二维（2D）异金属有机框架（HMOF）是由异种金属通过有机配体连接形成的多孔二维材料。作为一种特殊金属有机框架（MOF），它在催化、气体分离等方面展现出广阔应用前景，也为分子磁学研究提供了重要材料平台。异金属的加入使材料的设计更灵活，为新性质的涌现、多功能的耦合提供可能，但也为结构的精准制备增加了难度，其中单层有序2D HMOF的制备尤其具有挑战性。表面在位配位化学方法在同金属2D MOF的制备中取得了成功，但用于制备有序2D HMOF时则受限于缺乏调控异金属配位选择性的有效手段。本项目拟通过两个方案解决这一问题、实现有序2D HMOF的可控表面在位构筑：①多官能团配体与不同金属的分级配位；②同金属双节点2D MOF的选择性金属置换。利用扫描隧道显微镜及谱学原位表征所得2D HMOF的自旋性质，探索异金属的加入及组成对体系自旋性质的影响。本项目的开展将有助于异金属有机磁性材料和器件的开发。

Two-dimensional (2D) heterometal-organic frameworks (HMOFs) are porous 2D materials constructed by metals of different types connected via organic ligands. As a subfamily of 2D metal-organic frameworks (MOFs), 2D HMOFs hold potential for various applications such as catalysis, gas separation, etc. Moreover, they provide a material basis for molecular magnetism. The addition of heterometals in MOFs introduces more flexibility in material designing, which might lead to the emergence of new properties as well as the multi-functionalization of the materials. However, the introduction of heterometals also brings challenges to the material preparation, especially the fabrication of the 2D HMOFs with atomic thickness in which heterometal atoms are orderly arranged. On-surface coordination chemistry, an efficient bottom-up approach to preparing well-defined low-dimensional metal-organic nanostructures, has succeeded in fabrication of various monolayer 2D MOFs with homogeneous metal atoms as coordination centers. However, its application in the preparation of well-ordered 2D HMOFs is subject to the few methods for efficiently tuning the selectivity of the on-surface coordination of different metals. To solve this problem, two scenarios are proposed in this project, so as to achieve the controlled on-surface construction of ordered 2D HMOFs: (1) hierarchical coordination of multi-functionalized molecular ligands with different metals, and (2) selective metal substitution of the homometallic binodal 2D MOFs. With the aid of scanning tunneling microscopy and spectroscopy, we will investigate the spintronic properties of the so-achieved ordered 2D HMOF structures, and explore the effect of heterometals in tuning the spintronic properties of metal-organic systems. These studies may inspire the development of heterometal-organic magnetic materials and devices.