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Synthesis, Characterisation of Carbon‐Bridged (Diphenolato)lanthanide Complexes and Their Catalytic Activity for Diels–Alder Reactions
Author(s) -
Xu Xiaoping,
Ma Mengtao,
Yao Yingming,
Zhang Yong,
Shen Qi
Publication year - 2005
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200400519
Subject(s) - lanthanide , chemistry , cyclopentadiene , ligand (biochemistry) , medicinal chemistry , octahedral molecular geometry , anhydrous , trigonal bipyramidal molecular geometry , crystal structure , catalysis , octahedron , stereochemistry , crystallography , ion , organic chemistry , biochemistry , receptor
The synthesis and structures of new lanthanide complexes supported by the carbon‐bridged diphenolato ligand 2,2′‐methylenebis(6‐ tert ‐butyl‐4‐methylphenolato) (MBMP 2– ) are described. Reactions of anhydrous lanthanide trichlorides with Na 2 MBMP in a 1:2 molar ratio in THF at room temperature afforded the corresponding “ate” (diphenolato)lanthanide complexes [(THF) n Ln(MBMP) 2 Na(THF) 2 ] [Ln = Nd ( 1 ), Sm ( 2 ), n = 2; Ln = Yb, n = 1 ( 3 )]. Recrystallisation of complexes 1 – 3 from toluene in the presence of DME gave the discrete ion‐pair complexes [(MBMP) 2 Ln(THF) 2 ][Na(DME) 2 (THF) 2 ] [Ln = Nd ( 4 ), Sm ( 5 ), Yb ( 6 )]. These complexes have been fully characterised. The single‐crystal structural analyses of 1 , 3 and 6 revealed that the coordination geometries of the lanthanide ions can be best described as distorted octahedral in complexes 1 and 6 and distorted trigonal‐bipyramidal in complex 3 . It was found that these lanthanide complexes are able to act as Lewis acids to catalyse the Diels–Alder reactions of cyclopentadiene with substituted dienophiles with good activity and stereoselectivity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)