Controllable Construction Of Metal-Organic Supermolecular Systems And Their Photochemical Properties

A variety of different metal-organic supermolecules represent a unique class of functional molecular containers that display interesting molecular recognition properties and fascinating reactivity reminiscent of the natural enzymes. They show promise in separation of molecules and ions, recognition of small molecules, catalysis of special reaction, stabilizing intermediate and so on. Presently, how to introduce the appropriate signal output units and active units to construct the special structures applied to the identification and catalytic systems, which can effectively cooperate many kinds of weak interaction to generate the intuitive and simple signal output is the problem to be solved immediately. In order to solve the above problems, this paper includes three aspects of the design:1) introducing dihydropyridine amido group (DHPA) to enhance reaction activity of system, improve ability of recognization for guests and work as potential aromatic stacking sites;2) introducing excellent fluorescent units as the linkers of metal-organic supramolecular systems to build fluorescent MOPs with cavities and work as potential aromatic stacking sites;3) choosing amide groups to improve biological compatibility, construct hydrophilic/hydrophobic environment and work as hydrogen bonding sites, which will further develop application of these systems in the field of biological, energy and so on.By incorporating NOO tridentate chelators into rationally designed ligand systems, a well-defined molecular cube Ce-TBDS and a bicoronal trigonal prism Ce-TBBS were achieved via self-assembly. The narrow edge of the opening is less than5.0A, hardly allowing small molecules’ingress and egress. The flexibility of the ligands backbone makes the four ceriums connected far from a plane, the narrow diameter of the openings thus enlarged to8.0A, possibly allowing natural mono-or disaccharides ingress and egress. The triple-stranded helicates Ce-DBDS and Ce-DBBS were achieved via self-assembly from bis-tridentate ligands Structure analysis of Ce-DBDS shows that six oxygen atoms of the ether bond groups on the ligands form a lantern-like cavity inside the compound. Thus the’Molecular Lantern’exhibit crown ether recognition behaviors and could be applied in luminescent magnesium chemosensors. Ce-DBBS which contains three full substituted benzyl groups exhibited better sensitivity by cation-π interaction between Mg2+and benzyl group, compared to the Ce-DBDS.Novel basket-like metal-organic tetragon compound Ce-ZL consisting of π-π stacking units and hydrogen bonding trigger sites was prepared by a tridentate NOO units containing amide groups within a central carbazole ring. Ce-ZL having size restrictions and integrating multiple weak interactions, such as hydrogen bonding,π-π stacking and hydrophilic/lipophilic interactions in a controllable way within its cavity, was used to selectively detect the adenosine trisphosphate (ATP) among the twelve ribonuclotides in aqueous media, exhibiting the advantage of stereoselectivity in these cage-like structures. At the same time, carbazole fragment can work as the excellent photosensitizer, Ce-ZL was developed to capture the biomimetic [FeFe]-H2ases for light driven H2production with a TON value about33. The system exhibited enzymatic behaviour and its activity was inhibited by the encapsulation of ATP.By incorporating the dihydropyridine amido group (DHPA) as the reactive-site into rationally designed ligand systems, a well-defined molecular tetrahedron Ce-ZPS and a octahedron Zn-ZPT were achieved via selfassembly. The four ligands of Ce-ZPS positioned individually on the four triangle faces of the tetrahedron and its active site positioned interior of cavity to provide an efficient interaction environment for detecting RDX. The detection limits reach10ppb. Compound Ce-ZPS is the first example of metal-organic polyhedra successfully used for explosives detection. The d10transition metal complexes can give excellent luminescence due to their special electron structure. The limit of detection of Zn-ZPT was improved to1ppb with direct observing by naked eye. Another system Co-ZPB supramolecular complex has been developed for H2generation. The efficiencies of hydrogen production relied on host-guest behaviors between Co-ZPB and the dyes, indicating that the supramolecular host-guest interactions play important roles for H2production. Due to the introduction of the cofactor DHPA, TON are improved up to880. This supramolecular system provided a new platform for H2production.