Encapsulation of copper(I)-Schiff base complex in NaY nanoporosity: An efficient and reusable catalyst in the synthesis of propargylamines via A3-coupling (aldehyde-amine-alkyne) reactions

Nanodimensional microreactor containing bis[2-(phenylthio)benzylidene]-1,2-ethylenediamine copper(I) complexes, [Cu(N2S2)]X-Y (X = CN, Cl, Br, I) was successfully prepared. This nano composite was used as a catalyst in one-pot multicomponent coupling reaction of aldehydes, amines and alkynes toward synthesis of propargylamines. The copper(I) complex with N2S2 donor Schiff base ligand was readily trapped in the nanocavity of zeolite-Y through a template synthetic (TS) method. Two consecutive processes in the liquid phase were carried out: (i) preparation of a solution of [Cu(MeCN)(4)]X coordinated with 2-(phenylthio)-benzaldehyde in the presence of zeolite-Y. This process caused the inclusion of [Cu(MeCN)(2)(S2O2)]X complex into the nanopores of zeolite Y via pre-adsorption method; (ii) template synthesis of the [Cu(MeCN)(2)(N2S2)]X-Y, through Schiff condensation between [Cu(MeCN)(2)(S2O2)]X and 1,2-ethylenediamine moiety into the nanopores of NaY. The resulting catalysts were fully characterized by spectroscopic techniques such as AAS, FT-IR, BET isotherm, XRD, UV-Vis and TGA. The results confirmed encapsulation of Y-zeolite with copper(I) complex of N2S2 donor ligand. The catalytic activity of this nanocomposite material was investigated for preparation of propargylamines via three-component reaction of aldehydes, amines and alkynes. Also, the effective factors on this condensation reaction were discussed, such as reaction temperature, solvent, catalyst loading, leaching and reusability of the catalyst. (C) 2013 Elsevier B.V. All rights reserved.