Four tethered titanocene complexes were covalently immobilized onto 3-mercaptopropyl-functionalized silica gel. We have investigated the influence of the length of the tether and of the ansa-bridge on the activity in the heterogeneous hydrosilylation of the cyclic imine 2-phenylpyrroline, taken as an illustrative example. Possible metal leaching during the reaction was investigated using ICP/OES, recycling studies and the three-phase test. The novel immobilized catalysts exhibit an activity similar to their homogeneous analogues in the tested hydrosilylation reactions with a TOF of ∼20 h−1. Furthermore, our results indicate that metal leaching is negligible under the applied reaction conditions.
四个由缚酸剂连接的
二茂铁基配合物通过共价键固定在3-巯丙基功能化的
硅胶上。我们研究了缚酸剂长度和ansa桥对环状
亚胺2-苯基
吡咯啉非均相加氢
硅烷化反应活性的影响,以作为示例。在反应过程中可能发生的
金属浸出现象,我们通过ICP/OES、循环实验和三相测试进行了探究。这些新型固定化催化剂在测试的加氢
硅烷化反应中展现出与均相催化剂类似的活性,其转化频率(TOF)约为20 h−1。此外,我们的结果表明,在所应用的反应条件下,
金属泄漏可以忽略不计。