Dearomatization of the PCP Pincer Ligand in a ReV Oxo Complex. Issue 52 (19th August 2018)

• Record Type: Journal Article
• Authors: Kosanovich, Alex J.; Komatsu, Christopher H.; Bhuvanesh, Nattamai; Pérez, Lisa M.; Ozerov, Oleg V.
• Is Part Of: Chemistry. Volume 24:Issue 52(2018)
• Page Start: 13754
• Page End: 13757
• Publication Date: 2018-08-19
• Subjects: cycloaddition -- dearomatization -- PCP ligands -- pincer ligands -- rhenium; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201802589
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A high‐valent, rhenium(V) oxo complex (PCP)ReOCl2 (1 ; PCP=bis(2, 6‐di‐tert‐butylphosphinomethyl)phenyl) undergoes a deprotonation and "dearomatization" upon treatment with LiN(SiMe3 )2 to give (P*CP)ReOCl (2 a ), in which Re is bound to a new dianionic P*CP ligand. Compound2 a was studied spectroscopically, structurally, and computationally and was determined to have non‐negligible Re=C multiple bond character, leading to its formulation as a new pseudo‐carbenoid species. Reaction of2 a or its iodo analogue (P*CP)ReOI (2 b ) with CO2 provided access to (PCP)ReOX(CO2 ) (X=Cl or I, 3 a/b ), the product of 1, 3‐cycloaddition and C−C bond formation. Abstract : Magic pincers : The (2, 6‐diphosphinomethyl)phenyl PCP ligand is one of the most commonly used pincer ligand type. Its isoelectronic analogues, pyridine‐based PNP pincers, display rich chemistry arising from the reversible deprotonation of the benzylic positions in metal complexes. The manuscript describes the first example of clean deprotonation of a PCP ligand, in a Re V oxo complex, its structure, and reactivity with CO2 (see scheme).