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Synthesis of Chiral C 2 ‐Symmetric Bimetallic Zinc Complexes of Amido‐Oxazolinates and Their Application in Copolymerization of CO 2 and Cyclohexene Oxide
Author(s) -
Abbina Srinivas,
Chidara Vamshi K.,
Bian Shi,
Ugrinov Angel,
Du Guodong
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201600581
Subject(s) - cyclohexene oxide , homoleptic , bimetallic strip , catalysis , chemistry , zinc , copolymer , polycarbonate , toluene , polymer chemistry , carbonate , medicinal chemistry , oxide , yield (engineering) , cyclohexene , stereochemistry , organic chemistry , materials science , polymer , metal , metallurgy
Abstract A family of new chiral C 2 symmetric amido‐oxazolinate ligands H 2 L ( 1 a‐1 d ) that are bridged by three different linkers based on m ‐phenylenediamine, 4‐(4’‐aminobenzyl)benzenamine, and 1,8‐diaminoanthracene have been synthesized in high yields (85‐90 %). Treatment of ligands ( 1 a‐1 d ) with two equiv. of Zn[N(SiMe 3 ) 2 ] 2 in dry toluene generated a series of heteroleptic dizinc complexes (L)[ZnN(SiMe 3 ) 2 ] 2 ( 2 a ‐ 2 d ) and reaction of 1 b with one equiv. of Zn[N(SiMe 3 ) 2 ] 2 leads to formation of a homoleptic binuclear zinc complex (L) 2 Zn 2 ( 3 b ) in good yield. Complexes 2 a ‐ 2 d were found to be effective catalysts for asymmetric alternating copolymerization of CO 2 and cyclohexene oxide (CHO). The catalyst 2 a is more active towards polycarbonate formation (78 % carbonate linkages), while the catalyst 2 d generates highly isotactic poly(cyclohexene carbonate) (86 % of m ‐centered tetrads).