Assembly Of Two Examples Of Chiral Crystalline Porous Materials Based On C-metal Bonds And Their Heterogeneous Asymmetric Catalytic Properties

Compared with the conventional metal-organic frameworks（MOFs）driven by metal heteroatoms,metal-carbon bond-driven organometallic frameworks（OMFs）,which are self-assembled by metal nodes and organic ligands,are rarely studied,especially chiral OMFs（COMFs）are more rarely reported.Organometallic framework materials OMFs,as an emerging subset of MOFs,are a new direction in metal-organic chemistry and deserve further academic exploration and research.Isonitrile is a typical organic carbon ligand with goodσ-giving electron interaction and stableπ-anti-bonding during coordination with transition metals,and is an ideal type of organic carbon ligand for building framework materials for OMFs.Unlike conventional MOFs with heteroatomic coordination groups,the ligated isonitrile can be further functionalized,for example,by metal-mediated nucleophilic addition to generate non-cyclic azacyclic carbines（ADCs）.In recent years,ADCs as an alternative to mainstream N-heterocyclic carbenes（NHCs）can provide strongerσ-electrons for transition metals with better spatial tunability,allowing the preparation of metal catalysts with richer electronic and structural features.The combination of the advantages of organometallic frameworks（OMFs）and covalent organic frameworks（COFs）can lead to new opportunities for the design of advanced materials with high tunability and functionality.Covalent organic frameworks（COFs）are porous crystalline materials with periodically extended structures.They are highly stable,have large surface areas,tunable pore sizes,and especially have stably ordered chiral spaces,showing outstanding ability in the field of asymmetric catalysis.Although a large number of COFs have been reported,the preparation of chiral COFs is scarce in comparison.The synthesis of stable framework materials of chiral COFs and their application in asymmetric catalysis remains the main challenge at present.To date,CCOFs synthesized by the chiral backbone monomer approach have a clear structure and a precise and uniform distribution of chiral sites,and thus this approach is more commonly used than post-synthesis,chiral post-modification and chiral catalytic synthesis,but the synthesis of CCOFs from chiral backbone monomers remains a serious challenge.Ⅰ.Constructed single chiral Pd-ADC-derived chiral COMFs based on OMFs materials obtained by assembling Pd I₂with tridentate isonitrile compounds by post-synthetic modification（PSM）with optically pure secondary amines,taking advantage of the inherent electrophilicity of the ligand isonitrile compounds as electron-deficient substances.In addition,the chiral Pd-COMFs were obtained with good stability and were used as reusable chiral catalysts for efficient catalysis of the asymmetric Strecker reaction and the asymmetric Suzuki-Miyaura cross-coupling reaction in a multiphase manner.Ⅱ.Constructed an organometallic didentate formamide ligand based on（S）-Ni-bis（acyclic azocarbin）（（S）-Ni-BADC）and used it as a building block to achieve its assembly with tridentate amine ligands to obtain a single chiral CCOF through the construction of imino bonds.Firstly,（S）-Ni-（BADC）-bis-aldehydes were synthesized and then linked with1,3,5-tris（aminophenyl）benzene（TAPB）linker to form a COFs,namely（S）-Ni-BADC-CCOF.the obtained single chiral COFs are well applicable and this organometallic material is expected to serve as a reusable chiral catalyst to facilitate in a multiphase manner the un symmetric Strecker and Suzuki-Miyaura cross-coupling reactions.In this study,two chiral crystalline porous framework materials were designed and synthesized using the same idea and two pathways,allowing chiral metal-ADC with catalytic activity to be introduced into both MOF and COF frameworks,which is usually not possible with known synthetic methods.This study not only provides a new pathway for the assembly and preparation of novel chiral MOFs and COFs materials,but also further establishes a research foundation for the integration of organometallic chemistry and crystalline porous materials.