Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Angew Chem Int Ed Engl. 2023 Jan 26;62(5):e202214267. doi: 10.1002/anie.202214267. Epub 2022 Dec 22.
Functionalizing inorganic particles with organic ligands is a common technique for heterogenizing organometallic catalysts. We describe how coordinating molecular platinum to silica nanoparticles functionalized with a high density of norbornene ligands causes unexpected latency of the catalytic activity in hydrosilylation reactions when compared to an identical reaction in which the norbornene is not tethered (2 % vs 97 % conversion in 1 h). Performing the hydrosilylation at elevated temperature (70 °C) suppresses this activity delay, suggesting the usefulness of this technique towards temperature-triggered catalysis. We demonstrate that this latency is related to ligand density on the particle surface, chemical structure of the norbornene, and silica nanoparticle topology. We also establish the benefit of this latency for triggered curing of silicone elastomers. Overall, our work establishes the non-innocent role of inorganic supports when functionalized with organometallic complexes.
用有机配体功能化无机颗粒是实现有机金属催化剂多相化的常用技术。我们描述了如何将配位分子铂与高密度降冰片烯配体功能化的二氧化硅纳米颗粒配位，与未键合的降冰片烯（1 h 内转化率分别为 2%和 97%）相比，在硅氢加成反应中会导致催化活性出现意外的迟滞。在升高的温度（70°C）下进行硅氢加成反应会抑制这种活性延迟，表明该技术在温度触发催化方面具有应用潜力。我们证明这种迟滞与颗粒表面配体密度、降冰片烯的化学结构和二氧化硅纳米颗粒拓扑结构有关。我们还确定了这种迟滞对于硅酮弹性体触发固化的益处。总的来说，我们的工作确立了功能化的无机载体在与金属有机配合物配位时所扮演的非惰性角色。
