Supramolecular Assembly of 2,7‐Dimethyldiazapyrenium and Cucurbit[8]uril: A New Fluorescent Host for Detection of Catechol and Dopamine

Abstract

The formation of a highly stable inclusion complex between 2,7-dimethyldiazapyrenium (Me(2)DAP(2+)) and the cucurbit[8]uril host (CB8) was demonstrated by X-ray crystallography; MALDI-TOF mass spectrometry; and (1)H NMR, electronic absorption, and emission spectroscopy. The equilibrium association constant was determined to be 8.9(+/-0.2)x10(5) L mol(-1) from UV-visible data and 8.4(+/-1.5) x 10(5) L mol(-1) from fluorescence data. The Me(2)DAP(2+).CB8 inclusion complex acted as a host to bind compounds containing aromatic pi-donor moieties (D), such as catechol and dopamine. This point was demonstrated by (1)H NMR spectroscopy, and electrochemical and emission measurements. Fluorescence detection of the Me(2)DAP(2+).D.CB8 ternary complexes was evident in aqueous solution and on the surface of silica particles, to which fluorescent diazapyrenium units had been covalently immobilized.

Bindungsmechanismen in supramolekularen Komplexen

“…B. Spermin mit bis zu K = 10 10 m À1 oder Adamantanammoniumderivate mit K > 10 12 m À1 . [20] Ein Ferrocenderivat mit zwei Alkylammoniumgruppen R zeigt mit Cucurbit [7]uril mit K = 3 10 15 m À1 eine Stärke wie der Biotin-StreptavidinKomplex, mit DH = 90 AE 1 kJ mol À1 , bei einem gleichzeitig außergewöhnlich geringen Entropienachteil von TDS nahe null (Schema 1). [21] Dass mit synthetischen Wirtverbindungen neben hohen Affinitäten auch hohe Selektivitäten erzielbar sind, zeigt z.…”

Cucurbit[8]uril/Cucurbit[7]uril Controlled Off/On Fluorescence of the Acridizinium and 9‐Aminoacridizinium Cations in Aqueous Solution

“…[5] CB [7] and CB [8] host molecules have the capacity to encapsulate larger molecules, such as aromatic compounds, [8] ferrocenes, [9] and platinum metal complexes, [10] or more than one guest molecule. [11][12][13][14][15] The confined cavities of CB [7] or CB [8] may catalyze stereoselective photodimerization reactions by orienting two aromatic molecules in close proximity. [11] CB [7] has also been shown to stabilize products and eliminate unwanted side products in photoisomerization processes.…”

Supramolekulare Blockcopolymere mit Cucurbit[8]uril in Wasser

“…10 11 m À2 ) in wässrigen Lö-sungen zu erzielen. [25][26][27] Kim et al haben gezeigt, dass Viologenderivate und Hydroxynaphthaline im Hohlraum von CB [8] stabile Charge-Transfer-Komplexe bilden. [25] Dies eröffnet die Möglichkeit, durch Selbstorganisation kleine Molekülbausteine zahlreiche Architekturen und molekulare Maschinen aufzubauen.…”