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UID:20250928T215703EDT-6089jwC0xt@132.216.98.100
DTSTAMP:20250929T015703Z
DESCRIPTION:~A host•guest complex between cucurbit[7]uril (CB[7] and bisqua
 ternary diamantane diaminium salt\, diam-4\,9-di(NMe3I) 1\, was studied by
  1H NMR spectroscopy and X-ray crystallography. 1H NMR competition experim
 ents revealed that CB[7]/1 is among the tightest monovalent non-covalent c
 omplexes ever reported in water with Ka = 7.2 × 1017 M-1 in pure D2O and 2
 .1 × 1015 M-1 in 50 mM NaO2CCD3 buffered D2O. The impetus for this synthes
 is were previously reported X-ray crystallographic investigations of CB[7]
  with adamantane ammonium ions. 'Crystal structure based molecular design 
 suggested that each of the two cations of a new i-symmetry diamantane diam
 inium guest would simultaneously interact with a different portal. The cry
 stal structure of CB[7]/1 allowed us to identify some of the structural fe
 atures responsible for the ultratight binding including the distance betwe
 en the NMe3+ groups of 1 (7.78 Å) which allows it to establish 14 optimal 
 ion-dipole interactions with CB[7]\, the complementarity of the convex van
  der Waals surface contours of 1 with the corresponding concave surfaces o
 f CB[7]\, desolvation of the C=O portals within the CB[7]/1 complex\, and 
 the co-linearity of the C7-axis of CB[7] with the N+...N+ line in 1.\n	The 
 induced fit principle is involved in the binding process. As part of the d
 esign process (using published and in-house) crystal structures\, ΔΔit bec
 ame apparent that primary ammonium guests would tilt towards the portal wa
 lls in order to generate hydrogen-bonds with a very limited number of port
 al carbonyl oxygens. On the other hand\, quaternary ammonium guests underg
 o +N-CH3….–.δO=C and +N-CquatCH2….–.δO=C electrostatic interactions with a
 ll the binding sites of the host.\n
DTSTART:20160509T160000Z
DTEND:20160509T173000Z
LOCATION:Room 112\, Maass Chemistry Building\, CA\, QC\, Montreal\, H3A 0B8
 \, 801 rue Sherbrooke Ouest
SUMMARY:Seminar by Prof. Robert Glaser: A Perfect Pair - Cucurbit[7]uril /D
 iamantane Guest with an Attomolar Dissociation Constant
URL:/chemistry/channels/event/seminar-prof-robert-glas
 er-perfect-pair-cucurbit7uril-diamantane-guest-attomolar-dissociation-2606
 95
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