DFT calculation details. All calculations were done with the VASP code. 56-58 Geometry optimizations were done using the PBE38 functional with D3BJ dispersion corrections, with a planewave kinetic energy cutoff of 420 eV, and a 6×6×1 gamma-centered grid of reciprocal space points. The polymer was positioned in the xy plane, and 10 Å of vacuum were added in z (13 Å when axial ligands were present). Total energies were converged to 0.1 meV. Finally, a single-point calculation was done at an 8×8×1 k grid to evaluate the electronic structure and total energy more accurately; the output of this calculation was used in subsequent analysis.