Encapsulation of tetramethylphosphonium cations

Ngong Kodiah Beyeh, Arto Valkonen, Kari Rissanen

Research output: Contribution to journalArticleScientificpeer-review

19 Citations (Scopus)

Abstract

The weak interactions and capsule formation of tetramethylphosphonium (TMP) cation with resorcinarenes 1 and 2 and the corresponding pyrogallarenes 3 and 4 were studied in the solid state by single-crystal X-ray diffraction, in solution by NMR and in the gas phase by mass spectrometry. In methanol-d 4, the NMR titration studies reveal that the association constants for the 1:1 complexes of TMP@3 and TMP@4 are much higher (TMP@4:390 ± 37 M− 1) than for the corresponding TMP@1 and TMP@2 (TMP@2:130 ± 10 M− 1) complexes. In the gas phase both monomeric 1:1 TMP@1-TMP@4 complexes as well as the dimeric 1:2 capsule complexes, TMP@1 2–TMP@4 2 were observed. The 1:1:2 molar mixtures of 1:2:TMP or 3:4:TMP resulted in homo- and heterocapsules TMP@1 2, TMP@1+2 and TMP@2 2, with the expected statistical 1:2:1 ratio. Using the 1:1:2 ratio of 1:3:TMP, 1:4:TMP, 2:3:TMP or 2:4:TMP showed a marked prefence to the homopyrogallarene capsules TMP@3 2 and TMP@4 2, thus supporting the stronger complexation of TMP with 3 and 4 as observed in solution. The X-ray structures 1 confirmed the dimeric capsular structures with only minor structural differences to the corresponding tetramethylammonium (TMA) capsules reported earlier.
Original languageEnglish
Pages (from-to)142-148
JournalSupramolecular Chemistry
Volume21
Issue number1-2
DOIs
Publication statusPublished - Dec 2009
MoE publication typeA1 Journal article-refereed

Keywords

  • supramolecular chemistry
  • resorcinarenes
  • capsules
  • X-ray crystallography
  • mass spectrometry

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