Preparation of 3,3-di-tert-butylthiirane trans-1,2-dioxide and its reaction with a platinum(0) complex to give a (disulfenato)platinum(II) complex: Regioselectivity of the oxidation of a related (sulfenato-thiolato)platinum(II) complex

Article abstract of DOI:10.1002/ejic.200700824

A three-membered vic-disulfoxide, 3,3-di-tert-butyldithiirane trans- 1,2-dioxide (8), was synthesized by oxidation of the corresponding dithiirane 1-oxide 15 in high yield. Treatment of 8 and 15 with a platinum(0) complex, [(Ph₃P)₂Pt(η²-C₂H₄)], yielded the (disulfenato)Pt^II complex 18 and the (sulfenato-thiolato)Pt^II complex 14, respectively, in high yields. Oxidation of the sulfenato-thiolato complex 14 with an acetone solution of dimethyldioxirane (DMD) took place at the sulfenato sulfur atom to yield the (sulfinato-thiolato)Pt^II complex 19, while the oxidation with CF ₃CO₃H occurred at the thiolato-sulfur atom leading to the disulfenato complex 18. Oxidation of 14 with MCPBA formed both 18 and 19. The position of oxidation on 14 with DMD was dependent on the acidity of a coexisting acid. Thus, oxidation of 14 with DMD/CF₃CO₂H provided 18 and that with DMD/PhCO₂H gave 19. Oxidation of 14 with an excess amount of DMD yielded the (disulfonato)Pt^II complex 20. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.

Full text of DOI:10.1002/ejic.200700824

FULL PAPER
DOI: 10.1002/ejic.200700824
Preparation of 3,3-Di-tert-butylthiirane trans-1,2-Dioxide and Its Reaction with
a Platinum(0) Complex To Give a (Disulfenato)platinum(II) Complex:
Regioselectivity of the Oxidation of a Related (Sulfenato–thiolato)platinum(II)
Complex
Akihiko Ishii,*[a] Masayuki Ohishi,[a] and Norio Nakata[a]
Dedicated to Professor Renji Okazaki on the occasion of his 70th birthday
Keywords: Platinum / Dithiirane / vic-Disulfoxide / Oxidative addition / Oxidation
A
three-membered vic-disulfoxide, 3,3-di-tert-butyldithi-
thiolato-sulfur atom leading to the disulfenato complex 18.
Oxidation of 14 with MCPBA formed both 18 and 19. The
position of oxidation on 14 with DMD was dependent on the
acidity of a coexisting acid. Thus, oxidation of 14 with DMD/
CF3CO2H provided 18 and that with DMD/PhCO2H gave 19.
Oxidation of 14 with an excess amount of DMD yielded the
(disulfonato)PtII complex 20.
irane trans-1,2-dioxide (8), was synthesized by oxidation of
the corresponding dithiirane 1-oxide 15 in high yield. Treat-
ment of 8 and 15 with a platinum(0) complex, [(Ph3P)2Pt(η2-
C2H4)], yielded the (disulfenato)PtII complex 18 and the (sul-
fenato–thiolato)PtII complex 14, respectively, in high yields.
Oxidation of the sulfenato–thiolato complex 14 with an ace-
tone solution of dimethyldioxirane (DMD) took place at the
sulfenato sulfur atom to yield the (sulfinato–thiolato)PtII com-
plex 19, while the oxidation with CF3CO3H occurred at the
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2007)
Introduction
vic-Disulfoxides [RS(O)S(O)R] have long been recog-
nized as unstable intermediates in the electrophilic oxi-
dation of disulfides[1–3] until our success in 1999 with the
isolation and unambiguous structure determination of tet-
rathiolane 2,3-dioxide 1, which has a –S(O)–S(O)– bond.[4,5]
Since then we have reported on isolable vic-disulfoxides 2–
4.[6–10] 3-(1-Adamantyl)-3-tert-butyldithiirane trans-1,2-di-
oxide (4) is the first three-membered vic-disulfoxide synthe-
sized by the oxidation of the corresponding dithiirane 1-
oxide 5 with an acetone solution of dimethyldioxirane
(DMD) [Equation (1)].[9] An interesting reaction of 4 is its
decomposition in refluxing chloroform as shown in
Scheme 1 to give sulfine 6 and sulfur monoxide (SO) by the
main path. SO was trapped with thioketone 7, generated
from a minor path, to provide dithiirane 1-oxide 5
(Scheme 1). The thermal decomposition was investigated in
detail experimentally and theoretically, and, for the theoret-
ical study, 3,3-di-tert-butyldithiirane trans-1,2-oxide (8) was
employed as the model compound of 4.[9]
In this paper we report on the synthesis and some reac-
tions of vic-disulfoxide 8, focusing, in particular, on the
platinum complex of 8 and the related compounds. While
the oxidative addition of several types of sulfur–sulfur
bonds in cyclic sulfur compounds to platinum(0) complexes
is a topic of recent research,[11–24] it has not been clarified
whether vic-disulfoxides bring about a similar oxidative ad-
dition to platinum(0) complexes to provide (disulfenato)PtII
complexes.[20] We have reported the reaction of dithiirane
1-oxides with [(Ph3P)2Pt(η2-C2H4)] to provide the corre-
[a] Department of Chemistry, Graduate School of Science and
Engineering, Saitama University
Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
Fax: +81-48-858-3700
E-mail: ishiiaki@chem.saitama-u.ac.jp
Supporting information for this article is available on the
WWW under http://www.eurjic.org or from the author.
sponding (sulfenato–thiolato)PtII complexes
9
[Equa-
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Scheme 1. Thermal decomposition of 3-(1-adamantyl)-3-tert-butyl-
dithiirane trans-1,2-dioxide (4).
Results and Discussion
tion (2)].[18,19] The oxidation of (dithiolato)MII (M = Ni,
Pd, Pt) complexes with molecular oxygen or hydrogen per-
oxide was studied extensively in relation to their air sensitiv-
ity.[25–39] We recently reported the regioselective oxidation
of (dithiolato)PtII complex 10 and its oxides with DMD
under neutral conditions [Equation (3)].[24] We observed
that the oxidation of the (sulfenato–thiolato)PtII complex
11 led to the (sulfinato–thiolato)PtII complex 12 and not
the (disulfenato)PtII complex 13. This regioselectivity was
rationalized in terms of the fact that the sulfenato sulfur is
more reactive than the thiolato sulfur because of the back-
donation of the platinum atom as Schenk proposed for the
reaction of CpRuL2[S(O)R] (L = phosphane ligands) with
DMD [Equation (4)].[40] In order to verify whether this re-
gioselectivity of oxidation is true for the present system and
whether the regioselectivity is influenced by the presence or
absence of acid, the related (sulfenato–thiolato)PtII complex
14 was prepared and subjected to an oxidation study.
Di-tert-butyldithiirane 1-oxide (15) was prepared by the
reaction of di-tert-butyldiazomethane with S8O in 12%
yield,[41] and was treated with DMD (5.9 molar equiv.) in
1
dichloromethane at –20 °C. The H NMR spectrum of the
reaction mixture showed the formation of the desired 1,2-
dioxide 8, di-tert-butyl thioketone S-oxide (sulfine) (16),
and di-tert-butyl ketone in a ratio of 89:10:1 (Scheme 2).
The high yield of 8 indicated that the over-oxidation to give
the trioxides and higher oxides hardly occurred under these
conditions. The dioxide 8 was isolated by recrystallization
at –20 °C in 79% yield as pale-yellow plates. The oxidation
with m-chloroperbenzoic acid (MCPBA) (6 molar equiv.) at
–20 °C proceeded slowly to give 8 in 31% yield together
with sulfine 16 (6%) and the starting compound 15 (63%)
(1H NMR integral ratio). In the H NMR and 13C NMR
1
spectra, the two tert-butyl groups of 1,2-dioxide 8 are equiv-
alent, and in the 13C NMR spectrum, the dithiirane carbon
resonated at δ = 105.9 ppm, shifted to the lower field by
19.6 ppm than that of the 1-oxide 15 (δ = 86.3 ppm).
The structure of 1,2-dioxide 8 was determined by X-ray
crystallography (Figure 1). In the crystal structure of 8 the
C2 symmetry axis runs through the center of the S–S bond
and the dithiirane carbon. The S–S bond length
[2.2307(11) Å] is slightly longer than that of 4 [2.242(2) Å],
and the dihedral angle O–S–S–O (149.0°) is very similar to
that of 4 [149.6(3)°]. The angle between the two tert-butyl
groups widens to 122.7(2)° as observed in 4 [123.6(5)°].[9]
1,2-Dioxide 8 was stable in the crystalline state at room
temperature for a long time, but decomposed gradually in
chloroform at room temperature to give sulfine 16 almost
quantitatively after 9 d. Heating 8 in refluxing chloroform
for 2 h yielded sulfine 16 (78%), dithiirane 1-oxide 15
(14%), and thioketone 17 (4%) [Equation (5)]. The reac-
tions depicted in Scheme 1 can be applied to explain the
Scheme 2. Synthesis of 3,3-di-tert-butyldithiirane trans-1,2-oxide (8).
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(Disulfenato)PtII Complex
coupling constant value is comparable to those for phos-
phorus atoms trans to the S=O groups.[12–24] The absorp-
tion due to the S=O stretching vibration is observed at
1097 cm–1 in the IR spectrum, which is close to those of the
reported (sulfenato)PtII complexes.[12–24] Recrystallization
of 18 from benzene provided single crystals (yellow prisms)
suitable for X-ray crystal analysis, and the structure was
determined unambiguously (Figure 2).
Figure 1. ORTEP drawing of 3,3-di-tert-butyldithiirane trans-1,2-
dioxide (8) with 30% probability thermal ellipsoids. Relevant bond
lengths [Å] and angles [°]: S1–O1 1.467(2), S1–C1 1.854(2), S1–S1*
2.2308(11), C1–C2 1.561(2), C1–S1 1.854(2), O1–S1–C1
115.79(10), O1–S1–S1* 113.48(9), C2–C1–C2* 122.7(2), C2–C1–
S1* 110.44(10), C2–C1–S1 114.63(10), S1–C1–S1* 73.98(10).
formation mechanism of 15–17. No formation of 15 and 17
on the decomposition in chloroform at room temperature
may indicate that the 1,2-oxygen shift of 8 to the dithiirane
1,1-dioxide requires a larger activation energy than the ex-
trusion of SO to give 16, which is consistent with the theo-
retical consideration.[9]
Figure 2. ORTEP drawing of (disulfenato)PtII complex 18 with
30% probability thermal ellipsoids. Hydrogen atoms and the sol-
vated molecules (C6H6) were omitted for clarity.
The (sulfenato–thiolato)PtII complex 14 was prepared by
the treatment of dithiirane 1-oxide 15 with [(Ph3P)2Pt(η2-
C2H4)] conducted in dichloromethane at –20 °C [Equa-
tion (7)]. The structure was determined by X-ray crystal-
lography as depicted in Figure 3.
Platinum Complexes
1,2-Dioxide 8 was treated with [(Ph3P)2Pt(η2-C2H4)] in
dichloromethane at 0 °C. The mixture containing the de-
sired (disulfenato)PtII complex 18, sulfine 16, and 8 was
recrystallized from a mixed solvent of hexane and dichloro-
methane at –20 °C to give 18 as a yellow powder in 56%
yield [Equation (6)]. The structure of 18 was supported by
Oxidation of the sulfenato–thiolato complex 14 was in-
the following spectroscopic data. In the 1H NMR spectrum, vestigated [Equation (8)] (Table 1). Oxidation with an equi-
the two tert-butyl groups are equivalent (δ = 1.41 ppm), in- molar amount of DMD in toluene at 0 °C yielded the (sul-
dicating that the configuration of the two S=O groups in finato–thiolato)PtII complex 19 as the main product together
18 is not cis but trans. In the 31P NMR spectrum a singlet with the starting complex 14, sulfine 16, and [Pt(PPh3)2-
accompanying the satellite signals (1JPt,P = 2596 Hz) from (S2O2)][20,42] (Table 1, Entry 1). The (disulfenato)PtII com-
1
the 195Pt isotope is observed at δ = 15.2 ppm. This JPt,P plex 18 was not formed at all. The structure of 19 was deter-
Eur. J. Inorg. Chem. 2007, 5199–5206
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A. Ishii, M. Ohishi, N. Nakata
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Figure 4. ORTEP drawing of (sulfinato–thiolato)PtII complex 19
with 30% probability thermal ellipsoids. Hydrogen atoms and sol-
vated molecules (CH2Cl2) are omitted for clarity.
Figure 3. Molecular structure of the (sulfenato–thiolato)PtII com-
plex 14 with 30% probability thermal ellipsoids. Hydrogen atoms
and solvated molecules (CH2Cl2) are omitted for clarity.
mined from spectroscopic data. In the 31P NMR spectrum,
two doublets accompanying satellite signals from the 195Pt
was employed as the oxidant both 18 and 19 were formed
albeit in low yields (18/19/14/Ph3P=O ≈ 6:9:29:56) (Entry
3). The oxidation of 14 with DMD in the presence of
CF3CO2H yielded 18 together with 14 and 16 (18/14/16 ≈
30:28:42) (Entry 4), and that in the presence of benzoic acid
gave 19 (19/Ph3P=O ≈ 81:16) (Entry 5). The change in re-
gioselectivity as described above was explained by proton-
ation on the sulfinyl oxygen atom with the coexisting car-
boxylic acid leading to a decrease in the electron density on
the sulfinyl-sulfur atom [Equation (9)]. The extent of the
decrease in the electron density is dependent on the strength
of the acid.
2
1
isotope are observed at δ = 11.6 (d, JP,P = 18.6 Hz, JPt,P
2
1
= 2310 Hz) and 18.7 (d, JP,P = 18.6 Hz, JPt,P = 3053 Hz).
In the infrared spectrum stretching vibrations from the SO2
group appear at 1067 and 1197 cm–1. The structure of 19
was finally determined by X-ray crystallography (Figure 4).
Table 1. Oxidation of (sulfenato–thiolato)PtII complex 14.
Entry [O]
18
19
14[a] Others
1
2
3
4
5
DMD
0[b]
9[b]
6[c]
62[b] 32[b] 16 {6[b], [Pt(PPh3)2(S2O2)]}
CF3CO3H
MCPBA
0[b]
9[c]
73[b] 16 (18[b]
29[c] Ph3P=O (56[c])
28[b] 16 (42[b]
Ph3P=O (16[b]
)
)
Oxidation of (sulfenato–thiolato)PtII complex 14 with an
excess amount of DMD (5 molar equiv.) provided the (di-
sulfonato)PtII complex 20 quantitatively [Equation (10)],
the structure of which was determined by X-ray crystal-
lography (Figure 5). The PtO2S2C six-membered ring has a
DMD/CF3CO2H 30[b] 0[b]
)
DMD/PhCO2H
0
84[c]
0
[a] Recovery. [b] H NMR integral ratio. [c] 31P NMR peak height
ratio.
1
Thus, it was verified that the oxidation of the (sulfenato– twist conformation in the crystalline state. While the two
thiolato)PtII complex 14 with DMD took place in the same tert-butyl groups are equivalent in the 13C NMR spectrum,
1
regioselectivity as observed in the oxidation of 11 with they are nonequivalent in the H NMR spectrum. In the
DMD to give 12 [Equation (3)].
31P NMR spectrum, a singlet with satellite signals from the
On the other hand, oxidation of 14 with CF3CO3H gave 195Pt isotope is observed at δ = 7.10 ppm (1JPt–P
=
the (disulfenato)PtII complex 18 without 19 though this re- 4157 Hz). Formation of a similar sulfonato complex was
action was sluggish (a large portion of the starting complex reported from the oxidation of the (dithiolato)NiII complex
14 was recovered) and a substantial amount of sulfine 16 with hydrogen peroxide [Equation (11)].[43] 31P NMR spec-
was formed as a decomposition product (1H NMR integral troscopic data of PtII complexes 14, 18–20 are summarized
ratio: 18/14/16 ≈ 9:73:18) (Table 1, Entry 2). When MCPBA in Table 2.
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(Disulfenato)PtII Complex
X-ray Crystallography of Platinum(II) Complexes 14 and
18–20
The selected bond lengths and angles of 14, 18, and 19
are summarized in Table 3. The sum of the four angles
around the Pt atom in 14 and 18–20 is almost 360° and the
platinum atoms keep the planarity in these complexes. The
puckered angles of the four-membered rings of 18, 14, and
19 are 3.6°, 25.2°, and 13.0°, respectively. The S1–Pt1 and
S2–Pt1 bond lengths in 18, 14, and 19 are not significantly
influenced by the oxidation state of the sulfur atoms and
lie in the narrow range 2.3065(14)–2.3421(6) Å. The P1–Pt1
and P2–Pt1 bond lengths in 18, 14, and 19 also fall into a
narrow range [2.2943(14)–2.3347(19) Å], though the P1–Pt1
bonds trans to the thiolato ligands in 14 [2.2943(14) Å] and
19 [2.2956(15) Å] are slightly shorter than the others be-
cause of the weaker trans influence of the thiolato ligands
compared with those of the sulfenato and sulfinato ligands.
The P1–Pt1 [2.2224(9) Å] and P2–Pt1 [2.2375(9) Å] bond
lengths in the disulfonato complex 20, which are trans to
the O atoms of the sulfonato ligands, are obviously shorter
than the above Pt–P bond lengths.
Table 3. Selected bond lengths [Å] and bond angles [°] of 18, 14,
and 19.
Figure 5. ORTEP drawing of (disulfonato)PtII complex 20 with
30% probability thermal ellipsoids. Relevant bond lengths [Å] and
angles [°]: Pt1–O1 2.090(2), Pt1–O6 2.107(2), Pt1–P1 2.2224(9),
Pt1–P2 2.2375(9), O1–S1 1.503(2), S1–O2 1.438(3), S1–O3 1.442(3),
S1–C1 1.877(3), C1–C6 1.617(5), C1–C2 1.623(5), C1–S2 1.888(3),
S2–O4 1.436(3), S2–O5 1.439(3), S2–O6 1.512(2), O1–Pt1–O6
85.47(9), O1–Pt1–P1 88.60(7), O6–Pt1–P1 173.97(6), O1–Pt1–P2
173.25(7), O6–Pt1–P2 87.92(6), P1–Pt1–P2 98.04(3), S1–O1–Pt1
115.52(13), O2–S1–O3 115.09(15), O2–S1–O1 109.79(14), O3–S1–
O1 110.15(14), O2–S1–C1 106.74(15), O3–S1–C1 109.95(15), O1–
S1–C1 104.55(14), C6–C1–C2 117.8(3), C6–C1–S1 108.3(2), C2–
C1–S1 109.0(2), C6–C1–S2 109.0(2), C2–C1–S2 107.3(2), S1–C1–
S2 104.76(16), O4–S2–O5 115.17(16), O4–S2–O6 110.18(14), O5–
S2–O6 109.26(14), O4–S2–C1 109.91(16), O5–S2–C1 106.42(15),
O6–S2–C1 105.39(14), S2–O6–Pt1 116.00(13).
18
14
19
S1
S2
S1=SO
S2=SO
S1=SO
S2=S
S1=SO2
S2=S
S1–Pt1
S2–Pt1
P1–Pt1
(trans to S2–Pt1)
P2–Pt1
2.3134(10)
2.3251(10)
2.3090(10)
2.3421(6)
2.3065(14)
2.2943(14)
2.3221(16)
2.3163(15)
2.2956(15)
2.3347(10)
2.3130(15)
2.3012(14)
(trans to S1–Pt1)
S1–O1, S1–O2
1.511(3)
1.506(5)
1.434(16)
1.464(5)
–
1.936(6)
1.891(6)
1.571(9)
1.607(9)
S2–O2
S1–C1
S2–C1
C1–C2
C1–C6
1.509(3)
1.917(3)
1.899(4)
1.577(5)
1.588(5)
–
1.902(6)
1.860(7)
1.586(8)
1.591(8)
S1–Pt1–P1
P1–Pt1–P2
P2–Pt1–S2
S2–Pt1–S1
93.43(4)
99.00(4)
91.15(4)
76.39(3)
(359.97)[a]
167.50(4)
165.48(3)
92.38(12)
97.79(18)
92.74(12)
120.5(3)
(3.6)[b]
93.53(5)
99.30(5)
94.02(5)
72.94(5)
(359.79)[a]
166.78(5)
165.89(6)
92.2(2)
95.79(6)
97.60(5)
93.93(5)
72.66(6)
(359.98)[a]
166.60(6)
167.92(5)
94.66(19)
91.8(3)
S1–Pt1–P2
S2–Pt1–P1
Pt1–S1–C1
S1–C1–S2
C1–S2–Pt1
C2–C1–C6
94.5(3)
94.40(18)
118.5(5)
(25.2)[b]
96.08(19)
118.4(5)
(13.0)[b]
Table 2. 31P NMR spectroscopic data of PtII complexes 14 and 18–
20.
[a] Sum of the above four angles around the Pt atom. [b] Puckered
angle of the four-membered ring.
Compound
δ [ppm]
2J(31P,31P) [Hz]
1J(195Pt,31P) [Hz]
18
14
15.2
16.8
17.9
11.6
18.7
7.10
–
2596
3306
2338
2310
3053
4157
24.4
24.4
18.6
18.6
–
The S=O bond lengths of the SO2 group in 19 and 20
[1.434(16)–1.464(5) Å] are shorter than those of the sulfen-
ato ligands in 18 [1.509(3) and 1.511(3) Å] and 14
[1.506(5) Å]. This is in accordance with those for dialkyl
19
20
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A. Ishii, M. Ohishi, N. Nakata
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sulfones [R–S(O)2–RЈ, S–O 1.436 Å[44]] and sulfoxides
butyl thioketone S-oxide (16) in the ratio 89:1:10. The residue was
recrystallized from a mixed solvent of hexane and dichloromethane
at –20 °C to give 39.9 mg (79%) of 1,2-dioxide 8 as pale-yellow
plates. M.p. 85 °C (decomp.). 1H NMR: δ = 1.38 (s, 18 H) ppm.
[R–S(O)–RЈ, S–O 1.497 Å[44]] (R, RЈ = alkyl).
The S1–C1 bond [S(O)2–C bond] in 19 is elongated to a
length of 1.936(6) Å, which is much longer than those of a
similar type in 20 [S1–C1 1.877(3) Å and S2–C1
1.888(3) Å]. This elongation in 19 is explained by a large
steric repulsion between the two oxygen atoms and the two
tert-butyl groups as well as the PPh3 ligand at the cis posi-
tion in the four-membered ring. While ordinary S–C bond
lengths in organic sulfides, sulfoxides, and sulfones become
shorter in this order (1.819, 1.809, and 1.779 Å, respec-
tively[44]), this is not true for the present, sterically con-
gested system.
13C NMR: δ = 31.1 (CH ), 41.6 (C), 105.9 (C) ppm. IR (KBr): ν
˜
3
= 1063 cm–1. C9H18O2S2 (222.36): calcd. C 48.61, H 8.16; found C
48.87, H 8.22.
[2,2,4,4-Tetramethylpentane-3,3-dithiolato(2–)-κS,κSЈ]bis(triphenyl-
phosphane)platinum trans-S,SЈ-Dioxide [(Disulfenato)PtII Complex
18]: A solution of [(Ph3P)2Pt(η2-C2H4)] (92.9 mg, 0.124 mmol) in
dichloromethane (2 mL) was added to a solution of 1,2-dioxide 8
(27.8 mg, 0.125 mmol) in dichloromethane (5 mL) cooled to 0 °C
under argon. The mixture was stirred for 2 h at 0 °C, and the sol-
vent was removed under reduced pressure. The residue was recrys-
tallized twice from a mixed solvent of hexane and dichloromethane
at –20 °C to give 66.3 mg (56%) of the (disulfenato)PtII complex
18. M.p. 125 °C (decomp.). 1H NMR: δ = 1.41 (s, 18 H), 7.18–7.22
(m, 12 H), 7.29–7.34 (m, 6 H), 7.38–7.43 (m, 12 H) ppm. 13C NMR:
δ = 31.22 (CH3), 43.97 (C), 128.08 (t, JP,C = 5.3 Hz, CH), 130.20
(dd, JP,C = 57.2, 7.4 Hz, C), 130.27 (CH), 134.21 (t, JP,C = 5.6 Hz,
Conclusions
We prepared a three-membered vic-disulfoxide, 3,3-di-
tert-butyldithiirane trans-1,2-dioxide (8). Complexation of
8 with a platinum(0) complex yielded the (disulfenato)PtII
complex 18 in high yield by oxidative addition. This is the
only direct method for the synthesis of (disulfenato)PtII
complexes. We showed that oxidation positions of (sulfen-
ato–thiolato)PtII complexes, sulfenato sulfur or thiolato sul-
fur, can be controlled by the acidity of the reaction media.
1
CH) ppm. 31P NMR: δ = 15.2 (s, JPt,P = 2596 Hz for the satellite
signals) ppm. IR (KBr): ν = 1097 cm–1. C45.5H49ClO2P2PtS2
˜
(C45H48O2P2PtS2·0.5CH2Cl2) (984.49): calcd. C 55.51, H 5.02;
found C 56.17, H 5.03 (the 1H NMR spectrum of the same sample
subjected to the elemental analysis showed the presence of 0.50
molecules of CH2Cl2 and a molecule of 18). Single crystals suitable
for X-ray crystallography were obtained by recrystallization from
benzene at room temperature.
[2,2,4,4-Tetramethylpentane-3,3-dithiolato(2–)-κS,κSЈ]bis(triphenyl-
phosphane)platinum S-Oxide [(Sulfenato–thiolato)PtII Complex 14]:
A solution of [(Ph3P)2Pt(η2-C2H4)] (202.1 mg, 0.218 mmol) in
dichloromethane (8 mL) was added to a solution of dithiirane 1-
oxide 15 (45.0 mg, 0.218 mmol) in dichloromethane (3 mL) cooled
to 0 °C under argon. The mixture was stirred for 2 h at 0 °C, and
the solvent was removed under reduced pressure. The residue was
recrystallized from a mixed solvent of hexane and dichloromethane
at –20 °C to give 152.5 mg (76%) of the (sulfenato–thiolato)PtII
Experimental Section
The melting points were determined with a Mel-Temp capillary
tube apparatus and are uncorrected. 1H, 13C, and 31P NMR spectra
were determined with Bruker AM400 or DRX400 (400, 100.7, and
162 MHz, respectively) spectrometers using CDCl3 as the solvent
at 25 °C, unless otherwise noted. IR spectra were recorded with a
Perkin–Elmer System 2000 FT-IR spectrometer. Elemental analy-
ses were performed by the Molecular Analysis and Life Science
Center of Saitama University, where those for platinum complexes
were performed with WO3 as the combustion improver. An acetone
solution of dimethyldioxirane (DMD) was prepared by oxidation
of acetone with Oxone® (Sigma–Aldrich).[45]
1
complex 14 as yellow prisms. M.p. 207 °C (decomp.). H NMR: δ
= 1.12 (s, 9 H), 1.45 (br. s, 6 H), 1.62 (s, 3 H), 7.14–7.20 (m, 12 H),
7.24–7.30 (m, 6 H), 7.38–7.45 (m, 12 H) ppm. 13C NMR: δ = 29.30
(CH3), 32.98 (br. s, CH3), 42.60 (C), 46.30 (C), 127. 72 (t, JP,C
=
9.9 Hz, CH), 130.01 (CH), 134.3 (m, CH) ppm (signals for aromatic
3,3-Di-tert-butyldithiirane 1-Oxide (15): A solution of di-tert-butyl-
diazomethane (727.9 mg, 4.719 mmol) in dichloromethane (20 mL)
was added to a solution of S8O (1.548 g, 5.691 mmol) in dichloro-
methane (250 mL) cooled to 0 °C. The mixture was stirred for 1 h
at 0 °C and for 2 h at room temperature. Precipitates were filtered
and washed with dichloromethane, and the filtrate and the wash-
ings were combined. The solvent was removed under reduced pres-
sure, and the residue was subjected to column chromatography (sil-
ica gel: hexane/dichloromethane, 1:2) and then HPLC (hexane/
dichloromethane, 3:2) to give dithiirane 1-oxide 15 as a pale-yellow
oil (116.8 mg, 12%): 1H NMR: δ = 1.08 (s, 9 H), 1.42 (s, 9 H) ppm.
13C NMR: δ = 29.2 (CH3), 31.9 (CH3), 41.2 (C), 41.3 (C), 86.3
quaternary carbons appear at δ = 130.425, 130.794, 130.892, and
2
131.297 ppm, which are not assigned). 31P NMR: δ = 16.8 (d, JP,P
1
= 24.4 Hz and JPt,P = 3306 Hz for the satellite signals), 17.9 (d,
1
2JP,P = 24.4 Hz and JPt,P = 2338 Hz for the satellite signals) ppm.
C47H52Cl4OP2PtS2 (C45H48OP2PtS2·2CH2Cl2) (1095.89): calcd. C
51.51, H 4.78; found C 51.24, H 4.66.
[2,2,4,4-Tetramethylpentane-3,3-dithiolato(2–)-κS,κSЈ]bis(triphenyl-
phosphane)platinum S,S-Dioxide [(Sulfinato–thiolato)PtII Complex
19]: A solution of DMD (0.085 , 0.34 mL, 0.029 mmol) was added
to a solution of the (sulfenato–thiolato)PtII complex 14 (27.1 mg,
0.0292 mmol) in toluene (3 mL) cooled to 0 °C under argon. The
mixture was stirred for 2 h at 0 °C, and the solvent was removed
under reduced pressure at 0 °C. The 1H NMR spectrum of the
residue (28.7 mg) indicated the presence of 19, 14, and sulfine 16
in the ratio 62:32:6, while the 31P NMR spectrum showed signals
from 19 (δ = 11.6 and 18.7 ppm) and 14 (δ = 16.8 and 18.9 ppm)
together with a small amount of [Pt(PPh3)2(S2O2)] (δ = 6.3 ppm).
The residue was recrystallized from a mixed solvent of hexane and
dichloromethane at –20 °C to give 5.1 mg of an ca. 2:1 mixture of
19 and 14. As we could not obtain 19 in the pure form, even by
(C) ppm. IR (neat): ν = 1121 cm–1. C H OS (206.36): calcd. C
˜
9
18
2
52.38, H 8.79; found C 52.63, H 8.82.
3,3-Di-tert-butyldithiirane trans-1,2-Dioxide (8): DMD (0.079 ,
17.0 mL, 1.343 mmol) was added to a solution of 3,3-di-tert-butyl-
dithiirane 1-oxide (15) (46.8 mg, 0.227 mmol) in dichloromethane
(1.5 mL) cooled to –20 °C under argon. The mixture was stirred at
–20 °C for 2 h, and the solvent was removed under reduced pres-
sure at 0 °C. The 1H NMR spectrum of the residue showed the
formation of 1,2-dioxide 8, di-tert-butyl ketone (17), and di-tert-
5204
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© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 5199–5206

(Disulfenato)PtII Complex
¯
repeated recrystallization, elemental analysis of 19 was not done.
However, a single, yellow crystal suitable for X-ray analysis was
obtained. 1H NMR: δ = 1.50 (br. s, 18 H), 7.14–7.21 (m, 12 H),
0.10 mm, triclinic, P1, a = 11.6339(6), b = 14.6630(7), c =
15.1190(8) Å, α = 113.4220(10), β = 94.0080(10), γ = 93.0900(10)°,
V = 2351.4(2) Å3, ρcalcd. = 1.570 gcm–3, Z = 2, µ(Mo-Kα) =
7.28–7.32 (m, 6 H), 7.38–7.44 (m, 6 H), 7.50–7.55 (m, 6 H) ppm. 3.405 cm–1. Intensity data of 8731 unique reflections were collected
31P NMR: δ = 11.6 (d, 2JP,P = 18.6, 1JPt,P = 2310 Hz), 18.7 (d, 2JP,P
over the range –12 Յ h Յ 14, –17 Յ k Յ 16, –13 Յ l Յ 18 at 153 K.
= 18.6, JPt,P = 3053 Hz) ppm. IR (KBr): ν = 1067, 1197 R1 = 0.0438 [I Ն 2σ(I), 7944 reflections], wR2 = 0.1144 (for all), and
1
˜
(SO2) cm–1.
Gof = 1.037, 523 parameters; max./min. residual electron density:
2.599/–1.047 eÅ–3.
[2,2,4,4-Tetramethylpentane-3,3-disulfonato(2–)-κO,κOЈ]bis(triphen-
ylphosphane)platinum [(Disulfonato)PtII Complex 20]: DMD
(0.083 , 1.25 mL, 0.10 mmol) was added dropwise to a solution
of the (sulfenato–thiolato)PtII complex 14 (19.3 mg, 0.021 mmol)
in toluene (7 mL) at 0 °C under argon. The mixture was stirred for
2 h at 0 °C, and the solvent was removed under reduced pressure
at 0 °C to give an almost pure 20 as a yellow-white solid (20.9 mg).
The crude material was recrystallized from a mixed solvent of hex-
ane and dichloromethane at –20 °C to give 7.1 mg (34%) of 20 as
Crystal Data for 20: C47H52Cl4O6P2PtS2 (C45H48O6P2PtS2·
2CH2Cl2), Mr = 1175.84 gmol–1, colorless prism, crystal size =
0.30ϫ0.22ϫ0.20 mm, monoclinic, P21/c, a = 11.9094(5), b =
24.2783(11), c = 16.9933(7) Å, β = 98.3500(10)°, V = 4861.4(4) Å3,
ρcalcd. = 1.607 gcm–3, Z = 4, µ(Mo-Kα) = 3.305 cm–1. Intensity data
of 9053 unique reflections were collected over the range –14 Յ h
Յ 14, –28 Յ k Յ 29, –20 Յ l Յ 17 at 123 K. R1 = 0.0294 (I Ն
2σ(I), 8018 reflections), wR2 = 0.0716 (for all), and Gof = 1.047,
565 parameters; max./min. residual electron density: 1.444/–
0.844 eÅ–3.
1
colorless prisms. M.p. 280 °C (decomp.). H NMR: δ = 1.52 (br. s,
9 H), 1.58 (s, 9 H), 7.20–7.26 (m, 12 H), 7.36–7.40 (m, 6 H), 7.53–
7.59 (m, 12 H) ppm. 13C NMR: δ = 32.91 (CH3), 42.32 (C), 126.10
CCDC-655818 (for 8), -655819 (for 18), -655820 (for 14), -655821
(for 19), and -655822 (for 20) contain the supplementary crystallo-
graphic data. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
(d, JP,C = 68.3 Hz, C), 128.47 (t, JP,C = 5.9 Hz, CH), 131.60 (CH),
1
134.58 (t, JP,C = 5.4 Hz, CH3) ppm. 31P NMR: δ = 7.10 (s, JPt,P
=
.
4 157 Hz ) ppm. I R ( KB r) : ν = 11 39 , 1 28 4 ( SO ) cm– 1
˜
2
C45H48O6P2PtS2 (1006.02): calcd. C 53.73, H 4.81; found C 54.01,
H 5.04.
Supporting Information (see also the footnote on the first page of
this article): 13C NMR spectra of 14, 18, and 20, and H and 31P
1
X-ray Crystallography: X-ray crystallographic analyses were per-
formed with a Mac Science DIP3000 diffractometer (for 14) or a
Bruker AXS SMART diffractometer (for others) with a graphite-
monochromated Mo-Kα radiation (λ = 0.71073 Å). The structures
were solved by direct methods and refined with full-matrix least-
squares (SHELXL-97[46]) using all independent reflections.
NMR spectra of 19 as a mixture with 14.
Acknowledgments
This work was supported by the Innovative Research Organization,
Saitama University (A05-23 and A06-616).
Crystal Data for 8: C9H18O2S2, Mr = 222.35 gmol–1, yellow prism,
crystal size
14.9253(13), b = 7.0524(6), c = 11.4484(9) Å, β = 105.485(2)°, V =
1161.31(17) Å3, ρcalcd. 1.272 gcm–3,
4, µ(Mo-Kα)
= 0.40ϫ0.40ϫ0.40 mm, monoclinic, C2/c, a =
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¯
17.7604(13) Å, α = 81.859(2), β = 88.115(2), γ = 82.946(2)°, V =
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www.eurjic.org
5205

A. Ishii, M. Ohishi, N. Nakata
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