Computational Design of a Pincer Phosphinito Vanadium ((OPO)V) Propane Monoxygenation Homogeneous Catalyst Based on the Reduction-Coupled Oxo Activation (ROA) Mechanism

We propose the vanadium bis(2-phenoxyl)phosphinite pincer complex, denoted (OPO)V, as a low-temperature water-soluble catalyst for monoxygenation of propane to isopropanol with functionalization and catalyst regeneration using molecular oxygen. We use density functional theory (DFT) study to predict that the barrier for (OPO)V to activate the secondary hydrogen of propane is ΔG^‡ = 25.2 kcal/mol at 298 K, leading to isopropanol via the new reduction-coupled oxo activation (ROA) mechanism. We then show that reoxidation by dioxygen to complete the cycle is also favorable with ΔG^‡ = 6.2 kcal/mol at 298 K. We conclude that (OPO)V represents a promising homogeneous catalyst for the monoxygenation of propane and other alkanes (including ethane), warranting experimental validation.