GENEALOGICALLY DIRECTED SYNTHESES (POLYMERIZATIONS) - DIRECT EVIDENCE BY ELECTROSPRAY MASS-SPECTROSCOPY

From a synthetic perspective, divergent dendrimer syntheses are often presented as idealized hyperbranched growth processes leading to perfect dendritic structures. Experimentally it has been found that in addition to ideal structures, varying amounts of structural errors are produced at each growth stage (generation). These defects (mutants) are created as a function of processing conditions and generation specific steric effects. This investigation focused on the divergent synthesis of Starburst(R) polyamidoamine dendrimers** and the use of electrospray mass spectroscopy for appraising ideal structure/defect ratios as a function of generation. With this methodology, initial defect types and so called ''defect propagation chains'' have been identified and characterized. These hyperbranched mutation (defect) patterns provide ample evidence for the ''genealogically directed'' character of this divergent polymerization strategy.