Self-Assembly And Adjustment Of Crystal Structures Of Complexes Based On A Series Of Flexible And Rigid Bipyridine Ligands

In the realm of supramolecular chemistry, great interest has recently been focused on the crystal engineering of coordination frameworks due to their intriguing architectures, new topologies, intertwining and interpenetrating phenomena and their potential applications in microelectronics, nonlinear optics, molecular selection, ion exchange, catalysis and magnetic materials. Molecular self-assembly has emerged as an attractive approach for the fabrication of new materials. This process involves the spontaneous aggregation of small molecular building blocks in solution that recognize each other through multiple of molecular self-assembly, the author carried out a study on designing basic building blocks and constructing new series of supramolecular network solids, and wishes to find some new materials with excellent properties. In this thesis, the history and the current progress had been reviewed. Based on the building blocks of bipyridine, five novel supramolecular compounds have been synthesized in conventional synthesis condition (Crystallization from saturated solutions) and in diffusion condition. They are listed as follows: [Cu₂(maa)₄(bpp)] (1), [Cu₃(maa)₆(bpp)₂] (2), [Cu₄(maa)₈(bpp)₄(H₂O)₂]·2H₂O (3),[Co(bpp)₂(H₂O)₂]·fum·8H₂O (4), [Cu₂(cro)₄(bpp)]·H₂O (5), [Cu₂(maa)₄(bpe)] (6). The dinuclear paddle-wheel copper(II) units Cu₂(maa)₄ are rationally tuned, forming three classes of isomorphous compounds with bpp at controlled ligand-metal molar ratios, and lead to three coordination polymers (1-3) having the same one-dimensional zigzag characteristics but different mono- and di-nuclear nodes. Complex 3 presents a remarkable and unprecedented topology of a triple-stranded molecular braid which looks just like a hair plait. Moreover, it shows an interesting behavior in which the interlaced chains are self-recognized by hydrogen bonds between them. Complex 4 is obtained from an aqueous reaction at room temperature, and exhibits a two-dimensional supramolecular water layer containing (H₂O)₁₈ morphology through dianion template. Using a linear dimetallic spacer Cu₂(cro)₄ as building block, we have successfully synthesized a 1-D coordination polymer 5. Sinusoidal channels are formed among every adjacent four chains, and water-dimers are encapsulated in thechannels. Through TGA and XRPD analysis, we conclude that the material of 5 belongs to the second generation of porous material. In addition, we have also carried out some studies about rigid ligand, and have synthesized 1-D polymer [Cu2(maa)4(bpe)] (6).