Syntheses, Structures And Properties Of Novel Tungstoantimonates Based On [B-SbW₉O₃₃]^9- Building Units

In this dissertation, on the basis of molecular design and self-assembly principle, by employing the hydrothermal technique and the conventional aqueous condition, twenty-two novel tungstoantimonate (TA) derivatives based on [B-SbWgO33]9- building blocks have been successfully synthesized. These complexes were further characterized by single-crystal X-ray diffraction, element analyses, IR spectra, fluorescence, magnetic properties, electrochemical and electrocatalytic properties.The dissertation can be divided into three sections to introduce my work during the master study:Part I. Four novel organic-inorganic hybrid transition-metal substituted TAs [Cu(en)2(H2O)]4[Cu(en)2(H2O)2][Cu2Na4(B-a-SbW9O33)2]-6H2O (1), [Na(H2O)6]2H4[Mn(H2O)3]2{Mn7 (H20)8(C2O4)3[B-a-SbW9033]2}·27H2O (2),Na4H6[Co3W(H2O)4(GLY)2(OH)4] [B-β-SbW9O33]2·36H2O (3) and Na6Fe4(H2O)8(PCOA)2(B-β-SbW9O33)2-PCOA-26H2O (4) have been successfully prepared.1 was synthesized by the reaction of simple materials Sb2O3, Na2WO4·2H2O with the CuCl·2-2H2O in the existence of ethanediamine (en) under hydrothermal conditions, whereas 2-4 were obtained via the conventional aqueous solution method by introducing transition-metal cations to the trivacant Keggin-type [B-a-SbW9O33]9- system with the attendance of the small organic ligands as structure-stabilizing agents. The sandwich-type dimers 1 and 2 are all constructed from two equivalent trivacant Keggin [B-a-SbW9O33]9- subunits sandwiching a hexagonal metal cluster, while 3 and 4 are Krebs-type derivatives with two organic ligands substituting two water molecules on the outer metal centers.2 represents the one-dimensional sinusoidal chain based on sandwich-type TA building blocks through Mnu-carboxylate double bridges, but 1,3 and 4 all show an isolated structure. Magnetic measurements indicate that 1 displays the weak ferromagnetic exchange interactions and 2 exhibits the strong ferromagnetic couplings.Part Ⅱ. Two types of novel lanthanide-substituted TAs [H2N(CH3)2]11H[(B-α-SbW9O33)(Er2 (H2O)2Sb2WO3)(SbW15O54)]·17H2O (5), Na20H2[(Tb4Sb6W2(H2O)6O12)(SbW8O31)2(B-α-SbW9O33)2]·44H2O (6), Na20H2[(Dy4Sb6W2(H2O)6O12)(SbW8O31)2(B-α-SbW9O33)2]·27H2O (7),Na4H18[Ho4Sb6W2(H2O)6O12 (SbW8O31)2(B-α-SbW9O33)2]·51H2O (8) and Na8H14[(Er4Sb6W2(H2O)6O12)(SbW8O31)2(B-α-SbW9 have been isolated under conventional aqueous solution condition.5 represents the first TA simultaneously containing the trivacant Keggin polyoxoanion [B-α-SbW9O33]9- and trivacant Dawson-like [SbW15O54]15- fragments, and the SbⅢ and ErⅢ ions acting as linkers joint these two fragments together leading to a sandwich-type structure. The common feature of 6-9 is that two tetravacant Keggin{SbW8} units are linked with each other through the W-O-Ln-O-W bridges generating a dimeric unit {[Ln(SbW8)]2}, then the dimeric unit links to two [B-α-SbW9O33]9- fragments via{Ln2Sb3W} clusters, leading to a tetrameric Ln-substituted TA. The fluorescence behavior of 7 has been discussed.Part Ⅲ. Undet the conventional aqueous solution condition, two series of TA-based FeⅢ-LnⅢ heterometal derivatives [Pr(H2O)8][Pr(H2O)6][FeⅢ4(H2O)10(B-β-SbW9033)2]·16H20 (10), NdNa3[Fe4(H2 O)10(B-β-SbW9O33)2]·36H2O (11), [Ln(H20)7]2[Fe4(H20)10(B-β-SbW9O33)2]·22H2O (Ln= TbⅢ, DyⅢ, LuⅢ, YⅢ) (12-15) and [Ln(H2O)8]2[Fe4(H2O)8(L-thr)2][B-β-SbW9O33]2·22H2O (Ln= PrⅢ, NdⅢ, SmⅢ, EuⅢ, GdⅢ, DyⅢ, LuⅢ) (16-22) have been synthesized.1-5 represent the first purely inorganic transition-metal-lanthanide heterometallic TAs based on trilacunary Keggin [B-β-SbW9O33]9- units.10 and 11 exhibit the first 2-D extended sheet constructed from the tetra-FeⅢ substituted sandwich-type units [Fe4(H2O)10(B-β-SbW9033)2]6- through LnⅢ linkers while 2-5 are isolated structure.16-22 respresent the first TA-based FeⅢ-LnⅢ heterometallic hybrids functionalized by amino acid ligands, which all consist of a sandwich-type dimermic [Fe4(H2O)8(thr)2(B-β-SbW9O33)2]6- subunit with two supporting [Ln(H2O)8]3+ cations on both sides. The solution electrochemical and electrocatalytic properties of 10 and 12 and the solid-state electrochemistry and electrocatalytic properties of 16 have been measured in 0.5 mol·L-1 Na2SO4+ H2SO4 supporting electrolyte. The fluorescence behavior of 19 and the magnetic properties of 18 and 21 have also been studied.