Oligosilanes as Silyl Radical Precursors through Oxidative Si−Si Bond Cleavage Using Redox Catalysis

Abstract

Oligosilanes are of great interest in the fields of organic photonics and electronics. In this communication, a highly efficient visible‐light‐mediated hydrosilylation of electron‐deficient alkenes through cleavage of a trimethylsilyl‐polysilanyl Si−Si bond is explored. These reactions smoothly occur on readily available organo(tristrimethylsilyl)silanes and other oligosilanes in the presence of an IrIII‐based photo‐redox catalyst under visible light irradiation. Silyl radicals are generated through single electron oxidation of the oligosilane assisted by the solvent. The introduced method exhibits broad substrate scope and high functional group tolerance with respect to the organo(tristrimethylsilyl)silane and alkene components, enabling the construction of functionalized trisilanes. In addition, this catalytic system can be also applied to highly strained bicyclo[1.1.0]butanes as silyl radical acceptors.

Transforming a Fluorochrome to an Efficient Photocatalyst for Oxidative Hydroxylation: A Supramolecular Dimerization Strategy Based on Host‐Enhanced Charge Transfer

“…Bohan Tang, Weiquan Xu, Jiang-Fei Xu,* and Xi Zhang* Abstract: The development of non-covalent synthetic strategy to fabricate efficient photocatalysts is of great importance in theranostic and organic materials. Herein, a fluorochrome N,N'-dimethyl 2,5-bis(4-pyridinium)thiazolo [5,4-d]thiazolediiodide (MPT) was transformed into an efficient photocatalyst through supramolecular dimerization in the cavity of cucurbit [8]uril (CB [8]). The host-enhanced charge transfer interaction within the supramolecular dimer 2MPT-CB [8] dramatically promoted intersystem crossing to produce triplet.…”

“…The host-enhanced charge transfer interaction within the supramolecular dimer 2MPT-CB [8] dramatically promoted intersystem crossing to produce triplet. In addition, the staggered conformation of 2MPT-CB [8] facilitated the energy transfer and electron transfer of the triplet. As a result, 2MPT-CB [8] could serve as a highefficiency photocatalyst for the oxidative hydroxylation of arylboronic acids.…”

“…In addition, the staggered conformation of 2MPT-CB [8] facilitated the energy transfer and electron transfer of the triplet. As a result, 2MPT-CB [8] could serve as a highefficiency photocatalyst for the oxidative hydroxylation of arylboronic acids. This supramolecular dimerization strategy enriches the supramolecular engineering of functional psystems.…”

“…The development of efficient photosensitizers and photocatalysts is of great importance in theranostic and organic materials. [1][2][3][4][5][6][7][8] To design a photosensitizer or photocatalyst, there are two key points: 1) high-efficiency intersystem crossing (ISC) to generate long-lived triplet state, and 2) high-efficiency energy transfer or electron transfer to conduct photochemical reactions. [9][10][11][12][13][14] To fabricate efficient photosensitizers and photocatalysts through non-covalent synthesis is drawing increasing interests for its convenient construction manners beyond molecular level.…”

“…[41][42][43][44][45][46][47][48][49][50][51][52][53][54] To this end, N,Ndimethyl 2,5-bis(4-pyridinium)thiazolo [5,4-d]thiazole diiodide (MPT), an efficient fluorochrome with acceptor-donoracceptor structure, was designed. [55] As shown in Scheme 1, it self-assembled into supramolecular dimer in the cavity of cucurbit [8]uril (CB [8]) in a parallel and staggered conformation. [56] Such a conformation could strengthen the charge transfer interaction and facilitate the contact with other reactants.…”