Copper compounds interactions

The literature dealing with EPR studies of transition metal dithiocarbamato complexes is extensive. Interesting results were obtained about the interaction of copper compounds with various solvents 165,166,167,168) and about dimer formation of Cu(R2frozen solutions, 133,169) whereas extensive EPR studies about other transition metal dithiocarbamato complexes are reported as well 170,5,171, 37). As the measurements of the planar systems are most suitable for comparison with theoretical studies, we shall pay attention to the results of these investigations on Cu(II), Ag(II) and Au(II). 

In a few instances, binuclear complexes have been reported in which the two copper atoms interact directly through a metal-metal bond. Two examples of such complexes are illustrated below [192, 193]. CV s run on the compound at left in both tetrahydrofuran and CH2CI2 indicated the presence of two separate electron-transfer steps that were quasi-reversible. 

Pybum, C. M., F. P. Cahill, and R. K. Lennox. 1978. Sulfur compound interactions on copper corrosion test in propane. Energy ProcessingICanada. March-April, pp. 60-64. 

The P-P band is ahrnys filled, corresponding 10 a P—P bond (225 pm) in the copper compound. At the other extreme, the P-P band it also filled, giving an antibonding interaction in addition. Thus, overall, there is a nonhonded interaction between the two phosphorus atoms and so we should not be surprised that the P-P distance is approximately twice the van der Waats radius or phosphorus (2 x 185 pm 384 pm) We can view the progression from Mn to Cu as a redox tuning of the occupancy of these energy levels 38... 

The X-ray structure of the CO-bound fully reduced form was also determined at 2.8-A resolution (Fig. 5C, see color insert) (Yoshikawa et al., 1998). The structure of the O2 reduction site shows that CO coordinates to Foaj in a bent end-on fashion. The distances of Fea,—C and Cub—O are 1.90 and 2.47 A, respectively. The Cub—O distance, 2.47 A, indicates very weak interactions between the two atoms. This structure is consistent with the infrared results as described below. The stability of the cuprous copper compound in the trigonal planar coordination provides the weak interaction. 

The current theory on the mode of action of copper compounds is that the copper ion, Cu, is the active component, which is released from the different salts on the leaf surfaces. The copper ions in the presence of CO2 from the air and the organic acids excreted from the plant and/or fungal spores interact together to produce the resultant activity. The copper ions and complex-bound copper are capable of penetrating the spores and lead to the inhibition of enzyme reactions. This can occur by the removal of other important metals from their compounds by chelation and also by blocking or interacting with the sulfhydryl groups of the spore enzymes. 

The relatively small changes in the geometrical and electronic configuration of the copper compound shown in the uppermost curves in Fig. 1.12 and in the two upper curves a and b in Fig. 9.15 are apparently sufficient to partially lift its one-dimensionality by increasing the interstack interactions via the bonds between the central Cu ion and the CN groups of the DCNQI. Here, the Cu " d states (d ) medi-... 

Copper interacts with numerous compounds normally found in natural waters. The amounts of the various copper compounds and complexes present in solution depend on water pH, temperature, and alkalinity and on the concentrations of bicarbonate, sulfide, and organic ligands. In animals, copper interacts with essential trace elements such as iron, zinc, molybdenum, manganese, nickel, and selenium and also with nonessential elements including silver, cadmium, mercury, and lead interactions may be either beneficial or harmful to the organism. The patterns of copper accumulation, metabolism, and toxicity from these interactions frequently differ from those produced by copper alone. Acknowledgment of these interactions is essential for understanding copper toxicokinetics. 

Density measurements of mannitol in potassium or sodium acetate solutions have revealed the nature of solute-solvent interactions in these mixtures and the kinetics of oxidation of several hexitols (and cyclitols) by molecular oxygen, catalysed by copper compounds, has been studied. ... 

In cyclopentadienyl compounds of copper such as [Cucp(CO)] and [Cucp(PR3)] (R = Et, Bu, Ph) the C5H5 group is a pentahapto ligand. Formally these compounds have 18 valence electrons. However, because of a considerable lowering of the energy of M copper orbitals and a substantial increase in the energy difference between the Ap and As orbitals, the orbitals of copper probably interact weakly with the orbi-... 

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