Isolation and stabilization of a pheromone in crystalline molecular capsules

Wenchang Xiao, Chunhua Hu, Michael D. Ward

Research output: Contribution to journalArticle

Abstract

The active monomer form of the male-produced pheromone of the Mediterranean fruit fly can be isolated selectively from its equilibrating trimer species by encapsulation within a calixarene pocket built into a hydrogen-bonded framework from guanidinium 4-sulfocalix[4]arene. Encapsulation of the Δ1- pyrroline guest significantly perturbs the assembly of the quasihexagonal two-dimensional guanidinium-sulfonate network of the guest-free framework, to the extent that guanidinium ions are excluded from some sites to accommodate the steric requirements of the guest. Nonetheless, single crystal X-ray diffraction reveals the preservation of a layered structrure in which the calixarene capsules stack in an antiparallel configuration. These observations illustrate that the binding of the pheromone monomer by the calixarene is sufficiently strong to overcome the loss of guanidinium-sulfonate hydrogen bonds, which is corroborated by the strong binding constants measured in solution. The solid-state encapsulation stabilizes the otherwise volatile unstable monomer form, suggesting an effective strategy for the storage, application, and controlled release of an important agricultural adjuvant.

Original languageEnglish (US)
Pages (from-to)3197-3200
Number of pages4
JournalCrystal Growth and Design
Volume13
Issue number7
DOIs
StatePublished - Jul 3 2013

    Fingerprint

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

Cite this