Straightforward Immobilization of Phosphonic Acids and Phosphoric Acid Esters on Mesoporous Silica and Their Application in an Asymmetric Aldol Reaction

Christian Weinberger; Tatjana Heckel; Patrick Schnippering; Markus Schmitz; Anpeng Guo; Waldemar Keil; Heinrich C Marsmann; Claudia Schmidt; Michael Tiemann; René Wilhelm

doi:10.3390/nano9020249

Straightforward Immobilization of Phosphonic Acids and Phosphoric Acid Esters on Mesoporous Silica and Their Application in an Asymmetric Aldol Reaction

Nanomaterials (Basel). 2019 Feb 12;9(2):249. doi: 10.3390/nano9020249.

Authors

Affiliations

¹ Department of Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany. christian.weinberger@upb.de.
² Department of Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany. tatjana.heckel@fh-bielefeld.de.
³ Department of Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany. schnippe@mail.uni-paderborn.de.
⁴ Department of Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany. markusschmitz88@googlemail.com.
⁵ Department of Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany. anpeng1108@gmail.com.
⁶ Department of Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany. keilw@mail.uni-paderborn.de.
⁷ Department of Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany. heinrich.marsmann@uni-paderborn.de.
⁸ Department of Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany. claudia.schmidt@uni-paderborn.de.
⁹ Department of Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany. michael.tiemann@uni-paderborn.de.
¹⁰ Department of Chemistry, Paderborn University, Warburger Str. 100, D-33098 Paderborn, Germany. rene.wilhelm@uni-paderborn.de.

Abstract

The combined benefits of moisture-stable phosphonic acids and mesoporous silica materials (SBA-15 and MCM-41) as large-surface-area solid supports offer new opportunities for several applications, such as catalysis or drug delivery. We present a comprehensive study of a straightforward synthesis method via direct immobilization of several phosphonic acids and phosphoric acid esters on various mesoporous silicas in a Dean⁻Stark apparatus with toluene as the solvent. Due to the utilization of azeotropic distillation, there was no need to dry phosphonic acids, phosphoric acid esters, solvents, or silicas prior to synthesis. In addition to modeling phosphonic acids, immobilization of the important biomolecule adenosine monophosphate (AMP) on the porous supports was also investigated. Due to the high surface area of the mesoporous silicas, a possible catalytic application based on immobilization of an organocatalyst for an asymmetric aldol reaction is discussed.

Keywords: host–guest materials; magic-angle spinning NMR (MAS-NMR); mesoporous silica; organocatalysis.