Chemistry Reference
In-Depth Information
Table 11.17
Bonding delocalization energies in kcal/mol (
β =−
55.0819 eV) for the compounds
of Table
11.16
, along the related bondonic radii of action, mass ratio respecting the electronic unit,
and the bondonic gravitational ratio respecting the universal gravitational unit, according with Eqs.
(
11.37a
,
11.37b
,
11.37c
), respectively
Compounds
ς
m
×
10
4
ς
G
×
10
−
52
DE
bond
(
kcal/mol
)
X
B
(Å)
(VI)
−
324.278
11.1668
21.7279
7.59777
(XVIII)
−
323.948
11.1782
21.7058
7.61328
(XIX)
−
298.896
12.115
20.0273
8.94294
(XX)
−
298.434
12.1338
19.9963
8.97069
(XV)
−
283.165
12.7881
18.9732
9.9642
(XIII, XIV)
−
231.168
15.6646
15.4892
14.9509
(XVI)
−
205.566
17.6155
13.7737
18.9069
(XVII)
−
190.859
18.9729
12.7883
21.933
−
(XXI, XXII)
170.148
21.2823
11.4006
27.5974
(XI, XII)
−
143.615
25.2142
9.62278
38.7366
(IX, X)
−
112.863
32.0844
7.56226
62.722
of the amine form in HCl solution, is more aromatic than 4-N, N-dimethylamino
aniline (XXI) as predicted by the values of TOPAZ aromaticity (Tarko
2008
).
The
ε
LUMO
and
ε
HOMO
values indicate that (IX), (X), (XI), (XII) compounds are the
most resistant to oxidation, and the (XVI), (XVII), (XXI) molecules are the most
resistant to reduction. The (XI), (XII) compounds should be stronger oxidizing
agents, and the (XIX), (XXI) compounds should be stronger reducing agent.
For the (IX), (XI), (XIII) compounds that are present in the acidic solution when
sulfanilic acid diazotization occurs, and also the (X), (XII), (XIV) compounds
present in the medium when sulfanilamide is diazotized, the correlations between
λ
calculated
and spectral measurements
λ
exp
are satisfactory (Isac et al.
1981a
).
Regarding the electronic densities (
ρ
r
) calculated by HMO method (Table
11.18
)
correlated with the results obtained by DFT method (Fig.
11.12
), it should be men-
tioned that their relative values are more important than their absolute ones within
this series of similar compounds, or for different atoms of the same substance.
The atoms electronic densities follow the
ρ
0
>ρ
N
>ρ
C
relationship being in
good agreement with the known electronegativity tendency (Putz
2006
,
2007
). The
usage of phenolates and naphtolates, strong nucleophiles, in azo coupling reactions
is based on the fact that the oxygen atom in the
O
−
anion is less electronegative
−
than in the
OH
group due to its negative charge (Simon
1973
, Chap. 2, pp. 35-50).
The calculated values in Table
11.18
place the coupling components upon
reactivity as follow:
−
(
XVII
)
>
(
XVI
)
>
(
XIII
)
(11.67a)
(
XIV
)
>
(
XV
)
(11.67b)
