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Aluminum Complexes of Octahydrophenanthroline‐Based Salophan Ligands: Coordination Chemistry and Activity in the Ring‐Opening Polymerization of Lactide
Author(s) -
Rosen Tomer,
Goldberg Israel,
Kol Moshe
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201801120
Subject(s) - chemistry , ligand (biochemistry) , reactivity (psychology) , lactide , polymerization , benzyl alcohol , ring (chemistry) , coordination complex , yield (engineering) , ring opening polymerization , medicinal chemistry , stereochemistry , polymer chemistry , organic chemistry , catalysis , metal , polymer , medicine , biochemistry , materials science , alternative medicine , receptor , pathology , metallurgy
Salophan ligands featuring the octahydrophenanthroline core are described for the first time. Two ligand precursors featuring either di‐ tert ‐butylphenolate or dichlorophenolate were prepared by 1,10‐phenanthroline hydrogenation followed by reaction with bromomethyl‐substituted phenols. The ligand precursors react with AlMe 3 to give the [{ONNO}Al‐Me]‐type complexes as single stereoisomers of averaged C s ‐symmetry on the NMR timescale. The reactivity of the methylaluminum complexes depends strongly on the phenolate substituents: The complex of the bulky ligand is inert towards alcohols and inactive in the ring‐opening polymerization of rac ‐LA, whereas the complex of the non‐bulky ligand reacts readily with benzyl alcohol to yield the corresponding [{ONNO}Al‐OBn] complex, which polymerizes rac ‐LA to give isotactically inclined PLA.