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Synthesis and Crystal Structures of an Unexpected Tetranuclear Zinc(II) Complex and a Benzoquinone Compound Derived from Zn II ‐ and Cd II ‐Promoted Reactivity of Schiff Base Ligands
Author(s) -
Yu Bin,
Sun YinXia,
Yang ChengJuan,
Guo JianQiang,
Li Jing
Publication year - 2017
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201700034
Subject(s) - chemistry , salicylaldehyde , oxime , schiff base , reactivity (psychology) , ligand (biochemistry) , medicinal chemistry , bond cleavage , benzoquinone , crystal structure , acetonitrile , stereochemistry , zinc , imine , polymer chemistry , organic chemistry , catalysis , medicine , alternative medicine , pathology , biochemistry , receptor
An unexpected polyhydroxyl‐bridged tetranuclear Zn II complex and a benzoquinone compound derived from metal‐ion promoted reactivity of Schiff base ligands were synthesized and characterized. The reaction of zinc(II) acetate dihydrate with oxime‐type Schiff base ligand HL 1 [HL 1 = 1‐(3‐((3,5‐dibromosalicylaldehyde)amino)phenyl)ethan‐1‐one O ‐benzyl oxime] in methanol, acetone, and acetonitrile resulted in the chemoselective cleavage of the C=N bond of the Schiff base HL 1 , and then the further addition of acetone to two salicylaldehyde molecules derived from cleavage of the C=N bond in situ α,α double aldol reaction promoted by Zn II ions. The newly formed ligands H 4 L 2 coordinate to four Zn II ions forming a defect‐dicubane core structure [Zn II 4 (H 2 L 2 ) 2 (μ 3 ‐OCH 3 ) 2 (μ‐OCH 3 ) 2 (CH 3 OH) 2 ] ( 1 ) bridged exclusively by oxygen‐based ligands. The similar ligand HL 3 [HL 3 = 1‐(3‐((3,5‐dichlorosalicylaldehyde)amino)phenyl)ethan‐1‐one O ‐benzyl oxime)] was employed to react with Cd II acetate dihydrate under the same reaction conditions. No aldol addition occurred but a unexpected benzoquinone compound 2,5‐bis(((3‐(1‐((benzyloxy)imino)ethyl)phenyl)imino)methyl)‐1,4‐benzoquinone ( 2 ) formed. The results provided interesting insights into one‐pot routes involving in situ reactions act as a strategy for obtaining a variety of polymeric/polynuclear complexes which are inconvenient to obtain from directly presynthesizing the ligands.