**4. Conclusions**

PLA based biopolymers have found to be easily functionalized at the carboxylic acid end. The introduced functional group which is located at the chain end of the polymer chain can be exploited to coordinate metal ions, which are successively reduced to form metal nanoparticles, the growth and stabilization of which is controlled by the nature of the introduced functional group. The stereocomplexation of these latter macroligands leads to a polymerbased support which is featured by a much more thermal and hydrolytic stability compared to PLA, due to many hydrogen bond-based interactions between PLA-chains of opposite stereochemistry. In addition, the stereocomplex is insoluble in most organic solvents, so that recycling of the support is easily done upon a simple filtration process. We found that the endfunctionalized of the stereocomplex with 2,2′-bipyridine (**L7/8**) leads to an ideal support for Nps' surface. The stabilization of small Pd-Nps (2.0 nm) generated by the MSV technique, with **L7/8** in the course of the catalytic hydrogenation of α,β-unsaturated carbonyl compounds brings about the notable catalytic activity and chemoselectivity found for the corresponding saturated carbonyl compounds.
