Synthesis, characterisation, and fluorescence spectroscopic mobility studies of fluorene labeled inorganic–organic hybrid polymers

Hans-Joachim Egelhaaf; Elisabeth Holder; Petr Herman; Hermann A. Mayer; Dieter Oelkrug; Ekkehard Lindner

doi:10.1039/B102088I

Hans-Joachim Egelhaaf,^a Elisabeth Holder,^b Petr Herman,^c Hermann A. Mayer,^b Dieter Oelkrug^a and Ekkehard Lindner*^b

Author affiliations

* Corresponding authors

^a Institut für Physikalische und Theoretische Chemie der Universität Tübingen, Auf der Morgenstelle 8, Tübingen, Germany

^b Institut für Anorganische Chemie der Universität Tübingen, Auf der Morgenstelle 18, Tübingen, Germany
E-mail: ekkehard.lindner@uni-tuebingen.de

^c Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, 725 West Lombard St., Baltimore, Md., U.S.A.

Abstract

In the attempt to find catalyst supports with improved accessibilities for tethered transition metal complexes, a series of inorganic–organic hybrid polymers was synthesised by sol–gel processing of three different silyl-functionalised alkyl derivatives. The resulting materials were characterised by solid-state NMR spectroscopy, BET measurements and elemental analysis. Molecular mobilities in the solvent-swollen polymers were determined by fluorescence spectroscopy. As fluorescent probe, fluorene was covalently attached to the polymer matrix by a T-silyl-functionalised alkyl spacer. The rotational mobilities of the probe were determined by steady-state and time-resolved fluorescence depolarisation experiments. Translational mobilities of molecular species dissolved in the liquid phase were investigated by the kinetics of luminescence quenching after pulsed laser excitation. Both rotational and translational mobilities in hybrid materials are significantly higher than in conventional Q-type polysiloxanes. However, the mobilities are still about one to two orders of magnitude lower than in homogeneous solutions, and thus contribute to the reduced accessibilities of matrix bound transition metal catalysts. The highest mobilities were observed in dichloromethane and organic ethers, which have the strongest swelling capabilities for the hybrid polymers. Compared to D-silyl polymers, mobilities in T-silyl based materials are significantly higher.

Article information

https://doi.org/10.1039/B102088I

Article type

Paper

Submitted

06 Mar 2001

Accepted

26 Jun 2001

First published

13 Aug 2001

Download Citation

J. Mater. Chem., 2001,11, 2445-2452

Permissions

Request permissions