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Synthesis, Structures, and Thermal Properties of Symmetric and Janus “Lantern Cage” Siloxanes

2018; Wiley; Volume: 25; Issue: 7 Linguagem: Inglês

10.1002/chem.201805200

1521-3765

Taishi Uchida, Yasunobu Egawa, Takuto Adachi, Naoki Oguri, Masato Kobayashi, Takako Kudo, Nobuhiro Takeda, Masafumi Unno, Ryoji Tanaka,

Supramolecular Chemistry and Complexes

Abstract Symmetric and asymmetric (Janus‐type) new “lantern cage” siloxanes (PhSiO 1.5 ) 4 (Me 2 SiO) 4 (RSiO 1.5 ) 4 (R=Ph or i Bu) were synthesized through reaction of all‐ cis ‐[PhSi(OSiMe 2 Br)O] 4 with all‐ cis ‐[RSi(OH)O] 4 (R=Ph or i Bu). These precursors were obtained by facile two or three‐step reactions from commercially available compounds. The spectroscopic properties of the resulting products were fully characterized and they showed high thermal stability and sublimation without decomposition. The crystal structures clearly indicated that the internal vacancy volumes of the lantern cages are considerably larger than that of octaphenylsilsesquioxane (PhSiO 1.5 ) 8 . DFT calculations of the lantern cage showed a distinctly different electronic state from that of octasilsesquioxane. These results suggest that lantern cage siloxanes have a characteristic “field” in the molecule.