High-spin surface Fe = O synthesis with molecular oxygen and pyrite for selective methane oxidation.

Nature-inspired high-spin Fe = O generation enables efficient ambient methane oxidation. By engineering sulfur-bridged dual ≡Fe…Fe≡ sites on pyrite (FeS) mimicking soluble methane monooxygenase, we achieve O-driven formation of high-spin (S = 2) surface Fe = O species at room temperature and pressure. Strategic removal of bridging S atoms creates active sites that facilitate O activation via transient ≡Fe-O-O-Fe≡ intermediates, promoting homolytic O - O bond cleavage. The resulting Fe = O exhibits an asymmetrically distorted coordination environment that reduces the crystal field splitting and favors the occupation of higher energy d-orbitals with unpaired electrons. Impressively, this configuration can efficiently convert CH to CHOH through an oxygen transfer reaction with a synthetic efficiency of TOF = 27.4 h and selectivity of 87.0%, outperforming most ambient O-driven benchmarks under comparable conditions and even surpassing many HO-mediated systems. This study offers a facile method to synthesize high-spin surface Fe = O and highlights the importance of metal spin state tailoring on non-enzymatic methane activation.