title: Templating Influence of Molecular Precursors on Pr(OH)3 Nanostructures.
abstract: Four new praseodymium alkoxo and amido compounds ([Pr3(μ3-OtBu)2(μ2-OtBu)3(OtBu)4(HOtBu)2] (1), [Pr{OC(tBu)3}3(THF)] (2), [PrCl{N(SiMe3)2}2(THF)]2 (3), and [PrCl{OC(tBu)3}2(THF)]2 (4)) were synthesized and structurally characterized by single-crystal X-ray diffraction analysis. Application of these compounds in solvothermal synthesis of praseodymium oxide/hydroxide nanostructures showed their templating influence on the morphology and phase composition of the resulting solid-state materials. Differential reactivity of the chosen alkoxide ligands toward water and the different arrangements of metal-oxygen units in the studied precursor compounds strongly influenced the kinetics of hydrolysis and cross-condensation reactions as manifested in the morphological changes and phase composition of the final products. Thermal decomposition studies of 1-4 confirmed their conversion into the corresponding oxide phases. Activation of compounds 1, 2, and 4 by either a base or a stoichiometric amount of water showed the distinct influence of their chemical configuration on the obtained nanopowders: whereas 1 solely produced nanorods of Pr(OH)3, 2 predominantly formed a mixture of rod-shaped and spherical particles. The solvothermal decomposition of 4 resulted in Pr(OH)2Cl or PrOCl due to the presence of Cl ligands in the molecular precursor. The resultant materials were thoroughly characterized to demonstrate the relationship between precursor chemistry and the processing parameters that are clearly manifested in the morphology and phase of the final ceramics.
authors.affiliation: †Institut National de la Recherche Scientifique-Énergie Matériaux Télécommunications, Université du Québec, 1650 Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2, Canada.|‡Leibniz Institute of New Materials, Im Stadtwald, Building D2 2, 66123 Saarbruecken, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Hemmer
authors.affiliation: ‡Leibniz Institute of New Materials, Im Stadtwald, Building D2 2, 66123 Saarbruecken, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Cavelius
authors.affiliation: §Institute of Inorganic Chemistry, Saarland University, P.O. Box 151150, 66041 Saarbruecken, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Huch
authors.affiliation: ∥Institute of Inorganic Chemistry, University of Cologne, Greinstrasse 6, 50939 Cologne, Germany.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Mathur