Table 6. DFT Calculated Aromaticity Indices and Orbital Properties for HMBs 1, 5 and Azulene.

entry	structure	CR	HOMA	NICS(1)ZZ	pEDA	HOMOa	LUMOa	FMO gap	VIPa	VEAa
1	1twist	N	0.70	–7.6	0.907	–6.485	–4.158	2.327
2	1planar		0.70	–7.2	0.905	–6.484	–4.164	2.320	8.51	2.17
3	5a	C–H	0.68	–10.4	0.808	–5.351	–2.813	2.539	7.30	0.94
4	5b	C–CN	0.52	–7.5	0.857	–6.591	–4.480	2.040	8.27	2.77
5	5c	C–Cl	0.59	–8.4	1.025	–5.564	–3.135	2.430	7.36	1.39
6	5d	C–Me	0.64	–9.3	0.811	–4.996	–2.471	2.520	6.82	0.71
7	5e	C–F	0.65	–9.9	0.973	–5.596	–3.009	2.590	7.55	1.09
8	5f	C–OH	0.79	–10.6	0.997	–5.014	–2.317	2.700	6.93	0.45
9	5g	C–NH2	0.73	–10.6	1.038	–4.462	–1.898	2.560	6.29	0.13
10	5hchair	C–NO				–6.649	–5.201	1.450
11	5hplanar		0.19	–4.0	0.630	–6.760	–5.330	1.430	8.76	3.59
12	5i	C–CF3	0.51	–6.4	0.833	–6.263	–4.025	2.240	8.10	2.25
13	5j	C–NO2	0.57	–7.8	0.880	–6.590	–4.454	2.140	8.37	2.75
14	5kboat	C–SO2F				–6.890	–4.781	2.110
15	5kplanar		0.45	–6.0	0.925	–6.809	–4.634	2.170	8.54	2.97
16	azulene					–5.558	–2.269	3.288

^aElectron volts (eV).