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Different coordination modes of trans ‐2‐{[(2‐methoxyphenyl)imino]methyl}phenoxide in rare‐earth complexes: influence of the metal cation radius and the number of ligands on steric congestion and ligand coordination modes
Author(s) -
Roitershtein Dmitrii M.,
Minashina Kseniya I.,
Minyaev Mikhail E.,
Ananyev Ivan V.,
Lyssenko Konstantin A.,
Tavtorkin Alexander N.,
Nifant'ev Ilya E.
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/s2053229618012421
Subject(s) - chemistry , tetrahydrofuran , medicinal chemistry , steric effects , ionic radius , schiff base , methanol , lanthanum , metal , crystal structure , tris , stereochemistry , ion , inorganic chemistry , crystallography , organic chemistry , biochemistry , solvent
A simple and effective synthetic route to homo‐ and heteroleptic rare‐earth (Ln = Y, La and Nd) complexes with a tridentate Schiff base anion has been demonstrated using exchange reactions of rare‐earth chlorides with in‐situ ‐generated sodium ( E )‐2‐{[(2‐methoxyphenyl)imino]methyl}phenoxide in different molar ratios in absolute methanol. Five crystal structures have been determined and studied, namely tris(2‐{[(2‐methoxyphenyl)imino]methyl}phenolato‐κ 3 O 1 , N , O 2 )lanthanum, [La(C 14 H 12 NO 2 ) 3 ], ( 1 ), tris(2‐{[(2‐methoxyphenyl)imino]methyl}phenolato‐κ 3 O 1 , N , O 2 )neodymium tetrahydrofuran disolvate, [La(C 14 H 12 NO 2 ) 3 ]·2C 4 H 8 O, ( 2 )·2THF, tris(2‐{[(2‐methoxyphenyl)imino]methyl}phenolato)‐κ 3 O 1 , N , O 2 ;κ 3 O 1 , N , O 2 ;κ 2 N , O 1 ‐yttrium, [Y(C 14 H 12 NO 2 ) 3 ], ( 3 ), dichlorido‐1κ Cl ,2κ Cl ‐μ‐methanolato‐1:2κ 2 O : O ‐methanol‐2κ O ‐(μ‐2‐{[(2‐methoxyphenyl)imino]methyl}phenolato‐1κ 3 O 1 , N , O 2 :2κ O 1 )bis(2‐{[(2‐methoxyphenyl)imino]methyl}phenolato)‐1κ 3 O 1 , N , O 2 ;2κ 3 O 1 , N , O 2 ‐diyttrium–tetrahydrofuran–methanol (1/1/1), [Y 2 (C 14 H 12 NO 2 ) 3 (CH 3 O)Cl 2 (CH 4 O)]·CH 4 O·C 4 H 8 O, ( 4 )·MeOH·THF, and bis(μ‐2‐{[(2‐methoxyphenyl)imino]methyl}phenolato‐1κ 3 O 1 , N , O 2 :2κ O 1 )bis(2‐{[(2‐methoxyphenyl)imino]methyl}phenolato‐2κ 3 O 1 , N , O 2 )sodiumyttrium chloroform disolvate, [NaY(C 14 H 12 NO 2 ) 4 ]·2CHCl 3 , ( 5 )·2CHCl 3 . Structural peculiarities of homoleptic tris(iminophenoxide)s ( 1 )–( 3 ), binuclear tris(iminophenoxide) ( 4 ) and homoleptic ate tetrakis(iminophenoxide) ( 5 ) are discussed. The nonflat Schiff base ligand displays μ 2 ‐κ 3 O 1 , N , O 2 :κ O 1 bridging, and κ 3 O 1 , N , O 2 and κ 2 N , O 1 terminal coordination modes, depending on steric congestion, which in turn depends on the ionic radii of the rare‐earth metals and the number of coordinated ligands. It has been demonstrated that interligand dihedral angles of the phenoxide ligand are convenient for comparing steric hindrance in complexes. ( 4 )·MeOH has a flat Y 2 O 2 rhomboid core and exhibits both inter‐ and intramolecular MeO—H…Cl hydrogen bonding. Catalytic systems based on complexes ( 1 )–( 3 ) and ( 5 ) have demonstrated medium catalytic performance in acrylonitrile polymerization, providing polyacrylonitrile samples with narrow polydispersity.