Immobilization
of metalloporphyrin onto a solid support is highly
desirable in the chemical industry. Herein, we reported for the first
time the efficient immobilization of cationic zincporphyrin complexes
on mesoporous SBA-15 by a simple one-pot method by refluxing 5,10,15,20-tetrakis(4-pyridyl)porphyrin
zinc(II) (Zn-TPy), SBA-15, and 3-(trimethoxysilyl)propyl bromide in
toluene, DMF, NMP, or THF. Studies suggest that solid catalyst with
high Zn content, stiochiometric Br–/Zn ratio, and
uniform distribution of active sites could be obtained using DMF as
the solvent, possibly related to its suitable polarity. The bifunctional
solid material with both Lewis acid site and nucleophile acts as an
efficient catalyst for catalyzing cycloaddition of CO2 and
epoxides under cocatalyst free conditions. Compared with the homogeneous
counterpart, the solid catalyst is more active (TOF = 1686 h–1 versus 370 h–1). This suggests that the closely
connected Lewis acid and Br– in the solid material
could enhance their cooperation during the catalytic process. This
work provides an efficient method for the synthesis of bifunctional
solid catalyst exhibiting enhanced cooperation activation effect for
the CO2 cycloaddition reaction.
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