High Temperature Dendrimer Removal

Since mild activation conditions appear to be important, a number of solution activation conditions were tested. PAMAM dendrimers are comprised of amide bonds, so the favorable conditions for refro-Michael addition reactions, (low pH, high temperature and the presence of water) may be able to cleave these bonds. Table 1 shows a series of reaction tests using various acid/solvent combinations to activate the dendrimer amide bonds. Characterization of the solution-activated catalysts with Atomic Absorption spectroscopy, FTIR spectroscopy and FTIR spectroscopy of adsorbed CO indicated that the solution activation generally resulted in Pt loss. Appropriate choice of solvent and acid, particularly EtOH/HOAc, minimized the leaching. FTIR spectra of these samples indicate that a substantial portion of the dendrimer amide bonds was removed by solution activation (note the small y-axis value in Figure 4 relative... 

Dendrimer thermolysis, i.e., the removal of the dendrimer component via exposure to high temperatures in oxidative, reducing, or neutral gas-phase environments, is the technique that has been so far exclusively employed for this task. Other potential low-temperature removal methods, such as chemical leaching of the dendrimCT or treatment under plasma conditions, have been suggested but not demonstrated experimentally. 

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