Premium
A Comparative Study on the Reactivity of Tris‐β‐Diketiminate Ytterbium Complexes: Steric Effect of β‐Diketiminato Ligands
Author(s) -
Jiao Rui,
Xue Mingqiang,
Shen Xiaodong,
Zhang Yong,
Yao Yingming,
Shen Qi
Publication year - 2010
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.201000156
Subject(s) - chemistry , steric effects , ytterbium , reactivity (psychology) , tris , medicinal chemistry , polymerization , catalysis , ligand (biochemistry) , polymer chemistry , stereochemistry , organic chemistry , polymer , biochemistry , physics , alternative medicine , receptor , medicine , optoelectronics , doping , pathology
A series of tris‐β‐diketiminate ytterbium complexes with the general formula [YbL 3 ] {L = [N(C 6 H 5 )C(Me)] 2 CH – , L H ( 1 ); [N(4‐MeC 6 H 4 )C(Me)] 2 CH – , L 4‐Me ( 2 ), and [N(2‐MeC 6 H 4 )C(Me)] 2 CH – , L 2‐Me ( 3 )} were synthesized and structurally characterized. All complexes have longer Yb–N bond lengths than other YbL‐containing derivatives, and complex 3 has the longest average Yb–N bond length. A comparative study on the reactivity of complexes 1 – 3 revealed that complex 3 was a highly active catalyst for the polymerization of ϵ‐caprolactone and L ‐lactide, as well as for the addition of amines to carbodiimides, whereas both complexes 1 and 2 were almost inactive under the same conditions. The active sequence is consistent with the distance of the Yb–N bond, which is reflected in the sterically induced activation of the bulky tris‐β‐diketiminate ytterbium complexes.