C-H and C-C bond formation promoted by facile κ3/ κ2 interconversions in a hemilabile "click"-triazole scorpionate platinum system

Article abstract of DOI:10.1021/om2007997

A series of platinum complexes bearing 3-fold symmetrical "Click"-triazole-based scorpionate ligands (Tt^R) has been prepared. Metalation of these weakly donating ligands results in neutral Pt(II) complexes that display a κ² coordinat

Full text of DOI:10.1021/om2007997

Article
pubs.acs.org/Organometallics
C−H and C−C Bond Formation Promoted by Facile κ3/κ2
Interconversions in a Hemilabile “Click”-Triazole Scorpionate
Platinum System
Bryan E. Frauhiger, Peter S. White, and Joseph L. Templeton*
W. R. Kenan Laboratory, Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill,
North Carolina 27599-3290, United States
S
* Supporting Information
ABSTRACT: A series of platinum complexes bearing 3-fold
symmetrical “Click”-triazole-based scorpionate ligands (TtR)
has been prepared. Metalation of these weakly donating
ligands results in neutral Pt(II) complexes that display a κ2
coordination mode. Such complexes are susceptible to oxi-
dative addition using a variety of electrophilic alkyl and allyl
reagents to generate isolable cationic κ3 Pt(IV) complexes.
Protonation of the κ2 precursors results in Pt(IV) dimethyl
hydride cations. Thermolysis of the dimethyl hydride species
at 35 °C in the presence of a trapping π-acid ligand initiates
reductive elimination of methane and formation of a Pt(II)
species of the type [TtPhPtMe(L)][BF4] (L  CO, ethylene,
propylene, cis-2-butene, trans-2-butene, isobutylene) in good yield. Furthermore, the κ3 σ-allyl complexes [TtRPt(Ph)2-
(CH2CHCH2)][I] cleanly undergo Csp2−Csp2 reductive coupling to form biphenyl at ambient temperatures. The TtR ligand
serves as a homofunctional hemilabile ligand and exhibits a lower barrier κ3/κ2 interconversion to generate reactive unsaturated
five-coordinate complexes than the well-studied Tp′PtMe2H complex, which requires thermolysis at temperatures above 100 °C.
INTRODUCTION
■
Hemilabile ligands, in which a weakly donating group can
reversibly bind to a metal center, have risen in prominence in
metal−ligand system design due to the flexible coordination
mode geometry and the ease of formation of unsaturated
complexes, providing access to reactive intermediates.1,2 Such
systems stand in stark contrast to strongly donating ligand
scaffolds that result in stable, well-defined complexes that can
be reluctant reagents.3 Numerous multidentate ligand frame-
works have been reported that contain weakly coordinating and
readily tunable pendant functional groups that serve the role of
reversible donors.1,2,4−10
Our research program has focused on controlling intercon-
version between κ2 and κ3 coordination modes in the Tp′Pt
system (Tp′ = hydridotris(3,5-dimethylpyrazolyl)borate)
(Figure 1a)). It is well established that reductive elimination
from six-coordinate Pt(IV) often occurs from a five-coordinate
species through preliminary ligand dissociation.11−20 Although
Tp′ is a strong donor, we have found specific conditions
that allow us to control the reversible coordination of one
of the pyrazolyl rings, thus granting access to the coveted
five-coordinate intermediate. Thermolysis of Tp′PtMe2H above
100 °C or protonation at low temperature dechelates the
apical Tp′ arm, generating a reactive unsaturated species that
eliminates methane.21 An array of reactivity patterns stemming
from the resulting Tp′PtMe fragment has been documented
(Scheme 1).22−26 In the presence of cyclic alkanes, Tp′PtMe
Figure 1. Tp′ (a) and TtR (b) tridentate ligands.
activates C−H bonds and generates dehydrogenated products
after β-H elimination.22 Trapping Tp′PtMe with carbon mono-
xide results in formation of the Tp′PtMe(CO) complex, which
can undergo nucleophilic attack by hydroxide to generate CO2
and a platinum dihydride species. Elimination of dihydrogen
in a subsequent step represents a stoichiometric water gas
shift reaction.23 Furthermore, elimination of benzene from the
Received: August 25, 2011
Published: December 6, 2011
© 2011 American Chemical Society
225
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237

Organometallics
Article
Scheme 1. Generation of the Reactive Tp′PtR Fragment and Subsequent Reactivity
analogous Tp′PtPh2H and trapping with olefins lead to slow
phenyl migration and ortho C−H activation to form metalla-
cycles.24 The initiating mechanistic step for all of these transfor-
mations is dechelation of the apical Tp′ arm to generate a
RESULTS AND DISCUSSION
■
Synthesis and Metalation of TtR. Following Lammertsma’s
method, TtPh L1 was synthesized via the CuAAC reaction
between trisethynyl phosphine oxide and phenyl azide.40 In a
similar fashion, tris(1-cyclohexyl-1H-1,2,3-triazol-4-yl)-
phosphine oxide (TtCy) L2 was prepared using cyclohexyl
azide. The aromatic triazolyl proton of the rings in L1 and L2
reactive five-coordinate intermediate.
In hopes of facilitating conversion between κ3 and κ2
coordination modes for scorpionate ligands, the reactivity of
the neutral trispyrazolylmethane (Tpm) ligand in an analogous
Pt system was studied. To our surprise, [TpmPtMe2H]+ was
reluctant to eliminate methane even at 100 °C.27 It was clear
that the strongly donating pyrazolyl rings have a large influence
on κ3/κ2 interconversions. We, therefore, sought to probe
reactions utilizing both a weaker tridentate nitrogen donor
ligand and a more electrophilic backbone than C−H, which
should allow for coordination mode interconversion under
milder conditions.
1
resonates in the H NMR spectra at 8.8 and 8.2 ppm, respec-
tively, and serves as an excellent NMR symmetry handle.
The addition of TtPh or TtCy to a methylene chloride solution
of [Pt(CH3)2(SMe2)]2 results in displacement of the bridging
dimethyl sulfide ligands and formation of κ2 square-planar
complexes, κ2-TtPhPt(CH3)2 (1-L1) or κ2-TtCyPt(CH3)2 (1-L2)
(eq 1), in which two triazolyl rings bind through the N3
position. The crude mixtures were chromatographed to obtain
the κ2 products as air-stable light yellow solids in 61% and 68%
yield, respectively.
Hemilabile metal−ligand frameworks have promoted organo-
metallic reactions in platinum chemistry. Vedernikov and co-
workers have developed and employed the hemilabile di(2-
pyridyl)methane sulfonate (dpms) ligand to extensively study
metal−carbon functionalization using a Pt(II)/Pt(IV) system in
aqueous media.28−34 Similar to the monofunctional Tp′ ligand,
the proximal sulfonate group assists in stabilizing oxidized
Pt(IV) species enroute to functionalized products. Similarly,
both Vedernikov and Puddephatt have utilized a dipyridylke-
tone ligand that readily adds nucleophiles to create an anionic
ligand that can be either bidentate or tridentate.35,36
Recently, Lammertsma and co-workers employed copper
catalyzed azide−alkyne cycloaddition37−39 (CuAAC) in the
synthesis of tris(1-phenyl-1H-1,2,3-triazol-4-yl)phosphine oxide
(L1) (Figure 1b), a neutral, symmetrical 1,2,3-triazolyl-based
tridentate ligand, which we will abbreviate as TtPh.40 Despite
the wide versatility and efficiency of the CuAAC reaction,
utilization of 1,2,3-triazole-containing N-donor chelating
ligands in transition-metal complexes is rare.41−47 Anticipating
weak donation from the triazole ring compared with pyrazole
and increased electrophilicity of a PO backbone over B−H
and C−H, we were attracted to the potential of employing TtPh
to generate analogues of the Tp′PtR fragment under mild
conditions. Here, we report the synthesis of a series of TtRPt
complexes and their reactivity built upon κ3/κ2 coordination
mode flexibility, including C−X oxidative addition, C−H reduc-
tive elimination, and C−C reductive coupling, all accessible at
ambient temperatures.
In accord with weak donation anticipated for the triazolyl
ring, it should be noted that the TtR ligand readily cleaves the
bridges of the platinum dimer, but it does not readily dis-
place dimethyl sulfide present in the resulting monomer,
Pt(CH3)2(SMe2)2. Instead, when more than 1 equiv of TtR is
added to [Pt(CH3)2(SMe2)2]2, the first equivalent rapidly
coordinates to one-half of the platinum in the dimer, while an
equilibrium is established for the remaining platinum that
reflects competition between TtR and dimethyl sulfide to bind
to Pt(II). Indeed, addition of dimethyl sulfide to clean 1 results
in a mixture of bound and free TtR (eq 2). Attempts at heat-
ing the mixture to drive off the free dimethyl sulfide were
unsuccessful and led to decomposition and undesired side
reactions.
226
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237

Organometallics
Article
The 1H NMR spectrum of κ2-TtPhPt(CH3)2 (1-L1) reveals a
2:1 ratio for the triazolyl proton resonances, and a single signal
for the two Pt−Me groups, indicating a Cs symmetric complex.
The rather large chemical shift difference of 1 ppm between the
two triazolyl proton resonances demonstrates that the apical
arm is in a significantly different chemical environment, con-
sistent with a κ2 coordination mode. The Pt−Me resonance
Table 1. Selected Bond Lengths (Å) and Angles (°) for
Complex 3a-L1
Bond Lengths
Pt(1)−C(1)
Pt(1)−C(2)
Pt(1)−C(3)
P(1)−O(1)
2.039(3)
Pt(1)−N(1)
Pt(1)−N(2)
Pt(1)−N(3)
2.189(2)
2.168(2)
2.175(2)
2.043(3)
2.045(3)
1.468(2)
2
at 0.9 ppm with JPt−H = 88 Hz is compatible with data for
Bond Angles
other Pt(II)−Me resonances.25,48,49 The phosphine oxide
resonance in the 31P NMR spectrum moves slightly upfield
from −5.7 ppm for free TtPh to −8.4 ppm when two scorpio-
C(1)−Pt(1)−C(2)
C(2)−Pt(1)−C(3)
C(3)−Pt(1)−C(1)
C(1)−Pt(1)−N(3)
C(2)−Pt(1)−N(1)
C(3)−Pt(1)−N(2)
87.32(12)
87.59(13)
88.81(12)
92.18(10)
93.97(11)
93.36(11)
N(1)−Pt(1)−N(2)
N(2)−Pt(1)−N(3)
N(3)−Pt(1)−N(1)
85.30(9)
86.08(9)
85.92(9)
1
nate arms bind to the metal. It is noteworthy that the JP−C
value at the dome of the scorpionate umbrella is dependent
upon the binding of the triazolyl ring, so this coupling constant
serves as a convenient spectroscopic probe of the coordination
mode. In 1-L1, 1JP−C is 167 Hz for the lone unbound arm while
1JP−C decreases to 151 Hz for the two coordinated rings. Similar
NMR characteristics were observed for the corresponding 1-L2
dimethyl complex. Analogous diphenyl complexes κ2-TtPhPt-
(Ph)2 (2-L2) and κ2-TtCyPt(Ph)2 (2-L2) were prepared in the
same manner using [Pt(Ph)2(SEt2)2]2 as a platinum source,
resulting in 56% and 74% yields by the TtR ligand (R = Ph and
Cy), respectively.
1
(X = OTf or I). The H NMR spectrum of [(κ3-TtPh)Pt-
(CH3)3][OTf] (3a-L1) shows a single resonance at 9.4 ppm
for the three triazolyl ring protons, indicating an ascent in
symmetry to the C3v point group. The Pt−Me resonance moves
downfield to 1.5 ppm and is consistent with other reported
systems involving Pt(II)/Pt(IV) oxidations.26,50−52
Slow diffusion of hexanes into a methylene chloride solution
of 3a-L1 (after counterion exchange with [Na][B(3,5-(CF3)2-
C6H3)4] (NaBAr′4)) produced clear, colorless hexagonal
crystals that were suitable for X-ray crystallography. Figure 2
shows the X-ray structure of 3a-L1, which adopts an octahedral
geometry with a κ3 coordination mode of the TtPh ligand. The
Pt−C bond lengths (2.039−2.045 Å) are consistent with other
LPtMe3 (L = tridentate donor) complexes.53,54 This distance, in
conjunction with the 2JPt,H value of 74 Hz, is in good agreement
with the well-defined trend highlighted by Goldberg et al. that
correlates shorter Pt−C distances (≤2.05 Å) due to weakly
donating trans ligands with larger two-bond couplings
(>70 Hz) in Pt(IV)-Me compounds.53 Comparison of the
Pt−N distance in [TtPhPtMe3][BAr′4] to both Tp′PtMe3 and
[TpmPtMe3][I] reveals a consistent pattern of slight length-
ening, roughly 0.02 Å, that is also compatible with less donation
from the 1,2,3-triazole.53,54 The angles around the platinum center
are slightly distorted from ideal; both the N−Pt−N angles
(85−86°) and the C−Pt−C (87−89°) angles are slightly pinched,
resulting in larger C−Pt−N angles (92−94°). All three phenyl
groups of the TtPh ligand are twisted from their respective triazolyl
ring plane, with two rotated 28° and 29° in the same direction,
while the other is tilted 36° in the opposite direction.
Cationic Pt(IV) Alkyl and Allyl Complexes. Treatment
of the dimethyl κ2 complex 1 with electrophilic alkyl and allyl
reagents resulted in oxidation of the metal center to form
isolable octahedral platinum(IV) cations 3a−3e (eq 3, Table 1)
In a similar manner to 3a, [TtRPtMe2Et][X] (3b) was pre-
pared by addition of ethyl triflate or ethyl iodide to 1. The ethyl
complexes maintain the mirror plane present in their κ2
precursors and exhibit a 2:1 ratio for the triazolyl proton
resonances in the 1H NMR, but the two signals are much closer
in chemical shift (ca. 0.1 ppm difference), no doubt reflecting
κ3 coordination with an alkyl ligand trans to each nitrogen
donor. In 3b-L1, the methylene protons of the ethyl group
appear as a quartet at 2.4 ppm with Pt satellites (2JPt−H = 75 Hz),
whereas the beta protons resonate as a triplet at 0.9 ppm (3JPt−H
=
56 Hz). The ability to use primary halides for alkylation of
Pt(II) was further demonstrated with 1-iodopropane. Treat-
Figure 2. X-ray structure of [TtPhPtMe3][BAr′4] 3a-L1. Ellipsoids are
drawn at the 50% probability level. Hydrogen atoms, the BAr′4
counterion, and cocrystallized CH2Cl2 are omitted for clarity.
ment of 1 with 1-iodopropane resulted in [TtRPtMe2 Pr][I]
n
(3c). However, the reaction was significantly slower than the
methyl and ethyl analogues and required stirring overnight at
room temperature for completion.
in quantitative yield by 1H NMR. All compounds were
1
characterized by H, 13C, and 31P NMR spectroscopies.
Addition of either methyl triflate or methyl iodide to 1-L1
1 was treated with allyl iodide, 3-bromo-2-methylpropene, or
benzyl iodide to form the corresponding Pt(IV) σ-allyl or
resulted in a trimethyl species of the type [(κ3-TtPh)PtMe3][X]
227
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237

Organometallics
Article
1
Figure 3. Allyl region of 3d-L1 in the H NMR spectrum.
σ-benzyl complexes 3d−3f. The synthesis of 3e and 3f was
performed in the presence of 1.3 equiv of AgBF4 to form the
tetrafluoroborate salt. [TtPhPtMe2(CH2CHCH2)][I] (3d-
L1) exhibits the characteristic 2:1 ratio and close chemical shift
values of the triazolyl protons, and a downfield Pt−Me
chemical shift is observed at 1.6 ppm consistent with a Pt(IV)
complex with a κ3 TtPh coordination mode. The allyl region of
5-L1 exhibits a hydride signal at −19.9 ppm with a large Pt
coupling, 1JPt−H = 1541 Hz. The one-bond Pt−H coupling is an
indirect probe of the strength of the trans ligand bond to
platinum. In Tp′PtMe2H, the coupling is 1360 Hz, so the
triazole in TtPh is indeed a weaker donor than the pyrazole in
Tp′.55 In the TtCy analogue [TtCyPtMe2H][BF4] (5-L2), JPt−H
1
is 1519 Hz, indicating that the TtCy ligand is a slightly stronger
donor than TtPh.
1
the H NMR (Figure 3) displays a typical α-olefin pattern of
η1-allyl ligands, including a doublet for the equivalent
methylene protons and a large two-bond coupling to platinum,
2JPt−H = 96 Hz. Platinum coupling (ca. 20 Hz) is also observed
through the allyl fragment to the terminal protons which are
four bonds removed from the metal center. NMR spectra of
both the methyl-substituted allyl (3e) and benzyl (3f)
complexes are consistent with data obtained for 3d.
In the EXSY NMR spectrum (Figure 4) of 5-L1, an off-
diagonal crosspeak with platinum satellites is present that
correlates the Pt−H and the Pt−CH3 signals. This peak is in-
phase with the diagonal signals, indicating slow exchange on the
NMR time scale rather than distance-dependent nuclear
Overhauser effects.56 Exchange between the hydride and methyl
protons indicates a dynamic metal−ligand system at room tem-
perature, and we postulate that this exchange proceeds through a
low-barrier dechelation of the apical TtR ligand arm to generate a
five-coordinate complex that can reductively couple H and CH3
to form an agostic methane adduct. Such species are often
proposed intermediates in metal-mediated processes involv-
ing C−H addition or elimination.57,58 Rotation of the bound
methane and oxidative addition of a different C−H bond,
followed by κ2/κ3 conversion, completes the exchange of the
methyl and hydride positions. Methane loss can occur directly
from the putative η2-CH4 adduct, as verified by the presence of
Analogous diphenyl alkyl complexes were prepared using
2-L1 and 2-L2 as starting materials. Methylation of the κ2 com-
plexes using methyl triflate or methyl iodide resulted in complexes
of the type [TtRPtPh2Me][X] (X = OTf or I) (4a). The Pt−Me
resonance moves significantly downfield to 2.3 ppm (2JPt−H
=
74 Hz) as a result of deshielding by the two adjacent aromatic
rings. Reaction of 2 with ethyl triflate or ethyl iodide produced the
expected diphenyl ethyl complexes, [TtRPtPh2Et][X] (X = OTf
or I) (4b). However, addition of 1-iodopropane did not result in
oxidative addition even at longer reaction times. The presence of
metal bound aromatic rings clearly reduced the nucleophilicity of
the metal center relative to the Pt(II) dimethyl case.
1
small amounts of methane at ca. 0.2 ppm in the H NMR
spectrum.59
This interconversion process was confirmed by the addition
1
Synthesis of [TtRPtMe2H]+. The addition of alkyl or allyl
electrophiles to the κ2-TtR complexes demonstrated that the
metal center is susceptible to oxidation to form stable Pt(IV)
products. With this reactivity in mind, we sought to form an
analogous dimethyl hydride complex for comparison with
Tp′PtMe2H. Reaction of 1-L1 with mild H+ sources, such as
NH4Cl or AcOH, did not produce the desired [TtPhPtMe2H]+.
Protonation using a strong acid, HBF4·Et2O, was required to
generate [TtPhPtMe2H][BF4] (5-L1) (eq 4).
of D2O and monitoring the H NMR spectrum. Initial spectra
indicate that deuterium is incorporated into the acidic hydride
position. After 5 min, a new methyl signal begins to appear due
to the formation of Pt−CDH2. As deuterium incorporation
proceeds, the Pt−CH3 signal continues to decrease in intensity
while the Pt−CDH2 and, later, Pt−CD2H signals appear and
1
grow (Figure 5). After 30 min, the upfield region of the H
NMR displays various CHnD4−n (n = 4, 3, or 2) methane
isotopologues (Figure 6) due to methane loss from the
deuterated dimethyl hydride cation. The proposed mechanism
for deuterium incorporation (Scheme 2) proceeds as described
above, which is analogous to deuterium incorporation in the
related Tp′Pt(CH3)2D.21
Reductive Elimination from [TtRPtMe2H]+. Given the
dynamic nature of the [TtRPtMe2H]+ reagents, we wanted to
drive the interconversion to the κ2 form and favor methane loss
from the unsaturated five-coordinate intermediate under mild
228
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237

Organometallics
Article
Figure 4. EXSY NMR spectrum of 5-L1.
1
Figure 5. Methyl and hydride regions of the H NMR spectrum in 5-L1 after addition of excess D2O.
conditions. Indeed, heating 5 at 35 °C under a CO atmosphere
for 2 h resulted in conversion to the cationic carbon monoxide
complexes, [TtRPtMe(CO)][BF4] (6) (eq 5) in good yield
donor. In Tp′PtMe(CO), two distinct CO stretches (2065 and
2081 cm−1) were observed that reflect the presence of both
four-coordinate κ2 and five-coordinate κ3 isomers.60 The
existence of only one CO stretch in 6 along with the high
electrophilicity at platinum is compatible with the observation
of solely the κ3 form.
1
(86%) by H NMR. The solution IR spectra of 6-L1 and
6-L2 reveal a strong CO band at 2124 and 2117 cm−1, respec-
tively. These high CO stretches (approaching that of free CO
at 2139 cm−1) indicate an exceptionally electron-deficient
metal center, reiterating that the triazolyl ligand is a weak
1
The H NMR spectrum of 6-L1 displays a 2:1 ratio for the
triazolyl resonances and a Pt−Me signal at 1.4 ppm (2JPt−H = 74 Hz)
229
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237

Organometallics
Article
with a trigonal bipyramidal geometry about the platinum
center, similar to that of 6. The four olefinic protons in both of
these complexes appear as a singlet (2JPt−H = 79 and 81 Hz,
respectively), reflecting rapid rotation about the metal−ligand
bond that averages the up and down (relative to the axial
nitrogen) olefin signals. Variable-temperature NMR studies
reveal that the olefin is static at 220 K in 7a-L1, with two
separate resonances as a result of inequivalent sites for the
up and down protons of the bound alkene (Figure 7).
1
Figure 6. Methane region of the H NMR spectrum in 5-L1 30 min
after the addition of excess D2O.
Figure 7. Variable-temperature NMR study of ethylene rotation in 7a-
L1 (a) and 7a-L2 (b).
and suggests a Cs symmetric bipyramidal geometry. The 13C
NMR spectrum contains the characteristic downfield metal
carbonyl resonance at 161.3 ppm.
The coalescence temperature for this process was found to be
239 K for 7a-L1, which translates to a rotation barrier of 11.1
( 0.2) kcal/mol. The TtCy analogue, 7a-L2, had a coalescence
temperature of 248 K and a rotation barrier of 11.5 ( 0.2)
kcal/mol. Presumably, the TtCy ligand is slightly more electron-
rich and enhances backbonding to the olefin in the ground-state
geometry.
Applying the same reaction conditions, but using ethylene in
place of carbon monoxide as the trapping gas, generated η2-
ethylene complexes, [TtRPtMe(η2-C2H4)][BF4] (7a) (eq 5).
1
The 13C NMR spectra of 7a-L1 reveal JP−C values of 153 and
150 Hz for the apical and equatorial nitrogen donors,
respectively, indicating that all three triazolyl arms are bound
The scope of the methane elimination/trapping sequence
was expanded using the TtPh ligand and a series of substituted
Scheme 2. Proposed Mechanism for Deuterium Incorporation into the Methyl Position
230
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237

Organometallics
Article
olefins. Heating 5-L1 at 35 °C for 4 h under an atmosphere of
propylene, cis-2-butene, trans-2-butene, or isobutylene pro-
duced the corresponding η2 olefin complexes 7b−7e in
We believe that the mechanism for biphenyl elimination
from 4c involves a sequence that is some combination of ligand
dechelation, iodide addition, and η1-to-η3 allyl rearrangement.
Combinations of these simple steps lead to six different
pathways (Scheme 3). In all cases, the initiating step is a low-
1
74−78% yield by H NMR. [TtPhPtMe(η2-propylene)][BF4]
(7b) displays three unique resonances in a 1:1:1 ratio for the
triazolyl protons, reflecting the descent to C1 symmetry. In both
the cis-2-butene and the trans-2-butene complexes 7c-L1 and
7d-L1, the olefinic region of the 1H NMR spectra displays two
broad resonances at 298 K and indicates that room temperature
is slightly below the coalescence temperature for rotation.
However, in the isobutylene adduct 7e-L1, both olefinic
protons as well as both methyl groups appear as sharp singlets,
revealing rapid rotation at room temperature.
Scheme 3. Possible Mechanistic Pathways for the
Elimination of Biphenyl from 4c
Biphenyl Formation via C−C Reductive Coupling. Addition
of allyl iodide or benzyl bromide to the diphenyl precursor 2
resulted in the expected product, [TtRPtPh2R][I] (R = allyl 4c,
benzyl 4d), and these Pt(IV) complexes are analogous to their
dimethyl counterparts. However, whereas 3d and 3f are
unreactive, complexes 4c and 4d undergo reductive C−C
coupling to cleanly produce biphenyl, and this reaction is
accompanied by release of TtR. The rate of reaction was found
to be heavily influenced by the identity of the triazolyl ligand;
elimination from the TtPh allyl complex 4c-L1 was complete
within 15 min at room temperature, whereas the TtCy complex
4c-L2 proceeds slowly overnight. Counterion exchange using
AgBF4 shuts down the biphenyl production and results in an
isolated, stable complex (eq 6).
Kinetic studies on the conversion of [4c-L2][I], which is
formed rapidly in situ upon addition of allyl iodide to 2, to
1
biphenyl and free TtCy ligand were performed with H NMR
spectroscopy by monitoring the appearance of biphenyl. The
kinetics of this reaction were studied over a temperature range
from 290 to 320 K; the reaction displayed second-order
kinetics. The rate at 300 K was found to be 1.29 ( 0.03) ×
barrier κ3-to-κ2 conversion to generate an unsaturated five-
coordinate intermediate. The κ2 complex can be trapped by
either a σ- to π-allyl wrap to produce intermediate I-1 or by
coordination of the iodide counterion to form I-2. Both I-1 and
I-2 could undergo a reversible κ2-to-κ1 conversion to lose the
second arm of the TtR ligand and again be trapped by either
iodide (Path A) or the allyl (Path C), respectively. Loss of the
third TtR arm produces an unsaturated intermediate from
which biphenyl elimination can occur along with generation of
the iodide-bridged π-allyl dimer I-7. Alternatively, biphenyl
elimination could occur after the κ2/κ1 conversion from I-1
(Path B) or I-2 (Path D) and the resulting three-coordinate
Pt(II) fragment could be trapped with iodide or allyl,
respectively, to also yield I-7. The formation of a π-allyl
dimer is supported by the appearance of a doublet at 1.5 ppm
with Pt satellites (2JPt,H = 65 Hz) and a broad signal at 3.7 ppm
while monitoring the reaction using 4c-L1 as the starting
10−4 M−1 s−1, giving rise to a ΔG‡
value of 22.9 ( 0.2)
300 K
kcal/mol. An Eyring plot (Figure 8) was constructed using rate
constants from this temperature range; ΔH‡ and ΔS‡ are 19.1
( 1) kcal/mol and −12.6 ( 4) eu, respectively.
1
material. The two signals correlate to each other in the H,1H-
COSY NMR spectrum. However, the dimer begins to
decompose to Pt0 shortly after formation.
The remaining two pathways stem from Csp2−Csp2
elimination directly from the initial five-coordinate intermediate
Figure 8. Eyring plot of biphenyl formation from 4c-L2.
231
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237

Organometallics
Article
spectrometer. Mass spectral data are reported for the most abundant
platinum isotope. Tris(1-phenyl-1H-1,2,3-triazol-4-yl)phosphine oxide
(TtPh)40 (L1), [Pt(CH3)2(SMe2)2]2,63 [Pt(C6H5)2(SEt2)2]2,64 [Na]-
[B(3,5-(CF3)2C6H3)4] (NaBAr′4),65 [H(OEt2)2][B(3,5-
(CF3)2C6H3)4] (HBAr′4),65 benzyl iodide,66 and tris(ethynyl)-
phosphine oxide40 were synthesized using published procedures.
Synthesis of TtCy. Cyclohexyl Azide. A modified version of
Sharpless’s procedure was performed.67 Sodium azide (1.3 g, 20 mmol)
and potassium iodide (0.034 g, 0.2 mmol) were added to a 7 mL DMF
solution of cyclohexyl bromide (1.4 mL, 11.6 mmol). The reaction
mixture was refluxed overnight at 90 °C. Water (20 mL) was added
to the crude mixture, and the product was extracted with diethyl ether
(40 mL). The organic layer was washed with H2O (8 × 20 mL). The
ether solution was dried over MgSO4 and the solvent was evaporated to
produce cyclohexyl azide (1.00 g, 8.0 mmol) as a yellow oil in 69%
yield.
to generate a three-coordinate fragment, which, again, can be
trapped by either the iodide counterion (Path E) to form I-4 or
conversion from a σ- to π-allyl wrap (Path F) to form I-5. A
second iteration of κ2/κ1 TtR conversions and trapping yields
the Pt dimer I-7.
It should be noted that the diphenyl methyl complex 4a does
not result in C−C bond formation, which, along with the
inertness of the 4c BF4 counterion complex, indicates that the
iodide counterion and the allyl are both critical components to
biphenyl production. Assuming that the C−C coupling is not a
reversible mechanistic step, this would rule out Paths B and
D−F. We believe that the second-order kinetics indicate that
the bimolecular reaction of the complex cation with the iodide
counterion occurs on the way to the transition state. Thus, the
components present in the rate-determining step cannot be
used to rule out either Path A or Path C. However, the former
may be more appealing due to the proximity of an internal allyl
trap in competition with a bimolecular trapping with iodide.
The negative entropy of activation value suggests that the
trapping by iodide precedes the rate-determining step. If the
Csp2−Csp2 reductive elimination step occurs after the rate-
determining step, as seems likely, the associated enthalpy of
activation must be less than the value of 19.1 kcal/mol
measured for the enthalpy of activation for the overall reaction.
Previously, 17.7 kcal/mol was reported for the enthalpy of
activation for elimination from a Pt(II) metal center to give
biaryl and Pt(0) products.61
Tris(1-cyclohexyl-1H-1,2,3-triazol-4-yl)phosphine Oxide (TtCy)
(L2). A modified version of Lammertsma’s synthesis of TtPh was
performed.2 Sodium ascorbate (0.80 mL of a 1 M aqueous solution,
0.8 mmol) and CuSO4 (0.35 mL of a 2 M aqueous solution, 0.7 mmol)
were added to a suspension of tris(ethynyl)phosphine oxide (0.530 g,
4.4 mmol) and cyclohexyl azide (1.7 g, 13.6 mmol) in 8 mL of a 1:1
mixture of H2O and tBuOH. The reaction was allowed to stir
overnight at room temperature. The cloudy, peach-colored crude reac-
tion mixture was extracted with CH2Cl2 and dried over MgSO4. The
mixture was then passed through a Celite plug, the solvent was
evaporated, and the resulting oil was triturated with pentane to
produce TtCy (2.1 g, 4.2 mmol) as a white powder in 93% yield.
For simplity in presenting NMR data, the carbon atoms of the
cyclohexyl group are designated by the labeling scheme in Figure 9.
CONCLUSION
■
A series of platinum complexes bearing tridentate facially
coordinating “Click”-triazole scorpionate ligands (TtR) has
been synthesized. These hemilabile ligands allow for a
significantly lower barrier for κ3/κ2 interconversions compared
with the strongly donating pyrazolyl-based Tp′. The addition of
R+ or H+ reagents to the κ2-coordinated precursors TtRPtR2
results in an oxidized metal center to which the once-free apical
triazolyl arm can rapidly and reversibly bind. Mild heating of
the cationic TtR dimethyl hydride complexes at 35 °C suffices
for conversion to an unsaturated five-coordinate species from
which C−H reductive elimination and methane loss occurs. In
the TtR diphenyl σ-allyl reagents, the weakly donating TtR
ligand works in cooperation with the allyl fragment to produce
Csp2−Csp2 coupled products. This work demonstrates the
hemilability of the 1,2,3-triazole functionality and highlights
their potential use in symmetrical or hybrid multidentate
ligand−metal system design.
Figure 9. Carbon labels in the cyclohexyl group of the TtCy ligand.
1H NMR (CD2Cl2, 300 K, δ): 8.24 (s, 3H, TtCyCH), 4.50 (m, 3H,
CA-H), 2.23−1.33 (m, 30H, cyclohexyl). 31P{1H} NMR (CD2Cl2,
291 K, δ): −6.6 (s, 1P, TtCyPO). 13C{1H} NMR (CD2Cl2, 300 K,
δ): 140.8 (d, 3C, OPC, 1JP−C = 157 Hz), 129.1 (d, 3C, OPCCH,
2JP−C = 29 Hz), 61.0 (s, 3C, CA), 33.9 (s, 6C, CB) 25.5 (s, 6C, CC),
25.4 (s, 3C, CD). Anal. Calcd for C24H36N9OP: C, 57.93; H, 7.29; N,
25.33. Found: C, 58.00; H, 7.21; N, 25.16.
Synthesis of κ2-TtRPt(R′)2 Complexes. (κ2-TtPh)Pt(CH3)2
(1-L1). [Pt(CH3)2(SMe2)2]2 (0.040 g, 0.070 mmol) and TtPh
(0.033 g, 0.070 mmol) were placed in a Schlenk flask under nitrogen.
CH2Cl2 (10 mL) was added through the septum, and the reaction
mixture was stirred for 30 min at room temperature. After removal of
the solvent, the resulting oil was chromatographed on silica gel. The
column was first flushed with ethyl acetate, and this was followed by
methanol. The methanol eluant was collected, and the solvent was
evaporated to produce (κ2-TtPh)Pt(CH3)2 (0.020 g, 0.030 mmol) as a
pale yellow solid in 61% yield (by TtPh ligand). 1H NMR (CD2Cl2, 288
K, δ): 9.91 (s, 1H, TtPhCH), 8.82 (s, 2H, TtPhCH), 7.80−7.58
EXPERIMENTAL SECTION
■
Materials and Methods. All reactions were performed under an
atmosphere of dry nitrogen using standard Schlenk and drybox
techniques. Nitrogen was purified by passage through columns of
BASF R3-11 catalyst and 4 Å molecule sieves. Methylene chloride,
hexanes, and pentane were purified under an argon atmosphere and
passed through a column packed with activated alumina.62 All other
chemicals were used as received without further purification. Silica
column chromatography was conducted with 230−400 mesh silica gel,
and alumina column chromatography was conducted with 80−200
mesh alumina.
2
(m, 15H, TtPhC6H5), 0.91 (s, 6H, JPt−H = 88 Hz, Pt-CH3). 31P{1H}
3
NMR (CD2Cl2, 293 K, δ): −8.4 (s, 1P, TtPhPO, JPt−P = 26 Hz).
13C{1H} NMR (CD2Cl2, 293 K, δ): 139.1 (d, 1C, OPC, 1JP−C = 167
Hz), 138.2 (d, 2C, OPC, 1JP−C = 151 Hz), 136.2, 136.1 (s, 1C, 2C,
ipso-Ph), 130.2, 130.0 (s, 4C, 2C, o-Ph), 129.5 (s, 3C, p-Ph), 129.5
1H, 31P, and 13C NMR spectra were recorded on Bruker DRX400,
AVANCE400, or AMX300 spectrometers. H NMR and 13C NMR
1
2
chemical shifts were referenced to residual H and 13C signals of the
1
(d, 2C, OPCCH, JP−C = 25 Hz), 121.0, 120.7 (s, 4C, 2C, m-Ph),
1
−19.4 (s, 2C, Pt-CH3, JPt−C = 839 Hz). Anal. Calcd for
deuterated solvents. Elemental analyses were performed by Robertson
Microlit Laboratories of Madison, New Jersey. High-resolution mass
spectra were recorded on a Bruker BioTOF II ESI-TOF mass
C26H29N9OPPt: C, 44.26; H, 3.57; N, 17.87. Found: C, 44.41; H,
3.43; N, 17.60.
232
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237

Organometallics
Article
(κ2-TtCy)Pt(CH3)2 (1-L2). [Pt(CH3)2(SMe2)2]2 (0.040 g, 0.070 mmol)
and TtCy (0.035 g, 0.070 mmol) were placed in a Schlenk flask under
nitrogen. CH2Cl2 (10 mL) was added through the septum, and the
reaction mixture was stirred for 30 min at room temperature. After
removal of the solvent, the resulting oil was purified by flash
chromatography on alumina. The column was first flushed with ethyl
acetate, and this was followed by methanol. The methanol eluant was
collected, and the solvent was evaporated to produce (κ2-TtCy)Pt-
(CH3)2 (0.034 g, 0.048 mmol) as a white solid in 68% yield (by TtCy
ligand). 1H NMR (CD2Cl2, 290 K, δ): 9.26, 8.29 (s, 1H, 2H, TtCyCH),
4.49 (m, 3H, CA-H), 2.20−1.27 (m, 30H, cyclohexyl), 0.69 (s, 6H,
2JPt−H = 88 Hz, Pt-CH3). 31P{1H} NMR (CD2Cl2, 291 K, δ): −6.5 (s,
1P, TtCyPO). 13C{1H} NMR (CD2Cl2, 293 K, δ): 138.4 (d, 1C,
General Method B. To a 50 mL Schlenk flask, κ2-TtRPt(R′)2
(0.030 mmol) and AgBF4 (0.10 mmol) were placed under nitrogen.
CH2Cl2 (10 mL) was added through the septum, and the solution was
treated with 1.3 equiv (0.045 mmol) of the appropriate electrophilic
reagent at room temperature. After 20 min, the cloudy solution was
cannula filtered five times. The solvent was evaporated and the
resulting oil was triturated with pentane to afford the trialkyl platinum
1
product as a light yellow powder in quantitative yield by H NMR.
[(κ3-TtPh)PtMe3][X] (3a-L1). The procedure in general method A
was followed using methyl iodide or methyl triflate as the electrophile.
1
NMR data for the OTf counterion complex are reported. H NMR
(CD2Cl2, 300 K, δ): 9.14 (s, 3H, TtPhCH), 7.85−7.60 (m, 15H,
2
TtPhC6H5), 1.52 (s, 9H, JPt−H = 74 Hz, Pt-CH3). 31P NMR (CD2Cl2,
1
1
300 K, δ): −9.9 (s, 1P, TtPhPO). 13C{1H} NMR (CD2Cl2, 300 K,
OPC, JP−C = 167 Hz), 137.5 (d, 2C, OPC, JP−C = 151 Hz),
2
1
130.5 (d, 2C, OPCCH, JP−C = 32 Hz), 129.1 (d, 1C, OPCCH,
δ): 136.2 (d, 3C, OPC, JP−C = 150 Hz), 135.6 (s, 3C, ipso-Ph),
2JP−C = 29 Hz), 62.3, 60.7 (s, 2C, 1C, CA), 33.8−33.3 (s, 1:1:1, 6C,
(CB), 25.4−25.1 (s, 1:1:1 and 2:1, 9C, (CC and CD), −20.1 (s, 2C, Pt-
2
131.8 (s, 3C, p-Ph), 130.8 (d, 3C, OPCCH, JP−C = 24 Hz), 130.3
1
(s, 6C, o-Ph), 121.7 (s, 6C, m-Ph), −6.2 (s, 3C, Pt-CH3, JPt−C
=
1
692 Hz). Anal. Calcd for C28H27F3N9O4PPtS: C, 38.71; H, 3.13; N,
14.51. Found: C, 38.68; H, 3.02; N, 14.23.
CH3, JPt−C = 839 Hz).
(κ2-TtPh)Pt(Ph)2 (2-L1). [Pt(Ph)2(SEt2)2]2 (0.061 g, 0.070 mmol)
and TtPh (0.033 g, 0.070 mmol) were placed in a Schlenk flask under
nitrogen. CH2Cl2 (10 mL) was added through the septum, and the
reaction mixture was stirred for 30 min at room temperature. After
evaporation of the solvent, the resulting oil was purified by flash
chromatography on alumina. The column was flushed with ethyl
acetate and then by methanol. The methanol eluant was collected, and
the solvent was removed by rotary evaporation to produce (κ2-
TtPh)Pt(Ph)2 (0.033 g, 0.039 mmol) as a white solid in 56% yield. 1H
NMR (CD2Cl2, 300 K, δ): 9.27, 8.87 (s, 1H, 2H, TtPhCH), 7.80−7.51
[(κ3-TtPh)PtMe3][BAr′4] ([3a-L1][BAr′4]). In a 50 mL Schlenk flask,
3a-L1 (0.020 g, 0.027 mmol) and NaBAr′4 (0.057 g, 0.080 mmol)
were placed under nitrogen. CH2Cl2 (6 mL) was added through the
septum, and the solution was allowed to stir for 1 h. The solution was
cannula filtered three times and then concentrated to ca. 1 mL. Slow
diffusion of hexanes into the CH2Cl2 solution produced clear,
hexagonal crystals suitable for X-ray diffraction.
[(κ3-TtCy)PtMe3][X] (3a-L2). The procedure in general method A
was followed using methyl iodide or methyl triflate as the electrophile.
3
(m, 15H, TtPhC6H5), 7.07 (d, 4H, JPt−H = 52 Hz, Pt-Ar Ho),
1
NMR data for the OTf counterion complex are reported. H NMR
6.70−6.77 (m, 6H, Pt-Ar Hm and Hp). 31P{1H} NMR (CD2Cl2, 294 K,
(CD2Cl2, 300 K, δ): 8.68 (s, 3H, TtCyCH), 4.65 (m, 3H, CA-H),
2.22−1.30 (m, 30H, cyclohexyl), 1.32 (s, 9H, 2JPt−H = 73 Hz, Pt-CH3).
31P NMR (CD2Cl2, 300 K, δ): −7.5 (s, 1P, TtCyPO). 13C{1H} NMR
(CD2Cl2, 300 K, δ): 135.6 (d, 3C, OPC, 1JP−C = 150 Hz), 130.1 (d,
δ): −8.7 (s, 1P, TtPhPO). 13C{1H} NMR (CD2Cl2, 293 K, δ): 141.0
1
(s, 2C, Pt-Ar ipso-Ph), 140.5 (d, 1C, OPC, JP−C = 170 Hz), 139.0
1
(d, 2C, OPC, JP−C = 149 Hz), 138.8 (s, 4C, Pt-Ar m-Ph), 136.5,
136.2 (s, 1C, 2C, TtPh ipso-Ph), 130.9 (s, 2C, TtPh p-Ph), 130.6 (s, 4C,
2
3C, OPCCH, JP−C = 24 Hz), 63.4 (s, 3C, CA), 33.5 (s, 6C, CB),
1
TtPh o-Ph), 130.5 (d, 1C, JP−C = 33 Hz, OPC), 130.3 (s, 2C, TtPh
1
25.3 (s, 6C, CC), 25.1 (s, 3C, CD), −6.7 (s, 3C, Pt-CH3, JPt−C
=
2
o-Ph), 130.1 (s, 1C, TtPh p-Ph), 130.1 (d, 2C, JP−C = 25 Hz, OP
692 Hz). Anal. Calcd for C28H45F3N9O4PPtS: C, 37.92; H, 5.11; N,
14.21. Found: C, 37.65; H, 4.94; N, 13.98.
CCH), 126.3 (s, 4C, Pt-Ar o-Ph), 122.2 (s, 2C, Pt-Ar p-Ph), 121.4 (s,
2C, 4C, TtPh m-Ph). Anal. Calcd for C36H28N9OPPt: C, 52.18; H,
3.41; N, 15.21. Found: C, 52.35; H, 3.24; N, 15.07.
[(κ3-TtPh)PtMe2Et][X] (3b-L1). The procedure in general method A
was followed using ethyl iodide or ethyl triflate as the electrophile.
(κ2-TtCy)Pt(Ph)2 (2-L2). [Pt(Ph)2(SEt2)2]2 (0.061 g, 0.070 mmol)
and TtCy (0.035 g, 0.070 mmol) were placed in a Schlenk flask under
nitrogen. CH2Cl2 (10 mL) was added through the septum, and the
reaction mixture was stirred for 30 min at room temperature. After
removal of the solvent, the resulting oil was purified by flash
chromatography on alumina. The column was first flushed with ethyl
acetate and then by methanol. The methanol eluant was collected
and the solvent was removed by rotary evaporation to produce
(κ2-TtCy)Pt(Ph)2 (0.043 g, 0.051 mmol) as a white solid in 74% yield
(by TtCy ligand). 1H NMR (CD2Cl2, 291 K, δ): 8.96, 8.36 (s, 1H, 2H,
1
NMR data for the OTf counterion complex are reported. H NMR
(CD2Cl2, 300 K, δ): 9.18, 9.13 (s, 2H, 1H, TtPhCH), 7.84, 7.57
(m, 15H, TtPhC6H5), 2.41 (q, 2H, 2JPt−H = 75 Hz, Pt-CH2-CH3), 1.49
(s, 6H, 2JPt−H = 75 Hz, Pt-CH3), 0.87 (t, 3H, 3JPt−H = 56 Hz, Pt-CH2-
CH3). 31P{1H} NMR (CD2Cl2, 300 K, δ): −8.6 (s, 1P, TtPhPO).
1
13C {1H} NMR (CD2Cl2, 293 K, δ): 136.9 (d, 1C, OPC, JP−C
=
151 Hz), 136.7 (d, 2C, OPC, 1JP−C = 150 Hz), 136.2, 136.1 (s, 1C,
2C, ipso-Ph), 131.3, 131.2 (s, 2C, 1C, p-Ph), 131.0 (d, 2C, OPCCH,
2JP−C = 24 Hz), 130.8 (d, 1C, OPCCH, 2JP−C = 22 Hz), 130.6, 130.5
(s, 4C, 2C, o-Ph), 122.1, 122.0 (s, 2C, 4C, m-Ph), 16.0 (s, 1C, Pt-
3
3
TtCyCH), 7.04 (d, 4H, JPt−H = 63 Hz, JH−H = 7 Hz, Ho), 6.72−6.80
(m, 6H, Hm and Hp), 4.50 (m, 3H, NCHCy), 1.21−2.22 (m, 30H,
cyclohexyl). 31P{1H} NMR (CD2Cl2, 293 K, δ): −7.09 (s, 1P, TtCyP
O). 13C{1H} NMR (CD2Cl2, 292 K, δ): 141.7 (s, 2C, ipso-Ph), 139.1
2
1
CH2CH3, JPt−C = 33 Hz), 9.2 (s, 1C, Pt-CH2CH3, JPt−C = 681 Hz),
1
−4.1 (s, 2C, Pt-CH3, JPt−C = 725 Hz). Anal. Calcd for
C29H29F3N9O4PPtS: C, 39.46; H, 3.31; N, 14.28. Found: C, 39.16;
H, 3.17; N, 13.99.
1
(s, 4C, m-Ph), 139.1 (d, 1C, OPC, JP−C = 169 Hz), 138.1 (d, 2C,
[(κ3-TtCy)PtMe2Et][X] (3b-L2). The procedure in general method A
was followed using ethyl iodide or ethyl triflate as the electrophile.
1
2
OPC, JP−C = 149 Hz), 129.7 (d, 1C, OPCCH, JP−C = 33 Hz),
2
129.1 (d, 2C, OPCCH, JP−C = 24 Hz), 126.1 (s, 4C, o-Ph), 121.9
1
NMR data for the OTf counterion complex are reported. H NMR
(s, 2C, p-Ph), 62.4, 61.2 (s, 2C, 1C, CA), 33.8−33.1 (s, 1:1:1, 6C, CB),
25.4−25.1 (s, 1:1:1 and 2:1, 9C, CC and CD). HRMS (ESI) m/z
Calcd: 979.2265 (M + Cs+). Found: 979.2296. Anal. Calcd for
C36H49N9OPPt: C, 51.06; H, 5.47; N, 14.89. Found: C, 50.75; H, 5.54;
N, 14.62.
(CD2Cl2, 292 K, δ): 8.65, 8.60 (s, 2H, 1H, TtCyCH), 4.65 (m, 3H,
2
CA-H), 2.22 (q, 2H, JPt−H = 75 Hz, Pt-CH2-CH3), 2.24−1.30 (m,
2
30H, cyclohexyl), 1.31 (s, 6H, JPt−H = 75 Hz, Pt-CH3), 0.69 (s, 3H,
3JPt−H = 55 Hz, Pt-CH2-CH3). 31P{1H} NMR (CD2Cl2, 294 K, δ):
−7.7 (s, 1P, TtCyPO). 13C{1H} NMR (CD2Cl2, 292 K, δ): 136.0 (d,
1C, OPC, 1JP−C = 150 Hz), 135.9 (d, 2C, OPC, 1JP−C = 150 Hz),
Synthesis of [(κ3-TtPh)Pt(R′)2R″][X] Complexes. General
Method A. To a 50 mL Schlenk flask, κ2-TtRPt(R′)2 (0.030 mmol)
was placed under nitrogen. CH2Cl2 (10 mL) was added through the
septum, and the solution was treated with 1.3 equiv (0.045 mmol)
of the appropriate electrophilic reagent at room temperature. After
10 min, the solvent was evaporated, and the resulting oil was triturated
with pentane to afford the trialkyl platinum product as a light yellow
2
130.1 (d, 2C, OPCCH, JP−C = 25 Hz), 139.8 (d, 1C, OPCCH,
2JP−C = 25 Hz), 63.4 (s, 1C, 2C, CA) 33.6−33.5 (s, 1:1:1, 6C, CB),
2
25.3−25.2 (s, 1:1:1 and 2:1, 9C, CC and CD), 15.8 (s, 1C, JPt−C
=
33 Hz, Pt-CH2-CH3), 8.4 (s, 1C, 1JPt−C = 682 Hz, Pt-CH2-CH3), −4.9
(s, 2C, 1JPt−C = 726 Hz, Pt-CH3). Anal. Calcd for C29H47F3N9O4PPtS:
C, 38.66; H, 5.26; N, 13.99. Found: C, 38.42; H, 4.98; N, 13.87.
1
powder in quantitative yield by H NMR.
233
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237

Organometallics
Article
n
[(κ3-TtPh)PtMe2 Pr][I] (3c-L1). The procedure in general method A
4
4JPt−H = 21 Hz, JPt−H = 22 Hz, Pt-CH2C(CH3)⟩CH2), 3.27 (s, 2H,
2JPt−H = 96 Hz, Pt-Pt-CH2C(CH3)⟩CH2), 1.58 (s, 6H, 2JPt−H = 75 Hz,
Pt-CH3), 1.45 (s, 3H, 4JPt−H = 10 Hz, Pt-CH2C(CH3)⟩CH2). 31P{1H}
NMR (CD2Cl2, 292 K, δ): −7.0 (s, 1P, TtPhPO). 13C {1H} NMR
(CD2Cl2, 292 K, δ): 148.9 (s, 1C, 2JPt−C = 26 Hz, Pt-CH2CHCH2),
was followed using n-propyl iodide as the electrophile. The reaction
was stirred overnight instead of 10 min. 1H NMR (CD2Cl2, 300 K, δ):
9.52, 9.40 (s, 2H, 1H, TtPhCH), 7.89−7.58 (m, 15H, TtPhC6H5), 2.33
(t, 2H, 2JPt−H = 73 Hz, Pt-CH2-CH2-CH3), 1.58 (s, 6H, 2JPt−H = 74 Hz,
Pt-CH3), 1.30 (m, 2H, Pt-CH2-CH2-CH3), 0.80 (t, 3H, Pt-CH2-CH2-
136.9 (d, 1C, OPC, 1JP−C = 150 Hz), 136.4 (d, 2C, OPC, 1JP−C
=
CH3). 31P{1H} NMR (CD2Cl2, 300 K, δ): −9.8 (s, 1P, TtPhPO).
151 Hz), 136.0 (s, 3C, ipso-Ph), 131.4 (s, 2C, 1C, p-Ph), 130.7, 130.6
13C {1H} NMR (CD2Cl2, 300 K, δ): 136.5 (d, 1C, OPC, JP−C
=
1
2
(s, 4C, 2C, o-Ph), 130.5 (d, 2C, OPCCH, JP−C = 24 Hz), 121.8,
150 Hz), 136.4 (d, 2C, OPC, 1JP−C = 151 Hz), 136.4, 135.7 (s, 1C,
3
121.6 (s, 2C, 4C, m-Ph), 112.0 (s, 1C, JPt−C = 41 Hz, Pt-CH2CH
2
3
2C, ipso-Ph), 131.1 (d, 2C, OPCCH, JP−C = 24 Hz), 130.9, 130.8
CH2), 23.8 (s, 1C, JPt−C = 8 Hz, Pt-CH2C(CH3)CH2), 20.7
(s, 1C, 1JPt−C = 657 Hz, Pt-CH2C(CH3)CH2), −2.8 (s, 2C, Pt-CH3,
1JPt−C = 709 Hz). HRMS (ESI) m/z Calcd: 759.2037 (M+). Found:
759.2024.
(s, 2C, 1C, p-Ph), 130.3, 130.2 (s, 4C, 2C, o-Ph), 121.8, 121.6 (s, 1C,
2C, m-Ph), 23.9 (s, 1C, 3JPt−C = 29 Hz, Pt-CH2CH2CH3), 17.9 (s, 1C,
1JPt−C = 822 Hz, Pt-CH2CH2CH3), 15.4 (s, 1C, JPt−C = 80 Hz, Pt-
2
CH2CH2CH3), −4.6 (s, 2C, 1JPt−C = 723 Hz, Pt-CH3). Anal. Calcd for
C29H31IN9OPPt: C, 39.83; H, 3.57; N, 14.41. Found: C, 40.01; H,
3.47; N, 14.37.
[(κ3-TtCy)PtMe2(CH2C(CH3)CH2)][BF4] (3e-L2). The procedure in
general method B was followed using 3-bromo-isobutylene as the
1
electrophile. H NMR (CD2Cl2, 300 K, δ): 8.78, 8.72 (s, 2H, 1H,
n
4
4
[(κ3-TtCy)PtMe2 Pr][I] (3c-L2). The procedure in general method
TtCyCH), 4.92, 4.82 (s, 1H, 1H, JPt−H = 17 Hz, JPt−H = 18 Hz, Pt-
2
A was followed using n-propyl iodide as the electrophile. The reaction
was stirred overnight instead of 10 min. 1H NMR (CD2Cl2, 292 K, δ):
8.95, 8.88 (s, 2H, 1H, TtCyCH), 4.78 (m, 3H, CA-H), 2.13 (t, 2H,
2JPt−H = 72 Hz, Pt-CH2-CH2-CH3), 2.20−1.15 (m, 30H, cyclohexyl),
1.29 (s, 6H, 2JPt−H = 75 Hz, Pt-CH3), 0.70 (s, 3H, Pt-CH2-CH2-CH3).
31P{1H} NMR (CD2Cl2, 294 K, δ): −9.21 (s, 1P, TtCyPO). 13C{1H}
CH2C(Me)⟩CH2), 4.68 (m, 3H, CA-H), 3.18 (s, 2H, JPt−H = 94 Hz,
Pt-CH2C(CH3)⟩CH2), 2.37−1.41 (m, 30H, cyclohexyl), 1.42 (s, 6H,
2JPt−H = 73 Hz, Pt-CH3). 31P{1H} NMR (CD2Cl2, 292 K, δ): −4.1 (s,
1P, TtCyPO). 13C{1H} NMR (CD2Cl2, 293 K, δ): 154.4 (s, 1C, Pt-
1
CH2C(CH3)CH2), 135.0 (d, 1C, OPC, JP−C = 154 Hz), 134.9
(d, 2C, OPC, 1JP−C = 153 Hz), 130.5, 130.2 (d, 2C, 1C, OPCCH,
2JP−C = 24 Hz), 104.8 (s, 1C, Pt-CH2C(CH3)CH2), 63.5, 63.4
(s, 2C, 1C, CA), 33.5−33.2 (s, 1:1:1, 6C, CB), 25.2−25.0 (s, 1:1:1 and
2:1, 9C, CC and CD), 23.9 (s, 1C, Pt-CH2C(CH3)CH2), 19.6 (s, 1C,
1JPt−C = 663 Hz, Pt-CH2C(CH3)CH2), −3.1 (s, 2C, Pt-CH3,
1JPt−C = 697 Hz). HRMS (ESI) m/z Calcd: 777.3446 (M+). Found:
777.3412.
1
NMR (CD2Cl2, 292 K, δ): 135.5 (d, 1C, JP−C = 151 Hz, OPC),
1
2
135.3 (d, 2C, JP−C = 150 Hz, OPC), 130.3 (d, 2C, JP−C = 25 Hz,
2
OPCCH), 130.0 (d, 1C, JP−C = 25 Hz, OPCCH), 63.0 (s, 1C,
2C, CA), 33.4−33.3 (s, 1:1:1, 6C, CB), 25.3−24.9 (s, 1:1:1 and 2:1, 9C,
3
CC and CD), 23.8 (s, 1C, JPt−C = 28 Hz, Pt-CH2-CH2-CH3), 17.3 (s,
1
2
1C, JPt−C = 681 Hz, Pt-CH2-CH2-CH3), 15.5 (s, 1C, JPt−C = 77 Hz,
Pt-CH2-CH2-CH3), −5.2 (s, 2C, 1JPt−C = 722 Hz, Pt-CH3). Anal. Calcd
for C30H49IN9O4PPt: C, 39.02; H, 5.53; N, 14.12. Found: C, 38.84; H,
5.25; N, 14.24.
[(κ3-TtPh)PtMe2(CH2C6H5)][BF4] (3f-L1). The procedure in general
1
method A was followed using benzyl iodide as the electrophile. H
NMR (CD2Cl2, 292 K, δ): 9.20, 9.17 (s, 2H, 1H, TtPhCH), 7.83, 7.60
(m, 15H, TtPhC6H5), 6.96−6.84 (m, 5H, Pt-CH2-C6H5), 3.82 (s, 2H,
[(κ3-TtPh)PtMe2(CH2CHCH2)][I] (3d-L1). The procedure in
general method A was followed using allyl iodide as the electrophile.
1H NMR (CD2Cl2, 294 K, δ): 9.40, 9.36 (s, 2H, 1H, TtPhCH), 7.92,
7.61 (m, 15H, TtPhC6H5), 6.01 (m, 1H, Pt-CH2CHCH2), 5.10 (d,
1H, 3JH−H = 17 Hz, 4JPt−H = 20 Hz, Pt-CH2CHCHtrans), 4.91 (d, 1H,
2JPt−H = 93 Hz, Pt-CH2-C6H5), 1.61 (s, 6H, JPt−H = 74 Hz, Pt-CH3).
2
31P{1H} NMR (CD2Cl2, 292 K, δ): −7.73 (s, 1P, TtPhPO). 13C
{1H} NMR (CD2Cl2, 293 K, δ): 145.1 (s, 1C, JPt−C = 48 Hz, Pt-Bn
2
ipso-Ph), 136.9 (d, 1C, OPC, 1JP−C = 151 Hz), 136.0 (d, 2C, OP
C, 1JP−C = 152 Hz), 136.0, 135.9 (s, 1C, 2C, TtPh ipso-Ph), 131.3, 131.2
(s, 1C, 2C, TtPh p-Ph), 130.7 (d, 1C, 2C, OPCCH, 2JP−C = 21 Hz),
130.6, 130.5 (s, 2C, 4C, TtPh o-Ph), 129.6 (s, 2C, 3JPt−C = 21 Hz, Pt-Bn
3JH−H = 9 Hz, 4JPt−H = 20 Hz, Pt-CH2CH⟩CHs), 3.22 (d, 2H, 2JPt−H
=
2
96 Hz, Pt-CH2CH⟩CH2), 1.57 (s, 6H, JPt−H = 74 Hz, Pt-CH3).
31P{1H} NMR (CD2Cl2, 294 K, δ): −9.91 (s, 1P, TtPhPO). 13C{1H}
o-Ph), 128.2 (s, 2C, 4JPt−C = 12 Hz, Pt-Bn m-Ph), 125.4 (s, 1C, 5JPt−C
=
2
NMR (CD2Cl2, 293 K, δ): 141.5 (s, 1C, JPt−C = 54 Hz, Pt-CH2C
14 Hz, Pt-Bn p-Ph), 121.9, 121.7 (s, 2C, 4C, TtPh m-Ph), 17.8 (s, 1C,
1JPt−C = 658 Hz, Pt-CH2C6H5), −2.6 (s, 1C, 1JPt−C = 707 Hz, Pt-CH3).
HRMS (ESI) m/z Calcd: 795.2037 (M+). Found: 795.2012.
[(κ3-TtCy)PtMe2(CH2C6H5)][BF4] (3f-L2). The procedure in general
1
HCH2), 136.4 (d, 1C, OPC, JP−C = 150 Hz), 136.0 (d, 2C,
1
OPC, JP−C = 150 Hz), 135.6 (s, 3C, ipso-Ph), 131.0 (d, 1C, 2C,
2
OPCCH, JP−C = 24 Hz), 131.0 (s, 2C, 1C, p-Ph), 130.3, 130.2 (s,
3
4C, 2C, o-Ph), 121.7, 121.6 (s, 2C, 4C, m-Ph), 112.8 (s, 1C, JPt−C
=
1
1
method A was followed using benzyl iodide as the electrophile. H
51 Hz, Pt-CH2CHCH2), 15.7 (s, 1C, JPt−C = 656 Hz, Pt-CH2C
NMR (CD2Cl2, 292 K, δ): 8.58 (s, 3H, TtCyCH), 7.00−6.80 (m, 5H,
Pt-CH2-C6H5), 4.62, 4.48 (m, 1H, 2H, CA-H), 3.63 (s, 2H, 2JPt−H = 94
Hz, Pt-CH2-C6H5), 2.24−1.30 (m, 30H, cyclohexyl), 1.39 (s, 6H,
2JPt−H = 74 Hz, Pt-CH3). 31P{1H} NMR (CD2Cl2, 294 K, δ): −7.0 (s,
1P, TtCyPO). 13C{1H} NMR (CD2Cl2, 292 K, δ): 145.4 (s, 1C,
2JPt−C = 47 Hz, Pt-Bn ipso-Ph), 135.8 (d, 1C, OPC, 1JP−C = 150 Hz),
1
HCH2), −4.8 (s, 2C, Pt-CH3, JPt−C = 706 Hz). Anal. Calcd for
C29H29IN9OPPt: C, 39.92; H, 3.35; N, 14.45. Found: C, 39.64; H,
3.19; N, 14.19.
[(κ3-TtCy)PtMe2(CH2CHCH2)][I] (3d-L2). The procedure in general
method A was followed using allyl iodide as the electrophile. 1H NMR
(CD2Cl2, 292 K, δ): 8.87, 8.82 (s, 2H, 1H, TtCyCH), 5.85
3
4
1
(m, 1H, Pt-CH2CH⟩CH2), 4.90 (d, 1H, JH−H = 17 Hz, JPt−H = 18
Hz, Pt-CH2CH⟩CHtrans), 4.76 (m, 3H, CA-H), 3.00 (d, 2H, 2JPt−H = 96
Hz, Pt-CH2CH⟩CH2), 2.21−1.28 (m, 30H, cyclohexyl), 1.36 (s, 6H,
2JPt−H = 74 Hz, Pt-CH3). 31P{1H} NMR (CD2Cl2, 300 K, δ): −8.3 (s,
1P, TtCyPO). 13C{1H} NMR (CD2Cl2, 293 K, δ): 142.1 (s, 1C,
2JPt−C = 54 Hz, Pt-CH2CHCH2), 135.6 (d, 1C, OPC, 1JP−C = 150
Hz), 135.1 (d, 2C, OPC, 1JP−C = 150 Hz), 130.3, 130.1 (d, 2C, 1C,
135.0 (d, 2C, OPC, JP−C = 151 Hz), 129.7 (d, 3C, OPCCH,
2JP−C = 25 Hz), 129.4 (s, 2C, JPt−C = 21 Hz, Pt-Bn o-Ph), 128.1 (s,
3
4
5
2C, JPt−C = 13 Hz, Pt-Bn m-Ph), 124.9 (s, 1C, JPt−C = 14 Hz, Pt-Bn
p-Ph), 63.3, 63.2 (s, 1C, 2C, CA), 33.4−33.1 (s, 1:1:1, 6C, CB),
1
25.1−25.0 (s, 1:1:1 and 2:1, 9C, CC and CD), 16.9 (s, 1C, JPt−C
=
658 Hz, Pt-CH2C6H5), −3.5 (s, 2C, 1JPt−C = 706 Hz, Pt-CH3). HRMS
(ESI) m/z Calcd: 813.3446 (M+). Found: 813.3454.
[(κ3-TtPh)Pt(Ph)2Me][X] (4a-L1). The procedure in general method
A was followed using methyl iodide or methyl triflate as the
electrophile. NMR data for the OTf counterion complex are reported.
1H NMR (CD2Cl2, 292 K, δ): 9.25, 9.23 (s, 2H, 1H, TtPhCH),
2
3
OPCCH, JP−C = 24 Hz), 112.3 (s, 1C, JPt−C = 50 Hz, Pt-
1
CH2CHCH2), 15.2 (s, 1C, JPt−C = 656 Hz, Pt-CH2CHCH2),
63.2 (s, 1C, 2C, CA), 33.5−33.3 (s, 1:1:1, 6C, CB), 25.3−24.9 (s, 1:1:1
and 2:1, 9C, CC and CD), −4.1 (s, 2C, Pt-CH3, 1JPt−C = 706 Hz). Anal.
Calcd for C29H47IN9OPPt: C, 39.10; H, 5.32; N, 14.15. Found: C,
38.83; H, 5.25; N, 13.88.
7.80−7.57 (m, 15H, TtPhC6H5), 7.23 (d, 4H, JPt−H = 52 Hz, Pt-Ar
3
2
Ho), 7.07−6.98 (m, 6H, Pt-Ar Hm and Hp), 2.27 (s, 3H, JPt−H
=
[(κ3-TtPh)PtMe2(CH2C(CH3)CH2)][BF4] (3e-L1). The procedure in
general method B was followed using 3-bromo-isobutylene as the
electrophile. 1H NMR (CD2Cl2, 292 K, δ): 9.21, 9.17 (s, 2H,
1H, TtPhCH), 7.84, 7.62 (m, 15H, TtPhC6H5), 4.91, 4.85 (s, 1H, 1H,
74 Hz, Pt-CH3). 31P{1H} NMR (CD2Cl2, 295 K, δ): −10.1 (s, 1P,
TtPhPO). 13C{1H} NMR (CD2Cl2, 293 K, δ): 136.8 (d, 2C, 1JP−C
=
1
150 Hz, OPC), 136.5 (d, 1C, OPC, JP−C = 150 Hz), 136.1
(s, 4C, JPt−C = 10 Hz, Pt-Ar m-Ph), 135.8, 135.7 (s, 1C, 2C, TtPh
3
234
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237

Organometallics
Article
ipso-Ph), 131.5 (d, 2C, 2JP−C = 25 Hz, OPCCH), 131.1 (s, 3C, TtPh
2C, TtPh o-Ph), 128.5 (s, 2C, 1JPt−C = 951 Hz, Pt-Ar ipso-Ph), 127.3 (s,
2
2
p-Ph), 131.0 (d, 1C, JP−C = 24 Hz, OPCCH), 130.3, 130.2 (s, 2C,
4C, JPt−C = 56 Hz, Pt-Ar o-Ph), 125.2 (s, 2C, Pt-Ar p-Ph), 121.8,
4C, TtPh o-Ph), 127.9 (s, 2C, JPt−C = 944 Hz, Pt-Ar ipso-Ph), 127.2
121.7 (s, 2C, 4C, TtPh m-Ph), 115.4 (s, 1C, JPt−C = 49 Hz, Pt-
1
3
2
1
(s, 4C, JPt−C = 56 Hz, Pt-Ar o-Ph), 125.0 (s, 2C, Pt-Ar p-Ph), 122.0,
CH2CHCH2), 27.3 (s, 1C, JPt−C = 643 Hz, Pt-CH2CHCH2).
1
121.8 (s, 4C, 2C, TtPh m-Ph), 7.3 (s, 1C, JPt−C = 689 Hz, Pt-CH3).
HRMS (ESI) m/z Calcd: 869.2194 (M+). Found: 869.2152.
[(κ3-TtCy)Pt(Ph)2(CH2CHCH2)][BF4] (4c-L2). The procedure in
general method B was followed using allyl iodide as the electrophile.
1H NMR (CD2Cl2, 294 K, δ): 8.87, 9.30 (s, 2H, 1H, TtCyCH),
7.07−6.97 (m, 10H, Pt-C5H6), 5.80 (m, 1H, Pt-CH2CH⟩CH2), 5.10
Anal. Calcd for C38H31F3N9O4PPtS: C, 45.97; H, 3.15; N, 12.70.
Found: C, 45.72; H, 3.26; N, 12.48.
[(κ3-TtCy)Pt(Ph)2Me][X] (4a-L2). The procedure in general
method A was followed using methyl iodide or methyl triflate as the
electrophile. NMR data for the OTf counterion complex are reported.
1H NMR (CD2Cl2, 300 K, δ): 9.01, 9.00 (s, 2H, 1H, ThCyCH), 7.04
(d, 4H, 3JPt−H = 30 Hz, Ho), 7.02−6.93 (m, 6H, Hm and Hp), 4.65 (m,
3
4
(d, 1H, JH−H = 17 Hz, JPt−H = 19 Hz, Pt-CH2CH⟩CHtrans to H), 4.80
3
(d, 1H, JH−H = 9 Hz, Pt-CH2CH⟩CHs to H), 4.66, 4.59 (m, 2H, 1H,
CA-H), 3.71 (d, 2H, 2JPt−H = 87 Hz, Pt-CH2CH⟩CH2), 2.02−1.71 (m,
3H, NCH(Cy)), 2.20−1.27 (m, 30H, cyclohexyl), 2.07 (s, 3H, 2JPt−H
=
30H, cyclohexyl). 31P{1H} NMR (CD2Cl2, 294 K, δ): −6.3 (s, 1P,
74 Hz, Pt-CH3). 31P{1H} NMR (CD2Cl2, 300 K, δ): −8.3 (s, 1P,
TtPhPO). 13C{1H} NMR (CD2Cl2, 270 K, δ): 141.2 (s, 1C, 2JPt−C
=
TtCyPO). 13C{1H} NMR (CD2Cl2, 292 K, δ): 136.4 (s, 4C, 3JPt−C
=
64 Hz, Pt-CH2CHCH2), 136.0 (s, 4C, Pt-Ar m-Ph), 135.1 (d, 2C,
13 Hz, Pt-Ar m-Ph), 136.1 (d, 2C, OPC, 1JP−C = 150 Hz), 135.5 (d,
1
1
OPC, JP−C = 151 Hz), 134.8 (d, 1C, OPC, JP−C = 152 Hz),
1
2
2
1C, OPC, JP−C = 151 Hz), 130.9 (d, 3C, OPCCH, JP−C
=
130.5 (d, 2C, OPCCH, JP−C = 23 Hz), 130.3 (d, 1C, OPCCH,
1
2JP−C = 21 Hz), 128.3 (s, 2C, 1JPt−C = 944 Hz, Pt-Ar ipso-Ph), 127.3 (s,
23 Hz), 128.3 (s, 2C, JPt−C = 941 Hz, Pt-Ar ipso-Ph), 127.2 (s, 4C,
2JPt−C = 56 Hz, Pt-Ar o-Ph), 125.0 (s, 2C, Pt-Ar p-Ph), 63.6, 63.5 (s,
2C, 1C, NCH(cyclohexyl)), 33.3−33.0 (s, 1:1:1, 6C, CB), 25.1−25.0
2
4C, JPt−C = 55 Hz, Pt-Ar o-Ph), 125.2 (s, 2C, Pt-Ar p-Ph), 112.4 (s,
3
1C, JPt−C = 49 Hz, Pt-CH2CHCH2), 63.4, 63.3 (s, 2C, 1C, CA),
1
1
(s, 1:1:1 and 2:1, 9C, CC and CD), 6.5 (s, 1C, JPt−C = 689 Hz, Pt-
33.3−33.2 (s, 1:1:1, 6C, CB), 26.0 (s, 1C, JPt−C = 644 Hz, Pt-CH2C
CH3). HRMS (ESI) m/z Calcd: 861.3446 (M+). Found: 861.3465.
[(κ3-TtPh)Pt(Ph)2Et][X] (4b-L1). The procedure in general method A
was followed using ethyl iodide or ethyl triflate as the electrophile.
HCH2), 25.1−24.9 (s, 1:1:1 and 2:1, 9C, CC and CD). HRMS (ESI)
m/z Calcd: 887.3602 (M+). Found: 887.3564.
[(κ3-TtPh)Pt(Ph)2(CH2Ph)][BF4] (4d-L1). The procedure in general
1
1
NMR data for the OTf counterion complex are reported. H NMR
method B was followed using benzyl iodide as the electrophile. H
(CD2Cl2, 300 K, δ): 9.37, 9.25 (s, 2H, 1H, TtPhCH), 7.84−7.60
(m, 15H, TtPhC6H5), 7.20 (d, 4H, 3JPt−H = 51 Hz, Pt-Ar Ho), 7.07, 6.99
(m, 6H, Pt-Ar Hm and Hp), 3.17 (q, 2H, 2JPt−H = 70 Hz, Pt-CH2-CH3),
0.86 (t, 3H,3JPt−H = 54 Hz, Pt-CH2-CH3). 31P{1H} NMR (CD2Cl2,
295 K, δ): −10.5 (s, 1P, TtPhPO). 13C{1H} NMR (CD2Cl2, 293 K,
NMR (CD2Cl2, 296 K, δ): 9.35, 9.32 (s, 2H, 1H, TtPhCH), 7.72−7.51,
(m, 15H, TtPhC6H5), 7.28−7.03 (m, 10H, Pt-Ar), 6.83−6.72 (m, 5H,
Pt-CH2-C6H5), 4.51 (s, 2H, JPt−H = 88 Hz, Pt-CH2-C6H5). 31P{1H}
2
NMR (CD2Cl2, 296 K, δ): −7.06 (s, 1P, TtPhPO). 13C {1H} NMR
2
(CD2Cl2, 296 K, δ): 143.6 (s, 1C, JPt−C = 52 Hz, Pt-Bn ipso-Ph),
1
136.9 (d, 1C, OPC, 1JP−C = 151 Hz), 136.6 (d, 2C, OPC, 1JP−C
=
δ): 137.1 (d, 2C, OPC, JP−C = 149 Hz), 136.9 (d, 1C, OPC,
1JP−C = 152 Hz), 135.9 (s, 4C, Pt-Ar m-Ph), 135.7 (s, 3C, TtPh ipso-
151 Hz), 136.1 (s, 4C, Pt-Ar m-Ph), 135.9, 135.8 (s, 1C, 2C, TtPh ipso-
Ph), 131.1 (d, 2C, OPCCH, JP−C = 24 Hz), 131.1, 130.9 (s, 2C,
Ph), 131.3, 130.9 (s, 1C, 2C, TtPh p-Ph), 131.0 (d, 1C, 2C, OP
2
1C, TtPh p-Ph), 130.8 (d, 1C, OPCCH, 2JP−C = 24 Hz), 130.3, 130.2
CCH, JP−C = 25 Hz), 130.5, 130.4 (s, 2C, 4C, TtPh o-Ph), 130.1
2
(s, 4C, 2C, TtPh o-Ph), 128.6 (s, 2C, JPt−C = 907 Hz, Pt-Ar ipso-Ph),
(s, 2C, 3JPt−C = 24 Hz, Pt-Bn o-Ph), 128.4 (s, 2C, Pt-Bn m-Ph), 128.0
(s, 2C, Pt-Ar ipso-Ph), 127.5 (s, 4C, 2JPt−C = 54 Hz, Pt-Ar o-Ph), 126.4
1
2
127.1 (s, 4C, JPt−C = 57 Hz, Pt-Ar o-Ph), 124.9 (s, 2C, Pt-Ar p-Ph),
121.9, 121.8 (s, 4C, 2C, TtPh m-Ph), 22.3 (s, 1C, JPt−C = 665 Hz, Pt-
(s, 1C, JPt−C = 12 Hz, Pt-Bn p-Ph), 125.5 (s, 2C, Pt-Ar p-Ph), 121.7,
1
5
CH2-CH3), 16.8 (s, 1C, 2JPt−C = 43 Hz, Pt-CH2-CH3). Anal. Calcd for
C39H33F3N9O4PPtS: C, 46.52; H, 3.30; N, 12.52. Found: C, 46.24; H,
3.28; N, 12.29.
121.6 (s, 2C, 4C, TtPh m-Ph), 27.5 (s, 1C, JPt−C = 660 Hz, Pt-
1
CH2C6H5). HRMS (ESI) m/z Calcd: 919.2350 (M+). Found:
919.2314.
[(κ3-TtCy)Pt(Ph)2Et][X] (4b-L2). The procedure in general method A
was followed using ethyl iodide or ethyl triflate as the electrophile.
[(κ3-TtCy)Pt(Ph)2(CH2Ph)][BF4] (4d-L2). The procedure in general
1
method B was followed using benzyl iodide as the electrophile. H
1
NMR (CD2Cl2, 292 K, δ): 8.97, 8.87 (s, 2H, 1H, TtCyCH), 7.13−6.58
(m, 15H, Pt-CH2-C6H5 and Pt-C6H5), 4.64, 4.50 (m, 1H, 2H, CA-H),
NMR data for the OTf counterion complex are reported. H NMR
(CD2Cl2, 292 K, δ): 8.86, 8.77 (s, 2H, 1H, ThCyCH), 7.03−6.93 (m,
2
2
10H, Pt-C6H5), 4.63, 4.58 (m, 2H, 1H, CA-H), 2.94 (q, 2H, JPt−H
=
4.29 (s, 2H, JPt−H = 89 Hz, Pt-CH2-C6H5), 2.12−1.25 (m, 30H,
cyclohexyl). 31P{1H} NMR (CD2Cl2, 294 K, δ): −9.5 (s, 1P, TtCyP
67 Hz, Pt-CH2-CH3), 2.95−1.26 (m, 30H, cyclohexyl), 0.61 (s, 3H,
3JPt−H = 54 Hz, Pt-CH2-CH3). 31P{1H} NMR (CD2Cl2, 300 K, δ):
−7.2 (s, 1P, TtCyPO). 13C{1H} NMR (CD2Cl2, 292 K, δ): 136.3 (d,
2C, OPC, 1JP−C = 148 Hz), 136.2 (s, 4C, Pt-Ar m-Ph), 136.0 (d, 1C,
O). 13C{1H} NMR (CD2Cl2, 292 K, δ): 144.4 (s, 1C, JPt−C = 52 Hz,
2
Pt-Bn ipso-Ph), 136.3 (s, 4C, 3JPt−C = 7 Hz, Pt-Ar m-Ph), 135.9, 135.7
(d, 1C, 2C, OPC, 1JP−C = 148 Hz), 130.7, 130.6 (d, 3C, OPCCH,
2JP−C = 24 Hz), 130.0 (s, 2C, JPt−C = 24 Hz, Pt-Bn o-Ph), 128.4 (s,
3
1
2
OPC, JP−C = 150 Hz), 130.4 (d, 2C, OPCCH, JP−C = 24 Hz),
2
1
2C, 4JPt−C = 10 Hz, Pt-Bn m-Ph), 128.3 (s, 2C, 1JPt−C = 947 Hz, Pt-Ar
130.1 (d, 1C, OPCCH, JP−C = 25 Hz), 129.0 (s, 2C, JPt−C = 968
Hz, Pt-Ar ipso-Ph), 127.2 (s, 4C, 2JPt−C = 57 Hz, Pt-Ar o-Ph), 125.0 (s,
2C, Pt-Ar p-Ph), 63.4, 63.3 (s, 2C, 1C, CA), 33.3−33.2 (s, 1:1:1, 6C,
2
ipso-Ph), 127.3 (s, 4C, JPt−C = 55 Hz, Pt-Ar o-Ph), 126.0 (s, 1C,
5JPt−C = 12 Hz, Pt-Bn p-Ph), 125.2 (s, 2C, Pt-Ar p-Ph), 63.3, 63.2 (s,
CB), 25.1−24.9 (s, 1:1:1 and 2:1, 9C, CC and CD), 21.4 (s, 1C, 1JPt−C
=
1
1C, 2C, CA), 33.7−32.8 (s, 1:1:1, 6C, CB), 26.0 (s, 1C, JPt−C = 659
2
665 Hz, Pt-CH2-CH3), 16.9 (s, 1C, JPt−C = 43 Hz, Pt-CH2-CH3).
Hz, Pt-CH2C6H5), 25.0−24.9 (s, 1:1:1 and 2:1, 9C, CC and CD).
HRMS (ESI) m/z Calcd: 875.3602 (M+). Found: 875.3565.
HRMS (ESI) m/z Calcd: 937.3758 (M+). Found: 937.3724.
[(κ3-TtPh)Pt(Ph)2(CH2CHCH2)][BF4] (4c-L1). The procedure in
general method B was followed using allyl iodide as the electrophile.
1H NMR (CD2Cl2, 294 K, δ): 9.28, 9.30 (s, 2H, 1H, TtPhCH), 7.80,
7.58 (m, 15H, TtPhC6H5), 7.22 (d, 4H, 3JPt−H = 50 Hz, Pt-Ar Ho), 7.08,
7.02 (m, 6H, Pt-Ar Hm and Hp), 5.83 (m, 1H, Pt-CH2CH⟩CH2), 5.10
Synthesis of [(κ3-TtR)Pt(Me)2H][X] Complexes. [(κ3-TtPh)-
PtMe2H][BF4] (5-L1). Into a 50 mL Schlenk flask was placed
κ2-TtPhPt(CH3)2 (0.021 g, 0.030 mmol) under nitrogen. CH2Cl2
(10 mL) was added through the septum, and the flask was cooled
to −78 °C. The solution was then treated with 1.0 equiv (3.7 μL, 0.030
mmol) of ca. 8.0 M HBF4·Et2O, and it was allowed to warm to room
temperature. The solvent was evaporated and the resulting solid was
triturated with pentane to afford [(κ3-TtPh)Pt(Me)2H][BF4] (0.023 g,
3
4
(d, 1H, JH−H = 19 Hz, JPt−H = 18 Hz, Pt-CH2CH⟩CHtrans to H), 4.92
(d, 1H, 3JH−H = 10 Hz, 4JPt−H = 15 Hz, Pt-CH2CH⟩CHs to H), 3.90 (d,
2H, 2JPt−H = 86 Hz, Pt-CH2CH⟩CH2). 31P{1H} NMR (CD2Cl2, 270 K,
δ): −8.0 (s, 1P, TtPhPO). 13C{1H} NMR (CD2Cl2, 293 K, δ): 140.9
1
0.029 mmol) as a white powder. H NMR (CD2Cl2, 294 K, δ): 9.30
(s, 2H, 1H, TtPhCH), 7.85−7.24 (m, 15H, TtPhC6H5), 1.60 (s, 6H,
2
(s, 1C, JPt−C = 65 Hz, Pt-CH2CHCH2), 136.8 (d, 2C, OPC,
1
2JPt−H = 70 Hz, Pt-CH3), −19.91 (s, 1H, JPt−H = 1541 Hz, Pt-H).
1JP−C = 150 Hz), 136.7 (d, 1C, OPC, 1JP−C = 150 Hz), 136.1 (s, 4C,
31P{1H} NMR (CD2Cl2, 300 K, δ): −6.6 (s, 1P, TtPhPO). 13C {1H}
Pt-Ar m-Ph), 135.7 (s, 3C, TtPh ipso-Ph), 131.2, 131.1 (s, 2C, 1C, TtPh
2
1
p-Ph), 130.9 (d, 3C, OPCCH, JP−C = 24 Hz), 130.5, 130.4 (s, 4C,
NMR (CD2Cl2, 293 K, δ): 135.7 (d, 2C, OPC, JP−C = 152 Hz),
235
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237

Organometallics
Article
1
135.6, 135.5 (s, 1C, 2C, TtPh ipso-Ph), 135.4 (d, 1C, OPC, JP−C
=
(CD2Cl2, 293 K, δ): 136.4 (d, 2C, 1JP−C = 152 Hz, OPC), 135.2 (d,
1
2
150 Hz), 130.9 (d, 2C, OPCCH, 2JP−C = 24 Hz), 130.7 (s, 3C, TtPt
1C, JP−C = 150 Hz, OPC), 130.3 (d, 1C, JP−C = 24 Hz, OP
2
p-Ph), 130.1 (s, 6C, TtPh o-Ph), 121.5 (s, 6C, TtPh m-Ph), −14.6
CCH), 129.9 (d, 1C, JP−C = 25 Hz, OPCCH), 63.2, 63.0 (s, 1C,
1
1
(s, 2C, Pt-CH3, JPt−C = 620 Hz).
2C, CA), 37.1 (s, 2C, JPt−C = 361 Hz, Pt-C2H4), 33.5−33.3 (s, 1:1:1,
[(κ3-TtPh)PtMe2H][BAr′4] ([5-L1][BAr′4]). Into a 50 mL Schlenk flask
was placed κ2-TtPhPt(CH3)2 (0.021 g, 0.030 mmol) under nitrogen.
CH2Cl2 (10 mL) was added through the septum, and the flask was
cooled to −78 °C. The platinum complex was treated with a methylene
chloride solution containing 1.0 equiv (0.023 g, 0.030 mmol) of HBAr′4
via cannula transfer. The mixture was allowed to warm to room
temperature, and the solvent was concentrated to ca. 1 mL. Slow
diffusion of hexanes produced clear, hexagonal crystals. Anal. Calcd for
C58H37BF24N9OPPt: C, 44.40; H, 2.38; N, 8.04. Found: C, 44.08; H,
2.44; N, 8.16.
6C, CB), 25.2−25.0 (s, 1:1:1 and 2:1, 9C, CC and CD), −13.3 (s, 1C,
1JPt−C = 620 Hz, Pt-CH3). HRMS (ESI) m/z Calcd: 735.2976 (M+).
Found: 735.2953.
[(κ3-TtPh)PtMe(η2-propylene)][BF4] (7b-L1). Yield: 77% by 1H
1
NMR. H NMR (CD2Cl2, 300 K, δ): 9.34, 9.21, 9.19 (s, 1H, 1H, 1H,
TtPhCH), 7.89, 7.59 (m, 15H, TtPhC6H5), 5.03 (m, 1H, H2CC
3
HCH3), 4.35 (d, 1H, JH−H = 13 Hz, Htrans to HCCHCH3), 4.28 (d,
1H, 3JH−H = 7 Hz, Hs to HCCHCH3), 1.51 (d, 3H, 3JH−H = 6 Hz, Pt-H2
2
CCHCH3), 0.95 (s, 3H, JPt−H = 63 Hz, Pt-CH3). 31P{1H} NMR
(CD2Cl2, 300 K, δ): −9.8 (s, 1P, TtPhPO). 13C {1H} NMR (CD2Cl2,
293 K, δ): 136.0, 135.8 (s, 3C, TtPh ipso-Ph), 131.9 (d, 2C, OPCCH,
2JP−C = 24 Hz), 131.4, (s, 3C, TtPh p-Ph), 130.6 (s, 6C, TtPh o-Ph),
121.7, 121.6 (s, 4C, 2C, TtPh m-Ph), 88.7 (s,1C, H2CCHCH3), 64.6
(s, 1C, H2CCHCH3), 20.0 (s, 1C, H2CCHCH3), −8.6 (s, 1C, Pt-
CH3). HRMS (ESI) m/z Calcd: 731.1724 (M+). Found: 731.1691.
[(κ3-TtPh)PtMe(η2-s-2-butene)][BF4] (7c-L1). Yield: 78% by 1H
NMR. 1H NMR (CD2Cl2, 298 K, δ): 9.40, 9.27 (s, 2H, 1H, TtPhCH),
7.87, 7.49 (m, 15H, TtPhC6H5), 5.02 (d, 2H, (CH3)HCCH(CH3)),
1.59 (d, 6H, (CH3)HCCH(CH3)), 0.68 (s, 3H, Pt-CH3). 31P{1H}
NMR (CD2Cl2, 298 K, δ): −7.3 (s, 1P, TtPhPO). 13C {1H} NMR
(CD2Cl2, 298 K, δ): 136.1, 135.9 (s, 1C, 2C, TtPh ipso-Ph), 132.0
(d, 2C, OPCCH, 2JP−C = 29 Hz), 131.4−130.3 (s, 9C, TtPh o-Ph and
p-Ph), 121.9−121.6 (s, 6C, TtPh m-Ph), 87.0 (s, 2C, (CH3)HC
CH(CH3)), 14.2 (s, 2C, (CH3)HCCH(CH3)), −1.8 (s, 1C, Pt-
CH3). HRMS (ESI) m/z Calcd: 745.1881 (M+). Found: 745.1851.
[(κ3-TtPh)PtMe(η2-trans-2-butene)][BF4] (7d-L1). Yield: 74% by 1H
NMR. 1H NMR (CD2Cl2, 270 K, δ): 9.38, 9.21, 9.11 (s, 1H, 1H, 1H,
TtPhCH), 7.88, 7.62 (m, 15H, TtPhC6H5), 5.48, 4.71 (m, 1H, 1H,
(CH3)HCCH(CH3)), 1.82, 1.30 (d, 3H, 3H, (CH3)HCC
[(κ3-TtCy)PtMe2H][BF4] (5-L2). The same procedure was performed
using the analgous TtCyPt(CH3)2 complex. 1H NMR (CD2Cl2, 292 K,
δ): 8.88, 8.87 (s, 1H, 2H, TtCyCH), 4.62 (m, 3H, CA-H), 2.20−1.22
(m, 30H, cyclohexyl), 1.39 (s, 6H, 2JPt−H = 70 Hz, Pt-CH3), −20.07 (s,
1H, 1JPt−H = 1519 Hz, Pt-H). 31P{1H} NMR (CD2Cl2, 292 K, δ): −5.6
(s, 1P, TtCyPO). 13C{1H} NMR (CD2Cl2, 293 K, δ): 134.6 (d, 2C,
1
1
OPC, JP−C = 150 Hz), 134.2 (d, 1C, OPC, JP−C = 150 Hz),
130.6 (d, 3C, OPCCH, 2JP−C = 24 Hz), 63.0 (s, 3C, CA), 33.0−32.8
(s, 1:1:1, 6C, CB), 24.9−24.6 (s, 1:1:1 and 2:1, 9C, CC and CD), −15.6
1
(s, 2C, Pt-CH3, JPt−C = 623 Hz).
Elimination and Trapping Reactions. In a typical experiment, a
Schlenk flask was charged with 0.030 mmol of [(κ3-TtR)Pt(Me)2H]-
[BF4] 5 under nitrogen. CH2Cl2 (6 mL) was added through the
septum, and the flask was warmed to 35 °C. The headspace was
purged with the trapping gas (L) and stirred for 2 h (L = CO or
olefin). The solvent was evaporated and the resulting oil was triturated
with pentane to produce [TtRPt(Me)(L)][BF4] as a light yellow
1
powder in good yield by H NMR.
[(κ3-TtPh)PtMe(CO)][BF4] (6-L1). Yield: 86% by H NMR. H NMR
1
1
(CD2H2, 293 K, δ): 9.29 (s, 3H, TtPhCH), 7.88, 7.56 (m, 15H, TtPh-
2
H(CH3)), 0.98 (s, 3H, JPt−H = 64 Hz, Pt-CH3). 31P{1H} NMR
C6H5), 1.44 (s, 3H, JPt−H = 74 Hz, Pt-CH3). 31P{1H} NMR (CD2Cl2,
2
(CD2Cl2, 270 K, δ): −9.5 (s, 1P, TtPhPO). 13C {1H} NMR
(CD2Cl2, 270 K, δ): 139.2 (d, 1C, 1JP−C = 164 Hz, OPC), 137.1 (d,
1C, 1JP−C = 150 Hz, OPC), 137.0 (d, 1C, 1JP−C = 146 Hz, OPC),
135.8, 135.7, 135.7 (s, 1C, 1C, 1C, TtPh ipso-Ph), 132.6 (d, 1C, OP
CCH, 2JP−C = 26 Hz), 132.1 (d, 1C, OPCCH, 2JP−C = 25 Hz), 131.0
(d, 1C, OPCCH, 2JP−C = 30 Hz), 131.2−130.3 (s, 9C, TtPh o-Ph and
p-Ph), 121.7, 121.6, 121.0 (s, 2C, 2C, 2C, TtPh m-Ph), 90.1, 90.0 (s,
1C, 1C, (CH3)HCCH(CH3)), 19.7 (s, 2C, (CH3)HCCH(CH3)),
−7.6 (s, 1C, Pt-CH3). HRMS (ESI) m/z Calcd: 745.1881 (M+).
Found: 745.1833.
282 K, δ): −7.8 (s, 1P, TtPhPO). 13C {1H} NMR (CD2Cl2, 284 K, δ):
161.3 (s, 1C, Pt-CO), 135.9, 135.6 (s, 2C, 1C, TtPh ipso-Ph), 132.3 (d,
2
2
1C, JP−C = 26 Hz, OPCCH), 131.4 (d, 2C, JP−C = 24 Hz, OP
CCH), 131.0 (s, 3C, TtPt p-Ph), 130.6, 130.4 (s, 2C, 4C, TtPh o-Ph),
121.9, 121.6 (s, 2C, 4C TtPh m-Ph), −14.6 (s, 1C, Pt-CH3). IR (CH2Cl2
solution) νCO = 2124 cm−1. Anal. Calcd for C26H21BF4N9O2PPt: C,
38.82; H, 2.63; N, 15.67. Found: C, 38.77; H, 2.91; N, 15.39.
[(κ3-TtCy)PtMe(CO)][BF4] (6-L2). Yield: 85% by 1H NMR. 1H NMR
(CD2Cl2, 292 K, δ): 8.73 (s, 3H, TtCyCH), 4.63 (m, 3H, CA-H),
2.24−1.25 (m, 30H, cyclohexyl), 1.41 (s, 6H, 2JPt−H = 71 Hz, Pt-CH3).
31P{1H} NMR (CD2Cl2, 292 K, δ): −8.6 (s, 1P, TtCyPO). 13C{1H}
[(κ3-TtPh)PtMe(η2-isobutylene)][BF4] (7e-L1). Yield: 78% by 1H
NMR. 1H NMR (CD2Cl2, 298 K, δ): 9.29, 9.17 (s, 2H, 1H, TtPhCH),
7.87, 7.56 (m, 15H, TtPhC6H5), 4.53 (s, 2H, 2JPt−H = 67 Hz, H2CC(
CH3)2), 1.52 (s, 6H, H2CC(CH3)2), 1.07 (s, 3H, Pt-CH3). 31P{1H}
NMR (CD2Cl2, 298 K, δ): −8.7 (s, 1P, TtPhPO). 13C {1H} NMR
NMR (CD2Cl2, 292 K, δ): 161.8 (s, 1C, Pt-CO), 136.9 (d, 3C, 1JP−C
=
157 Hz, OPC), 132.0 (d, 2C, 2JP−C = 29 Hz, OPCCH), 130.1 (d,
1C, 2JP−C = 24 Hz, OPCCH), 63.7, 63.0 (s, 1C, 2C, CA), 33.4−33.2
(s, 6C, CB), 25.2−25.0 (s, 1:1:1 and 2:1, 9C, CC and CD), −15.3 (s,
1C, 1JPt−C = 522 Hz, Pt-CH3). IR (CH2Cl2 solution) νCO = 2117 cm−1.
HRMS (ESI) m/z Calcd: 735.2612 (M+). Found: 735.2657. Anal.
Calcd for C26H39BF4N9O2PPt: C, 37.97; H, 4.78; N, 15.33. Found: C,
37.97; H, 4.78; N, 15.33.
1
(CD2Cl2, 298 K, δ): 138.3 (d, 2C, JP−C = 156 Hz, OPC), 137.6
1
(d, 1C, JP−C = 156 Hz, OPC), 135.9 (s, 3C, TtPh ipso-Ph), 132.3
2
(d, 3C, OPCCH, JP−C = 24 Hz), 131.3, 130.9 (s, 1C, 2C, TtPh p-
Ph), 130.6, 130.2 (s, 4C, 2C, TtPh o-Ph), 121.7 (s, 6C, TtPh m-Ph),
110.5 (s, 1C, H2CCH(CH3)2), 67.6 (s, 1C, H2CCH(CH3)2),
28.5 (s, 1C, H2CCH(CH3)2), −5.3 (s, 1C, Pt-CH3). HRMS (ESI)
m/z Calcd: 745.1881 (M+). Found: 731.1875.
[(κ3-TtPh)PtMe(η2-C2H4)][BF4] (7a-L1). Yield: 85% by H NMR. H
1
1
NMR (CD2Cl2, 298 K, δ): 9.39, 9.34 (s, 2H, 1H, TtPhCH), 7.84−7.44
(m, 15H, TtPhC6H5), 3.33 (s, 4H, JPt−H = 79 Hz, Pt-C2H4), 1.05 (s,
2
Structural Data for [3a-L1][BAr′4]. Crystals were obtained from
CH2Cl2/hexanes: C60H41BCl2F24N9OPPt, M = 1667.79; monoclinic,
space group P21/c; Z = 4; a = 16.2833(2) Å, b = 15.5893(2) Å,
c = 25.8409(2) Å; α = 90°, β = 93.93700(10)°, γ = 90°; U =
6543.85(14) Å3; Dc = 1.693 mg/cm3; T = 100(2) K; θ range =
2.72−70.06°; reflections collected = 129 300; independent reflections =
12 190; data were collected on a Bruker-AXS SMART Apect-II diffracto-
meter; goodness-of-fit = 1.073.
3H, JPt−H = 63 Hz, Pt-CH3), 31P {1H} NMR (CD2Cl2, 300 K, δ):
2
−7.6 (s, 1P, TtPhPO). 13C {1H} NMR (CD2Cl2, 293 K, δ): 137.2 (d,
1C, OPC, 1JP−C = 153 Hz), 136.7 (d, 2C, 1JP−C = 150 Hz, OPC),
135.6, 135.5 (s, 2C, 1C, TtPh ipso-Ph), 131.1, 130.9 (s, 1C, 2C, TtPt
p-Ph), 130.3 (s, 6C, TtPh o-Ph), 121.4, 121.3 (s, 4C, 2C, TtPh m-Ph),
40.9 (s, 2C, Pt-C2H4), −12.3 (s, 1C, Pt-CH3). Anal. Calcd for
C59H37BF24N9OPPt (BAr′4 counterion): C, 44.83; H, 2.36; N, 7.97.
Found: C, 45.11; H, 2.38; N, 7.69.
[(κ3-TtCy)PtMe(η2-C2H4)][BF4] (7a-L2). Yield: 81% by H NMR. H
NMR (CD2Cl2, 292 K, δ): 8.69, 8.62 (s, 2H, 1H, TtCyCH), 4.63, 4.54
(m, 2H, 1H, CA-H), 3.00 (s, 4H, 2JPt−H = 81 Hz, Pt-C2H4) 2.23−1.25
1
1
ASSOCIATED CONTENT
■
S
* Supporting Information
Representative 1H and 13C NMR spectra, kinetic studies data of
(m, 30H, cyclohexyl), 0.85 (s, 6H, JPt−H = 63 Hz, Pt-CH3). 31P{1H}
2
NMR (CD2Cl2, 292 K, δ): −7.7 (s, 1P, TtCyPO). 13C{1H} NMR
biphenyl formation from 4c-L2, and cif file for structure 3a-L1.
236
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237

Organometallics
Article
(33) Khusnutdinova, J. R.; Newman, L. L.; Zavalij, P. Y.; Lam, Y.-F.;
Vedernikov, A. N. J. Am. Chem. Soc. 2008, 130, 2174.
(34) Khusnutdinova, J. R.; Zavalij, P. Y.; Vedernikov, A. N. Can. J.
Chem. 2009, 87, 110.
(35) Oloo, W.; Zavalij, P. Y.; Zhang, J.; Khaskin, E.; Vedernikov, A. N.
J. Am. Chem. Soc. 2010, 132, 14400.
This material is available free of charge via the Internet at
http://pubs.acs.org.
ACKNOWLEDGMENTS
■
We thank the National Science Foundation (Grant CHE-
1058675) for support of this research.
(36) Zhang, F.; Broczkowski, M. E.; Jennings, M. C.; Puddephatt, R.
J. Can. J. Chem. 2005, 83, 595.
(37) Rostovtsev, V. V.; Green, L. G.; Fokin, V. V.; Sharpless, K. B.
Angew. Chem., Int. Ed. 2002, 41, 2596.
REFERENCES
■
(1) Slone, C. S.; Weinberger, D. A.; Mirkin, C. A. Prog. Inorg. Chem.
1999, 48, 233.
(38) Diez-Gonzalez, S. Catal. S. Technol. 2011, 1, 166.
(39) Meldal, M.; Tornoe, C. W. Chem. Rev. 2008, 108, 2952.
(40) van Assema, S. G. A.; Tazelaar, C. G. J.; Bas de Jong, G.;
van Maarseveen, J. H.; Schakel, M.; Lutz, M.; Spek, A. L.; Slootweg, J.
C.; Lammertsma, K. Organometallics 2008, 27, 3210.
(41) Schulze, B.; Friebe, C.; Hager, M. D.; Winter, A.; Hoogenboom,
R.; Gorls, H.; Schubert, U. S. Dalton Trans. 2009, 787.
(42) Li, Y.; Huffman, J. C.; Flood, A. H. Chem. Commun. 2007, 2692.
(43) Meudtner, R. M.; Ostermeire, M.; Goddard, R.; Limberg, C.;
Hecht, S. Chem.Eur. J. 2007, 13, 9834.
(2) Braunstein, P.; Naud, F. Angew. Chem., Int. Ed. 2001, 40, 680.
(3) Trofimenko, S. Scorpionates: The Coordination Chemistry of
Polypyrazolylborate Ligands; Imperial College Press: London, 1999.
(4) Zhang, J.; Leitus, G.; Ben-David, Y.; Milstein, D. J. Am. Chem. Soc.
2005, 127, 10840.
(5) Lindner, R.; van den Bosch, B.; Lutz, M.; Reek, J. N. H.; van der Vlugt,
J. I. Organometallics 2011, 30, 499.
(6) Lee, H. M.; Lee, C.-C.; Cheng, P.-Y. Curr. Org. Chem. 2007, 11,
1491.
(7) Vedernikov, A. N.; Binfield, S. A.; Zavalij, P. Y.; Khusnutdinova,
J. R. J. Am. Chem. Soc. 2006, 128, 82.
(8) Rybtchinski, B.; Oevers, S.; Montag, M.; Vigalok, A.; Rozenberg,
H.; Martin, J. M. L.; Milstein, D. J. Am. Chem. Soc. 2001, 123, 9064.
(9) Fulmer, G. R.; Kaminsky, W.; Kemp, R. A.; Goldberg, K. I.
Organometallics 2011, 30, 1627.
(10) Abel, E. W.; Kite, K.; Perkins, P. S. Polyhedron 1987, 6, 549.
(11) Goldberg, K. I.; Yan, J.; Breitung, E. M. J. Am. Chem. Soc. 1995,
117, 6889.
(12) Williams, B. S.; Holland, A. W.; Goldberg, K. I. J. Am. Chem. Soc.
1999, 121, 252.
(13) Crumpton, D. M.; Goldberg, K. I. J. Am. Chem. Soc. 2000, 122,
962.
(14) Lan, M. P.; Remy, M. S.; Lao, D. B.; Sanford, M. S.; Mayer, J. M.
Organometallics 2011, 30, 3704.
(44) Fletcher, J. T.; Bumgarner, B. J.; Engels, N. D.; Skoglund, D. A.
Organometallics 2008, 27, 5430.
(45) Beyer, B.; Ulbricht, C.; Escudero, D.; Friebe, C.; Winter, A.;
Gonzales, L.; Schubert, U. S. Organometallics 2009, 28, 5478.
(46) Crowley, J. D.; Bandeen, P. H. Dalton Trans. 2010, 612.
(47) Yang, W.-W.; Wang, L.; Zhong, Y.-W.; Yao, J. Organometallics
2011, 30, 2236.
(48) Procelewska, J.; Zahl, A.; Liehr, G.; van Eldik, R.; Smythe, N. A.;
Williams, B. S.; Goldberg, K. I. Inorg. Chem. 2005, 44, 7732.
(49) Zhang, F.; Kirby, C. W.; Hairsine, D. W.; Jennings, M. C.;
Puddephatt, R. J. J. Am. Chem. Soc. 2005, 127, 14196.
(50) Reinartz, S.; Brookhart, M.; Templeton, J. L. Organometallics
2002, 21, 247.
(51) Abo-Amer, A.; Puddephatt, R. J. Inorg. Chem. Commun. 2011,
14, 111.
(52) Scollard, J. D.; Day, M.; Labinger, J. A.; Bercaw, J. E. Helv. Chim.
Acta 2001, 84, 3247.
(53) Fekl, U.; van Eldik, R.; Lovell, S.; Goldberg, K. I. Organometallics
2000, 19, 3535.
(15) Goldberg, K. I.; Yan, J.; Winter, E. L. J. Am. Chem. Soc. 1994,
116, 1573.
(16) Brown, M. P.; Puddephatt, R. J.; Upton, C. E. E. J. Chem. Soc.,
Dalton Trans. 1974, 2457.
(17) Puddephatt, R. J. Angew. Chem., Int. Ed. 2002, 41, 261.
(18) Fekl, U.; Kaminsky, W.; Goldberg, K. I. J. Am. Chem. Soc. 2001,
123, 6423.
(19) Reinartz, S.; White, P. S.; Brookhart, M.; Templeton, J. L. J. Am.
Chem. Soc. 2001, 123, 6425.
(54) Byers, P. K.; Canty, A. J.; Skelton, B. W.; White, A. H.
Organometallics 1990, 9, 826.
(55) O’Reilly, S. A.; White, P. S.; Templeton, J. L. J. Am. Chem. Soc.
1996, 118, 5684.
(56) Neuhaus, D. The Nuclear Overhauser Effect in Structural and
Conformational Analysis; Wiley-VCH: New York, 2000.
(57) Shilov, A. E.; Shul’pin, G. B. Chem. Rev. 1997, 2897.
(58) Brookhart, M.; Green, M. L. H. J. Organomet. Chem. 1983, 250,
395.
(59) Fulmer, G. R.; Miller, A. J.; Sherden, N. H.; Gottlieb, H. E.;
Nudelman, A.; Stoltz, B. M.; Bercaw, J. E.; Goldberg, K. I.
Organometallics 2010, 29, 2176.
(60) Reinartz, S.; White, P. S.; Brookhart, M.; Templeton, J. L.
Organometallics 2000, 19, 3854.
(61) Braterman, P. S.; Cross, R. J.; Young, G. B. J. Chem. Soc., Dalton
Trans. 1977, 1892.
(62) Pangborn, A. B.; Giardello, M. A.; Grubbs, R. H.; Rosen, R. K.;
Timmers, F. J. Organometallics 1996, 15, 1518.
(63) Scott, J. D.; Puddephatt, R. J. Organometallics 1983, 2, 1643.
(64) Steele, B.; Vrieze, K. Transition Met. Chem. 1977, 2, 140.
(65) Brookhart, M.; Grant, B.; Volpe, A. F. Organometallics 1992, 11,
3290.
(66) Hoang, C. T.; Bouillere, F.; Johannesen, S.; Zulauf, A.; Panel, C.;
Pourilhes, A.; Gori, D.; Alezra, V.; Kouklovsky, C. J. Org. Chem. 2009,
74, 4177.
(20) Oblad, P. F.; Bercaw, J. E.; Hazari, N.; Labinger, J. A. Organo-
metallics 2010, 29, 789.
(21) Jensen, M. P.; Wick, D. D.; Reinartz, S.; White, P. S.;
Templeton, J. L.; Goldberg, K. J. Am. Chem. Soc. 2003, 125, 8614.
(22) Kostelansky, C. N.; MacDonald, M. G.; White, P. S.;
Templeton, J. L. Organometallics 2006, 25, 2993.
(23) West, N. M.; Reinartz, S.; White, P. S.; Templeton, J. L. J. Am.
Chem. Soc. 2006, 128, 2059.
(24) MacDonald, M. G.; Kostelansky, C. N.; White, P. S.; Templeton,
J. L. Organometallics 2006, 25, 4560.
(25) Engelman, K. L.; White, P. S.; Templeton, J. L. Inorg. Chim. Acta
2009, 362, 4461.
(26) Engelman, K. L.; White, P. S.; Templeton, J. L. Organometallics
2010, 29, 4943.
(27) West, N.; Templeton, J. L. Unpublished work.
(28) Vedernikov, A. N.; Fettinger, J. C.; Mohr, F. J. Am. Chem. Soc.
2004, 126, 11160.
(29) Khusnutdinova, J. R.; Maiorana, A. S.; Zavalig, P. Y.;
Vedernikov, A. N. Inorg. Chim. Acta 2011, 369, 274.
(30) Khusnutdinova, J. R.; Zavalij, P. Y.; Vedernikov, A. N. Organo-
metallics 2007, 26, 2402.
(67) Demko, Z. P.; Sharpless, K. B. Angew. Chem., Int. Ed. 2002, 41,
2110.
(31) Khusnutdinova, J. R.; Zavalij, P. Y.; Vedernikov, A. N. Organo-
metallics 2007, 26, 3466.
(32) Khusnutdinova, J. R.; Zavalij, P. Y.; Vedernikov, A. N. Organo-
metallics 2011, 30, 3392.
237
dx.doi.org/10.1021/om2007997 | Organometallics 2012, 31, 225−237