Copper triangles

Linked copper triangles are also found in [Cu6(0H)2(pz)6(N03)4(Hpz)g] (Hpz = pyrazole). Each triangle has a central hydroxide group, with each edge of the triangle bridged by a pyrazolate... 

Fig. 8. The adsorption of hydrogen on copper-nickel catalysts as a function of the copper content. The circles represent the total amount of hydrogen adsorbed at room temperature at 10-cm pressure. The triangles represent the amount of strongly adsorbed hydrogen, i.e., the amount not removed by a 10-min evacuation at room temperature following the completion of the initial adsorption isotherm. The amount of strongly adsorbed hydrogen is determined as the difference between the initial isotherm and a subsequent isotherm obtained after a 10-min evacuation (74).

Figure 2 Dependence of calculated adsorption site concentration on the copper loading B in Cu-Na-FER (hollow squares), B in Cu-K-FER (filled squares), D (triangles) and B + D (circles) in Cu-K-FER.

Fig. 13. The temperature dependence of the precessional amplitudes (left) and relaxation rates (right) of the muonium centers observed in the copper halides. The open and filled triangles or squares are for Mu7 and Mu77 respectively. Note the similarity of the Cul data to that for Mu7 in CuCl and CuBr, suggesting that a transition to another center occurs in Cul but that the product has not been observed. From Kiefl et al. (1986b).

Venus Center (Copper) VA VAy ) White crescent charged with a red triangle. 

If one wants to understand why such changes occur, one can look at a few of the basic equilibrium properties of such complexes. Figure 1 illustrates the trends which occur when a sample is titrated with copper, monitoring three different parameters. The black dots indicate the relative amount of bound copper as indicated by free copper ions sensed with an ion-selective electrode (Xc of left ordinate). The triangles represent the change of the absorbance of the solution at 465 nm (right ordinate). The curve with the open circles is the relative quenching of the fulvic acid fluorescence (Q of left ordinate). We see that we are able to probe several different types of sites with different types of probes for this multidentate system. 

Rh (172)]. These species merit comparison to the rhenium- and manganese-dicopper species 158 and 159, which have molecular mirror symmetry and a V-shaped trimetal unit that lacks a Cu-Cu bond. Although 171 and 172 appear symmetric in solution on the NMR time scale due to fluxional processes, in the solid state the two copper centers are clearly inequivalent and a Cu-Cu bond is present. The metal triangle is supported by two B-H Cu linkages, one to each Cu center, involving p- and y-B H vertexes in the M -bound CBBBBEi belt. 

Fig. 5 Relationship between the amount of graft polymers and Mn of free polymers. The graft polymerization was carried out under various conditions on silicon wafer (squares), silica particles with varying diameter (d = 12, 130, 290, 740, 1550 nm) (circles), and silica monolith with 50-nm mesopores (triangles). Two types of immobilized initiators, 2 and 5 (n = 6 and R" = CH3) in Fig. 2, two types of copper halides, CuBr and CnCl, and two types of ligands, spartein (Sp) and dipyridyl derivatives (4,4 -diheptyl-2,2 -dipyridyl (dHbipy) and 4,4 -dinonyl-2,2 -dipyridyl (dNbipy)), were used...

Figure 17.32 Photoaction spectra obtained in presence of Cu(I)/Cu(II) electron mediators using regenerative sandwich cells equipped with gold counter electrodes. (5) Stars, (1) open circles, (4) open triangles, (2) solid triangles, (3) open squares, and (6) solid circles. Data compared with the F/I3 couple (black squares). Li+ 0.5 M was added to all copper-based electrolytes.

Figure C3.1.3 Comparison of lipase activities using the copper soap colorimetric assay as affected by the degree of homogenization of olive oil substrate. The lipase used in the reaction mixture was from C. rugosa (at 0.40 mg/ml) in the presence mechanically homogenized (triangles) or poorly homogenized (shaken by hand diamonds) substrate emulsion. For comparison of linearity of reaction progress curves, the time course of C. rugosa lipase (at 0.20 mg/ml circles) is provided.

In each graph and illustrated in Figure 1 is an example, which also serves the following Figures 2-8, the diamond icons represent the copper percentage of a specimen, the triangles represent the lead percentages, the circles the tin,... 

Figure 3.2 The Leden-Chatt triangle with copper at the apex. A useful way to remember some of the soft metal ions.

Fig. 8. tma-molecules bond in a flat adsorption geometry at a copper surface and are resolved as equilateral triangle in STM. The sequence of STM images reveals how the thermal motion of molecules at the surface proceed following tma rotational motions and displacements a Cu atom is captured whereupon a cloverleaf-shaped Cu(tma)4 coordination compound evolves (second image for t = 80s, central Cu atom highlighted in red) [87],... 

Type IV. Trinuclear copper site having an isosceles triangle shape two copper ions are strongly magnetically coupled. 

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