Table 5. DFT calculated NPA Atomic Charges of HMBs 1 and 5a–k.

structure	N/CR	natural atomic charge
		N1	C2	C3	O
1twist	N	–0.153	–0.228	0.689	–0.625
1planar		–0.152	–0.228	0.689	–0.625
5a	C–H	–0.359	0.002	0.526	–0.674
5b	C–CN	–0.342	0.052	0.583	–0.618
5c	C–Cl	–0.393	0.120	0.528	–0.653
5d	C–Me	–0.370	0.181	0.538	–0.698
5e	C–F	–0.401	0.562	0.489	–0.649
5f	C–OH	–0.386	0.467	0.487	–0.718
5g	C–NH2	–0.392	0.320	0.516	–0.721
5hchair	C–NO	–0.384	0.258	0.599	–0.561
5hplanar		–0.359	0.279	0.581	–0.569
5i	C–CF3	–0.345	0.078	0.556	–0.632
5j	C–NO2	–0.365	0.289	0.547	–0.615
5kboat	C–SO2F	–0.364	–0.063	0.551	–0.603
5kplanar		–0.369	–0.054	0.549	–0.611