Comparative study of IBMK and DIBK as extraction solvents in strongly acidic media: extraction behaviour and kinetic stability of Cu(PCD)(2) in these solvents

The use of di-isobutyl ketone (DIBK) and isobutyl methyl ketone (IBMK) as the solvent for extraction of copper(II) from strongly acidic media (0.01-8M hydrochloric acid) with ammonium l-pyrrolidinecarbodithioate has been studied. In contrast to IBMK, the volume of the DIBK extract remains the same, irrespective of the acidity of the aqueous phase. A certain amount of free acid is transferred into both solvents, and affects the kinetic stability of the chelate extracted; the free acid can be completely removed by washing the extract with water, and partly by filtering it through a dry filter paper. However, the chelate extracted into DIBK exhibits excellent stability without such treatment, since the amount of free acid in DIBK is much smaller than that in IBMK. When DIBK is used, the copper chelate can be quantitatively extracted as long as the extraction is done from acidic media.     

Application of APCD/DIBK extraction system in strongly acidic media: Determination of traces of copper and nickel in titanium metals by extraction-flame atomic-absorption spectrometry

Extraction of nickel in strongly acidic solution (0.01 approximately 8M hydrochloric acid) with ammonium 1-pyrrolidinecarbodithioate (APCD) into di-isobutyl ketone (DIBK) has been studied, and the APCD/DIBK system has been applied to simultaneous extraction and flame atomic-absorption spectrometric determination of trace amounts of copper and nickel in titanium metal. Nickel could be extracted with copper from strongly acidic solution such as up to 5M hydrochloric acid with APCD/DIBK system. The extraction from such a strongly acidic media made it possible to extract nickel with copper, since it did not require the addition of a large amount of the masking agent which prevents the hydrolysis of the matrix titanium and also prevents the extraction of nickel. Thus, they could be extracted directly from the titanium metal sample digested by concentrated hydrochloric acid with a small amount of tetrafluorohydroboric acid. Effect of coexistence of a large amount (at least 0.2 g) of iron on the extraction of both elements could be prevented by keeping most of the matrix titanium as Ti(III). With the method described here, mug/g levels of copper and nickel in titanium metal could be rapidly determined with good precision and accuracy.     

Liquid-liquid extraction of lead(II) with tributyl phosphate

Tributyl phosphate [30% solution in isobutyl methyl ketone (IBMK)] is used for the quantitative extraction of microgram amounts of lead from 3M hydrochloric acid containing lithium chloride (2M) as salting-out agent. It is then stripped from the organic phase with water and determined colorimetrically as its orange-red complex with 4-(2-pyridylazo)resorcinol at 520 nm. TBP alone cannot quantitatively extract lead in the absence of salting-out agents. The IBMK used as diluent does not extract lead under the conditions used. The period of equilibration needed is 5 min. Lead can be extracted in the presence of up to 100 times as much of certain other ions. The method is found to be applicable to analysis of gun-metal.     

半胱氨酸铜络合物的生成及其结构的研究

本文研究了在不同pH值下,半胱氨酸与CuCl_2络合生成的三种不同的络合物。在酸性溶液中,半胱氨酸与CuCl_2通过络合反应、自氧化还原反应,最后生成带氯桥的络合物[Cu_2(Ⅰ)Cl_2(cysH_2)]的白色粉末,(cysH_2为半胱氨酸)。在碱性溶液中,若反应在空气中进行,半胱氨酸与CuCl_2经氧化还原反应,结果生成天蓝色络合物(Cu_2(Ⅱ)(cyss)_2],(cyss~(2-)为胱氨酸根);若反应在绝氧条件下进行,它们则先络合,然后二聚成黑色络合物[Cu_2(Ⅱ)(cys)_2·6H_2O)。根据化学分析以及IR和ESR谱的研究,推测了这三种络合物的可能结构。     

Simultaneous determination of heavy metals in waters by inductively-coupled plasma atomic emission spectrometry after extraction into diisobutyl ketone

Nebulization of more than thirty aliphatic and aromatic liquids into a low power (<1.6 kW) argon inductively-coupled plasma (i.c.p.) was evaluated. Diisobutyl ketone (DIBK) was best owing to the ease of its introduction into the i.c.p. and low aqueous solubility. Dichloro-8-quinolinol, hexamethyleneammonium hexamethylenedithiocarbamate and ammonium pyrrolidinedithiocarbamate were tested for extraction ; the last was preferred as chelating reagent because it formed complexes with Cd, Pb, Zn, Fe, Cu, Ni, Mo and V at pH 2.4. These metals at μg l^-1 levels in river and sea water were extracted into DIBK and determined simultaneously by i.c.p. atomic emission spectrometry. The optimum observation height for the DIBK extract was higher than that for an aqueous solution.     

Extraction of copper(II) with the APCD/DIBK system from concentrated hydrochloric and nitric acid media: estimation of true limit of acidity for the extraction

The extraction of copper(II) from strongly acidic solution (0.01-8M hydrochloric and 0.01-5M nitric acid) with ammonium 1-pyrrolidinecarbodithioate in di-isobutyl ketone has been studied. Compared with the hydrochloric acid system, a considerably larger amount of the reagent is needed for complete extraction of copper chelate from nitric acid solution as the extract is more unstable in the nitric acid system. The decomposition of copper chelates extracted from nitric acid is based on the oxidation of the reagent and the chelate; the spectral change of the extract from nitric acid suggests that the copper(II) chelate is initially oxidized to copper(II) and then decomposes. The upper limit of the acidity of both acids from which the copper chelate can be quantitatively extracted strongly depends on the reagent concentration; the limit with 8 x 10(-2)M APCD (500-fold reagent: metal molar ratio) was taken as 8 and 4M for hydrochloric and nitric acid, respectively.     

Electrospray ionization tandem mass spectrometric study of salt cluster ions: part 2--salts of polyatomic acid groups and of multivalent metals

Salt cluster ions formed from 0.05 M solutions of CaCl(2), CuCl(2) and Na(A)B (where A = 1 or 2 and B = CO(3)(2-), HCO(3)(-), H(2)PO(4)(-) and HPO(4)(2-)) were studied by electrospray ionization tandem mass spectrometry. The effects on salt cluster ions of droplet pH and of redox reactions induced by electrospray provide information on the electrospray process. CaCl(2) solution yielded salt cluster ions of the form (CaCl(2))(n)(CaCl)(x)(x+) and (CaCl(2))(n)(Cl)(y)(y-), where x, y = 1-3, in positive- and negative-ion modes, respectively. Upon collision induced dissociation (CID), singly charged CaCl(2) cluster ions fragmented, doubly charged cluster ions generated either singly or both singly and doubly charged fragment ions, depending on the cluster mass, and triply charged clusters fragmented predominantly by the loss of charged species. CuCl(2) solution yielded nine series of cluster ions of the form (CuCl(2))(n)(CuCl)(m) plus Cu(+), CuCl(+), or Cl(-). CuCl, the reductive product of CuCl(2), was observed as a neutral component of positively and negatively charged cluster ions. Free electrons were formed in a visible discharge that bridged the gap between the electrospray capillary and the sampling cone brought about the reduction of Cu(2+) to Cu(+). Upon CID, these cluster ions fragmented to lose CuCl(2), CuCl, Cl, and Cl(2). Na(2)CO(3) and NaHCO(3) solutions yielded cluster ions of the form (Na(2)CO(3))(n) plus Na(+) or NaCO(3)(-). Small numbers of NaHCO(3) molecules were found in some cluster ions obtained with the NaHCO(3) solution. For both Na(2)HPO(4) and NaH(2)PO(4) solutions, ions of the form (Na(2)HPO(4))(h), (NaH(2)PO(4))(i), (Na(3)PO(4))(j), (NaPO(3))(k) plus Na(+), PO(3)(-) or H(2)PO(4)(-) were observed. In addition, ions having one or two phosphoric acid (H(3)PO(4)) molecules were observed from the NaH(2)PO(4) solution while ions containing one sodium hydroxide (NaOH) molecule were observed from the Na(2)HPO(4) solution. The cluster ions observed from these four salts of polyatomic acid groups indicate that changes in pH occur in both directions during the electrospray process principally by solvent evaporation; the pH value of the acidic solution became lower and that of the basic solution higher.     

Extraction-spectrophotometric determination of niobium with dibenzo-18-crown-6 and thiocyanate

A method is described for the direct spectrophotometric determination of micro-amounts of niobium by extraction into a benzene solution of dibenzo-18-crown-6 (L) from 3M hydrochloric acid containing potassium thiocyanate. The molar absorptivity of the extracted complex is 3.85 +/- 0.03 x 10(4) 1.mole(-1).cm(-1) (relative standard deviation 0.8%). Co-ordinatively unsaturated complexes of the type [NbO(SCN)(3)](2)L and NbO(SCN)(3)L are extracted, along with ion-pairs, especially when small amounts of L are used for extraction. The ion-pair complex [NbOCl(2)(SCN)(3)][(LK)(2)] seems to be the main species formed in the organic phase.     

Charge-transfer photochemistry of the ternary complex (dithio-diseleno-carbamato)copper(II)

Photolysis of the ternary system consisting of diethyldithiocarbamate (Et2dtc), diethyldiselenocarbamate (Et2dsc) and copper(II) (1:1:1) has been studied in isobutylmethylketone (IBMK), toluene, chloromethane and chloromethane/ROH solutions (chloromethane = CCl4, CHCl3 or CH2Cl2 and ROH = EtOH or i-PrOH). The results obtained by EPR techniques and UV-Vis data indicate that a homolytic Cu-S bond cleavage involving the dithiocarbamate (dtc) ligand appears as the primary photo-process in Cu(Et2dtc)(Et2dsc) photolysis. Further conversion of the primary photoproduct Cu(I)(Et2dsc) is discussed in terms of a specific interaction with the solvent. In chloromethanes and chloromethane/ROH Cu(I)(Et2dsc) is oxidised by the solvent to give the corresponding paramagnetic mixed-ligand Cu(II)(Et2dsc)Cl complex and/or its chloride-bridged and EPR silent dimer Cu2(Et2dsc)2Cl2. The formation of the monomeric species occurs through a co-ordination of the alcohol molecule in the xy plane of the complex. Because of its co-ordination inertness, toluene poorly stabilises the primary photoproduct Cu(I)(Et2dsc), thus providing an effective primary recombination process and lower efficiency of Cu(Et2dtc)(Et2dsc) photolysis. The formation of the bis-solvated mixed-ligand complex Cu(II)(Et2dsc)+ in IBMK is also discussed.     

Copper(I) chloride initiated decomposition of 7-phosphanorbornadiene. Evidence for a solvent-assisted catalytic mechanism

Density functional theory is used to explore the mechanism of the copper(I)-chloride-catalyzed decomposition of W(CO)(5)-complexed 7-phosphanorbornadiene and the subsequent olefin trapping of the terminal phosphinidene complex. CuCl lowers the activation barrier by interacting directly with the breaking P-C bond. Contrary to the prevailing notion that a free terminal phosphinidene complex (W(CO)(5)=PR) is generated in the CuCl-catalyzed cheletropic elimination of the 7-phosphanorbornadiene-W(CO)(5) complex, the present mechanism suggests that CuCl is attached to the terminal phosphinidene. Furthermore, a "chloride shuttle" takes place where the chloride first migrates to the phosphorus center and then is returned back to the copper center by the incoming olefin in an S(N)2 reaction step. When the substituent on phosphorus is a phenyl group (R = Ph), the uncatalyzed reaction has an activation barrier of 17.9 kcal/mol, which is reduced by 10.9 kcal/mol on including the CuCl catalyst. The CuCl-catalyzed decomposition of 7-phosphanorbornadiene followed by olefin trapping of the terminal phosphinidene complex has a close parallel with the Cu(I)-catalyzed cyclopropanation reaction of diazoalkane. In both catalyzed reactions, copper(I) is coordinated to the phosphinidene/carbene as a Lewis acid, while a Lewis base is displaced from the phosphorus/carbon center as the olefin is added.     

Mono- and dinuclear complexes of chiral tri- and tetradentate Schiff-base ligands derived from 1,1'-binaphthyl-2,2'-diamine

The synthesis and characterization of the bis(bidentate) Schiff-base ligand [(R)-2] formed by the condensation reaction of (R)-1,1'-binaphthyl-2,2'-diamine [(R)-BINAM] with pyridine-2-carboxaldehyde is presented. The coordination chemistry of (R)-2 with Ni(ClO(4))(2).6H(2)O, Co(ClO(4))(2).6H(2)O, CuCl(2), and CuSO(4) has been investigated. Reaction of (R)-2 with the first two metal salts leads to complexes of the type [M((R)-4)(2)](ClO(4))(2) (M = Ni(II), Co(II)), where (R)-4 is a tridentate ligand resulting from the hydrolytic cleavage of one of the pyridyl groups from (R)-2. Both complexes were characterized by X-ray crystallography, which showed that the Lambda absolute configuration of the metal center is favored in both cases. (1)H NMR spectroscopy suggests that the high diastereoselectivity of Lambda-[Co((R)-4)(2)](ClO(4))(2) is maintained in solution. The reaction of (R)-2 with CuCl(2) leads to the dinuclear complex [Cu(2)((R)-2)Cl(4)], which has a [Cu(2)(mu(2)-Cl(2))] core. The reaction of CuSO(4) with (R)-2 gives a dimeric complex, [Cu((R)-4)SO(4)](2), which features a [Cu(2)(mu(2)-(SO(4))(2))] core. This complex can be prepared directly by the reaction of (R)-BINAM with pyridine-2-carboxaldehyde and CuSO(4). The use of rac-BINAM in this synthetic procedure leads to the heterochiral dimer [Cu(2)((R)-4)((S)-4)(SO(4))(2)]; that is, the ligands undergo a self-sorting (self/nonself discrimination) process based on chirality. The reaction of rac-BINAM, pyridine-2-carboxaldehyde, and Co(ClO(4))(2).6H(2)O proceeds via a homochiral self-sorting pathway to produce a racemic mixture of [Co((R)-4)(2)](2+) and [Co((S)-4)(2)](2+). The variable-temperature magnetic susceptibilities of the bimetallic complexes [Cu(2)((R)-2)Cl(4)], [Cu((R)-4)(mu(2)-SO(4))](2), and [Cu(2)((R)-4)((S)-4)(mu(2)-SO(4))(2)] all show weak antiferromagnetic coupling with J = -1.0, -0.40, and -0.67 cm(-)(1), respectively.     

Effect of acidity on the extraction and kinetic stability of the copper(II)/APCD/IBMK system in strongly acidic media

The extraction of copper(II) from strongly acidic solution (0.01-8M hydrochloric acid) with ammonium 1-pyrrolidinecarbodithioate in isobutyl methyl ketone has been investigated. The shaking time needed for quantitative extraction decreases as the acidity is increased. The effect of the mutual solubility of the organic solvent and the aqueous phase is significant when the acidity of the aqueous phase is increased. The acidity of the aqueous phase mainly affects the kinetic stability of the chelate during the shaking period, rather than the decomposition of the chelating agent. The kinetic stability of the chelate apparently depends on the mole ratio of reagent to copper, the half-lives for the chelate extracted from 4M hydrochloric acid being 29.0, 40.0 and 85.0 min for reagent: metal mole ratios of 10, 100 and 1000, respectively.     

Unsupported gold(I)-copper(I) interactions through eta1 Au-[Au(C6F5)2]- coordination to Cu+ Lewis acid sites

The reaction of the complex [Au2Ag2(C6F5)4)N[triple bond]CCH3)2]n (1) with 1 equiv of CuCl in the presence of 1 equiv of pyrimidine ligand leads to the formation of the heteronuclear Au(I)-Cu(I) organometallic polymer [Cu{Au(C6F5)2}(N[triple bond]CCH3)(mu2-C4H4N2)]n (2) through a transmetalation reaction. Complex 2 displays unprecedented unsupported Au(I)...Cu(I) interactions of [Au(C6F5)2]- units with the acid Cu(I) sites in a [Cu(N[triple bond]CCH3)(mu2-pyrimidine)]n+(n) polymeric chain. Complex 2 has a rich photophysics in solution and in the solid state.     

Two enantiomers of [Cu(3)(mnt)(3)](3-) as ligands to Cu(i) or Ag(i) in building [Cu(6)M(2)(mnt)(6)](4-) complexes (M = Cu or Ag) with the reversal of the reaction by X(-) (X = Cl, Br)

Two enantiomers of [Bu(4)N](3)[Cu(3)(mnt)(3)] () formed by Na(2)(mnt) (mnt = maleonitriledithiolate, [S(2)C(2)(CN)(2)](2-)) and CuCl in a 1 : 1 molar ratio react further with MCl (M = Cu or Ag) involving both the enantiomers of to produce the larger complex, [Bu(4)N](4)[Cu(6)M(2)(mnt)(6)] (M = Cu (2), Ag (3)) from which the capped Cu(+) or Ag(+) ion can readily be removed by Bu(4)NX (X = Cl, Br), reverting or back to . Such reversal does not work with non-coordinating anions like BF(4)(-), ClO(4)(-) and PF(6)(-).     

A Study of Сu(II) Complexes with Pyruvic Acid Nicotinoyl and Isonicotinoyl Hydrazones by EPR and X-ray Absorption Spectroscopy

The composition and structure of the Cu²⁺ coordination cores in the previously synthesized [CuCl(HNPv)] · H₂O, [CuCl(HIPv)] · H₂O, [Cu(AOc)(HNPv)], [Cu(AOc)(HIPv)], [Cu(NO₃)(HNPv)], and [Cu(NO₃)(HIPv)] complexes, where HNPv and HIPv pyruvic acid nicotinoyl and isonicotinoyl hydrazones, respectively, have been determined. The binuclear complex [Cu₂(HNPv)₂(H₂O)2(μ-Cl)] has been synthesized for the first time and characterized by elemental analysis and IR, EPR, and EXAFS spectroscopy. Its dimeric structure has been proved by magnetic susceptibility measurement and EPR.     

Synthesis and structural studies of binuclear platinum(II) complexes with a novel phosphorus-nitrogen-phosphorus ligand

The new pyridinediphosphinite ligand PONOP (1) was synthesized in one step from 2,6-pyridinedimethanol and diphenylchlorophosphane. Reaction of 1 with PtCl(2)(PhCN)(2) led to the neutral homobimetallic complex [Pt(2)Cl(4)(PONOP)(2)] (2), where the benzonitriles have been substituted by the phosphorus atoms of 1. The X-ray structure of 2 revealed a metallamacrocycle where the pyridines remained free. Addition of 2 equiv of [Cu(MeCN)(4)](BF(4)) to 2 led to CuCl and to the binuclear dicationic complex [Pt(2)Cl(2)(PONOP)(2)](BF(4))(2) (3), where chloro ligands have been substituted by pyridine groups. Conversely, reaction of 3 with chloride anions gave back complex 2. Solid-state (X-ray) and solution (NMR) studies indicated that after the transformation of 2 into 3, the platinum centers were brought much closer and the pyridinediphosphinite ligand was stiffened. The methylene NMR protons of 3 were strongly deshielded, and the corresponding proton-phosphorus coupling constants followed a Karplus-type relationship.     

Determination of molybdenum by extraction of its thiocyanate into ethyl methyl ketone

A simple, sensitive and selective spectrophotometric method for determination of molybdenum is described. A solution containing 100 mug of Mo in 2.5M hydrochloric acid is treated with ascorbic acid and ammonium thiocyanate and after standing for 8 min is shaken with an equal volume of ethyl methyl ketone for 30 sec. The absorbance of the complex is measured at 465 nm against a reagent blank. The complex is stable for 1 hour. There is no interference from Re(VII), SO(2-)(4), Cl(-), CH(3)COO(-), PO(3-)(4), NO(-)(3), C(2)O(2-)(4), citrate or tartrate, and at least 5 mg of U(VI), 10 mg of Cr(III, VI), Th, or Ni, and 20 mg of W(VI) Can be tolerated. Vanadium(V) interferes at the 500 mug level, and fluoride slightly decreases the absorbance.     

Copper complexes of mono- and ditopic [(methylthio)methyl]borates: missing links and linked systems en route to copper enzyme models

TMEDA-free (TMEDA: tetramethylethylenediamine) LiCH(2)SMe is a suitable reagent for the selective introduction of (methylthio)methyl groups into PhBBr(2) and its p-silylated derivative Me(3)Si--C(6)H(4)--BBr(2). The resulting compounds, R*--C(6)H(4)--B(Br)(CH(2)SMe) (R*=H: 2; R*=SiMe(3): 7) and PhB(CH(2)SMe)(2) (3), form cyclic dimers through B--S adduct bonds in solution and in the solid state. Compounds 2 and 3 have successfully been used for preparing the (N(2)S) scorpionate [PhBpz(2)(CH(2)SMe)](-) ([5](-)) (pz: pyrazol-1-yl) and the (NS(2)) scorpionate [PhBpz(CH(2)SMe)(2)](-), respectively. Compound 7 proved to be an excellent building block for the heteroditopic poly(pyrazol-1-yl)borate p-[pz(3)B--C(6)H(4)--Bpz(2)(CH(2)SMe)](2-) ([10](2-)) that mimics the two ligation sites of the copper enzymes peptidylglycine alpha-hydroxylating monooxygenase and dopamine beta-monooxygenase. Treatment of the monotopic tripod [5](-) with CuCl and CuBr(2) results in the formation of complexes K[Cu(5)(2)] and [Cu(5)(2)]. An X-ray crystallography study of K[Cu(5)(2)] revealed a tetrahedral (N(2)S(2)) coordination environment for the Cu(I) ion, whereas the Cu(II) ion of [Cu(5)(2)] possesses a square-pyramidal (N(4)S) ligand sphere (S-atom in the axial position). The remarkable redox properties of K[Cu(5)(2)] and [Cu(5)(2)] have been assessed by cyclic voltammetry and quantum chemical calculations. The reaction of K[Cu(5)(2)] with dry air leads to the Cu(II) species [Cu(5)(2)] and to a tetranuclear Cu(II) complex featuring [PhB(O)pz(2)](2-) ligands. Addition of CuCl to K(2)[10] gives the complex K(3)[Cu(10)(2)] containing two ligand molecules per Cu(I) center. The Cu(I) ion binds to both heteroscorpionate moieties and thereby establishes a coordination environment similar to that of the Cu(I) ion in K[Cu(5)(2)].     

Spectrophotometric determination of tungsten with thiocyanate

The yellow W(V) thiocyanate complex is formed by shaking sodium tungstate solution in 0.2-0.8M potassium thiocyanate and 4-5M hydrochloric acid, with mercury. It is extracted with 2% tribenzylamine solution in chloroform and measured at 410 nm. U, Ti, V, Cr, Fe, Co, Ni, Mn, Al, Pb, Sn, Bi, Pd, Sb and Cu do not interfere. Pt and Mo in amount equal to that of tungsten give errors of up to 0.4 and 2% respectively. The sensitivity is 0.013 mug ml and Beer's law is obeyed up to 24 mug ml .     

5-异烟酰胺基异酞酸与含氮配体构筑的两个铜配合物：水热合成、晶体结构和磁性质研究

由水热法合成了2个铜配合物[Cu(INAIP)(bbi)]·5H₂O (1)和[Cu(INAIP)(phen)(H₂O)]·H₂O (2)(H₂INAIP=5-异烟酰胺基异酞酸,bbi=1,4-二咪唑基丁烷,phen=1,10-邻菲咯啉),并用元素分析、IR及X-射线单晶衍射等对其进行了表征。晶体结构分析结果表明：配合物1和2都属于单斜晶系,C2/c空间群。配合物1是由1,4-二咪唑基丁烷连接[Cu(INAIP)]一维链形成的二维双层结构,而配合物2是通过π-π堆积作用将[Cu(INAIP)]一维无限链延伸为二维结构,这2个化合物最终均被氢键拓展成三维超分子结构。在1.8~300 K温度范围内测试了配合物1和2的变温磁化率,结果表明配合物1中由羧基桥联的双核铜之间存在弱的反铁磁相互作用,而配合物2表现为顺磁性。