Synthesis and characterization of asymmetric dinuclear aluminum compounds containing sterically hindered heterocyclic β-diketones

Abstract

Reactions of Al(OPri)3 with sterically hindered heterocyclic β-diketones,4-acyl-3-methyl-1-phenyl-2-pyrazolone-5-ones have been carried out in 1:1 molar ratio in toluene to yield asymmetric dimeric compounds [RC(O)C:C(O)N(Ph)N:CCH3]2Al(μ-OPri)2Al(OPri)2 where 1, R=CH3; 2, R=C2H5, 3, R=C6H5; 4, C6H4Cl. These derivatives have been characterized by elemental analysis, molecular weight measurements and probable structure of these compounds have been proposed on the basis of IR, 1H, 13C, 27Al NMR spectroscopies and FAB mass spectrometry. Based on the spectroscopic evidence an asymmetric structure with tetrahedral and octahedral aluminum centers has been proposed for these derivatives.

Keywords

• asymmetric dimeric compounds
• heterocyclic β-diketones
• hexacoordinated aluminum centers
• tetracoordinated aluminum centers