An efficient heterogeneous Cu-grafted mesoporous organosilicas nanocatalyst for two and three component C-S coupling reactions.

An efficient heterogeneous Cu-grafted mesoporous organosilicas nanocatalyst for two and three component C-S coupling reactions.

Journal of nanoscience and nanotechnology (2013-08-02)

John Mondal, Noor Salam, Asim Bhaumik

ABSTRACT

Furfural-imine functionalized mesoporous organosilica material has been synthesized by post-synthesis surface functionalization of 2D-hexagnoal mesoporous SBA-15 with organosilane precursor 3-aminopropyltriethoxy-silane (APTES) followed by Schiff-base condensation with furfural. On the other hand, furfural-imine functionalized MCM-41 has been synthesized by Schiff-base condensation of furfural and 3-aminopropyltriethoxy-silane (APTES) followed by its hydrothermal co-condensation with tetraethylorthosilicate (TEOS) in the presence of a cationic surfactant CTAB. Subsequent reaction of the imine-functionalized mesoporous organosilicas with Cu(OAc)2 in absolute ethanol produced Cu(II)-grafted mesoporous nanocatalysts 1 and 2, respectively. Powder XRD, HR TEM, FE SEM, N2 sorption and EPR experimental tolls are employed to characterize these Cu-grafted furfural-imine functionalized nanocatalysts. Cu-grafted MCM-41 (1) showed very good catalytic efficiency for the coupling of aryl bromides and thiophenol under aerobic conditions to produce different thioethers. On the other hand, Cu-anchored mesoporous SBA-15 nanocatalyst (2) exhibited high catalytic activity for one-pot three component coupling of different aryl halides with thiourea and benzyl bromide in aqueous medium to produce different aryl alkyl thioethers in very good yields. Both Cu-grafted mesoporous nanocatalysts can be efficiently reused for several reaction cycles.

MATERIALS

Product Number

Brand

Product Description

718483

Sigma-Aldrich

Silica, nanopowder, 99.8% trace metals basis

BCR058

Continuous cast copper (O), BCR^®, certified reference material, rod

420786

Sigma-Aldrich

LUDOX^® TM-40 colloidal silica, 40 wt. % suspension in H₂O

420794

Sigma-Aldrich

LUDOX^® SM colloidal silica, 30 wt. % suspension in H₂O

420824

Sigma-Aldrich

LUDOX^® HS-30 colloidal silica, 30 wt. % suspension in H₂O

420808

Sigma-Aldrich

LUDOX^® LS colloidal silica, 30 wt. % suspension in H₂O

12816

Sigma-Aldrich

Copper, foil, ≥99.8% (complexometric)

326488

Sigma-Aldrich

Copper, beads, 2-8 mm, ≥99.99% trace metals basis

701491

Sigma-Aldrich

Silicon dioxide, alumina doped, nanoparticles, dispersion, <50 nm particle size, 20 wt. % in H₂O, ≥99.9% trace metals basis

420883

Sigma-Aldrich

LUDOX^® CL colloidal silica, 30 wt. % suspension in H₂O

349208

Sigma-Aldrich

Copper, foil, thickness 0.025 mm, 99.98% trace metals basis

349216

Sigma-Aldrich

Copper, wire, diam. 1.0 mm, ≥99.9%

349151

Sigma-Aldrich

Copper, foil, thickness 0.5 mm, 99.98% trace metals basis

349224

Sigma-Aldrich

Copper, wire, diam. 2.0 mm, 99.999% trace metals basis

326410

Sigma-Aldrich

Copper, wire, diam. 0.64 mm, 99.995% trace metals basis

254177

Sigma-Aldrich

Copper, beads, 2-8 mm, 99.9995% trace metals basis

421553

Sigma-Aldrich

Silica

266744

Sigma-Aldrich

Copper, foil, thickness 1.0 mm, 99.999% trace metals basis

326429

Sigma-Aldrich

Copper, wire, diam. 0.25 mm, 99.999% trace metals basis

207780

Sigma-Aldrich

Copper, powder, <75 μm, 99%

560979

Sigma-Aldrich

Silica, mesostructured, MSU-F (cellular foam)

61139

Sigma-Aldrich

Copper, turnings, purum p.a., ≥99.0%

643645

Sigma-Aldrich

Silica, mesostructured, MCM-41 type (hexagonal)

637246

Sigma-Aldrich

Silicon dioxide, nanopowder (spherical, porous), 5-20 nm particle size (TEM), 99.5% trace metals basis

637238

Sigma-Aldrich

Silicon dioxide, nanopowder, 10-20 nm particle size (BET), 99.5% trace metals basis

748161

Sigma-Aldrich

Silica, nanoparticles, mesoporous, 200 nm particle size, pore size 4 nm

774103

Sigma-Aldrich

Copper, nanopowder, 60-80 nm particle size (SAXS), ≥99.5% trace metals basis

774111

Sigma-Aldrich

Copper, nanopowder, 40-60 nm particle size (SAXS), ≥99.5% trace metals basis

223409

Sigma-Aldrich

Copper, shot, −3-+14 mesh, 99%

203122

Sigma-Aldrich

Copper, powder, 99.999% trace metals basis