Table 1. HOMO/LUMO energies, band gap, and molecular dipole moment of hydroxyl-PMI monomer determined from DFT calculations and experimental values for 2.

Species	μ [debye]	E HOMO [eV]		E LUMO [eV]		Bandgap [eV]
		DTF	EXP	DFT	EXP	DFT	EXP
PMI-OH	7.70	–5.52	–5.65	–2.98	–3.70	2.54	1.95
PMI-O–Na+	17.72	–4.78	–4.90	–2.59	–3.33	2.19	1.57