Reaction of 1'-(diphenylphosphino)ferrocenecarboxylic acid (Hdpf) with mesoporous molecular sieve MCM-41 gives immobilized carboxyphosphine (3). which was further reacted with [{Ru(eta(6)-p-cymene)Cl(mu-Cl)}(2)] (1) to afford Ru/carboxyphosphine-modified molecular sieve 4. A simple reaction between MCM-41 and 1 afforded Ru-only modified molecular sieve 5. Materials 4 and 5 were tested as catalysts for the reaction of propargyl alcohol with benzoic acid to give 2-oxopropyl benzoate (6). The reactions catalyzed with immobilized catalysts are slower and give lower yields of the ester as compared to the homogeneous precatalyst [Ru(eta(6)-p-cymene)(Hdpf-kappaP)Cl-2] (2), which was prepared from Hdpf and the dimer 1. Formation of ester 6 catalyzed with 4 and 5 competes with a parallel. propargyl alcohol consuming process, which occurs also with MCM-41 itself in the absence of benzoic acid and ruthenium compounds. The solid-state structure of 2.CH2Cl2 has been determined by single-crystal X-ray diffraction. (C) 2004 Elsevier B.V. All rights reserved.