Copper complex irradiation

Copper speciation in water was investigated by means of spectrophotometry of Cu+-bathocuprine complex formation (Bjoerklund and Morrison, 1997). The complex was separated by means of solid-phase extraction on PTFE-supported octadecyl (Qg) bonded silica discs. The discs provided rapid filtration and contributed low blanks. After filtration, the copper complex was eluted, and the copper concentration was measured by spectrophotometry. Total copper concentrations in the samples were measured after UV irradiation. The bathocuprine-available copper detection limits (for 500 ml samples) were 0.4 and 3.8 mg dm-3 copper for pure and polluted water, respectively. 

A large class of coordination compounds, metal chelates, is represented in relation to microwave treatment by a relatively small number of reported data, mainly p-diketonates. Thus, volatile copper) II) acetylacetonate was used for the preparation of copper thin films in Ar — H2 atmosphere at ambient temperature by microwave plasma-enhanced chemical vapor deposition (CVD) [735a]. The formed pure copper films with a resistance of 2 3 pS2 cm were deposited on Si substrates. It is noted that oxygen atoms were never detected in the deposited material since Cu — O intramolecular bonds are totally broken by microwave plasma-assisted decomposition of the copper complex. Another acetylacetonate, Zr(acac)4, was prepared from its hydrate Zr(acac)4 10H2O by microwave dehydration of the latter [726]. It is shown [704] that microwave treatment is an effective dehydration technique for various compounds and materials. Use of microwave irradiation in the synthesis of some transition metal phthalocyanines is reported in Sec. 5.1.1. Their relatives - porphyrins - were also obtained in this way [735b]. 

The first step in this new stain protocol employs copper acetate, a metal salt that is both a good fixative ( ) and a silver stain enhancer. The mechanism of copper s stain enhancement, in this and other silver stains, may be similar to its action in the biuret reaction (15.), in which a characteristic color shift, from violet to pink, is achieved by titrating peptides in the presence of copper ions. Copper complexes formed with the N-peptide atoms of the peptide bonds are primarily responsible for this reaction. There are also some number of secondary sites which may interact with copper. Any elemental copper formed may displace positive silver ions from solution as copper has a greater tendency to donate electrons than silver, indicated by its position in the electromotive series of the elements. Following the treatment with copper acetate, the membrane is sequentially soaked in a solution containing chloride and citrate ions and then in a solution containing silver nitrate. The membrane is then irradiated with light while it is in the silver nitrate... 

The Cu-Zn-SOD-mimetic activity of Cu(II)(3,5-DIPS)2 and its lipid solubility were criteria used to select this complex in the initial attempt to study a copper complex as a radioprotectant. This complex was found to prevent death in 58% of the lethally irradiated (10 Gy, 0.4Gy/min) mice when they were thought to have been treated with 0.49 mmol/kg, 3 h before irradiation [505]. Subsequent studies revealed that this protection could be achieved with a much lower dose of complex suspended in a propyleneglycol-poly(vinyl alcohol)-saline vehicle. Treatment with 0.16 mmol/kg produced a 60% increase in survival in similarly irradiated and treated mice [506]. Most recent studies suggest that this radioprotectant effect may be achieved with a still further reduced dose of 0.04 mmol/kg and this lower dose appears to be as effective if given 3 h after irradiation as it is when given 3 h before irradiation. 

A review of the photochemical properties of copper complexes includes a survey of the photocatalysed reactions of copper-olefin complexes. The addition of acetonitrile to norbornene may be induced by irradiation in the presence of silver ions. The reaction appears to involve excitation of a LMCT excited state of the norbomene-silver complexes and the formation of norbornene radical cations. 

Ozawa et al. have performed crystal structural analyses on these dinuclear copper complexes in the excited state while irradiating the crystal with CW laser [6]. In their experiment, the interatomic distance between the two copper atoms is almost the same, whereas that between the two bromine atoms is shortened in the excited state. The structural change is reported to be about 10 %. In the excited state, the electron in the copper 3d orbital slightly moved outside from the Cu2Br2 unit plane due to MLCT. Thus, the intermolecular distance between the two bromine atoms is shortened due to the expansion of the two copper atomic orbitals. Luminescence can be explained by the electron in the ligand molecular orbital dropping into the copper 3d and bromine 4p orbitals. 

The application of inexpensive photoactive copper complexes has given great impulse to visible light-mediated photoredox catalysis, e.g. for C-C and C-N coupling reactions. Irradiation of Cu-complexes both triggers metal centred single electron transfer processes and assists the Cu-catalysed elemental steps, in which the substrate is covalently bonded. Successful extension of cooperative copper photocatalysis to other reactions is expected for the near future. " ... 

Copper-mediated alkynylations of alkenyl- or aryl-substituted compounds should be considered as variations of the original Castro-Stephens reaction under catalytic reaction conditions. Copper(I) salts stabilized by aryl-substituted phosphines can mediate the coupling of aryl iodides in polar aprotic solvents using either conventional heating [87] or microwave irradiation [88]. More recently, weU-defined 1,10-phenanthroline-derived copper complexes were shown to be effective catalysts for the coupling of activated and deactivated aryl iodides at 10mol% catalyst loading in an apolar solvent (Scheme 6.29) [89]. 

The oxidation of copper(i)-olefin complexes by O2 has been reported. The copper complexes were prepared pulse-radiolytically by rapid reduction of Cu in the presence of ethylene or allyl alcohol. The irradiated solution was then mixed with oxygenated water in a stopped-flow apparatus. For the two complexes described the rate laws differ only slightly. In the reaction with the ethylene (L) species the rate law obtained is... 

Copper(i) co-ordinates with both double bonds but not the hydroxy-group of (CH2=CHCH2)a CHOH in the CuOTf complex. Irradiation of the CT bond of the complex leads to the formation of endo- and eAru-bicyclo-[3,2,0]heptane-3-ol. 

---