Syntheses, Structures And Properties Of Zn/Cd Fluorescent Coordination Complexes

In recent years, the design and synthesis of metal-organic coordination complexes has become an attractive and promising research field not only because of their various structures, but also due to their potential applications in optics, electrics, magnetism, gas storage and separation. The most fascinating task in this field is to obtain the complexes with novel structures and unique properties through selecting appropriate organic ligands and metal ions as well as controlling the influential facors in self-assembly processes. Therefore, it is very important to investigate the self-assembly processes and many factors such as different organic ligands, metal ions, pH value, reaction times, etc., influencing on the structural construction of functional complexes. However, it is still a great challenge to generate the controllable MOFs with desirable structures and functions.As is well known, the electron-rich (d10) transition metal complexes exhibit good luminescent properties. Based on the afore-mentioned points, in this thesis, we selected the mixed rigid carboxylate and N-containing ligands [5-sulfoisophthalic acid sodium salt (NaH2sip),5-nitroisophthalate acid (H2ip-NO2)、5-aminoisophthalate acid (H2ip-OH),2,5-di(1H-imidazol-1-yl)thiophene (H2Dimt),1,2-di(1H-tetrazol-5-yl)ethane (H2dte) and1,2-di(1H-tetrazol-5-yl)propane (H2dtp)] to react with transition metal ions (Zn2+, Cd2+) under the hydrothermal and solvothermal conditions to give rise to nine metal-organic coordination complexes [Cd(HDimt)(sip)(H2O)]n (1),[Cd3(Dimt)2(sip)2(H2O)6-2H2O]n (2),[Cd3(Dimt)4(sip)2-2H2O]n (3),[Zn1.5(sip)(Dimt)(H2O)·(H2O)1.5(CH3OH)0.5]n (4),[Zn1.5(sip)(Dimt)2(H2O)-(H2O)2.5]n (5),[Zn(ip-NO2)(Dimt)]n (6),[Zn(ip-OH)(Dimt)]n (7),[Zn(dte)(OCH2O)o.5-(CH3OH)0.5-(H2O)0.5]n (8) and [Zn2(dtp)(OH)2]n (9). The single crystal X-ray diffraction analysis showed that complexes1is one-dimensional chain structure, complexes2,4,9and7possess two-dimensional layer structures, while complexes3,5,8and6are three-dimensional networks. Their IR spectra, X-ray powder diffraction, thermogravimetric analysis, elemental analysis and luminescent properties were also investigated in detail.