Modeling competitive guest binding to β-cyclodextrin molecular printboards

D. Thompson, J. A. Larsson

Research output: Contribution to journalArticlepeer-review

Abstract

Anchoring of functionalized guest molecules to self-assembled monolayers (SAMs) is key to the development of molecular printboards for nanopatterning. One very promising system involves guest binding to immobilized β-cyclodextrin (β-CD) hosts, with guest:host recognition facilitated by a hydrophobic interaction between uncharged anchor groups on the guest molecule and β-CD hosts self-assembled at gold surfaces. We use molecular dynamics free energy (MDFE) simulations to describe the specificity of guest:β-CD association. We find good agreement with experimental thermodynamic measurements for binding enthalpy differences between three commonly used phenyl guests: benzene, toluene, and t-butylbenzene. van der Waals interaction with the inside of the host cavity accounts for almost all of the net stabilization of the larger phenyl guests in β-CD. Partial and full methylation of the secondary rim of β-CD decreases host rigidity and significantly impairs binding of both phenyl and larger adamantane guest molecules. The β-CD cavity is also very intolerant of guest charging, penalizing the oxidized state of ferrocene by at least 7 kcal/mol. β-CD hence expresses moderate specificity toward uncharged organic guest molecules by van der Waals recognition, with a much higher specificity calculated for electrostatic recognition of organometallic guests.

Original languageEnglish
Pages (from-to)16640-16645
Number of pages6
JournalJournal of Physical Chemistry B
Volume110
Issue number33
DOIs
Publication statusPublished - 24 Aug 2006

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