NIOBIUM(V) ALKOXIDES - SYNTHESIS, STRUCTURE, AND CHARACTERIZATION OF [NB(MU-OCH2CH3)(OCH2C(CH3)(3))(4)](2), 2O)(CH2-MU-O)(C(O)(2))]NB-2(MU-O)(OCH2CH3)(5))(2), AND ([H3CC(CH2O)(2)(CH2-MU-O)]NB(OCH2CH3)(2))(2) FOR PRODUCTION OF MIXED-METAL OXIDE THIN-FILMS

We have synthesized and isolated a number of unique niobium alkoxide c ompounds and introduced them into novel solution processes for the pro duction of lead magnesium niobate oxide (PMN) and niobium-doped lead z irconate 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)et hane (THME-H-3) were independently reacted with Nb(OEt)(5) to reduce t he 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 unsy mmetrical ''(EtO)(2)Nb(mu-O)Nb(OEt)(3)'' units are bridged by two tetr adentate BHMP ligands. The THME moiety of 3 acts as a chelating, unide ntate-bridging ligand forming a symmetrical dinuclear species, wherein each Nb atom possesses two terminal ethoxides. The synthesis, charact erization, structural aspects, and solution properties of 1-3 are repo rted. The resulting morphological and electrical changes in the proper ties of the resulting electroceramic PMN and PNZT films due to the inc orporation of these Nh alkoxides are also reported.