| As a new cutting-edge science, supramolecular chemistry is one hotspot of the current researches. Molecular recognition is a very important part of supramolecular chemistry, has attracted much attention of many chemists in recent years.8 Hydroxyquinoline(8-HQ) unit is an ideal building block to construct supermolecular structure. With its specific coordinate feature, it can bond metal ions to self-assemble some oligomers possessing special capability. Thus, in this thesis, taking the 8-HQ as a body molecule, three new 8-HQ derivates as ligand were synthesized by modifying its group, then the coordination behavior of the ligands and the structure of complexes were studied in detail to elucidate the variety of those complexes and the recognition of some special metal ions while regarding them as a fluorescence probe, and some results list as following:1.Terpyridine(trpy) shows a good coordination capability and its aromatic ring is easily functionalized. So, a new ligand,4'-(4-[8-oxo-quinoline]benzyl)-2,2':6',2"-terpyridine, L1)is achieved by introducing it onto the backbone of 8-HQ, and five supermolecular compound, [Hg(L1)Cl2]2DMF(1), [Ag2(L1)2(NO3)2].2DMF(2), [Ag2(L1)2(ClO4)2].2DMF(3), [Cu2(L1)2(NO3)4].2DMF(4), [Cu2(L1)2(ClO4)4].2DMF(5), were also prepared. Based on the analysis of the crystal structures, the type of their hydrogen bonding,π-πstacking interaction and supramolecular structure were full discussed. It indicates that, the asymmetric unit of complex (1) consists of two crystallographic-separate complexes and two DMF molecules. It extends as a two-dimensional layered structure through the C-H…Cl H-bonds, C-H…O H-bonds andπ-πstacking interaction between the pyridine rings. The shape of complex (2) is a distorted box-like structure formed by [2+2], that is, two ligands and two sliver ions are bonded in head-to-trail pattern. Then through the existence of C-H…O H-bond, complex (2) stacks into a wave-like framework, and it also found that the weak pyridine ringπ-πstacking interactions occur between the neighboring molecules with 3.729 A spatial distance; complex(3) displays a similar distort box-like structure with complex(2), but the degree of distortion is less than that of the latter. It generates a 3-D structure derived from the cooperation of the H-bonds, which originated from the C, H of pyridine and the O of perchlorate, and the weakπ-πstacking come from the pyridine rings of the two ligands connecting in head-to trail mode. Although complex(4) and (5) reveal analogical contorted box-like structure that constituted with two ligands and two copper ions linking in head-to-trail form, the coordination environment of the center ions is different, the former is six-coordinated while the anion NO3- takes part in the coordination, and the anion ClO4- is not involved in coordination in the latter. The final accumulation of complex (4) is a 3D ladder structure with holes, it stems from the affection of the C-H…O H bonds andπ-πstacking interaction, while complex (5) forms a 2D wave-shaped structure. These results suggest that the anion can control and adjust the structure of supermolecular of the complexes. Furthermore, the fluorescence properties of sliver complex in solid/or solution and the redox character of Cu-L1 were also studied.2.To search for high-sensitive fluorescence probe, two half-flexible ligand,1,2 bis(O-[8-oxo-quinoline]cresol)ethane (L2) and 1,2-bis (-[8-oxygen-quinoline]cresol) ethane(L3), were obtained. During the study of ion selective identification of L2, it found that L2 exhibits an excellent reorganization to Ag+ in the methanol:water=3:7, pH=7.2 buffer solution system. In order to explore the corresponding mechanism, the crystal structure of complex (Ag-L2) was detected and one structure-similar ligands (L3) was synthesized to make a contrast with L2. It deduced that the chelation between L2 and Ag+ blocks the molecular excited state proton transfer process of the fluorescent probe L2. At the same time, the spatial distance of 8-quinoline oxygen atom lying in the both ends of L2 is suitable to the size of Ag+ ions. As a result, the fluorescence of L2 increases greatly when it selectively recognizes Ag+, implying it is a potential favorable fluorescence probe molecule. |
