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Synthesis, Structure, and C–C Cross‐Coupling Activity of (Amine)bis(phenolato)iron(acac) Complexes
Author(s) -
Hasan Kamrul,
Dawe Louise N.,
Kozak Christopher M.
Publication year - 2011
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.201100553
Subject(s) - chemistry , methylene , medicinal chemistry , ligand (biochemistry) , alkyl , amine gas treating , halide , aryl , crystal structure , reagent , coupling reaction , stereochemistry , crystallography , catalysis , inorganic chemistry , organic chemistry , biochemistry , receptor
A series of (amine)bis(phenolato)iron(III)acac complexes has been prepared and characterized. Reaction of Fe(acac) 3 with the diprotonated linear tetradentate proligand N , N′ ‐bis(4,6‐di‐ tert ‐butyl‐2‐methylphenol)‐ N , N′ ‐dimethyl‐1,2‐diaminoethane, H 2 [ L1 ], and tripodal tetradentate ligand precursors dimethylaminoethylamino‐ N , N ‐bis(2‐methylene‐4,6‐di‐ tert ‐butylphenol), H 2 [ L2 ], dimethylaminoethylamino‐ N , N ‐bis(2‐methylene‐4‐methyl‐6‐ tert ‐butylphenol), H 2 [ L3 ], 2‐methoxyethylamino‐ N , N ‐bis(2‐methylene‐4,6‐di‐ tert ‐butylphenol), H 2 [ L4 ], 2‐methoxyethylamino‐ N , N ‐bis(2‐methylene‐4‐methyl‐6‐ tert ‐butylphenol), H 2 [ L5 ], and 2‐methoxyethylamino‐ N , N ‐bis(2‐methylene‐4,6‐dimethylphenol), H 2 [ L6 ], produces the distorted octahedral Fe III complexes [ L1 ]Fe(acac) ( 1 ), [ L2 ]Fe(acac) ( 2 ), [ L3 ]Fe(acac) ( 3 ), [ L4 ]Fe(acac) ( 4 ), [ L5 ]Fe(acac) ( 5 ), and [ L6 ]Fe(acac) ( 6 ). In all of these complexes, the phenolato oxygen atoms are cis ‐oriented. The paramagnetic Fe III complexes 1 – 6 were also characterized by UV/Vis and IR spectroscopy, mass spectrometry, cyclic voltammetry, and magnetic measurements. Single crystal X‐ray molecular structures have been determined for complexes 1 , 2 , 3 , 5 , and the proligand H 2 [ L6 ]. Preliminary investigations of complexes 1 – 6 for catalytic cross‐coupling reactions of aryl Grignard reagents with cyclic and acyclic secondary alkyl halides and benzyl halides were performed. While the activity for cyclohexyl chlorides and bromides was high, cross‐coupling of benzyl halides was moderate and 2‐bromo‐ and 2‐chlorobutane gave poor yields of cross‐coupled product.