Premium
Zinc Complexes of Piperazinyl‐Derived Aminephenolate Ligands: Synthesis, Characterization and Ring–Opening Polymerization Activity
Author(s) -
Ikpo Nduka,
Saunders Lisa N.,
Walsh Jillian L.,
Smith Jennifer M. B.,
Dawe Louise N.,
Kerton Francesca M.
Publication year - 2011
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.201100703
Subject(s) - chemistry , cyclohexene oxide , bimetallic strip , reactivity (psychology) , medicinal chemistry , polymerization , zinc , ring opening polymerization , ligand (biochemistry) , pyridine , diethylzinc , alkoxide , cyclohexene , catalysis , polymer chemistry , stereochemistry , organic chemistry , enantioselective synthesis , polymer , medicine , biochemistry , alternative medicine , receptor , pathology
A series of zinc complexes was prepared from 4,6‐disubstituted (R,R′) o ‐[(4‐methyl‐1‐piperazinyl)methyl]phenols ([ONN R′,R ]H) and characterized by elemental analysis, 1 H and 13 C{ 1 H} NMR spectroscopy, and X‐ray crystallography. Reaction of these products with diethylzinc gave Zn[ONN t Bu, t Bu ] 2 ( 1 ) as a monometallic complex and {[μ‐ONN R′,R ]ZnEt} 2 [R′ = Me, R = t Bu, ( 2 ); R′ = R = t Bu ( 3 ); R′ = R = t Am ( 4 )] bimetallic species that have distorted tetrahedral environments about the Zn centres. Reaction of 3 and 4 with alcohols gave {[ONN t Am, t Am ]Zn(μ‐OR″)} 2 [R″ = Bn ( 5 ); R″ = Et ( 6 )] bimetallic species in which the Zn centres are bridged by benzyl alkoxide and ethoxide groups, respectively. A morpholinyl derived ligand was also synthesized and characterized ( L4 H), and its 1:1 stoichiometric reaction with ZnEt 2 resulted in complex 7 , {[μ‐ONO t Bu, t Bu ]ZnEt} 2 . The reactivity of complexes 2 – 7 in the ring‐opening polymerization of rac ‐lactide (LA) and ϵ‐caprolactone (ϵ‐CL) was studied. Reactions of carbon dioxide with cyclohexene oxide in the presence of 6 or 7 /ROH (R = Bn, Et) afforded cyclohexene carbonate.