Get access

Salen-Based Coordination Polymers of Manganese and the Rare-Earth Elements: Synthesis and Catalytic Aerobic Epoxidation of Olefins

Authors

  • Dr. Asamanjoy Bhunia,

    1. Institut für Anorganische Chemie, Karlsruhe Institute of Technology (KIT), Engesserstrasse 15, D-76131 Karlsruhe (Germany), Fax: (+49) 721-608-44854
    Search for more papers by this author
  • Meike A. Gotthardt,

    1. Institute of Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstrasse 18, 76131 Karlsruhe (Germany), Fax: (+49) 721-608-44820
    Search for more papers by this author
  • Munendra Yadav,

    1. Institut für Anorganische Chemie, Karlsruhe Institute of Technology (KIT), Engesserstrasse 15, D-76131 Karlsruhe (Germany), Fax: (+49) 721-608-44854
    Search for more papers by this author
  • Dr. Michael T. Gamer,

    1. Institut für Anorganische Chemie, Karlsruhe Institute of Technology (KIT), Engesserstrasse 15, D-76131 Karlsruhe (Germany), Fax: (+49) 721-608-44854
    Search for more papers by this author
  • Dr. Andreas Eichhöfer,

    1. Institut für Nanotechnologie, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76021 Karlsruhe (Germany)
    Search for more papers by this author
  • Dr. Wolfgang Kleist,

    Corresponding author
    1. Institute of Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstrasse 18, 76131 Karlsruhe (Germany), Fax: (+49) 721-608-44820
    2. Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)
    • Institute of Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstrasse 18, 76131 Karlsruhe (Germany), Fax: (+49) 721-608-44820
    Search for more papers by this author
  • Prof. Dr. Peter W. Roesky

    Corresponding author
    1. Institut für Anorganische Chemie, Karlsruhe Institute of Technology (KIT), Engesserstrasse 15, D-76131 Karlsruhe (Germany), Fax: (+49) 721-608-44854
    • Institut für Anorganische Chemie, Karlsruhe Institute of Technology (KIT), Engesserstrasse 15, D-76131 Karlsruhe (Germany), Fax: (+49) 721-608-44854
    Search for more papers by this author

Abstract

Treatment of N,N′-bis(4carboxysalicylidene)ethylenediamine (H4L), with MnCl2(H2O)4, and Ln(NO3)3(H2O)m (Ln=Nd, Eu, Gd, Dy, Tb), in the presence of N,N-dimethylformamide (DMF)/pyridine at elevated temperature resulted (after work up) in the formation of 1D coordination polymers {[Ln2(MnLCl)2(NO3)2(dmf)5]4 DMF}n (15). In these coordination polymers the rare earth ions are connected through carboxylate groups from Mn–salen units in a 1D chain structure. Thus, the Mn–salen complex acts as a “metalloligand” with open coordination sites. All compounds were used as catalysts in the liquid-phase epoxidation of trans-stilbene with molecular oxygen, which resulted in the formation of stilbene oxide. Since the choice of the lanthanide had virtually no influence on the performance of the catalyst, only the manganese–gadolinium was studied in detail. The influence of solvent, catalyst concentration, reaction temperature, oxidant, and oxidant flow rate on conversion, yield, and selectivity was analyzed. A conversion of up to 70 %, the formation of 61 % stilbene oxide (88 % selectivity), and a TON of 84 were observed after 24 h. A hot filtration test confirmed that the reaction is mainly catalyzed through a heterogeneous pathway, although a minor contribution of homogeneous species could not be completely excluded. The catalyst could be reused without significant loss of activity.

Get access to the full text of this article

Ancillary