Biomedical Engineering Reference
In-Depth Information
reactivity of a site within a molecule toward a nucleophilic or an electro-
philic attack. h at is, if
f
(2)
(
r
)
>
0, then the site is favored for a nucleophilic
attack, whereas if
f
(2)
(
r
)
<
0, then the site may be favored for an electro-
philic attack [58-60].
h e electrophilic f
+
and nucleophilic f
−
condensed Fukui functions and
f
(2)
(
r
) over the atoms of the BFPF Green Fluorescent Protein Chromophore
molecule calculated with the M06, M06L, M06-2X and M06-HF density
functionals and the MIDIY+ basis set are shown in Table 7.15. h e actual
values have been multiplied by 100 for an easier comparison.
h e electron donating (
ω
−
) and electron accepting (
ω
+
) powers have
been dei ned as [61]:
2
(3
IA
IA
)
(7.17)
16(
)
and
2
(3)
16(
I A
IA
(7.18)
)
It follows that a larger
ω
+
value corresponds to a better capability of
accepting charge, whereas a smaller value of
ω
−
value of a system makes
it a better electron donor. In order to compare
ω
+
with -
ω
−
, the following
dei nition of net electrophilicity has been proposed [62]:
(
)
(7.19)
that is, the electron accepting power relative to the electron donating
power. h e electrodonating (
ω
−
) and electroaccepting (
ω
+
) powers and net
electrophilicity Δ
ω
±
of the BFPF Green Fluorescent Protein Chromophore
molecule calculated with the M06, M06L, M06-2X and M06-HF density
functionals and the MIDIY+ basis sets are presented in Table 7.16. h e
upper part of the table shows the results derived assuming the validity of
Koopmans' theorem and the lower part shows the results derived from the
calculated vertical
I
and
A
.
h e results from Table 7.16 clearly indicate that BFPF Green Fluorescent
Protein Chromophore is an electrodonating molecule, with the same
result predicted by all the four density functionals considered in this study.
However, only the results obtained through the calculations with the M06
and M06L density functionals are fairly in agreement between those from
