Acceleration of an aminolysis reaction using a PAMAM dendrimer with 64 terminal amine groups

Exploiting dense shell/packing principles to invoke stereoselectivity in a reaction accelerated by a chiral dendrimer

“…The reactions were carried out in the same way, except that a 0.4 mM solution of L-phenyl terminated dendrimer 2 was used (giving the same 6.4 mM amine concentration used in the controls). 6,7 As with the previous work, the rate accelerations are attributed to the static micellar structure of the dendrimer and the increased solubility of the substrates within the hydrophobic external layer. If we look at the dendrimer data in more detail and compare the rates to those obtained for the control reactions, we observe relative rate accelerations of 101.9 and 163.7 for the D and the L substrates respectively (when compared to the slowest control reaction), Table 1.…”

“…1 A second approach attempts to mimic the encapsulation behaviour of enzymes using larger polymeric molecules. 6 As part of this study we noticed that the size of the dendrimer had a significant effect on the rate of reaction. As well as providing specific internal environments, these bulk molecules are often very soluble in water.…”

“…[6][7][8] Our first control experiment simply measured the background reaction of the substrates in buffer (6.0 Â 10 À5 M solution of substrate 4 or 5 in 0.1 M, pH 8.5 Tris). For all reactions, p-nitrophenolate is liberated during aminolysis, 13 which is UV active and enables the concentration of product to be calculated using UV spectrophotometry (by following the increase in the signal intensity at 410 nm).…”

Preparation and thermal stability of new cellulose‐based poly(propylene imine) and poly(amido amine) hyperbranched derivatives

“…These dendrimers, as such or their modified derivatives, have been the subject of many intensive studies as promising materials for potential applications in a variety of fields. For examples, PAMAM and its modified derivatives have been used in catalysis,33, 34 gene delivery,35, 36 drug delivery,37, 38 biochemical,39 biophysical,40–42 medicinal,43 hydorgel,44 biocompatible materials,45 and selective heavy metal ions removal 46. Metal‐containing PPI were found to have catalytic, electronic, and magnetic properties 47–50…”

Catalysis by Self-Assembled Structures in Emergent Reaction Networks

“…Micellar catalysis is very general and happens with many kinds of self-assembling materials besides amphiphiles. Examples include polymerized and polymeric amphiphiles [24] and dendrimers [7,23]. Dendrimers are spherical macromolecules that are somewhat similar to micelles, except that while micelles are rather fluid aggregations composed of many amphiphilic molecules held together by the hydrophobic effect, dendrimers are single static structures tightly held together by covalent bonds.…”