Cleavage of siloxane bonds (Si-O) in organosiloxanes (OSs) is one of the most fundamentally and practically important challenges in the modern chemistry of silicones. However, no benign approaches have been found to cleave these bonds under mild conditions. In this paper, siloxane bond cleavage in polydimethylsiloxane (PDMS) was studied using a mixture of the “green” reagent dimethyl carbonate (DMC) and an environmentally benign reagent, tris(pentafluorophenyl)borane (B(C6F5)3). The obtained results indicate that the Si-O bonds are cleaved by reaction with DMC to form lower-weight polymer fragments with alkoxy end groups, while the addition of B(C6F5)3 to the depolymerizing mixture significantly increases the degree of PDMS depolymerization at room temperature or with increasing temperature. Quantum chemical calculations show that the DMC molecules form stable complexes with B(C6F5)3 by preferable formation of C=O····B bonds, which increases the solvation effects and kinetic energy upon collision with PDMS. This result provides an appropriate electronic structure and orientation for the complexes for more effective interaction with Si-O-Si via a concert mechanism. This proposed benign approach can be used for the production of new OS polymers, silicone recycling and functionalization of metal or metalloid oxides. We report a novel approach of siloxane bond splitting in organosiloxane using mixture of tris(pentafluorophenyl)borane and dimethyl carbonate. In the first part of this note, depolymerization of polydimethylsiloxane by dimethyl carbonate and with the addition of tris(pentafluorophenyl)borane is studied. Reactions are studied at different concentrations of above-mentioned reagents and temperature while the second part of this note represents theoretical calculation results which explain the mechanism of the depolymerization reaction.

中文翻译：

---

三（五氟苯基）硼烷和碳酸二甲酯的中间体为更深层次的有机硅氧烷解聚反应铺平了道路

有机硅氧烷 (OS) 中硅氧烷键 (Si-O) 的断裂是现代有机硅化学中最基本和最重要的挑战之一。然而，尚未发现在温和条件下裂解这些键的良性方法。在本文中，使用“绿色”试剂碳酸二甲酯 (DMC) 和环境友好试剂三（五氟苯基）硼烷 (B(C6F5)3) 的混合物研究了聚二甲基硅氧烷 (PDMS) 中的硅氧烷键断裂。所得结果表明，Si-O 键通过与 DMC 反应断裂，形成具有烷氧基端基的重量较轻的聚合物片段，而在解聚混合物中加入 B(C6F5)3 显着提高了室温下 PDMS 的解聚程度。温度或随着温度升高。量子化学计算表明，DMC分子通过优先形成C=O····B键与B(C6F5)3形成稳定的配合物，增加了与PDMS碰撞时的溶剂化效应和动能。该结果为配合物提供了合适的电子结构和取向，以便通过协同机制与 Si-O-Si 更有效地相互作用。这种提议的良性方法可用于生产新的 OS 聚合物、有机硅回收和金属或准金属氧化物的功能化。我们报告了一种使用三（五氟苯基）硼烷和碳酸二甲酯的混合物在有机硅氧烷中分裂硅氧烷键的新方法。在本说明的第一部分，研究了通过碳酸二甲酯和添加三（五氟苯基）硼烷对聚二甲基硅氧烷的解聚。