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On/off fluorescence emission induced by encapsulation, exchange and reversible encapsulation of a BODIPY-guest in self-assembled organometallic cages.
- Source :
- Dalton Transactions: An International Journal of Inorganic Chemistry; 6/7/2019, Vol. 48 Issue 21, p7236-7241, 6p
- Publication Year :
- 2019
-
Abstract
- A dynamic guest-binding study of BODIPY-derivative 3 (3 = 1,3,5,7,8-pentamethyl-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) with two Cp*Rh<superscript>III</superscript>-based organometallic cages [Cp*<subscript>6</subscript>Rh<subscript>6</subscript>(μ-CA)<subscript>3</subscript>(tpt)<subscript>2</subscript>](OTf)<subscript>6</subscript>1 (H<subscript>2</subscript>CA = chloranilic acid, tpt = 2,4,6-tripyridyl-1,3,5-triazine) and [Cp*<subscript>6</subscript>Rh<subscript>6</subscript>(μ-DHNA)<subscript>3</subscript>(tpt)<subscript>2</subscript>](OTf)<subscript>6</subscript>2 (H<subscript>2</subscript>DHNA = 6,11-dihydroxynaphthacene-5,12-dione) have been demonstrated. While guest 3 displays a strong green fluorescence emission, the host–guest complexes 3⊂1 and 3⊂2 exhibit almost no emission. However, fluorescence emission can be again ‘turned on’ by adding coronene (4) or pyrene (5) into the solution of 3⊂1 and 3⊂2. Guests 4 and 5 show stronger binding affinities toward the organometallic cages 1 and 2 due to the strong electrostatic interactions between the electron-rich guest and electron-deficient tpt resulting in the displacement of 3 by 4 or 5, which eventually helps the fluorescence enhancement. Further guest-binding studies using a Job's plot experiment illustrate the formation of discrete 1 : 1 host–guest complexes which are also supported by <superscript>1</superscript>H NMR spectroscopy and ESI mass spectrometry. The anion-exchange study with sodium chloride reveals that the chloride ion can effectively disassemble the host frameworks of 1 and 2 releasing the fluorescent guest 3 which can be again encapsulated into the cavity of reassembled cages promoted by the addition of silver triflate. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 14779226
- Volume :
- 48
- Issue :
- 21
- Database :
- Complementary Index
- Journal :
- Dalton Transactions: An International Journal of Inorganic Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 136691818
- Full Text :
- https://doi.org/10.1039/c8dt05103h