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Ring‐Size‐Modulated Reactivity of Putative Dicobalt‐Bridging Nitrides: C−H Activation versus Phosphinimide Formation
Author(s) -
Cui Peng,
Wang Qiuran,
McCollom Samuel P.,
Manor Brian C.,
Carroll Patrick J.,
Tomson Neil C.
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201708966
Subject(s) - chemistry , azide , reactivity (psychology) , thermal decomposition , alkyl , linker , ligand (biochemistry) , amination , methylene , medicinal chemistry , stereochemistry , bridging ligand , crystallography , crystal structure , organic chemistry , catalysis , medicine , biochemistry , alternative medicine , receptor , pathology , computer science , operating system
Abstract Dicobalt complexes supported by flexible macrocyclic ligands were used to target the generation of the bridging nitrido species [( n PDI 2 )Co 2 (μ‐N)(PMe 3 ) 2 ] 3+ (PDI=2,6‐pyridyldiimine; n =2, 3, corresponding to the number of catenated methylene units between imino nitrogen atoms). Depending on the size of the macrocycle and the reaction conditions (solution versus solid‐state), the thermolysis of azide precursors yielded bridging phosphinimido [( 2 PDI 2 )Co 2 (μ‐NPMe 3 )(PMe 3 ) 2 ] 3+ , amido [( n PDI 2 )Co 2 (μ‐NH 2 )(PMe 3 ) 2 ] 3+ ( n =2, 3), and C−H amination [( 3 PDI 2 *‐μ‐NH)Co 2 (PMe 3 ) 2 ] 3+ products. All results are consistent with the initial formation of [( n PDI 2 )Co 2 (μ‐N)(PMe 3 ) 2 ] 3+ , followed by 1) PMe 3 attack on the nitride, 2) net hydrogen‐atom transfer to form N−H bonds, or 3) C−H amination of the alkyl linker of the n PDI 2 ligand.