Synthesis, Characterization, and Nanomaterials Generated from 6,6′-(((2-Hydroxyethyl)azanediyl)bis(methylene))bis(2,4-di-tert-butylphenol) Modified Group 4 Metal Alkoxides

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.