Concurrent Stabilization of π‐Donor and π‐Acceptor Ligands in Aromatized and Dearomatized Pincer [(PNN)Re(CO)(O)2] Complexes |
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| Authors: | Michael G Mazzotta Dr Kothanda Rama Pichaandi Dr Phillip E Fanwick Prof?Dr Mahdi M Abu‐Omar |
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| Institution: | 1. Department of Chemistry, Purdue University, West Lafayette, IN 47907 (USA) http://www.chem.purdue.edu/abu‐omar/;2. School of Chemical Engineering, Purdue University, West Lafayette, IN 47907 (USA) |
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| Abstract: | 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 ), tBuNC ( b ), or (2,6‐Me2)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 dxy orbital of rhenium, the π orbital of the oxo ligands, and the π* orbital of CO/isocyanide. |
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| Keywords: | carbon monoxide isocyanide ligands oxo ligands pincer ligands rhenium |
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