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Phenoxide and alkoxide complexes of Mg, Al and Zn, and their use for the ring‐opening polymerization of ϵ‐caprolactone with initiators of different natures
Author(s) -
Minyaev Mikhail E.,
Nifant'ev Ilya E.,
Shlyakhtin Andrey V.,
Ivchenko Pavel V.,
Lyssenko Konstantin A.
Publication year - 2018
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229618005090
Subject(s) - tetrahydrofuran , chemistry , heteronuclear molecule , alkoxide , dimer , ligand (biochemistry) , ring opening polymerization , crystallography , stereochemistry , medicinal chemistry , polymerization , nuclear magnetic resonance spectroscopy , catalysis , organic chemistry , biochemistry , polymer , receptor , solvent
A new packing polymorph of bis(2,6‐di‐ tert ‐butyl‐4‐methylphenolato‐κ O )bis(tetrahydrofuran‐κ O )magnesium, [Mg(C 15 H 23 O) 2 (C 4 H 8 O) 2 ] or Mg(BHT) 2 (THF) 2 , (BHT is the 2,6‐di‐ tert ‐butyl‐4‐methylphenoxide anion and THF is tetrahydrofuran), ( 1 ), has the same space group ( P 2 1 ) as the previously reported modification [Nifant'ev et al. (2017 d ). Dalton Trans. 46 , 12132–12146], but contains three crystallographically independent molecules instead of one. The structure of ( 1 ) exhibits rotational disorder of the tert ‐butyl groups and positional disorder of a THF ligand. The complex of bis(2,6‐di‐ tert ‐butyl‐4‐methylphenolato‐κ O )bis(μ 2 ‐ethyl glycolato‐κ 2 O , O ′:κ O )dimethyldialuminium, [Al 2 (CH 3 ) 2 (C 4 H 7 O 3 ) 2 (C 15 H 23 O) 2 ] or [(BHT)AlMe(OCH 2 COOEt)] 2 , ( 2 ), is a dimer located on an inversion centre and has an Al 2 O 2 rhomboid core. The 2‐ethoxy‐2‐oxoethanolate ligand (OCH 2 COOEt) displays a μ 2 ‐κ 2 O , O ′:κ O semi‐bridging coordination mode, forming a five‐membered heteronuclear Al–O–C–C–O ring. The same ligand exhibits positional disorder of the terminal methyl group. The redetermined structure of the heptanuclear complex octakis(μ 3 ‐benzyloxo‐κ O :κ O :κ O )hexaethylheptazinc, [Zn 7 (C 2 H 5 ) 6 (C 7 H 7 O) 8 ] or [Zn 7 (OCH 2 Ph) 8 Et 6 ], ( 3 ), possesses a bicubic Zn 7 O 8 core located at an inversion centre and demonstrates positional disorder of one crystallographically independent phenyl group. Cambridge Structural Database surveys are given for complexes structurally analogous to ( 2 ) and ( 3 ). Complexes ( 2 ) and ( 3 ), as well as derivatives of ( 1 ), are of interest as catalysts for the ring‐opening polymerization of ϵ‐caprolactone, and polymerization results are reported.