Working Paper
Authors
- Anna Kataki-Anastasakou ,
- Jonathan C. Axtell ,
- Selena Hernandez ,
- RafalM. Dziedzic ,
- Gary J. Balaich ,
- Arnold L. Rheingold ,
- Alexander Spokoyny ,
- Ellen Sletten
University of California-Los Angeles
Abstract
High affinity guest have been reported for the macrocyclic host cucurbit[7]uril (CB[7]), enabling widespread applications, but preventing CB[7] materials from being returned to their guest-free state for reuse. Here we present polyhedral boron clusters (carboranes) as strongly-binding, yet easily removable, guests for CB[7]. Aided by a Pd-catalyzed coupling of an azide anion, we prepared boron-functionalized 9-amino and 9-ammonium modified ortho-carboranes that bind to CB[7] with a Ka=1010 M-1. Upon treatment with base, the ortho-carboranes readily undergo deboronation to yield anionic nido-carborane, a poor guest of CB[7], facilitating recovery of guest-free CB[7]. We showcase the utility of the modified ortho-carborane guest by recycling a CB[7]-functionalized resin. With this report, we introduce stimuli-responsive decomplexation as an additional consideration in the design of high affinity host-guest complexes.
Content
![Thumbnail image of CB[7]-carborane_ChemRxiv_final.pdf](https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74f13842e6577a5db3797/largeThumb/carborane-guests-for-cucurbit-7-uril-facilitate-strong-binding-and-on-demand-removal.jpg)