Synthesis and reactivity of platinum vinylcarbene complexes prepared from activation of propargyl alcohols

Article abstract of DOI:10.1016/j.jorganchem.2018.10.016

Platinum vinylcarbene complexes are potentially useful for organometallic synthesis and catalysis, but have been rarely studied. This work reports a convenient route to make platinum vinylcarbene complexes. Treatment of [PtCl₂(PPh₃)]₂ with propargyl alcohols HC≡CC(OH)RR’ (RR’ = Ph₂, cyclo-C₆H₁₀(OH), (iPr)(C≡CTMS) and (H)(Ph)) in the presence of EtOH produced the vinylcarbene complexes trans-PtCl₂{ = C(OEt)-CH=CRR’}(PPh₃). Under similar condition, [PtCl₂(PPh₃)]₂ reacted with HC≡CC(OH)Me₂ to give cis-PtCl₂{ = C(OEt)-CH=CMe₂}(PPh₃). Complex trans-PtCl₂{ = C(OEt)-CH=CPh₂}(PPh₃) readily undergo a metathesis reaction with NaI to give trans-PtI₂{ = C(OEt)-CH=CPh₂}(PPh₃) which can isomerize to cis-PtI₂{ = C(OEt)-CH=CPh₂}(PPh₃). Complex trans-PtCl₂{ = C(OEt)-CH=CPh₂}(PPh₃) reacted with PPh₃ to give EtCl and the acyl complex trans-PtCl{C(O)CH=CPh₂}(PPh₃)₂, which can undergo a decarbonylation reaction to give PtCl(CH=CPh₂)(PPh₃)_2.

Full text of DOI:10.1016/j.jorganchem.2018.10.016

Accepted Manuscript
Synthesis and reactivity of platinum vinylcarbene complexes prepared from activation
of propargyl alcohols
Wenqing Ruan, Chuan Shi, Herman H.Y. Sung, Ian D. Williams, Guochen Jia
PII:
S0022-328X(18)30855-6
DOI:
https://doi.org/10.1016/j.jorganchem.2018.10.016
JOM 20601
Reference:
To appear in: Journal of Organometallic Chemistry
Received Date: 30 September 2018
Revised Date: 19 October 2018
Accepted Date: 20 October 2018
Please cite this article as: W. Ruan, C. Shi, H.H.Y. Sung, I.D. Williams, G. Jia, Synthesis and reactivity
of platinum vinylcarbene complexes prepared from activation of propargyl alcohols, Journal of
Organometallic Chemistry (2018), doi: https://doi.org/10.1016/j.jorganchem.2018.10.016.
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ACCEPTED MANUSCRIPT
Synthesis and Reactivity of Platinum Vinylcarbene Complexes Prepared
from Activation of Propargyl Alcohols
Wenqing Ruan, Chuan Shi, Herman H. Y. Sung, Ian D. Williams and Guochen
Jia*
Department of Chemistry, The Hong Kong University of Science and Technology,
Clear Water Bay, Kowloon, Hong Kong. Email: chjiag@ust.hk
Dedicated to Professor Richard J. Puddephatt on the Occasion of His 75th
Birthday
1

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Graphical abstract
Cl
OH
Ph
Ph
Cl
Cl
OEt
Cl
PPh3
EtOH
Ph3P
Cl
Pt
Ph3P Pt
Cl
C
Pt
+
Ph
Ph
H
A convenient route to make platinum vinylcarbene complexes is described. Treatment of
[PtCl2(PPh3)]2 with propargyl alcohols HC≡CC(OH)RR’ (RR’ = Ph2, cyclo-C6H10(OH),
(iPr)(C≡CTMS) and (H)(Ph)) in the presence of EtOH produced the vinylcarbene
complexes trans-PtCl2{=C(OEt)-CH=CRR’}(PPh3).
2

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Synthesis and Reactivity of Platinum Vinylcarbene Complexes Prepared
from Activation of Propargyl Alcohols
Wenqing Ruan, Chuan Shi, Herman H. Y. Sung, Ian D. Williams and Guochen
Jia*
Department of Chemistry, The Hong Kong University of Science and Technology,
Clear Water Bay, Kowloon, Hong Kong. Email: chjiag@ust.hk
Dedicated to Professor Richard J. Puddephatt on the Occasion of His 75th
Birthday
1

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Abstract. Platinum vinylcarbene complexes are potentially useful for organometallic
synthesis and catalysis, but have been rarely studied. This work reports a convenient
route to make platinum vinylcarbene complexes. Treatment of [PtCl2(PPh3)]2 with
propargyl alcohols HC≡CC(OH)RR’ (RR’ = Ph2, cyclo-C6H10(OH), (iPr)(C≡CTMS)
and (H)(Ph)) in the presence of EtOH produced the vinylcarbene complexes trans-
PtCl2{=C(OEt)-CH=CRR’}(PPh3). Under similar condition, [PtCl2(PPh3)]2 reacted with
HC ≡ CC(OH)Me2 to give cis-PtCl2{=C(OEt)-CH=CMe2}(PPh3). Complex trans-
PtCl2{=C(OEt)-CH=CPh2}(PPh3) readily undergo a metathesis reaction with NaI to give
trans-PtI2{=C(OEt)-CH=CPh2}(PPh3) which can isomerize to cis-PtI2{=C(OEt)-
CH=CPh2}(PPh3). Complex trans-PtCl2{=C(OEt)-CH=CPh2}(PPh3) reacted with PPh3 to
give EtCl and the acyl complex trans-PtCl{C(O)CH=CPh2}(PPh3)2, which can undergo a
decarbonylation reaction to give PtCl(CH=CPh2)(PPh3)2.
Key words: platinum, carbene, vinylcarbene, alkyne, propargyl alcohol
2

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1. Introduction
Vinylcarbene complexes are an interesting class of organometallic compounds
that can play an important role in catalysis and organic and organometallic synthesis. For
example, RuCl2(=CH-CH=CPh2)(PR3)2 (PR3 = PPh3, PCy3) are catalytically active for
olefin metathesis [1], M{=C(OR)-CH=CR2}(CO)5 (M = Cr, Mo, and W) can be used as
starting materials to synthesize
a
variety of organic compounds [2],
[Cp*Ir{=C(OMe)CH=CPh2}(L)]PF6 (L = PPh2Me, PMe3) can be used to prepare
metallabenzenes [3].
While many transition metal vinylcarbene complexes (especially those of group
6-9 metals) [2,4] and platinum carbene complexes [5-9] are known, well-characterized
platinum vinylcarbene complexes are still rare. Reported platinum vinylcarbene
complexes are mainly those derived from transmetallation reactions of group 6 Fischer
vinylcarbene complexes (e.g. 2 from the reactions of 1 with PtCl2(PhCN)2 [10-11])
(Scheme 1). The transmetallation reactions have been explored for organometallic
synthesis [12] and organic synthesis using group 6 Fischer carbene complexes as starting
materials and group 10 metal complexes as catalysts [4f,13]. There has also been much
interest in developing catalytic reactions involving reactive vinylcarbene intermediates
generated from reactions of other substrates with platinum complexes, for example,
vinylcarbenes 4 from propargyl derivatives 3 [14] and 2-furylcarbenes 6 from ene-yne-
ketones 5 [15]. In view of the rarity of isolated platinum vinylcarbene complexes and
their potential applications in organometallic synthesis and catalysis, it is desirable to
search for alternative routes to make such complexes and to study their reactivity.
3

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Ar
N
Ar
Ph
Ph
N
OEt
PtCl2(PhCN)2
Pt
NHAr
Ph
(OC)5M
OEt
OEt
2
1, M = Cr, W
R
R
R'
R'
O
O
X
[Pt]
[Pt]
O
X
O
R
[Pt]
[Pt]
R
R
6
5
4
3
R
proposed reactive
intermediates
proposed reactive
intermediates
X = O, S
Scheme 1. Vinylcarbene platinum complexes.
We herein report the synthesis and reactivity of platinum vinylcarbene complexes
of the type PtCl2{=C(OR’’)-CH=CRR’}(PPh3) made from the reactions of readily
available propargylic alcohols HC≡CC(OH)RR’ with [PtCl2(PPh3)]2 in the presence of
R”OH.
2. Results and Discussion
2.1. Reactions of [PtCl2(PPh3)]2 with propargyl alcohols HC≡CC(OH)RR’.
Reactions of terminal alkynes HC≡CR with Pt(II) complexes in the presence of
alcohols (ROH) represent one of the most convenient routes to prepare platinum carbene
complexes LnPt=C(OR)CH2R [16-22]. The reactions presumably proceed through the
addition reactions of alcohols with vinylidene intermediates LnPt=C=CHR. We
envisioned that reactions of terminal propargyl alcohols with Pt(II) complexes in the
presence of alcohols may proceed similarly to give hydroxyvinylidene complexes which
4

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could undergo dehydration and addition of alcohols to give desired platinum
vinylcarbene complexes.
To test the hypothesis, we first carried out the reaction of HC≡CC(OH)Ph2 with
the dimeric complex [PtCl2(PPh3)]2 (7) in a mixed solvent of EtOH and CHCl3 (1:6 V/V).
To our delight, the reaction proceeded smoothly to give the vinylcarbene complex trans-
PtCl2{=C(OEt)-CH=CPh2}(PPh3) (8) (Scheme 2). The reaction was completed at room
temperature within 4 h and complex 8 can be isolated as a yellow solid in 90% yield.
Under similar condition, the reaction in a mixture of MeOH and CH2Cl2 (3:10 V/V)
produced the analogous complex trans-PtCl2{=C(OMe)-CH=CPh2}(PPh3) (9).
Cl
OH
Ph
Ph
Cl
Cl
7
OR
Cl
Ph3P
Cl
ROH
Pt
Pt
+
Ph3P Pt
Cl
C
Ph
Ph
PPh3
rt, 4 h
H
8, R = Et; 9, R = Me
- H2O
Ph
HO
Cl
Cl
Ph
OR
Ph3P Pt
Cl
C
OH
Ph
Ph3P Pt
ROH
Cl
Ph
C
A
ROH
Cl
Cl
Ph
H
Ph3P Pt
Cl
C
C
C
Ph3P Pt
C
C
OH
Ph
Ph
C
- H2O
Cl
D
Ph
B
Scheme 2. Preparation of vinylcarbene complexes 8 and 9.
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The structures of complexes 8 and 9 have been confirmed by X-ray diffraction.
The molecular structures of 8 and 9 are shown in Figure 1 and 2, respectively. The two
complexes have very similar structural features. Both adopt a distorted square-planar
geometry with two mutually trans chloride ligands and a carbene ligand trans to PPh3.
The carbene carbon has a planar geometry. The O(1)-C(1)-C(2) plane is almost
perpendicular to the plane formed by Pt, Cl(1), Cl(2) and P(1) atoms. The Pt-C(1) bond
lengths [1.997(3) Å for 8, 1.985(2) Å for 9] are comparable to those found for cationic
alkyl(alkoxy)carbenes such as trans-[Pt(Me){C(OMe)Me}(PMe2Ph)2][PF6] (2.13(1) Å)
[23] and trans-[Pt(Me){COCH2CH2CH2}(PMe2Ph)2][PF6] (2.00(2) Å) [24]. It is however
longer
than
that
reported
for
the
neutral
carbene
complex
cis-
PtC12{C(OEt)(CH2Ph)}(PMe2Ph) (1.920(9) Å) [Error! Bookmark not defined.b], in
which the carbene ligand is trans to a chloride ligand.
6

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Figure 1. The X-ray crystal structure of complex 8 (at 30% probability level of
the thermal ellipsoid). Except the hydrogen on C2, all the hydrogen atoms are omitted for
clarity. Selected bond distances (Å): Pt(1)-C(1) 1.997(3), Pt(1)-P(1) 2.3412(7), Pt(1)-Cl(1)
2.3061(8), Pt(1)-Cl(2) 2.3022(8), C(1)-C(2) 1.448(4), C(2)-C(3) 1.363(4), C(1)-O(1)
1.289(4).
Figure 2. X-ray crystal structure of complex 9 (at 30% probability level of the
thermal ellipsoid). Except the hydrogen on C2, all the hydrogen atoms are omitted for
clarity. Selected bond distances (Å): Pt(1)-C(1) 1.985(2), Pt(1)-P(1) 2.3411(6), Pt(1)-Cl(1)
2.3124(5), Pt(1)-Cl(2) 2.3012(5), C(1)-C(2) 1.460(3), C(2)-C(3) 1.364(3), C(1)-O(1)
1.295(3).
The solid-state structures are supported by their solution NMR data. For example,
the 31P{1H} NMR spectrum of 8 showed a singlet peak at 10.6 ppm flanked by 195Pt
2
13
satellite signals with a JPtP coupling constant of 2090 Hz. The C{1H} NMR spectrum
7

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2
showed the characteristic signal of Pt=C at 271.3 ppm with a JPC coupling constant of
146.7 Hz, the =CH signal at 133.8 ppm and the CPh2 signal at 161.9 ppm. In the 1H NMR
spectrum, the OCH2CH3 signals were observed at 5.54 (CH2) and 1.34 (CH3) ppm.
Scheme 2 shows two plausible paths for the formation of complexes 8 and 9. The
reaction of the dimeric complex 7 with HC≡CC(OH)Ph2 may initially produce the η2-
alkyne complex A, which can isomerize to the vinylidene complex B. The vinylidene
complex B could react with ROH to give the hydroxycarbene complexes C which
undergo dehydration reactions to give complexes 8 and 9. Alternatively, the vinylidene
complex B could undergo a dehydration reaction first to give the allenylidene complex D,
which undergoes addition reactions with ROH to give complexes 8 and 9. Unfortunately,
we have failed to detect the reaction intermediates. As monitored by in situ NMR
spectroscopy, no reaction between 7 and HC≡CC(OH)Ph2 was observed in the absence of
EtOH or MeOH even after overnight. In the presence of EtOH or MeOH, the in situ
NMR spectra only showed signals of the starting dimeric complex 7 and the products.
In the presence of EtOH, the dimeric complex 7 also reacted with the alkyl-
substituted terminal propargyl alcohol 1-ethynylcyclohexanol and the ethynyl-substituted
terminal propargyl alcohol HC≡CC(OH)(iPr)C≡CTMS to give analogous vinylcarbene
complexes 10 and 11, respectively (Scheme 3). Secondary propargyl alcohols behaved
similarly. For example, HC≡CCH(OH)Ph reacted with 7 in the presence of EtOH to give
complex trans-PtCl2(=C(OEt)-CH=CHPh)(PPh3) (12). Interestingly, the dimeric complex
7 reacted with HC≡CC(OH)Me2 in the presence of EtOH to give cis-PtCl2(=C(OEt)-
CH=CMe2)(PPh3) (13) rather than the trans isomer. We noted that complexes cis-
8

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PtX2{=C(OR')(CH2R)}(L) (X = CI, Br, I; L = PMe2Ph or PEt3) were produced from the
reactions of the halide-bridged dimeric complexes [PtX2L]2 with terminal acetylenes RC
≡CH (R = Ph, Me, or Et) and alcohols R'OH (R' = Me, Et, Pr) [16a, b].
Cl
iPr
Cl
HO
OEt
TMS
iPr
Ph3P Pt
Cl
C
OEt
Ph3P Pt
Cl
C
OH
H
rt, 10 h
rt, 10 h
H
TMS
11
10
Cl
Cl
Ph3P
Cl
+
EtOH
Pt
Pt
Cl
PPh3
7
Cl
PPh3
OEt
OH
Me
Me
OH
H
Ph
OEt
Ph3P Pt
Cl
C
H
Cl Pt
Cl
C
Me
Me
H
Ph
H
rt, 24 h
rt, 10 h
12
13
Scheme 3. Preparation of vinylcarbene complexes 10-13.
The coordination sphere of complexes 10-12 must be the same as those of
31
complexes 8-9, as indicated by their NMR data. In particular, the P{1H} NMR spectra
1
of these complexes showed a singlet at ca. 11 ppm with a JPtP coupling constant of ca.
2150 Hz. The 13C{1H} NMR spectra showed a carbene signal at ca. 270 ppm with a 2JPC
coupling constant of ca. 150 Hz.
The NMR data of 13 is significantly different from those of 8-12. The 31P{1H}
NMR spectrum showed a singlet peak at 8.0 ppm with a 2JPtP coupling constant of 4105.0
Hz, which is significantly larger than those of 8-12 (ca. 2150 Hz). The 13C{1H} NMR
9

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2
spectrum showed the Pt=C signal at 247.6 ppm with a JPC coupling constant of 4.2 Hz,
1
which is significantly smaller than those of 8-12 (ca. 150 Hz). In the H NMR spectrum,
the OCH2 group displayed two signals at 5.60 and 4.94 ppm, indicating that complex has
an unsymmetrical structure. The NMR data suggest that the phosphine and carbene
ligands in 13 are cis to each other.
The structure of 13 has been confirmed by an X-ray diffraction study. As shown
in Figure 3, complex adopts a square-planar geometry around Pt with two mutually cis
chloride ligands. As expected, the Pt-P bond (2.2431(19) Å) and Pt-C(carbene) (1.926(10)
Å) distances are appreciably shorter than the corresponding bonds in complexes 8 and 9.
The difference is understandable as the phosphine and carbene ligands are mutually trans
to each other in 8 and 9, but are trans to a chloride ligand in 13. Chloride is a weaker
trans influence ligand than phosphine and carbene ligands.
10

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Figure 3. X-ray crystal structure of complex 13 (at 30% probability level of the
thermal ellipsoid). Except the hydrogen on C2, all the hydrogen atoms are omitted for
clarity. Selected bond distances (Å): Pt(1)-C(1) 1.926(10), Pt(1)-P(1) 2.2431(19), Pt(1)-
Cl(1) 2.367(2), Pt(1)-Cl(2) 2.359(2), C(1)-C(2) 1.433(13), C(2)-C(3) 1.333(14), C(1)-O(1)
1.295(16).
It is interesting to note that the vinylcarbene complex obtained from the reaction
of HC≡CC(OH)Me2 adopts a cis geometry while those from other tested propargyl
alcohols adopt a trans geometry. Our computational work confirms that the cis isomer is
thermodynamically slightly more stable than the trans isomer for both PtCl2{=C(OEt)-
CH=CPh2}(PPh3) and PtCl2{=C(OEt)-CH=CMe2}(PPh3) as shown in Figure 4. Thus,
complexes 8-13 are the kinetic products, although it is not clear to us the cause for the
difference in the kinetic preferences. We have tried to convert complex trans-
PtCl2(=C(OEt)-CH=CPh2)(PPh3) (8) to its cis isomer by heating. It was found that
complex decomposed to a mixture of several un-identified species along with complex 7
after refluxing in THF or chloroform overnight.
11

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Figure 4. The relative stability of isomers of PtCl2{=C(OEt)-CH=CPh2}(PPh3)
and PtCl2{=C(OEt)-CH=CMe2}Cl2(PPh3). The relative free energies and electronic
energies (in parentheses) are given in kcal/mol.
We also carried out the reactions of 7 with HC≡CC(OH)Ph2 in the presence of
i
tBuOH, PhCH2OH, HOAc and Pr2NH. As indicated by in situ 31P(1H) NMR
spectroscopy, the reactions of tBuOH and PhCH2OH also produced analogous
vinylcarbene complexes. However, the reactions are not clean and also produced other
unidentified complexes. We have failed to obtain pure samples of these vinylcarbene
complexes. In the case of HOAc, no reaction was observed even after 24 h. In the case of
iPr2NH, the expected vinylcarbene complex was not observed. Instead, the reaction
produced the amine complex trans-PtCl2(PPh3)(iPr2NH) [25].
2.2. Reactivity of trans-PtCl2(=C(OEt)-CH=CPh2)(PPh3) (8).
One of the interesting transformations of haloplatinum alkoxycarbene complexes
of the type [Pt]X{=C(OR)R’} is the elimination of RX to give platinum acyl complexes
12

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[Pt][=C(O)R’]. The reactions can be promoted by halides or neutral ligands such as
phosphines and pyridine. For example, trans-[PtCl(=C(OMe)Me)(PMe2Ph)2]PF6 reacted
NaI to give trans-PtX(COMe)(PMe2Ph)2 (X = Cl, I) [26], cis-PtBr2{C(OMe)(Me)}2
reacted with PPh3 to give trans-PtBr(COMe){C(OMe)(Me)}(PPh3) and MeBr [27], cis-
PtCl2{C(OMe)(Et)}(PMe2Ph) reacted with PMe2Ph to give trans-PtCl(COEt)(PMe2Ph)2
and
MeCl
[Error!
Bookmark
not
defined.c].
Complexes
cis-
PtCl2{=C(OMe)(R)}(PMe2Ph) (R = Et, CH2Ph) were also reported to slowly evolve to
the acyl complex [PtCl(COR)(PMe2Ph)]2 in CHCl3 and the reaction is facilitate by
addition of Et4NCl [Error! Bookmark not defined.c].
We have carried out experiments to see if our vinylcarbene complex trans-
PtCl2(=C(OEt)-CH=CPh2)(PPh3) (8) behaves similarly. Complex PtCl2(=C(OEt)-
CH=CPh2)(PPh3) (8) was found to remain unchanged in dichloromethane, chloroform or
THF even after 20 h. It decomposed completely to a mixture of un-identified species after
its THF solution was allowed to stand at room temperature for 7 h in the presence of four
equiv. of LiCl or Bu4NCl.
Interestingly complex 8 in THF reacted rapidly with NaI to give the diiodo-
vinylcarbene complex trans-PtI2{=C(OEt)-CH=CPh2}(PPh3) (14A) (Scheme 4), which
can be isolated as a yellow solid in 95% yield from the reaction of 8 with 10 equiv. of
NaI at room temperature for 5 min. If the reaction was carried out in refluxing THF for
2.5 h, the reaction produced complex 14A along with the isomeric complex cis-
PtI2(=C(OEt)-CH=CPh2)(PPh3) (14B) in a molar ratio of 1 : 0.23. Complex 14B is the
only product if the reaction mixture was refluxed for two days. Complex 14B is
13

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presumably formed from isomerization of complex 14A. Indeed, upon heating in THF for
two days, isolated isomer 14A was converted completely to the isomer 14B.
Cl
I
OEt
OEt
THF
Ph3P Pt
Cl
C
+
NaI
Ph3P Pt
C
Ph
Ph
Ph
Ph
rt, 5 min
I
H
H
14A
8
THF
90 oC, 2 d
PPh3
OEt
I
Pt
I
C
Ph
Ph
H
14B
Scheme 4. The reaction of the vinylcarbene complex 8 with NaI.
The compositions of the two isomers of complex 14 have been confirmed by their
analytical and NMR spectroscopic data. The stereochemistry of the two isomers can be
assigned based on the NMR data. In complex 14A, the phosphine ligand is trans to the
carbene ligand. In complex 14B, the phosphine ligand is trans to an iodide ligand and cis
1
to the carbene ligand. In agreement with the stereochemistry, the JPtP coupling constant
1
of 14A (2118.8 Hz) is smaller than that of 14B (3924.2 Hz). In addition, the H NMR
spectrum of 14A showed only one CH2 signal at 5.04 ppm due to the symmetrical feature
of the structure while that of 14B showed two CH2 signals at 4.97 and 4.35 ppm due to
the unsymmetrical feature of the structure.
14

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Complex 8 in THF reacted with PPh3 immediately at room temperature to
produce the acyl complex trans-PtCl{C(O)CH=CPh2}(PPh3)2 (15) along with EtCl,
which was identified by NMR spectroscopy (Scheme 5). Complex 15 can be isolated as a
yellow solid in 90% yield from the reaction of 8 with ca. 4 equiv. of PPh3 in THF for 15
min.
If the reaction was carried out in refluxing THF for 20 min, the reaction produced
the acyl complex 15 along with the vinyl complex PtCl2(CH=CPh2)(PPh3) ( as a mixture
of the cis isomer 16A and the trans isomer 16B in a molar ratio of 1 : 3) in a molar ratio
of 1 : 14. Complex 16 is presumably formed from decarbonylation of 15. Subsequent
experiments confirmed that the isolated acyl complex 15 can indeed undergo a
decarbonylation reaction in both solid state and solutions. In refluxing dichloromethane,
the decarbonylation reaction was completed within 20 h to give a mixture of the cis- and
trans isomers of the vinyl complex 16 (16A and 16B are in a molar ratio of 1:7).
Refluxing a solution of 15 in chloroform for one h produced cleanly only the trans
isomer 16B. The observations may suggest that the decarbonylation reaction initially
produced isomer 16A, which can isomerize to the thermodynamically more stable isomer
16B. In agreement of the proposition, isolated isomer 16A could be converted to isomer
16B on refluxing in chloroform for 4 h. Similar decarbonylation reactions have been
reported for trans-Pt(COMe)Cl(PR3)2 (PR3 = PPh3, P(4-FC6H4)3, PMePh2, PMe2Ph and
PBu3) [28].
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Cl
PPh3
Cl Pt
PPh3
OEt
O
THF, r.t., 5 min.
EtCl
Ph3P Pt
C
+
PPh3
C
Ph
Ph
Ph
Ph
Cl
15
H
H
8
CHCl3
CH2Cl2
reflux,1 h
reflux, 20 h
Ph
Ph
Cl
Ph3P Pt
PPh3
Ph
H
PPh3
Cl Pt
PPh3
CHCl3
Ph
H
reflux, 1 h
16A
16B
Scheme 5. Reactions of the vinylcarbene complex 8 with PPh3.
The identity of the acyl complex 15 is supported by the NMR data. In particular,
2
the 31P{1H} NMR spectrum showed a singlet peak at 19.8 ppm with a JPtP coupling
constant of 3532.1 Hz, suggesting that the two phosphine ligands are equivalent and must
be trans to each other. The 13C{1H} NMR spectrum showed the characteristic signal of
PtC(O) signal at 205.7 ppm with a small 2JPC coupling constant of 5.3 Hz, the =CH signal
at 136.3 ppm and the CPh2 signal at 143.4 ppm. In the 1H NMR spectrum, the vinyl =CH
signal was observed at 6.68 ppm.
The two isomers of Complex 16 have been characterized by elemental analysis
and NMR spectroscopy The structure of 16B has also been confirmed by X-ray
diffraction. As shown Figure 5, complex 16B adopts a square planar geometry with two
trans-disposed PPh3 ligands. Consistent with the solid state structure, the 31P{1H} NMR
2
spectrum of 16B showed a singlet peak at 24.4 ppm with a JPtP coupling constant of
16

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13
3122.5 Hz. The C{1H} NMR spectrum showed a triplet signal of Pt-CH at 136.1 ppm
with a 2JPC coupling constant of 9.6 Hz, and the =CPh2 signal at 139.5 ppm.
Consistent with the cis-geometry, complex 16A showed two 31P{1H} signals at
21.1 and 16.2 ppm. The 13C{1H} NMR spectrum showed a triplet signal of Pt-CH at
2
149.7 ppm with a JPC coupling constant of 114.1 Hz, which is typical for coupling
between trans-disposed phosphine and vinyl ligands.
Figure 5. The X-ray crystal structure of complex 16B (at 30% probability level
of the thermal ellipsoid). Except the hydrogen on C1, all the hydrogen atoms are omitted
for clarity. Selected bond distances (Å): Pt(1)-C(1), Pt(1)-P(1), Pt(1)-P(2), Pt(1)-Cl(1),
Pt(1)-C)1), C(1)-C(2).
17

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Carbene complexes can be oxidized to give carbonyl derivatives [29]. We found
that complex 8 can undergo similar reactions. For example, it reacted with PhIO or
Me3NO in CHCl3 to give the ester Ph2C=CHCO2Et (17) (eq. 1). As indicated by in situ
NMR spectroscopy, the reaction also produced phosphine oxide Ph3P=O and other
unidentified products. We have carried out experiments to test whether the dimeric
complex [PtCl2(PPh3)]2 can catalyze the reaction of HC≡CC(OH)Ph2 with PhIO and
EtOH to give the ester 17. Experimentally, 17 was indeed formed after a mixture of HC
≡CC(OH)Ph2, PhIO (or Me3NO) and EtOH (in 1:1:1 molar ratio) was refluxed in CHCl3
overnight in the presence of 10 mol% of [PtCl2(PPh3)]2. Unfortunately, only a
conversion of 10% was achieved.
OEt
Cl
CHCl3
- PhI
OEt
O
Ph
Ph
(1)
Ph3P Pt
Cl
C
+ O=PPh3
+ PhIO
Ph
Ph
H
H
17
8
In summary, platinum vinylcarbene complexes PtCl2(=C(OR”)-CH=CRR’)(PPh3)
can be conveniently prepared from the reactions of [PtCl2(PPh3)]2 with propargyl alcohols
HC≡CC(OH)RR’ in the presence of alcohols R”OH. Complex trans-PtCl2(=C(OEt)-
CH=CPh2)(PPh3) readily undergo a metathesis reaction with NaI to give trans-
PtI2(=C(OEt)-CH=CPh2)(PPh3),
which can
isomerize to
cis-PtI2(=C(OEt)-
CH=CPh2)(PPh3). Complex trans-PtCl2(=C(OEt)-CH=CPh2)(PPh3) reacted with PPh3 to
18

ACCEPTED MANUSCRIPT
give EtCl and the acyl complex trans-PtCl{C(O)CH=CPh2}(PPh3)2, which can undergo
a decarbonylation reaction to give PtCl(CH=CPh2)(PPh3)2.
3. Experimental section.
General Procedures. All reactions were carried out in oven-dried glassware
under an atmosphere of argon with the rigid exclusion of air and moisture using standard
Schlenk techniques or in a glovebox under N2 unless otherwise specified. Diethyl ether,
n-hexane, n-pentane and tetrahydrofuran were distilled from sodium benzophenone ketyl,
toluene was distilled from sodium, and dichloromethane was distilled from calcium
hydride. [PtCl2(PPh3)]2 (7) was prepared according to a reported procedure [30]. All other
chemicals were purchased from either Aldrich or Acros Chemical Co. and used as
1
received unless otherwise specified. H, 13C{1H}, and 31P{1H} NMR spectra were
recorded on a Bruker DPX 400 spectrometer at 400 MHz, 100 MHz and 162 MHz,
respectively. All signals are reported in δ unit with references to the residual solvent
resonances of the deuterated solvents for proton and carbon chemical shifts, and to
external 85% H3PO4 for phosphorus chemical shifts. Microanalyses were performed in
M-H-W Laboratories (Phoenix, AZ, USA).
Synthesis of 8. To a solution of [PtCl2(PPh3)]2 (7) (1.00 g, 0.946 mmol) in CHCl3
(60 mL) was added 1,1-diphenylprop-2-yn-1-ol (788 mg, 3.78 mmol) and ethanol (10
mL). The reaction mixture was stirred for 4 h at room temperature to give a clear yellow
solution. All volatiles of the reaction mixture were removed under vacuum. The residue
19

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was washed with n-hexane (15 mL × 2), ether (10 mL) and dried under reduced pressure
1
to provide complex 8 as a yellow solid. Yield, 90% (1.31 g, 1.71 mmol). H NMR (400
MHz, CDCl3): δ 7.59 - 7.32 (m, 26H), 5.54 (q, J = 7.1 Hz, 2H, CH2), 1.34 (t, J = 7.1 Hz,
3H, CH3). 31P{1H} NMR (162 MHz, CDCl3): δ 10.6 (s, JPtP = 2090.0 Hz). 13C{1H} NMR
(100 MHz, CDCl3): δ 271.3 (d, JPC = 146.7 Hz, Pt=C), 161.9 (HC=CPh2), 140.9 (ipso-
CPh2), 139.0 (ipso-CPh2), 134.8 (d, J = 10.9 Hz, o- or m-PPh3), 133.8 (d, JPC = 9.9 Hz,
HC=CPh2), 131.2, 131.0, 130.3 (br, p-PPh3), 129.8, 129.4 (d, JPC = 48.2 Hz, ipso-PPh3),
129.1, 128.5, 128.0 (d, J = 10.0 Hz, o- or m-PPh3), 127.9, 78.9 (d, JPC = 3.6 Hz, CH2),
14.0 (CH3). Anal. Calcd. for C35H31Cl2OPPt: C, 54.98, H, 4.09. Found: C, 54.67, H, 4.08.
Synthesis of 9. To a solution of [PtCl2(PPh3)]2 (200 mg, 0.189 mmol) in CH2Cl2
(10 mL) was added 1,1-diphenylprop-2-yn-1-ol (198 mg, 0.951 mmol) and ethanol (3
mL). The reaction mixture was stirred for 4 h at room temperature to give a clear yellow
solution. All volatiles of the reaction mixture were removed under vacuum. The residue
was washed with n-hexane (5 mL × 2), ether (3 mL) and dried under reduced pressure to
1
provide complex 9 as a yellow solid. Yield, 75% (214 mg, 0.284 mmol). H NMR (400
MHz, CDCl3): δ 7.56 - 7.29 (m, 26H), , 4.99 (s, 3H, CH3). 31P{1H} NMR (162 MHz,
CDCl3): δ 9.9 (s, J = 2114.4 Hz). 13C{1H} NMR (100 MHz, CDCl3): δ 271.7 (d, J =
146.2 Hz, Pt=C), 165.3 (HC=CPh2), 140.6 (ipso-CPh2), 138.3 (ipso-CPh2), 134.1 (d, J =
10.2 Hz, o- or m-PPh3), 133.6 (d, J = 10.6 Hz, HC=CPh2), 131.3, 130.6, 129.6 (br, p-
PPh3), 129.3,129.0, 128.7 (d, J = 49.1 Hz, ipso-PPh3), 127.8, 127.3 (d, J = 10.6 Hz, o- or
20

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m-PPh3), 127.2, 67.5 (d, J = 2.8 Hz, OCH3). Anal. Calcd. for C34H29Cl2OPPt: C, 54.41, H,
3.89. Found: C, 54.61, H, 3.93.
Synthesis of 10. To a solution of [PtCl2(PPh3)]2 (300 mg, 0.283 mmol) in CHCl3 (25
mL) was added 1-ethynylcyclohexan-1-ol (720 mg, 5.80 mmol) and ethanol (4 mL). The
reaction mixture was stirred for 10 h at room temperature to give a clear yellow solution.
All volatiles of the reaction mixture were removed under vacuum. The residue was
washed with cold pentane (5 mL × 2), then purified by column chromatography on SiO2
using dichloromethane as the eluent. The yellow band was collected, then recrystallized
from Et2O to provide complex 10 as a yellow solid. Yield, 35% (138 mg, 0.198 mmol).
1H NMR (400 MHz, CD2Cl2): δ 7.67 - 7.72 (m, 6H), 7.45 - 7.53 (m, 9H), 6.53 (d, J = 8.1
Hz, 1H, CH=Cy), 5.83 (q, J = 7.1 Hz, 2H, OCH2), 4.44 (t, J = 6.0 Hz, 2H, CH2), 2.48 (t, J
= 5.8 Hz, 2H, CH2), 1.94 - 1.97 (m, 2H, CH2), 1.83 - 1.86 (m, 2H, CH2), 1.70 – 1.76 (m,
31
5H, CH2, OCH2CH3). P{1H} NMR (162 MHz, CD2Cl2): δ 12.3 (s, JPtP = 2136.3 Hz).
13C{1H} NMR (100 MHz, CD2Cl2): δ 268.8 (d, J = 145.9 Hz, Pt=C), 183.1 (HC=CR2),
134.0 (d, J = 10.1 Hz, o- or m-PPh3),132.1 (d, J = 11.2 Hz, HC=Cy), 129.7 (d, J = 2.1 Hz,
p-PPh3), 128.9 (d, J = 49.5 Hz, ipso-PPh3), 127.4 (d, J = 10.4 Hz, o- or m-PPh3), 78.6 (d,
J = 2.6 Hz, OCH2), 39.6 (CH2), 35.1 (CH2), 28.9 (CH2), 28.0 (CH2), 25.3 (CH2),13.8
(CH3). Anal. Calcd. for C28H31Cl2OPPt: C, 49.42, H, 4.59. Found: C, 49.74, H, 4.49
Synthesis of 11. To a solution of [PtCl2(PPh3)]2 (200 mg, 0.189 mmol) in CHCl3 (15
mL) was added 3-isopropyl-1-(trimethylsilyl)penta-1,4-diyn-3-ol (150 mg, 0.772 mmol)
and ethanol (4 mL). The reaction mixture was stirred for 10 h at room temperature to give
21

ACCEPTED MANUSCRIPT
a clear yellow solution. All volatiles of the reaction mixture were removed under vacuum.
The residue was washed with cold n-pentane (2 mL × 2) and dried under vacuum, then
purified by column chromatography on SiO2 using mixtures of ethyl acetate : n-hexane (=
1 : 30), and then methanol : dichloromethane (= 1 : 100) as the eluents. A yellow-green
band was collected. The solvents were removed under reduced pressure to provide
1
complex 11 as a yellow solid. Yield, 30% (85.5 mg, 0.113 mmol). H NMR (400 MHz,
CDCl3): δ 7.62 - 7.67 (m, 6H), 7.38 - 7.46 (m, 9H), 6.70 (d, J = 7.6 Hz, 1H, CH=CR2),
6.57 (sept, J = 6.6 Hz, 1H, CHMe2), 5.80 (q, J = 7.1 Hz, 1H, OCH2), 1.68 (t, J = 7.2 Hz,
3H, OCH2CH3), 1.26 (d, J = 6.6 Hz, 6H, CHMe2), 0.23 (s, 9H, SiMe3). 31P{1H} NMR
(162 MHz, CDCl3): δ 11.8 (s, J = 2145.0 Hz). 13C{1H} NMR (100 MHz, CDCl3): δ 269.3
(d, J = 147.2 Hz, Pt=C), 161.4 (HC=CR2), 139.4 (d, J = 11.4 Hz, HC=CR2), 134.0 (d, J =
10.7 Hz, o- or m-PPh3), 129.7 (p-PPh3), 128.7 (d, J = 50.0 Hz, ipso-PPh3), 127.4 (d, J =
10.0 Hz, o- or m-PPh3), 110.9 (C≡CTMS), 103.4 (C≡CTMS), 79.2 (d, J = 3.2 Hz, OCH2),
32.8 (CHMe2), 20.7 (CHMe2),13.9 (OCH2CH3), -1.08 (SiMe3). Anal. Calcd. for
C31H37Cl2OPPtSi: C, 49.60, H, 4.97. Found: C, 49.72, H, 4.82.
Synthesis of 12. To a solution of [PtCl2(PPh3)]2 (150 mg, 0.142 mmol) in CHCl3 (15
mL) was added 1-phenylprop-2-yn-1-ol (370 mg, 2.80 mmol) and ethanol (3 mL). The
reaction mixture was stirred for 24 h at room temperature to give a clear yellow solution.
All volatiles of the reaction mixture were removed under vacuum. The residue was
washed with n-hexane (15 mL × 2), then purified by column chromatography on SiO2
using dichloromethane as the eluent, the yellow band was collected, and the solvents
22

ACCEPTED MANUSCRIPT
were removed under reduced pressure to provide complex 12 as a green solid. Yield, 30%
1
(57.8 mg, 0.084 mmol). H NMR (400 MHz, CD2Cl2): δ 9.27 (d, JH-H = 15.6 Hz, 1H,
CH=CHPh ), 7.80 - 7.82 (m, 2H), 7.70 - 7.75 (m, 6H), 7.60 - 7.62 (m, 1H), 7.45 - 7.58 (m,
11H), 7.26 (dd, JH-H = 15.6 Hz, JP-H = 7.7 Hz, 1H, -CH=CHPh ), 5.80 (q, J = 7.2 Hz, 2H,
CH2), 1.74 (t, J = 7.1 Hz, 3H, CH3). 31P{1H} NMR (162 MHz, CD2Cl2): δ 12.5 (s, JPtP
=
13
2122.7 Hz). C{1H} NMR (100 MHz, CD2Cl2): δ 271.0 (d, J = 148.6 Hz, Pt=C), 166.5
(HC=CHPh), 134.2 (d, J = 10.2 Hz, o- or m-PPh3), 133.8 (ipso-Ph), 133.7 (d, J = 10.5 Hz,
-HC=CPh2), 132.3 (p-Ph), 129.8 (s, p-PPh3), 129.3, 128.8 (d, J = 49.5 Hz, ipso-PPh3),
128.6, 127.4 (d, J = 10.2 Hz, o- or m-PPh3), 78.3 (d, J = 2.7 Hz, CH2), 13.7 (CH3). Anal.
Calcd. for C35H31Cl2OPPt: C, 54.98, H, 4.09. Found: C, 50.81, H, 4.02.
Synthesis of 13. To a solution of [PtCl2(PPh3)]2 (300 mg, 0.283 mmol) in CHCl3
(25 mL) was added 2-methylbut-3-yn-2-ol (487 mg, 5.80 mmol) and ethanol (4 mL). The
reaction mixture was stirred for 10 h at room temperature to give a clear yellow solution.
All volatiles of the reaction mixture were removed under vacuum. The residue was
washed with n-hexane (10 mL × 2), then recrystallized from DCM / n-hexane to provide
complex 13 as a yellow solid. Yield, 50% (185 mg, 0.283 mmol). 1H NMR (400 MHz,
CD2Cl2): δ 7.66 - 7.71 (m, 6H), 7.51 - 7.54 (m, 3H), 7.42 - 7.47 (m, 6H), 6.37 (s, 1H,
CH=CMe2), 5.60 (m, 1H, OCH2), 4.92 (m, 1H, OCH2), 2.31 (s, 3H, CH3), 1.70 (s, 3H,
CH3), 1.34 (t, J = 7.1 Hz, 3H, OCH2CH3). 31P{1H} NMR (162 MHz, CD2Cl2): δ 8.0 (s, J
PtP = 4105.0 Hz). 13C{1H} NMR (100 MHz, CD2Cl2): δ 247.6 (d, J = 4.2 Hz, Pt=C), 167.9
(HC=CPh2), 134.6 (HC=CPh2), 133.5 (d, J = 10.4 Hz, o- or m-PPh3), 130.9 (d, J = 2.3 Hz,
23

ACCEPTED MANUSCRIPT
p-PPh3), 128.3 (d, J = 64.1 Hz, ipso-PPh3), 127.8 (d, J = 11.3 Hz, o- or m-PPh3), 79.4
(CH2), 28.7 (CH3), 23.7 (CH3),13.2 (CH3). Anal. Calcd. for C25H27Cl2OPPt: C, 46.89, H,
4.25. Found: C, 46.91, H, 4.21.
Synthesis of 14A. A mixture of the platinum vinylcarbene 8 (200 mg, 0.261 mmol)
and NaI (391 mg, 2.61 mmol) in THF (15 mL) was stirred for 5 mins at room
temperature. All volatiles of the reaction mixture were removed under vacuum. The
residue was extracted with DCM (5 mL × 2) and dried under reduced pressure to provide
complex 14A as a yellow solid. Yield: 95% (235 mg, 0.247 mmol). 1H NMR (400 MHz,
CD2Cl2): δ 7.84 (d, J = 1.8 Hz, 1H, CH=CPh2) 7.63 - 7.68 (m, 6H), 7.38 - 7.49 (m, 19H),
31
5.04 (q, J = 7.1 Hz, 2H, CH2), 1.09 (t, J = 7.1 Hz, 3H, CH3). P{1H} NMR (162 MHz,
13
CD2Cl2): δ 8.6 (s, JPtP = 2118.8 Hz). C{1H} NMR (100 MHz, CD2Cl2): δ 269.9 (d, J =
141.3 Hz, Pt=C), 154.9 (d, J = 2.5 Hz, HC=CPh2), 139.6 (ipso-CPh2), 138.3 (ipso-CPh2),
134.6 (d, J = 10.8 Hz, o- or m-PPh3), 133.5 (d, J = 8.0 Hz, HC=CPh2), 130.9 (d, J = 50.0
Hz, ipso-PPh3), 130.3, 129.6 (d, J = 1.9 Hz, p-PPh3), 129.2, 129.0, 128.0, 127.8, 127.2,
127.0 (d, J = 9.8 Hz, o- or m-PPh3), 79.2 (d, J = 3.5 Hz, CH2), 12.1 (CH3). Anal. Calcd.
for C35H31I2OPPt: C, 44.37, H, 3.30. Found: C, 44.44, H, 3.49.
Synthesis of 14B. A solution of 14A (200 mg, 0.211 mmol) in THF (15 mL) was
o
stirred for 2 days at 90 C, all volatiles of the reaction mixture were removed under
vacuum to provide complex 14B as a yellow solid. Yield, 95% (190 mg, 0.200 mmol). 1H
NMR (400 MHz, CD2Cl2): δ 7.71 - 7.77 (m, 6H), 7.51 - 7.54 (m, 3H), 7.42 - 7.48 (m, 8H),
24

ACCEPTED MANUSCRIPT
7.30 - 7.39 (m, 5H), 7.06 - 7.10 (m, 4H), 4.93 - 5.01 (m, 1H, CH2), 4.31 - 4.39 (m, 1H,
31
CH2), 0.73 (t, J = 7.1 Hz, 3H, CH3). P{1H} NMR (162 MHz, CD2Cl2): δ 7.7 (s, J
=
PtP
3924.2 Hz). 13C{1H} NMR (100 MHz, CD2Cl2): δ 249.1 (s, Pt=C), 155.5 (HC=CPh2),
139.2 (ipso-CPh2), 138.2 (ipso-CPh2), 132.8 (d, J = 10.9 Hz, o- or m-PPh3), 131.3,
130.8(p-PPh3), 130.7, 129.6(d, J = 62.3 Hz, ipso-PPh3), 128.8, 128.0, 127.9, 127.7 (d, J =
10.0 Hz, o- or m-PPh3), 127.6, 127.1, 78.7 (CH2), 11.4 (CH3). Anal. Calcd. for
C35H31I2OPPt: C, 44.37, H, 3.30. Found: C, 44.19, H, 3.52.
Synthesis of 15. A mixture of the platinum vinylcarbene 8 (300 mg, 0.392 mmol)
and PPh3 (411 mg, 1.56 mmol) in DCM (20 mL) was stirred for 15 mins at room
temperature. All volatiles of the reaction mixture were then removed under vacuum. The
residue was washed with ether (10 mL × 3) and dried under reduced pressure to provide
1
complex 15 as a yellow solid. Yield, 90% (339 mg, 0.352 mmol). H NMR (400 MHz,
CDCl3): δ 7.76 - 7.79 (m, 12H), 7.33 - 7.40 (m, 18H), 7.24 - 7.26 (m, 1H), 7.14 - 7.18 (m,
3H), 6.99 - 7.03 (m, 2H), 6.72 - 6.74 (m, 2H), 6.68 (s, 1H, CH=CPh2), 6.22 - 6.24 (m,
2H). 31P{1H} NMR (162 MHz, CDCl3) δ 19.8 (t, J = 3532.1 Hz). 13C{1H} NMR (100
MHz, CDCl3): δ 205.7 (t, J = 5.3 Hz, Pt-CO), 143.4 (HC=CPh2), 142.4 (ipso-CPh2),
138.3 (ipso-CPh2), 136.3 (t, J = 6.4 Hz, HC=CPh2), 134.3 (t, J = 6.4 Hz, o- or m-PPh3),
129.8 (t, J = 27.8 Hz, ipso-PPh3), 129.7 (p-PPh3), 129.3, 127.6, 127.4 (t, J = 5.3 Hz, o- or
m-PPh3), 127.2, 127.2, 126.7, 125.8.
25

ACCEPTED MANUSCRIPT
Decarbonylation of 15. Condition A. A solution of 15 (100 mg, 0.104 mmol) in
DCM (15 mL) was refluxed for 20 hours. All volatiles of the reaction mixture were then
removed under vacuum. The residue was extracted with Et2O (5 mL × 3) to leave a
colorless residue. The solvent of the extract was removed under reduced pressure and
dried under reduced pressure to provide complex 16A as a pale yellow solid. Yield, 10%
(9.7 mg, 0.010 mmol). The colorless residue was dried under reduced pressure to provide
complex 16B. Yield, 70% (68.0 mg, 0.073 mmol).
Condition B. A solution of 15 (50.0 mg, 0.052 mmol) in CHCl3 (1 mL) was
refluxed for one hour. All volatiles of the reaction mixture were removed under vacuum.
The residue was dried under reduced pressure to provide complex 16B as a pale yellow
solid. Yield, 99% (48.1 mg, 0.051 mmol). Complex 16B could also be obtained from 16A
as follows. A solution of 16A (20.0 mg, 0.021 mmol) in CHCl3 (0.4 mL) was refluxed for
one hour. All volatiles of the reaction mixture were removed under vacuum to provide
complex 16B as pale yellow solid. Yield, 99% (19.8 mg, 0.021 mmol). Characterization
data of 16A: 1H NMR (400 MHz, CD2Cl2): δ 7.56 – 6.98 (m, 39H), 6.66 - 6.68 (m, 2H).
31P{1H} NMR (162 MHz, CD2Cl2): δ 21.1 (d, JPP = 15.5 Hz, JPtP = 1641.8 Hz), 16.2 (d,
JPP = 14.6 Hz, JPtP = 4450.0 Hz). 13C{1H} NMR (100 MHz, CD2Cl2): δ 149.7 (dd, JPC
=
114.1 Hz, 9.9 Hz, HC=CPh2), 146.5 (d, J = 4.1 Hz, ipso-CPh2), 145.4 (d, J = 11.0 Hz,
HC=CPh2), 140.4 (ipso-CPh2), 134.2 (d, J = 10.3 Hz, o- or m-PPh3), 133.5 (d, J = 11.3
Hz, o- or m-PPh3), 131.0 (d, J = 44.4 Hz, ipso-PPh3), 130.9, 130.0 (d, J = 62.0 Hz, ipso-
PPh3), 129.5 (d, J = 2.0 Hz, p-PPh3), 129.0 (p-PPh3), 127.1 (d, J = 11.0 Hz, o- or m-PPh3),
127.0 (d, J = 9.5 Hz, o- or m-PPh3), 126.4, 126.3, 126.2, 125.1, 124.2. Anal. Calcd. for
26

ACCEPTED MANUSCRIPT
C50H41ClP2Pt: C, 64.27, H, 4.42. Found: C, 63.95, H, 4.63. Characterization data of 16B:
1H NMR (400 MHz, CD2Cl2): δ 7.48 - 7.54 (m, 12H), 7.36 - 7.39 (m, 6H), 7.28 - 7.33 (m,
12H), 7.22 – 7.24 (m, 1H), 7.09 – 7.11 (m, 4H), 6.95 – 6.99 (m, 3H), 6.78 – 6.80 (m, 1H),
6.50 – 6.52 (m, 2H). 31P{1H} NMR (162 MHz, CD2Cl2): δ 24.4 (s, JPtP = 3122.5 Hz).
13C{1H} NMR (100 MHz, CD2Cl2): δ 145.9 (ipso-CPh2), 145.1 (ipso-CPh2), 139.5 (t, J =
3.9 Hz, HC=CPh2), 136.1 (t, J = 9.6 Hz, HC=CPh2), 134.3 (t, J = 6.0 Hz, o- or m-PPh3),
129.6 (p-PPh3), 129.5 (t, J = 27.9 Hz, ipso-PPh3), 129.0, 127.1 (t, J = 5.3 Hz, o- or m-
PPh3), 126.2, 126.1, 126.0, 125.0, 123.8. Anal. Calcd. for C50H41ClP2Pt: C, 64.27, H,
4.42. Found: C, 64.22, H, 4.31.
Crystallographic analysis. Single crystals of 8, 9, 13, 16B suitable for X-ray
diffraction were grown from toluene solutions layered with hexane. Intensity data were
collected on a Rigaku-Oxford Diffraction SuperNova diffractometer at 100 K. Diffraction
data were processed using the CrysAlisPro software (version 1.171.35.19). Empirical
absorption corrections were performed using spherical harmonics, implemented in
SCALE3 ABSPACK scaling algorithm in the CrysAlisPro software suite. Structure
solution and refinement for all compounds were performed using the Olex2 software
package (which embedded SHELXL) [31-32]. All the structures were solved by direct
methods, expanded by difference Fourier syntheses and refined by full matrix least-
squares on F2. All non-hydrogen atoms were refined anisotropically with a riding model
for the hydrogen atoms except noted separately. Further crystallographic details are
summarized in Table S1-S12. Crystallographic data have been deposited with the
27