Theoretical Investigation on Local Structure Distortion of V ⁴⁺ ‐Doped DUT‐5(Al) via EPR Parameter Calculation

To clarify the correlation between the V 4+ doping and the structure of DUT‐5(Al), this study establishes a theoretical calculation model for the electron paramagnetic resonance (EPR) parameters of V 4+ with a 3d 1 electron configuration in orthorhombically compressed octahedrons. After verifying the rationality of the model by fitting with experimental data, the local structural distortion of [VO 6 ] clusters, the regulation mechanism of electronic states, and the essence of EPR components ( lp , np , BL , and Blp ) were systematically analyzed. The findings reveal that, due to the Jahn–Teller distortion, the [VO 6 ] units adopt an orthorhombically distorted octahedral structure, quantified by an axial compression parameter ρ ranging from 5.6% to 6.4%, and in‐plane bond‐length variation rate τ spanning 6.0% to 6.8%. The theoretical method adopted in this study can clarify the doping mechanism of transition metal ions in metal–organic frameworks (MOFs), provide theoretical support for interpreting the EPR phenomena of V 4+ ‐doped DUT‐5(Al), and offer guidance for the rational design and performance optimization of transition metal‐doped MOF materials.