Organometallic complexes immobilized on surfaces combine the high selectivity of homogeneous catalysts with the ease of separation of catalyst from products attainable with heterogeneous catalysts. Here we report a novel approach for the highly controlled preparation of surface organometallic catalysts by gas-phase ligand stripping combined with reactive landing of mass-selected ions onto self-assembled monolayer surfaces. Collision-induced dissociation is used to generate highly reactive undercoordinated metal complexes in the gas-phase for subsequent surface immobilization. Complexes with an open coordination shell around the metal center are demonstrated to show enhanced activity towards reactive landing in comparison to fully ligated species. In situ TOF-SIMS analysis indicates that the immobilized complexes exhibit behavior consistent with catalytic activity when exposed to gaseous reagents.