Copper(II) nanoparticles immobilized onto 3‐aminopropyltriethoxysilane (APTES) supported on mesoporous silica KIT‐5 nanocomposite (AK) was prepared. The APTES group on KIT‐5 was manipulated as a suitable coordinating agent for copper(II) and fully characterized using FT‐IR, SEM, EDX, ICP, TGA, XRD and UV–visible methods. Moreover, a quantitative description for metal–ligand interactions in the APTES‐KIT‐5 mesoporous silica‐supported copper(II) acetate complex was assessed via quantum chemistry computations. This novel transition metal supported heterogeneous surface was used as an effective catalyst in low loading for selective oxidation of differently substituted benzylic alcohols in water, using H2O2as oxidant to give the corresponding carbonyl compounds in high to excellent yields. This heterogeneous nanocatalyst can be recovered and reused several times without any significant loss of activity. Copyright © 2016 John Wiley & Sons, Ltd.