Jump to main content
Jump to site search

Issue 29, 2012
Previous Article Next Article

Charge-transfer guest interactions in luminescent MOFs: implications for solid-state temperature and environmental sensing

Author affiliations

Abstract

One of the ongoing goals in the field of porous materials is the design and synthesis of materials that possess chemical structures amenable for use in sensing applications. We describe the preparation, luminescence characteristics, and environmental sensing properties of variants of the aluminum-based MOF [Al(OH)(O2C–C10H6–CO2)]. Careful activation of the open framework complex, 1, yielded a dynamic structural transformation to a non-porous form, 2, that exhibited strong inter-linker interactions and red-shifted emission characteristics indicative of dimer formation. We also demonstrate the formation of highly luminescent ground-state charge-transfer (CT) complexes between 1 and the electron-donating amines dimethylamine (DMA) (1a), and N,N-diethylaniline (DEA) (1b), both of which exhibit dual-emission characteristics and a ratiometric luminescence response that is sensitive to temperature and solvent polarity. Steady-state and time-resolved measurements on 1a, 1b, and 2 indicate that the MOF structures stabilize ground-state CT interactions that are distinct from the weakly-bound exciplexes formed in comparable mixtures of purely organic components. The spectra for 1a and 1b also indicate different temperature dependencies that correspond to thermally-activated complex formation (ΔHf = +1.1 ± 0.2 kcal mol−1) in 1a and static quenching effects (ΔHf = −2.2 ± 0.3 kcal mol−1) in 1b. The addition of ethanol, isopropanol, toluene, or chloroform to suspensions of 1b indicate destabilization of the CT state with increasing solvent polarity, which suggests the generalized application of this or related materials in sensor applications.

Graphical abstract: Charge-transfer guest interactions in luminescent MOFs: implications for solid-state temperature and environmental sensing

Back to tab navigation
Please wait while Download options loads

Supplementary files

Publication details

The article was received on 21 Mar 2012, accepted on 28 May 2012 and first published on 01 Jun 2012


Article type: Paper
DOI: 10.1039/C2DT30649B
Citation: Dalton Trans., 2012,41, 8869-8877
  •   Request permissions

    Charge-transfer guest interactions in luminescent MOFs: implications for solid-state temperature and environmental sensing

    P. L. Feng, K. Leong and M. D. Allendorf, Dalton Trans., 2012, 41, 8869
    DOI: 10.1039/C2DT30649B

Search articles by author