Scandium and yttrium complexes of an hybrid phenoxy-amidopyridinate ligand. Use in ROP of racemic lactide

• Published in: Journal of organometallic chemistry 2016-11, Vol.823, p.34-39
• Main Authors: El Haj Hassan, Jad, Radkov, Vasily, Dorcet, Vincent, Carpentier, Jean-François, Kirillov, Evgueni
• Format: Article
• Language: English
• Subjects: Alkyl complexes; Chemical Sciences; Cyclic esters; Group 3 metals; Nitrogen-based ligands; ROP; Structure elucidation
• ISSN: 0022-328X; 1872-8561; 0022-328X
• DOI: 10.1016/j.jorganchem.2016.09.014

The new multidentate hybrid phenol-aminopyridine proligand {NMe2NNMe2CiPr2O}H2 (1-H2) was prepared and used in σ-bond metathesis reactions with the trialkyl precursors M(CH2SiMe3)3(THF)2 (M = Sc, Y). These reactions afforded cleanly the corresponding alkyl complexes {NMe2NNMe2CiPr2O}M(CH2SiMe3)(THF) (M = Sc (1-Sc), Y (1-Y)), which were characterized by NMR spectroscopy and microanalysis. Upon crystallization, 1-Sc disproportionates to form the bis(ligand) complex 2-Sc which was isolated and characterized by X-ray crystallography. Complexes 1-Sc and 1-Y were used as initiators in the ring-opening polymerization (ROP) of racemic lactide, alone or in combination with iPrOH, to give atactic PLAs with controlled molecular weights. New alkyl group 3 metal complexes based on a hybrid phenoxy-amidopyridinate ligand have been prepared and used in ROP of racemic lactide. [Display omitted] •Synthesis of the new multidentate hybrid phenol-aminopyridine proligand.•Scandium and yttrium alkyls were prepared and characterized.•ROP of racemic lactide afforded atactic PLAs with controlled molecular weights.