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Zn4@POSS-1
POSS catalyst
For the first time, multifunctional imine-POSS-based metal complex was synthesized and structurally characterized. Zn4@POSS-1 was obtained in high yields via simultaneous complexation reaction of imine functionalized silsesquioxane with Zn(II) salts under mild conditions. Zn4@POSS-1 was successfully tested in the cycloaddition of CO2 with terminal epoxides, with tetrabutylammonium iodide as a co-catalyst, which ensured a high activity and selectivity of the tested catalytic system. Styrene oxide, which is usually a challenging substrate, was converted under mild conditions (1 atm CO2) and with a short reaction time (4 h) into the corresponding cyclic carbonate, in high yield (96%). For terminal epoxides, high yields (85–99%) of cyclic carbonates were achieved under mild conditions, illustrating that this catalytic system was effective with both alkyl and aryl epoxides while tolerating functionalities including halides and ethers.
See: Chemistry - A European Journal, 2020, doi.org/10.1002/chem.202002996
Amide-POSS
Homosubstituted amido-functionalized polyocta-hedral oligomeric silsesquioxanes (POSS) have been synthe-sized by using acyl chlorides in high yields (ca. 95 %). The functionalized silsesquioxanes with bulky organic side-chains attached to cubic siloxane core form spherical-like, well-separated nano-particles with a size of approximately 5 nm. Amide-POSS were extensively studied by TG and DTA techniques in flowing nitrogen and synthetic air atmospheres. Experiments were performed in the 30–1000 °C range and showed different behavior depending on the atmosphere. The residual masses obtained at different temperatures were analyzed using IR to get insight into the thermal degradation mechanism. Additionally, activation energies of the decomposition process using Kissinger method were calculated.
See: Chemistry - A European Journal, 2014, 20, 15966-15974.; RSC Advances, 2015, 5, 72340-72351.; Journal of Organometallic Chemistry, 2017, 847, 173-183.
Cage-Rearrangement
Reorganization of the siloxane cage-like core (T8 → T10) can be easily performed, including isolation of intermediates, and cage rearrangement achieved by using superacid CF3SO3H (TfOH). Moreover, T10-like SQs can be obtained in a one-step reaction by alkoxysilane condensation in trifluoromethanesulfonic acid conditions.
See: RSC Advances 2016, 6, 66037-66047; RSC Advances 2015, 5, 72340-72351; Chemistry - A European Journal 2014, 20, 15966-15974.
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