Stereoselective thiirane desulfurization controlled by a bridging or terminal acyl ligand: Concerted vs. SN2 pathways

Article abstract of DOI:10.1016/j.jorganchem.2013.04.003

An acyl-bridged heterodinuclear Pt/Mn complex [(dppe)Pt(μ-C(O)Np- 1κC,2κO)-Mn(CO)₄] (Np = neopentyl, -CH ₂CMe₃) has been prepared and unambiguously characterized. Upon reaction with thiiranes, this species is able to facilitate the direct desulfurization of three-membered S-heterocycles to produce olefins with complete retention of stereochemistry, with kinetic details supporting a concerted mechanism for thiirane desulfurization. Conversion of this species to a non-bridged, opened Pt/Mn complex [(dppe)(NpC(O))Pt-Mn(CO)₅] can be effected by reaction with CO_(g) in benzene solution. These non-bridged species display the opposite reactivity with thiiranes, generating the isomer with an inverted stereochemistry. Isolation of key thiamanganacyclic intermediates indicate that inversion occurs in the first C-S bond cleavage event, while the second desulfurization step proceeds with retention to produce the olefin. As a result, control of stereoselectivity in this process appears to be mediated by the existence or absence of forced Pt/Mn metal-metal proximity.

Full text of DOI:10.1016/j.jorganchem.2013.04.003

Journal of Organometallic Chemistry 739 (2013) 6e10
Contents lists available at SciVerse ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Communication
Stereoselective thiirane desulfurization controlled by a bridging or
terminal acyl ligand: Concerted vs. SN2 pathways
*
Matthew T. Zamora, Kenta Oda, Nobuyuki Komine, Masafumi Hirano, Sanshiro Komiya
Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei,
Tokyo 184-8588, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
An acyl-bridged heterodinuclear Pt/Mn complex [(dppe)Pt(
m
-C(O)Np-1
k
C,2
k
O)eMn(CO)4] (Np ¼ neopentyl,
Received 2 February 2013
Received in revised form
7 March 2013
eCH2CMe3) has been prepared and unambiguously characterized. Upon reaction with thiiranes, this species
is able to facilitate the direct desulfurization of three-membered S-heterocycles to produce olefins with
complete retention of stereochemistry, with kinetic details supporting a concerted mechanism for thiirane
desulfurization. Conversion of this species to a non-bridged, opened Pt/Mn complex [(dppe)(NpC(O))Pt
eMn(CO)5] can be effected by reaction with CO(g) in benzene solution. These non-bridged species display
the opposite reactivity with thiiranes, generating the isomer with an inverted stereochemistry. Isolation of
key thiamanganacyclic intermediates indicate that inversion occurs in the first CeS bond cleavage event,
while the second desulfurization step proceeds with retention to produce the olefin. As a result, control of
stereoselectivity in this process appears to be mediated by the existence or absence of forced Pt/Mn metal
emetal proximity.
Accepted 3 April 2013
Keywords:
CeS cleavage
Dinuclear cooperativity
Thiirane
Desulfurization
Stereoselective
Ó 2013 Elsevier B.V. All rights reserved.
1. Introduction
We previously reported the synthesis of a series of hetero-
dinuclear organoplatinumemanganese complexes having both
Cooperativity of transition metals in catalysis is one of the most
intriguing and unsolved phenomena at the molecular level.
Although many transition-metal-mediated processes utilize
monometallic catalysts, many successful variants employ the use of
two metals instead of one to exploit aspects of “metalemetal
cooperativity”, such as, for example, in the catalytic desulfurization
of oil using Co/Mo [1,2] and Ni/Mo systems [3]. Unfortunately
however, the origin of these cooperative effects is far from being
understood, although there have been significant recent advances
[4e13]. In our group, reactions involving heterocyclic ring-opening
processes are of significant interest since they provide invaluable
routes to many important organic compounds [14e17]. In partic-
ular, the cleavage of carbonesulfur bonds in S-heterocycles attracts
considerable attention in transition-metal catalysis [18], owing to
the ubiquitous nature of this process in the study of materials and
pharmacological products [19]. To this effect, molecular dinuclear
complexes may offer a unique opportunity to model many of these
CeS bond cleavage processes.
PteMn and MeC bonds [(dppe)RPteM(CO)5] (dppe
¼
1,2-
bis(diphenylphosphino)ethane, R ¼ Me, Et; M ¼ Mn, Re) by
metathesis of [(dppe)PtRX] with Na[M(CO)5]. Upon reaction with
cis- and trans-2,3-dimethylthiirane, these complexes cleanly pro-
moted CeS bond cleavage with inversion of stereochemistry to
give the corresponding (thiametallacycle)platinum complexes,
which upon heating resulted in desulfurization to produce the
respective trans- and cis-2-butenes (Scheme 1) [20]. During our
continuous studies, we serendipitously discovered an unexpected
structural feature when this system contains a neopentyl group
(R ¼ Np, eCH2CMe3) where an acyl moiety is formed and subse-
quently acts as a bridging ligand between the PteM linkage. In this
communication, we wish to report the unique aspects of the new
PteMn heterodinuclear complex, where this ancillary bridging
ligand forces complete retention of configuration in CeS bond
cleavage of thiiranes caused by cooperativity of the Pt and Mn
metals, while related dinuclear complexes without this bridging
ligand show inversion of configuration in these reactions.
* Corresponding author. Present address: Department of Chemistry, Gakushuin
University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan. Tel./fax: þ81
339860221.
E-mail addresses: matt@cc.tuat.ac.jp (M.T. Zamora), 50011642110@st.tuat.ac.jp
(K. Oda), komine@cc.tuat.ac.jp (N. Komine), hrc@cc.tuat.ac.jp (M. Hirano),
komiya@cc.tuat.ac.jp, sanshiro.komiya@gakushuin.ac.jp (S. Komiya).
2. Results and discussion
Using methods and conditions similar to those used to generate
the non-bridged methyl and ethyl complexes [20], the new acyl-
bridged Pt/Mn complex [(dppe)Pt(m-C(O)Np-1kC,2kO)eMn(CO)4]
0022-328X/$ e see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2013.04.003

M.T. Zamora et al. / Journal of Organometallic Chemistry 739 (2013) 6e10
7
Δ
Scheme 1. Reaction of Pt/Mn species with substituted thiirane to produce alkene with inversion of stereochemistry.
(2) was prepared in 82% yield from the mononuclear Pt species 1
(Scheme 2). The isolation of single crystals of 2 allowed us to
deduce a bridging geometry as shown in Fig.1. In the generation of 2
from 1, the neopentyl group is considered to migrate from platinum
to the manganese atom upon generation of the PteMn bond, most
likely due to steric congestion at Pt caused between the proximal
Ph groups of the dppe ligand and the bulky neopentyl group itself.
Along with electronic factors associated with the neopentyl group
being strongly electron-donating, facile CO insertion can generate a
less bulky acyl group eC(O)Np, which can subsequently migrate
back to Pt and coordinate to Mn via the carbonyl oxygen atom to
occupy its vacant site, inherently locking it into close proximity.
Such a unique and facile insertion process, including organic
group transfer along PteM bonds, has been proposed by us previ-
ously [21].
species was found to be the thiocarboxylato species 3, as confirmed
by X-ray structure analysis as shown in Fig. 2.
In this structure, the Pt and Mn atoms reside in extremely
strained square planar and octahedral geometries, respectively, as
The acyl group on platinum forms a bridge between the two
ꢀ
metals, locking them into close proximity (PteMn ¼ 2.607(1) A),
especially when compared to non-bridged cases such as in [(dppe)
ꢀ
MePteMn(CO)5] (2.795(2) A) [20]. The oxygen atom from the acyl
group is firmly bound to Mn, forming a planar four-membered
ꢀ
metallacycle (MneO(1) ¼ 2.070(6) A), since the sum of the in-
ternal angles about PteC(36)eO(1)eC(1) is 360ꢀ. Spectroscopi-
cally, the resonance representing the phosphorus trans to the
manganese atom exhibits much weaker coupling to 195Pt (1JPe
¼ 2230 Hz) compared to the aforementioned methyl and ethyl
Pt
systems (1JPePt ¼ 3267 Hz) [20], which suggests that the trans
influence of the manganese group is clearly weakened by this
“locked” geometry.
Fig. 1. Three-dimensional representation of bridged species [(dppe)Pt(
m-C(O)Np-
1k
C,2kO)eMn(CO)4] (2) showing the numbering scheme. Thermal ellipsoids are shown
at the 50% probability level, except for hydrogen atoms, which are placed at the
calculated positions based on the riding model. Hydrogen atoms on the dppe and
methyl groups are not shown. Only the ipso carbons of the dppe phenyl rings are
As shown in Scheme 3, the bridged species 2 reacts with trans-
and cis-2,3-dimethylthiirane at 50 ꢀC in a different way than the
terminal methyl and ethyl variants, releasing trans- and cis-2-
butene in 90% and 89% yield, respectively. This direct desulfuriza-
tion of thiiranes does not display any appreciable solvent effect,
advancing at identical rates in both benzene and acetone.
Furthermore, when desulfurization was attempted with a variety of
other thiiranes, namely 2-methylthiirane, thiirane, 7-thiabicyclo
[4.1.0]heptane, and 2,2-dimethylthiirane, the rate of conversion
did not change significantly, even when much more bulky thiiranes
were used (see Supplementary data). The resulting organometallic
ꢀ
shown. Relevant parameters (distances in A and angles in deg.): PteMn ¼ 2.607(1),
PteP(1) ¼ 2.284(2), PteP(2) ¼ 2.319(2), PteC(1) ¼ 2.022(8), MneO(1) ¼ 2.070(6),
C(1)eO(1) ¼ 1.261(9); P(1)ePteMn ¼ 169.97(5), P(2)ePteC(1) ¼ 173.9(3), PteMne
C(34) ¼ 167.3(3), O(1)eMneC(35) ¼ 176.1(3), MnePteC(1)eO(1) ¼ ꢁ0.3(5)
Δ
Δ
Scheme 2. Synthesis of bridged species 2.
Scheme 3. Desulfurization of thiiranes using bridged (2) or non-bridged (4) species.

8
M.T. Zamora et al. / Journal of Organometallic Chemistry 739 (2013) 6e10
acyl oxygen on Mn by CO, generating an opened acyl product
[(dppe)(NpC(O))PteMn(CO)5] (4), analogous to the non-bridged
methyl and ethyl species noted previously. However, unless the
solution of 4 is kept under CO atmosphere, it begins to convert
back to 2 in less than 1 h. This reversibility indicates that these
two species are in equilibrium in the presence of CO(g)
.
With this new acyl non-bridged species in hand, we tested
whether complex 4 would also facilitate the desulfurization of
thiiranes with inversion of stereochemistry, despite the electronic
differences imparted by the acyl group compared to non-bridged
methyl and ethyl variants. As expected, on treatment with cis-
and trans-2,3-dimethylthiirane at room temperature, complex 4
produces the anti- and syn-thiamanganacyclic complexes 5,
respectively, analogous to the methyl and ethyl systems [20]
(Scheme 3). This in turn helps support our hypothesis of the
bridged vs. non-bridged dichotomy dictating stereochemistry of
the released olefin. Furthermore, although reaction of the bridged
species 2 with thiiranes did exhibit signs of an appreciable solvent
effect, the rate of the reaction of 4 is clearly accelerated by polar
solvents, which is consistent with an SN2 process for this initial CeS
bond cleavage event of desulfurization by non-bridged dinuclear
Pt/Mn complexes. This process most likely proceeds via a cationic
intermediate after dissociation of the Mn(CO)ꢁ5 moiety, followed by
coordination of thiirane to Pt as previously noted. An X-ray
diffraction study of 5anti unequivocally confirms our structural
hypothesis (Fig. 3).
Heating of these syn- and anti-thiamanganacyclic species at
75 ꢀC results in the liberation of cis- and trans-2-butene, respec-
tively, in quantitative yields. Interestingly, the fate of the organo-
metallic complex is identical to that from the bridged species 2
(Scheme 3), as made evident by identical spectral parameters.
However, 2 obviously transforms into 3 via a very different mech-
anism (vide infra). Although transformation of 4 to 5 proceeded
with inversion, this second step appears to continue with complete
retention of stereochemistry and indicates no solvent effect.
Furthermore, analysis of the headspace at the conclusion of this
reaction confirmed the stoichiometric release of CO(g), as detected
by GC.
Fig. 2. Three-dimensional representation of thiocarboxylato-bridged platinum/man-
ganese species [(dppe)Pt(m-SC(O)Np)eMn(CO)4] (3) showing the numbering scheme.
Thermal ellipsoids are as described as in Fig. 1. Hydrogen atoms on methyl groups are
not shown. Only the ipso carbons of the dppe phenyl rings are shown. Relevant pa-
ꢀ
rameters (distances in A and angles in deg.): PteMn ¼ 2.6511(4), PteP(1) ¼ 2.2819(7),
PteP(2) ¼ 2.2353(6), PteS ¼ 2.3179(6), MneS ¼ 2.2908(7), MneC(33) ¼ 1.850(3), Mne
C(34)
Mn
C(35) ¼ 158.7(1), C(33)eMneC(36) ¼ 171.6(1).
¼
1.805(3), MneC(35)
¼
1.799(3), MneC(36)
159.87(3), PteMneC(34)
¼
1.838(4); P(1)ePte
156.50(9), SeMne
¼
163.89(2), P(2)ePteS
¼
¼
indicated by the particularly bent angles at Pt (P(1)ePte
Mn ¼ 163.89(2)ꢀ, P(2)ePteS ¼ 159.87(3)ꢀ) and Mn (PteMne
C(34) ¼ 156.50(9)ꢀ, SeMneC(35) ¼ 158.7(1)ꢀ). This kind of strain is
similar to that in other octahedral thiocarboxylato-bridged com-
plexes [22]. Although the Pt and Mn atoms are further separated
compared to 2, the distance is still suggestive of a PteMn single
bond.
The progress of this reaction was monitored at 30 ꢀC in a large
excess of trans-2,3-dimethylthiirane, providing first order kinetics.
A linear dependence of the first order rate constant kobs vs. thiirane
concentration as well as the negligible solvent effect highly suggest
a bimolecular concerted pathway (Scheme 4).
In order to test our hypothesis that this retention behavior is
most likely due to the unique bridging structure of 2, we inves-
tigated strategies to transform 2 into an analogous non-bridged
species, which would facilitate the desulfurization with inver-
sion of stereochemistry. Thus, the introduction of CO gas in a
With the data represented in this report, we can conclude that
this new “bridged” neopentyl analog 2 undergoes a different pro-
cess for desulfurization of thiiranes owing to the fact that an acyl
bridge is present to force metalemetal proximity. The conse-
quences of this effect appear to be twofold: 1) the manganese
carbonyl moiety is unable to easily dissociate to allow thiirane
coordination to platinum, and facilitate subsequent SN2 attack by
Mn in the S-heterocyclic backbone, and 2) it allows for a “forced”
model of metalemetal cooperativity with the metals chained
benzene solution of
2
smoothly replaced the coordinated
together by an acyl group, effecting a different concerted
Scheme 4. Proposed concerted pathway for desulfurization of thiiranes using bridged species 2.

M.T. Zamora et al. / Journal of Organometallic Chemistry 739 (2013) 6e10
9
4. Experimental
4.1. General comments
All manipulations were carried out under a dry nitrogen or argon
atmosphere using standard Schlenk techniques. All solvents were
dried over and distilled from appropriate drying agents under N2.
The NMR spectra were recorded on a JEOL ECX400P (399.8 MHz for
1H, 161.8 MHz for 31P). The 1H and 31P{1H} chemical shifts are
referenced to TMS and external 85% H3PO4 in D2O, respectively. The
IR spectra were recorded on a JASCO FT/IR-4100 spectrometer using
KBr disks. Elemental analyses were carried out using a PerkineElmer
2400 series II CHN analyzer. Both cis- and trans-2,3-dimethylthiirane
were prepared by literature procedures [24]. The species [(dppe)
PtNpCl] (1) [25], tetramethylthiirane [26], and Na[Mn(CO)5] [27,28]
were prepared as reported previously. All other chemicals were
obtained from commercial sources and used directly without further
purification. Details of time-course experiments and X-ray analyses
are described in the Supplementary data.
Fig. 3. Three-dimensional representation of anti-thiamanganacyclic platinum species
[(dppe)(NpC(O))Pt(trans-SCH(Me)CH(Me)CO)Mn(CO)4] (5anti) showing the numbering
scheme. Thermal ellipsoids are as described in Fig. 1, except for hydrogen atoms, which
are placed at the calculated positions based on the riding model. Hydrogen atoms on
methyl groups are not shown. Only the ipso carbons of the dppe phenyl rings are
4.1.1. [(dppe)Pt(m-C(O)Np-1kC,2kO)eMn(CO)4] (2)
A 30 mL portion of THF was added to a flask containing 1
(0.607 g, 0.867 mmol) and AgNO3 (0.182 g, 1.069 mmol). The
resulting solution was stirred in the dark overnight, resulting in a
pink-colored slurry. The yellow solution was separated from the
pink precipitate by filtered cannula, and added to a second flask
containing a stirring 10 mL green THF solution of Na[Mn(CO)5]
(0.275 g, 1.260 mmol) at ꢁ30 ꢀC, turning the resulting solution
orange in color. The solution was further stirred at ꢁ30 ꢀC for 4 h
and the solvent was removed in vacuo. The red oily solid was dried,
then redissolved in 10 mL of benzene. The insoluble impurities
were separated by filtered cannula and the solvent was removed in
vacuo. The red solid was redissolved in 4 mL of THF and recrystal-
lized by slow diffusion of 10 mL of layered hexane at ꢁ30 ꢀC. The
resulting crystals were washed with 3 ꢂ 5 mL portions of benzene,
redissolved in 7 mL of benzene, and passed through a small Soxhlet
filter. Solvent was removed in vacuo and the solid recrystallized
from THF and hexane, washed with hexane, and dried in vacuo,
giving bright orange crystals (0.554 g, 74%). 1H NMR (399.78 MHz,
ꢀ
shown. Relevant parameters (distances in A and angles in deg.): PteS ¼ 2.372(2), Pte
P(1) ¼ 2.573(2), PteP(2) ¼ 2.343(2), PteC(1) ¼ 2.057(8), MneS ¼ 2.375(2), C(1)e
O(1)
¼
1.21(1); P(1)ePteS
¼
172.72(7), P(2)ePteC(1)
¼
174.4(3), SeMne
C(41) ¼ 168.6(4), C(37)eMneC(38) ¼ 178.7(4), C(39)eMneC(40) ¼ 168.0(4).
desulfurization process, which is likely similar to the desulfuriza-
tion mechanism postulated by Bergman, et al. in heterodinuclear
Ir/Zr systems [23]. Owing to our isolation of the final organome-
tallic species in this process, the bridging thiocarboxylato structure
3, we propose our own variant to this mechanism. In this process,
the bridged species 2 undergoes a concerted bond-breaking-and-
making step to yield the olefin with retention of stereochemistry.
The resulting
m-sulfido, m-acyl complex could then undergo
reductive elimination to form a new sulfur linkage to the acyl
moiety, while producing two mononuclear components. From here,
oxidative addition of the MneS bond to the Pt center could
benzene-d6, 18.0 ꢀC),
d 7.73 (m, 4H), 7.51 (m, 4H), 7.15 (m, 10H), 7.01
generate a new
m-k
2S,O-thiocarboxylato ligand, which can rear-
(m, 2H, dppePh); 2.32 (m, 2H, Np ); 1.91 (m, 2H), 1.72 (m, 2H,
CH2
range to form the thiocarboxylato species 3. In strong support of
this hypothesis, similar rates for the reaction of 2 with a variety
of different thiiranes suggests that the difference in steric bulk has
little-to-no steric effect, which is made evident by the distance
of the substituents from the active site in our mechanism. An
analogous mechanism may be in effect during the transformation
dppeCH CH ); 0.72 (s, 9H, NpMe). 31P{1H} NMR (161.83 MHz, ben-
2
zene-d62, 18.0 ꢀC),
d
53.4 (d, 1P, 2JPeP ¼ 16 Hz, 1JPePt ¼ 2117 Hz, PePte
Mn); 49.2 (d, 1P, 2JPeP ¼ 16 Hz, 1JPePt ¼ 1943 Hz, PePteC(O)Np). IR
(KBr, cmꢁ1): 2046, 2002, 1907, 1869. Anal. Calcd for
C36H35MnO5P2Pt: C, 49.62; H, 3.88. Found: C, 50.30; H, 4.10.
of
5 into 3 following the concerted liberation of olefin,
4.1.2. [(dppe)Pt(m-SC(O)Np)eMn(CO)4] (3)
presumably through the same proposed (
intermediate.
m-sulfido)(acyl)platinum
Route 1: A 4 mL portion of benzene was added to a flask con-
taining 2 (0.165 g, 0.191 mmol). The resulting solution was stirred
for 10 min at room temperature, followed by rapid injection of
3. Conclusions
trans- (or cis-)2,3-dimethylthiirane (20 mL, 0.22 mmol). The solution
was heated to 50 ꢀC and stirred for 2 h, wherein it changed from
bright to dark orange. The solution was filtered via cannula into
5 mL of hexane. The heterogeneous mixture was filtered again via
cannula, and the black precipitate discarded. Solvent was removed
in vacuo and the sample redissolved in 1 mL of THF, and recrys-
tallized by layering 10 mL of hexane and storing at ꢁ30 ꢀC over-
night, giving a dark orange powder. The sample was washed with
5 ꢂ 5 mL portions of hexane before drying in vacuo, giving a dark
orange crystalline material (0.145 g, 85%). Route 2. A 4 mL portion of
benzene was added to a flask containing 5syn (or 5anti) (0.115 g,
0.130 mmol). The resulting solution was heated to 50 ꢀC and stirred
for 2 h, wherein it changed from dark yellow to dark orange. The
solution was filtered via cannula into 5 mL of hexane. Solvent was
The forced-proximity in a heterodinuclear Pt/Mn complex in-
hibits dissociation of the Mn moiety, preventing SN2 reactivity with
thiiranes, and proceeds to undergo CeS bond cleave via retention of
stereochemistry. Kinetic analyses support a concerted, bimolecular
pathway. The acyl bridge can be released by coordination of another
CO ligand to Mn, which results in a terminal acyl species with an
unsupported metalemetal bond. This species exhibits similar reac-
tivity to the previously-reported methyl and ethyl cases, facilitating
desulfurization of thiiranes with inversion of stereochemistry.
Further studies, involving detailed kinetics to clarify the mechanism
of this direct desulfurization process, as well as investigations to
potentially make these systems catalytic are in progress.

10
M.T. Zamora et al. / Journal of Organometallic Chemistry 739 (2013) 6e10
removed in vacuo and purified as in Route 1, giving a dark orange
Acknowledgments
crystalline material (0.145 g, 89%). 1H NMR (399.78 MHz, C6D6,
18.6 ꢀC):
d
7.67 (br m, 6H), 7.08 (m, 14H, dppePh); 2.01e1.73 (m, 4H,
We thank the Ministry of Education, Sports, Culture, Science,
and Technology, Japan and Tokyo University of Agriculture and
Technology for financial support for this research. In addition, we
acknowledge support from the Japan Society for the Promotion of
Science in the form of a postdoctoral fellowship to M.T.Z.
dppeCH CH ); 1.55 (s, 2H, NpCH ); 0.87 (s, 9H, NpMe). 31P{1H} NMR
(161.832MHz, C6D6, 19.0 ꢀC),
d
620.7 (s, 1P, 1JPePt ¼ 4053 Hz, PePteS);
2
59.7 (s, 1P, 1JPePt ¼ 2871 Hz, PePteMn).
4.1.3. [(dppe)(NpC(O))PteMn(CO)5] (4)
A 5 mL portion of benzene was added to a flask containing 2
(0.506 g, 0.589 mmol). The resulting solution was cooled to
ꢁ196 ꢀC, and the headspace removed in vacuo. The solution was
allowed to warm to room temperature, at which point the head-
space was filled with an atmosphere of CO(g). The solution was
stirred overnight, wherein it changed from dark red to a bright
yellow color. The solvent was removed and the crude product dried
under vacuum, giving a yellow powder. The crude sample was
redissolved in 5 mL of THF, and recrystallized by layering 20 mL of
hexane and storing at ꢁ30 ꢀC overnight, giving a bright yellow
powder. The sample was washed with 5 ꢂ 5 mL portions of hexane
before drying in vacuo, giving a bright yellow crystalline material
Appendix A. Supplementary material
CCDC Nos. 922487 (for 2), 922489 (for 3), and 922488 (for 5anti),
contain the supplementary crystallographic data for this paper.
These data can be obtained free of charge via http://www.ccdc.cam.
ac.uk/data_request/cif.
Appendix B. Supplementary data
Figures depicting the solvent dependence of the rate in the
reaction of 2 and 4 with trans-2,3-dimethylthiirane, sample pseudo
first order plots of the reaction of the bridged species with various
amounts of trans-2,3-dimethylthiirane; as well as tables of crys-
tallographic experimental details for 2, 3, and 5anti. Supplementary
data related to this article can be found at http://dx.doi.org/10.1016/
j.jorganchem.2013.04.003.
(0.510 g, 98%). 1H NMR (399.78 MHz, C6D6, 21.9 ꢀC):
4H), 7.73 (m, 4H), 7.62 (br m, 4H), 7.00 (br m, 8H, dppePh); 2.10 (m,
d 8.07 (br m,
2H), 1.77 (m, dppeCH CH ); 1.54 (s, 2H, NpCH ); 0.89 (s, 9H, NpMe). 31
P
2
2
{1H} NMR (161.83 MHz,2C6D6, 21.9 ꢀC),
d
39.3 (s, 1P, 1JPePt ¼ 3568 Hz,
PePteMn); 36.1 (s, 1P, 2JPePt ¼ 16 Hz, 1JPePt ¼ 1338 Hz, PePteC(O)
Np). IR (KBr, cmꢁ1): 1619 (s, C]O).
4.1.4. [(dppe)(NpC(O))Pt(cis-SCH(Me)CH(Me)CO)Mn(CO)4] (5syn
)
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6449.
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tallics 25 (2006) 3867e3875.
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dimethylthiirane (15
mL, 0.17 mmol). The solution was stirred
overnight, wherein it changed from bright to dark yellow. The
solvent was removed and the crude product washed with 5 ꢂ 5 mL
portions of hexane before being dried under vacuum, giving a dark
yellow powder. The crude sample was redissolved in 2 mL of
benzene, and recrystallized by layering 10 mL of diethyl ether and
10 mL of hexane and storing at ꢁ30 ꢀC overnight, giving a dark
yellow powder. The sample was washed with 5 ꢂ 5 mL portions of
hexane before drying in vacuo, giving a dark yellow crystalline
material (0.086 g, 78%). 1H NMR (399.78 MHz, acetone-d6, 22.1 ꢀC):
d
8.21 (br m, 4H), 7.70 (m, 4H), 7.49 (br m, 4H), 7.43 (br m, 8H,
dppePh); 3.09 (br, 1H, CH); 2.55e2.67 (m, 4H, dppe
); 1.44 (br,
CH2CH2
1H, CH); 1.43 (s, 2H, NpCH ); 1.12 (d, 3H, 3JHeH ¼ 6.7 Hz, Me); 0.81 (s,
[13] M. Cowie, Can. J. Chem. 83 (2005) 1043e1055.
2
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Dordrecht, 2005.
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lishers, Varna, 1998.
3
9H, NpMe); 0.76 (d, 3H, JHeH ¼ 6.5 Hz, Me). 31P{1H} NMR
(161.83 MHz, acetone-d6, 22.5 ꢀC),
d
34.3 (s, 1P, 1JPePt ¼ 3575 Hz, Pe
PteS); 32.9 (s, 1P, 1JPePt ¼ 1320 Hz, PePteC(O)Np).
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(2001) 2065e2075.
4.1.5. [(dppe)(NpC(O))Pt(trans-SCH(Me)CH(Me)CO)Mn(CO)4]
(5anti
The desired product was prepared and purified as described for
5syn using 4 (0.101 g, 0.114 mmol) and cis-dimethylthiirane (15 L,
)
m
0.165 mmol). The sample was washed with 5 ꢂ 5 mL portions of
hexane before drying in vacuo, giving a dark yellow crystalline
material (0.081 g, 73%). 1H NMR (399.78 MHz, acetone-d6, 22.1 ꢀC):
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Chim. Acta 359 (2006) 3699e3708.
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109 (1987) 1995e2002.
d
8.26 (br m, 4H), 7.63 (m, 4H), 7.53 (br m, 4H), 7.47 (br m, 8H,
3
dppePh); 2.48e2.84 (m, 4H, dppeCH CH ); 2.23 (dq, 1H, JHe
2
2
3
3
3
¼ 12.1 Hz, JHeH ¼ 6.4 Hz), 1.91 (dq, 1H, JHeH ¼ 12.1 Hz, JHe
H
¼ 6.4 Hz, CH); 1.54 (s, 2H, Np ); 1.54 (d, 3H, 3JHeH ¼ 6.4 Hz), 0.81
H
CH2
(d, 3H, JHeH ¼ 6.4 Hz, Me); 0.67 (s, 9H, NpMe). 31P{1H} NMR
3
(161.83 MHz, acetone-d6, 22.3 ꢀC),
d
34.3 (s, 1P, 1JPePt ¼ 3545 Hz, Pe
PteS); 31.5 (s, 1P, 1JPePt ¼ 1329 Hz, PePteC(O)Np).