title: Design of a Heterogeneous Catalyst Based on Cellulose Nanocrystals for Cyclopropanation: Synthesis and Solid-State NMR Characterization.
abstract: Heterogeneous dirhodium(II) catalysts based on environmentally benign and biocompatible cellulose nanocrystals (CNC-Rh2) as support material were obtained by ligand exchange between carboxyl groups on the CNC surface and Rh2(OOCCF3)4, as was confirmed by solid-state (19)F and (13)C NMR spectroscopy. On average, two CF3COO(-) groups are replaced during ligand exchange, which is consistent with quantitative analysis by a combination of (19)F NMR spectroscopy and thermogravimetry. CNC-Rh2 catalysts performed well in a model cyclopropanation reaction, in spite of the low dirhodium(II) content on the CNC surface (0.23 mmol g(-1)). The immobilization through covalent bonding combined with the separate locations of binding positions and active sites of CNC-Rh2 guarantees a high stability against leaching and allows the recovery and reuse of the catalyst during the cyclopropanation reaction.
authors.affiliation: Eduard-Zintl-Institute for Inorganic Chemistry and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Strasse 8, 64287 Darmstadt (Germany).
authors.forename: Jiquan
authors.initials: J
authors.lastname: Liu
authors.affiliation: Center of Smart Interfaces, Technische Universität Darmstadt, Alarich-Weiss-Strasse 10, 64287 Darmstadt (Germany).
authors.forename: Andreas
authors.initials: A
authors.lastname: Plog
authors.affiliation: Eduard-Zintl-Institute for Inorganic Chemistry and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Strasse 8, 64287 Darmstadt (Germany).
authors.forename: Pedro
authors.initials: P
authors.lastname: Groszewicz
authors.affiliation: Eduard-Zintl-Institute for Inorganic Chemistry and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Strasse 8, 64287 Darmstadt (Germany).
authors.forename: Li
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Eduard-Zintl-Institute for Inorganic Chemistry and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Strasse 8, 64287 Darmstadt (Germany).
authors.forename: Yeping
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Eduard-Zintl-Institute for Inorganic Chemistry and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Strasse 8, 64287 Darmstadt (Germany).
authors.forename: Hergen
authors.initials: H
authors.lastname: Breitzke
authors.affiliation: College of Agriculture, Engineering and Science, School of Engineering, University of KwaZulu-Natal, Howard College Campus, Durban (South Africa).
authors.forename: Annegret
authors.initials: A
authors.lastname: Stark
authors.affiliation: Eduard-Zintl-Institute for Inorganic Chemistry and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Strasse 12, 64287 Darmstadt (Germany).
authors.forename: Rudolf
authors.initials: R
authors.lastname: Hoffmann
authors.affiliation: Eduard-Zintl-Institute for Inorganic Chemistry and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Strasse 8, 64287 Darmstadt (Germany). gutmann@chemie.tu-darmstadt.de.
authors.forename: Torsten
authors.initials: T
authors.lastname: Gutmann
authors.affiliation: Ernst-Berl-Institute for Chemical Engineering and Macromolecular Science, Technische Universität Darmstadt, Alarich-Weiss-Strasse 8, 64287 Darmstadt (Germany). kzhang1@uni-goettingen.de.|Wood Technology and Wood Chemistry, Georg-August-Universität Göttingen, Büsgenweg 4, 37077 Göttingen (Germany). kzhang1@uni-goettingen.de.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Eduard-Zintl-Institute for Inorganic Chemistry and Physical Chemistry, Technische Universität Darmstadt, Alarich-Weiss-Strasse 8, 64287 Darmstadt (Germany). gerd.buntkowsky@chemie.tu-darmstadt.de.
authors.forename: Gerd
authors.initials: G
authors.lastname: Buntkowsky
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D003521:Cyclopropanes / Q000138:chemical synthesis* / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D053758:Nanoparticles / Q000737:chemistry*; D060327:Solid-Phase Synthesis Techniques
chemical_list: D003521:Cyclopropanes; D002482:Cellulose; C030797:cyclopropane
keywords: cellulose; cyclization; nanoparticles; rhodium; supported catalysts