Monomeric Alkylaluminum Complexes (dpp-BIAN)AlR2 (R = Me, Et, iBu) Supported by the Rigid Chelating Radical-Anionic 1,2-Bis[(2,6-diisopropylphenyl)imino]acenaphthene Ligand (dpp-BIAN)

Abstract

Me2AlCl, Et2AlBr, and iBu2AlCl react with (dpp-BIAN)Na (dpp-BIAN = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) in Et2O to give the dialkylaluminum complexes (dpp-BIAN)AlR2 (R = Me (1), Et (2), iBu (3)). Compounds 1−3 have been characterized by elemental analysis, IR and ESR spectroscopy, and X-ray crystal structure analysis. In the molecules of 1−3 the Al atoms are tetrahedrally coordinated by two alkyl groups and the two N atoms of the dpp-BIAN ligand. The ESR spectra of the complexes prove the radical character of the dpp-BIAN ligand and show a hyperfine structure due to the coupling of the unpaired electron with the 14N, 27Al, and 1H nuclei.