Metal ions, incarcerates

Very recently, a novel and versatile method has been reported for the construction of stable, zero-valent metal quantum dots, using dendrimers as well-defined nano-template/containers. The concept involves the use of dendrimers as hosts to preorganize small molecules or metal ions, followed by a simple in situ reaction, which immobilizes and incarcerates these nanodomains (Figure 17) [89]. The size, shape, size distribution, and surface functionality of the dendritic nanocomposites are determined and controlled by the architecture. Dendrimer-based nanocomposites display unique physical and chemical properties as a consequence of the atomic/molecular level interactions between the guest and host components within the dendrimer as well as the dendrimer interaction with various solvents and media. 

Crystal structure and electrochemistry of Sc Cg2(Ad) (Ad = adamantylidene) (in the C2v(9) isomeric form) have been reported [13], We report in Table 51.3 the redox potentials of its electron transfer processes together with those of the precursor Sc C2v(9)Cg2. In both derivatives, the authors assigned the oxidation state -1-3 to the incarcerated metal ion. We note that, in previous studies, the oxidation state -1-2 has been assigned to Sc Cg2 [20]. 

Going on. Fig. 51.6 shows the different redox changes exhibited by Y Cg2(Ad) (Ad = adamantylidene) [14b] with respect to the pristine precursor. Also, in this case, the oxidation state -1-3 is assigned to the incarcerated metal ion in both the adamantylidene adduct [14b] and the pristine derivative [21b]. Also in this case, previous studies assigned the oxidation state -1-2 to Y Cg2 [20a]. 

It is noted that in spite of the formally negative charge of the Cg2 cage (namely, 3-) induced by the incarcerated M + ion, the oxidation processes of the EMFs are more difficult and the reduction processes are easier with respect to the corresponding processes of free Cg2. Excluding obviously Coulombic effects, this means that the intramolecular metal ion/fullerene electron exchange modifies appreciably the nature of both the HOMO and LUMO levels with respect to those of free Cg2. as on the other hand theoretically proved [21c, 24]. 

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