Photo Lewis acid generators: photorelease of B(C₆F₅)₃ and applications to catalysis

Abstract

A series of molecules capable of releasing of the strong organometallic Lewis acid B(C6F5)3 upon exposure to 254 nm light have been developed.

Preparation of Cellular Silicone Elastomers Using Epoxide-Functionalized Silicones

“…To control the catalytic activity of B­(C 6 F 5 ) 3 , Khalimon et al reported a series of photo Lewis acid generators that release B­(C 6 F 5 ) 3 only upon UV irradiation . Frustrated Lewis pairs that decompose and release free B­(C 6 F 5 ) 3 upon mild heating have been synthesized .…”

“…To control the catalytic activity of B(C 6 F 5 ) 3 , Khalimon et al reported a series of photo Lewis acid generators that release B(C 6 F 5 ) 3 only upon UV irradiation. 43 Frustrated Lewis pairs that decompose and release free B(C 6 F 5 ) 3 upon mild heating have been synthesized. 44 Since B(C 6 F 5 ) 3 -catalyzed SiH derivatization begins with polarization of the Si−H bond through complexation between the hydride and the boron center, 25 a more economical and facile method to control the activity of B(C 6 F 5 ) 3 may be to form a reversible adduct with the Lewis base.…”

Coupling agents with 2,4,6,8-tetramethylcyclotetrasiloxane core – synthesis and application in styrene–butadiene rubber production

“…They might be regarded as silicon analogs of crown ethers, since they form different-sized rings of alternating silicon and oxygen atoms, with various side chains (R = hydrogen atoms, alkyl, or vinyl groups) attached to silicon. 12 These compounds are characterized by flexibility, high strength of Si-O bonds, and high reactivity under specified conditions in miscellaneous organic reactions, i.e., hydrolysis, 13 halogenation, 14 dehydrogenative couplings, 15,16 silylative coupling, 17,18 alkylative cleavage, 19 Piers-Rubinsztajn reaction, 20 ring-opening polymerizations, 21,22 and hydrosilylation. [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] 8-Membered compounds such as DH 4 , because of the possible modification of peripheral Si-H groups by a hydrosilylation reaction, have opened access to several functional materials.…”

“…12 These compounds are characterized by flexibility, high strength of Si–O bonds, and high reactivity under specified conditions in miscellaneous organic reactions, i.e. , hydrolysis, 13 halogenation, 14 dehydrogenative couplings, 15,16 silylative coupling, 17,18 alkylative cleavage, 19 Piers–Rubinsztajn reaction, 20 ring-opening polymerizations, 21,22 and hydrosilylation. 23–39 8-Membered compounds such as DH 4 , because of the possible modification of peripheral Si–H groups by a hydrosilylation reaction, have opened access to several functional materials.…”

Remote Stereochemistry of a Frustrated Lewis Pair Provides Thermal and Photochemical Control of Reactivity

“…For example, Hoshimoto, Ogoshi and co-workers described that the combination of a phosphine-oxide derived carbene and B­(C 6 F 5 ) 3 form a classical Lewis adduct at room temperature, but this system can be thermally stimulated to react with H 2 via the corresponding FLP . The notion of photoinitiation of FLP chemistry has not been explored, although Piers and co-workers synthesized a “photo Lewis acid generator” that affords B­(C 6 F 5 ) 3 on irradiation . Furthermore, Ozin described an FLP-type reduction of CO 2 on the surface of In 2 O 3– x (OH) y , which was more effective in the light …”