表面功能化聚合物固载钯催化剂的制备及其催化苯甲醛邻位碳氢键官能团化的性能研究

Heterogenization of homogeneous transition metal catalyst, bearing important application value, not only favors the efficient separation and recycling of the expensive catalyst, but affords unique regio- and stereo-selectivities compared with its homogeneous counterpart. The present program plans to carry out the diverse surface-functionalizations on the backbone of poly(4-vinylphenol) to immobilize the Pd(II). A series of polar chains would be introduced on polymer to improve the steric and electronic configuration nearby the catalytically active metal sites, and to accelerate the gathering of polar reactants on the catalyst to improve the accessibility of catalytically active centres. We also plan to import the bidentate amino acids to immobilize the Pd(II), aiming to enhance the heterogenization and thus improve the recyclability. In the immobilized-Pd(II) catalyzed ortho-C(sp2)–H functionalization of benzaldehydes, bidendate amino acids, also playing as transient directing group, can be simultaneously coordinated with immobilized-Pd(II) and benzaldehyde to establish a close connection between catalytic centres and reactants. The proceeding of the present program will be beneficial for the interpretation of influencing factors on the catalytic performance of heterogenized homogenous catalyst from steric and electronic configuration aspect. Moreover, the relationship between catalyst structure and performance can be established.

均相过渡金属催化剂的固载化既可以实现昂贵催化剂的分离和回收，也可获得迥异于均相催化剂的区域选择性和立体选择性，具有重要的应用价值。本项目拟以聚(4-乙烯基苯酚)为载体，通过对聚合物进行表面功能化修饰来实现Pd(II)的固载化。通过向聚合物表面引入极性基团链，优化Pd活性中心周围的空间和电子构型，并促进极性反应物在催化剂上的聚集，提高催化活性位的可接近度。通过引入双齿配体氨基酸来与Pd(II)配位，提高固载强度，改善回收重复利用率；在固载化Pd(II)催化的苯甲醛邻位C(sp2)–H键直接官能团化反应中，双配位氨基酸也作为临时导向基团，通过配位关联起固载化的Pd与反应底物，促进反应的进行。该项目的开展有助于我们从空间构型和电子效应方面来解释固载化催化剂催化性能的影响因素，并构建起催化剂结构与性能之间的关联

碳氢键官能团化是构建药物分子的重要策略，而均相的过渡金属催化剂是完成此类反应的最高效催化剂，但是由此带来的催化剂从产品中的分离以及回收利用等问题严重制约着均相催化剂在工业中的广泛应用。均相过渡金属催化剂的固载化既可以实现分离回收，也可获得迥异于均相催化剂的区域选择性和立体选择性，具有重要的应用价值。本课题主要研究内容包括钯金属催化剂在碳氢键官能团化中的应用研究和钯金属在聚合物表面上的固载及催化性能研究。