Local Donor-State Gating Refines Torsion-Based Prescreening of Wide-Gap Polymer Dielectrics

Backbone torsion is widely used to prescreen wide-gap polymer dielectrics, but it can mis-rank donor-bearing motifs when a lone-pair donor remains aligned. O-, S-, and N-substituted biphenyls separate global torsion θ from donor dihedral ϕ. Fixed-θ scans establish an Acos2 ϕ + B law and scan-calibrated on, mid, and off states. Gate deactivation lowers the HOMO and opens the gap with a smaller LUMO response; M06-2X and def2-QZVP checks preserve this trend. Transferred as a conformer-weighted geometry proxy, donor-state gating raises low-conductivity EF20 from 0.49 to 2.45 and low-conductivity ROC-AUC from 0.464 to 0.801 in PoLyInfo records, without per-candidate quantum calculations. Transfer tests extend the same construction across heteroaryl axes, diaryl O/S/N linkers, and repeat units without a common global torsion axis. Exploratory tests across broader donor-like environments support a mechanism-aware route for future expansion. Donor-state gating therefore provides a scalable, interpretable refinement to torsion-based prescreening.