External and Internal Guest Binding of a Highly Charged Supramolecular Host in Water: Deconvoluting the Very Different Thermodynamics
NMR, UV-vis and isothermal titration calorimetry (ITC) measurements probe different aspects of competing host-guest equilibria as simple alkylammonium guest molecules interact with both the exterior (ion-association) and interior (encapsulation) of the [Ga{sub 4}L{sub 6}]{sup 12-} supramolecular assembly in water. Data obtained by each independent technique measure different components of the host-guest equilibria and only when analyzed together does a complete picture of the solution thermodynamics emerge. Striking differences between the internal and external guest binding are found. External binding is enthalpy driven and mainly due to attractive interactions between the guests and the exterior surface of the assembly while encapsulation is entropy driven as a result of desolvation and release of solvent molecules from the host cavity.
- Research Organization:
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
- Sponsoring Organization:
- Chemical Sciences Division
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1001081
- Report Number(s):
- LBNL-3415E
- Journal Information:
- Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Vol. 132; ISSN JACSAT; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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