TRANSFORMATIONS OF DIPHENYL SULFIDE
273
7.460 ppm and δB 7.225 ppm. The 13C NMR spectrum
exhibits three signals due to tertiary and quaternary
carbon atoms at δ1 135.57 ppm, δ2 128.75 ppm, and
with a 20% sodium hydroxide solution, the reaction
mixture was cooled to room temperature, and the
aqueous layer was separated from the organic layer.
The latter was evaporated to reduce the volume by δ3 127.70 ppm.
three to four times and cooled in a refrigerator to
In addition, the samples were investigated by the
+10°C. The precipitated thianthrene crystals were fil-
tered off on a Buchner funnel, washed with the cold
solvent, and recrystallized from a mixture of benzene
with ethyl alcohol (1 : 1 by volume). Some syntheses
were carried out in a solventless mode in a small excess
of DPS. The thianthrene yield was calculated with
respect to the theoretical yield defined by the equa-
tion:
technique of gas chromatography–mass spectrometry
(GC–MS) using a Perkin-Elmer chromatograph with
a Perkin-Elmer CLARUS 500 mass-selective detector
operating in the electron ionization mode (energy,
70 eV). The analysis conditions were as follows: an
HP-5MS chromatographic capillary column with l =
30 m, d = 0.32 mm, and a polymethylsiloxane film
thickness of 0.20 μm; an injector temperature of
280°C, a detector interface temperature of 290°C; the
oven temperature programmed as holding for 3 min at
70°C, heating at a rate of 4°C/min to 290°C, and
holding at this temperature for 20 min; and a carrier
gas (helium) flow rate of 1.0 mL/min. Data acquisi-
tion and processing were carried out using the software
AMDIS V2.66; chromatographic peaks were identi-
fied with the use of NIST 2.0f electronic mass spectra
libraries updated on July 23, 2008.
(
)
2 C6H5 S + AlCl3
2
+H2O
−HCl
⎯⎯⎯⎯→ C12H8S2 + Al(OH)Cl2 + 2C6H6.
A similar procedure was used to run the reaction
with DPA or DPE and the DPS + DPA or DPS +
DPE cross-synthesis (see table).
Analysis
The most intense peaks of fragment ions at
m/z 184, 171, 108 in the thianthrene spectrum corre-
spond to cations containing a sulfur atom: C12H8S+,
The composition and amount of the components
of the reaction mixtures were determined by GLC on
a Chromatech Kristall 2000 M instrument using a
capillary column with l = 15 m, d = 0.32 mm, and a
polymethylsiloxane film thickness of 0.20 μm. The
injector and detector temperatures were 290 and
300°C, respectively; the column temperature was pro-
grammed as follows: holding for 5 min at 70°C, heat-
ing at a rate of 4°C/min to 290°C, and holding at this
temperature for 20 min. The carrier gas was helium
used at a flow rate of 1.2 mL/min.
C11H7S+, and C6H4S+, indicating the dissociation of
C–S bonds during the fragmentation of the molecular
ion, m/z (Irel, %): 216 (100), 184 (83.9), 171 (23.2), 152
(7.1), 139 (17.9), 127 (3.6), 108 (14.3), 95 (8.9), 86
(7.1), 69 (19.6). Mass spectrum of o-di(phen-
ylthio)benzene, m/z (Irel, %): 294 (100), 261 (3.6), 217
(7.1), 185 (78.6), 171 (7.1), 152 (28.6), 139 (10.7), 109
(14.3), 95 (7.1), 77 (26.8). The fragmentation of the
molecular ion of bis(phenylthio)diphenyl sulfide
involves the elimination of first the thiophenyl and
then the phenyl radical followed by the removal of the
sulfur atom, m/z (Irel, %): 402 (11.1), 293 (100), 281
(6.7), 216 ( 55.6), 184 (71.1), 171 (11.1), 152 (13.3), 139
(11.1), 109 (8.9), 96 (6.7), 77 (8.9). In the mass spec-
trum of phenylthiothianthrene, peaks of fragment ions
at m/z = 215, 171, 145 have a high relative abundance,
confirming the initial detachment of the thiophenyl
radical. Mass spectrum, m/z (Irel, %): 324 (74.5), 290
(17.6), 246 (5.9), 215 (100), 171 (51.0), 145 (49.0), 139
(13.7), 108 ( 5.9), 95 (9.8), 77 (13.7).
IR spectra were recorded on a Perkin-Elmer Spec-
trum 100 Fourier-transform IR spectrometer in the
attenuated total reflectance mode using a Miracle sin-
gle-reflection ATR accessory—“strong” apodization,
4.00 cm−1 resolution. UV spectra were recorded in
ethanol with an SF 2000 spectrophotometer over the
wavelength range of 200–800 nm. The UV spectrum
of thianthrene exhibits an enhanced intensity and a
bathochromic shift of the long-wavelength absorption
band due to n–π* transition with λmax = 258 nm,
which is associated with the +M effect of the second
sulfur atom having the lone electron pair, as compared
with the DPS spectrum. A broad intense absorption
band with λmax = 205 nm corresponds to the
HOMO → LUMO π–π* transition.
Mass spectrum of dibenzo-1,4,5,8-tetrathioan-
thracene, m/z (Irel, %): 354 (100), 322 (54.2), 290
(89.6), 277 (18.8), 258 (10.4), 245 (8.3), 214 (4.2), 177
(18.8), 169 (8.3), 160 (27.1), 154 (10.4), 145 (35.4), 138
(43.8), 125 (8.3), 93 (10.4), 69 (25.0).
To establish the structure of the samples, 13C NMR
1
and H NMR spectra in deuterochloroform (CDCl3)
were recorded on a Bruker AVACE AV300 instrument
operating at 75- and 300-MHz frequencies, respec-
tively, using tetramethylsilane as the standard. The
thianthrene structure was confirmed by the UV, IR,
and NMR spectral methods. The 1H NMR spectrum
of thianthrene displays signals of two groups of aro-
matic protons as symmetrical double doublets at δA
The melting points of the compounds were deter-
mined with a Stuart Scientific SMP30 instrument.
The following compounds were identified by the GC–
MS technique as impurities in the reaction mixtures of
synthesis runs 5, 8, and 9 (wt %): run 5—o-di(phen-
ylthio)benzene (4.3, dark brown liquid), phenylthio-
thianthrene (two isomers, 0.8 and 2.0), and dibenzo-
PETROLEUM CHEMISTRY Vol. 57 No. 3 2017