Glycol Modified cis-diisopropoxy-bis(N-phenylsalicylideneiminato) zirconium(IV): Syntheses, Characterization and Their Low Temperature Transformation to Nanocrystalline Zirconia

Abstract

Zr(OPrᵢ)(4)center dot PrᵢOH reacts with N-phenylsalicylideneimine in anhydrous benzene in 1 : 2 molar ratio to afford [Zr{O(C₆H₄)CH=NPh}₂{OPrⁱ}₂] (1). Further reactions of 1 with various glycols yield heteroleptic complexes of the type [Zr{O(C₆H₄)CH=NPh}₂{O-G-O}] [where-G-= (CH₂)₂ (2), (CH₂CHCH₃) (3), (CH₃CHCHCH₃) (4), (CH₂CHC₂H₅) (5), (CH₂)₃ (6), (CH₂CH₂CHCH₃) (7), and (CH₂)₆ (8)]. All new derivatives have been characterized by elemental analyses, FTIR and NMR (¹H and ¹³C{¹H}) studies. FAB mass spectra of 1 and 7 revealed the monomeric nature of these complexes. Complete hydrolyses and low temperature transformations of 1 and 7 using Sol-Gel technique formed tetragonal phase of ZrO₂ at 700 degrees C, whereas transformation of tetragonal to monoclinic phase occurred at 900 degrees C. SEM observations of these samples indicate formation of agglomerates of nanocrystalline zirconia (Scherer analysis).