(21) Å (gas phase) and 1.669(3) Å (in crystal), respectively. In addition to the
(CF 3 ) 2 NONO molecule, its simpler analogue, the (CH 3 ) 2 NONO molecule has also
been studied.
The DFT(B2PLYP) optimised lengths of the N–O1 bonds are presented in
Tables 19.4 and 19.5. For the (CF 3 ) 2 NONO and (CH 3 ) 2 NONO molecules the DFT
(B3LYP)/aug-cc-pVTZ optimised parameters have been used [27]. The N–O1 bond
length varies between 1.404 Å for C 2 H 5 ONO (s-g) and 1.632 Å for (CF 3 ) 2 NONO
(t-a). As the N–O1 bond length in (CF 3 ) 2 NO1NO2 is exceptionally long, it is bound
to exhibit interesting topological features for the N–O1 interaction.
Topological analysis of ELF has not shown any bonding disynaptic basin V(N,O1)
for the interaction between the N and O1 atoms for all studied organic nitrites. Thus,
Table 19.4 N–O1 bond lengths and mean electron populations,
N for the localisaton basins for
the N–O1 bond in a series of organic nitrites, RONO (RO1–NO2)
No
Molecule
Conformer
r(N–O1)
[Å]
V(O1)
[e]
V(N)
[e]
V(N,O1)
[e]
1
CH 3 O1NO
syn
1.408
0.50
0.57
–
anti
1.432
0.35
0.52
–
2
C 2 H 5 O1NO
syn-gauche
1.404
0.51
0.58
–
syn-trans
1.411
0.48
0.57
–
trans-gauche
1.419
0.43
0.55
–
trans-trans
1.426
0.37
0.53
–
3
C 3 H 7 O1NO
syn
1.405
0.50
0.58
–
anti
1.421
0.42
0.55
–
4
i-C 3 H 7 O1NO
syn
1.408
0.49
0.58
–
anti
1.422
0.38
0.53
–
5
C 4 H 9 O1NO
syn
1.405
0.50
0.58
–
anti
1.421
0.42
0.55
–
6
i-C 4 H 9 O1NO
syn
1.406
0.50
0.57
–
anti
1.428
0.37
0.53
–
7
C 5 H 11 O1NO
syn
1.405
0.38
0.53
–
anti
1.425
0.51
0.58
–
8
(CF 3 ) 2 NO1NO
1)
t-s
1.632
–
–
–
t-a
1.583
–
0.35
–
c-a
1.617
–
–
–
9
(CH 3 ) 2 NO1NO
t-s
1.503
–
0.52
–
t-a
1.459
0.29
0.52
–
c-a
1.466
0.19
0.58
–
c-s
1.460
0.29
0.59
–
The topological analysis of ELF performed at the B2PLYP/aug-cc-pVTZ level and
B3LYP/aug-cc-pVTZ level for (CH 3 ) 2 NO1NO and (CF 3 ) 2 NO1NO molecules
CH 3 ONO—methyl nitrite, C 2 H 5 ONO—ethyl nitrite, C 3 H 7 ONO—propyl nitrite, i-C 3 H 7 ONO—
isopropyl nitrite, C 4 H 9 ONO—butylnitrite, i-C 4 H 9 ONO—isobutylnitrite, C 5 H 11 ONO—amyl nitrite
(3-methylbutyl) nitrite
19 Diversity of the Nature of the Nitrogen-Oxygen Bond …
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