Aluminum Complexes Based on Tridentate Amidoalkoxide NNO-Ligands: Synthesis, Structure, and Properties

Publication date: 15 November 2018Source: Journal of Organometallic Chemistry, Volume 875Author(s): Kirill V. Zaitsev, Valeriy S. Cherepakhin, Alexander Zherebker, Alexey Kononikhin, Eugene Nikolaev, Andrei V. ChurakovAbstractA series of novel NNO-type ligands 12a-17a, LH2, R1N(CH2CH2NHTs)CHR2CR3R4OH (R1 = Bn, R3 = R4 = H; R2 = H (12a), R2= (S)-Ph (13a), R2= (S)-Bn (14a), R2= (S)-i-Bu (15a); R1 = R2= (R)-Me, R3 = H, R4= (S)-Ph (16a); R1 = Bn, R2= (S)-i-Bu, R3 = R4 = Ph (17a)) was obtained; the ligands LH2 feature various degree of substitution, steric bulkiness, and chirality. Treatment of 11a (R1 = Me, R2 = R3 = R4 = H), 12a-17a, and 18a (R1 = Me, R2 = H, R3 = R4 = Ph) with AlMe3 afforded the complexes 11b-18b, [LAlMe]n (n = 1, 2). It was demonstrated that the structure of the ligand determines the monomeric (16b-18b, R3, R4 = Ph) or dimeric (11b-15b, R3 = R4 = H) structure of the complexes. The discussion of the stereochemical consequences caused by dimerization and chirality of the ligands is performed. The molecular structures of dimeric 11b, 12b, 15b, and monomeric 17b were studied by single-crystal X-ray diffraction. Complexes 11b, 12b, 14b, and 17b are active initiators in ring-opening polymerization of l-lactide in the absence of alcohol. Furthermore, 11b-13b, 17b, and 18b demonstrate an outstanding catalytic activity and selectivity in alcoholysis of l-lactide to give (S,S)-methyl lac...

Source: Journal of Organometallic Chemistry - September 7, 2018 Category: Chemistry Source Type: research