Ammonium tagged Hoveyda-Grubbs catalysts immobilized on magnetically separable core-shell silica supports for ring-closing metathesis reactions


ÖZTÜRK B. Ö.

MICROPOROUS AND MESOPOROUS MATERIALS, cilt.267, ss.249-256, 2018 (SCI İndekslerine Giren Dergi) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 267
  • Basım Tarihi: 2018
  • Doi Numarası: 10.1016/j.micromeso.2018.04.002
  • Dergi Adı: MICROPOROUS AND MESOPOROUS MATERIALS
  • Sayfa Sayıları: ss.249-256

Özet

Ammonium tagged Hoveyda-Grubbs (Ru-1) catalyst was immobilized on core-shell structured silica gel bearing a magnetic nano-sized alpha-Fe2O3 core via non-covalent interactions. Core-shell silica gel materials were synthesized using a two-step coating procedure of alpha-Fe2O3 in the presence of cationic (dodecyl trimethyl ammonium chloride, DTMAC) and non-ionic (Synperonic F108) surfactants and tetraethoxysilane (TEOS) as the silica source. Double SiO2 coated SiO2(2)@alpha-Fe203 supports with a high surface area of 646 m(2)/g and pore size/volumes of 2.88 nm/0.393 cm(3) were obtained after removal of template surfactants from silica gel by extraction. Supported catalyst, Ru-1@SiO2(2)@alpha-Fe2O3, was found to be very active in ring-closing metathesis (RCM) reactions of diethyl diallyl malonate (DEDAM) and various dienes. The catalyst can be easily separated from the reaction mixture with the aid of a magnet and was reusable up to eight times with low Ru leaching levels.