Suzuki cross-coupling reaction over Pd-Schiff-base anchored mesoporous silica catalyst

A new hybrid catalyst has been prepared by tethering a palladium(II) Schiff-base complex via post-synthesis modification of mesoporous silica, MCM-41. The Schiff-base has been derived from o-vanillin and 3-[(2-aminoethylamino)propyl]trimethoxysilane (ATMS) which is chemically anchored on MCM-41 via silicon alkoxide route. The anchored Schiff-base imposed a stable planar coordination sphere on the central palladium ion. The catalyst has been characterized by elemental analysis, small angle Xray diffraction, FT-IR, UV-vis, N-2 sorption study, transmission electron microscopy (TEM) studies and scanning electron microscopy (SEM) studies. X-ray and TEM measurement showed the mesoporosity of the catalyst. The activity of the catalyst has been assessed in the Suzuki C-C cross coupling reaction using various phenyboronic acid in heterogeneous condition. High selectivity for the biaryl products containing both electron-donating and electron-withdrawing substituents, high turnover, mild reaction conditions and possibility of easy recycle makes the catalyst highly desirable to address the industrial needs and environmental concerns. (C) 2014 Elsevier B.V. All rights reserved.