Niobium(V) alkoxides.: Synthesis, structure, and characterization of [Nb(μ-OCH2CH3)(OCH2C(CH3)3)4]2, {[H3CC(CH2O)(CH2-μ-O)(C(O)2)]Nb2(μ-O)(OCH2CH3)5}2, and {[H3CC(CH2O)2(CH2-μ-O)]Nb(OCH2CH3)2}2 for production of mixed metal oxide thin films

We have synthesized and isolated a number of unique niobium alkoxide compounds and introduced them into novel solution processes for the production of lead magnesium niobate oxide (PMN) and niobium-doped lead zirconate titanate oxide (PNZT) materials. A more sterically demanding analogue to Nb(OEt)(5) (Et = CH2CH3) was isolated as [Nb(mu-OEt)-(ONp)(4)](2) (1, Np = CH2C(CH3)(3) )by alcoholysis exchange. 1 crystallized in an edge-shared bioctahedral dinuclear arrangement with the smaller ligands acting as the bridging moieties. Multidentate ligands such as bis(hydroxymethyl)propionic acid (BHMP-H-3) and tris(hydroxymethyl)ethane (THME-H-3) were independently reacted with Nb(OEt)(5) to reduce the number of terminal ligands, yielding [(mu-BHMP)Nb-2(mu-O)(OEt)(5)](2) (2) and [(mu-THME)-Nb(OEt)(2)](2) (3) respectively. For 2, two unsymmetrical "(EtO)(2)Nb(mu-O)Nb(OEt)(3)" units are bridged by two tetradentate BHMP ligands. The THME moiety of 3 acts as a chelating, unidentate-bridging ligand forming a symmetrical dinuclear species, wherein each Nb atom possesses two terminal ethoxides. The synthesis, characterization, structural aspects, and solution properties of 1-3 are reported. The resulting morphological and electrical changes in the properties of the resulting electroceramic PMN and PNZT films due to the incorporation of these Nh alkoxides are also reported.