High-valent dioxo-Mo species have demonstrated the ability to catalyze the industrially interesting alkene-to-epoxide transformation via Oxygen Atom Transfer (OAT) reactions. The effect of electron donor ligands of dioxo-molybdenum complexes [MoO2Ln] covalently supported on TiO2 nanotubes (MoO2Ln/TiO2-NT) on OAT to α-pinene, β-pinene, (R)-limonene and camphene has been studied using UV-vis radiation and molecular oxygen. Molybdenum complexes with electron donor ligands such as bipyridine, bispyrazole and terpyridine showed high conversion and selectivity towards epoxide formation, suggesting that electron donation improves the efficiency of photostimulated OAT. The photonic efficiency (ξ) shows a linear correlation between the ligand structure and the OAT activity, indicating that the electron donation of the ligands improves the electron mobility towards the Mo=O bond, which correlates with the position of the IR and Raman νsym(O=Mo=O) and vasym(O=Mo=O) vibrations of the complex Mo.