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Title: Mapping C−H⋅⋅⋅M Interactions in Confined Spaces: (α‐ICyD Me )Au, Ag, Cu Complexes Reveal “Contra‐electrostatic H Bonds” Masquerading as Anagostic Interactions**
Abstract

What happens when a C−H bond is forced to interact with unpaired pairs of electrons at a positively charged metal? Such interactions can be considered as “contra‐electrostatic” H‐bonds, which combine the familiar orbital interaction pattern characteristic for the covalent contribution to the conventional H‐bonding with an unusual contra‐electrostatic component. While electrostatics is strongly stabilizing component in the conventional C−H⋅⋅⋅X bonds where X is an electronegative main group element, it is destabilizing in the C−H⋅⋅⋅M contacts when M is Au(I), Ag(I), or Cu(I) of NHC−M−Cl systems. Such remarkable C−H⋅⋅⋅M interaction became experimentally accessible within (α‐ICyDMe)MCl, NHC‐Metal complexes embedded into cyclodextrins. Computational analysis of the model systems suggests that the overall interaction energies are relatively insensitive to moderate variations in the directionality of interaction between a C−H bond and the metal center, indicating stereoelectronic promiscuity of fully filled set ofd‐orbitals. A combination of experimental and computational data demonstrates that metal encapsulation inside the cyclodextrin cavity forces the C−H bond to point toward the metal, and reveals a still attractive “contra‐electrostatic” H‐bonding interaction.

 
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Award ID(s):
1800329
NSF-PAR ID:
10226913
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Chemistry – A European Journal
Volume:
27
Issue:
31
ISSN:
0947-6539
Page Range / eLocation ID:
p. 8127-8142
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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