Self-assembly Of Functional Metal-organic Macrocycles And Their Applications

The study field of supramolecular chemistry is high-order and complicated system constituted from two or more moleculars through weak interaction between different molecules. The weak interaction between host and guest could lead to the structure changing of host and is the base of molecule recognition and heterogeneous/homogeneous catalysis. Synthetic and functional metal-organic macrocycles are important models to realize the process of enzyme catalysis and recognition. In homogeneous system, these cavity-containing compounds can encapsulate and stabilize guest substrates through weak interaction with selective signal response and chemical transformations can be catalyzed within these "microreactor". Using the metal-organic macrocycles having high symmetry and organic active sites as building blocks, microporous molecular materials packed with different type of cavities could be obtained in presence of different solvents or templates. These materials would adsorb and encapsulate some special substrates, display the advantages of heterogeneous catalysis. The present paper contains following several aspects:1. Self-assembly of metal-organic macrocycles containing amide groups as active sites and their applications in the sensor of nucleoside and glucosamine:Quinoline groups in the well-moderated ligands act as both the fluorophore units and parts of the coordination sites, and the amide groups as hydrogen bonding triggers for guest molecules, a truncated octahedral and two triangle metal-organic macrocycles (CA1,CA3 and CA4) have been assemblied using three mono-dentate ligands (L1,L3 and L4) incorporating with Pd2+. CA1 and CA3 have achieved selective fluorescent detection for uridine because of the two-fold complementary hydrogen-bonding between uridine and amide is stronger than that of the other three riboneclosides, CA1 had also demonstrated fluorescent response for glucosamine. In present of flexible chain acted as electronic-donor, CA4 demonstrated selective fluorescent detection for cytidine. Furthermore, the hydrogen-bonding between cytidine and CA4 could induce disassociation and recomposition process of CA4 so as to realize selective recognition for different bio-molecular.2. Microporous molecular materials containing metal-organic macrocycles as building blocks and their applications in heterogeneous catalysis:Upon introducing the multiple amide groups into a proper-flexible tetra-monodentate ligand (L2) as hydrogen bonding and weak-base catalysis actived sites, we have obtained two microporous molecular materials (CA2 and CA6) having different cavities in present of different solvents or templates. CA2 demonstrated size-selective catalysis for Knoevenagel condensation reaction in heterogeneous system. Upon introducing a flexible chain into the ligand (L5) containing tetra-monodentate binding sites, we have studied the effection of the flexible ligand for the stability and recombinational prccess of CA7 assembled from L5 and Pd2+ in solution. A quadrangle macrocycle (CA8) has been obtained using multi-dentate ligand (L6) and Ni2+. This tetramer has amino groups as guest interaction and weak-base catalysis actived sites. The hydrogen bond between amino and imine group and p-p interaction in different tetramer lead to 2D network and 1D channel in the crystal structure of CA8. CA8 demonstrated size-selective catalysis for Knoevenagel condensation reaction in heterogeneous system.3. Self-assembly of tetrahedral metal-organic cycles and their application in homogeneus catalysis:a serious of new molecular tetrahedrons (CA9,CA10,CA11) were prepared via self-assembly between Zn2+,Cd2+,Co2+and tri-dimdentate schiff-base ligand (L7) containing large aromatic and conjugated group as p-p interaction sites. Host-guest complexation behaviour between the tetrahedron compound and anthracene-9-carboxylicacid was investigated using the methord of fluorometry titration. The cation tetrahedron host could encapsulate two anthracene-9-carboxylicacid vis static and p-p interaction, and the selective photodimerization reaction of typically unreactive substrates was engineered using a self-assembled molecular falsk. The molecular tetrahedron brang the reactions in close proximity,fixed their relative orientations within the restrictive cavity and demonstrated the ability of microreactor.