Table 3. Frontier Orbital Energies of the Seven Synthesized Compounds and Leflunomide.

compound	HOMO (ev)	LUMO (ev)	energy gap (ΔE)
3	–0.223650	–0.046990	–0.17666
4a	–0.209278	–0.043641	–0.16564
4b	–0.198182	–0.039350	–0.15883
5a	–0.177838	–0.035467	–0.14237
5b	–0.184413	–0.032434	–0.15198
5c	–0.210149	–0.070595	–0.13955
5d	–0.205535	–0.081115	–0.12442
Leflunomide	–0.348842	–0.178321	–0.17052