Phosphorus-Carbon Bond Forming Reactions of Diphenylphosphenium and Diphenylphosphine Triflate Complexes of Tungsten

Article abstract of DOI:10.1021/acs.organomet.6b00348

The complex [W(CO)₅{PClPh₂}] reacts with AlCl₃ to form a mixture of the phosphenium complex [W(CO)₅{PPh₂}][AlCl₄] and an isocarbonyl, with GaCl₃ to form [W(CO)₅{PPh₂}][GaCl₄], and with silver trifluoromethanesulfonate to form [W(CO)₅{P(OSO₂CF₃)Ph₂}]. All three complexes react as strong P electrophiles, undergoing electrophilic substitution reactions with aromatic and heteroaromatic compounds, alkenes, and alkynes, to form aromatic and heteroaromatic phosphines, allyl phosphines, and alkynyl phosphines, respectively. Alkenes lacking cleavable γ-H atoms and internal alkynes undergo tandem electrophilic addition/substitution reactions, adding between the P and one of the phenyl rings to form fused P heterocycles. The newly formed phosphines can be removed from the tungsten complex by photolysis in the presence of bis(diphenylphosphino)ethane.

Full text of DOI:10.1021/acs.organomet.6b00348

Article
pubs.acs.org/Organometallics
Phosphorus−Carbon Bond Forming Reactions of
Diphenylphosphenium and Diphenylphosphine Triflate
Complexes of Tungsten
Arumugam Jayaraman and Brian T. Sterenberg*
Department of Chemistry and Biochemistry, University of Regina, 3737 Wascana Parkway, Regina, Saskatchewan S4S 0A2, Canada
S
* Supporting Information
ABSTRACT: The complex [W(CO)5{PClPh2}] reacts with AlCl3 to
form a mixture of the phosphenium complex [W(CO)5{PPh2}][AlCl4]
and an isocarbonyl, with GaCl3 to form [W(CO)5{PPh2}][GaCl4], and with
silver trifluoromethanesulfonate to form [W(CO)5{P(OSO2CF3)Ph2}].
All three complexes react as strong P electrophiles, undergoing electro-
philic substitution reactions with aromatic and heteroaromatic com-
pounds, alkenes, and alkynes, to form aromatic and heteroaromatic phos-
phines, allyl phosphines, and alkynyl phosphines, respectively. Alkenes
lacking cleavable γ-H atoms and internal alkynes undergo tandem
electrophilic addition/substitution reactions, adding between the P and
one of the phenyl rings to form fused P heterocycles. The newly formed
phosphines can be removed from the tungsten complex by photol-
ysis in the presence of bis(diphenylphosphino)ethane.
phosphenium complex [W(CO)5{PPh2}]+ toward unsaturated
organic substrates. Because the PPh2 unit is ubiquitous in the
phosphine ligands used in homogeneous catalysis, new methods
INTRODUCTION
■
Organophosphorus compounds, which contain direct P−C bonds,
have applications as ligands for catalysis, pesticides, and flame
retardants.1 Emerging applications include materials,2 anti-
for adding this unit to organic substrates are potentially valuable.
cancer drugs,3,4 and antibiotics.3,5 Phosphorus−carbon bond
RESULTS AND DISCUSSION
formation is an important step in the synthesis of these com-
pounds. Commonly used methods for making P−C bonds include
addition of a P nucleophile such as diphenyl phosphide to an
organic electrophile, addition of P−H across a multiple bond, and
addition of an organic nucleophile to a P electrophile.1 For the last
method, the typical P electrophile is a chlorophosphine. However,
chlorophosphines are not strong electrophiles and require strong
organic nucleophiles, typically Grignard reagents, or aryl- and
alkyllithium reagents. The electrophilicity of the phosphorus can
be enhanced via chloride abstraction, leading to a reactive phos-
phenium intermediate. This approach has been applied to the
Friedel−Crafts-like electrophilic addition of phosphine units to
aromatic substrates.6 However, although this methodology has
been known for a long time, it has not gained widespread use,
possibly because of the harsh conditions, long reaction times, and
low yields.
■
One of the most commonly used methods for the formation
of phosphenium ions is abstraction of an anionic group with a
Lewis acid.10,14 We have also previously successfully used this
route to form phosphenium ion complexes and have found AlCl3
to be an effective reagent for chloride abstraction.13,15 Here, we
examined in detail the reaction of [W(CO)5{PPh2Cl}] (1) with
AlCl3. Reaction with 1 equiv of AlCl3 led to no observable
change in the 31P NMR spectrum. However, addition of 2 equiv
or more led to the disappearance of the signal for 1 and no new
signals at room temperature. At temperatures below 0 °C, two
peaks appear at δ 429.2 and 85.7, in a 2:8 ratio. On the basis of
the chemical shift, the peak at δ 429.2 is assigned as the phos-
phenium complex [W(CO)5{PPh2}][AlCl4] (2a). The large
downfield shift in the former is also expected for the planar
PR2 ligands, which typically resonate downfield of precursor
chlorophosphines by 150−300 ppm.8 Further support for this
assignment comes from a calculated 31P chemical shift (see
Experimental Section and Supporting Information for computa-
tional methods). The second component shows an upfield shift
from the starting material, and is assigned as the isocarbonyl
complex [W(CO)4{COAlCl3}{PPh2Cl}] (3a) (Scheme 1),
One possible method for enhancing the electrophilicity of
a phosphenium unit is via coordination to an electron-poor
transition-metal complex. Although a number of phosphenium
ion complexes have been described7,8 and have been shown to
be electrophilic at P,9−11 the application of these complexes
to P−C bond formation has received little attention.8,10,11
We have previously shown that the electrophilicity of metal-
coordinated phosphenium units can be exploited in P−C bond-
forming reactions with a range of unsaturated organic fragments.12,13
In this paper, we examine in detail the reactivity of the diphenyl
Received: April 28, 2016
© XXXX American Chemical Society
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a
clearly indicate that GaCl3 does not interact with a carbonyl
oxygen, driving the equilibrium further toward the phosphe-
nium ion [W(CO)5{PPh2}][GaCl4] (2b). DFT free energies,
calculated using B3LYP/LANL2TZ(f)/6-311G+(2d,p)//
B3LYP/LANL2DZ/6-31G(d,p) model chemistry, show that
with AlCl3 formation of phosphenium 2a and isocarbonyl 3a are
both exergonic, by 4.4 and 10.7 kcal/mol, respectively, and the
isocarbonyl is only 6.3 kcal/mol higher in energy than the
phosphenium complex 2a (Figure 1). With GaCl3 the formation
Scheme 1
Figure 1. DFT computed free energy surface for the formation of
phosphenium and isocarbonyl complexes using AlCl3 and GaCl3.
of isocarbonyl complex 3b is endergonic by 6.2 kcal/mol and the
formation of phosphenium ion 2b is exergonic by 7.0 kcal/mol,
and 3b is 13.2 kcal/mol higher in energy than 2b, supporting our
experimental observations.
The 1/GaCl3 mixture is more reactive than the 1/AlCl3
mixture. Even with only 1 equiv of GaCl3, it reacts immediately
with ferrocene to form the ferrocenyl phosphine complex 5.
The greater reactivity reflects the higher concentration of phos-
phenium 2 in this mixture that results from the lack of iso-
carbonyl formation.
a
Reagents and conditions: CH2Cl2, room temperature; (i) AlCl3
3 equiv; (ii) GaCl3 1 equiv; (iii) AgOSO2CF3 1.2 equiv, 2 h. (iv) Cp2Fe
2 equiv; (v) AlCl3 2 equiv. Abbreviations: [W] = W(CO)5, OTf =
OSO2CF3, Fc = ferrocenyl.
on the basis of a calculated chemical shift of δ 81.3. This
complex results from a reversible interaction of a carbonyl
of 1 with AlCl3. Further support for the identification of 3a as
an isocarbonyl comes from reaction of [W(CO)5{PPh3}] with
2 equiv of AlCl3, which led to a similar upfield shift of the
31P NMR resonance (δ 18.4 to δ 9.9). The coalescence of the
31P resonances for 2a and 3a shows that they are in equilibrium.
This equilibrium mixture is extremely reactive, and attempts to
crystallize them and isolate them as solids were not successful.
However, the solution prepared in situ readily reacts with a
wide range of organic substrates. For example, it rapidly under-
goes electrophilic addition to ferrocene, leading to the known
ferrocenyl phosphine complex [W(CO)5{P(C10H9Fe)Ph2}] (5),16
as previously described.13 The complete conversion of the mix-
ture to 5 is further evidence that 2a and 3a are in equilibrium.
The mixture of 1 with 1 equiv of AlCl3, which shows no spectro-
scopic evidence of the phosphenium complex, also reacts with
ferrocene, but much more slowly, requiring 48 h to go to com-
pletion. This indicates that this mixture contains some phos-
phenium complex, although the equilibrium lies far to the side of
the starting chlorophosphine complex 1 or isocarbonyl 3a.
In an attempt to avoid isocarbonyl formation, the softer
Lewis acid GaCl3 was also examined as a chloride abstracting
reagent. Like AlCl3, addition of 3 equiv of GaCl3 changed the
color of the solution from pale yellow to dark yellow. At room
temperature, only a broad signal at δ 419.8 was observed by
31P{1H} NMR spectroscopy. At −40 °C, this signal moved to
δ 429.3. Addition of 1 equiv of GaCl3 to 1 resulted in a mixture
of phosphenium ion 2b and 1 in a 1:1 ratio. These observations
Silver triflate acts as an alternative reagent for chloride
abstraction from 1. Reaction of 1 with silver triflate leads to the
phosphine triflate complex [W(CO)5{PPh2(OSO2CF3)}] (4)
(Scheme 1). Filtration to remove AgCl then leads to a chloride-
free solution of 4. The phosphine triflate 4 reacts rapidly
with ferrocene to yield 5,13 showing the same reactivity as the
1/AlCl3 and 1/GaCl3 mixtures (hereafter referred to as 2a,b).
The phosphenium complex can also be made by first forming
the triflate complex 4 and then abstracting triflate with AlCl3,
leading to [W(CO)5{PPh2}][AlCl3(OSO2CF3)] (2c). In this
case, the equilibrium lies toward the phosphenium complex,
and the 31P NMR spectrum of the solution shows a peak at
δ 426.2 at room temperature.
The rapid reaction of 2 or 4 with ferrocene suggests that the
metal-coordinated diphenylphosphenium ion is more reactive
than the metal-free phosphenium ion. To prove this, the reac-
tivity of metal-free diphenylphosphenium ion toward ferrocene
was examined under the same reaction conditions for comparison.
Addition of ferrocene to the CH2Cl2 solution of a PPh2Cl/AlCl3
mixture resulted in slow formation of protonated diphenylferro-
cenylphosphine, through successive electrophilic substitution and
protonation reactions (Scheme 2). This reaction comes to com-
pletion after 12 h at room temperature. The proton-coupled
31P NMR spectrum shows a doublet at δ 8.0 with 1JPH = 511 Hz.
The metal-free phosphine triflate [PPh2(OSO2CF3)] does not
react cleanly with ferrocene under similar conditions.
Reaction of the phosphine triflate complex 4 with triphenyl-
phosphine results in rapid displacement of triflate by the phosphine,
B
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a
Scheme 2
Scheme 4
leading to the phosphine-coordinated phosphenium complex 6
(Scheme 3). Reaction of 2a with PPh3 simply leads to re-formation
a
Scheme 3
a
Reagents and conditions: CH2Cl2, room temperature; (i) N,N-diethylani-
line 2 equiv, 15 min; (ii) anisole 10 equiv, 12 h; (iii) N,N-dimethyl-
p-toluidine 2 equiv, 30 min. Abbreviation: OTf = OSO2CF3.
in this case the reaction simply led to the known secondary
phosphine complex [W(CO)5{PHPh2}] (Scheme 4). This re-
activity can be attributed to the greater steric congestion at P in
the metal-coordinated diphenylphosphenium. Rather than
adding to the crowded ortho position, it abstracts hydride from
an N-methyl group. If the reaction is carried out in deuterated
chloroform, the iminium ion formed via hydride abstraction from
N,N-dimethyl-p-toluidine can be observed in solution. Hydride
abstraction from tertiary alkyl amines by Lewis acids to form
iminium ions is well documented.18 This reaction shows that this
methodology is very sensitive to sterics and may be limited to
less crowded positions.
Reactions of 2a or 4 with the secondary and primary amines
diphenylamine and aniline were used to test the tolerance of this
methodology for N−H bonds. Reaction of the triflate complex 4
with diphenylamine led to a mixture of two products, the
diphenylaminophosphine complex [W(CO)5{PPh2(NPh2)}] (9)
and the p-aminophenyl phosphine complex [W(CO)5{PPh2
(p-C6H4NH(Ph)}] (10), in a 6:4 ratio (Scheme 5). These two
a
Reagents and conditions: CH2Cl2, room temperature; (i) PPh3
1
equiv; (ii) Cp2Fe 2 equiv, 12 h; (iii) Bu4NCl 1 equiv. Abbreviation:
OTf = OSO2CF3.
of 1, as PPh3 consumes the AlCl3. The metal-free triphenyl-
phosphine coordinated diphenylphosphenium cation was described
by Burford et al. and is a stable and isolable compound.17 In con-
trast, compound 6 is relatively unstable. Addition of Bu4NCl to 6
similarly leads to rapid displacement of the PPh3 and re-formation
of chlorophosphine complex 1. With organic substrates, 6 reacts
much like the triflate complex 4 or the phosphenium complex 2a,
although much more slowly, with the PPh3 being displaced by the
incoming organic nucleophile. For example, addition of ferrocene
leads to the formation of 5 after 12 h at room temperature.
The weakness of the P−P bond in 6 can likely be attributed to the
increased steric crowding that results from the W(CO)5 unit.
Addition of diethylaniline to 2a or 4 leads exclusively to
the p-anilinyl phosphine complex [W(CO)5{PPh2(p-C6H4N-
(CH2CH3)2)}] (7) (Scheme 4). With both reagents, the
reaction is rapid, going to completion immediately at room
temperature. The isolated yield is 88%. The 31P{1H} NMR
spectrum of 7 shows a peak at δ 18.3, with 183W satellites and
a
Scheme 5
1JPW = 241 Hz. The phenyl region in the H NMR spectrum
1
shows the set of two doublets expected for a para-substituted
phenyl ring, as well as the peaks for N-bound ethyl groups.
Similarly, the reaction of 4 with anisole resulted in electrophilic
aromatic substitution exclusively in the para position, leading to
the anisolyl phosphine complex [W(CO)5{P(p-C6H4OCH3)-
Ph2}] (8) in 82% isolated yield, over 12 h at room temperature,
as previously described.13 The slower reaction rate with anisole
reflects its weaker activation toward electrophilic aromatic
substitution.
a
Reagents and conditions: CH2Cl2, room temperature, diphenylamine
1.1 equiv; (i) 15 min; (ii) 12 h. Abbreviations: OTf = OSO2CF3,
In an attempt to direct the reactivity to the ortho position,
compound 4 was treated with N,N-dimethyl-p-toluidine. Pre-
viously, we showed that metal-coordinated phosphirenyl
cations could be added to the position ortho to the amino
group, leading to a potential P,N bidentate ligand.12 However,
[W] = W(CO)5.
products result respectively from N−H and C−H activation by
the phosphine triflate complex. This reactivity demonstrates that,
even in the presence of N−H bonds, electrophilic aromatic
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substitution still occurs. Reaction of 2a with diphenylamine led
exclusively to the C−H activated product 10, in 78% isolated
yield. The selectivity here is attributed to the generation of HCl
under these reaction conditions, which cleaves the P−N bond.
Formation of 9 may also occur in this case but is reversed by
reaction with HCl, and 10 is the only observed product.
Reaction of 4 with the primary amine aniline led to
[W(CO)5{PPh2(NHPh)}] as the only product, with no
evidence for P−C bond formation. Reaction of 2a with aniline
led to regeneration of 1 and again no evidence of P−C bond
formation. In this case, the aniline is reacting with the AlCl4
anion, regenerating chloride ion, which combines with 2a to
re-form 1. The strong Lewis basicity of the primary amine appears
to preclude electrophilic aromatic substitution. Interaction of
AlCl3 with aniline is well documented and is known to interfere
with electrophilic aromatic substitution reactions on aniline.19
The heteroaromatic substrates thiophene, pyrrole, and indole
can also be readily introduced onto the metal-coordinated
phosphenium group. All three substrates react rapidly with 4 to
give the expected substitution products (Scheme 6). In the case
compounds have been isolated in 39% and 47% yields and fully
characterized.
Reaction with indole led to regioselective substitution in the
3-position, the expected position for electrophilic substitution
on indole (Scheme 6).20 Again, no evidence was observed for
P−N bond formation, and the 3-indolyl phosphine complex 14
is the only observed product (isolated yield 83%).
Addition of cyclohexene or cyclopentene to 4 led to the
anticipated electrophilic substitution reaction; however, only
the allyl products [W(CO)5{PPh2(C6H9)}] (15) (84% isolated
yield) and [W(CO)5{PPh2(C5H7)}] (16) (93% isolated yield)
are observed, with no evidence for vinyl products (Scheme 7).
a
Scheme 7
a
Scheme 6
a
Reagents and conditions: CH2Cl2, room temperature, 8 h; (i) cyclo-
hexene 10 equiv; (ii) cyclopentene 10 equiv. Abbreviation: OTf =
OSO2CF3.
a
The phosphenium ion complex 2a generated using AlCl3 reacts
with cyclohexene and cyclopentene to form the same allyl
products. Similar γ proton eliminations are also commonly
observed in Friedel−Crafts acylation of alkenes.21 Mechanisti-
cally, this reaction likely occurs via a direct γ deprotonation of
the carbocation intermediate or by addition−elimination
(Scheme 7). In an attempt to explain the regioselectivities,
DFT optimizations of the two possible intermediates were
carried out. We were unable to optimize the carbocation, but
the triflate was successfully optimized. Charges in this
intermediate (NBO charges: Cα = −0.525, Cγ = −0.407; see
the Supporting Information for the optimized structure) show
that the (OC)5W{PPh2} unit has a significant +I effect, ren-
dering the α-H atom less acidic than the γ-H atoms and
favoring γ deprotonation and allyl formation.
Next, in an attempt to generate a vinyl phosphine,
norbornene was added to compound 4. Proton loss from the
γ position in norbornene would lead to an unfavorable bridge-
head double bond; thus we anticipated that, in this case, the
α proton would be lost, leading to a vinyl phosphine. However,
the observed product [W(CO)5{PPh(C6H4C7H10)}] (17),
isolated in 77% yield, is instead the result of tandem electro-
philic addition reactions, in which the intermediate formed by
electrophilic addition to the alkene carries out an electrophilic
attack on the adjacent phenyl ring (Scheme 8), leading to a
Reagents and conditions: CH2Cl2, room temperature, 15 min;
(i) thiophene 3 equiv; (ii) pyrrole 4 equiv; (iii) indole 2 equiv.
Abbreviation: OTf = OSO2CF3.
of thiophene, the only observed product, [W(CO)5{PPh2
(2-C4H3S)}] (11), results from substitution at the 2-position,
which is expected to be the most reactive toward electrophilic
substitution.20 The 31P{1H} NMR spectrum of 11 gives a
singlet with 183W satellites at δ 7.7 (1JPW = 247 Hz), while the
1H NMR spectrum shows three thienyl peaks at δ 7.68, 7.36,
and 7.21, in addition to phenyl peaks, and the isolated yield is
72%.
The reaction of 4 with pyrrole led to a 1:1 mixture of
two isomers [W(CO)5{PPh2(2-C4H3NH)}] (12) and
[W(CO)5{PPh2(3-C4H3NH)}] (13), in which the phosphe-
nium unit added to the 2- or 3-position of pyrrole, respectively
(Scheme 6). This reaction is very rapid, and carrying out
the same reaction at −80 °C did not alter the regioselectivity.
There is no evidence for P−N bond formation. The poor selec-
tivity in pyrrole in comparison to thiophene is likely a con-
sequence of the greater activation of pyrrole toward electro-
philic substitution,20 which results in rapid kinetics and no
differentiation between two possible intermediates. Sepa-
ration of the two isomers is straightforward, and both
D
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charge22 in the P-substituted norbornyl cation intermediate
(Scheme 8).
a
Scheme 8
Addition of the terminal alkyne phenylacetylene to 2a or 4
results in an electrophilic substitution reaction of the termi-
nal H atom, leading to the known phenylalkynyl phosphine
complex 18 in 79% isolated yield (Scheme 9).23 In contrast to
a
Scheme 9
a
Reagents and conditions: CH2Cl2, room temperature, norbornene
5 equiv, 1 h. Abbreviation: OTf = OSO2CF3.
a
Reagents and conditions: CH2Cl2, room temperature; (i) phenyl-
acetylene 2 equiv, 10 min; (ii) diphenylacetylene 2.5 equiv, 30 min.
Abbreviation: OTf = OSO2CF3.
novel six-membered P heterocycle, fused to both phenyl and
norbornyl rings. The X-ray crystal structure of the product
(Figure 2) shows that the P is bound to C7 of the norbornyl
the reactions with alkenes, with phenylacetylene, elimination of
the α proton is favored and rapid. Reaction of 2a or 4 with
diphenylacetylene results in an intermediate without an acidic
proton and leads to a tandem electrophilic reaction, in which
the intermediate attacks an adjacent phenyl ring, leading to the
1,2,3-triphenylbenzophosphole complex 19 in 58% isolated
yield (Scheme 9). Compound 19 was completely characterized,
including by X-ray crystallography (Figure 3). This reaction is
Figure 2. ORTEP diagram showing the molecular structure of 17.
Thermal ellipsoids are shown at the 50% level, and H atoms have been
omitted. Selected distances (Å) and angles (deg): W(1)−P(1) =
2.5367(4), P(1)−C(7) = 1.844(2), P(1)−C(8) = 1.821(2), C(1)−
C(2) = 1.542(2), C(2)−C(3) = 1.565(2), C(3)−C(4) = 1.540(2),
C(4)−C(5) = 1.541(2), C(5)−C(6) = 1.550(3), C(6)−C(1) =
1.539(3), C(1)−C(7) = 1.548(2), C(7)−C(4) = 1.539(2), C(2)−
C(9) = 1.507(3), C(8)−C(9) = 1.400(2); C(8)−P(1)−C(7) =
102.88(8), C(1)−C(7)−P(1) = 114.0(1), C(2)−C(1)−C(7) =
100.4(1), C(9)−C(2)−C(1) = 110.8(1), C(8)−C(9)−C(2) =
120.7(1), C(9)−C(8)−P(1) = 120.7(1).
Figure 3. ORTEP diagram showing the molecular structure of 19.
Thermal ellipsoids are shown at the 50% level, and H atoms have been
omitted for clarity. Selected distances (Å) and angles (deg): W(1)−
P(1) = 2.5141(7), P(1)−C(9) = 1.817(3), C(9)−C(8) = 1.406(4),
C(8)−C(7) = 1.474(4), C(6)−C(7) = 1.362(4), P(1)−C(6) = 1.823(3);
C(9)−P(1)−C(6) = 91.3(1), C(9)−C(8)−C(7) = 113.9(2), C(6)−
C(7)−C(8) = 114.1(2), C(7)−C(6)−P(1) = 110.8(2).
group, while the phenyl ring is bound to C2. Assignment of the
13C{1H} NMR spectrum was used to confirm that the bulk
sample was the same as the X-ray crystal. Simple addition across
the alkene would lead to C2−C3 substitution for the P and
aryl group. The observed regioselectivity can be rationalized
by considering the nonclassical delocalization of the positive
similar to that described above in the reaction with norbornene
and is also reminiscent of the route to benzophospholes
described by Mathey et al.24 in which phosphinidene complexes
are used to activate aryl C−H bonds, although here P−C and
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CDCl3, CD2Cl2 or C6D6. IR spectra were recorded on a Digilab FTIR
instrument in CH2Cl2 solution. Elemental analyses were carried out
by the Analytical and Instrumentation Laboratory in the Department of
Chemistry at the University of Alberta. Compounds 1, 5, and 8 were
synthesized as described previously.13
C−C bonds are formed sequentially in the same reaction, and
the ring-closing reaction is a C−C bond formation. Metal-free
1,2,3-triphenylbenzophosphole was also previously prepared by
oxidative cyclization of diphenylacetylene and diphenylene-
phosphine oxide, followed by reduction with HSiCl3.25 In con-
trast to the reactions described here, reactions of metal-free
phosphenium ions with alkynes lead to phosphirenium rings.26
Application of the methodology described here to phosphine
synthesis requires a means of removing the phosphine from
the metal after the reaction. The novel fused-ring phosphine
complex [W(CO)5{PPh(C6H4C7H10)}] (17) was chosen to
illustrate the methodology. Photolysis of a THF solution
containing 17 and dppe readily afforded the targeted free
phosphine 20 in 81% yield (Scheme 10). The 31P{1H} NMR
Reaction of [W(CO)5{PPh2Cl}] (1) with AlCl3. Compounds
[W(CO)5{PPh2Cl}] (1; 20 mg, 0.037 mmol) and AlCl3 (14.7 mg,
0.110 mmol) were dissolved in CD2Cl2 (0.5 mL), resulting in the imme-
diate formation of a dark yellow solution. 31P{1H} NMR (−40 °C):
1
1
δ 429.2 (s, JPW = 353 Hz, 2a) and 85.7 (s, JPW = 215 Hz, 3a). Note:
There was no apparent reaction when 1 equiv of AlCl3 was added to 1.
Reaction of [W(CO)5{PPh2Cl}] (1) with GaCl3. Compounds
[W(CO)5{PPh2Cl}] (1; 25 mg, 0.046 mmol) and GaCl3 (8.1 mg,
0.046 mmol) were dissolved in CD2Cl2 (0.5 mL), resulting in the
immediate formation of a dark yellow solution. 31P{1H} NMR (CD2Cl2,
−80 °C): δ 431.1 (s, 2b) and 96.6 (s, 1) in a 1:1 ratio. Compounds 1
(25 mg, 0.046 mmol) and GaCl3 (24.3 mg, 0.138 mmol) dissolved in
CD2Cl2 (0.5 mL) showed only the signal for 2b at room temperature
a
Scheme 10
1
and −40 °C (δ 429.3 (s, JPW = 353 Hz).
[W(CO)5{PPh2(OSO2CF3)}] (4).
The compounds [W(CO)5{PPh2Cl}] (1; 25 mg, 0.046 mmol) and
AgOSO2CF3 (14.2 mg, 0.055 mmol) were dissolved in CH2Cl2
(2 mL). This solution was stirred for 2 h, resulting in a yellow
solution and a white precipitate. The solution was filtered through
Celite. Conversion is quantitative by NMR spectroscopy. This air- and
moisture-sensitive solution is stable for days at −20 °C or hours at
room temperature. This reaction was also carried out in CDCl3 for
NMR spectroscopy. IR (νCO, CH2Cl2, cm−1): 2076 (w), 1941 (vs).
a
Reagents and conditions: THF, room temperature, dppe 1.2 equiv,
photolysis, 2.5 h.
spectrum of 20 shows a singlet with no W satellites at δ −29.9,
and the 1H NMR spectrum shows signals and splitting patterns
similar to those of the metal complex. This methodology is a
modification of the method described by Mathey et al., where
tungsten phosphine complexes were heated with dppe to remove
monodentate phosphines or phospholes.24,27 The photolysis
methodology has the advantages of being faster and cleaner than
the method involving heat.
1
31P{1H} NMR (CDCl3): δ 167.4 (s, JPW = 308 Hz). 19F NMR
1
(CDCl3): δ −76.4 (s, OSO2CF3). H NMR (CDCl3): δ 7.56−7.70
1
(m, Ph). 13C{1H} NMR (CDCl3): δ 118.4 (q, JCF = 319 Hz,
3
2
OSO2CF3), 129.2 (d, JCP = 11 Hz, Ph), 131.6 (d, JCP = 15 Hz, Ph),
4
1
133.1 (d, JCP = 2 Hz, Ph), 137.0 (d, JCP = 39 Hz, ipso-Ph), 194.7 (d,
2JCP = 8 Hz, 1JCW = 126 Hz, cis-CO), 197.6 (d, 2JCP = 33 Hz, trans-CO).
[W(CO)5{PPh2(PPh3)}][OSO2CF3] (6).
A solution of
CONCLUSIONS
■
[W(CO)5{PPh2(OSO2CF3)}] (4) was prepared from [W(CO)5{PPh2Cl}]
(1; 90.0 mg, 0.166 mmol) and AgOSO2CF3 (51 mg, 0.199 mmol) in
CH2Cl2 (5 mL) as described above. PPh3 (43.4 mg, 0.166 mmol)
was then added, resulting in a color change to yellow. Crystals of
[W(CO)5{PPh2(PPh3)}][OSO2CF3]·CH2Cl2 (6·CH2Cl2) were grown
by cooling the saturated pentane/CH2Cl2 solution to −20 °C. Com-
pound 6·CH2Cl2 is crystalline; however, under reduced pressure it
gradually reverts back to the triflate phosphine 4. Yield: 143 mg, 86%.
IR (νCO, CH2Cl2, cm−1): 2074 (w), 1941 (vs). 31P{1H} NMR
The phosphenium and phosphine triflate metal complexes 2 and 4
are versatile reagents for the formation of P−C bonds and undergo
electrophilic addition reactions with a range of unsaturated organic
substrates, including aromatics, heteroaromatics, alkenes, and
alkynes. The reactions are much faster than those of metal-free
phosphenium ions, and in some cases the reactivity is unique as a
result of the protection of the P lone pair. The methodologies
described here are useful for the formation of diphenylphosphines
with aryl, heteroaryl, alkynyl, and allyl groups in the third position.
They can also be used to form P heterocycles through tandem
electrophilic addition reactions involving one of the phenyl sub-
stituents.
1
1
(CDCl3): δ 12.1 (d, JPP = 216 Hz, PPh3), 41.8 (d, JPP = 216 Hz, d,
1JPW = 262 Hz, PPPh3). Anal. Calcd for [W(CO)5{PPh2(PPh3)}]-
[OSO2CF3]·CH2Cl2: C, 44.20; H, 2.71; S, 3.19. Found: C, 44.20, H,
2.73; S, 3.14.
Reaction of [W(CO)5{PPh2(PPh3)}][OSO2CF3] (6) with NBu4Cl.
Compound 6 (20.0 mg, 0.022 mmol) was dissolved in CH2Cl2
(1 mL), and to this solution was added solid NBu4Cl (6.7 mg,
0.024 mmol). After the addition of NBu4Cl, the solution immediately
turned pale yellow from yellow, and the spectra showed complete
reversion to [W(CO)5{PPh2Cl}] (1) and PPh3. 31P{1H} NMR (CH2Cl2):
EXPERIMENTAL SECTION
■
General Comments. All procedures except flash chromatography
were carried out using standard Schlenk techniques or in a glovebox
under a nitrogen atmosphere. Diethyl ether, pentane, and THF were
distilled from Na/benzophenone. Dichloromethane was purified using
solvent purification columns containing alumina, followed by vacuum
distillation from P2O5. CDCl3 was vacuum-distilled from P2O5. CD2Cl2
and C6D6 were used as received. Solvents for flash chromatography were
not purified. Aluminum chloride was purified by sublimation and stored
under an inert atmosphere. Photolysis reactions were carried out in
Pyrex vessels using a Rayonet photochemical reactor equipped with nine
lamps having a maximum output at 260 nm. The NMR spectra were
recorded on a Varian Mercury 300 spectrometer at 300.177 MHz (1H),
121.514 MHz (31P), 75.479 MHz (13C{1H}), or 282.231 MHz (19F) in
1
δ 93.6 (s, JPW = 283 Hz), −6.6 (s, PPh3).
Reaction of [W(CO)5{PPh2(PPh3)}][OSO2CF3] (6) with Ferro-
cene. Compound 6 (35.0 mg, 0.038 mmol) was dissolved in CH2Cl2
(2 mL), and to the resulting solution was added solid ferrocene
(14.1 mg, 0.076 mmol); this mixture was then stirred for 12 h at room
temperature, resulting in a color change to brown. The spectrum
showed complete conversion to [W(CO)5{P(C10H9Fe)Ph2}] (5)
and [HPPh3][OSO2CF3]. 31P{1H} NMR (CH2Cl2): δ 9.4 (s, com-
pound 5), 1.5 (br s, [HPPh3][OSO2CF3]).
F
DOI: 10.1021/acs.organomet.6b00348
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
3
[W(CO)5{PPh2(p-C6H4N(CH2CH3)2)}] (7).
(br s, 1H, NH), 7.03−7.06 (m, 3H, N-bound Ph), 7.16 (dd, 2H, JHH
4
= 7.2 Hz, JHH = 0.9 Hz, -C6H4NH(Ph)), 7.30−7.51 (m, 14H, 2H of
−C6H4NH(Ph), 2H of N-bound Ph, 10H of P-bound Ph). 13C{1H}
3
NMR (CDCl3): δ 115.7 (d, JCP = 11 Hz, −C6H4NH(Ph)), 120.4 (s,
1
N-bound Ph), 123.2 (s, N-bound Ph), 124.1 (d, JCP = 47 Hz, ipso-
3
C6H4NH(Ph), 128.8 (d, JCP = 10 Hz, P-bound Ph), 129.7 (s,
N-bound Ph), 130.3 (d, JCP = 2 Hz, P-bound Ph), 132.9 (d, JCP
11 Hz, P-bound Ph), 135.2 (d, JCP = 14 Hz, −C6H4NH(Ph), 136.4
(d, JCP = 41 Hz, P-bound ipso-Ph), 141.2 (s, N-bound ipso-Ph), 146.1
(s, d, ipso−C6H4NH(Ph)), 197.7 (d, JCP = 7 Hz, JCW = 126 Hz, cis-
CO), 199.7 (d, JCP = 21 Hz, trans-CO). Anal. Calcd for
C29H20NO5PW: C, 51.43; H, 2.98; N, 2.07. Found: C, 51.59, H, 2.99;
4
2
=
2
1
A solution of [W(CO)5{PPh2(OSO2CF3)}] (4) was prepared from
[W(CO)5{PPh2Cl}] (1; 80.0 mg, 0.147 mmol) and AgOSO2CF3
(45.4 mg, 0.177 mmol) in CH2Cl2 (4 mL) as described above.
N,N-Diethylaniline (47 μL, 0.294 mmol) was then added, resulting in
a color change to yellow. The solvent was removed under reduced
pressure, and the residue was purified by flash chromatography
(alumina, 10/90 v/v diethyl ether/petroleum ether). The yellow
product was crystallized by diffusion of pentane into a dichloro-
methane solution at −20 °C. Yield: 85 mg, 88%. IR (νCO, CH2Cl2,
2
1
2
N, 2.13.
Reaction of [W(CO)5{PPh2Cl}] (1) with Diphenylamine and
AlCl3. The compound [W(CO)5{PPh2Cl}] (1; 80 mg, 0.147 mmol)
and AlCl3 (39.3 mg, 0.294 mmol) were dissolved in CH2Cl2 (4 mL).
This solution was stirred for 5 min, resulting in a yellow solution.
Diphenylamine (27.4 mg, 0.162 mmol) was added, and the solution
was stirred for 12 h at room temperature, resulting in a color change to
dark yellow. The 31P NMR spectrum of the reaction solution shows
that 10 is the major product and that 9 is not formed. The solvent was
removed under reduced pressure, and compound 10 was purified by
flash chromatography (alumina, 10/90 v/v diethyl ether/petroleum
ether). Yield: 78 mg, 78%.
cm−1): 2071 (w), 1937 (vs). 31P{1H} NMR (CDCl3): δ 18.3 (s, 1JPW
=
241 Hz). 1H NMR (CDCl3): δ 1.19 (t, 6H, JHH = 6.9 Hz,
3
3
NCH2CH3), 3.39 (q, 4H, JHH = 7.2 Hz, NCH2CH3), 6.68 (d, 2H,
3JHH = 9.0 Hz, arene CH), 7.32 (dd, 2H, 3JHH = 9.0 Hz, 3JHP = 10.5 Hz,
arene CH), 7.42 (m, 10H, Ph). 13C{1H} NMR (CDCl3): δ 12.8
(s, NCH2CH3), 44.5 (s, NCH2CH3), 111.2 (d, 3JCP = 11 Hz, arene C),
117.3 (d, 1JCP = 50. Hz, ipso-arene P-bound C), 128.6 (d, 3JCP = 10 Hz,
4
2
Reaction of [W(CO)5{PPh2(OSO2CF3)}] (4) with N,N-Dimethyl-
Ph), 130.0 (d, JCP = 2 Hz, Ph), 132.8 (d, JCP = 12 Hz, Ph), 135.5
2
1
p-toluidine.
(d, JCP = 14 Hz, arene C), 137.2 (d, JCP = 42 Hz, ipso-Ph), 149.3
(s, ipso-arene N-bound C), 197.8 (d, JCP = 7 Hz, JCW = 126 Hz,
cis-CO), 200.0 (d, JCP = 21 Hz, JCW = 145 Hz, trans-CO). Anal.
Calcd for C27H24NO5PW: C, 49.34; H, 3.68; N, 2.13. Found: C, 49.22,
H, 3.69; N, 2.16.
2
1
2
1
Reaction of [W(CO)5{PPh2(OSO2CF3)}] (4) with Diphenyl-
amine. A solution of [W(CO)5{PPh2(OSO2CF3)}] (4) was prepared
from [W(CO)5{PPh2Cl}] (1; 150 mg, 0.276 mmol) and AgOSO2CF3
(85 mg, 0.331 mmol) in CH2Cl2 (8 mL) as described above. Diphe-
nylamine (51.4 mg, 0.304 mmol) was then added, resulting in a color
change to yellow. The solvent was removed under reduced pressure, and
the residue was purified by flash chromatography (alumina, 10/90 v/v
diethyl ether/petroleum ether). Two fractions were collected separately,
and the solvent was evaporated under reduced pressure. The first frac-
tion was obtained as yellow crystals and identified as the P−N-bound
product 9. The second fraction was obtained as pale yellow crystals and
identified as the P−C bound product 10.
A solution of [W(CO)5{PPh2(OSO2CF3)}] (4) was prepared from
[W(CO)5{PPh2Cl)}] (1; 80.0 mg, 0.147 mmol) and AgOSO2CF3
(48.7 mg, 0.191 mmol) in CH2Cl2 (4 mL) as described above.
N,N-Dimethyl-p-toluidine (43 μL, 0.294 mmol) was added, and the
solution was stirred for 30 min, resulting in a color change to yellow.
The solvent was removed under reduced pressure, and the residue was
purified by flash chromatography (alumina, 10/90 v/v diethyl ether/
petroleum ether) and crystallized as colorless crystals by cooling a
saturated pentane/CH2Cl2 solution to −20 °C, yielding crystals of the
known compound [W(CO)5{PHPh2}]. Yield: 67 mg, 89%. 31P NMR
1
1
1
(CDCl3): δ −12.5 (dm, JPW = 230 Hz, JPH = 346 Hz). H NMR
(CDCl3): δ 6.84 (d, 1H, 1JHP = 345 Hz, PH), 7.41−7.60 (m, 10H, Ph).
These spectroscopic data match previously published data.28
[W(CO)5{PPh2(2-C4H3S)}] (11).
Characterization of [W(CO)5{PPh2(NPh2)}] (9).
Yield: 93 mg, 50%. IR (νCO, CH2Cl2, cm−1): 2072 (w), 1942 (vs).
1
31P{1H} NMR (CDCl3): δ 77.3 (s, JPW = 274 Hz). 1H NMR
(CDCl3): δ 7.02−7.07 (m, 6H, Ph), 7.12−7.18 (m, 4H, Ph), 7.36−
7.44 (m, 6H, Ph), 7.67−7.73 (m, 4H, Ph). 13C{1H} NMR (CDCl3): δ
A solution of [W(CO)5{PPh2(OSO2CF3)}] (4) was prepared from
[W(CO)5{PPh2Cl}] (1; 90.0 mg, 0.166 mmol) and AgOSO2CF3
(51.1 mg, 0.199 mmol) in CH2Cl2 (5 mL) as described above. Thio-
phene (40 μL, 0.497 mmol) was added, resulting in a color change to
red. The solvent was removed under reduced pressure, and the residue
was purified by flash chromatography (silica, 20/80 v/v diethyl ether/
petroleum ether). The yellow product was crystallized by slow dif-
fusion of pentane into a saturated CH2Cl2 solution at −20 °C. Yield:
71 mg, 72%. IR (νCO, CH2Cl2, cm−1): 2073 (w), 1946 (vs). 31P{1H}
125.3 (s, N-bound Ph), 128.2 (d, 3JCP = 3 Hz, N-bound Ph), 128.5 (d,
4
3JCP = 10 Hz, P-bound Ph), 129.3 (s, N-bound Ph), 130.4 (d, JCP
=
2
2 Hz, P-bound Ph), 132.4 (d, JCP = 13 Hz, P-bound Ph), 137.8 (d,
1JCP = 42 Hz, P-bound ipso-Ph), 146.3 (d, JCP = 5 Hz, N-bound ipso-
2
2
1
2
Ph), 197.1 (d, JCP = 7 Hz, JCW = 127 Hz, cis-CO), 199.5 (d, JCP
=
26 Hz, trans-CO). Anal. Calcd for C29H20NO5PW: C, 51.43; H, 2.98;
N, 2.07. Found: C, 51.47, H, 2.98; N, 2.12.
Characterization of [W(CO)5{PPh2(p-C6H4NH(Ph)}] (10).
1
1
NMR (CDCl3): δ 7.7 (s, JPW = 247 Hz). H NMR (CDCl3): δ 7.21
(m, 1H, C4H3S), 7.36 (m, 1H, C4H3S), 7.43−7.50 (m, 10H, Ph), 7.68
(m, 1H, C4H3S). 13C{1H} NMR (CDCl3): δ 128.6 (s, C4H3S), 128.8
3
4
2
(d, JCP = 10 Hz, Ph), 130.7 (d, JCP = 2 Hz, Ph), 132.4 (d, JCP
=
3
1
13 Hz, Ph), 133.5 (d, JCP = 3 Hz, C4H3S), 136.5 (d, JCP = 44 Hz,
ipso-Ph), 137.5 (d, 2JCP = 11 Hz, C4H3S), 137.8 (d, 1JCP = 39 Hz, ipso-
C4H3S),197.3 (d, 2JCP = 7 Hz, 1JCW = 126 Hz, cis-CO), 199.2 (d, 2JCP
=
Yield: 62 mg, 33%. IR (νCO, CH2Cl2, cm−1): 2071 (w), 1937 (vs). 31P{1H}
22 Hz, trans-CO). Anal. Calcd for C21H13O5PSW: C, 42.59; H, 2.21;
S, 5.41. Found: C, 42.42; H, 2.31; S, 5.46.
1
1
NMR (CDCl3): δ 19.7 (s, JPW = 243 Hz). H NMR (CDCl3): δ 5.92
G
DOI: 10.1021/acs.organomet.6b00348
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
Reaction of [W(CO)5{PPh2(OSO2CF3)}] (4) with Pyrrole. A
solution of [W(CO)5{PPh2(OSO2CF3)}] (4) was prepared from
[W(CO)5{PPh2Cl}] (1; 200 mg, 0.368 mmol) and AgOSO2CF3
(113 mg, 0.442 mmol) in CH2Cl2 (8 mL) as described above. Pyrrole
(102 μL, 1.472 mmol) was then added, resulting in a color change to
brown. The solvent was removed under reduced pressure, and the
residue was purified by flash chromatography (silica, 10/90 v/v diethyl
ether/petroleum ether). Two fractions were collected separately, and
the solvent was evaporated under reduced pressure. Both fractions
were obtained as pale yellow powders. The first fraction was identified
as the C2-substituted isomer [W(CO)5{PPh2(2-C4H3NH)}] (12) and
the second fraction as the C3-substituted isomer [W(CO)5{PPh2
(3-C4H3NH)}] (13).
1H NMR (CDCl3): δ 6.95 (m, 2H, C8H5NH), 7.21 (m, 1H,
C8H5NH), 7.37−7.46 (m, 7H, 1H of C8H5NH and 6H of Ph), 7.56−
7.62 (m, 4H, Ph), 7.69 (m, 1H, C8H5NH), 8.60 (br s, 1H, C8H5NH).
13C{1H} NMR (CDCl3): δ 107.5 (d, 1JCP = 57 Hz, C3), 112.1 (s, C7),
121.1 (s, C4), 122.1 (s, C6), 123.4 (s, C5), 127.8 (d, 2JCP = 3 Hz, C3a),
128.7 (d, 3JCP = 10 Hz, Ph), 130.1 (d, 4JCP = 2 Hz, Ph), 132.3 (d, 2JCP
= 12 Hz, Ph), 135.2 (d, 2JCP = 25 Hz, C2), 135.7 (d, 1JCP = 39 Hz, ipso-
Ph), 138.0 (d, JCP = 7 Hz, C7a), 197.9 (d, 2JCP = 7 Hz, 1JCW = 126 Hz,
cis-CO), 199.8 (d, JCP = 21 Hz, trans-CO). Anal. Calcd for
C25H16NO5PW: C, 48.03; H, 2.58; N, 2.24. Found: C, 48.02, H, 2.21;
N, 2.23.
[W(CO)5{PPh2(C6H9)}] (15).
2
Characterization of [W(CO)5{PPh2(2-C4H3NH)}] (12).
A solution of [W(CO)5{PPh2(OSO2CF3)}] (4) was prepared from
[W(CO)5{PPh2Cl}] (1; 80.0 mg, 0.147 mmol) and AgOSO2CF3
(45.4 mg, 0.177 mmol) in CH2Cl2 (5 mL) as described above.
Cyclohexene (149 μL, 1.472 mmol) was then added, and the solution
was stirred at room temperature for 8 h, resulting in a color change to
yellow from pale yellow. The solvent was removed under reduced
pressure, and the residue was purified by flash chromatography (silica,
10/90 v/v diethyl ether/petroleum ether). The pale yellow crystals of
[W(CO)5{PPh2(C6H9)}] (15) were obtained by cooling a saturated
pentane solution to −20 °C. Yield: 73 mg, 84%. IR (νCO, CH2Cl2,
Yield: 83 mg, 39%. IR (νCO, CH2Cl2, cm−1): 2072 (w), 1939 (vs).
31P{1H} NMR (CDCl3): δ 0.2 (s, 1JPW = 244 Hz). 1H NMR (CDCl3):
δ 6.39 (m, 1H, C4H3NH), 6.81 (m, 1H, C4H3NH), 7.04 (m, 1H,
C4H3NH), 7.35−7.48 (m, 10H, Ph), 7.98 (br s, 1H, NH). 13C{1H}
NMR (CDCl3): δ 110.9 (d, 3JCP = 10 Hz, C4H3NH), 122.1 (d, 2JCP
=
1
18 Hz, C4H3NH), 122.6 (d, JCP = 54 Hz, ipso-C4H3NH), 124.3 (d,
3
4
3JCP = 4 Hz, C4H3NH), 129.0 (d, JCP = 10 Hz, Ph), 130.6 (d, JCP
=
2 Hz, Ph), 132.1 (d, 2JCP = 12 Hz, Ph), 135.8 (d, 1JCP = 44 Hz, ipso-Ph),
197.3 (d, JCP = 7 Hz, JCW = 126.1 Hz, cis-CO), 199.3 (d, JCP
21 Hz, JCW = 143 Hz, trans-CO). Anal. Calcd for C21H14NO5PW:
C, 43.85; H, 2.45; N, 2.44. Found: C, 43.63, H, 2.51; N, 2.48.
Characterization of [W(CO)5{PPh2(3-C4H3NH)}] (13).
2
1
2
cm−1): 2070 (w), 1936 (vs). 31P{1H} NMR (CDCl3): δ 24.1 (s, 1JPW
=
=
1
1
241 Hz). H NMR (CDCl3): δ 1.27−1.78 (m, 4H, C6H9), 1.94−2.05
(m, 2H, C6H9), 3.42 (m, 1H, C6H9), 5.83 (m, 2H, C6H9), 7.35−7.47
(m, 8H, Ph), 7.61−7.70 (m, 2H, Ph). 13C{1H} NMR (CDCl3): δ 22.3
2
4
3
(d, JCP = 11 Hz, C6H9), 25.0 (d, JCP = 2 Hz, C6H9), 25.3 (d, JCP
=
1
3
5 Hz, C6H9), 38.2 (d, JCP = 24 Hz, C6H9), 124.4 (d, JCP = 4 Hz,
C6H9), 128.5 (d, 3JCP = 10 Hz, Ph), 128.9 (d, JCP = 9 Hz, Ph), 129.9
3
4
4
2
(d, JCP = 2 Hz, Ph), 130.8 (d, JCP = 2 Hz, Ph), 131.9 (d, JCP
=
1
2
10 Hz, Ph), 132.5 (d, JCP = 47 Hz, ipso-Ph), 132.7 (d, JCP = 8 Hz,
2
1
C6H9), 134.5 (d, JCP = 11 Hz, Ph), 136.5 (d, JCP = 38 Hz, ipso-Ph),
197.4 (d, 2JCP = 7 Hz, 1JCW = 126 Hz, cis-CO), 199.5 (d, 2JCP = 22.0 Hz,
trans-CO). Anal. Calcd. for C23H19O5PW: C, 46.81; H, 3.24. Found:
C, 46.68; H, 3.27.
Yield: 99 mg, 47%. IR (νCO, CH2Cl2, cm−1): 2070 (w), 1936 (vs).
1
31P{1H} NMR (CDCl3): δ - 0.4 (s, JPW = 240 Hz). 1H NMR
(CDCl3): δ 6.22 (m, 1H, C4H3NH), 6.94 (m, 2H, C4H3NH), 7.36−
[W(CO)5{PPh2(C5H7)}] (16).
7.52 (m, 10H, Ph), 8.54 (br s, 1H, NH). 13C{1H} NMR (CDCl3):
2
1
δ 113.5 (d, JCP = 9 Hz, C4H3NH), 115.7 (d, JCP = 59 Hz, ipso-
C4H3NH), 120.5 (d, 3JCP = 10 Hz, C4H3NH), 126.4 (d, 2JCP = 24 Hz,
3
4
C4H3NH), 128.6 (d, JCP = 10 Hz, Ph), 130.0 (d, JCP = 2 Hz, Ph),
2
1
132.4 (d, JCP = 12 Hz, Ph), 137.4 (d, JCP = 45 Hz, ipso-Ph), 197.8
(d, 2JCP = 7 Hz, 1JCW = 126 Hz, cis-CO), 200.0 (d, 2JCP = 20 Hz, 1JCW
=
144 Hz, trans-CO). Anal. Calcd for C21H14NO5PW: C, 43.85; H, 2.45;
N, 2.44. Found: C, 43.76, H, 2.50; N, 2.45.
[W(CO)5{P(3-C8H5NH)Ph2}] (14).
A solution of [W(CO)5{PPh2(OSO2CF3)}] (4) was prepared from
[W(CO)5{PPh2Cl}] (1; 95.0 mg, 0.175 mmol) and AgOSO2CF3
(53.9 mg, 0.210 mmol) in CH2Cl2 (5 mL) as described above.
Cyclopentene (160 μL, 1.758 mmol) was then added, and the solution
was stirred at room temperature for 8 h, resulting in a color change to
yellow from pale yellow. The solvent was removed under reduced
pressure, and the residue was purified by flash chromatography (silica,
10/90 v/v diethyl ether/petroleum ether). Pale yellow crystals of
[W(CO)5{PPh2(C5H7)}] (16) were obtained by cooling a saturated
pentane solution to −20 °C. Yield: 94 mg, 93%. IR (νCO, CH2Cl2, cm−1):
2070 (w), 1935 (vs). 31P{1H} NMR (CDCl3): δ 22.0 (s, 1JPW = 240 Hz).
1H NMR (CDCl3): δ 1.54 (m, 1H, C5H7), 1.95 (m, 1H, C5H7), 2.16 (m,
1H, C5H7), 2.32 (m, 1H, C5H7), 3.96 (m, 1H, C5H7), 5.80 (m, 2H,
C5H7), 7.38−7.52 (m, 8H, Ph), 7.56−7.65 (m, 2H, Ph). 13C{1H} NMR
(CDCl3): δ 26.5 (d, 2JCP = 3 Hz, C5H7), 32.3 (d, 3JCP = 1 Hz, C5H7), 48.8
A solution of [W(CO)5{PPh2(OSO2CF3)}] (4) was prepared from
[W(CO)5{PPh2Cl}] (1; 120.0 mg, 0.221 mmol) and AgOSO2CF3
(73.7 mg, 0.265 mmol) in CH2Cl2 (5 mL) as described above. A solu-
tion of indole (51.7 mg, 0.442 mmol) in CH2Cl2 (5 mL) was added,
and the mixture was stirred at room temperature for 15 min, resulting
in a color change to orange. The solvent was removed under reduced
pressure, and the residue was purified by flash chromatography
(alumina, 20/80 v/v diethyl ether/petroleum ether). The white product
was crystallized by slow diffusion of pentane into a saturated CH2Cl2
solution at −20 °C. Yield: 115 mg, 83%. IR (νCO, CH2Cl2, cm−1):
2071 (w), 1937 (vs). 31P{1H} NMR (CDCl3): δ −2.4 (s, 1JPW = 240 Hz).
(d, 1JCP = 23 Hz, C5H7), 128.2 (d, 3JCP = 4 Hz, C5H7), 128.5 (d, 3JCP
=
10 Hz, Ph), 128.7 (d, 3JCP = 9 Hz, Ph), 130.0 (d, 4JCP = 2 Hz, Ph), 130.6
(d, 4JCP = 2 Hz, Ph), 132.1 (d, 2JCP = 10 Hz, Ph), 133.5 (d, 1JCP = 38 Hz,
2
2
ipso-Ph), 134.1 (d, JCP = 11 Hz, Ph), 136.0 (d, JCP = 10 Hz, C5H7),
136.3 (d, 1JCP = 39 Hz, ipso-Ph), 197.5 (d, 2JCP = 7 Hz, 1JCW = 126 Hz,
H
DOI: 10.1021/acs.organomet.6b00348
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Article
2
1
cis-CO), 199.6 (d, JCP = 22 Hz, JCW = 143 Hz, trans-CO). Anal.
Calcd. for C22H17O5PW: C, 45.86; H, 2.97. Found: C, 46.02; H, 3.03.
[W(CO)5{PPh(C6H4C7H10)}] (17).
[W(CO)5{PPh(C6H4C(Ph)C(Ph)}] (19).
A solution of [W(CO)5{PPh2(OSO2CF3)}] (4) was prepared from
[W(CO)5{PPh2Cl}] (1; 160 mg, 0.294 mmol) and AgOSO2CF3
(91 mg, 0.353 mmol) in CH2Cl2 (8 mL) as described above.
Diphenylacetylene (131 mg, 0.736 mmol) was then added, and the
mixture was stirred for 30 min at room temperature, resulting in a
color change to brown. The solvent was removed under reduced pres-
sure, and the residue was purified by flash chromatography (silica gel,
10/90 v/v diethyl ether/petroleum ether). Yellow crystals of
[W(CO)5{PPh(C6H4C(Ph)C(Ph)}] (19) were obtained by cooling
a saturated CH2Cl2/pentane solution to −20 °C. Yield: 117 mg. 58%.
IR (νCO, CH2Cl2, cm−1): 2073 (w), 1940 (vs). 31P{1H} NMR
A solution of [W(CO)5{PPh2(OSO2CF3)}] (4) was prepared from
[W(CO)5{PPh2Cl}] (1; 140.0 mg, 0.258 mmol) and AgOSO2CF3
(79.4 mg, 0.309 mmol) in CH2Cl2 (5 mL) as described above.
Norbornene (122 mg, 1.288 mmol) was then added, and the solution
was stirred at room temperature for 1 h, resulting in a color change to
brown. The solvent was removed under reduced pressure, and the
residue was purified by flash chromatography (silica, 10/90 v/v diethyl
ether/petroleum ether). Pale yellow crystals of [W(CO)5{PPh-
(C6H4C7H10)}] (17) were obtained by cooling a saturated pentane/
CH2Cl2 solution to −20 °C. Yield: 119 mg, 77%. IR (νCO, CH2Cl2,
cm−1): 2071 (w), 1937 (vs). 31P{1H} NMR (CDCl3): δ − 4.5 (s, 1JPW
1
1
(CDCl3): δ 25.8 (s, JPW = 234 Hz). H NMR (CDCl3): δ 6.74−7.73
(m, 19H, 4H of arene, 15H of Ph). 13C{1H} NMR (CDCl3): δ 125.0
(d, JCP = 6 Hz), 128.1 (d, JCP = 2 Hz), 128.2 (d, JCP = 10 Hz), 128.4 (s),
128.5 (s), 129.0 (s), 129.4 (d, JCP = 14 Hz), 129.4 (s), 129.6 (s),
1
= 239 Hz). H NMR (CDCl3): δ 1.38−1.91 (m, 6H, C6H4C7H10),
130.0 (s), 130.0 (s), 130.7 (d, JCP = 2 Hz), 131.2 (s), 131.6 (d, JCP
=
=
=
2.07−2.13 (m, 2H, C6H4C7H10), 2.77 (d, J = 8 Hz, 1H, C6H4C7H10),
2.88 (m, 1H, C6H4C7H10), 7.15 (m, 1H, C6H4C7H10), 7.26−7.41
(m, 7H, 2H of C6H4C7H10 and 5H of Ph), 7.52−7.59 (m, 1H,
C6H4C7H10). 13C{1H} NMR (CDCl3): δ 28.7 (d, 4JCP = 9 Hz, CH2 of
C6H4C7H10), 31.2 (d, 3JCP = 13 Hz, CH2 of C6H4C7H10), 40.7 (s, CH2
of C6H4C7H10), 41.2 (d, 3JCP = 5 Hz, CH of C6H4C7H10), 41.6 (d, 2JCP
= 7 Hz, CH of C6H4C7H10), 45.9 (d, 2JCP = 3 Hz, CH of C6H4C7H10),
2 Hz), 133.0 (d, JCP = 14 Hz), 134.6 (d, JCP = 14 Hz), 135.2 (d, JCP
9 Hz), 142.1 (d, 1JCP = 48 Hz), 143.3 (d, 1JCP = 38 Hz), 145.0 (d, JCP
1
12 Hz), 147.1 (d, JCP = 10 Hz), 196.2 (d, 2JCP = 7 Hz, JCW = 125 Hz,
2
cis-CO), 198.3 (d, JCP = 21 Hz, trans-CO). Anal. Calcd. for
C31H19O5PW: C, 54.25; H, 2.79. Found: C, 53.91; H, 2.82.
{PPh(C6H4C7H10)} (20).
1
3
53.0 (d, JCP = 23 Hz, CH of C6H4C7H10), 126.7 (d, JCP = 11 Hz,
3
1
C6H4C7H10), 127.5 (d, JCP = 6 Hz, C6H4C7H10), 127.6 (d, JCP
=
=
37 Hz, ipso-C6H4C7H10), 128.6 (d, 3JCP = 10 Hz, Ph), 129.8 (d, 4JCP
2 Hz, C6H4C7H10), 130.4 (d, 4JCP = 2 Hz, Ph), 131.6 (d, 2JCP = 11 Hz,
2
1
Ph), 135.4 (d, JCP = 15 Hz, C6H4C7H10), 139.3 (d, JCP = 37 Hz,
ipso-Ph), 151.4 (d, JCP = 3 Hz, ipso-C6H4C7H10), 197.5 (d, JCP
7 Hz, JCW = 126 Hz, cis-CO), 198.9 (d, JCP = 21 Hz, trans-CO).
Anal. Calcd for C24H19O5PW: C, 47.87; H, 3.18. Found: C, 47.97; H,
3.20.
2
2
=
1
2
Compounds 17 (80 mg, 0.133 mmol) and dppe (63.5 mg, 0.159 mmol)
were dissolved in THF (3 mL) and irradiated with UV for 2.5 h,
resulting in a color change from colorless to yellow. The solvent was
removed under reduced pressure, and the residue was purified by flash
chromatography (alumina, 20/80 v/v diethyl ether/petroleum ether).
After purification, the free phosphine {PPh(C6H4C7H10)} (20) was
obtained as a yellow oil. Yield: 30 mg, 81%. 31P{1H} NMR (C6D6):
[W(CO)5{PPh2(C2Ph)}] (18).
1
δ − 29.9 (s). H NMR (C6D6): δ 0.97−1.28 (m, 5H, C6H4C7H10),
1.43−1.60 (m, 3H, C6H4C7H10), 2.01 (m, 1H, C6H4C7H10), 2.41−
2.47 (m, 1H, C6H4C7H10), 6.88−7.48 (m, 9H, 4H of C6H4C7H10 and
5H of Ph). 13C{1H} NMR (C6D6): δ 27.7 (d, JCP = 3 Hz, CH2 of
A solution of [W(CO)5{PPh2(OSO2CF3)}] (4) was prepared from
[W(CO)5{PPh2Cl}] (1; 100.0 mg, 0.184 mmol) and AgOSO2CF3
(56.7 mg, 0.221 mmol) in CH2Cl2 (5 mL) as described above.
Phenylacetylene (40.4 μL, 0.368 mmol) was added, and the mixture
was stirred for 10 min at room temperature, resulting in a color change
to brown. The solvent was removed in vacuo, and the residue was
purified by flash chromatography (silica gel, 5/95 v/v diethyl ether/
petroleum ether). Yellow crystals of [W(CO)5{PPh2(C2Ph)}] (18)
were obtained by cooling a saturated pentane solution to −20 °C.
Yield: 89 mg, 79%. IR (νCO, CH2Cl2, cm−1): 2074 (w), 1942 (vs).
C6H4C7H10), 30.6 (d, JCP = 13 Hz, CH2 of C6H4C7H10), 38.0 (d, JCP
=
3.9 Hz, CH of C6H4C7H10), 40.5 (d, JCP = 2 Hz, CH2 of C6H4C7H10),
41.6 (d, JCP = 24 Hz, CH of C6H4C7H10), 46.3 (s, CH of C6H4C7H10),
46.87 (d, JCP = 14 Hz, CH of C6H4C7H10), 126.3 (d, JCP = 7 Hz,
C6H4C7H10), 126.7 (s, C6H4C7H10), 127.2 (s, C6H4C7H10), 128.5
(s, Ph), 128.6 (s, C6H4C7H10), 128.8 (d, JCP = 1 Hz, Ph), 133.1 (d, JCP
=
14 Hz, Ph), 133.8 (d, JCP = 23 Hz, C6H4C7H10), 133.83 (s, Ph), 134.10
(s, C6H4C7H10). Note: Because compound 20 is an oil, complete
removal of trace solvent was not possible, and satifactory elemental
analysis could not be obtained. Spectra are provided in the Supporting
Information.
1
31P{1H} NMR (CDCl3): δ −7.0 (s, JPW = 244 Hz). 1H NMR
X-ray Crystallography. X-ray quality crystals of 17 were grown by
evaporation of the diethyl ether solution at room temperature. Crystals
of 19 were grown by slow diffusion of pentane into a saturated CH2Cl2
solution at −20 °C. Programs for diffractometer operation, data col-
lection, cell indexing, data reduction, and absorption correction were
those supplied by Bruker AXS Inc., Madison, WI. Diffraction mea-
surements were made on a PLATFORM diffractometer/SMART 1000
CCD using graphite-monochromated Mo Kα radiation at −80 °C.
Unit cells were determined from randomly selected reflections obtained
using the SMART CCD automatic search, center, index, and least-
squares routines. Integration was carried out using the program SAINT,
(CDCl3): δ 7.37−7.52 (m, 9H), 7.61−7.65 (m, 2H), 7.73−7.80
1
(m, 4H). 13C{1H} NMR (CDCl3): δ 83.2 (d, JCP = 84 Hz, CCPh),
110.5 (d, 2JCP = 14 Hz, CCPh), 121.2 (d, 3JCP = 2 Hz, ipso-Ph of alkyne
3
substituent), 128.9 (d, JCP = 14 Hz, Ph), 129.1 (s, alkyne-Ph), 130.5
(s, alkyne-Ph), 130.8 (d, 4JCP = 2 Hz, Ph), 131.5 (d, 2JCP = 14 Hz, Ph),
132.7 (s, alkyne-Ph), 135.2 (d, 1JCP = 49 Hz, ipso-Ph), 197.0 (d, 2JCP
=
1
2
7 Hz, JCW = 126 Hz, cis-CO), 199.7 (d, JCP = 22 Hz, trans-CO).
Compound 18 is a known compound, having been previously
prepared by an alternate route. These spectroscopic data match pre-
viously published data.23
I
DOI: 10.1021/acs.organomet.6b00348
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
and an absorption correction was performed using SADABS. Structure
solution was carried out using the SHELX29 suite of programs and the
WinGX graphical interface.30 Initial solutions were obtained by direct
methods and refined by successive least-squares cycles. All non-hydrogen
atoms were refined anisotropically.
Whittell, G. R.; Nagiah, S.; Ho, C.-L.; Wong, W.-Y.; Manners, I. Chem.
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Berlin/Heidelberg, 1988; Vol. 70, pp 27−102.
Computational Details. All calculations were performed with
the hybrid DFT functional B3LYP,31 as implemented in the Gaussian
09 (revision C.01 or D.01) software program.32 Basis sets used for
geometry optimizations and frequency calculations were LANL2DZ
for W and 6-31G(d,p) for other atoms (H, C, O, F, P, Al, Ga, and Cl).
The keywords used in the input files for optimization and frequency
calculations were # opt freq rb3lyp gen (pseudo = read was included
when a transition metal is present). Single-point energies were computed
at the B3LYP/LANL2TZ(F)/6-311g+(2d,p) level of theory with an
added polarizable continuum model (SCRF = IEFPCM) to account
for the dichloromethane solvent effect.33 The LANL2TZ(f)34 basis
set information was obtained from the EMSL basis set library.35
Phosphorus-31 NMR shielding constants, σ, were calculated on the
optimized structures using the gauge-independent atomic orbital
method (GIAO)36 with basis sets LANL2TZ(f) on W and 6-311g
+(2d,p) on other atoms. The keywords used in the input files for
NMR calculations were # NMR = giao rb3lyp gen (pseudo = read was
included when a transition metal is present). Phosphorus-31 chemical
shift values, δ, of the studied phosphorus compounds were obtained
by substituting the computed isotropic shielding constant values into
eq 1. Since calculating σ for aqueous H3PO4 is not practical, we used
one of our complexes (compound 1, δexptl 95.7 ppm) as a standard.
A similar approach has also been used previously to calculate δ on a
variety of organophosphorus compounds.37
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N. M.; Pavlovic, V. D.; Novakovic, I. T.; Matic, I. Z.;
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ASSOCIATED CONTENT
* Supporting Information
The Supporting Information is available free of charge on the ACS
Publications website at DOI: 10.1021/acs.organomet.6b00348.
■
S
NMR spectra for all new compounds and optimized
structures, numbers of imaginary frequencies, absolute
energies, 31P NMR shielding constants, NBO charges,
and Cartesian coordinates (PDF)
Crystallographic data for compounds 17 and 19 (CIF)
Coordinates of calculated structures (XYZ)
(11) Nakazawa, H.; Yamaguchi, Y.; Mizuta, T.; Ichimura, S.; Miyoshi,
K. Organometallics 1995, 14, 4635−4643.
(12) Jayaraman, A.; Sterenberg, B. T. Organometallics 2014, 33, 522−
530.
(13) Jayaraman, A.; Jacob, T. V.; Bisskey, J.; Sterenberg, B. T. Dalton
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AUTHOR INFORMATION
Corresponding Author
*E-mail for B.T.S.: brian.sterenberg@uregina.ca.
Notes
(15) Jayaraman, A.; Sterenberg, B. T. Organometallics 2013, 32, 745−
747.
■
(16) Kotz, J. C.; Nivert, C. L. J. Organomet. Chem. 1973, 52, 387−
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D. Can. J. Chem. 2002, 80, 1404−1409.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We thank Bob McDonald and Mike Ferguson (University of
Alberta) for X-ray data collection, Compute Canada (West-
Grid) for computing resources, and The National Science and
Engineering Research Council (grant number 2015-04634 to
B.T.S.), the University of Regina, and the Government of
Saskatchewan (2015 Saskatchewan Innovation and Opportu-
nity Scholarship to A.J.) for funding.
(18) Millot, N.; Santini; Catherine, C.; Fenet, B.; Basset; Jean, M.
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