Probing Zeolite Crystal Architecture and Structural Imperfections using Differently Sized Fluorescent Organic Probe Molecules.
Frank C HendriksJoel E SchmidtJeroen A RomboutsKoop LammertsmaPieter C A BruijnincxBert M WeckhuysenPublished in: Chemistry (Weinheim an der Bergstrasse, Germany) (2017)
A micro-spectroscopic method has been developed to probe the accessibility of zeolite crystals using a series of fluorescent 4-(4-diethylaminostyryl)-1-methylpyridinium iodide (DAMPI) probes of increasing molecular size. Staining large zeolite crystals with MFI (ZSM-5) topology and subsequent mapping of the resulting fluorescence using confocal fluorescence microscopy reveal differences in structural integrity: the 90° intergrowth sections of MFI crystals are prone to develop structural imperfections, which act as entrance routes for the probes into the zeolite crystal. Polarization-dependent measurements provide evidence for the probe molecule's alignment within the MFI zeolite pore system. The developed method was extended to BEA (Beta) crystals, showing that the previously observed hourglass pattern is a general feature of BEA crystals with this morphology. Furthermore, the probes can accurately identify at which crystal faces of BEA straight or sinusoidal pores open to the surface. The results show this method can spatially resolve the architecture-dependent internal pore structure of microporous materials, which is difficult to assess using other characterization techniques such as X-ray diffraction.
Keyphrases
- living cells
- single molecule
- room temperature
- fluorescent probe
- quantum dots
- high resolution
- small molecule
- magnetic resonance imaging
- genome wide
- machine learning
- fluorescence imaging
- computed tomography
- deep learning
- optical coherence tomography
- gestational age
- magnetic resonance
- photodynamic therapy
- mass spectrometry
- molecular dynamics simulations
- preterm birth
- flow cytometry