Crystal structure and solid-state transformations of Zn–triethanolamine–acetate complexes to ZnO

Abstract

The rapid and massive formation of a foamy precipitate while reacting zinc acetate (Zn(Ac) 2 ) and triethanolamine (TEA) in proper conditions led to an unravelled complex and a molecular tetrametallic zinc cluster: their synthesis was optimised and they were characterised by single crystal X-ray diffraction. The structure shows the direct link of the acetate anion to the Zn cation, a feature not observed in parent compounds. The structural and chemical evolution of these materials upon heating have been studied, targeting the production of zinc oxide thin films or particles with particular properties. The phase transitions occurring during thermal treatments and the conversion to ZnO were studied by in situ X-ray powder diffraction, thermo-gravimetry and Raman spectroscopy. The cluster structure can be considered an even more interesting precursor for zinc oxide as nano-aggregates of four ZnO moieties are already present and the formation of ZnO particles requires a smaller number of broken and newly formed bonds. A third metastable hydrated phase was identified, but not structurally characterised because of its instability, thus completing the exploration of the polymorph landscape of the title compound.

New Zn(II) Coordination Polymers Constructed from Amino-Alcohols and Aromatic Dicarboxylic Acids: Synthesis, Structure, Photocatalytic Properties, and Solid-State Conversion to ZnO

“…119 Another study presents several discrete zinc(II)−triethanolamine−acetate complexes, which were further used as precursors for ZnO nanoparticles. 120 Many polymeric zinc complexes are characterized by robust and thermally stable open-framework structures and some of them were already evaluated as heterogeneous photocatalysts, due to their versatility in a wide range of reactions. 121−123 Selective oxidation using recoverable heterogeneous catalysts has become an important target of the most recent decades, representing the most important strategy to selectively introduce oxygen atoms in organic molecules.…”

Composition-Tailoring of ZnO-Hydroxyapatite Nanocomposite as Bioactive and Antibacterial Coating

“…TEOA, a well-known biocompatible dispersant, was added to increase the stability of the NPs in 2-PrOH. TEOA forms a strong complex with Zn 2+ and therefore can increase the stability of ZnO by increasing the ζ-potential . Specifically, TEOA as a strong organic base can induce the ionization of alcohols to form alkoxide ions and positively charged ammonium, which can be adsorbed on the surface of NPs and increase the ζ-potential …”

“…TEOA forms a strong complex with Zn 2+ and therefore can increase the stability of ZnO by increasing the ζ-potential. 37 Specifically, TEOA as a strong organic base can induce the ionization of alcohols to form alkoxide ions and positively charged ammonium, which can be adsorbed on the surface of NPs and increase the ζ-potential. 38 Table 1 summarizes the First, we investigated the impact of the applied potential on the coating composition, taking into account that both of the NPs have similar ζ-potentials.…”

ZnO Coatings with Controlled Pore Size, Crystallinity and Electrical Conductivity

“…3 h) decompose through a series of small plateaus. Conterosito et al [35] studied the decomposition of similar triethanolamine complexes and did not observe intermediate formation of zinc carbonate. The conversion of the N-containing ligand complexes into zinc carbonate is therefore unlikely.…”