Synthesis, characterization, and coordination chemistry of phosphines with ethylenedioxythiophene substituents

Article abstract of DOI:10.1139/v05-004

The preparation of several new phosphines bearing one or more 3,4-ethylenedioxythiophene (EDOT) units as substituents linked at the 2-thienyl position is described. The phosphines were prepared by reaction of lithiated EDOT intermediates with appropriate

Full text of DOI:10.1139/v05-004

150
Synthesis, characterization, and coordination
chemistry of phosphines with
ethylenedioxythiophene substituents
M’hamed Chahma, Daniel J.T. Myles, and Robin G. Hicks
Abstract: The preparation of several new phosphines bearing one or more 3,4-ethylenedioxythiophene (EDOT) units as
substituents linked at the 2-thienyl position is described. The phosphines were prepared by reaction of lithiated EDOT
intermediates with appropriate chlorophosphines to afford (3,4-ethylenedioxy-2-thienyl)diphenylphosphine (1), (bis(3,4-
ethylenedioxy-2-thienyl)phenylphosphine (2), tris(3,4-ethylenedioxy-2-thienyl)phosphine (3), 2,5-bis(diphenylphosphino)-
3,4-ethylenedioxythiophene (4), and 2-diphenylphosphino-5-mesitylthio-3,4-ethylenedioxythiophene (5). Molybdenum
carbonyl complexes of compounds 1–3 were prepared by reaction of the phosphine ligands with cis-Mo(CO)4(pip)2. In
all cases, spectroscopic evidence is fully consistent with the phosphines acting as monodentate, P-bound ligands. Elec-
trochemical studies on the phosphines as well as their metal complexes indicate that the normal electrochemical redox
robustness of the EDOT group is dramatically decreased by the presence of phosphine substituents: all compounds ex-
hibited irreversible oxidation processes and no evidence of electropolymerization was observed for the phosphines bear-
ing two or three EDOT groups.
Key words: phosphines, thiophene, 3,4-ethylenedioxythiophene, EDOT, electrochemistry, coordination complexes.
Résumé : On décrit la préparation de plusieurs nouvelles phosphines portant un ou plusieurs unités de 3,4-éthylènedi-
oxythiophène (EDOT) comme substituants liés à la position 2-thiényle. On a préparé les phosphines par la réaction
d’intermédiaires EDOT lithiés avec les chlorophosphines appropriées qui ont conduit à la formation des (3,4-éthylènedi-
oxy-2-thiényl)diphénylphosphine (1), bis(3,4-éthylènedioxy-2-thiényl)phénylphosphine (2), tris(3,4-éthylènedioxy-2-
thiényl)phosphine (3), 2,5-bis(diphénylphosphino)-3,4-éthylènedioxythiophène (4) et 2-diphénylphosphino-5-mésitylthio-
3,4-éthylènedioxythiophène (5). La réaction des ligands phosphines avec les cis-Mo(CO)4(pip)2 a permis de préparer les
complexes du molybdène carbonyle des composés 1–3. Dans tous les cas, les données spectroscopiques sont en total
accord avec le fait que les phosphines agissent comme des ligands monodentates liés par le phosphore. Des études
électrochimiques sur les phosphines ainsi que sur leurs complexes métalliques indiquent que la solidité redox électro-
chimique normale du groupe EDOT est dramatiquement abaissée par la présence des substituants phosphines : tous les
composés donnent lieu à des processus d’oxydation irréversibles et aucune électropolymérisation n’a été observée avec
les phosphines portant deux ou trois groupes EDOT.
Mots clés : phosphines, thiophène, 3,4-éthylènedioxythiophène, EDOT, électrochimie, complexes de coordination.
[Traduit par la Rédaction] Chahma et al. 155
Introduction
arylphosphine derivatives have been explored in which some
or all of the phenyl groups have been replaced by hetero-
aromatic rings such as pyridine (3) and furan (4). Phos-
phines containing thiophene subtitutents have also received
attention. Although they typically behave as simple P-mono-
dentate ligands (5), thienylphosphines can also act as bridg-
ing ligands via the thiophene sulfur atom (6), or as chelating
ligands involving cyclometallation of one of the thiophene
rings (7).
Thienylphosphine complexes have also attracted interest
because of the possibility of making phosphine-substituted
conjugated polythiophenes in which the electronic properties
of the polymer can be tuned via metal coordination at the
phosphine (8). Metal–organic polymers have received a great
deal of interest stemming from the potential properties that
may arise from polymers containing both organic and inor-
ganic elements (9). There has been a particularly strong em-
phasis on polymers containing metals as part of, or attached
to, conjugated frameworks (10). The main motivation behind
The importance of phosphine ligands in (organo)transition
metal chemistry cannot be overstated. The ability to modu-
late steric and electronic properties of phosphines (1) and
their resulting metal complexes has facilitated the develop-
ment of metal phosphine-based catalysis in a wide range of
forums, particularly in late metal-catalyzed cross-coupling
reactions (Suzuki, Stille, Kumada–Corriu, etc.) (2). As one
of the prototypical members of this ligand class, triphenyl-
phosphine is a true benchmark ligand. In recent years, other
Received 5 August 2004. Published on the NRC Research
Press Web site at http://canjchem.nrc.ca on 24 February 2005.
M. Chahma, D.J.T. Myles, and R.G. Hicks.1 Department of
Chemistry, University of Victoria, PO Box 3065 STN CSC,
Victoria, BC V8W 3V6, Canada.
1Corresponding author (e-mail: rhicks@uvic.ca).
Can. J. Chem. 83: 150–155 (2005)
doi: 10.1139/V05-004
© 2005 NRC Canada

Chahma et al.
151
Scheme 1.
Scheme 2.
Table 1. Characterization data for EDOT–phosphines 1–5 and re-
lated compounds.
λmax
(nm)
31P NMR Ep
δ (ppm)
Compound
(V vs. Fc/Fc+)
EDOT
260
274
274
277
292
—
+0.93
+0.79
+0.68
+0.60
+0.52
+0.57
+0.40a
EDOT–PPh2 (1)
(EDOT)2PPh (2)
(EDOT)3P (3)
Ph2P-EDOT-PPh2 (4)
MesS-EDOT-PPh2 (5)
MesS-EDOT-SMes (6)
–28.1
–50.5
–68.5
–26.5
288, 305 –27.6
305
—
aReversible.
In addition to compounds 1–4, an EDOT derivative with
one diphenylphosphine (Ph2P) and one mesitylthio (MesS)
substituent was prepared for comparison of electrochemical
properties. Compound 5 was synthesized from 5-bromo-2-
(mesitylthio)-3,4-ethylenedioxythiophene) (13) via lithium–
halogen exchange followed by treatment with Ph2PCl using
analogous protocols employed in the synthesis of 1–4.
(Scheme 2).
these studies is to explore the possibilities of making new
materials, which combine inherent functional properties of
purely organic conjugated polymers (11) such as conductiv-
ity, electrochromism, and light emission with the electroni-
cally interesting features of metal complexes (magnetic,
optical, etc.).
Although some EDOT derivatives with unsubstituted
thiophene α-carbon atoms are unstable to air and moisture,
all of the EDOT phosphines are air-stable compounds. Ta-
ble 1 summarizes pertinent physicochemical data for the
new EDOT-substituted phosphines as well as EDOT itself
and 2,5-bis(mesitylthio)3,4-ethylenedioxythiophene (6), a
disubstituted EDOT derivative previously made in our
lab.(13) The UV–vis spectra all have lowest energy absorp-
tion maxima in the neighborhood of 277–290 nm. These are
all slightly red-shifted relative to EDOT itself (λmax =
260 nm) indicative of a weak electronic perturbation of the
EDOT chromophore by the phosphine moieties. The 31P NMR
chemical shifts of the series (EDOT)nPPh3–n progress
smoothly to more negative values as phenyl groups are suc-
cessively replaced by more electron-rich EDOT moieties.
Analogous behaviour is observed in the related series
of unsubstituted 2-thienyl–phenylphosphines (2-Th)nPPh3–n
(Fig. 1) (6a). Similar trends can also be found in triaryl-
phosphines bearing para substituents, for which the more
electron-donating groups give rise to more negative δ 31P
NMR values (14).
Among the many thiophenes that have been incorporated
into conjugated organic polymers, 3,4-ethylendioxythiophene
(EDOT) stands out as an electron-rich derivative. The
strongly electron-donating oxygen atoms render EDOT rela-
tively easily oxidized and impart exceptional stability to the
resulting homopolymer. The outstanding properties of
poly(EDOT) have led to the synthesis and study of a wide
range of hybrid materials of EDOT with other organic and
inorganic moieties (12). However, no EDOT-substituted
phosphines have been reported. It occurred to us that such
species should be useful ligands and may lead to interesting
materials from hybrid EDOT–phosphine–metal complexes
and polymers. To this end, herein we describe the synthesis,
characterization, and preliminary coordination chemistry of
triarylphosphine derivatives bearing 3,4-ethylenedioxy-2-
thienyl groups as substituents.
Synthesis and characterization of EDOT
phosphines
The EDOT–phosphine derivatives were prepared by reac-
tions of in-situ-generated, lithiated EDOT compounds with
the appropriate chlorophosphine (Scheme 1). Thus, Li+EDOT–
reacts with chlorodiphenylphosphine, dichlorophenylphos-
phine, and trichlorophosphine to give Ph2P(EDOT) (1),
PhP(EDOT)2 (2), and P(EDOT)3 (3), respectively. In addi-
tion, 2,5-bis(diphenylphosphino)-3,4-ethylenedioxythiophene
(Ph2P-EDOT-PPh2) (4) was prepared by reaction of chloro-
diphenylphosphine with doubly lithiated EDOT.
The redox properties of compounds 1–5 were examined
by cyclic voltammetry. All new compounds 1–5 exhibited ir-
reversible oxidation waves at the potentials given in Table 1.
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152
Can. J. Chem. Vol. 83, 2005
Table 2. Characterization data for Mo complexes of EDOT phosphines and related compounds.
Compound
31P NMR δ (ppm)
ν(CO) (cm–1)
Ep (V vs. Fc/Fc+)
cis-Mo(CO)4(EPPh2)2 (7)
Mo(CO)5(E2PPh) (8)
Mo(CO)5(E3P) (9)
cis-Mo(CO)4(ThPPh2)26c
Mo(CO)5(Th2PPh)6c
Mo(CO)5(Th3P)6c
+24.3
+7.6
2023m, 1924s, 1908s, 1878m
1992w, 1946sh
+0.32
+0.67
+0.69
—
–8.5
1990w, 1947sh
+26.7
+15.0
+6.6
2010, 1900, 1880
2020, 1945, 1905, 1885
2020, 1945, 1910, 1890
—
—
Fig. 1. 31P NMR chemical shifts for (2-thienyl)phenylphosphines
(data from ref. 14) and (3,4-ethylenedioxy-2-
thienyl)phenylphosphines.
Fig. 2. CV of 2 × 10–4 mol/L of 6 (a) alone and (b) with
1 equiv. of Ph3P added.
For compounds 1–3, the irreversible nature of the oxidation
was not unexpected because the EDOT groups in these com-
pounds contain unsubstituted positions on the thiophene
ring. These unsubstituted positions are known to be highly
reactive sites in oxidized thiophenes. However, the bis(phos-
phine)-substituted EDOT 4 and 5-mesitylthio-2-diphenyl-
phosphine-3,4-ethylenedioxythiohene (5) also exhibited
irreversible behaviour upon oxidation. Thiophenes contain-
ing substituents at all the 2 (or 5) positions generally can be
electrochemically oxidized to give radical cations that are
stable at least on electrochemical timescales, For example,
bis(mesitylthio)EDOT 6 undergoes a fully reversible oxida-
tion to its radical cation at +0.40 mV. Evidently, the pres-
ence of a phosphine group on one of the a carbon atoms of
EDOT render the oxidation of the latter moiety irreversible.
In general, the oxidation of thiophene derivatives bearing
two or more unsubstituted α-carbon atoms are irreversibly ox-
idized because the resulting radical cations couple at these
carbons — this is the first step in the electropolymerization
of thiophene and its derivatives. The source of instability in
compounds 1–5 appears to arise from reactions specific to
phosphine-containing thiophenes: although, in principle,
compounds 2 and 3 could lead to poly(thiophene–phosphine)
materials upon oxidation, repeated electrochemical cycling
lead to passivation of the electrode and no formation of
polymer was observed. Similar behavior was observed in
related phosphinoterthiophenes (8e). As a final piece of sup-
porting evidence, the reversibility of the electrochemical
oxidation of 6 is dramatically decreased upon addition of
triphenylphosphine (Fig. 2).
carbonyl species; related complexes of other 2-thienyl-
phosphines have been reported (6b, 6c, 6f). Reactions of 1
with the reagent cis-Mo(CO)4(piperidine)2 (15) led to the ex-
pected cis-disubstituted product cis-Mo(CO)4(EPPh2)2 (7).
However, reactions of 2 or 3 with cis-Mo(CO)4(piperidine)2
in a 2:1 ratio did gave mixtures of products, which appeared
to contain the monosubstituted products Mo(CO)5(PAr3) in
addition to the anticipated disubstituted products. Changing
the stoichiometric ratio of phosphines to Mo to 1:1 produced
the monosubstituted products 8 and 9 in high yields. These
unexpected products must result from intermolecular CO
transfer and may be a consequence of the larger steric bulk
of the phosphines bearing multiple EDOT substituents. The
qualitative similarity of an EDOT group to a naphthyl group
would lead to approximately similar steric features between
(EDOT)3P (3) and tris(1-naphthyl)phosphine, the latter of
which has a cone angle of ~200° (1c).
The product identities were confirmed through a combina-
tion of IR, NMR, and mass spectroscopies. The 31P NMR
chemical shifts (see Table 2) of the complexes are 52–
60 ppm upfield relative to the chemical shifts of the free
ligand, indicative of P-coordinated phosphines. The proton
and carbon NMR suggest simple P-monodentate coordina-
tion modes for all three phosphines; no evidence of either
cyclometallation of S-donating binding is detected. The 13C
Coordination complexes
Preliminary investigations into the coordination chemistry
of the phosphines involved reactions with molybdenum
© 2005 NRC Canada

Chahma et al.
153
NMR spectra were particularly informative as the magnitude
of the carbon–phosphorus coupling constants to the carbonyl
groups provided strong support for the cis-disubstituted ge-
ometry of 7 as well as the monosubstituted nature of 8 and
9. Parent molecular anions were observed in the mass spec-
tra of all three complexes. However, these are all relatively
weak compared with the base peaks, which in each case cor-
respond to the loss of two carbonyls. This process may well
be facilitated by chelation of an ethylenedioxy oxygen atom
of the EDOT–phosphines (see the following). The ν(CO)
frequencies are quite similar to those observed in related
molybdenum carbonyl complexes of 2-thienylphosphines, a
feature that suggests that the π-electron-rich nature of the
EDOT moiety is not strongly felt by the metal center in
these complexes.
Cyclic voltammetry studies on complexes 7–9 revealed ir-
reversible oxidations for all three compounds. Interestingly,
the oxidation peak potential for complexes 8 and 9 are very
similar to the peak potentials for the corresponding free
ligand, whereas the peak potential for 7 is some 0.4 V lower
than its free phosphine ligand. This may be related to the
fact that 7 has two EDOT phosphine ligands whereas 8 and
9 have one each, although the irreversibility of the oxida-
tions renders direct comparisons difficult owing to the scan
rate dependence of these processes. Attempts to electropoly-
merize 7–9 by repeated electrochemical cycling failed, in-
stead leading to electrode passivation.
Studies aimed at exploring the potential coordinative versa-
tility of these ligands are in progress.
Experimental
General considerations
All reagents were purchased from Aldrich and used as re-
ceived; Mo(CO)4(piperdine)2 was prepared according to lit-
erature procedures (15). All reactions were performed under
an atmosphere of dry argon using standard Schlenk or glove
box techniques. Solvents were dried and distilled under ar-
gon prior to use (CH2Cl2, CaH2; THF, Na–benzophenone).
Mass spectra were recorded on a Kratos Concept IH mass
spectrometer system. IR spectra were recorded as Nujol
mulls or KBr presses on a PerkinElmer Spectrum One spec-
trometer. NMR spectra were recorded on a Bruker AMX360
spectrometer. Cyclic voltammetry experiments were per-
formed using a CV-50W voltammetric analyzer (BAS) at
room temperature (22 2 °C). Voltammetric measurements
were performed in CH2Cl2 containing 1 mol/L of n-Bu4NBF4.
The platinum electrode (BAS, diameter 1.6 mm) was used as
the working electrode. Platinum and silver wires were used
as auxiliary and reference electrodes, respectively. The refer-
ence electrode was calibrated vs. ferrocene/ferrocenium
redox (E° = 0.440 vs. Ag/AgCl) internal reference. The
working electrode was polished on alumina before use. iR
compensations were applied for all experiments.
Conclusions
We have described the synthesis and characterization of a
new series of phosphines bearing ethylenedioxythiophene
substituents. Characterization of the phosphines as well as
metal complexes thereof suggest there is little electronic per-
turbation of the EDOT group by the phosphine and vice
versa. In sharp contrast to other lone-pair-containing sub-
stituents (e.g., -OR, -SR) that can enhance the redox stability
of thiophenes, phosphine groups do not offer much in the
way of electrochemical stability at all and in fact can de-
stabilize the otherwise inherently robust redox characteristics
of the EDOT moiety. In a similar vein, it appears that the
electron richness of the EDOT ring is not manifested in a
more “electron-rich” metal center in coordination complexes —
at least for the ones presented herein. Nonetheless, these
compounds should be useful additions to the stable of aryl-
phosphine ligands because of their ease of synthesis, vari-
able steric bulk, and in particular because of the potential
modes of coordination they offer: As simple monodentate
mode A, bidentate (P/S) bridging ligands in polynuclear sys-
tems B, or chelating (P/O) chelating C — the latter two hav-
ing the potential to be hemilabile coordination modes (16).
General synthesis of (3,4-ethylenedioxy-2-thienyl)
phosphine derivatives
The synthesis of EDOT-substituted phosphines 1–4 is ex-
emplified by the synthesis of 1. EDOT (1.313 g, 9.25 mmol)
was dissolved in THF (50 mL) and treated with n-BuLi
(1.6 mol/L, 3 mL, 9.36 mmol) at room temperature. After
2 h of stirring, the mixture was cooled to –78 °C and
chlorodiphenylphosphine (3 mL, 3.1 mmol) was added
dropwise to the reaction mixture. The mixture was stirred at
–78 °C for 2 h and gradually brought to room temperature.
The mixture was then poured into water (100 mL) and ex-
tracted using CH2Cl2 (2 × 100 mL). The organic layers were
combined and dried over anhydr. MgSO4. Removal of the
solvent gave a crude product, which was purified by chroma-
tography using silica gel and chloroform as the eluent. The
product was then recrystallized in CH2Cl2–methanol.
(3,4-Ethylenedioxy-2-thienyl)diphenylphosphine (EDOT-
PPh2, 1)
Yield: 74%; mp 84 °C. UV–vis (CH2Cl2): λmax (ε)
1
274 nm (16 450 M–1 cm–1). H NMR (CD2Cl2, 300 MHz) δ:
4.20 (m, 4H), 6.60 (s, 1H), 7.40 (m, 10H). 13C NMR
(CD2Cl2, 125 MHz) δ: 64.94 (CH2), 65.41 (CH2), 106.22
(CH), 109.95 (C, d, J = 28.6 Hz), 128.75 (4CH, d, J =
6.8 Hz), 129.23 (2CH), 133.54 (4CH, d, J = 20.2 Hz),
137.24 (2C, d, J = 8.6 Hz), 142.72 (C, d, J = 3.7 Hz), 147.01
(2C, d, J = 18.9 Hz). 31P NMR (CD2Cl2, 145 MHz) δ:
–28.12. HR-MS calcd. for C18H15O2PS: 326.0530; found:
326.0535. Anal. calcd. for C18H15O2P (%): C 66.25, H 4.63,
O 9.80; found: C 66.21, H 4.17, O 9.95.
© 2005 NRC Canada

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Can. J. Chem. Vol. 83, 2005
(yield 43%); mp 115 °C. IR ν(CO) cm–1: 2023, 1924, 1908,
1878. 1H NMR (CD2Cl2, 300 MHz) δ: 4.10 (m, 8H), 6.60 (d,
J = 2.10 Hz, 2H), 7.20 (m, 8H), 7.40 (m, 12). 13C NMR
(CD2Cl2, 125 MHz) δ: 64.60 (CH2), 64.80 (CH2), 105.50
(CH), 109.80 (C, dd, J = 12.5 Hz), 128.30 (C, t, J = 4.6 Hz),
130.00 (CH) 133.40 (C, t, J = 6.8 Hz), 135.90 (C, dt, J =
15.5 Hz), 143.20 (C, t, J = 3 Hz), 145.70 (C, t, J = 3.7 Hz),
210.20 (C, t, J = 9.4 Hz), 215.6 (C, t, J = 9.3 Hz). 31P NMR
(CD2Cl2, 145 MHz) δ: 24.3. HR-MS calcd. for
C40H30MoO8P2S2: 861.9912; found: 861.9911. Anal. calcd.
for C40H30MoO8P2S2 (%): C 55.82, H 3.51, O 14.87, P 7.20;
found: C 54.70, H 3.67, O 15.36, P 7.07.
Bis(3,4-ethylenedioxy-2-thienyl)phenylphosphine
((EDOT)2PPh, 2)
Yield: 74%; mp 137 °C. UV–vis (CH2Cl2): λmax (ε)
1
274 nm (21 500 M–1 cm–1). H NMR (CD2Cl2, 300 MHz) δ:
4.20 (m, 8H), 6.60 (s, 2H), 7.40 (m, 5H). 13C NMR (CD2Cl2,
125 MHz) δ: 64.91 (2CH2), 65.42 (2CH2), 106.31 (2CH),
109.22 (C, d, J = 25.5 Hz), 128.62 (2CH, d, J = 6.8 Hz),
129.12 (CH), 132.48 (2CH, d, J = 19.8 Hz), 136.95 (2C, d,
J = 6.3 Hz) 142.53 (2C, d, J = 4 Hz), 146.90 (2 C, d, J =
20.5 Hz). 31P NMR (CD2Cl2, 145 MHz) δ: –50.5. HR-MS
calcd. for C18H15O4PS2: 390.0149; found: 390.0144. Anal.
calcd. for C18H15O4PS2 (%): C 55.38, H 3.87, O 16.39;
found: C 54.60, H 3.89, O 16.39.
Syntheses of Mo(CO)5(PAr3) (8, PAr3 = 2)
Complex 8 was prepared in an analogous fashion to 9.
Yield: 70%; mp 172 °C. Irν(CO) cm–1: 1946. 1H NMR
(CD2Cl2, 300 MHz) δ: 4.20 (s, 8H) 6.70 (d, J = 2.2 Hz, 2H),
7.40 (m, 3H), 7.60 (m, 3H). 13C NMR (CD2Cl2, 125 MHz) δ:
64.90 (CH2), 65.30 (CH2),106.70 (CH, d, J = 2.4 Hz), 128.8
(CH, d, J = 9.8 Hz), 130.8 (CH), 132.20 (CH, d, J =
13.1 Hz), 135.30 (C, d, J = 39.9 Hz), 143.20 (C, d, J =
6.4 Hz), 146.4 (C, d, J = 8.1 Hz), 206.40 (C, d, J = 9.5 Hz),
211.60 (C, d, J = 24.7 Hz). 31P NMR (CD2Cl2, 145 MHz) δ:
7.6. HR-MS calcd. for C23H15MoO9PS2: 627.8950; found:
627.8985.
Tris(3,4-ethylenedioxy-2-thienyl)phosphine ((EDOT)3P, 3)
Yield: 77%; mp 181 °C. UV–vis (CH2Cl2): λmax (ε)
1
277 nm (25 450 M–1 cm–1). H NMR (CD2Cl2, 300 MHz) δ:
4.20 (m, 12H), 6.60 (s, 3H). 13C NMR (CD2Cl2, 125 MHz)
δ: 64.90 (CH2), 65.43 (CH2), 106.15 (CH), 108.75 (C, d, J =
22.6 Hz), 142.47 (C, d, J = 4.5 Hz), 146.14 (C, d, J =
21.5 Hz). 31P NMR (CD2Cl2, 145 MHz) δ: –50.54. HR-MS
calcd. for C18H15O6PS3: 453.9768; found: 453.9757. Anal.
calcd. for C18H15O6PS3 (%): C 47.57, H 3.33, O 21.12;
found: C 47.07, H 3.17, O 21.97.
2,5-Bis(diphenylphosphinyl)-3,4-ethylenedioxythiophene
(Ph2P-EDOT-PPh2, 4)
Syntheses of Mo(CO)5(PAr3) (9, PAr3 = 3)
cis-Mo(CO)4(piperidine)2 (1.154 g, 3 mmol) was added to
a solution of 3 (0.422 g, 0.9 mmol) in CH2Cl2 (10 mL) at
room temperature. The mixture was stirred overnight and fil-
tered through a pad of silica gel. The product was isolated
by precipitation from pentane. Yield: 60%; mp 202 °C. IR
Yield: 63%; mp 101 °C. UV–vis (CH2Cl2): λmax (ε)
1
292 nm (25 230 M–1 cm–1). H NMR (CD2Cl2, 300 MHz) δ:
4.20 (s, 4H), 7.40 (m, 20H). 13C NMR (CD2Cl2, 125 MHz)
δ: 65.14 (CH2), 116.35 (C, d, J = 31.3 Hz), 128.74 (CH, d,
J = 7.5 Hz), 129.29 (CH), 133.57 (CH, d, J = 20.4 Hz),
136.79 (C, d, J = 8.8 Hz), 146.91 (C, dd, J = 2.9 Hz, J =
17.9 Hz). 31P NMR (CD2Cl2, 145 MHz) δ: –26.5. HR-MS
calcd. for C30H24O2P2S: 510.0972; found: 510.0963. Anal.
calcd. for C30H24O2P2S (%): C 70.58, H 4.74, O 6.27,
P 12.13; found: C 67.97, H 4.48, O 6.67, P 11.67.
1
ν(CO) cm–1: 1947. H NMR (CD2Cl2, 300 MHz) δ: 4.10 (m,
8H), 6.60 (d, J = 2.9 Hz, 2H). 13C NMR (CD2Cl2, 125 MHz)
δ: 64.70 (CH2), 65.00 (CH2), 106.30 (CH), 107.10 (C, d, J =
36.7 Hz), 142.70 (C, d, J = 7.3 Hz), 145.8 (C, d, J =
10.6 Hz), 206.0 (C, d, J = 9.5 Hz), 211.60 (C, d, J =
24.6 Hz). 31P NMR (CD2Cl2, 145 MHz) δ: –8.5. HR-MS
calcd. for C23H15MoO11PS3: 691.8569; found: 691.8618.
Anal. calcd. for C23H15MoO11PS3 (%): C 40.01, H 2.19, O
25.49, S 13.93, P 4.49; found: C 39.99, H 2.22, O 25.65, S
14.34, P 4.44.
2-Diphenylphosphinyl-5-mesitylthio-3,4-
ethylenedioxythiophene (MesS-EDOT-PPh2, 5)
1
Yield: 70%; mp 102 °C. H NMR (CD2Cl2, 300 MHz) δ:
2.30 (s, 3H), 2.50 (s, 6H), 4.2 (m, 4H), 6.90 (s, 2H), 7.30
(m, 10H). 13C NMR (CD2Cl2, 125 MHz) δ: 21.33 (CH3),
22.34 (2CH3), 65.35 (CH2), 65.37 (CH2), 110.97 (2C, d, J =
31.6 Hz), 116.00 (2C), 128.97 (4CH, d, J = 6.8 Hz), 129.48
(2CH), 129.79 (2CH) 133.68 (4CH, d, J = 19.2 Hz), 137.12
(C, d, J = 7.9), 139.65 (C), 142.65 (C, d, J = 3.4 Hz), 143.21
(C), 146.71 (2C, d, J = 19.2 Hz). 31P NMR (CD2Cl2,
145 MHz) δ: –27.6. HR-MS calcd. for C27H25O6PS2:
476.1034; found: 476.1033. Anal. calcd. for C27H25O6PS2
(%): C 68.04, H 5.29, O 6.71, P 7.93; found: C 67.58,
H 4.96, O 7.12, P 6.08.
Acknowledgements
We thank the University of Victoria, the Natural Sciences
and Engineering Research Council of Canada (NSERC), and
Defence R&D Canada-Atlantic for support.
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