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Concurrent Stabilization of π‐Donor and π‐Acceptor Ligands in Aromatized and Dearomatized Pincer [(PNN)Re(CO)(O) 2 ] Complexes
Author(s) -
Mazzotta Michael G.,
Pichaandi Kothanda Rama,
Fanwick Phillip E.,
AbuOmar Mahdi M.
Publication year - 2014
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.201403788
Subject(s) - chemistry , pincer movement , ligand (biochemistry) , rhenium , cationic polymerization , acceptor , crystal structure , crystallography , octahedron , natural bond orbital , pincer ligand , stereochemistry , medicinal chemistry , density functional theory , inorganic chemistry , catalysis , polymer chemistry , organic chemistry , computational chemistry , receptor , biochemistry , physics , condensed matter physics
Aromatized cationic [(PNN)Re(π acid)(O) 2 ] + ( 1 ) and dearomatized neutral [(PNN*)Re(π acid)(O) 2 ] ( 2 ) complexes (where π acid=CO ( a ), t BuNC ( b ), or (2,6‐Me 2 )PhNC ( c )), possessing both π‐donor and π‐acceptor ligands, have been synthesized and fully characterized. Reaction of [(PNN)Re(O) 2 ] + ( 4 ) with lithiumhexamethyldisilazide (LiHMDS) yield the dearomatized [(PNN*)Re(O) 2 ] ( 3 ). Complexes 1 and 2 are prepared from the reaction of 4 and 3 , respectively, with CO or isocyanides. Single‐crystal X‐ray structures of 1 a and 1 b show the expected trans ‐dioxo structure, in which the oxo ligands occupy the axial positions and the π‐acidic ligand occupies the equatorial plane in an overall octahedral geometry about the rhenium(V) center. DFT studies revealed the stability of complexes 1 and 2 arises from a π‐backbonding interaction between the d xy orbital of rhenium, the π orbital of the oxo ligands, and the π* orbital of CO/isocyanide.