Ionically bound clusters

Large metal clusters have been supported on many metal oxides. For example, the carbido-cluster anion [OsioC(CO)24] has been adsorbed directly onto MgO. This cluster anion can also be prepared in situ on MgO by the Reductive Carbonylation of adsorbed H2OSCI6. The adsorbed osmium cluster anion appears to be ionically bound to the surface. 

Example Ionic liquids (ILs) are perfect representatives of ionic analytes. LIFDI (essentially FD, cf. Chap. 8.6) spectra of ILs such as IV-hexylpyridinium tetrafluoroborate (Fig. 8.19) are dominated by the cation peak, C here at tn/z 164, that is accompanied by a strong first cluster ion signal, [(C 2+BF4T at m/z 415, and by a weak second cluster ion signal. The corresponding boron isotopic patterns (Bi and B2) are clearly visible. Furthermore, the softness of the FD process is demonstrated by the fact that even the weakly bound cluster ions exhibit almost no fragmentation in metastable ion spectra, but require collisions to induce dissociation [116]. 

Table 6.2 shows the detachment energy of one water molecule from a hydrated halide ion cluster [41]. The strength of the water-halide interactions is reduced as the ionic radius increases in the order of Fspecific adsorption in an electrochemical environment. It is clear that the nonspecific adsorption behavior of F is due to its strongly bound solvation shell. Due to... 

The first type of relaxation processes reflects characteristics inherent to the dynamics of single droplet components. The collective motions of the surfactant molecule head groups at the interface with the water phase can also contribute to relaxations of this type. This type can also be related to various components of the system containing active dipole groups, such as cosurfactant, bound, and free water. The bound water is located near the interface, while free water, located more than a few molecule diameters away from the interface, is hardly influenced by the polar or ion groups. For ionic microemulsions, the relaxation contributions of this type are expected to be related to the various processes associated with the movement of ions and/ or surfactant counterions relative to the droplets and their organized clusters and interfaces [113,146]. 

The most important point in this study is that the dipole-bound excited states of the 1 (CH3CN)2 cluster cannot be considered as a result of further solvation of the [I-CH3CN]- ion core. Instead, the nature of diffuse excited states is determined by the entire arrangement of solvent molecules around the solute anion, as mentioned above. This situation is more akin to CTTS in bulk solutions than solvated ion cores, which are common to most ionic clusters and electrolytic solutions without photoexcitation. 

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