Direct cross-linking of silyl-functionalized cage siloxanes via nonhydrolytic siloxane bond formation for preparing nanoporous materials

Miharu Kikuchi; Taiki Hayashi; Takamichi Matsuno; Kazuyuki Kuroda; Atsushi Shimojima

doi:10.1039/d4dt00215f

Direct cross-linking of silyl-functionalized cage siloxanes via nonhydrolytic siloxane bond formation for preparing nanoporous materials

Dalton Trans. 2024 Apr 2;53(14):6256-6263. doi: 10.1039/d4dt00215f.

Authors

Miharu Kikuchi¹, Taiki Hayashi¹, Takamichi Matsuno^{1

2

3}, Kazuyuki Kuroda^{1

2}, Atsushi Shimojima^{1

2

3}

Affiliations

¹ Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan. shimojima@waseda.jp.
² Kagami Memorial Research Institute for Materials Science and Technology, Waseda University, 2-8-26 Nishiwaseda, Shinjuku-ku, Tokyo 169-0051, Japan.
³ Waseda Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.

PMID: 38501342
DOI: 10.1039/d4dt00215f

Abstract

Bottom-up synthesis of siloxane-based nanoporous materials from siloxane oligomers is promising for constructing well-defined structures at a molecular level. Herein, we report the synthesis of nanoporous materials consisting of cage-type siloxanes through the nonhydrolytic siloxane bond formation reaction. Cage siloxanes with double-n-ring geometries (n = 4 or 6) modified with dimethylsilyl and dimethylethoxysilyl groups are synthesized and directly cross-linked using a B(C₆F₅)₃ catalyst, resulting in the formation of porous networks composed of alternating cage siloxane nodes and tetramethyldisiloxane (-SiMe₂OSiMe₂-) linkers. Compared with conventional hydrolysis and polycondensation reactions of alkoxysilyl-modified cage siloxanes under acid conditions, the non-hydrolytic condensation reaction was found favorable for the formation of porous siloxane networks without unwanted cleavage of the siloxane bonds.