A Strategy to Control the Reactivation of Frustrated Lewis Pairs from Shelf‐Stable Carbene Borane Complexes. Issue 40 (28th August 2015)

• Record Type: Journal Article
• Authors: Hoshimoto, Yoichi; Kinoshita, Takuya; Ohashi, Masato; Ogoshi, Sensuke
• Is Part Of: Angewandte Chemie international edition. Volume 54:Issue 40(2015)
• Page Start: 11666
• Page End: 11671
• Publication Date: 2015-08-28
• Subjects: frustrated Lewis pairs -- hydrogenation -- N‐heterocyclic carbenes -- phosphine oxides; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201505974
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: N‐Phosphine oxide substituted imidazolylidenes (PoxIms) have been synthesized and fully characterized. These species can undergo significant changes to the spatial environment surrounding their carbene center through rotation of the phosphine oxide moiety. Either classical Lewis adducts (CLAs) or frustrated Lewis pairs (FLPs) are thus formed with B(C6 F5 )3 depending on the orientation of the phosphine oxide group. A strategy to reactivate FLPs from CLAs by exploiting molecular motions that are responsive to external stimuli has therefore been developed. The reactivation conditions were successfully controlled by tuning the strain in the PoxIm–B(C6 F5 )3 complexes so that reactivation only occurred above ambient temperature. Abstract : Frustration under control : Imidazolylidenes with a phosphine oxide substituent on one of the nitrogen atoms can undergo drastic changes to the spatial environment surrounding their carbene center through rotation of the phosphine oxide moiety. Depending on the orientation of this group, either classical Lewis adducts or frustrated Lewis pairs (FLPs) are formed upon addition of B(C6 F5 )3 .