The effect of size on the rate of an aminolysis reaction using a series of amine terminated PAMAM dendrimers

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.…”

“…2,3 This approach enables careful control of internal functionality and more importantly, internal environment. 7 This was due to the specific encapsulation mechanism of the accelerated reaction, 8 which involves hydrophobic binding of the substrate within the outer steric layer of the dendrimer. 4 Many types and classes of polymers that have been used to mimic enzyme behaviour.…”

“…7,8 Peripheral functionalization of the DAB dendrimer with L-phenylalanine was performed in two steps as shown in Scheme 1. Although this is smaller than the optimum dendrimer used in our previous work, the addition of 16 amino acids adds another layer to the periphery of the dendrimer; in effect converting it to the 3rd generation.…”

“…[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…”