RESEARCH PAPER CHINESE JOURNAL OF CATALYSIS Volume 32, Issue 10, 2011 Online English edition of the Chinese language journal Cite this article as: Chin. J. Catal., 2011, 32: 1597–1603. Received 9 May 2011. Accepted 30 July 2011. *Corresponding author. Tel: +91-1881-242175; Fax: +91-1881-223395; E-mail: rajendra@iitrpr.ac.in The authors thank the Ministry of Human Resource and Development, New Delhi and Director, IIT Ropar for financial assistance. Copyright © 2011, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier BV. All rights reserved. DOI: 10.1016/S1872-2067(10)60266-5 Catalytic Activity of Dual Metal Cyanide Complex in Multi-Component Coupling Reactions Anaswara RAVINDRAN, Rajendra SRIVASTAVA* Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, India Abstract: Several dual metal cyanide catalysts were prepared from potassium ferrocyanide, metal chloride (where metal = Zn 2+ , Mn 2+ , Ni 2+ , Co 2+ , and Fe 2+ ), t-butanol (complexing agent) and PEG-4000 (co-complexing agent). The catalysts were characterized by elemental analysis (CHN and X-ray fluorescence), X-ray diffraction, N 2 adsorption-desorption, scanning electron microscopy, Fourier-transform infrared spectroscopy, and UV-Visible spectroscopy. The dual metal cyanide catalysts were used in several acid catalyzed multi-component coupling reactions for the synthesis of pharmaceutically important organic derivatives. In all these reactions, the Fe-Fe containing dual metal cyanide catalyst was the best catalyst. The catalysts can be recycled without loss in catalytic activity. The advantage of this method is the use of mild, efficient and reusable catalysts for various reactions, which makes them candidates for commercial use. Key words: dual metal cyanide; multi-component coupling reaction; acid catalyst Dual metal cyanide (DMC) catalysts are a class of molecular salts comprising a metal-cyanide crystalline framework with two different metal centers. They have the general formula M 1 u [M 2 (CN) 6 ] v ·yL·zH 2 O (where M 1 = Zn; M 2 = Co, Fe etc.; L = organic complexing agent) [1–4]. DMC catalysts possess zeo- lite-like cage structures [5], and have gained considerable attention for their interesting magnetic, electrochromic, mag- neto-optic, photomagnetic, and nanomagnetic properties [6]. DMC catalysts are insoluble in organic solvents, acids, and even in aqua regia. They are usually prepared by the precipi- tation reaction of an aqueous solution of a water-soluble metal salt (M u 1 X w ), metal cyanide potassium salt (K a [M(CN) n ] v ), and a water-soluble organic complexing agent (L). DMC catalysts were discovered in the 1960’s [7] and were found to have significant catalytic activity in various reactions, in particular in polymerization reactions [8–14]. DMC com- plexes find extensive applications in the ring opening polym- erization of epoxides [1–4]. DMC catalysts can be used to produce polyether, polyester, and poly (ether ester) polyols [8–11]. Environmentally friendly synthesis of biodegradable polycarbonates was realized using DMC catalysts by the co- polymerization of epoxide with CO 2 [12,13]. They have been relatively well investigated with respect to their activity using different preparation routes and operating conditions [12,14]. The recent literature suggest that they can be effectively util- ized in esterification and transesterification reactions for the production of organic carbonates and biodiesel [15,16]. Multi-component reactions are a powerful and useful syn- thetic tool to produce complex molecules from simple pre- cursors by a one-pot procedure [17–19]. In this procedure, there is no need to isolate any intermediate, and there is re- duction in the reaction time and savings in both energy and raw materials. Therefore, the design of novel multi-component reactions has attracted a great deal of attention from research groups working in the field of medicinal chemistry, drug dis- covery, and material science. To utilize DMC in chemical synthesis, Fe-Zn based DMC catalysts have been prepared by varying several synthesis parameters [15,16]. However, the influence on reactivity of changing the metal ions in the DMC has not been explored. The objective of this study is to prepare a variety of DMC catalysts and assess their catalytic activity in chemical synthesis. A variety of Fe-M-containing DMC catalysts (M = Fe, Mn, Co, Ni, and Zn) were prepared (with all other synthesis parameters the same). Their catalytic activities were assessed using multi-component coupling reactions in the synthesis of phar-