New heterogeneous catalysts with Mo(II) intercalated in layered double hydroxides

Abstract The Mo(II) complexes [MoX 2 (CO) 3 (BDC)] (X = I, Br; H 2 BDC = 2,2′-bipyridine-5,5′-dicarboxylic acid) were immobilized by intercalation in two layered double hydroxides (LDH), containing Zn/Al (synthesized) and Mg/Al (commercial), as shown by infrared and 13 C solid state NMR spectroscopies, and X-ray powder diffraction. Their catalytic activity was studied in olefin oxidation, using as oxidant tert -butylhydroperoxide (tbhp), and was compared with the activity of the related [MoX 2 (CO) 3 (bpy)] complexes (bpy = 2,2′-bipyridine). cis -Cyclooctene, styrene, 1-octene, trans -hex-3-en-1-ol, and R -(+)-limonene were the substrates tested. All the catalyst showed in average a high selectivity toward the epoxide of each substrate (above 90%, except for styrene), with variable conversions, but none of the heterogeneous catalysts proved to be more active than the homogeneous ones. The same or higher activity in a second catalytic run, as observed in most reactions, suggests a good recycling capability.