| Research Abstract |
1. Synthesis of novel silanols.
Following novel silanols were prepared, isolated, and their structures were determined ; Silanetriols, RSi(OH)_3, Disiloxanetetraols, (RSi(OH)_2O)_2 (R=i-Pr, Mes, Tip, cyclohexyl) ; Cyclotetrasiloxanetetraol, (i-PrSi(OH)O)_4 (all four isomers) ; Incompletely condensed silsesquioxanes, T_3(OH)_3, T_4(OH)_2, and T_5(OH).
2. Supramolecular aggregates composed of silanols.
Co-crystallization or recrystallization from mixed solvent gave novel hydrogen-bonded supramolecular aggregates : all-cis-(i-PrSi(OH))_4 and i-Pr_2Si(OH)_2, cis,trans-(TipSi(OH)O)_3 from MeOH/THF, cis,trans,cis-(i- PrSi(OH)O)_4, cis, trans, cis-(i-PrSi(OH)O)_4.
3. Synthesis of polycyclic laddersiloxanes.
By applying our new method (stepwise construction of laddersiloxanes), the first functionalized tricyclic laddersiloxanes and pentacyclic laddersiloxane were synthesized. The structures of the Tetraphenyl and tetrahydroxyl tricyclic laddersiloxanes, and pentacyclic laddersiloxane were determined by X-ray crystallography. In addition, reaction with separated diastereomer made it possible to construct first heptcyclic and nonacyclic laddersiloxanes.
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