Synthesis And Structural Chemistry Of Metal Carboxylates Containing Easily Hydrolyzed Lead And Sin Et Al

Metal-organic complexes have a wide range of applications, due to their special properties in electro-conductivity, magnetism, optics, magnetics, selective catalysis and molecular recognition. Employing the ideal of molecular design and crystal engineering to multiply and assemble functions, taking another further step to intensify the relationship between functional materials and their properties, using metal ions as metal center and organic-ligands on the complexes with highly order structure coordinative bonds and hydrogen bonds, that are one of the active fields studying on the metal-organic complexes. In this paper, we select oxalate acid and metals which have a strong tendency toward hydrolysis as our mainly subject, exploring the condition of synthesis and conquering the question of easily hydrolyzed polymers for lead and bismuth. Through its versatile coordination and connecting mode of oxalate, the studies of the complexes with three kinds of novel structures and properties are reported. So far we had made achievements in such aspect: 1. Five new compounds were designed and prepared by hydrothermal method and one were designed and prepared by solution methods. For the six compounds, they can be divided into three groups: (1) zero-dimensional complexes: ( H₂en)₂(H₃O)[Sb(C₂O₄)₄] ·H₂O Compound 1 (2) compound with two-dimensional chain:: ( H₂en)(H₃O)[(BiPb(C₂O₄)₄(H₂O)₂)]·2(H₂O) Compound 2 (3) compounds with three-dimensional open-framework structure: (H₂en)₂(H₃O)₄ Zr₂Pb₂(H₂O)₂(C₂O₄)₉·3H₂O Compound 3 (en)[Ba₂(H₂O)₅Sn(C₂O₄)₄] Compound 4 (4) others compounds with three-dimensional structure (2H₃O)(K₂Na₂)(V₁₀O₂₈)·10H₂O Compound 5 CoK₂V₄O₁₂ Compound 6 2. For some compounds, their IR, Raman, DRS, fluorescent spectra and TGA are studied. In IR and Raman spectra, we ascribe the characteristic peaks of metal oxalates to corresponding vibration frequencies and find the characteristic peaks are related to the connecting mode of the oxalates, the coordination environment, the different organic ligands and so on; From the Correlation analysis of two-dimensional IR spectroscopy for compound 5, its graphs give us a good indication of the existence of two distinct relaxation mechanisms in the system. Moreover, peaks located on Synchronous (A) and asynchronous (B) IR correlation spectra (2D) spectral plane provide information on connectivity and interactions among functional groups associated with the IR bands, between 400 to 1100 cm-1, anti-stretching vibrations of the V=O is more sensitive to the thermal interfere than stretching vibrations of the V=O. The π→π* bands and LMCT bands about polymer to metal are also discussed, and its intensity and the wave center are different with different coordinated mode of oxalates. The electronic transition energy of tetra-coordinated oxalates is smaller than that of bi-coordinated oxalates obviously. Accordingly, the peak value is larger. Besides, we studied the fluorescent spectra of some solid compounds; its fluorescent time is so longer, because of its existence of the metal (lead and bismuth) in the compound. From TGA diagram of the compounds, we find the process of making metal oxide with the rise of temperature, corresponding to the lose of crystal waters and organic molecules respectively. Thus, it can be the precursor of making lead oxide and bismuth oxide which have catalytic characteristics. 3. The units of [Sb(C2O4)4]5-, [(BiPb(C2O4)4(H2O)2)]3-, [Ba2(H2O)5Sn(C2O4)4] and (2H3O)K2Na2(V10O28)·10H2O are calculated by using the quantum chemistry method. Through the distribution of net charge, we discussed the extent of electron delocalization for bi-coordinated oxalates and tetra-coordinated oxalates. The results show that the latter is larger than the former, and the difference of bond length is smaller. The quantum chemistry calculation of compound 5 with open-framework structure proves that both atom Na and K make covalent with the coordinated water molecules.