Cations copper

An alternative drivirg force could involve a donor - acceptor interaction. The electron-poor pyridine ring that is coordinated to the copper cation can act as electron acceptor with respect to the aromatic ring of the -amino acid. The fact that donating substituents on the amino acid increase the efficiency... 

Fonnation of a complex with a copper cation only further stimulates this behaviour. As a result, S.lg is almost completely bound to the micelles, even at low concentrations of Cu(DS)2. By contrast, the reaction of 5.1 f still benefits from an increasing surfactant concentration at 10 mM of Cu(DS)2. In fact, it is surprising that the reaction of this anionic compound is catalysed at all by an anionic surfactant. Probably it is the copper complex of 5.If, being overall cationic, that binds to the micelle. Not surprisingly, the neutral substrate S.lc shows intermediate behaviour. 

Finally, some orgatiocopper compounds undergo diarge disproporLionation under die influence of ligands dial bind strongly to copper. Treatment of mesityl-copper witli 1,2-bis-idipbenylpbospbinoJediane iDPPE), for example, results in tlie fotniation of bisimesityljcopper anions and a copper cation to wbidi four pbos-pborus atoms of two DPPE molecules ate coordinated [75]. 

By convention, the chemical formulas of many ionic compounds do not explicitly state the charges of the ions. It is not necessary to do so when the species involved form ions with only one possible charge. However, many metals form more than one type of stable cation. For example, copper forms two different oxides, black CuO and red C112 O. The oxide anion has a -2 charge, so for the first compound to be neutral the copper cation must bear a +2 charge. In C112 O, each copper ion must have +1 charge. 

Chemists would like to invent molecules that assemble themselves into specific, we 11-organized arrays. Recently there have been some exciting successes. Our inset is a molecular view of a self-assembled molecular wreath. This organized sfructure forms when four molecular chains weave themselves together in the presence of 12 copper cations. Self-assembling molecular systems could lead to new materials with useful properties. They may also shed light on how life originated. 

Each zinc atom transfers two eiectrons to a copper cation. Balanced half-reactions show the electron gains and... 

Blue copper proteins. A typical blue copper redox protein contains a single copper atom in a distorted tetrahedral environment. Copper performs the redox function of the protein by cycling between Cu and Cu. Usually the metal binds to two N atoms and two S atoms through a methionine, a cysteine, and two histidines. An example is plastocyanin, shown in Figure 20-29Z>. As their name implies, these molecules have a beautiful deep blue color that is attributed to photon-induced charge transfer from the sulfur atom of cysteine to the copper cation center. 

More recently, the El and electrospray ionization (ESI) mass spectra of 2,5-diaryl- and 2-arylamino-5-aryl-l,3,4-oxadiazoles, as well as their complexes with copper cations, were studied. Under ESI conditions, loss of NH3 and HNCO, from complexes of 2,5-diphenyl-l,3,4-oxadiazole, 2,5-bis(2-pyridyl)-l,3,4-oxadiazole, or 2,5-bis(4-pyridyl)-1,3,4-oxadiazole with copper cation, was observed <2004JMP272>. An unusual elimination of isocyanic acid was found in fragmentation of some protonated 2,5-diaryl derivatives <2002RCM390>. 

Valency is the number of electrons lost, borrowed or shared in a chemical bond. Formal charges are indicated with Arabic numerals, so the formal charge on a copper cation is expressed as Cu2+, meaning each copper cation has a deficiency of two electrons. In this system of thought, the charge on the central carbon of methane is zero. 

The same type of Au- -N interaction between adjacent [Au(CN)4] anions is found in [Cu(dien)][Au(CN)4]2 and [Cu(en)2][Au(CN)4]2 (dien = diethylenetriamine en = ethylenediamine) [48], although in these examples the copper cations act as bridges between neighboring chains generating 2-D sheets, as shown in Figure 5.26. The Au- -N separations, of 3.001 and 3.137 A in the triamine complex and 3.035(8) A in the diamine one are similar to those in other tetracyanoaurate(III) derivatives. Additional weak hydrogen bonds between amino hydrogen and N(cyano) atoms increase the dimensionality of the supramolecular structure. 

The reducibility of nickel and copper cations in Nb- and Al-containing MCM-41 It is known that transition metal cations, which occupy extra lattice positions in zeolites, are reduced while activated under vacuum or in an inert gas flow [20], The same occurs while applying mesoporous matrices for metal cations. The species formed during the auto reduction depend on the nature of a matrix, the conditions of cation modification, and activation They can be identified by H2-TPR, ESR, and NO/FTIR measurements. 

Freiberg M, Meyerstein D (1980) Reactions of aliphatic free radicals with copper cations in aqueous solution, part 2. Reactions with cupric ions a pulse radiolysis study. J Chem Soc Faraday Trans 176 1825-1837... 

An original approach to assemblies of rotaxanes was suggested by Schalley et al. [56], The authors synthesized a rotaxane 40 containing the bis-quinoline unit in its wheel component. Subsequent exo-coordination of copper cations leads to a copper-bridged bis(rotaxane) 41 with perpendicularly oriented axles. 

C. CU2SO3 is an ionic compound containing copper cation and the SO3 anion. Choice A is wrong because it uses the naming system for molecular compounds. The SO3 anion is 2- and is named sulfite. It takes two copper cations in to neutralize this charge, so Cu has a charge of 1 +, and the name is copper (I) sulfite. 

Nanocrystalline copper with an average crystallite size of about 50nm can be obtained without additives in the ionic liquid 1-butyl-l-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP]Tf2N) [92], Because of the limited solubility of the tested copper compounds in this ionic liquid, copper cations were introduced into the ionic liquid by anodic dissolution of a sacrificial copper electrode. The electrodeposition of copper was also investigated in the ionic liquid... 

Superoxide dismutase turns out to be the key mammalian antioxidant enzyme. SOD is essential genetically modified mice lacking the enzyme die shortly after birth. It exists in several forms but the most closely studied version is SOD1, a protein containing zinc and copper. The catalytic site, shown in Fig. 4.11, contains a copper cation held by three neutral histidines and one histidine anion which in turn is bound to a zinc atom. 

An X-ray structure analysis was carried out 179) on a single crystal of natural faujasite which had been exchanged with Cu2+ ions, dehydrated, and then exposed to butadiene. The major effect of adsorbing butadiene was to induce a migration of copper cations to site III, located at the pore entrances to the supercages (see Fig. 17). The unsaturated coordination of... 

Copper cation conductors - solid electrolyte Copper-conducting solid electrolyte - solid electrolyte... 

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