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solution-phase TEMPO catalyst 1 (Table 1, entry B). The small Conflicts of interest
activity exhibited by the TEMPO-based isotropic resin is likely
explained by the presence of a small amount of surface-
There are no conflicts to declare.
accessible catalyst sites, a phenomenon observed in isotropic
control resin studies of prior catalytic LLC polymer systems.16
Notes and references
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The activity and substrate selectivity of the TEMPO-based
resin catalysts were also compared to two commercial TEMPO-
based solid-state catalysts: microporous silica-supported TEMPO
(Siliacats brand, referred to herein as SiO2-TEMPO) and amor-
phous polystyrene-supported TEMPO (PS-TEMPO). Under
the same reaction conditions (as described previously), the
TEMPO-based HII catalyst was more active and more substrate
size-selective than both commercial solid catalysts (Fig. 3e and f
and Table 1 entries E & F). The relatively poor activity of
PS-TEMPO is likely due to its amorphous, non-porous/dense
nature;31 whereas the moderate activity and substrate size selec-
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and Technology Center (project 16-3, funded by the Defense
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12056 | Chem. Commun., 2018, 54, 12053--12056
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