Synthesis, Characterization, and Nanomaterials Generated from...

The impact on the morphology nanoceramic materials generated from group 4 metal alkoxides ([M(OR)₄]) and the same precursors modified by 6,6'-(((2-hydroxyethyl)azanediyl)bis(methylene))bis(2,4-di- tert-butylphenol) (referred to as H₃-AM-DBP₂ (1)) was explored. The products isolated from the 1:1 stoichiometric reaction of a series of [M(OR)₄] where M = Ti, Zr, or Hf; OR = OCH(CH₃)₂(OPr ⁱ); OC(CH₃)₃(OBu ^t); OCH₂C(CH₃)₃(ONep) with H₃-AM-DBP₂ proved, by single crystal X-ray diffraction, to be [(ONep)Ti( k⁴( O,O',O'',N)-AM-DBP₂)] (2), [(OR)M(μ( O)- k³( O',O'',N)-AM-DBP₂)]₂ [M = Zr: OR = OPr ⁱ, 3·tol; OBu ^t, 4·tol; ONep, 5·tol; M = Hf: OR = OBu ^t, 6·tol; ONep, 7·tol]. The product from each system led to a tetradentate AM-DBP₂ ligand and retention of a parent alkoxide ligand. For the monomeric Ti derivative (2), the metal was solved in a trigonal bipyramidal geometry, whereas for the Zr (3-5) and Hf (6, 7) derivatives a symmetric dinuclear complex was formed where the ethoxide moiety of the AM-DBP₂ ligand bridges to the other metal center, generating an octahedral geometry. High quality density functional theory level gas-phase electronic structure calculations on compounds 2-7 using Gaussian 09 were used for meaningful time dependent density functional theory calculations in the interpretation of the UV-vis absorbance spectral data on 2-7. Nanoparticles generated from the solvothermal treatment of the ONep/AM-DBP₂ modified compounds (2, 5, 7) in comparison to their parent [M(ONep)₄] were larger and had improved regularity and dispersion of the final ceramic nanomaterials.