Metal-organic frameworks (MOFs) have achieved great success in the field of heterogeneous catalysis, however, it’s still challenging to design MOF catalysts with enhanced selectivity. Here, we demonstrated a combination strategy of metal design and ligand design on the enantioselectivity—that is the enantioselectivities of chiral MOF (CMOF) catalysts could be significantly enhanced by the rational choice of metal ions with higher electronegativities and introducing sterically demanding groups into the ligands. Four isostructural Ca-, Sr- and Zn-based CMOFs were prepared from enantiopure phosphono-carboxylate ligands of 1,1′-biphenol that are functionalized with 2,4,6-trimethyl- and 2,4,6-trifluoro-phenyl groups at the 3,3’-position. The uniformly distributed metal phosphonates along the channels could act as Lewis acids and catalyze the asymmetric transfer hydrogenation of heteroaromatic imines (benzoxazines and quinolines). Particularly, the Ca-based MOF 1 with 2,4,6-trimethyl groups at the substituents exhibited enhanced catalytic performance, affording the highest enantioselectivity (up to 97%). It is also the first report of the heterogeneous catalyst with chiral non-noble metal phosphonate active sites for asymmetric transfer hydrogenation reactions with Hantzsch ester as the hydrogen source. The catalyst design strategy demonstrated here is expected to develop new types of chiral materials for asymmetric catalysis and other chiral applications.

金属有机骨架（MOF）在非均相催化领域取得了巨大的成功，然而，设计具有更高选择性的MOF催化剂仍然具有挑战性。在这里，我们展示了对映选择性的金属设计和配体设计的组合策略-也就是说，通过合理选择具有更高电负性的金属离子并将空间上需要的基团引入配体中，可以大大提高手性MOF（CMOF）催化剂的对映选择性。从对映体纯的1,1'-双酚膦酰基羧酸酯配体制备了四个基于Ca，Sr和Zn的CMOF，这些配体被2,4,6-三甲基和2,4,6-三氟苯基官能化在3,3'位置。沿通道均匀分布的金属膦酸酯可充当路易斯酸并催化杂芳族亚胺（苯并恶嗪和喹啉）的不对称转移氢化。特别地，在取代基上具有2,4,6-三甲基的Ca基MOF 1表现出增强的催化性能，提供最高的对映选择性（至多97％）。这也是具有手性非贵金属膦酸酯活性位点的非均相催化剂的首次报道，该非均相催化剂具有以汉茨tz酸酯为氢源的不对称转移氢化反应。此处展示的催化剂设计策略有望开发出用于不对称催化和其他手性应用的新型手性材料。取代基上的6-三甲基表现出增强的催化性能，提供最高的对映选择性（最高97％）。这也是具有手性非贵金属膦酸酯活性位点的非均相催化剂的首次报道，该非均相催化剂具有以汉茨tz酸酯为氢源的不对称转移氢化反应。此处展示的催化剂设计策略有望开发出用于不对称催化和其他手性应用的新型手性材料。取代基上的6-三甲基表现出增强的催化性能，提供最高的对映选择性（最高97％）。这也是具有手性非贵金属膦酸酯活性位点的非均相催化剂的首次报道，该非均相催化剂具有以汉茨tz酸酯为氢源的不对称转移氢化反应。此处展示的催化剂设计策略有望开发出用于不对称催化和其他手性应用的新型手性材料。