zinc to complete a tetrahedral configuration round zinc, while no acetone molecules were found in the inner sphere of the lead(II) complex. A band containing a large contribution from the C-S stretching, observed just above 1000 cm(-1) in solid zinc and lead(II) ethylxanthate, where the ethylxanthate ion is bridgingly and bidentately coordinated, respectively, shifts upwards by 20 and 17 cm(-1) in the corresponding zinc and lead(II) complexes, respectively, in acetone solution. An upward shift by about 8 cm(-1) is found in the nickel(II) and arsenic(III) complexes, where the coordination of the ethylxanthate ion remains unchanged but acetone molecules solvate the central ion to complete an octahedral configuration. No shift was found in iron(III) ethylxanthate, where the coordination remains unchanged and no acetone molecules solvate the iron(III) ion. (Less)