The dissolution of copper metal in the presence of copper(II) ions and allyl alcohol in aqueous solution is found to be pseudo-first order with respect to both copper(II) ions and allyl alcohol. The reaction is inhibited by acid. The rate determining step is not the formation of copper(I) but the transfer of electrons from the surface of copper metal to the copper(II) ions in solution. The reaction rate has been monitored spectrophotometrically by complexing the copper(I) formed with 2,9-dimethylphenanthroline (neocuproin) and measuring the absorbance of the solution at the wavelength of maximum absorption of the complex, 450 nm. Other factors that affect the reaction are the presence of anions, the solvent composition, the nature of the unsaturated ligand used to stabilize the copper(I) and the rate of stirring. The reduction of copper(II)-neocuproin by allylamine and allyl alcohol has been studied in basic solution. A method has been developed for the rapid, sensitive determination of CN⁻ based on a spectrophotometric technique using copper(I)-neocuproin as a reagent. SCN⁻ does not interfere but S²⁻ appears to be a very powerful source of interference. By appropriate choice of the concentration of copper(I)-neocuproin reagent the range of response can be adjusted to be in the range 1-10 ppm. The theoretical detection limit of the method is as low as 19 ppb at the 95% confidence limit and the precision, measured as the relative standard deviation, is better than 1.5%. The disturbance of the equilibrium between the bis ligand and mono ligand complexes of copper(I) appears to be the reason for the observed decrease in absorbance on the addition of cyanide to a solution of copper(II)-neocuproin. The problems associated with using the commercially available ion selective electrode for cupric determination have been highlighted. The possibility of developing a PVC matrix membrane electrode for the determination of CN⁻ has been explored. The main difficulty is the instability of the copper(I)-neocuproin complex at pH values as high as 11 that are required to stabilize CN⁻.

No description available.

[From Introduction]. This thesis deals with the determination of copper and nickel both separately and in each other's presence. The work is divided into two sections, one of which treats the subject from the theoretical side while the other contains an account of the practical work performed by the author. In the theoretical section, an attempt is made to summarise the better-known methods for the determination of copper and nickel, and at the same time, to incorporate such improvements, criticism and variations as have appeared in the literature. The subject is so vast that its summary in so short a space must necessarily be incomplete. Yoe and Server, for example, quote 111 references on the subject of the nickel-dimethylglyoxine with other ions. Only a fraction of the literature was available, and space permitted only a fraction of this to be abstracted in the following pages.

An investigation was conducted on the dissolution of copper metal in aqueous solutions of ethylenediamine, glycine, α-alanine and β-alanine, under oxygen pressure. The kinetics of these reactions were investigated over a wide concentration range of the corresponding ionized species. The rate of dissolution of copper, in all solutions, has been found to be independent of the initial copper concentration, the volume of the solution and the area of the copper sample. No intermediate products, i.e., cuprous ions, were observed. Two regions were observed, having different dependence on oxygen pressure. In one, the rate depends on the first power of the oxygen pressure, and is independent of the concentration of the chelating agent. In the other region, the reaction is first order in chelating agent and independent of oxygen pressure. The rate of the reaction in this second region appears to be chemically controlled at the copper surface. The neutral and charged species of the chelating agent were found to have independent rates. These two dissolution reactions were found to be first order with respect to the concentration of the respective complexing species. The mechanism proposed by Halpern previously for the ammonia system was found to be applicable to the systems studied in the present work. The rate constants for each chelating agent have been computed and appear to be related to the stability constants. No steric effect was observed. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

Several Schiff base ligands, N, N‟-(aryl)benzyaldiimine ligands (R-BEN); N, N‟-(aryl)benzyaldiamine dihydrochloride ligands (R-BENH•2HCl); N, N‟-(aryl)benzyaldiamine ligands (R-BENH); N, N‟-bis(cinnamaldiimine) ligands (R-CA2EN) were synthesized for the investigation of the electronic effect of the substituents at para-position of the Schiff base ligands and their copper complexes. The synthesis of Schiff bases was carried out by reacting a series of para-substituted benzyaldehyde, and para-substituted cinnamaldehyde with ethylenediamine. The imine group of Schiff bases, N, N‟-(aryl)benzyaldiimine ligands and N, N‟-bis(cinnamaldiimine)ligands were reduced to corresponding amines with sodium borohydride in methanol These ligands, N, N‟-(aryl)benzyaldiamine ligands (H-BENH), N, N‟-bis(cinnamaldiimine)ligands (CA2EN) were reacted with copper(II) dihalide and copper(I) monohalide ions respectively to form complexes. The ligands and their complexes were analysed using elemental analyses, FT-IR spectroscopy (mid-IR), UV/vis in aprotic and protic solvents,while mass spectrometry, 1H-NMR and 13C-NMR were used to further analyse the ligands. By using substituent parameters, both the single and dual substituent parameters with the spectroscopic data obtained from the spectroscopic techiques mentioned above, it was hoped to monitor and determine whether the electronic effects (resonance or inductive effcets) was predominantly within the Schiff base ligands and copper complexes. The NMR studies with dual substituent parameters suggest that the effects of the substituents are transimitted through the ligands, via resonance effects and that the phenyl group is nonplanar with the azomethine in N, N‟-(aryl)benzyaldiimine ligands. The presence of an extra double bond in Schiff base {(N, N‟-bis(cinnamaldiimine) ligand)} altered the electron density. The UV/vis studies showed that the symmetry of the N, N‟-bis(4-R-benzyl)-1, 2-diaminoethanedihalidecopper(II) complexes were predominantly tetrahedral for both chloro and bromo complexes. The correlation studies from mid-infrared were beneficial in monitoring the effect experienced by N, N‟-(aryl)benzaldiimine ligands, the studies suggest that the inductive effect is more pronounced at the C=N.

Chapter 1 reviews the coordination behaviour of the 6-diphenylphosphino-2,2'-bipyridine, 6-anilino-2,2'-bipyridine, 2,2'-bipyridyl-6-one, 6-N-methylanilino-2,2'-bipyridine, 6-piperidyl-2,2'-bipyridine and 2-(phenylamino)-1,10-phenanthroline ligands. These ligands are all tridentate and contain well established chelating fragments viz., 2,2'-bipyridine and 1,10-phenanthroline. Thus the review of their coordination provides insight into the expected coordination of the 2-diphenylphosphino-1,10-phenanthroline (Ph2Pphen) ligand. The synthesis and characterisation of this ligand is described in Chapter 2. Chapter 3 describes the synthesis and characterisation of a range of Ph2Pphen ligand-bridged dicopper(l) complexes. It has been shown that Ph2Pphen reacts with a suitable copper(l) precursor, [Cu(MeCN)4]+, to form the versatile dinuclear [Cu2(u-Ph2Pphen)2(MeCN)2]2+complex cation containing two bridging Ph2Pphen ligands; the structure of the SbF6 salt of this complex has been determined X-ray crystallographically. This complex possesses labile acetonitrile ligands which have been substituted by a variety of neutral and anionic ligands. Complexes prepared this way include [Cu2(u-Ph2Pphen)2(u-CI)]+, [Cu2(u-Ph2Pphen)2(u-I)]+, [Cu2(u-Ph2Pphen)2(py)2]2 +, [Cu2(u-Ph2Pphen)2{u-S2CN(Et)2}]+, [Cu2(u-Ph2Pphen)2(n-bipy)]2+ and [Cu2(u-Ph2Pphen)2(n-phen)]2+. X-ray structure determinations have been completed for [Cu2(u-Ph2Pphen)2{u-S2CN(Et)2}]+ and [Cu2(u-Ph2Pphen)2(n-bipy)]2+. The X-ray crystal structures of these ligand-bridged complexes confirm that the phosphorus atom coordinates to one copper atom while the phenanthroline fragment chelates to the other copper atom with the result that each metal atom has a tetrahedral geometry. Chapter 4 reviews the synthesis and characterisation of palladium and platinum complexes of the 2-diphenylphosphino-1, 10-phenanthroline (Ph2Pphen) ligand. The comproportionation reaction with Pd(II) and Pd(0) afforded the dinuclear complex [Pd2(u-Ph2Pphen)2](BF4)2. The reaction of Ph2Pphen with platinum resulted in ill-defined products that could not be isolated and characterised. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998

Master thesis named „Creation of logistic concept in the selected company“ is focused on detailed analysis of material flow of waste in manufacturing company. The main objective of thesis is proposal of new logistic concept of handling with copper waste, which is created during the manufacturing processes, which function will be to remove defects in material flow, to shorten the handling time with copper waste and more accurate information flow, considering work safety, costs and time.

The area of study for this project was the development of an accurate, reliable, and inexpensive method of trace analysis for copper, cadmium, and lead in foods. AT this time, the Association of Official Analytical Chemists Manual, eleventh edition, (4) has only official and recognized methods of analysis for copper (25.023), cadmium (25.018), and lead (25.041). In general, these procedures are long and tedious. The digestions involved often require many hours and are quite dangerous due to leakage of metallic and organometallic fumes from the digestion apparatus. The official methods of analysis for these elements require a very large outlay of money for special equipment and reagents. It was the purpose of this project to determine the following: (A) The feasibility of using polarographic detection for copper, cadmium, and lead in trace amounts.; (B) Fina da new method of sample decomposition to replace the present digestion methods.; (C) Study the selection media prior to polarographic detection.; (D) Develop a method of simultaneous polarographic detection of copper, cadmium, and lead.

The work described in this thesis concerns the synthesis and study of the coordination behaviour of the 6-anilino-2,2'-bipyridyl (Habipy), 6-N-methylanilino-2,2'-bipyridyl (mabipy), 6-piperidyl2,2'.- bipyridyl (pipbipy) and 2,2'-bipyridin-6-one (Hobipy) ligands. Chapter one reviews the coordination chemistry of the 2-aminopyridyl (Rap), 2-hydroxypyridyl (Hhp) and the 2-(2-pyridyl)-I,8-naphthyridine (pynp) ligands. These ligands are closely related to Habipy, mabipy, pipbipy and Hobipy in that they share a common NCN or NCO fragment. Thus the review of their coordination behaviour provides insight into the expected coordination of the Habipy, mabipy, pipbipy and Hobipy ligands. The synthesis and characteristaion of the novel Habipy, mabipy and pipbipy ligands are reported in Chapter two. X-ray crystal structure determinations of mabipy and pipbipy reveal that the geometry about the exocyclic nitrogen atom in both ligands is nearly planer, suggesting substantial overlap of the nitrogen lone pair orbital with the 1t electron system of the bipyridyl rings. In both mabipy and pipbipy the N3-C 10 bond lengths are shorter then normal N-C single bonds. In Chapter three -the synthesis and characterisation of copper(I) complexes containing mabipy, pipbipy and Habipy, and a copper(II) complex containing mabipy are reported. The copper(I) complexes have the general formula [Cu(l12-L)2r, where L= mabipy 1, pipbipy 2 or Habipy 3. The structures of complexes 1 and 2 are determined by X-ray crystallography. In complexes 1- 3 the bipyridyl fragments of mabipy, pipbipy and Habipy chelate while the exocyclic nitrogen atoms remain free. The crystal structures of 1 and 2 reveal that the exocyclic nitrogens have a planar geometry as was the case in the uncoordinated ligand. The crystal structure of [Cu(1l2-mabipY)2f+ (4) is determined by X-ray crystallography and is very similar to that of the copper(I) species. Coordination of the mabipy ligand in 4 is the same as that in 1 and the exocyclic nitrogen in 4 is also planar. The redox couple 4/1 is shown to be electrochemically reversible with EV2= 0.45 V. In Chapter four the synthesis and chararcterisation of dinuclear complexes containing the Ru2 2+, Ru/+, Mo24+and ~4+ cores are reported in which the abipy ligand bridges two metal centres. The complexes [Rulll-L)lCO)4], where L= abipy 5 or obipy 6, were synthesised by the r~action of the free ligands with [{RuiCO)102CCH3)2}n] in toluene. The structures of5 and 6 are determined by X-ray crystallography and show the ligands bridging the Ru(I) atoms in a head to tail fashion and occupy mutually cis positions about the octahedral Ru(I) atoms. The Ru-Ru separations in 5 and 6 are 2.668(1) and 2.671(1) A respectively. The reaction of Habipy with [Rui02CCH3)4CI]n was found to afford the mixed valence species [Ruill-abipy)(02CCH3)3CI] (7), the structure of which is determined by X-ray diffraction methods. The structure of7 reveals one abipy ligand bridging the two ruthenium atoms as in 5. The Ru-Ru separation in 7 is 2.294(2) A. The reaction of [Moi02CCH3)4] with habipy in methanol affords (Moill-abipy)(02CCH3)3] (8). The structure of 8 is determined by X-ray diffraction methods and reveals one abipy ligand bridging two quadruply bonded molybdenum atoms which have a Mo-Mo separation of 2.094(2) A. The [Rhlll~abipy)(02CCH3)iH20)] (9) is formed from the reaction of [Rh i02CCH3)4] with Habipy in methanol. The structure of [Rh2(Il-abipy)(02CCH3)iNCPh)] is determined by X-ray diffraction methods and shows the abipy ligand bridging two Rh(II) atoms which are separated by 2.399(1) A. This chapter is concluded with a discussion of the possiblity of substitution of more than one acetate ligand by the abipy ligand in terms of 'hard' and' soft' acid-base theory and synthetic methods. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1996.