Electronic properties of the derivatives in gas phase and solution.

Molecule	HOMO–LUMO (eV)	Hardness (eV)	Softness (eV)	Mulliken electronegativity (eV)	Electrophilicity (eV)
Gas phase
1-F	3.88	1.94	0.51	−5.02	50.40
1-Cl	3.91	1.95	0.51	−4.98	49.70
1-Br	3.83	1.91	0.52	−4.98	49.70
2-F	4.62	2.31	0.43	−5.02	50.40
2-Cl	4.64	2.32	0.43	−5.00	50.00
2-Br	4.58	2.29	0.44	−4.96	49.20
Solution
1-F	3.95	1.97	0.51	−4.87	47.53
1-Cl	3.98	1.99	0.50	−4.84	46.85
1-Br	3.89	1.94	0.51	−4.83	46.75
2-F	4.70	2.35	0.42	−4.96	49.2
2-Cl	4.67	2.33	0.43	−4.91	48.31
2-Br	4.59	2.29	0.44	−4.87	47.53