Iridium(?) Complexes-Containing Metal-Organic Supramolecules:Controllable Construction And Applications

Research on the supramolecular self-assembly of metal-organic macrocyles and polyhedra is one of the important frontiers and hot spots in chemical fields. Rational design and controllable construction of these metal-organic macrocyles and polyhedra with different cavity environments, such as cyclics or cage-shaped, seems very critical to mimic the superior properties of nature enzyme. The challenges on this issue are how to introduce functional ligands with special physical and chemical properties into metal-organic supramolecular assemblies, and rational arrangement of active sites and regulation the environment.Since a series of cationic or neutral Ir(?) complexes have been widely used in biological recognition and photocatalysis fields, in this thesis, we focused on the rational design, controllable construction of the metal-organic macrocyles and polyhedra that contain Ir(?) complexes. The performance of these target discrete supramolecular assemblies has also been explored.(1). By incorporating "NNO" tridentate chelators into the cationic Ir(?) metalloligands Ir(3ppy)2bpy(PF6) and Ir(3Lppy)2bpy(PF6) through Schiff-Base reaction, metal-organic macrocyles C1 and C2 were constructed through subcomponent self-assembly. Complex Cl has a 9.08 A× 9.16 A square window and the lager metallic macrocyle C2 owns a 13.28 A x 13.13 A square window. Two trigonal bipyramid complexes P1 and P2, each bearing two fac-configuration tripodal ligands fac-Ir(4ppy)3 or fac-Ir(4Lppy)3, were finally obtained in quantitative yields, and the three Zn(II) ions occupied the equatorial plane. The distance of Ir(?)-Ir(?) and Zn(?)-Zn(?) are 11.70 A and 7.80 A, respectively. There is a 7.89 A x 7.47 A window of P1. Metal-organic polyhedron P2 has a more larger cavity, the distance of Ir(?)-Ir(?) and Zn(?)-Zn(?) are 18.45A and 11.82 A, respectively. Using mer-configuration ligand mer-Ir(4ppy)3, new isostructural pseudo octahedron geometry metal-organic polyhedra 01 were successfully obtained. The four metal ions in the equatorial plane construct a somewhat distorted rectangular window with the dimensions 9.40 A x 6.40 A. The znic ions in the axial positions have a distance of 24.76 A.(2). By incorporating "NN" bidentate chelators into the neutral Ir(?) metalloligands fac-Ir-NH2, a trigonal bipyramid polyhedra Ir-Znl was obtained through subcomponent self-assembly when combined with 2-formylpyridine and Zn(BF4)2.The three zinc atoms constructed the equatorial plane and the two iridium atoms occupied the axial positions. Each zinc atom was coordinated by two NN bidentate chelators from two different iridium containing blocks. The fifth site on the three Zn(?) centers should be assigned as one OH', one F- anion and one H2O molecule respectively. The coordinated geometry of the zinc atoms and hydrophobic cavity in Ir-Znl were similar to the active sites and the hydrophobic pocket of the carbonic anhydrases in nature, which induced atmospheric carbon dioxide transformation as carbonate with cooperative bonding to the three metal centers. The decay curve of the luminescence spectra of Ir-Zn1 upon bubbling CO2 exhibits a typical first-order dynamics behavior with the rate constant calculated as ca.0.092 min-1. When introducing one Cl in the cavity of Ir-Zn1, the complex Ir-Zn1(?)Cl- was obtained and showed no catalytic property with CO2. which clearly demonstrates that this transformation occured in the inner cavity. The analysis of crystal information of complex Ir-Zn1(?)CO2 made the catalyst process more clear. Moreover, complex Ir-Znl also induced sulfur dioxide as sulfite and captured in the cavity of the metal-organic polyhedron in a similar process.(3). By introducing photoactive fac-Ir(ppy)3 as a ligand backbone to constrain the coordination geometry of cobalt ions, multifunctional Ir-Col capsule was achieved through subcomponent self-assembly. Ir-Co1 combined photocatalysis and transition metal activation synergistically and exhibited efficient catalytic ability on visible light activated a-trichloromethylation with 86%-96% yield. Capsule Ir-Col showed induced-fit capsule-capsule conversion to a new capsule Ir-Co2 by cooperative binding one carbonate anion with the equatorial Co(?) centers. The elaborative construction and modulation catalysts active sites may give inspiration to controllably design external stimuli-responsive functional molecules and materials that are capable of achieving complex functions which mimic their biological counterparts.