화학공학소재연구정보센터
Inorganic Chemistry, Vol.50, No.23, 12126-12132, 2011
2,4-Pentanediolate as an Alkoxide/Diketonate "Hybrid" Ligand and the Formation of Aluminum and Zirconium Derivatives
When 2,4-pentanediol (2,4-H(2)pd) is deprotonated, the resulting dianion (2,4-pd) serves as a type of "hybrid" ligand, i.e., an alkoxide that possesses structural features of a beta-diketonate. 2,4-Pentanediol reacts with Al(O-s-Bu)(3) and Zr(O-i-Pr)(4) to form chelated multinuclear complexes. The aluminum-containing product is first isolated as the insoluble [Al(2,4-pd)(2,4-Hpd)](n); on sublimation, a hydrocarbon-soluble mixture of polymetallic species is generated. Mass spectral evidence suggests that both Al-4(2,4-pd)(6) and Al-5(2,4-pd)(7)(2,4-Hpd) are present. The zirconium complex is isolated as an adduct, [Zr(2,4-pd)(2)](2)center dot(2,4-H(2)pd). The pentanediolates decompose on heating to form Al2O3 and ZrO2. Unlike the mononuclear Al(acac)(3) and Zr(acac)(4) derivatives (acac = acetylacetonate), the formation of aggregates with the 2,4-pd ligand suggests that the latter has more coordinative flexibility. The geometries of several model aluminum complexes with oxygen donor ligands were studied with density functional theory methods. The optimized structures were used with the gauge, including atomic orbital (GIAO) method to calculate their Al-27 NMR magnetic shielding values for comparison with experiment.