The Construction Of Functional Coordination Compounds Via A Metallotecon Strategy

The synthesis and application of functional coordination complexes is a hot research topic in modern chemistry. Nevertheless, the synthesis of functional coordination complexes via a metallotecon strategy was still early in its development. Based on the Hard-Soft-Acid-Base (HSAB) theory, chelate effect and ligand metathesis, a series of functional coordination complexes were synthesized from different metallotecons. The gas storage and separation property, catalytic property and host-guest chemistry also were studied.(1) A stoichiometric (1:1) mixture of pyridine-2,n-dicarboxylate acid (n=4or5) and the corresponding two divalent transition metal ions (M=Co, Ni, Cu, Zn, Pd) in DMF at room temperature gave the metallotecons complexes in almost quantitative yields. The reaction of pyridine-2,n-dicarboxylate acid with Cu+and Pd+gave the linear ligands, but with Co2+, Ni2+, or Zn2+gave the anionic metallotecons with T shape. Using these metallotecons reacted with the coordination confined metal source [M(cyclam)]2+(ClO4)2(M=Ni2+, Zn2+), a series of coordination complexes were obtained. The gas storage and separation properties of these complexes were studied, and all these complexes showed well CO2separation property due to the N-H moiety or coordinatively unsaturated metal centers in frameworks.(2) Based on the HSAB theory, a metalloligand [Pd(H2bpydc)Cl2] was synthesized. Four porous heterometallic coordination polymers were synthesized from this metalloligand. All of them contain the well catalytic active moiety [Pd(diimine)Cl2] and present remarkable versatility for catalysing Suzuki-Miyaura and Heck reactions. These catalysts were easily separated from the reaction system and reused in the next reaction cycle.(3) A series of cavity-specific Cp*Rh-based heterometallic metallarectangles were synthesized from metallaligand. Using an enlarged linker led to interpenetrating structures as a compensation of the weak coordination bonds. This coordination-driven self-assembled Borromean link models were unprecedented. The synthetic simplicity and readily tunable and easily modifiable modular design is a distinct advantage of this catalytic directed assembly. With appropriate cavity size, the metallocycles showed enzyme-like catalytic properties with high efficiency and wide substrate selectivity in the acyl-transfer reaction between N-acetylimidazole and X-pyridylcarbinol. Although these exciting results suggest the potential of biomimicking, the synthesis of metallosupramolecular catalysts and understanding of interpenetration phenomenon whose development are still at infancy.(4) Reported here are the bottom-up synthesis and structural analysis as well as the adsorption property investigation of a series of isostructural metal-organic frameworks based on carborane backbones and Cu2(CO2)4units. All these complexes are2D grid structures composed of the four component rings. Using the linear p-CDC (P-CDCH2=1,12-dihydroxycarbonyl-1,12-dicarba-closo-dodecaborane) as backbone, only one type of ring formed. However, five types of rings may exist when m-CDCH2(m-CDCH2=1,7-dihydroxycarbonyl-1,7-dicarba-closo-dodecaborane) was used due to its varied orientation. Here, the solvent molecules play a key role in the formation of these complexes and the expected five types of rings were obtained. The gas sorption properties of these complexes were studied, and these frameworks preferentially adsorb CO2over both CH4and N2due to the coordinatively unsaturated copper ions.(5) Based on the rigid famework and lack of electronic system of2,4,6-Tri(4-pyridyl)-1,3,5-triazine (tpt), which was used as building blocks for the construction porous frameworks with sub-cage. Furthermore, the cation and anion exchange properties also were investigated.