Geoffrey Lawrance

University of Newcastle Australia · Department of Chemistry

Recrystallization of [PdCl2([9]aneS(2)O)] ([9]aneS(2)O = 1-oxa-4,7-dithiacyclononane), 1, and [PtCl2([9]aneS(2)O)], 2, by diffusion of Et2O vapor into solutions of the complexes in MeNO2 yielded three phases of 1 and two phases of 2. The known phase of 1, herein designated alpha-1, was obtained under ambient conditions. A second phase, designated b...

Piperazine (PZ) is widely recognised as a promising solvent for post combustion capture (PCC) of carbon dioxide (CO2). In view of the highly conflicting data describing the kinetic reactions of CO2(aq) in piperazine solutions, the present study focuses on the identification of the chemical mechanism, specifically the kinetic pathways for CO2(aq) in...

The present study reports (a) the determination of both the kinetic rate constants and equilibrium constants for the reaction of CO2(aq) with sterically-hindered amines and (b) an attempt to elucidate a fundamental chemical understanding of the relationship between the amine structure and chemical properties of the amine that are relevant for post-...

Carbamate formation is one of the major chemical reactions that can occur in solution in the capture of CO2 by amine-based solvents, and carbamate formation makes a significant enthalpy contribution to the absorption-desorption of CO2 that occurs in the absorber/stripper columns of the PCC process. Consequently, the formation of carbamates of selec...

The leading process for the post combustion capture (PCC) of CO2 from coal-fired power stations and hence reduction in greenhouse gases involves capture by aqueous amine solutions. Of the reactions that occur in solution, which include CO2 hydration, de-protonation of carbonic acid, amine protonation and carbamate formation, the protonation of the...

The kinetics of the fast reversible carbamate formation reaction of CO(2)(aq) with a series of substituted cyclic secondary amines as well as the noncyclic secondary amine diethanolamine (DEA) has been investigated using the stopped-flow spectrophotometric technique at 25.0 °C. The kinetics of the slow parallel reversible reaction between HCO(3)(-)...

Metal-directed macrocyclisation reactions of [Cu(diamine)2] (diamine = ethane-, propane-, and trans-cyclohexane-1,2-diamine, and propane-1,3-diamine) and [Co(ethane-1,2-diamine)3] with formaldehyde and a nitroalkane carbon acid were examined for the first time in an ionic liquid solvent (1-butyl-3-methylimidazolium tetrafluoroborate), and compared...

The temperature dependence of the reversible reaction between CO(2)(aq) and monoethanolamine (MEA) has been investigated using stopped-flow spectrophotometry by following the pH changes during the reactions with colored acid-base indicators. Multivariate global analysis of both the forward and backward kinetic measurements for the reaction of CO(2)...

Mixed donor ligands are extremely common and are linear, branched, or cyclic molecules that contain at least two different donor groups capable of chelation to metal ions by those groups as polydentate ligands. The most common donor atoms met are N, O, S, and P, although other donors such as group 14 elements (including C) are known. Whereas mixed...

The potentially tridentate N,N′,O-donor N-trans-(2′-hydroxycyclohexyl)-2-aminomethylpyridine (1) forms ML2 complexes with M(II) = Cu, Ni, and Zn. X-ray crystal structures of the isostructural Ni(II) and Zn(II) complexes confirm bis-tridentate coordination in significantly distorted octahedral geometries as the all-cis facial isomer. Structural comp...

The kinetics of the interactions of aqueous ammonia with aqueous carbon dioxide/carbonate species has been investigated using stopped-flow techniques by monitoring the pH changes via indicators. The reactions include the reversible formation of ammonium carbamate/carbamic acid. A complete reaction mechanism has been established, and the temperature...

The ligand 3,4-diamino-5-methyl-4H-1,2,4-triazole (DAMT) and its trinuclear cadmium complex [Cd3(DAMT)2(DAMTH)2Cl8] have been prepared and identified by elemental analyses, infrared, Raman, 1H and 13C NMR spectroscopy, and single crystal X-ray diffraction. The protonation equilibria of the ligand have been studied by pH-potentiometry, with pK 1 13....

An amperometric glucose biosensor was fabricated by entrapment of glucose oxidase in a composite matrix of silica sol-gel and polyvinyl alcohol physically layered on top of a Prussian blue-modified Pt electrode. This biosensor functions through the detection of hydrogen peroxide produced by the glucose oxidase-catalyzed oxidation of glucose at -0.0...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Oxidation of Mn2+aq by HSO5- to manganese(IV) in the presence of molybdate ion in acetate buffer involves the formation of the soluble heteropolymolybdate anion [MnMo9O32]6-. This was crystallized as K6[MnMo9O32].6H2O from the reaction mixture in the rhombohedra1 space group R32, a 15.569(1), c 12.432(1) Å , and the structure was determined by X-ra...

Reaction of 2,6-bis(methoxycarbonyl)pyridine with two equivalents of a β-amino alcohol yields pyridine-2,6-diamides C6H3N(CONH–CR1R2–CHR3–OH)2 [(1) R1 = R2 = R3 = H; (2) R1 = R2 = H, R3 = CH3; (3) R1 = CH3, R2 = R3 = H; (4) R1 = C2H5, R2 = R3 = H; (5) R1 = C6H5CH2, R2 = R3 = H; (6) R1 = O2NC6H4CH(OH), R2 = R3 = H; (7) R1 = R2 = CH3, R3=H] incorpora...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The pendant-arm macrocycles 12-methyl-1,4,7,10-tetraazacyclotridecane-12-amine (L3), 6-methyl-1,4,8,11-tetraazacyclotetradecane-6-amine (L4) and 10-methyl-1,4,8,12-tetraazacyclopentadecane-10-amine (L5) react readily in methanol with chromium(II) ion, followed by dilution with aqueous hydrochloric acid and chromatography, to yield cis- and or trans...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The first example of a heteropolyoxomolybdate containing palladium(IV) was isolated and characterized by X-ray crystallography. The palladium(IV) hexamolybdate, K0.75Na3.75[PdMo6O24H3.5]·17H2O, was isolated from an aqueous solution at pH 4.5 in the space group P\bar{1}, a 10.790(2), b 12.244(3), c 14.086(3) Å, α 113.77(1), β 90.41(1),γ 107.86(1)°,...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Combined kinetic and equilibrium studies of the complexation of the ligand N,N'-bis[2-(2-pyridyl)methyl]pyridine-2,6-dicarboxamide with copper(ii) and nickel(ii), examined conjointly employing advanced chemometric methods, provides elucidation of speciation and formation pathways in solution for complexes such as M2L2 and M2L3 helicates, respective...

Half-Title PageWiley Series PageTitle PageCopyright PageTable of ContentsPrefacePreamble

Key Concepts in Coordination ChemistryA Who's Who of Metal IonsMetals in MoleculesThe Road AheadConcept KeysFurther Reading

Life's a Metal IonMetalloproteins and MetalloenzymesDoing What Comes Unnaturally – Synthetic BiomoleculesA Laboratory-free Approach – In Silico PredictionConcept KeysFurther Reading

The leaching of gold, silver and base metals from a sulfidic gold ore in the presence of an oxidant (peroxomonosulfate (HSO5−) or iron(III)) and leaching agent (thiourea, chloride, bromide or iodide) is compared in 1-butyl-3-methylimidazolium hydrogen sulfate (bmimHSO4) and chloride (bmimCl) ionic liquids, as well as in aqueous saturated K2SO4 as t...

Electrospray mass spectrometry analyzes ions which have been generated in the gas-phase from electrically charged droplets obtained by nebulizing a solution. While the generation of an aerosol by electrospray was published by Zeleny in 1917, it was not until approximately some seven decades later when it was successfully interfaced to a mass spectr...

The direct electron transfer of glucose oxidase (GOx) immobilized on a large-pore mesoporous silica KIT-6 matrix fixed to a screen-printed electrode (SPE) and its application as a disposable biosensor were studied. KIT-6 plays a vital role in this method through immobilizing GOx and facilitating the electron communication between the active centers...

The kinetics of Mn2O3 digestion in various H2SO4 solutions (0.5-2.0 M) and at various temperatures (ambient to 80 °C) to form solid gamma-MnO2 and soluble Mn(II) have been examined using X-ray diffraction. Using a modified first-order Avrami expression to describe digestion kinetics, rate constants in the range 0.02-0.98 h-1 were found for Mn2O3 di...

magnified image Symmetrically‐armed molecules based on a 2,6‐diamidopyridine core, 2,6‐bis[ N ‐(1′‐piperidinylethyl)carbamyl]pyridine ( 1 ), 2,6‐bis[ N ‐(1′‐piperazinylethyl)carbamyl]pyridine ( 2 ), 2,6‐bis[ N ‐2′‐(5′′‐nitropyridine)‐1′‐azapropyl)carbamyl]pyridine ( 3 ), 2,6‐bis[ N ‐(3′‐hydroxypropyl)carbamyl]pyridine ( 4 ), 2,6‐bis[ N ‐(5′‐hydroxy...

Post combustion capture, PCC, of CO2 from the flue gas stream of coal fired power stations is an attractive proposition for the reduction of CO2 output into the atmosphere. PCC based on reversible absorption by aqueous amine solution is probably the most advanced technology. Thus the investigation of the chemistry of CO2 absorption by such solution...

Complexation of the symmetric cyclic diamine piperazine (1,4-diazacyclohexane) has been examined in dry dimethyl formamide by spectrophotometric titrations (with Cu2+, Ni2+) to define formation constants, and by stopped-flow kinetics to define the complexation rates and reaction pathway. Initial formation of a rarely observed eta(1)-piperazine inte...

A simple, polishable and renewable DNA biosensor was fabricated based on a zirconia modified carbon paste electrode. Zirconia was mixed with graphite powder and paraffin wax to produce the paste for the electrode, and response-optimized at 56% graphite powder, 19% ZrO(2) and 25% paraffin wax. An oligonucleotide probe with a terminal 5'-phosphate gr...

Interaction between tetramethylcucurbit[6]uril and 3-amino-5-phenylpyrazole hydrochloride in aqueous solution has been investigated by using 1H NMR spectroscopy, electronic absorption spectroscopy and fluorescence spectroscopy, as well as by a single crystal X-ray diffraction determination. The 1H NMR spectra analysis established a basic interactio...

The interaction between cucurbit[8]uril (Q[8]) and a series of symmetric viologen derivatives having aliphatic substituents of variable length [N,N′-dialkyl-4,4′-bipyridinium dianions; alkyl=CH3(CH2) n –, n=0 (MV2+), 1 (EV2+), 2 (PV2+), 3 (BV2+), 4 (FV2+), 5 (HV2+) or 6 (SV2+); BPY2+=diprotonated 4,4-bipyridine], determined by 1H NMR and electronic...

Uncharged complexes, formulated as trimeric metallocycles of type [M3(L(1))3(Py)6] (where M = cobalt(II), nickel(II) and zinc(II) and L(1) is the doubly deprotonated form of a 1,4-phenylene linked bis-beta-diketone ligand of type 1,4-bis(RC(O)CH2C(O))C6H4 (R = t-Bu)) have been synthesised, adding to related, previously reported complexes of these m...

I am ligand: A pentadentate bispidine ligand with two tertiary amine and three pyridine donors stabilizes the uncommon intermediate-spin electronic configuration of CoIII (S=1; see picture: C gray, N blue, O red, Co violet). Dissociation of the monodentate coligand yields a catalytically active pentacoordinate complex.

In a series of simple synthetic manipulations the active component of the aphrodisiac Spanish fly has resulted in the generation of a new family of room-temperature ionic liquids (RTILs). These RTILs are synthesized in high yield from readily attainable starting materials and can be generated in either meso or chiral forms dependant on the starting...

A simple, disposable, and inexpensive electrochemical DNA biosensor based on a zirconia (ZrO(2)) modified thin film screen-printed electrode (ZrO(2)/SPE) has been developed. Short DNA sequences ( 21 monomer units) from the Escherichia coli pathogen, modified with a phosphate group at the 5' end, were attached to the surface of the electrode through...

The application of 1-butyl-3-methyl-imidazolium hydrogen sulphate (bmim+(HSO4−)) ionic liquid and close analogues is described as a solvent medium (either as a neat liquid and or as aqueous mixtures) for the leaching of gold, silver, copper and base metals from sulphidic ores using thiourea (mainly) in the presence of iron(III) as oxidant. Initiall...

Cations derived by protonation of the ligand title compound (L1) have been structurally characterized in their di- and tetra- protonated forms in the salts [H2L1][ClO4]2·2H2O and [H4L1][ZnCl4]2·4H2O. In both structures, one half of the formula unit comprises the asymmetric unit of the structure, the macrocycle being centrosymmetric, with the two ma...

Neutral dimeric metallocyclic complexes of type [M(2)(L(1))(2)B(n)] (where M = cobalt(II), nickel(II) and zinc(II), L(1) is the doubly deprotonated form of a 1,3-aryl linked bis-beta-diketone ligand of type 1,3-bis(RC(O)CH(2)C(O))C(6)H(4) (R=Me, n-Pr, t-Bu) and B is pyridine (Py) or 4-ethylpyridine (EtPy)) have been synthesised, adding to similar c...

Ligand-protonation constants and complexation kinetics of differently protonated forms of 10-methyl-1,4,8,12-tetraazacyclopentadecan-10-amine, 1,4,8,12-tetraazacyclopentadecane, and 1,4,8,12-tetraazacyclopentadecan-10-carboxylic acid with Cu(II) and Ni(II) in aqueous solution have been determined. These results are combined with a wide range of pub...

The facility of aminoalcohol ligand synthesis via ring opening of cyclohexene oxide with polyamines including a piperazine ring is illustrated here with the syntheses and characterization of (2′-hydroxycyclohexyl)piperazine (1), bis(2′-hydroxycyclohexyl)-piperazine (2), 4-{(2″-hydroxycyclohexyl)-2′-aminoethyl)}piperazine (3), 1-(2″-hydroxycyclohexy...

Interaction between tetramethylcucurbit[6]uril (TMeQ[6], host) with hydrochloride salts of 2-phenylpridine (G1), 2-benzylpyridine (G2), and 4-benzylpyridine (G3) (guests) have been investigated by using 1H NMR spectroscopy and electronic absorption spectroscopy and theoretical calculations. The 1H NMR spectra analysis established an interaction mod...

Solubility determinations of gypsum were conducted on simulated process liquors containing 0–72 g/kg solution Mn2+ (as sulfate) and 0–72 g/kg solution H2SO4 from 30 °C to 105 °C. At temperatures ≤ 80 °C gypsum solubility was shown to increase with increasing H2SO4 concentration and temperature in accord with the dissociation equilibrium of the bisu...

An electrochemical quartz crystal microbalance (EQCM) has been used to study the effects of electrolyte composition (MnSO4 and H2SO4 concentrations) and anodic current density on the electrodeposition of manganese dioxide. The EQCM, in tandem with the electrode voltage during deposition, has been used to characterize features of the deposition mech...

Transition metal complexes with 2,4-substituted tetradentate, 2,3,4- and 2,4,7-substituted pentadentate, and 2,3,4,7-substituted hexadentate bispidine ligands (bispidine = 3,7-diazabicyclo[3.3.1]nonane) with two tertiary amine and two, three, or four pyridine donors are relatively stable (10 < log K(CuL) < 18). Interestingly, the two isomeric penta...

Pentaammine(trifluoromethanesulfonato-O)chromium(III) Trifluoromethanesulfonate, [Cr(NH3)5(OSO2CF3)](CF3SO3)2 cis-Bis(1,2-ethanediamine)bis(trifluoromethanesulfonato-O)-chromium(III)Trifluoromethanesulfonate, cis-[Cr(en)2(OSO2 CF3)2](CF3SO3

Pentammine(trifluoromethanesulfonato)cobalt(III)Trifluoromethanesulfonate,[Co(NH3)5OSO2CF3](CF3SO3)2 cis-Bis(1,2-ethylenediamine)di(trifluoromethanesulfonato)cobalt(III)Trifluoromethanesulfonate,cis-[Co(en)2(OSO2CF3)2](CF3SO3) cis-Tris(trifluoromethanesulfonato)[N-(2-aminoethyl)-1,2-ethaneduamine]cobalt(III),Co(dien)(OSO2CF3)3

Reaction of [Mo(CO)3(3-azahexane-1,6-diamine)] with formaldehyde and the carbon acid nitroethane leads to cyclisation involving one terminal amine and either the internal secondary amine (minor product) or the other terminal primary amine (major product), with zinc/acid reduction yielding new cyclic tetraamines, also characterised as their cobalt(I...

Based on the 10-methyl-1,4,8,12-tetraazacyclopentadecane-10-amine (1) parent, macrocycles 10-benzylamine-10-methyl-1,4,8,12-tetraazacyclopentadecane (2), 10-(2′-pyridinylmethanamino)-10-methyl-1,4,8,12- tetraazacyclopentadecane (3) and 5-(hydroxymethyl)-5′-(10″-methyl- 1″,4″,8″,12″-tetraazacyclopentadecane-10″-amino) -(2,2′-dipyridine) (4), as well...

Mixed donor ligands are extremely common and are linear, branched, or cyclic molecules that contain at least two different donor groups capable of chelation to metal ions by those groups as polydentate ligands. The most common donor atoms met are N, O, S, and P, although other donors such as group 14 elements (including C) are known. Whereas mixed...

The substituted metallocene compounds Cp2M(OSO2CF3)2 (Cp=η5-C5H5; M = Ti, Zr, Hf, Nb, Mo), CpTi(OSO2CF3)3·0.75(1,2-dimethoxyethane), and the organo-main group compounds (C6H5)3M′(OSO2CF3) (M′=Si, Ge), (C6H5)2Sn(OSO2CF3)2 and (C6H5)3Sb(OSO2CF3)2, were synthesized from the corresponding chloride or bromide compounds and silver trifluoromethanesulfona...

Methyl 2-[N-(2'-pyridylmethyl) carbamyl] pyridine-6-carboxylate (H1), prepared by reaction of a 1: 1 ratio of the methyl diester of pyridine-2,6-dicarboxylic acid and 2- aminomethylpyridine, can form 1: 2 M: L complexes by acting as a tridentate ligand, as exemplified by a crystal structure analysis of [Co-III( 1)(2)](ClO4) where each ligand is coo...

The hexadentate bispidine-based ligand 2,4-bis(2-pyridyl)-3,7-bis(2-methylenepyridine)-3,7-diazabicyclo[3.3.1]nonane-9-on-1,5-bis(carbonic acid methyl ester), L(6m), with four pyridine and two tertiary amine donors, based on a very rigid diazaadamantane-derived backbone, is coordinated to a range of metal ions. On the basis of experimental and comp...

The effect of effluent composition on the efficiency of hydroxide precipitation of Cd(II), using both lime and magnesia as precipitants, has been modelled by the solubility domain approach in order to provide wastewater effluent treatment limits, and has been experimentally validated. Common anionic species such as Cl−, SO42− and CO32− have been tr...

The versatility of palladium(II) as a template for Mannich-type macrocyclization is illustrated. Reaction of (bis(3-aminopropyl)piperazine)palladium(II) with formaldehyde and nitroethane in basic aqueous solution yields the ‘reinforced’ macrocycle 7-methyl-7-nitro-1,5,9,13-tetraazabicyclo[11.2.2]heptadecane as its palladium(II) complex. The crystal...

The potentially pentadentate ligand 2,6-bis[N-(2'-pyridylmethyl)carbamyl]pyridine (H2L1), readily prepared from reaction of a diester of pyridine-2,6-dicarboxylic acid (H2dipic) and 2-aminomethylpyridine (ampy), shows limited tendency to form 1:1 M:L complexes with labile metal ions, although [CuL1] and [NiL1] were observed as minor species, the la...

Digestion of Mn2O3 in a range of H2SO4 solutions (0.01–0 M), at a variety of temperatures (20–140 °C) has led to the formation of a series of kinetically stable manganese dioxide samples via a dissolution-precipitation mechanism that involves disproportionation of a soluble Mn(III) intermediate. The resultant manganese dioxide samples are character...

Oxidation of Mn(II) by HOCl in weakly acidic solution, in the presence of tungstate, results in the formation of the soluble heteropolyoxotungstate [MnW6O2]8-. The kinetics of formation of this species was studied from 15-35°C over the pH range 4.9-5.4 and found to exhibit solution autocatalytic behaviour. The oxidation kinetics was found to follow...

For Abstract see ChemInform Abstract in Full Text.

Transformation of calcium sulfate dihydrate (gypsum) into anhydrous calcium sulfate (anhydrite) proceeds slowly in a manganese sulfate/sulfuric acid medium (36 g Mn2+/kg of solution and 36 g H2SO4/kg of solution) at 95 °C, conditions pertinent to some industrial processes, without any apparent intermediate species. The kinetics of the transformatio...

In a facile carbon-acid condensation reaction of bis(2-aminomethylpyridine)copper(II) with nitroethane and formaldehyde in basic MeOH the N,N′-bis(2-pyridylmethylene)-1,3-(diamino-2-methyl-2-nitropropane)copper(II) cation is produced in essentially quantitative yield. The perchlorate salt crystallizes in space group P21en, a = 9.083(2), b = 15.198(...

The novel mixed salt of sodium acetate and perchlorate reported herein, Na4(OAc)3(ClO4), has a distinctive lattice structure formed from sodium acetate planes linked together by sodium perchlorate cylinders. In total contrast to the component salts, the structure contains channels parallel to the c axis. The integration of the two molecular-level s...

The four-strand and potentially N2O2-donor ligand 2,3-endo,endo-bis(aminomethyl)-5,6-endo,endo-bis(hydroxymethyl)bicyclo[2.2.1]heptane (L1), a close analogue of the known tetraalcohol 2,3,5,6-endo,endo,endo,endo-tetrakis(hydroxymethyl)bicyclo[2.2.1]heptane (L2), has been prepared via a multi-step synthesis and isolated as the copper(II) complex [Cu...

The recovery of gold and silver from ore in an ionic liquid is reported for the first time. The 1-butyl-3-methyl-imidazolium hydrogen sulfate ionic liquid (bmim+HSO4−) was employed, with iron(III) sulfate oxidant and thiourea added. Selective extraction of gold (≥85%) and silver (≥60%) from powdered ore (of dominantly chalcopyrite/pyrite/pyrrhotite...

Reaction of nickel(II) or copper(II) acetate with 2-(aminomethyl)pyridine 1 and pyridine-2,6-dicarboxylate ion 2 in aqueous methanol in a 1 : 1 : 1 molar ratio leads to the crystallization in high yield of exclusively one product in each case. For nickel(II), a neutral mixed-ligand complex [Ni · 1 · 2 · (OH2)] is obtained, whereas with copper(II) a...

l-3-Phenylpropane-1,2-diamine (dapp) was prepared by a three-step synthesis based on l-phenylalanine and characterized, including determination of stability constants with M2+ ions (Ni, Cu, Zn, Cd). The reaction of L-3-phenylpropane-1,2-diamine as the [Cu(dapp)2]2+ complex ion with formaldehyde and nitroethane in basic solution yields the acyclic (...

The analysis of gold by inductively coupled plasma atomic emission spectrometry (ICP-AES) in aqueous solution in the presence of up to 50% w/v of ionic liquid is reported. The ionic liquids investigated contain the 1-butyl-3-methyl-imidazolium (bmIm) cation with the anions Cl–, BF4–, HSO4–, or N(CN)2–. A facile route to the HSO4– salt is also descr...

The unsymmetric mixed-donor Nam,Npy,O-ligand N-trans-(2'-hydroxycyclohexyl)-2-aminomethylpyridine (pyca, 1) was readily prepared by reaction of an epoxide (cyclohexene oxide) with (2-aminomethyl)pyridine. The ligand forms octahedral bis-tridentate complexes, exemplified with isolation of copper(II), nickel(II), zinc(II), and cobalt(III) compounds;...

The nonamolybdomanganate ion (as (NH4)6[MnMo 9O32].6H2O) is a water-soluble manganese(IV) oxidant which is stable in the pH range 3.0-5.0, and oxidises iodide, sulfite and oxalate anions in solution. The kinetics of the iodide oxidation display autocatalytic behaviour, associated with catalysis by low-valent manganese ion formed in the reaction. A...

Selective leaching of synthetic Mn and Fe oxide phases was examined using a Chemostat to control the system temperature, pH and reductant concentration or Eh. Reaction conditions for the selective dissolution of model phases of Mn oxide (birnessite, 'MnO 2'), amorphous Fe oxyhydroxide (ferrihydrite, Fe(OH 3·xH 2O) and crystalline Fe oxide (hematite...

The chiral 2,5,8-triazabicyclo[7.4.01,9]tridecane (L1), an analogue of 1,4,7-triazacyclononane, (L2) that has a trans-cyclohexane ring fused to the tacn framework, forms bis complexes with a wide range of metal ions where two geometric forms may exist depending on the relative locations of the substituent cyclohexane units. For the crystal structur...

Selective leaching of synthetic Mn and Fe oxide phases were examined using a Chemostat to control the system temperature, pH and/or Eh. Reaction conditions for the selective dissolution of model phases of Mn oxide (birnessite, 'MnO 2'), amorphous Fe oxyhydroxide (ferrihydrite, Fe(OH) 3.xH 2O) and crystalline Fe oxide (hematite/goethite, Fe 2O 3/FeO...

The interaction of a series of N-benzylated cyclam ligand derivatives incorporating from one to four benzyl groups with nickel(II) and copper(II) is reported. The isolation of a selection of 1 : 1 (metal : ligand) complexes of both metals has been carried out and visible spectral, EPR, electrochemical and X-ray determinations have been employed to...

The effect of cadmium(II) on the transformation of ferrihydrite[with Cd(II):Fe(III) ratios ranging from 0 to 5 mole %] in neutral and alkaline media (pH 7-11), combined with the effects of electrolyte type (NO3 -, Cl-, and SO4 -2), was investigated at 20 C over a period of 1 yr. The presence of Cd(II) strongly retards the conversion of ferrihydrite...

Reaction of ethane-1,2-diamine with cyclohexene oxide produces the diaminodiol 1,2-bis(2′-hydroxycyclohexylamino)ethane. This undergoes an Okahara ring closure to produce a new diaazaoxa macrocycle 2,5-diaza-12-oxa[12.4.01,13.06,11]tricycloseptadecane, consisting of three fused rings with a core cyclononane unit containing an N2O heteroatom donor s...

Acid dissociation constants for a series of tetraazamonocycloalkanes of {13}–{15} membered ring sizes, as well as for a related reinforced {15R} tetraazabicycloalkane, each with one primary amine or carboxylate C-pendant, are reported. Further, formation constants with the metal ions ZnII, CdII, PbII, HgII, MnII and CoII have been determined. The l...

The major trans (1) and minor cis (2) isomers of 1,4,8,11-tetraazacyclotetradecane-6,13-dicarboxylate have been characterized as the complexes [Co(1)](ClO4) and [Co(H-2)(OH2)]Cl(ClO4).H2O. The former crystallized in the C-2/c space group and the latter in the P2(1)/c space group, with cell parameters a 16.258(7), b 9.050(3), c 15.413(6) Angstrom, b...

The complex anion [Fe(CN)5(NO)]2− (nitroprusside) has been defined intact using electrospray ionization mass spectrometry (ESIMS), with minor daughter ions predictable fragments of the parent [Fe(CN)5NO]2−. Direct evidence for ion pairing of [Fe(CN)5NO]2− with monovalent alkali metal and some alkylammonium cations was found independently using ESIM...

Reactions in ionic liquids for a range of applications involving metal ions and their compounds are described. Applications in organic synthesis are exemplified using organostannanes in environmentally friendly allylation reactions, and metal-directed macrocycle formation via Mannich-type reactions. In addition, applications in metal recovery are i...

The saturated, stereodefined tetraalcohol 2,3,5,6-endo,endo,endo,endo-tetrakis(hydroxymethyl)bicyclo[2.2.1]heptane (tetol, L1) and the simple alcohol butane-1,3-diol (L2) form complexes with alkali metal ions (lithium, sodium, potassium, rubidium and caesium), alkali earth cations (magnesium, calcium, strontium and barium) and Ga(III) and Ce(IV) in...

The cleavage of the RNA dimers GpA and ApUp is promoted by the inert cobalt(III) complex [Co(tren)(OH 2 )(OH)] 2+ (tren= N , N -bis(2-aminoethyl)ethane-1,2-diamine) the reactions being followed spectrophotometrically, with rate enhancements comparable to those observed for that complex reacting with the model phosphodiester bis( p -nitrophenyl)phos...

Base hydrolysis kinetics of chloropentaaminecobalt(III) complexes of a range of acyclic and cyclic pentaamine ligands, incorporating the rigid -NH-CH 2 -C(CH 3 )(NH 2 )-CH 2 -NH- motif, which must coordinate facially in octahedral complexes, are analysed in terms of ground state structural influences on hydrolysis rates. For complexes without exper...

The reaction of the acyclic complex ion (methyl (SS,SS)-3-[(2´-aminocyclohexyl)amino]-2-[(2´-aminocyclohexyl)-aminomethyl]propionate)copper(II) with formaldehyde and nitroethane in basic solution yields the pendant-arm macrocyclic complex (SS,SS)-(methyl-15-methyl-15-nitro-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane-4-carboxylate)copper(ii) io...