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A Homochiral {Co ΙΙ 16 Co ΙΙΙ 4 } Supertetrahedral T 4 Cluster from a Racemic Ligand with Ferromagnetic Behavior and High Photocatalytic Activity
Author(s) -
Du Wei,
Bai YueLing,
Yin Xiuping,
Fang Jianhui,
Zhu Shourong,
Tao Jun
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201700797
Subject(s) - cobalt , enantiopure drug , chemistry , ligand (biochemistry) , enantiomer , crystallography , aqueous solution , cluster (spacecraft) , crystallization , stereochemistry , catalysis , medicinal chemistry , inorganic chemistry , enantioselective synthesis , organic chemistry , biochemistry , receptor , computer science , programming language
A homochiral mixed‐valence cobalt cluster [Co ΙΙ 16 Co ΙΙΙ 4 (μ 6 ‐O) 4 (μ 3 ‐OH) 12 (S‐bme) 12 (OAc) 6 ]Cl 6 ⋅5 CH 3 OH⋅18 H 2 O ( 1 , Hbme=1H‐(benzimidazol‐2‐yl)ethanol) was synthesized from a racemic ligand and three cobalt salts of CoCl 2 ⋅6 H 2 O, Co(Ac) 2 ⋅4 H 2 O and Co(NO 3 ) 2 ⋅6 H 2 O in a DMF/MeOH mixed solvent. The enantioselective coordination occurs when a large excess of cobalt ions added in the solution and only the S ‐configuration of the racemic ligand involved in crystallization. The CD spectra of three crystal samples show identical Cotton signals, indicating the repeatability and the enantiomeric purity of the single crystals. This compound presents a beautiful two‐shell Matryoshka‐type supertetrahedral T 4 cluster constructed by an inner Co ΙΙΙ 4 O 4 cubane and four exterior Co ΙΙ 4 O 4 cubanes bridged by μ 6 ‐O 2− and μ 3 ‐OH − ions. This highest nuclear chiral cobalt cluster is the first example of enantiopure cobalt cluster separated from a racemic ligand and is the largest supertetrahedral cobalt cluster up to now. The magnetic studies reveal it behaves as a ferromagnet. Photocatalytic properties of 1 show high catalytic activities for the degradation of the highly toxic triphenyl dye crystal violet ( CV ) in the presence of H 2 O 2 under visible light in aqueous solution. The degradation rate almost reach 100 % at 45 min and can maintain 98.54 % after 8 cycles.