title: Fluorinated Cerium(IV) Enaminolates: Alternative Precursors for Chemical Vapor Deposition of CeO2 Thin Films.
abstract: High-yield synthesis of four new fluorinated enaminones LH2 (RfC(O)C2H2NH)2C2H4 (Rf = CF3 (2a), C2F5 (2b), C3F7 (2c)) and (F3CC(O)C2H2NH)2C3H6 (2a') as dianionic ligands is described. The ligands were characterized in solution (via nuclear magnetic resoannce (NMR)) as well as in the solid state (via X-ray diffraction (XRD)). The ligating ability of the enaminones was verified by reacting them with [Ce2(O(i)Pr)8(HO(i)Pr)2], which resulted in monomeric cerium(IV) complexes [CeL2] (3a-c, 3a') based on tetradentate chelation of the ligands. Cerium enaminolates were comprehensively analyzed by NMR spectroscopy, mass spectrometry, and single-crystal XRD studies to verify their monomeric nature. High stability under ambient conditions and high volatility makes them a potential precursor for the gas-phase synthesis of CeO2. Complexes 3a and 3b were applied as precursors in thermal and plasma-enhanced chemical vapor deposition to obtain crystalline ceria films with different surface morphologies. The purity and surface states of the films were analyzed by X-ray photoelectron spectroscopy, which revealed a high amount of Ce(3+) on the subsurface of CeO2 films.
authors.affiliation: Institute of Inorganic Chemistry, University of Cologne Greinstraße 6, D-50939 Cologne, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Schläfer
authors.affiliation: Institute of Inorganic Chemistry, University of Cologne Greinstraße 6, D-50939 Cologne, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Graf
authors.affiliation: Institute of Inorganic Chemistry, University of Cologne Greinstraße 6, D-50939 Cologne, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Fornalczyk
authors.affiliation: Institute of Inorganic Chemistry, University of Cologne Greinstraße 6, D-50939 Cologne, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Mettenbörger
authors.affiliation: Institute of Inorganic Chemistry, University of Cologne Greinstraße 6, D-50939 Cologne, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Mathur