Synthesis and experimental and theoretical characterization of m-fluorosulfinylaniline

Article abstract of DOI:10.1039/c5nj00200a

The synthesis of m-fluorosulfinylaniline together with a tentative assignment of the vibrational, NMR and mass spectra are reported. Quantum chemical calculations predict two stable conformers, with very similar energies, both of which possess in the liquid phase syn structure of the -NSO moiety (syn of the SO double bond relative to the C-N single bond). Both conformers belong to the C_S symmetry group and differ by the relative orientation of the fluorine atom and the NSO group. However, the FT-IR, FT-Raman and NMR spectra do not allow a distinction between these two conformers. The experimentally observed spectral data (FT-IR, FT-Raman, ¹H and ¹³C and GC-mass spectrometry) of the title compound are compared with the spectral data obtained by quantum chemical calculations and the gauge including atomic orbital (GIAO) method (DFT/B3LYP approximation using 6-311+G(df), 6-311++G(df,pd) and cc-pVTZ basis sets). Moreover, natural bond orbital (NBO) analysis is applied for studying the stability of the molecule upon charge delocalization in order to provide an explanation of its electronic properties.

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Synthesis, experimental and theoretical
characterization of m-fluorosulfinylaniline
Cite this: DOI: 10.1039/x0xx00000x
Ana L. Páez Jerez,a Doly M. Chemes,b Edgardo H. Cutin,a Heinz Oberhammerc
and Norma L. Roblesa
Received 00th January 2012,
Accepted 00th January 2012
The synthesis of
mꢀfluorosulfinylaniline together with a tentative assignment of the
vibrational, NMR and mass spectra, are reported. Quantum chemical calculations predict two
stable conformers, with very similar energies, both of which possess in the liquid phase syn
structure of the –N=S=O moiety (syn of the S=O double bond relative to the C‒N single bond).
Both conformers belong to CS symmetry group and differ by relative orientation of the fluorine
atom and the NSO group. However, the FTꢀIR, FTꢀRaman and NMR spectra do not allow a
distinction between these two conformers. The experimentally observed spectral data (FTꢀIR,
FTꢀRaman,1H and 13C and GCꢀMass Spectrometry) of the title compound are compared with
the spectral data obtained by quantum chemical calculations and gauge including atomic
orbital (GIAO) method (DFT/B3LYP approximation using 6ꢀ311+G(df), 6ꢀ311++G(df,pd) and
ccꢀpVTZ basis sets). Moreover, Natural Bond Orbital (NBO) analysis is applied for studying
the stability of the molecule upon charge delocalization in order to provide an explanation of
its electronic properties.
DOI: 10.1039/x0xx00000x
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obvious, being the most electronegative element so far reported.
The opposite effect, via mesomeric delocalization, is evident
Introduction
from the structures shown (see Scheme I).
Nꢀsulfinylamines, R‒N=S=O, constitute a vast family of
organic compounds and despite the fact that they have been
known since the end of the 19th century, they have not been
studied intensively until the second half of the 20th century.
The geometry of these compounds are controversial since
earlier studies suggested
heterocumulene unit [1], but subsequent studies predicted
syn anti structures for this group (syn ) or anti ) of the S=O
a linear configuration of the
/
(
Z
(E
bond with respect to the R‒N bond), the former one being more
stable [2 – 5].
The first aromatic N-sulfinylamine, called N-sulfinylaniline or
N-sulfinylꢀbenzenamine, C6H5‒N=S=O was prepared by
Michaelis et al. in 1890 [6]. For this compound, and later for
other R‒N=S=O compounds, the configurational controversy
about the N=S=O geometry was clarified by the Xꢀray
diffraction and vibrational studies in 1999 [7]. Although about
Scheme I. Different mesomeric structures for monosubstituted
benzene rings.
600 Nꢀsulfinyl compounds are known today [8], only a few
Nꢀ
sulfinylꢀaromaticꢀimines have been characterized and their
reactivity has not yet been completely understood.
While it is assumed that steric hindrance could lead to kinetic
stabilization, the electronic effects, which substituents may
Our recent study of
pꢀfluorosulfinylaniline evidences the
combination of both effects [11] (see Scheme II). From Scheme
II it can be noted that the influence of the halogen atom in a
para position is negligible on the structural and therefore on the
vibrational properties of the N=S=O group: the electron
deficiency occurring for the N=S=O group in para position
with respect to the halogen substituent is compensated by
electron delocalization towards C1 and the experimental
vibrational frequencies strongly resemble those belonging to
the parent unsubstituted sulfinylaniline.
cause in the aromatic
Nꢀsufinyl compounds, have not been
determined [9]. The inclusion of a substituent group/atom in
Nꢀ
sulfinylaniline leads to a variation of charge distribution in the
molecule, with consequent effects on the structural, electronic
and vibrational parameters. Being an electron withdrawing
group [10], the presence of the N=S=O group could lead to the
different mesomeric structures depicted on Scheme I. The
electron withdrawing inductive effect of the fluorine atom is
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The substance is highly hygroscopic and corrosive. NMR spectra
were measured in CDCl3 at 200 MHz for 1H and 50 MHz for 13C on
1
a Varian Unity 200 spectrometer. H NMR: δ = 7.10 (C(4)H), 7.38
(C(5)H), 7.58 (C(6)H), and 7.62 (C(2)H) ppm. 13C NMR: δ = 113.97
and 114.43 (C6); 117.39 and 117.82 (C4); 122.92 and 122.98 (C2);
130.22 and 130.40 (C5); 159.93 (C1) and 164.88 (C3) ppm.
The GC/MS analysis was carried out using a Model Trace GC Ultra
gas chromatograph coupled to a Polaris Q mass spectrometer with an
ionꢀtrap analyzer using a DBꢀ5 capillary column. Splitꢀless injection
was used for this study. The initial temperature of the oven was
60°C. After maintaining that temperature for 3 min, the oven
temperature was increased at a rate of 15°C/min to reach a final oven
temperature of 250°C. The final temperature was maintained for 5
min and the total run time was 10.1 min. Helium was used as carrier
gas. The mass spectrometer was operated in the electron ionization
scan mode (range, m/z: 40ꢀ160). Quantification of the peaks was
based on peak area.
Scheme II. Different mesomeric structures for pꢀ and mꢀ fluoro
substituted sulfinylaniline.
Vibrational spectra. Fig. 1 shows the experimental vibrational
spectrum of m-fluorosulfinylaniline. The FTꢀIR spectrum of the
liquid was recorded in the region 3500–400 cmꢀ1 at room
temperature using a PerkinꢀElmer GX1 Fourier Transform infrared
instrument provided with KRSꢀ5 windows (4 cmꢀ1 spectral
resolution). The FTꢀRaman spectrum of the liquid was recorded at
room temperature in the range 3500–50 cmꢀ1 by employing a diodeꢀ
pump, solid state 532 nm green laser with 9.0 mW power at the
sample for excitation in a Thermoscientific DXR Smart Raman
instrument equipped with CCD detector. The resolution was 1.9285
Raman shift (cmꢀ1) with a grating groove density of 900 lines/mm. A
confocal aperture of 50 ꢁm slit was used and 80 expositions of 6 s
were accumulated for the sample in order to achieve sufficient signal
to noise ratio.
In this work, we present the structural, conformational and
vibrational analysis of m-fluorosulfinylaniline on the basis of a
detailed characterization (1H and 13C NMR, COSY, HSQC and
GCꢀChromatography) and
a tentative assignment of the
vibrational spectra (FTꢀIR and FTꢀRaman) supported by
quantum chemical calculations at different levels of theory. The
present study allows us to demonstrate the effects of both,
N=S=O moiety and fluorine substituents, on the properties of
the compound by placing the fluorine atom meta with respect to
the sulfinyl group. Due to the bent geometry of the N=S=O
group, I and II structures would be equal only if the C‒N=S=O
moiety were linear. Therefore, two different conformers with
very similar energies can be expected (see Scheme III).
Scheme III. Structures I and II of mꢀfluorosulfinylaniline.
Materials and Methods
Experimental
Synthesis and characterization. According to the method proposed
by Michaelis for the synthesis of R‒N=S=O compounds [6], m-
fluorosulfinylaniline was prepared using a 1:2:5 molar relation of the
corresponding fluorinated aniline, thionyl chloride and benzene as
the reaction solvent, respectively. m-fluoroaniline (3.47 g , 31 mmol)
and benzene (13.20 g , 169 mmol) were placed in a closed three neck
round bottom flask equipped with a Liebig condenser which was
sealed with a CaCl2 trap. Thionyl chloride (9.80 g , 82 mmol) was
added drop wise to the mixture. To prevent the interaction with air
humidity, the reaction was carried out in nitrogen atmosphere. A
vigorous reaction took place and aniline hydrochloride precipitated.
The reaction mixture was continuously stirred and heated for 7 hours
at 80‒85 °C until a clear solution was obtained. The dark yellow to
green liquid mixture obtained was purified by several distillation
cycles in order to obtain a greenꢀyellowish liquid as the final product
Fig. 1. Experimental infrared and Raman spectra of
mꢀ
fluorosulfinylaniline. Top: infrared spectrum of a liquid sample
held between KRSꢀ5 windows; bottom: room temperature
Raman spectrum of a liquid sample.
Computational details
All quantum chemical calculations were performed using the
GAUSSIAN03 program [12]. The methods employed are based
on the gradient corrected Density Functional Theory (DFT)
with the threeꢀparameter hybrid functional (B3) [13a] for the
exchange part and the LeeꢀYangꢀParr (LYP) correlation
function [13b]. The calculations were carried out using 6ꢀ
311+G(df), 6ꢀ311++G(df, pd) and ccꢀpVTZ basis sets. Natural
population analyses NBO [14], as implemented in the
1
with ca. 92% yield. Its purity was controlled by H and 13C NMR
spectroscopy, GCꢀMass Spectrometry, IR and Raman spectroscopy.
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GAUSSIAN03 program, were performed together with the
Gaugeꢀincluding atomic orbital (GIAO) method [15].
Results and Discussion
Quantum chemical calculations analysis
Stable conformers with different orientation around the N=S
double bond are expected for m-fluorosulfinylaniline, defined
as syn and anti according to the orientation of the S=O bond
with respect to the C‒N bond. However, calculations reported
for the parent sulfinylaniline and some other substituted
sulfinylanilines [2‒7] demonstrate that only the syn form is
observed in the liquid phase. The potential energy function for
rotation around the N=S bond of m-fluorosulfinylaniline was
determined by structure optimizations at fixed dihedral angles
C‒N=S=O in steps of 30°. Calculations at the B3LYP/6ꢀ311+G
(df) and B3LYP/ccꢀpVTZ approximations predicted the syn
structure as the global minimum and a local minimum with anti
geometry, about 7 Kcal.molꢀ1 higher in energy. Subsequent full
optimizations and frequency calculations at these two minima
Fig. 2
fluorosulfinylaniline.
. Molecular model of the syn conformer of mꢀ
The higher stability of the sterically unfavorable syn
conformation of the C‒N=S=O group observed for all
sulfinylanilines reported hitherto may be rationalized by orbital
interactions. A Natural Bond Orbital (NBO) analysis performed
at the DFT/B3LYP/6ꢀ311+G (df) level of theory suggests that
two orbital interactions between nitrogen and sulfur lone pairs
with vicinal antibonding orbitals, i.e. lp (N) →σ* (S‒O) and lp
(S) →σ* (C‒N) (anomeric effects) stabilize the syn conformer
relative to the anti structure. The interaction energies of 15.3
and 9.8 kcal.molꢀ1 in the syn conformer are much stronger than
the corresponding interaction energies in the anti form of only
6.8 and 1.2 kcal.molꢀ1, respectively. These anomeric
interactions override the higher steric interactions in the syn
form and lead to a thermodynamic preference of the syn
conformer. Fig. 3 depicts the molecular orbitals involved in the
relevant orbital interactions.
resulted in ꢂG° (anti
basis sets, respectively.
–
syn) = 6.87 and 6.64 Kcal.molꢀ1 for both
Considering the orientation of the fluorine atom with respect to the
N=S=O group, two different syn isomers of the title compound may
be obtained from the reaction of m-fluoroaniline and SOCl2 (see
Scheme III). The potential energy function for rotation around the
C‒N bond shows two minima with very similar energies for
structures I and II with a rotational barrier of ca. 5 kcal.molꢀ1.
Subsequent full optimizations and frequency calculations of these
two minima resulted in ꢂG° (II – I) = 0.04 Kcal.molꢀ1.
Table
1. Calculated geometric parameters for the m-
fluorosulfinylaniline.a
Structural
mꢀfluorosulfinylaniline
parameters
B3LYP/
6ꢀ311++G(df,pd)
1.347
1.081
1.406
1.383
1.390
1.389
1.540
1.484
119.6
132.2
119.8
118.4
124.3
115.9
118.5
B3LYP/
ccꢀpVTZ
1.347
1.080
1.405
1.382
1.389
1.391
1.535
1.478
119.9
131.8
119.7
118.4
124.3
116.0
118.5
0.0
C‒F
C‒H
C1‒C2,6
C2,5‒C3,6
C4‒C3,5
C1‒N
N=S
S=O
N=S=O
C1‒N=S
C2‒C1‒C6
C3‒C4‒C5
C2‒C1‒N
C6‒C1‒N
F‒C3‒C2,4
C1‒N=S=O
0.0
aBond lengths in Å and angles in degrees. Mean values are
given for parameters that are not unique. For numbering atoms
see Fig. 2.
Fig. 3. Relevant NBO orbitals [B3LYP/6ꢀ311+G(df)] for the
syn (upper) and anti (lower) conformers of mꢀ
fluorosulfinylaniline.
With this small energy difference both conformers are expected to be
present in almost equal amounts. Table 1 lists the structural
parameters of the syn (I) form of m-fluorosulfinylaniline. Parameters
of the syn (II) conformer are very similar. (see Fig. 2).
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Vibrational Analysis
Table 2 shows a tentative assignment of the 3N – 6 = 36 normal
vibrational modes expected for ꢀfluorosulfinylaniline. The
m
analysis of the experimental infrared and Raman spectra of a
liquid sample was supported by Density Functional Theory
calculations with the 6ꢀ311++G(df,pd) and ccꢀpVTZ basis sets
using suitable scale factors to improve the theoretical
frequencies predicted, according to the results reported by
Wojciechowski et al [16] (see Fig. 1). In addition, theoretical
15N substitution was used to help identifying the vibrational
modes expected for the N=S=O group. From the experimental
and theoretical spectra, the distinction between conformers I
and II could not be established because the differences in
vibrational frequencies are too small to confirm a given
particular structure. Reported data for the parent sulfinylaniline
[7], pꢀfluorosulfinylaniline [11] and the reactant
mꢀ
fluoroaniline [17] were also taken into account. Figs. 4 and 5
show graphical comparisons between the experimental and
theoretical vibrational spectra.
Fig. 4. Experimental and theoretical infrared spectra of
mꢀ
Our laboratory recently reported the conformational and
fluorosulfinylaniline. Top: theoretical gas phase spectrum
calculated at the B3LYP/6ꢀ311++G(df,pd) level of theory;
bottom: room temperature infrared spectrum of a liquid sample.
vibrational properties of
pꢀfluorosulfinylaniline [11]. Its
vibrational spectra showed no remarkable influence of the
fluorine atom on the frequencies of the N=S=O group in
comparison with the parent sulfinylaniline. In contrast, previous
calculations performed for o- and
mꢀfluorosulfinilaniline
indicated that the influence of a fluorine atom depends on its
position in the aromatic ring and on the vibrational mode
considered. The asymmetric stretching of the N=S=O group in
the
belonging to the
(B3LYP/6ꢀ311+G(df)), while the corresponding mode for the
ꢀisomer was predicted about 14 cmꢀ1 higher in frequency
o
ꢀderivative was predicted in close agreement with that
p
ꢀsubstituted compound, around 1334 cmꢀ1
m
terms. From the hypothetic resonance structures depicted in
Scheme II it is possible to visualize that a fluorine atom in para
position might contribute to compensate the electronic
deficiency due to the electron withdrawing N=S=O group.
Some of the structures contributing to the hybrid show partial
single N‒S bonds, consequently, the N=S=O vibrational modes
for the
pꢀ, and possibly oꢀ, substituted isomers were expected at
lower frequencies than those corresponding to the
m
ꢀ
fluorosulfinylaniline. We are now able to confirm part of that
assumption, since the experimental spectra obtained for the title
compound show bands at 1314 and 1036 cmꢀ1 (IR) and 1313
and 1038 cmꢀ1 (Raman), which were assigned to the N=S=O
asymmetric and symmetric stretchings, respectively.
Theoretical calculations confirmed this assignment, predicting a
5 cmꢀ1 downshift upon isotopic substitution with 15N atom. It
still remains to be confirmed that the experimental vibrational
Fig. 5. Experimental and theoretical Raman spectra of
mꢀ
fluorosulfinylaniline. Top: theoretical gas phase Raman
spectrum calculated at the B3LYP/6ꢀ311++G(df,pd) level of
theory (532 nm excitation laser); bottom: room temperature
spectrum of a liquid sample.
However, calculations performed for this series with the
B3LYP/6ꢀ311+G(df) approximation predict an opposite trend,
spectra of oꢀfluorosulfinylaniline agree with the assumptions
stated above [18].
being the C‒F bond belonging to the
pꢀand oꢀderivatives being
stronger than that of the
m
ꢀisomer, 1261, 1262 and 1228 cmꢀ1,
respectively . Therefore, the strong signal observed at 1216
cmꢀ1 in the infrared spectra of the title compound was assigned
to this stretching, in good agreement with calculations
performed now with larger basis sets. This assignment may be
rationalized in terms of the opposite withdrawing effects of the
‒NH2 and ‒N=S=O groups [19]. Following the same reasoning,
the C‒N stretching was assigned to the medium/strong signal
placed at 785 cmꢀ1 in the infrared spectrum. The corresponding
fundamental was observed at 822 cmꢀ1 in the infrared spectrum
The inꢀplane deformation of the N=S=O group was assigned to
the signal placed at 634 and 636 cmꢀ1 in the infrared and Raman
spectra, respectively, in agreement with frequencies reported
for
p
ꢀfluorosulfinylaniline.
For the series of
p
ꢀ, oꢀ and mꢀsubstituted fluoroaniline the C‒F
stretching was assigned to the signals at 1225, 1270 and 1288
cmꢀ1, respectively in the infrared spectra [17]. Consequently,
the shoulder observed at ca. 1227 cmꢀ1 in the infrared spectrum
of the pꢀsubstituted derivative.
of pꢀfluorosulfinylaniline was attributed to that fundamental.
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Table 2. Experimental and calculated wavenumbers of the
mꢀfluorosulfinylaniline and tentative assignments of main fundamental
vibrational modes.
Experimental b
IR(liq.) Raman(liq.)
Theoretical valuesc
Scaled
6ꢀ311++G(df,pd)
Mode Approximate descriptiona
B3LYP/
B3LYP/
ccꢀpVTZ
valuesd
ν1
ν2
C–H Stretch.
C–H Stretch.
3091 m
3072 m
ꢀ
ꢀ
3233(4)[3]
3212(1)[28]
3206(1)[16]
3187(3)[12]
1635(1)[50]
1613(49)[1]
1513(32)[5]
1461(8)[9]
1354(1)[26]
1318(46)[100]
1302(8)[15]
1227(41)[4]
1182(13)[1]
1153(100)[25]
1103(2)[1]
1053(14)[14]
1016(1)[9]
995(<1)[<1]
926( 26)[2]
923(1)[<1]
915(16)[<1]
804(31)[<1]
720(<1)[5]
678(7)[<1]
638(5)[2]
3097
3077
3071
3053
1607
1586
1487
1436
1331
1296
1280
1206
1162
1133
1084
1035
999
3237(6)[4]
3210(3)[35]
3204(2)[19]
3185(5)[15]
1638(2)[52]
1616(67)[1]
1516(46)[6]
1465(12)[10]
1354(1)[32]
1320(67)[100]
1302(14)[15]
1231(57)[3]
1184(39)[3]
1163(100)[31]
1104(4)[1]
1057(13)[13]
1020(<1)[9]
1000(<1)[<1]
930(10)[<1]
930(34)[1]
922(15)[<1]
811(32)[<1]
722(<1)[5]
703(16)[<1]
642(7)[2]
3078 sh
3063m
ꢀ
ν3
C–H Stretch.
ν4
C–H Stretch.
3037 m
1602 m
1584 s
1478 s
1442 w
1314 m
1295 s
1268 m
1216 s
1163 m
1143 m
1082 w
1036 w
1003 w
992 sh
ν5
C–C Stretch.
1601 m
1583 sh
1476 w
1442 w
1313 s
1297 vs
1268 m
1216 vw
1163 m
1140 s
1082 vw
1038 m
1003 m
992 m
ꢀ
ν6
C–C Stretch.
ν7
C–C Stretch. + C–H Def.
C–C Stretch. + C–H Def.
N=S=O Asym. Stretch.
C–C Stretch. + C–H Def.
C–C Stretch.
ν8
ν9
ν10
ν11
ν12
ν13
ν14
ν15
ν16
ν17
ν18
ν19
ν20
ν21
ν22
ν23
ν24
ν25
ν26
ν27
ν28
ν29
ν30
ν31
ν32
ν33
ν34
ν35
ν36
C–F Stretch.
C–H Def.
C–H Def.
C–H Def. + C–C Def. i.p.
N=S=O Sym. Stretch.
C–H Def. + C–C Def. i.p.
Ring Def.
978
C–H Def. o.o.p. + Ring torsion 938 w
910
Ring Def.
908 w
872 m
785 s
719vw
676 vs
634 w
607 w
518 m
486 w
444 w
426 w
ꢀ
908 vw
ꢀ
907
C–H Def. o.o.p.
C–N Stretch.
Ring Def.
899
ꢀ
790
719 vw
ꢀ
708
C – H Def. i.p.
N=S=O Def. i.p.
Ring Def.
666
636 w
607 vw
517 w
486 w
445sh
427 w
343 w
283 w
245 w
194 w
ꢀ
627
627(3)[<1]
525(4)[1]
616
634(3)[<1]
526(5)[1]
Ring Def.
516
Ring Def.
475(<1)[<1]
445(4)[<1]
437(3)[1]
467
479(1)[<1]
446(6)[1]
C – F Def. i.p.
Ring Def.
437
430
438(4)[1]
C–F Def. o.o.p.
Skeletal Def.
N=S=O Def. o.o.p.
Ring Def.
372(5)[<1]
276(6)[1]
366
380(6)[<1]
279(8)[1]
ꢀ
271
ꢀ
244(<1)[<1]
148(1)[<1]
127(1)[<1]
60(<1)[<1]
240
247(<1)[1]
150(2)[<1]
131(1)[<1]
59(<1)[<1]
ꢀ
145
Ring Def.
ꢀ
125
Ring Def.
ꢀ
ꢀ
59
a Stretch.: stretching; Def.: deformation; Asym.: antisymmetric; Sym.: symmetric; sh: shoulder; i.p.: in phase; o.o.p.: out of phase;
b
c
tors.: torsion; s: strong; vs: very strong; m: medium; w: weak; vw: very weak. Relative infrared intensities in parentheses,
d
normalized to 100%; Relative Raman activities between brackets, normalized to 100%. Values scaled according to scaling
factors in Ref. [16].
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NMR Spectra Analysis
Table 3. 1H NMR experimental (200 MHz, CDCl3, Me4Si) and
Since the barrier of rotation around the C‒N single bond is low calculated data of
(about 5 Kcal/mol, see above) the change of conformers I and II
mꢀfluorosulfinylaniline.
Ha
Chemical shift (δ) (ppm)
Experimental
C(4)H 7.10 (1H, m, J2,F 9.20, J2,3 6.34, 6.89
J2,4= J2,1 2,30)
due to rotation around this bond is much faster than the NMR
Theoreticalb
time scale and only mean shift values are observed. Complex
signals exist in the 7.00 and 7.70 ppm, and 113 and 165 ppm
regions of the 1H NMR and 13C NMR spectra of m-
fluorosulfinylaniline, respectively. The assignment proposed
(see Tables 3 and 4) was based on results reported for other
similarly substituted aromatic molecules containing fluorine
and electron withdrawing groups in meta position, as well as on
data reported for unsubstituted sulfinylaniline [7]. It is well
known that the presence of electron withdrawing groups/atoms
lead to deshielding of the protons in resonance and the
consequent increase of the chemical shift values. Therefore, the
influence of the fluorine atom and the N=S=O group must be
considered. Thus, the signals observed at 7.10, 7.38, 7.58 and
C(5)H 7.38 (1H, dd, J3,2=J3,4 6.34)
7.14
C(6)H 7.58 (1H, ddd, J4,3 6.34, J4,2=J4,1 6.94
2,30)
C(2)H 7.62 (1H, m, J1,F 6.91, J1,2=J1,4 8.53
2.30)
For atom numbering see Fig. 2; b Calculated chemical shifts
a
(GIAO method) using B3LYP/6ꢀ311+G(df) approximation.
1
7.62 ppm of the H NMR spectrum were attributed to C(4)H,
relative abundance) accounts for a m/z 157 relation, which was
attributed to the molecular ion. Consequently, the peak at m/z
158 was assigned to the protonated form of the molecular ion.
No evidence of the fragmentation of the C‒halogen bond was
found in the spectrum (ca. m/z 138 peak), possibly due to C‒F
bond is stronger than any other bond. The weak peak at m/z 95
was assigned to the [C6H4F]+ fragment while that observed at
m/z 76 may be attributed to [C6H4]+ fragment. The clusters of
ions found in the region of m/z 51, 52, 63, 65, 77, 78, 89ꢀ92 are
wellꢀknown fragments arising from the decomposition of
aromatic structures [20].
C(5)H, C(6)H and C(2)H, respectively (see Fig. 2). This
assignment was supported by theoretical calculations at the
B3LYP/6ꢀ311+G(df) level of theory with the gaugeꢀincluding
atomic orbital (GIAO) method, one of the most common
approaches for calculating nuclear magnetic shielding tensors
[15]. HSQC and COSY experimental spectra of
mꢀ
fluorosulfinylaniline were useful for the assignment, showing
H‒H and C‒H correlations, respectively. The HSQC spectrum
of
mꢀfluorosulfinylaniline showed crossꢀpeaks between the
signals assigned to C(5)H and C5, C(6)H and C6, C(4)H and
C4 and C(2)H and C2 meanwhile the COSY spectrum showed
crossꢀpeaks between the signals assigned to C(4)H and C(5)H,
and C(5)H with C(6)H. The characteristic time scale of NMR
spectroscopy does not allow discerning between conformers I
and II in the experimental spectra.
Table 4. 13C NMR experimental (50 MHz, CDCl3, Me4Si) and
calculated data of
m
ꢀfluorosulfinylaniline.
C a
Chemical shift
(δ) (ppm)
Experimental
113.97, 114.43
117.39, 117.82
122.92, 122.98
130.22, 130.40
159.93
Theoreticalb
128.0
122.7
119.05
133.1
152.3
GC/MS Analysis
C(6)
C(4)
C(2)
C(5)
C(1)
C(3)
The intense signal observed at 7.81 min (91.8% relative area
and 157 molecular weight) in the totalꢀion chromatogram
accounts for the presence of
additional peak found at time retention 7.02 min (3.91%
relative area and 111 molecular weight) belongs to the reactant
mꢀfluorosulfinylaniline while the
164.88
169.9
a
b
For atom numbering see Fig. 2; Calculated chemical shifts
(GIAO method) using B3LYP/6ꢀ311+G(df) approximation.
m
ꢀfluoroaniline. The major fragmentation patterns of fragments
of interest are proposed in Fig. 6. The base peak of the mass
spectra of ꢀfluorosulfinylaniline (mass numbers (m/z) versus
m
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ARTICLE
DOI: 10.1039/C5NJ00200A
frequency shifts of functional groups in an aromatic ring
depends on its position in the aromatic ring and on the
vibrational mode considered.
Acknowledgements
Authors acknowledge CONICET (Consejo Nacional de
Investigaciones Científicas y Técnicas) and UNT (Universidad
Nacional de Tucumán) for the financial support. Authors also
kindly acknowledge staff from LISA (Laboratorio de
Investigación y ServiciosAnalíticos) for NMR and GC/MS
measurements.
References
aINQUINOA (CONICETꢀUNT) Ayacucho 471, (4000) Tucumán,
República Argentina.
bInstituto de Química Física, Facultad de Bioquímica, Química
y
Farmacia, Universidad Nacional de Tucumán, San Lorenzo 456, (4000)
Tucumán, República Argentina.
cInstitut für Physikalische und Theoretische Chemie, Universität
Tübingen, 72076 Tübingen, Germany.
1
2
K. Krieze and G. van Koten, Recl. Trav. Chim. Pays-Bas., 1980, 99,
145.
Fig. 6. Major fragmentation patterns of m/z peaks for mꢀ
fluorosulfinylaniline.
a) Hꢀ.G. Mack, H. Oberhammer and C.O. Della Vedova, J. Mol.
Struct.1992, 265, 347; b) K. I. Gobbato, C.O. Della Vedova and H.
Oberhammer, J. Mol. Struct. 1995, 350, 227.
3
a) R. M. Romano and C. O. Della Védova, J. Mol. Struct., 1998, 440,
43; b) R. M. Romano, C. O. Della Vedova and A. Pfeiffer, J. Mol.
Struct., 1998, 446, 127.
Conclusions
A new member of the sulfinylaniline family of compounds has
been prepared by reacting ꢀfluoroaniline and SOCl2. The
4
5
R.M. Romano and C.O. Della Védova, J. Mol. Struct.,2000, 522, 1.
G. Cerioni, N. Culeddu and A. Piumitallo, Tetrahedron, 1993, 49,
2957.
m
highly reactive and corrosive liquid compound obtained was
characterized by using nuclear magnetic resonance
spectroscopy (1H and 13C), gasꢀchromatography/mass
spectrometry, vibrational spectra and quantum chemical
calculations. Although at least two stable conformers might be
expected around the N=S bond (syn and anti of the C–N bond
with respect to the S=O bond) and also two stable structures
were predicted taking into account the orientation of the
N=S=O and fluorine substituents, all experimental spectra
evidence the presence of a single conformer, since no additional
signals were observed to account for several forms in
equilibrium at room temperature. Theoretical calculations using
B3LYP with different basis sets confirmed that only the syn
conformation of the N=S=O moiety can be observed in the
liquid phase, predicting global CS symmetry of this compound
in agreement with the properties observed for the parent
sulfinylaniline. The unexpected syn configuration adopted by
all R‒N=S=O compounds reported so far, might be rationalized
in terms of orbital interactions. In fact, larger interaction
6
7
a) A. Michaelis andR. Hertz, Ber. Deutsch. Chem. Ges., 1891, 24,
745; b) A. Michaelis andO. Storbeck, Liebigs Ann. Chem.,1893, 274,
187.
a) R. M. Romano, C. O. DellaVédova and R. Boese, J. Mol. Struct.
,
1999,475, 1; b) R. M. Romano, C. O. Della Védova and P.
Hildebrandt, J. Mol. Struct., 1999, 508, 5; c) R. Meij, A. Oskam and
D. J. Stufkens, J. Mol. Struct., 1979,51, 37.
8
9
K. O. Christe, M. Gerken, R. Hages, S. Schneider, T. Schroer, F.S.
Tham and A. Vij, Solid State Sci., 2002, 4, 1529.
E. V. Ivanova and H. M. Muchall, J. Phys. Chem. A, 2011, 115, 3095.
10 N. C. Collins and W. K. Glass, Spectrochim. Acta A,1974, 30, 1335.
11 A. L. Páez Jerez, A. Flores Antognini, E. H. Cutin and N. L. Robles,
Spectrochim. Acta A,2015, 137, 300.
12 M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A.
Robb, J. R. Cheeseman, J. A. Montgomery Jr., T. Vreven, K. N.
Kudin, J. C. Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V.
Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G.
A.Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R.
Fukuda, J. Hasegawa,M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H.
Nakai, M. Klene, X. Li, J. E. Knox,H. P. Hratchian, J. B. Cross, V.
Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E.Stratmann, O.
Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski,
energies were predicted for the syn configuration of
mꢀ
fluorosulfinylaniline compared to the anti structure, according
to Natural Bond Orbital analysis. Thus, the thermodynamic
preference of the syn form can be rationalized as a result of the
influence of stabilizing anomeric interactions.
From the analysis of the vibrational frequencies of the
pꢀ and
m
ꢀfluorosulfinylaniline compounds reported up to the moment,
we may state that the influence of a fluorine atom on the
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ARTICLE
VJieowuArrtnicalelONnlainme e
DOI: 10.1039/C5NJ00200A
P.Y.Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J. Dannenberg,
V. G. Zakrzewski, S.Dapprich, A. D. Daniels, M. C. Strain, O.
Farkas, D. K. Malick, A. D. Rabuck, K.Raghavachari, J. B.
Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S. Clifford,
J.Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I.
Komaromi, R. L.Martin, D. J. Fox, T. Keith, M. A. AlꢀLaham, C. Y.
Peng, A. Nanayakkara, M.Challacombe, P. M. W. Gill, B. Johnson,
W. Chen, M. W. Wong, C. Gonzalez, J. A.Pople, Gaussian Inc
,
Wallingford, CT, Revision E.01, 2007.
13 a) A.D. Becke, J. Chem. Phys., 1993, 98, 5648; b) C. Lee,W. Yang
and R.G. Parr, Phys. Rev.B, 1988, 37, 785.
14 A. E. Reed, L. A. Curtis and F. Weinhold, Chem. Rev.,1988, 88, 899.
15 a) J. R. Cheeseman, G. W. Trucks, T. A. Keith, M. J. Frisch, Chem.
Phys., 1996, 104, 5497; b) J. R. Cheeseman, M. J. Frisch, F. J. Devlin
and P. J. Stephens, Chem. Phys. Lett.,1996, 252,211.
16 P. M. Wojciechowski and D. Michalska, Spectrochim. Acta A, 2007,
68, 948.
17 M. A. Shashidhar and K. Suryanarayana Rao. Spectrochim. Acta A
,
1970, 26, 2373.
18 A. L. Páez Jerez, D. M. Chemes, E. H. Cutin, N. L. Robles and H.
Oberhammer, manuscript in preparation
.
19 T. Siodła, W. P. Ozimiński, M. Hoffmann, H. Koroniak and T. M.
Krygowski, J. Org. Chem., 2014, 79,7321.
20 H. Budzikiewicz, C. Djerassi and D. H. Williams, Mass Spectrometry
of Organic Compounds, HoldenꢀDay, San Francisco, CA, 1967.
8 | J. Name., 2015, 00, 1-3
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