Tamura Masazumi, Kishi Ryota, Nakagawa Yoshinao, Tomishige Keiichi
Graduate School of Engineering, Tohoku University, Aoba 6-6-07, Aramaki, Aoba-ku, Sendai 980-8579, Japan.
Nat Commun. 2015 Oct 5;6:8580. doi: 10.1038/ncomms9580.
Multidentate materials formed by simply mixing heterogeneous and homogeneous components are promising for construction of versatile active sites on the surface of heterogeneous compounds, however, to the best of our knowledge, there are no reports on such materials. Self-assembly of hetero-hybrid catalytic materials occurs when heterogeneous catalysts having adjacent Lewis acid-Lewis base sites are mixed with an organic modifier that contains at least two Lewis base functional groups. Here we demonstrate the strategy by combining cerium oxide and 2-cyanopyridine that self-assembles to form a charge-transfer complex in methanol that exhibits a 2,000-fold increase in reaction rate for hydromethoxylation of acrylonitrile with high selectivity compared with cerium oxide or 2-cyanopyridine alone. The catalytic system is applied to the transesterification and Knoevenagel condensation affording 14-fold and 11-fold higher activity, respectively, than cerium oxide alone. These results demonstrate the potential versatility of the catalytic system and the generality of the catalyst preparation strategy.
通过简单混合非均相和均相成分形成的多齿材料有望在非均相化合物表面构建多功能活性位点，然而，据我们所知，尚无关于此类材料的报道。当具有相邻路易斯酸 - 路易斯碱位点的非均相催化剂与含有至少两个路易斯碱官能团的有机改性剂混合时，会发生杂化催化材料的自组装。在此，我们展示了一种策略，即将氧化铈和2 - 氰基吡啶组合，它们在甲醇中自组装形成电荷转移络合物，与单独的氧化铈或2 - 氰基吡啶相比，该络合物对丙烯腈氢甲氧基化反应的速率提高了2000倍，且具有高选择性。该催化体系应用于酯交换反应和Knoevenagel缩合反应时，活性分别比单独的氧化铈高14倍和11倍。这些结果证明了该催化体系的潜在多功能性以及催化剂制备策略的通用性。
