Silver isolated sites

Figure 3.2 STM images obtained with a CO-terminated tip, Vt = 70 mV and /t= 1 nA. (a) Isolated CO molecule, (b) two O atoms (adsorbed on the nearest fourfold hollow sites along the [1 1 0] direction), (c) CO and two O atoms separated by 6.1 A along the [0 0 1] direction, and (e) O-CO-O complex. Grid lines are drawn through the silver surface atoms. Scan area of (a-c) and (e) is 25 A x 25 A.

We have prepared a variety of new Schiff base bis crown ether ligands (98-100) that contain alkali and transition metal coordinating sites via the condensation of two or three equivalents of 4-formyl-benzo-15-crown-5 with an appropriate di- or triamine (Scheme 18). Homometallic copper(I), silver(I), and heteropolymetallic copper(I)-sodium, silver-(I)-sodium, and potassium complexes have been isolated. The singlecrystal X-ray structure of the [Cu(57)K](PF6)2 complex (100) is shown... 

These results demonstrate that beginning with isolated silver atoms in the samples AgsNaY, an increase in silver ion concentration induces a growth in the population of Ag + species, via a progressive occupancy of site I adjacent to site I. Taking into account the site occupancies obtained by Uytterhoeven (3) for... 

The sulfur-containing receptors have little affinity for hard cations but can form extractable host-guest complexes with soft cations such as Ag+, Hg +, T1+, Pd +, and Pt +. Silver is found to interact strongly with sulfur [138, 139]. It was even possible to isolate 1 1 host-guest silver and mercury complexes in a large sulfur-containing macrocycle a linear HgC molecule is hosted in the cavity, but in the 1 2 complex a second mercury atom is externally attached to the ruthenium atom [140-142]. Palladium and platinum are also selectively complexed by polythia-coronands [143-148]. Some X-ray diffraction studies on palladium [147, 148] and platinum [143, 145] complexes established that the coordination of the metal occurs by interaction with the sulfur sites. 

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