. Author manuscript; available in PMC: 2023 Dec 1.

Published in final edited form as: Catal Sci Technol. 2022 Sep 22;12(21):6581–6589. doi: 10.1039/d2cy01136k

Table 5.

HOMO and LUMO Energy Levels (eV) of Imidazo[1,5-a]pyridin-3-ylidenes Calculated at the B3LYP 6–311++g(d,p) Level^a

entry	NHC	HOMO [eV]	LUMO [eV]
1	1a	−5.86^b	−1.24
2	1b	−5.91^b	−1.29
3	1c	−5.87^b	−1.25
4	1d	−5.91^b	−1.30
5	IMes	−5.90	−0.33^c
6	IPr	−6.01	−0.48^c

See SI for details.

HOMO-1, in-plane σ-orbital. HOMO: π-donor orbital, 1a: -5.43 eV, 1b: -5.49 eV, 1c: -5.44 eV; 1d: -5.50 eV.

LUMO+2, LUMO+1 due to required symmetry.