The density functional
theory (DFT) method using the
functional
hybrid (B3LYP) and 6-311G(d,p) basis set was utilized for the geometry
optimization with dispersion correction, procedure (GO + DC), for
the E and Z chalcone isomers ̵1-(4-aminophenyl)-
3-(i,j-dichlorophenyl)prop-2-en-1-one,
where (i) and (j) represent the
positions of the two chlorine atoms [(2,3), (2,4),(2,5),(2,6),(3,4),
and (3,5)] abbreviated (i,j)-chalcone,
and 4-(x,y-dichloro-8aH-chromen-2-yl)aniline, where (x = 5,6 and y = 6,7,8,8a) abbreviated (x,y)-chromen isomers. The calculations revealed that E chalcones are the most stable and the 4-(x,y-dichloro-8aH-chromen-2-yl) aniline isomers
are the least stable. The (3,5) chalcones were the most stable in
both E and Z chalcone series. However,
the 4-(5,8a-dichloro-8aH-chromen-2-yl) aniline is
the most stable in the series. The isomer stability order is the same
as in Part 1, in which the geometry optimization calculation was followed
by the dispersion correction single point energy calculation (GO/SPDC)
procedure. The procedures (GO + DC) and (GO/SPDC) were used to calculate
energies of the highest occupied molecular orbital (HOMO) and lowest-unoccupied
molecular orbital (LUMO) and related properties. The order of the
HOMO–LUMO energy gap (ΔE
gap) was chromens