Table 1. NBO Analysis of CPFH, CCPH, and BCPH^a.

comp	donor (i)	types	acceptor (j)	types	E(2)	E(j) – E(i) (au)	F(i,j) (au)
CPFH	C5-N6	σ	C1-Cl10	σ*	5.89	1.13	0.073
	C25-C28	π	C22-C23	π*	34.07	0.36	0.101
	C1-N6	π	C4-C5	π*	36.31	0.42	0.114
	C4-C5	π	C2-C3	π*	38.71	0.38	0.109
	C2-C3	π	C1-N6	π*	46.48	0.33	0.114
	O16	LP(2)	C15-N17	σ*	31.64	0.83	0.147
	N17	LP(1)	N19-C20	π*	32.38	0.39	0.105
	O11	LP(2)	C4-C5	π*	38.99	0.44	0.124
	N17	LP(1)	C15-O16	π*	73.44	0.39	0.153
CCPH	C 22-C24	σ	C23-Cl32	σ*	6.51	0.96	0.071
	C24-C26	π	C25-C28	π*	31.93	0.37	0.097
	C1-N6	π	C4-C5	π*	36.35	0.42	0.114
	C4-C5	π	C2-C3	π*	38.64	0.38	0.109
	C2-C3	π	C1-N6	π*	46.45	0.33	0.114
	O16	LP(2)	C15-N17	σ*	31.77	0.83	0.147
	N17	LP(1)	N19-C20	π*	32.9	0.39	0.105
	O11	LP(2)	C4-C5	π*	38.86	0.44	0.124
	N17	LP(1)	C15-O16	π*	72.72	0.39	0.153
BCPH	C22-C24	σ	C22-C23	σ*	6.73	1.39	0.086
	C24-C26	π	C25-C28	π*	31.65	0.37	0.097
	C1-N6	π	C4-C5	π*	36.33	0.42	0.114
	C4-C5	π	C2-C3	π*	38.64	0.38	0.109
	C2-C3	π	C1-N6	π*	46.44	0.33	0.114
	O16	LP(2)	C15-N17	σ*	31.76	0.83	0.147
	N17	LP(1)	N19-C20	π*	32.77	0.39	0.105
	O11	LP(2)	C4-C5	π*	38.89	0.44	0.124
	N17	LP(1)	C15-O16	π*	72.82	0.39	0.153

^aComp = compounds, LP = lone pair, (j) acceptor, (i) donor, E⁽²⁾ means energy of hyper conjugative interaction (stabilization energy), F(i, j) is the Fock matrix element between i and j NBO orbitals, and E(j) – E(i) is the energy difference between donor and acceptor i and j NBO orbitals.