Platinum allenylidene complexes and formation of platinum and palladium acetonitrile alkynyl complexes

Article abstract of DOI:10.1016/j.ica.2011.02.074

The platinum(0) complex [Pt(PPh₃)₄] reacts with brominated propargylic amides and esters in benzene by oxidative addition to give trans-[Br(PPh₃)₂Pt-C≡C-C(O)R] complexes whereas no reaction occurs when halogenated solvents (CH₂Cl₂, CHCl₃) are used. The cis-ligands PPh₃ can be replaced by P(ⁱPr)₃ and the bromide by trifluoroacetate. O-Alkylation of those trans-[X(PR′₃)₂Pt-C≡C-C(O)R] complexes (X = Br, CF₃COO; R′ = Ph, ⁱPr) derived from propargylic amides with MeOTf or [Me₃O]BF₄ in CH ₂Cl₂ gives the first cationic monoallenylidene complexes of platinum, trans-[X(PR′₃)₂PtC≡CC(OMe)NR ₂]⁺Y^- (Y = OTf, BF₄). In contrast, trans-[Br(PPh₃)₂Pt-C≡C-C(O)OMenthyl] derived from a propargylic ester does not react with MeOTf in CH₂Cl₂. However, in acetonitrile instead of O-methylation the substitution of acetonitrile for the bromide ligand to yield the cationic acetonitrile alkynyl platinum complex trans-[MeCN(PPh₃)₂Pt-C≡C-C(O) OMenthyl]⁺OTf^- is observed. The related palladium complexes trans-[X(PR′₃)₂Pd-C≡C-C(O)OR] (X = Br, CF₃COO; R′ = Ph, ⁱPr, R = menthyl, Et) react with MeOTf or [Et₃O]BF₄ analogously affording trans-[MeCN(PR′₃)₂Pd-C≡C-C(O)OR] ⁺Y^- (Y = OTf, BF₄).

Full text of DOI:10.1016/j.ica.2011.02.074

Inorganica Chimica Acta 374 (2011) 278–287
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Inorganica Chimica Acta
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Platinum allenylidene complexes and formation of platinum and palladium
acetonitrile alkynyl complexes
⇑
Florian Kessler, Evelyn Wuttke, Daniela Lehr, Yan Wang, Bernhard Weibert, Helmut Fischer
Fachbereich Chemie, Universität Konstanz, Fach 727, 78457 Konstanz, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
Available online 4 March 2011
The platinum(0) complex [Pt(PPh3)4] reacts with brominated propargylic amides and esters in benzene
by oxidative addition to give trans-[Br(PPh3)2Pt–C„C–C(@O)R] complexes whereas no reaction occurs
when halogenated solvents (CH2Cl2, CHCl3) are used. The cis-ligands PPh3 can be replaced by P(iPr)3
and the bromide by trifluoroacetate. O-Alkylation of those trans-[X(PR03)2Pt–C„C–C(@O)R] complexes
Dedicated to Professor Wolfgang Kaim on
the occasion of his 60th birthday.
i
(X = Br, CF3COO; R0 = Ph, Pr) derived from propargylic amides with MeOTf or [Me3O]BF4 in CH2Cl2 gives
the first cationic monoallenylidene complexes of platinum, trans-[X(PR03)2Pt@C@C@C(OMe)NR2]+Yꢀ
Keywords:
Allenylidene complexes
Palladium
Platinum
Alkynyl complexes
Acetonitrile complexes
(Y = OTf, BF4). In contrast, trans-[Br(PPh3)2Pt–C„C–C(@O)OMenthyl] derived from
a propargylic
ester does not react with MeOTf in CH2Cl2. However, in acetonitrile instead of O-methylation the substi-
tution of acetonitrile for the bromide ligand to yield the cationic acetonitrile alkynyl platinum complex
trans-[MeCN(PPh3)2Pt–C„C–C(@O)OMenthyl]+OTfꢀ is observed. The related palladium complexes trans-
[X(PR03)2Pd–C„C–C(@O)OR] (X = Br, CF3COO; R0 = Ph, iPr, R = menthyl, Et) react with MeOTf or [Et3O]BF4
analogously affording trans-[MeCN(PR03)2Pd–C„C–C(@O)OR]+Yꢀ (Y = OTf, BF4).
Ó 2011 Elsevier B.V. All rights reserved.
1. Introduction
complexes of group 10 metals were unknown for a long time
although compounds of these metals – nickel, palladium and plat-
Allenylidene complexes, [LnM@C@C@C(R1)R2], are character-
ized by a linear C3 chain terminated by a sp2 hybridised carbon
atom and bonded to a ligand-metal fragment LnM [1]. The bonding
within these [LnM@C@C@C(R1)R2] complexes (Scheme 1) can vary
considerably depending on the terminal substituents R1 and R2 and
on the electronic properties of the LnM fragment.
The structural and electronic variability of this type of com-
plexes offers considerable potential as starting compound for stoi-
chiometric reactions and as catalyst precursors [2] for various
transformations such as ring closing metathesis [3], ring opening
metathesis [4], the dehydrogenative dimerization of tin hydrides
[5], and selective transetherification of substituted vinyl ethers [6].
Since the first synthesis of allenylidene complexes reported in
1976 simultaneously by Fischer et al. (M = Cr, W) [7] and Berke
(M = Mn) [8] a large number of allenylidene complexes of many
transition metals has been prepared including complexes of
titanium, chromium, tungsten, manganese, rhenium, iron, ruthe-
nium, osmium, rhodium, and iridium [1]. However, allenylidene
inum – are very often used as precursors for catalytic applications.
Only recently, the synthesis of the first palladium monoallenylid-
ene complexes by oxidative addition of terminally brominated
propargylic N,N-dimethylamide to [Pd(PPh3)4] in CH2Cl2 at ambi-
ent temperature followed by O-alkylation of the resulting complex
trans-[Br(PPh3)2Pd–C„C–C(@O)NMe2] with MeOTf, [Me3O]BF4 or
[Et3O]BF4 was reported by Kessler et al. [9]. Subsequently, also
some bisallenylidene complexes of palladium [10,11] and platinum
[11] could be prepared by alkylation of suitable
p-donor substi-
tuted bisalkynyl complexes of palladium and platinum. These
bisalkynyl complex precursors of palladium and platinum were
synthesized by transmetallation of the corresponding acetylides
from silver to palladium and platinum, respectively. In addition,
a few p-donor substituted nickel allenylidene complexes have re-
cently been characterized [12]. However, attempts to synthesize
monoallenylidene platinum complexes by applying the same meth-
odology and conditions successfully used for the preparation of
palladium monoallenylidene complexes met with failure.
We report (a) on the successful synthesis of the first
monoallenylidene complexes of platinum by a modification of
the initial procedure and (b) on the formation of unusual acetoni-
trile alkynyl complexes instead of allenylidene bromo complexes
when trans-[Br(PPh3)2M–C„C–C(@O)OR] complexes (M = Pd, Pt;
R = Et, (ꢀ)-menthyl) are treated with alkylating reagents.
⇑
Corresponding author. Tel.: +49 7531 882783; fax: +49 7531 883136.
E-mail address: helmut.fischer@uni-konstanz.de (H. Fischer).
0020-1693/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2011.02.074

F. Kessler et al. / Inorganica Chimica Acta 374 (2011) 278–287
279
R1
R1
LnM C C C
R2
R1
LnM C C C
R2
(Scheme 2). The related alkynyl complex 2b was prepared analo-
gously and obtained in 87% yield.
LnM C
C
C
R2
The subsequent alkylation of 2a at ambient temperature with a
slight excess of MeOTf proceeded smoothly and afforded the cat-
ionic allenylidene platinum complex 3a-OTf as colourless solid in
98% yield after recrystallization from CH2Cl2/Et2O mixtures
(Scheme 2). The corresponding BF4 salt; 3a-BF4, was obtained
when [Me3O]BF4 instead of MeOTf was used as the alkylating
agent. Complex 3b-OTf was synthesized accordingly.
B
C
A
R1
R2
R1
LnM C C C
R2
LnM C C C
The modification of the co-ligand sphere of these allenylidene
complexes is easiest achieved on the stage of the alkynyl com-
D
E
plexes. Since the metal-bound C atom and the terminal C atom
a
c
Scheme 1.
in allenylidene complexes are electrophilic centres (see resonance
forms B and C in Scheme 1) the additions of nucleophiles to these
centres might compete with the substitution of the co-ligands in
allenylidene complexes. Such side reactions can be avoided by
already modifying the alkynyl complexes. The addition of 2.2 equiv
of the more nucleophilic phosphine P(iPr)3 to solutions of 2a in
CH2Cl2 led to the quantitative exchange of both PPh3 ligands. The
resulting complex 4a was obtained as a colourless solid, after puri-
fication by column chromatography and recrystallization from
CH2Cl2/Et2O, in 60% yield. Complex 4a was subsequently converted
into the cationic allenylidene complex 5a-OTf by alkylation with
MeOTf (98% yield).
The trans-bromo ligand in 2a was replaced by trifluoroacetate
when Ag+[CF3COO]ꢀ was added to a solution of 2a in CH2Cl2, AgBr
instantaneously precipitated and the trifluoroacetato complex 6a
was isolated as a colourless solid in 77% yield. Alkylation of 6a with
MeOTf finally afforded the allenylidene complex 7a-OTf in 96%
yield (Scheme 3). All new alkynyl and allenylidene complexes were
characterized by spectroscopic means and by elemental analysis.
2. Results and discussion
2.1. Platinum monoallenylidene complexes
The original two-step procedure successfully applied to the
preparation of allenylidene bromo palladium complexes (first oxi-
dative addition of brominated propargylic amides to [Pd(PPh3)4] in
CH2Cl2 at room temperature followed by alkylation of the resulting
alkynyl bromo complexes) [9] could not be transferred to the syn-
thesis of corresponding allenylidene platinum complexes since all
attempts to oxidatively add brominated propargylic dimethyla-
mide to [Pt(PPh3)4] in CH2Cl2 at room temperature failed. Already
earlier [11] we observed that the formation of platinum bisalkynyl
complexes proceeds much slower than that of the corresponding
bisalkynyl complexes of palladium. Therefore, the reaction mixture
was heated to 50 °C, the reaction time was extended from 1 to 16 h
and, to allow for a higher temperature, the solvent was changed
from dichloromethane to chloroform. However, even under these
more forcing conditions the platinum alkynyl complex 2a did not
form.
The m(CC) absorption of the alkynyl complexes was found in the
range 2100–2118 cmꢀ1, at slightly higher energy than that of the
corresponding palladium complexes. Analogously to alkynyl palla-
dium complexes, on alkylation the absorption shifts toward lower
energy by 12–20 cmꢀ1 indicating an only small change in the
The oxidative addition of bromoalkynes to the 18 VE complex
[Pt(PPh3)4] has to follow a mechanism consisting of several steps:
(a) dissociation of at least one PPh3 ligand from the metal, (b) addi-
tion of the bromoalkyne to form a bromoalkyne complex followed
by (c) rearrangement to finally form the alkynyl bromo platinum
complex. Already earlier [13] it was observed that the chloro phen-
bonding within the ‘‘MCCC’’ moiety. The position of the
m(CC)
absorption of the new allenylidene platinum complexes is similar
to that of the corresponding palladium complexes.
From the observation of only one singlet in the 31P NMR spectra
it followed that the two phosphine ligands are mutually trans.
There was no indication of the presence of a cis isomer. The reso-
nances of the alkynyl ligand in the 13C NMR spectra compare well
with those of known platinum alkynyl complexes [11,15] and
ylethyne complex [(PPh3)2Pt(g
2-ClC„CPh)] (formed by reduction
of cis-[(PPh3)2PtCl2] with hydrazine hydrate followed by addition
of ClC„CPh) did not rearrange neither in dichloromethane nor in
chloroform. However, in benzene solution the isomerization to
trans-chloro phenylethynyl bis(triphenylphosphine) platinum took
place. Likewise in benzene, bromo(phenyl)ethyne was found to
quickly add at room temperature to [Pt(PPh3)4] forming bromo
phenylethynyl bis(triphenylphosphine) platinum [14].
show a high field shift of the C resonance by 8–15 ppm and of
a
the Cb resonance by 4–9 ppm relative to those of corresponding
palladium alkynyl complexes [9]. As expected, the C resonance
a
of 6a containing the electron withdrawing trifluoroacetato ligand
When [Pt(PPh3)4] was treated with bromo propargylic dimeth-
ylamide (1a) in chloroform or dichloromethane we could not
detect the corresponding alkyne complex, however, in benzene
the trans-alkynyl bromo complex 2a formed within about 2 h
and was isolated, after column chromatography, in 54% yield
trans to the alkynyl ligand is observed at highest field (C of 2a:
a
96.5 ppm; of 6a: 77.8 ppm) and the Cb resonance at lowest field
(Cb of 2a: 98.9 ppm; of 6a: 103.0 ppm). In contrast, changing the
cis ligands from PPh3 to P(iPr)3 influences these carbon resonances
only minimally.
PPh3
OMe
Br Pt C C C
PPh3
Br Pt C C C
O
O
[Pt(PPh3)4]
MeOTf or
X
Br C C C
-2 PPh3
[Me3O]BF4
R
R
R
PPh3
PPh3
1a,b
2a,b
3a-X, 3b-X
R = NMe2 (a),
(b)
X = OTf, BF4
N
Scheme 2.

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F. Kessler et al. / Inorganica Chimica Acta 374 (2011) 278–287
P(iPr)3
P(iPr)3
O
OMe
MeOTf
Br Pt C C C
OTf
Br Pt C C C
P(iPr)3
in CH2Cl2
P(iPr)3
NMe2
NMe2
4a
5a-OTf
+ 2 P(iPr)3 - 2 PPh3
PPh3
O
Br Pt C C C
PPh3
NMe2
2a
+ CF3COOAg - AgBr
PPh3
F3CCOO Pt C C C
PPh3
PPh3
OMe
O
MeOTf
F3CCOO Pt C C C
OTf
in CH2Cl2
NMe2
NMe2
PPh3
6a
7a-OTf
Scheme 3.
The formation of the cationic allenylidene complexes by alkyl-
ation of the alkynyl complexes is accompanied by a pronounced
shift of the C resonance to lower field by about 42 ppm and of
a
the Cb resonance to higher field (
D
d ꢁ 7–11 ppm). The resonances
of the C atom and of the N–CH3 groups are almost unaffected by
c
the alkylation. Similar trends have been observed on alkylation of
alkynylpentacarbonylchromate complexes to give neutral alleny-
lidene complexes [16]. The extent of these shifts and the observa-
tion of two resonances for the dimethylamino substituent in the 1H
and 13C NMR spectra (see below) confirm the importance of the
zwitterionic resonance forms B–E , especially D/E, for the overall
bond description of these cationic allenylidene complexes (Scheme
1) [16].
Two singlets for the N-bound methyl groups in the NMR spectra
of the alkynyl complexes 2a, 4a and 6a and of the allenylidene
complexes 3a-OTf, 3a-BF4, 5a-OTf and 7a-OTf indicate a rather
high barrier to rotation around the C(sp2)–N bond. From the coa-
lescence of the two signals of 2a in C2D2Cl4 at 108 °C a barrier of
D
Gà = 76 1 kJ/mol was calculated. For 4a and 6a also Gà = 76
D
1 kJ/mol was calculated. The barrier is slightly lower than that in
free propargylic dimethylamides (RC„CC(@O)NMe2, R = H, Me,
Ph: 79.6–82.1 kJ/mol) [17] and almost identical with that in the
corresponding monoalkynyl palladium complex [Br(PPh3)2Pd–
Fig. 1. Structure of complex 6a in the crystal (ellipsoids drawn at 50% level,
hydrogen atoms omitted for clarity). Important distances (Å) and angles (°) are:
Pt(1)–C(1) 1.940(6), Pt(1)–O(2) 2.078(4), Pt(1)–P(1) 2.3170(16), Pt(1)–P(2)
2.3139(15), C(1)–C(2) 1.206(8), C(2)–C(3) 1.448(8), C(3)–O(1) 1.220(7), C(3)–N(1)
1.358(8); C(1)–Pt(1)–O(2) 177.2(2), P(1)–Pt(1)–P(2) 174.48(5), Pt(1)–C(1)–C(2)
176.8(5), C(1)–C(2)–C(3) 178.1(7), C(2)–C(3)–O(1) 122.2(6), C(2)–C(3)–N(1)
116.0(5).
C„C–C(@O)NMe2] (D
Gà = 76.1 0.4 kJ/mol) [9], indicating almost
negligible interaction of the metal with the C(@O)NMe2 fragment.
The barrier to rotation around the C(sp2)–N bond in the cationic
platinum allenylidene complex 7a-OTf is even higher than in the
neutral complexes 2a, 4a and 6a. A coalescence of the N–Me sig-
nals was not observed up to 130 °C, indicating considerable C–N
double-bond character and a very important contribution of reso-
nance form E (R1 = NMe2) to the overall bond description (Scheme
spectra. In 6a the plane formed by the atoms C(3), O(1), and
N(1) and the coordination plane of platinum are almost perpen-
dicular (torsion angle: O(1)–C(3)–Pt(1)–P(1) 78.6°). The Pt–C3
chain only slightly deviates from linearity: Pt–C(1)–C(2):
176.8(5)°, C(1)–C(2)–C(3): 178.1(7)°. The Pt–C bond (1.940(6) Å)
is significantly shorter than in the bisalkynyl platinum complexes
trans-[(PPh3)2Pt(–C„C–C{@O}N(CH2)4)2] [2.003(3) Å] [11], trans-
1). The conclusion is supported by the C resonance at rather high
a
field.
The solid-state structure of alkynyl complex 6a (Fig. 1) was
additionally determined by an X-ray diffraction study. In 6a the
platinum atom is square-planar coordinated with the two phos-
phine ligands being mutually trans as already deduced from the
appearance of only one phosphorus resonance in the 31P NMR
[(PEt3)2Pt(–C„CPh)2]
[1.98(1) Å]
[18]
and
trans-[(PEt3)2
Pt(–C„CPh)(–C„C–C6H4F-p)] [1.99(1) Å] [18].

F. Kessler et al. / Inorganica Chimica Acta 374 (2011) 278–287
281
2.2. Platinum and palladium acetonitrile complexes
The reaction of the complexes 11a,b with MeOTf in acetonitrile
proceeded smoothly and similarly to that of 9a; the complexes
12a-OTf and 12b-OTf were isolated in almost quantitative yield
(96%) (Scheme 5). Surprisingly the same reactivity was observed
when complex 11a was treated in acetonitrile with [Et3O]BF4 in-
stead of MeOTf; complex 12a-BF4 was formed in quantitative yield.
Complex 13, containing the more basic P(iPr)3 ligands in cis-
position and obtained by substitution of P(iPr)3 for PPh3, reacted
analogously and afforded trans-acetonitrile alkynyl complex
14-OTf likewise in almost quantitative yield (Scheme 6).
The formation of trans-acetonitrile alkynyl complexes is not
restricted to trans-alkynyl bromo complexes as the starting
compounds. The trans-alkynyl trifluoroacetato complex 15 (pre-
pared by substitution of trifluoroacetate for the bromo ligand in
11a) reacts analogously with MeOTf in acetonitrile to form 12a-OTf.
The formation of the cationic acetonitrile complexes by substi-
tution of the bromo or trifluoroacetato ligands of the alkynyl com-
Attempts to transfer the route to N,O-substituted allenylidene
platinum complexes to O,O-substituted ones led to a surprising
result. The oxidative addition of the brominated propargylic acid
(ꢀ)-menthylester 8a (Scheme 4) to [Pt(PPh3)4] in benzene to give
the alkynyl complex 9a went smoothly. However, when MeOTf
was added to a solution of complex 9a in CH2Cl2 at room tem-
perature, the expected shift of the
m(CC) absorption in the IR
spectra towards lower energy, characteristic for the formation
of an allenylidene complex, was not observed even when a large
excess of MeOTf was used. Neither extending the reaction time,
changing the solvent from dichloromethane to chloroform and
increasing the temperature nor changing the alkylating agent (in-
stead of MeOTf [Me3O]BF4 and [Et3O]BF4 were employed) led to
the formation of an allenylidene complex. A cationic vinylidene
complex by methylation of the nucleophilic Cb atom of the alky-
nyl ligand in 9a was likewise not formed. The formation of a
mixture of vinylidene and allenylidene complexes was observed
in the reaction of [(CO)5M–C„C–C(@O)OR] (M = Cr, W; R = (ꢀ)-
menthyl, endo-bornyl) with [Me3O]BF4 [19]. Changing the
solvent to acetonitrile finally led to a reaction. Instead of an
allenylidene complex the unprecedented acetonitrile complex
10a-OTf (Scheme 4) was isolated in 81% yield. Complex
10a-OTf was not obtained when complex 9a was stirred in
acetonitrile in the absence of MeOTf.
Already earlier it has been reported that the aryl palladium
complex [I(PPh3)2Pd–C6H4I-p] reacts with AgOTf by substitution
of triflate for the iodide ligand and formation of the corresponding
triflate complex [TfO(PPh3)2Pd–C6H4I-p] and silver iodide [20]. The
coordinated triflate can be replaced by nitrogen donors (e.g. pyra-
zine or cyanopyridine) yielding charged complexes of the general
formula [L(PPh3)2Pd–C6H4I-p](OTf) (L = nitrogen donor). To the
best of our knowledge a related reaction using MeOTf instead of
AgOTf has not been described.
plexes is accompanied by a high-field shift of the C resonance of
a
about 13 ppm,
a shift of the Cb resonance to lower field
(D
d ꢁ 5 ppm) and a shift of the
m(CC) vibration to higher energy
by 9–17 cmꢀ1. The resonances of the C atom and the N–CH3
c
groups were almost unaffected by the substitution. These shifts
are more pronounced for the trans-bromo than for the trans-
trifluoroacetato complexes.
In summary, the oxidative addition of brominated propargylic
amides and esters to tetrakis(triphenylphosphine) palladium and
platinum as well as the reactivity of the corresponding alkynyl
complexes towards alkylating agents proved to be strongly sol-
vent-dependent. Whereas propargylic amides and esters smoothly
add to [Pd(PPh3)4] in dichloromethane and chloroform, no reaction
is observed when [Pt(PPh3)4] is employed. For the synthesis of
trans-[Br(PPh3)2Pt–C„C–C(@O)R] complexes unpolar benzene as
the solvent is required. The reaction behaviour of trans-
[Br(PPh3)2M–C„C–C(@O)R] towards alkylating agents in turn does
not depend on the metal (M = Pd, Pt), however, is strongly influ-
enced by the substituent R. Alkynyl complexes derived from prop-
argylic amides are readily alkylated by MeOTf or [R03O]BF4 in
dichloromethane to form cationic allenylidene complexes whereas
no reaction is observed when alkynyl complexes derived from
propargylic esters are treated with MeOTf or [R03O]BF4 in
To determine whether alkynyl palladium complexes react with
MeOTf/acetonitrile in the same way as the platinum complex 9a,
the complexes 11a and 11b were synthesized by oxidative addition
of the corresponding bromoalkyne to [Pd(PPh3)4] in dichlorometh-
ane (Scheme 5).
+
PPh3
PPh3
MeCN Pt C C C
O
O
O
[Pt(PPh3)4]
MeOTf
CH3CN
Br C C C
OR
Br Pt C C C
OTf
- 2 PPh3
OR
OR
PPh3
PPh3
8a
9a
10a-OTf
OR = O
Scheme 4.
MeOTf or
[Et3O]BF4
+
PPh3
MeCN Pd C C C
PPh3
Br Pd C C C
PPh3
O
O
O
[Pd(PPh3)4]
- 2 PPh3
Br C C C
OR
X
CH3CN
OR
OR
PPh3
8a,b
11a,b
12a,b-X
X = OTf, BF4
O
OR =
(a), OEt (b)
Scheme 5.

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F. Kessler et al. / Inorganica Chimica Acta 374 (2011) 278–287
P(iPr)3
Br Pd C C C
+
P(iPr)3
O
OR
O
MeOTf
MeCN Pd C C C
OTf
MeCN
P(iPr)3
OR
P(iPr)3
14-OTf
13
+ 2 P(iPr)3 - 2 PPh3
PPh3
Br Pd C C C
OR
O
OR = O
PPh3
11a
+ CF3COOAg - AgBr
+
PPh3
PPh3
O
O
MeOTf
MeCN
OTf
CF3COO
MeCN Pd C C C
Pd C C C
OR
OR
PPh3
PPh3
12a-OTf
15
Scheme 6.
dichloromethane. In contrast, these alkynyl complexes smoothly
react with MeOTf or [Et3O]BF4 in acetonitrile but, instead of O-
alkylation to afford allenylidene complexes, the substitution of
acetonitrile for the trans-ligand X in trans-[X(PPh3)2M–C„C–
C(@O)OR] is observed yielding cationic alkynyl complexes
trans-[MeCN(PPh3)2M–C„C–C(@O)OR]+. This type of complex
(trans-acetonitrile alkynyl complexes) containing a readily replace-
able ligand trans to an alkynyl ligand offer considerable potential
as starting material for the synthesis of carbon-rich organometallic
compounds such as metal-carbon chains.
IR: Biorad FTS 60. MS: Finnigan MAT 312. Elemental analysis:
Heraeus Elementar vario EL and Elementar vario MICRO Cube.
GC/MS analyses were made on an Agilent Technologies 5975C
MSD interfaced to an Agilent Technologies 7890A series GC. The
compounds 1a [9], 1b [9], 8b [21], and [Et3O]BF4 [22] were pre-
pared according to literature procedures. All other chemicals were
commercial products and used as supplied.
3.2. trans-Bromo{bis(triphenylphosphine)}(3-dimethylamino-3-oxy-
1-propinyl)platinum(II) (2a)
3. Experimental
A suspension of 0.75 g (0.60 mmol) of [Pt(PPh3)4] in 20 mL of
dry benzene was treated with 0.12 g (0.66 mmol) of 1a at ambient
temperature. The mixture was stirred for 2 h upon which it be-
comes an unclear solution. The solvent was removed in vacuo
and the crude product was purified by column chromatography
using CH2Cl2/acetone as the eluant. The product was recrystallized
from CH2Cl2/Et2O to obtain colourless crystals. Yield: 0.29 g
(0.32 mmol, 54%). Mp 220 °C (dec.). 1H NMR (400 MHz, CDCl3):
d 7.76–7.69 (m, 12H, o-CH), 7.45–7.35 (m, 18H, m,p-CH), 2.56
(s, 3H, NCH3), 2.14 (s, 3H, NCH3). 13C NMR (100 MHz, CDCl3):
3.1. General
All operations were performed in an inert gas atmosphere using
standard Schlenk techniques. Solvents were dried by distillation
from CaH2 (CH2Cl2), LiAlH4 (petrol ether, hexane) or sodium (THF,
Et2O, benzene). The silica gel used for chromatography (Baker, silica
for flash chromatography) was nitrogen saturated. The yields refer
to analytically pure compounds and were not optimized. Instru-
mentation: 1H, 13C, 19F, and 31P NMR spectra were recorded with
a Bruker Avance 400 and a Varian Inova 400 spectrometer at ambi-
ent temperature. Chemical shifts are relative to the residual solvent
2
d 155.7 (C(O)NMe2), 135.0 (t, JPC = 6.4 Hz, o-C), 130.5 (p-C),
1
3
129.9 (t, JPC = 29.3 Hz, i-C), 127.8 (t, JPC = 5.4 Hz, m-C), 98.9
3
2
(t, JPC = 2.5 Hz, Pt–C„C), 96.5 (t, JPC = 14.4 Hz, Pt–C„C), 37.3
(NCH3), 33.2 (NCH3). 31P NMR (162 MHz, CDCl3):
20.0
(1JPPt = 2576 Hz). IR (CH2Cl2): (C„C) = 2112 cmꢀ1
UV–Vis
(CH2Cl2): kmax (nm) (log ) 260 (4.470). FAB-MS: m/z (%) 896
peaks or tetramethylsilane (1H, 13C) or 100% H3PO4 31P). For the
(
NMR spectra of the complexes containing a menthyl substituent
the following numbering scheme has been applied:
d
m
.
e
(100) [M+], 816 (30) [(MꢀBr)+], 717 (90) [(M–Br–CCC(O)NMe2)+].
Anal. Calc. for C41H36BrNOP2Ptꢂ0.75CH2Cl2 (895.67): C, 52.27; H,
3.94; N, 1.46. Found: C, 52.17; H, 3.98; N, 1.42%.
7
2
6
3
5
1
3.3. trans-Bromo{bis(triphenylphosphine)}(3-N,N-
tetramethylenamino-3-oxy-1-propinyl)platinum(II) (2b)
O
9
4
A suspension of 0.37 g (0.30 mmol) of [Pt(PPh3)4] in 20 mL of
dry benzene was treated with 70 mg (0.33 mmol) of 1b at ambient
temperature. The mixture was stirred for 2 h upon which it became
8
10

F. Kessler et al. / Inorganica Chimica Acta 374 (2011) 278–287
283
an unclear solution. The solvent was removed in vacuo and the
3.6. trans-Bromo{bis(triphenylphosphine)}(3-N,N-
crude product was purified by column chromatography using
petroleum ether/CH2Cl2 and then CH2Cl2/acetone as the eluant.
The product was recrystallized from CH2Cl2/Et2O to give colourless
crystals. Yield: 0.24 g (0.26 mmol, 87%). Mp 236 °C (dec.). 1H NMR
(400 MHz, CDCl3): d 7.79–7.67 (m, 12H, o-CH), 7.50–7.34 (m, 18H,
m,p-CH), 3.00 (t, J = 6.7 Hz, 2H, NCH2), 2.42 (t, J = 6.8 Hz, 2H, NCH2),
1.58 (m, 2H, CH2), 1.44 (m, 2H, CH2). 13C NMR (100 MHz, CDCl3):
tetramethylenamino-3-methoxy-1,2-propadienylidene)platinum(II)
trifluoromethanesulfonate (3b-OTf)
A solution of 50 mg (56
lmol) of 2b in 10 mL of dry CH2Cl2 was
treated with 7 L (62 mol) of MeOTf at ambient temperature. The
l
l
mixture was stirred for 1 h (IR control). The solvent was removed
in vacuo. The remaining residue was recrystallized from CH2Cl2/
2
d 154.0 (C(O)N(CH2)4), 135.0 (t, JPC = 6.2 Hz, o-C), 130.5 (p-C),
Et2O. Colourless crystals. Yield: 60 mg (55 lmol, 98%). Mp 110 °C.
1
3
129.9 (t, JPC = 29.5 Hz, i-C), 127.8 (t, JPC = 5.8 Hz, m-C), 100.3
1H NMR (400 MHz, CD2Cl2): d 7.76–7.66 (m, 12H, o-CH), 7.56–
7.44 (m, 18H, m,p-CH), 3.24 (t, J = 7.0 Hz, 2H, NCH2), 2.71 (t,
3
2
(t, JPC = 2.9 Hz, Pt–C„C), 95.8 (t, JPC = 14.5 Hz, Pt–C„C), 47.4
(NCH2), 44.7 (NCH2), 25.7 (CH2), 25.2 (CH2). 31P NMR (162 MHz,
J = 7.0 Hz, 2H, NCH2), 1.87 (m, 2H, CH2), 1.74 (m, 2H, CH2). 13C
CDCl3): d 20.2 (1JPPt = 2584). IR (CH2Cl2):
c
(C„C) = 2119 cmꢀ1
.
NMR (100.5 MHz, CD2Cl2) d 152.5 (C ), 137.6 (t, JPC = 12.8 Hz,
2
c
UV–Vis (CH2Cl2): kmax (nm) (log
e
) 261 (4.544). FAB-MS: m/z (%)
C ), 135.5 (t, 2JPC = 6.2 Hz, o-C), 132.1 (p-C), 129.5 (t, 1JPC = 30.2 Hz,
i-C), 128.9 (t, JPC = 5.6 Hz, m-C), 90.0 (t, JPC = 2.7 Hz, Cb), 60.7
(OCH3), 51.9 (NCH2), 49.3 (NCH2), 25.1 (CH2), 24.8 (CH2). 31P
NMR (162 MHz, CD2Cl2) d 19.4 (1JPPt = 2438 Hz) ppm. 19F NMR
a
922 (63) [M+], 841 (18) [(MꢀBr)+], 718 (100) [(M–Br–
CCC(@O)N(CH2)4)+]. Anal. Calc. for C43H38BrNOP2Ptꢂ0.33CH2Cl2
(921.71): C, 54.82; H, 4.03; N, 1.48. Found: C, 54.80; H, 4.05; N,
1.54%.
3
3
(376 MHz, CD2Cl2) d ꢀ78.8 (SO3CF3). IR (CH2Cl2):
m
(CCC) = 2099
cmꢀ1. UV–Vis (CH2Cl2): kmax (nm) (log
e
) 262 (4.638). FAB-MS:
m/z (%) 937 (100) [(MꢀSO3CF3)+], 674 (6) [(M–SO3CF3–PPh3)+], 593
(49) [(M–SO3CF3–PPh3–Br)+]. Anal. Calc. for C45H41BrF3NO4P2PtS
(1085.80): C, 49.78; H, 3.81; N, 1.29. Found: C, 50.30; H, 3.75; N,
1.16%.
3.4. trans-Bromo{bis(triphenylphosphine)}(3-dimethylamino-3-
methoxy-1,2-propadienylidene)platinum(II)
trifluoromethanesulfonate (3a-OTf)
A solution of 60 mg (67
l
mol) of 2a in 10 mL of dry CH2Cl2 was
3.7. trans-Bromo{bis(tri-iso-propylphosphine)}(3-dimethylamino-3-
treated with 8 L (74 mol) of MeOTf at ambient temp. The mix-
l
l
oxy-1-propynyl)platinum(II) (4a)
ture was stirred for 1 h (IR control); then the solvent was removed
in vacuo. The remaining residue was recrystallized from CH2Cl2/
At ambient temperature, a solution of 0.43 g (0.48 mmol) of 2a
in 20 mL of CH2Cl2 was treated with 0.20 mL (1.06 mmol,
2.2 equiv) of PiPr3. The progress of the reaction was monitored by
IR spectroscopy. When all of the starting material was consumed
(2 h) the solvent was removed in vacuo and the crude product
purified by column chromatography using mixtures of petroleum
ether/CH2Cl2 and then acetone as the eluant. The product was
recrystallized from CH2Cl2/Et2O. Colourless crystals. Yield: 0.20 g
(0.29 mmol, 60%). Mp 185 °C. 1H NMR (400 MHz, CDCl3): d 3.11
(s, 3H, NCH3), 3.01 (m, 6H, CH(CH3)2), 2.87 (s, 3H, NCH3), 1.34 (q,
J = 7.3 Hz, 36H, CH(CH3)2). 13C NMR (100 MHz, CDCl3): d 156.5
Et2O to yield colourless crystals. Yield: 70 mg (66 lmol, 98%). Mp
207 °C. 1H NMR (400 MHz, CD2Cl2): d 7.78–7.65 (m, 12H, o-CH),
7.57–7.43 (m, 12H, m,p-CH), 3.31 (s, 3H, OCH3), 2.88 (s, 3H,
NCH3), 2.67 (s, 3H, NCH3). 13C NMR (100 MHz, CD2Cl2) d 154.9
2
2
(C ), 138.7 (t, JPC = 12.8 Hz, C ), 135.5 (t, JPC = 6.3 Hz, o-C), 132.1
c
a
1
3
(p-C), 129.5 (t, JPC = 30.0 Hz, i-C), 129.0 (t, JPC = 5.6 Hz, m-C),
1
3
121.5 (q, JCF = 321 Hz, SO3CF3), 88.8 (t, JPC = 2.4 Hz, Cb), 61.3
(OCH3), 41.9 (NCH3), 38.0 (NCH3). 31P NMR (162 MHz, CD2Cl2) d
19.1 (1JPPt = 2436 Hz). 19F NMR (376 MHz, CD2Cl2) dꢀ78.9 (SO3CF3).
IR (CH2Cl2): m e)
(CCC) = 2095 cmꢀ1. UV–Vis (CH2Cl2): kmax (nm) (log
262 (4.539). FAB-MS: m/z (%) 911 (100) [(M–SO3CF3)+], 648 (7)
[(M–SO3CF3–PPh3)+] 567 (55) [(M–SO3CF3–PPh3–Br)+]. Anal. Calc.
for C43H39BrF3NO4P2PtS (1059.76): C, 48.73; H, 3.71; N, 1.32.
Found: C, 48.37; H, 3.94; N, 1.40%.
(C(O)NMe2), 97.6 (t, JPC = 2.0 Hz, Pt–C„C), 96.1 (t, JPC = 12.6 Hz,
3
2
1
Pt–C„C), 37.6 (NCH3), 33.7 (NCH3), 23.2 (t, JPC = 14.0 Hz,
CH(CH3)2), 19.5 (CH(CH3)2). 31P NMR (162 MHz, CDCl3): d 32.8
(1JPtP = 2375 Hz). IR (CH2Cl2): d(C„C) = 2100 cmꢀ1
.
UV–Vis
(CH2Cl2): kmax, nm (log e) [CH2Cl2]: 233 (4.277). MS (FAB): m/z
(%) 692 (95) [M+], 612 (50) [(MꢀBr)+], 515 (100) [(M–Br–
CCC(O)NMe2)+]. Anal. Calc. for C23H48BrNOP2Pt (691.56): C, 39.95;
H, 7.00; N, 2.03. Found: C, 40.26; H, 6.98; N, 2.13%.
3.5. trans-Bromo{bis(triphenylphosphine)}(3-dimethylamino-3-
methoxy-1,2-propadienylidene)platinum(II) tetrafluoroborate (3a-
BF4)
3.8. trans-Bromo{bis(tri-iso-propylphosphine)}(3-dimethylamino-3-
methoxy-1,2-propadienylidene)platinum(II)
trifluoromethanesulfonate (5a-OTf)
A solution of 0.10 g (0.11 mmol) of 2a in 10 mL of dry CH2Cl2
was treated with 20 mg (0.11 mmol) of [Me3O]BF4 at ambient tem-
perature. The mixture was stirred for 1 h (IR control) and then the
solvent was removed in vacuo. The remaining residue was recrys-
tallized from CH2Cl2/Et2O. Colourless crystals. Yield: 0.11 g
(0.11 mmol, 98%). Mp 103 °C. 1H NMR (400 MHz, CD2Cl2): d 7.76–
7.67 (m, 12H, o-CH), 7.56–7.38 (m, 12H, m,p-CH), 3.31 (s, 3H,
A solution of 80 mg (116
lmol) of 4a in 10 mL of dry CH2Cl2 was
treated with 15 L (128 mol) of MeOTf at ambient temperature.
l
l
The mixture was stirred for 1 h (IR control) and then the solvent
was removed in vacuo. Recrystallization from CH2Cl2/Et2O gave
OCH3), 2.88 (s, 3H, NCH3), 2.67 (s, 3H, NCH3). 13C NMR (100 MHz,
colourless crystals. Yield: 98 mg (114 l
mol, 98%). Mp 190 °C. 1H
2
CD2Cl2)
d
154.8 (C ), 138.3 (t, JPC = 12.8 Hz, C ), 135.4 (t,
NMR (400 MHz, CD2Cl2): d 4.18 (s, 3H, OCH3), 3.43 (s, 3H, NCH3),
3.21 (s, 3H, NCH3), 1.40–1.31 (m, 6H, CH(CH3)2), 1.25 (q,
J = 7.5 Hz, 36H, CH(CH3)2). 13C NMR (100 MHz, CD2Cl2) d 154.8
c
a
2JPC = 6.0 Hz, o-C), 132.1 (p-C), 129.4 (t, JPC = 30.0 Hz, i-C), 128.9
1
3
3
(t, JPC = 5.6 Hz, m-C), 88.8 (t, JPC = 2.6 Hz, Cb), 61.2 (OCH3), 41.8
2
1
(NCH3), 37.8 (NCH3). 31P NMR (162 MHz, CD2Cl2)
d
19.1
(C ), 137.1 (t, JPC = 10.1 Hz, C ), 121.5 (q, JCF = 320.9 Hz, SO3CF3),
c a
(1JPPt = 2434 Hz). 19F NMR (376 MHz, CD2Cl2) d ꢀ152.9 (BF4),
90.2 (Cb), 61.6 (OCH3), 42.3 (NCH3), 38.6 (NCH3), 24.2 (m,
153.0 (BF4) ppm. IR (CH2Cl2):
m
(CCC) = 2096 cmꢀ1
.
UV–Vis
CH(CH3)2), 19.9 (CH(CH3)2). 31P NMR (162 MHz, CD2Cl2) d 34.6
(CH2Cl2): kmax (nm) (log
e
) 262 (4.453). FAB-MS: m/z (%) 911 (65)
(1JPPt = 2230 Hz) ppm. 19F NMR (376 MHz, CD2Cl2)
d
ꢀ78.8
(CCC) = 2079 cmꢀ1. UV–Vis (CH2Cl2): kmax
) 265 (4.330). FAB-MS: m/z (%) 706 (100) [(M–SO3CF3)+],
546 (27) [(M–SO3CF3–P(iPr)3)+], 465 (65) [(M–SO3CF3–PiPr3–Br)+].
[(MꢀBF4)+], 646 (13) [(M–BF4–PPh3)+], 568 (100) [(M–BF4–PPh3–
Br)+]. Anal. Calc. for C42H39BBrF4NOP2Ptꢂ0.25CH2Cl2 (997.50): C,
49.81; H, 3.91; N, 1.37. Found: C, 49.72; H, 4.23; N, 1.27%.
(SO3CF3). IR (CH2Cl2):
(nm) (log
m
e

284
F. Kessler et al. / Inorganica Chimica Acta 374 (2011) 278–287
Anal. Calc. for C25H51BrF3NO4P2PtSꢂ0.5Et2O (855.67): C, 36.99; H,
(C(@O)O), 152.1 (Br–C„C), 76.8 (C1), 46.7 (C6), 40.4 (C2), 34.0
(C4), 31.2 (C3), 29.5 (C8), 26.0 (C5), 23.2 (Br–C„C), 21.8 (C10), 20.6
6.44; N, 1.60. Found: C, 37.09; H, 6.46; N, 1.43%.
(C9), 16.1 (C7). IR (CH2Cl2): (C„C) = 2198 cmꢀ1. EI-MS (70 eV):
m
3.9. trans-Trifluoroacetato{bis(triphenylphosphine)}
(3-dimethylamino-3-oxy-1-propinyl)platinum(II) (6a)
m/z (%) 287 (1) [M+], 207 (1) [(MꢀBr)+], 138 (100)
[(M–Br–CCC(O)O–H)+], 123 (59) [(M–Br–C„CC(@O)O–H–CH3)+],
95 (76) [(M–Br–CCC(O)O–H–C3H7)+]. Anal. Calc. for C13H19BrO2
(287.20): C, 54.37; H, 6.67. Found: C, 54.09; H, 6.71%.
A solution of 0.42 g (0.47 mmol) of 2a and 0.10 g (0.47 mmol) of
CF3COOAg in 20 mL of dry CH2Cl2 was stirred for 2 h at ambient
temp. The precipitate (AgBr) that formed was filtered off. The sol-
vent of the crude reaction mixture was removed in vacuo. Crystal-
lization of the crude product from CH2Cl2/Et2O gave 0.34 g
(0.36 mmol, 77%) of 6a as colourless crystals. Mp 226 °C. 1H NMR
(400 MHz, CDCl3): d 7.78–7.69 (m, 12H, o-CH), 7.47–7.36 (m,
18H, m,p-CH), 2.53 (s, 3H, NCH3), 1.88 (s, 3H, NCH3). 13C NMR
3.12. trans-Bromo{bis(triphenylphosphine)}(3-(ꢀ)-menthyloxy-3-
oxy-1-propinyl)platinum(II) (9a)
A suspension of 0.35 g (0.28 mmol) of [Pt(PPh3)4] in 10 mL of
dry benzene was treated with 100 mg (0.36 mmol) of 8a at ambi-
ent temperature. The mixture was stirred for 2 h. Then, the solvent
was removed in vacuo and the crude product was purified by col-
umn chromatography using petroleum ether/CH2Cl2 and then
CH2Cl2/acetone as solvent mixtures. The product 9a was recrystal-
lized from CH2Cl2/Et2O to obtain colourless crystals. Yield: 0.16 g
(0.15 mmol, 57%). Mp 220 °C (dec.). 1H NMR (400 MHz, CDCl3):
d 7.78–7.68 (m, 12H, o-CH), 7.44–7.34 (m, 18H, m,p-CH), 4.34 (dt,
J = 10.9 Hz, J = 4.4 Hz, 1H, H1), 1.72 (m, 2H, H2), 1.57 (m, 2H, H4),
1.28 (m, 1H, H8), 1.13 (m, 1H, H6), 0.93 (m, 2H, H5), 0.86 (d,
J = 6.4 Hz, 3H, H9), 0.78 (d, J = 7.2 Hz, 3H, H10), 0.70 (m, 1H, H3),
0.59 (d, J = 6.9 Hz, 3H, H7). 13C NMR (100 MHz, CDCl3): d 153.8
(100 MHz, CDCl3):
d 160.3 (t, J = 37.0 Hz, CF3COO), 155.4
2
(C(O)NMe2), 135.4 (t, JPC = 6.4 Hz, o-C), 131.2 (p-C), 129.2 (t,
1JPC = 29.5 Hz, i-C), 129.0 (t, JPC = 5.5 Hz, m-C), 128.6 (t, J = 5.4 Hz,
3
3
2
CF3COO), 103.0 (t, JPC = 2.9 Hz, Pt–C„C), 77.8 (t, JPC = 14.8 Hz,
Pd–C„C), 37.5 (NCH3), 33.6 (NCH3). 31P NMR (162 MHz, CDCl3) d
21.3 (1JPPt = 2694 Hz) ppm. 19F NMR (376 MHz, CD2Cl2) d ꢀ74.3
(CF3COO). IR (CH2Cl2):
(nm) (log
m
(C„C) = 2118 cmꢀ1. UV–Vis (CH2Cl2): kmax
e
) 258 (4.290). FAB-MS: m/z (%) 929 (48) [M+], 814 (39)
[(M–CF3COO)+], 717 (100) [(M–CF3COO–CCC(O)NMe2)+]. Anal. Calc.
for C43H36F3NO3P2Ptꢂ0.75CH2Cl2 (928.77): C, 54.68; H, 3.87; N,
1.47. Found: C, 54.54; H, 3.86; N, 1.40%.
2
(C(O)OMenthyl), 135.1 (t, JPC = 6.1 Hz, o-C), 130.6 (p-C), 129.8 (t,
3
2
1JPC = 29.5 Hz, i-C), 127.9 (t, JPC = 5.1 Hz, m-C), 97.3 (t, JPC
=
3.10. trans-Trifluoroacetato{bis(triphenylphosphine)}
(3-dimethylamino-3-methoxy-1,2-propadienylidene)platinum(II)
trifluoromethanesulfonate (7a-OTf)
14.0 Hz, Pt–C„C), 73.5 (C1), 46.6 (C6), 41.0 (C2), 34.2 (C4), 31.3
(C3), 25.2 (C8), 22.9 (C5), 22.1 (C10), 20.9 (C9), 15.9 (C7) ppm, not ob-
served (Pt–C„C). 31P NMR (162 MHz, CDCl3): d 19.7 (1JPtP
=
2552 Hz). IR (CH2Cl2): m
(C„C) = 2118 cmꢀ1. UV–Vis (CH2Cl2): kmax
A solution of 0.24 g (0.26 mmol) of 6a in 20 mL of dry CH2Cl2
(nm) (log e
) 259 (4.551). FAB-MS: m/z (%) 1007 (22) [M+], 927 (11)
was treated with 31
l
L (0.28 mmol) of MeOTf at ambient temper-
[(MꢀBr)+], 719 (100) [(M–Br–CCC(O)OMenthyl)+]. Anal. Calc. for
ature. The mixture was stirred for 1 h (IR control). The solvent was
removed in vacuo. Recrystallization from CH2Cl2/Et2O gave colour-
less crystals. Yield: 0.27 g (0.25 mmol, 96%). Mp 205 °C. 1H NMR
(400 MHz, CD2Cl2): d 7.67–7.59 (m, 12H, o-CH), 7.52–7.39 (m,
12H, m,p-CH), 3.01 (s, 3H, OCH3), 2.79 (s, 3H, NCH3), 2.45 (s, 3H,
NCH3). 13C NMR (100.5 MHz, CD2Cl2): d 161.0 (s, CF3COO), 154.7
C49H49BrO2P2Pt (1006.84): C, 58.54; H, 4.91. Found: C, 58.06; H,
4.92%.
3.13. trans-Acetonitrile(3-(ꢀ)-menthyloxy-3-oxy-1-propinyl
){bis(triphenylphosphine)}platinum(II) trifluoromethanesulfonate
(10a-OTf)
2
3
(C ), 135.1 (t, JPC = 6.5 Hz, o-C), 132.6 (p-C), 129.5 (t, JPC = 5.4 Hz,
c
1
1
m-C), 127.8 (t, JPC = 29.9 Hz, i-C), 121.6 (q, JCF = 322 Hz, SO3CF3),
A solution of 0.14 g (0.14 mmol) of 9a in 20 mL of dry acetoni-
trile was treated with 17 lL (0.15 mmol) of MeOTf at ambient tem-
2
1
121.3 (t, JPC = 13.1 Hz, C ), 116.5 (q, JCF = 291 Hz, CF3COO), 91.9
a
(t, JPC = 2.4 Hz, Cb), 61.2 (OCH3), 41.7 (NCH3), 38.3 (NCH3). 31P
perature. The mixture was stirred for 1 h. The solvent was removed
in vacuo and the remaining residue was recrystallized from
CH2Cl2/Et2O (1:4). Colourless crystals. Yield: 0.13 g (0.11 mmol,
81%). Mp 200 °C (dec.). 1H NMR (400 MHz, CD2Cl2): d 7.69–7.62
(m, 12H, o-CH), 7.60–7.50 (m, 18H, m,p-CH), 4.29 (dt, J = 10.8 Hz,
4.2 Hz, 1H, H1), 2.43 (s, 3H, CH3CN), 1.62 (m, 2H, H2), 1.55 (m,
2H, H4), 1.50 (m, 1H, H8), 1.26 (m, 1H, H6), 1.06 (m, 2H, H5), 0.82
(d, J = 6.6 Hz, 3H, H9), 0.72 (d, J = 7.0 Hz, 3H, H10), 0.64 (m, 1H,
H3), 0.48 (d, J = 6.9 Hz, 3H, H7). 13C NMR (100 MHz, CD2Cl2): d
3
NMR (162 MHz, CD2Cl2):
(376 MHz, CD2Cl2) d ꢀ74.3 (CF3COO), ꢀ78.9 (SO3CF3) ppm. IR
d
22.5 (1JPtP = 2552 Hz). 19F NMR
(CH2Cl2): m e)
(CCC) = 2104 cmꢀ1. UV–Vis (CH2Cl2): kmax (nm) (log
263 (4.507). FAB-MS: m/z (%) 943 (100) [(MꢀSO3CF3)+], 718 (47)
[(M–SO3CF3–CF3COO–CCC(O)NMe2)+], 567 (93) [(M–SO3CF3–
CF3COO–PPh3)+]. Anal. Calc. for C45H39F6NO6P2PdS (1092.88): C,
49.46; H, 3.60; N, 1.28. Found: C, 49.59; H, 3.83; N, 1.39%.
2
3.11. Bromo(ꢀ)-menthylpropiolate (8a)
134.5 (t, JPC = 6.3 Hz, o-C), 132.1 (p-C), 129.4 (CH3CN), 129.1 (t,
1
3JPC = 5.6 Hz, m-C), 127.0 (t, JPC = 30.3 Hz, i-C), 121.5 (q,
A solution of 10 mmol of (ꢀ)-menthyl propiolate in 40 mL of
acetone was treated at ambient temperature with 2.16 g
(12.0 mmol) of NBS and 150 mg (0.9 mmol) of AgNO3. After
80 min, the reaction mixture was poured onto 200 mL of ice water.
The aqueous phase was extracted three times with 50 mL of ethyl
acetate each. The combined organic extracts were dried over
MgSO4. The solid was then filtered off and the solvent was re-
moved in vacuo. The crude product was filtered over a short plug
of silica using CH2Cl2 as the eluant. Removal of the solvent gave
2.56 g (8.9 mmol, 89%) of 1c as a white solid. Mp 85 °C. 1H NMR
(400 MHz, CDCl3): d 4.71 (dt, J = 11.1 Hz, J = 4.3 Hz, 1H, H1), 1.95
(m, 2H, H2), 1.83 (m, 2H, H4), 1.62 (m, 1H, H8), 1.36 (m, 1H, H6),
0.99 (m, 2H, H5), 0.96 (m, 1H, H3), 0.85–0.83 (m, 6H, H9, H10),
0.69 (d, J = 7.0 Hz, 3H, H7). 13C NMR (100 MHz, CDCl3): d 177.5
1JCF = 320 Hz, SO3CF3), 74.5 (C1), 46.8 (C6), 40.7 (C2), 34.1 (C4),
31.2 (C3), 25.7 (C8), 23.3 (C5), 22.0 (C10), 20.7 (C9), 16.2 (C7), 2.4
(CH3CN), not observed: Pd–C„C–C. 31P NMR (162 MHz, CD2Cl2):
d 18.4 (1JPtP = 2420 Hz). 19F NMR (376 MHz, CD2Cl2): d ꢀ78.3
(SO3CF3). IR (CH2Cl2): m
(C„C) = 2138 cmꢀ1. UV–Vis (CH2Cl2): kmax
(nm) (log
e
) 263 (3.757). FAB-MS: m/z (%) 968 (5) [(MꢀOTf)+],
926 (29) [(M–OTf–CH3CN)+], 718 (100) [(M–OTf–CH3CN–
CCC(O)OMenthyl)+].
3.14. trans-Bromo{bis(triphenylphosphine)}(3-(ꢀ)-menthyloxy-3-
oxy-1-propinyl)palladium(II) (11a)
A suspension of 1.16 g (1.0 mmol) of [Pd(PPh3)4] in 25 mL of
CH2Cl2 was treated with 1.5 mmol of 8a at ambient temp. The

F. Kessler et al. / Inorganica Chimica Acta 374 (2011) 278–287
285
mixture was stirred for 30 min. The solvent was removed in vacuo
and the crude product was purified by column chromatography
using mixtures of petroleum ether/CH2Cl2 as eluant. Removal of
the solvent gave 0.91 g (0.99 mmol, 99%) of pure 11a as a yellow
solid. Mp 174 °C (dec.). 1H NMR (400 MHz, CD2Cl2): d 7.73–7.68
(m, 12H, o-CH), 7.49–7.40 (m, 18H, m,p-CH), 4.30 (dt, J = 10.9 Hz,
J = 4.7 Hz, 1H, H1), 1.63 (m, 2H, H2), 1.56 (m, 2H, H4), 1.47 (m,
1H, H8), 1.34 (m, 1H, H6), 1.13 (m, 2H, H5), 0.88 (d, J = 6.6 Hz, 3H,
H9), 0.80 (d, J = 6.6 Hz, 3H, H10), 0.70 (m, 1H, H3), 0.57 (d,
J = 6.6 Hz, 3H, H7). 13C NMR (100 MHz, CD2Cl2): d 152.7 (C(O)OR),
m/z (%) 837 (100) [(M–OTf–NCCH3)+]. Anal. Calc. for
C52H52F3NO5P2PdSꢂ2CH2Cl2 (1028.40): C, 54.13; H 4.71; N, 1.17.
Found: C, 54.39; H, 4.84; N, 1.19%.
3.17. trans-Acetonitrile(3-(ꢀ)-menthyloxy-3-oxy-1-propinyl)
{bis(triphenylphosphine)}palladium(II) tetrafluoroborate (12a-BF4)
A solution of 0.46 g (0.50 mmol) of 11a in 30 mL of dry acetoni-
trile was treated at ꢀ40 °C with 74 mg (0.50 mmol) of [Et3O]BF4.
The mixture was stirred for 60 min at ꢀ40 °C before warming up
to room temperature. The reaction was controlled by IR. When
all starting material was consumed the solvent was removed in
vacuo. The crude product was recrystallized from petroleum
ether/CH2Cl2 to yield pure 12a-BF4 as a yellow solid. Yield: 0.48 g
(0.50 mmol, 100%). Mp (85–88) °C. 1H NMR (400 MHz, CDCl3): d
7.68–7.58 (m, 12H, o-CH), 7.55–7.47 (m, 18H, m,p-CH), 4.27 (m,
1H, H1), 2.34 (s, 3H, NCCH3), 1.60 (m, 2H, H2), 1.54 (m, 2H, H4),
1.50 (m, 1H, H8), 1.33 (m, 1H, H6), 1.05 (m, 2H, H5), 0.78 (d,
J = 6.8 Hz, 3H, H9), 0.70 (d, J = 6.8 Hz, 3H, H10), 0.64 (m, 1H, H3),
0.45 (d, J = 7.2 Hz, 3H, H7). 13C NMR (100.5 MHz, CDCl3): d 152.0
(C(O)OR), 134.0 (o-C), 131.6 (p-C), 128.8 (m-C), 127.7 (i-C), 106.2
2
3
135.2 (t, JPC = 6.4 Hz, o-C), 131.0 (p-C), 128.4 (t, JPC = 5.6 Hz,
m-C), 74.0 (C1), 47.0 (C6), 41.3 (C2), 34.5 (C4), 31.7 (C3), 25.7 (C8),
23.3 (C5), 22.1 (C10), 20.9 (C9), 16.0 (C7), not observed: Pd–C„C,
i-C. 31P NMR (162 MHz, CD2Cl2):
d
24.6. IR (CH2Cl2):
m
(C„C) = 2115 cmꢀ1
.
UV–Vis (CH2Cl2): kmax (nm) (log 301
e)
(4.279). FAB-MS: m/z (%) 837 (4) [(MꢀBr)+], 633 (22)
[(M–CCC(O)OMenthyl–Ph)+], 367 (30) [(M–Br–CCC(O)OMenthyl–
PPh3)+]. Anal. Calc. for C49H49BrO2P2Pd (918.20): C, 64.10; H, 5.38.
Found: C, 64.03; H, 5.41%.
3.15. trans-Bromo{bis(triphenylphosphine)}(3-ethoxy-3-oxy-1-
propinyl)palladium(II) (11b)
2
(Pd–C„C), 91.7 (t, JPC = 13.1 Hz, Pd–C„C), 74.2 (C1), 46.4 (C6),
40.4 (C2), 33.8 (C4), 30.9 (C3), 25.4 (C8), 23.0 (C5), 21.7 (C10), 20.4
(C9), 15.8 (C7), 1.45 (CH3CN). 31P NMR (161.8 MHz, CDCl3): d
22.9. 19F NMR (376 MHz, CDCl3) d ꢀ152.6 (BF4). IR (CH2Cl2):
A suspension of 1.16 g (1.0 mmol) of [Pd(PPh3)4] in 25 mL of
CH2Cl2 was treated with 1.5 mmol of 8b at ambient temp. The mix-
ture was stirred for 30 min. The solvent was removed in vacuo and
the crude product was purified by column chromatography using
mixtures of petroleum ether/CH2Cl2 as the eluant. Removal of the
solvent gave 0.72 g (0.89 mmol, 89%) of pure 11b as an orange-
coloured solid. 1H NMR (400 MHz, CD2Cl2): d 7.75–7.72 (m, 12H,
o-CH), 7.43–7.38 (m, 18H, m,p-CH), 3.77 (q, 2H, J = 7.2 Hz, CH2),
1.04 (t, J = 7.2, 3H, CH3). 13C NMR (100 MHz, CD2Cl2): d 153.0
m
(C„C) = 2133 cmꢀ1 (CO) = 1686 cmꢀ1. UV–Vis (CH2Cl2): kmax
, m
(nm) (log e) 299 (4.370). FAB-MS: m/z (%) 837 (71) [(M–BF4–
NCCH3)+]. Anal. Calc. for C51H52BF4NO2P2Pdꢂ1.5CH2Cl2 (966.15): C,
57.66; H, 5.07; N, 1.28. Found: C, 57.16; H, 5.18; N, 1.22%.
3.18. trans-Acetonitrile(3-ethoxy-3-oxy-1-propinyl)
{bis(triphenylphosphine)}palladium(II) trifluoromethansulfonate
(12b-OTf)
2
3
(C(O)OR), 134.9 (t, JPC = 6.3 Hz, o-C), 131.8 (p-C), 128.0 (t, JPC
=
2
3
5.3 Hz, m-C), 110.1 (t, JPC = 14.2 Hz, C ), 101.4 (t, JPC = 5.8 Hz,
a
Cb), 60.0 (C1), 14.1 (C2). 31P NMR (162 MHz, CD2Cl2): d 23.6. IR
(CH2Cl2): m e)
(C„C) = 2115 cmꢀ1. UV–Vis (CH2Cl2): kmax (nm) (log
A solution of 0.22 g (0.27 mmol) of 11b in 70 mL of dry acetoni-
trile was treated at ambient temp with 35 lL (0.27 mmol) of
301 (4.240). FAB-MS: m/z (%) 806 (0.6) [(M+)], 726 (5.7) [(MꢀBr)+],
657 (1.2) [(M–Br–C(O)OEt)+], 630 (3.1) [(M–Br–CCC(O)OEt)+], 553
(1.4) [(M–Br–CCC(O)OEt–Ph)+]. Anal. Calc. for C41H35BrO2P2Pdꢂ
0.5CH2Cl2 (808.00): C, 58.61; H, 4.27. Found: C, 58.32; H, 4.52%.
MeOTf. The mixture was stirred for 16 h at ambient temp. The sol-
vent was removed in vacuo. The crude product was recrystallized
from petroleum ether/CH2Cl2 to yield pure 12b-OTf as yellow oil.
Yield: 0.24 g (0.26 mmol, 96%). 1H NMR (400 MHz, CDCl3): d
7.66–7.61 (m, 12H, o-CH), 7.56–7.50 (m, 18H, m,p-CH), 3.72 (q,
J = 7.2 Hz, 2H, CH2), 2.38 (s, 3H, NCCH3), 0.98 (t, J = 7.2 Hz, 3H,
CH3). 13C NMR (100.5 MHz, CDCl3): d 152.6 (C(O)OR), 134.3 (t,
3.16. trans-Acetonitrile(3-(ꢀ)-menthyloxy-3-oxy-1-propinyl)
{bis(triphenylphosphine)}palladium(II) trifluoromethanesulfonate
(12a-OTf)
3
2JPC = 6.5 Hz, o-C), 131.9 (p-C), 129.1 (t, JPC = 5.5 Hz, m-C), 127.8
1
1
(t, JPC = 20.0 Hz, i-C), 120.6 (q, JCF = 319.9 Hz, SO3CF3), 106.4
(Pd–C„C), 60.6 (CH2), 14.0 (CH3), 1.9 (CH3CN), not observed: Pd–
C„C. 31P NMR (161.8 MHz, CDCl3): d 23.0. 19F NMR (376 MHz,
A solution of 0.5 mmol of 11a in 30 mL of dry acetonitrile was
treated at ꢀ40 °C with 56
lL (0.5 mmol) of MeOTf. The mixture
was stirred for 60 min at ꢀ40 °C before warming up to room tem-
perature. The reaction was controlled by IR. When all of the start-
ing material was consumed the solvent was removed in vacuo. The
crude product was recrystallized from petroleum ether/CH2Cl2.
Yellow solid. Complex 12a-OTf can also be synthesized from 15.
Yield: 0.49 g (0.48 mmol, 96%). 1H NMR (400 MHz, CDCl3): d
7.66–7.61 (m, 12H, o-CH), 7.57–7.48 (m, 18H, m,p-CH), 4.28 (dt,
J = 10.9 Hz, 4.3 Hz, 1H, H1), 1.62 (m, 2H, H2), 1.56 (m, 2H, H4),
1.52 (m, 1H, H8), 1.33 (m, 1H, H6), 1.06 (m, 2H, H5), 0.81 (d,
J = 6.4 Hz, 3H, H9), 0.71 (d, J = 6.8 Hz, 3H, H10), 0.64 (m, 1H, H3),
0.47 (d, J = 7.2 Hz, 3H, H7). 13C NMR (100.5 MHz, CDCl3): d 152.2
CDCl3):
d
ꢀ78.2 (SO3CF3). IR (CH2Cl2):
m .
(C„C) = 2129 cmꢀ1
FAB-MS: m/z (%) 726 (72) [(M–OTf–NCCH3)+]. Anal. Calc. for
C
44H38F3NO5P2PdSꢂCH2Cl2 (918.21): C, 53.88; H, 4.02; N, 1.40.
Found: C, 53.57; H, 4.30; N, 2.28%.
3.19. trans-Bromo{bis(tri-iso-propylphosphine)}(3-(ꢀ)-menthyloxy-
3-oxy-1-propinyl)palladium(II) (13)
A solution of 0.92 g (1 mmol) of 11a in 50 mL of dry CH2Cl2 was
treated with 0.42 mL (2.2 mmol) of P(iPr)3 at ambient temp. The
mixture was stirred for 60 min. The solvent of the crude reaction
mixture was removed in vacuo. The crude product was purified
by column chromatography on silica using mixtures of ether/ace-
tone as eluant. Removal of the solvent gave 0.61 g (0.86 mmol,
86%) of 13 as yellow solid. Mp 92 °C. 1H NMR (400 MHz, CD2Cl2):
d 4.58 (td, J = 10.9 Hz, J = 4.7 Hz, 1H, H1), 2.88 (m, 6H, CH(CH3)2),
1.97 (m, 1H, H8), 1.85 (m, 2H, H2), 1.64 (m, 2H, H4), 1.35 (m, 6H,
CH(CH3)2), 1.34 (m, 3H, H5, H6), 0.87 (d, J = 6.6 Hz, 3H, H9), 0.86
2
(C(O)OR), 134.2 (t, JPC = 6.4 Hz, o-C), 131.8 (p-C), 129.0 (t,
1
3JPC = 5.4 Hz, m-C), 127.8 (t, JPC = 26.1 Hz, i-C), 120.4 (q,
3
1JCF = 319.7 Hz, SO3CF3), 106.7 (t, JPC = 6.6 Hz, Pd–C„C), 91.1 (t,
2JPC = 14.0 Hz, Pd–C„C), 74.5 (C1), 46.7 (C6), 40.6 (C2), 34.0 (C4),
31.1 (C3), 25.6 (C8), 23.1 (C5), 21.9 (C10), 20.6 (C9), 16.0 (C7), 2.0
(CH3CN). 31P NMR (161.8 MHz, CDCl3):
d
23.0. 19F NMR
(376 MHz, CDCl3): d ꢀ78.3 (SO3CF3). IR (CH2Cl2):
m(C„C) = 2132
) 300 (4.331). FAB-MS:
cmꢀ1. UV–Vis (CH2Cl2): kmax (nm) (log
e

286
F. Kessler et al. / Inorganica Chimica Acta 374 (2011) 278–287
(d, J = 6.6 Hz, 3H, H10), 0.91 (m, 1H, H3), 0.73 (d, J = 7.0 Hz, 3H, H7).
3.22. X-ray structure analysis of 6a
13C NMR (100 MHz, CD2Cl2):
d 153.6 (C(O)OR), 104.6 (t,
3
2JPC = 11.5 Hz, Pd–C„C), 102.0 (t, JPC = 4.3 Hz, Pd–C„C), 74.2
(C1), 47.1 (C6), 40.9 (C2), 34.2 (C4), 31.3 (C3), 26.3 (C8), 24.4 (t,
1JPC = 11.0 Hz, CH(CH3)2), 23.5 (C5), 22.0 (C10), 20.7 (C9), 19.9
(CH(CH3)2), 16.4 (C7). 31P NMR (162 MHz, CD2Cl2): d 42.1. IR
Single crystals suitable for X-ray structure analyses of 6a were
grown from CH2Cl2/Et2O at ambient temperature. The measure-
ments were performed with a crystal mounted on a glass fibre on
a Stoe IPDS II diffractometer (graphite monochromator, Mo Ka, radi-
(CH2Cl2):
m
(C„C) = 2111 cmꢀ1
;
m
(CO) = 1676 cmꢀ1
.
UV–Vis
ation, k = 0.71073 Å). The structure was solved by the Patterson
methods, using the SHELXTL-97 program package [23]. The position
of the hydrogen atoms were calculated by assuming ideal geometry
and their coordinates were refined together with those of the at-
tached carbon atoms as riding-model. All other atoms were refined
anisotropically. Data for 6a: C43H36F3NO3P2Pt, Mr = 928.77, colour-
less block (0.2 ꢃ 0.3 ꢃ 0.4 mm3), monoclinic, space group C2/c,
a = 21.839(4) Å, b = 15.534(3) Å, c = 24.645(5) Å, b = 106.35(3)°,
(CH2Cl2): kmax (nm) (log
e
) 284 (4.126). FAB-MS: m/z (%) 713 (10)
[M+], 634 (36) [(MꢀBr)+], 590 (23) [(M–Br–iPr)+], 451 (100) [(M–
Br–C(O)OMenthyl)+], 425 (34) [(M–Br–CCC(O)OMenthyl)+]. Anal.
Calc. for C31H61BrO2P2Pd (714.10): C, 52.14; H, 8.61. Found: C,
52.28; H, 8.63%.
3.20. trans-Acetonitrile(3-(ꢀ)-menthyloxy-3-oxy-1-propinyl)
{bis(triisopropylphosphine)}palladium(II) trifluoromethanesulfonate
(14-OTf)
V = 8023(3) Å3, Z = 8, dcalcd = 1.608 g cmꢀ3
, F(0 0 0) = 3848, l =
3.699 mmꢀ1, 2Hmax = 52.6°, index ranges ꢀ27 6 h 6 26, ꢀ19 6
k 6 19, ꢀ30 6 l 6 30, 53 729 data (8072 unique), R(int) = 0.0711,
A solution of 0.29 g (0.4 mmol) of 13 in 30 mL of dry acetonitrile
492 parameters, R1 (I > 2
r(I)) = 0.0396, wR2 = 0.0902, goodness of
q
was treated at ꢀ40 °C with 45
l
L (0.4 mmol) of MeOTf. The mix-
fit on F2 = 1.105,
D
qmax
(D
min) = 4.080 (ꢀ1.228) e Åꢀ3
.
ture was stirred for 60 min at ꢀ40 °C before warming up to room
temperature. The reaction was controlled by IR. When all starting
material was consumed the solvent was removed in vacuo. The
crude product was recrystallized from petroleum ether/CH2Cl2 to
yield pure 14-OTf as brown solid. Yield: 0.32 g (0.39 mmol, 98%).
Mp 128–130 °C. 1H NMR (400 MHz, CDCl3): d 4.56 (td, J = 10.8 Hz,
4.4 Hz, 1H, H1), 2.60 (m, 6H, CH(CH3)2), 2.12 (s, 3H, CH3), 1.93
(m, 1H, H8), 1.75 (m, 2H, H2), 1.61 (m, 2H, H4), 1.34 (m, 36H,
CH(CH3)2), 1.30 (m, 3H, H5, H6), 0.90 (m, 1H, H3), 0.84 (m, 6H, H9,
H10), 0.69 (d, J = 7.2 Hz, 3H, H7). 13C NMR (100.5 MHz, CDCl3): d
Acknowledgement
Support of this work by the Wacker-ChemieAG (gift of
chemicals) is gratefully acknowledged.
Appendix A. Supplementary material
CCDC 809233 (6a) contains the supplementary crystallographic
data for this paper. These data can be obtained free of charge from
The Cambridge Crystallographic Data Centre via www.ccdc.cam.
ac.uk/data_request/cif. Supplementary data associated with this
article can be found, in the online version, at doi:10.1016/
j.ica.2011.02.074.
3
152.7 (C(O)OR), 128.0 (CH3CN), 105.6 (t, JPC = 7.8 Hz, Pd–C„C),
2
92.3 (t, JPC = 21.5 Hz, Pd–C„C), 74.9 (C1), 47.0 (C6), 40.7 (C2),
1
34.0 (C4), 31.2 (C3), 26.5 (C8), 24.4 (t, JPC = 18.0 Hz, CH(CH3)2),
23.6 (C5), 21.8 (C10), 20.4 (C9), 19.4 (CH(CH3)2), 16.4 (C7), 3.4
(CH3CN), not observed: SO3CF3. 31P NMR (161.8 MHz, CDCl3): d
46.2. 19F NMR (376 MHz, CDCl3): d ꢀ78.3 (SO3CF3). IR (CH2Cl2,):
References
m
(C„C) = 2127 cmꢀ1 (CO) = 1685 cmꢀ1. UV–Vis (CH2Cl2): kmax
; m
(nm) (log e) 276 (4.209). FAB-MS: m/z (%) 634 (35) [(M–OTf–
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A
suspension of 0.63 g (0.69 mmol) of 11a and 0.15 g
(0.69 mmol) of CF3COOAg in 30 mL of dry CH2Cl2 was stirred for
30 min at room temperature. A precipitate (AgBr) formed and
was filtered off. The solvent of the crude reaction mixture was
removed in vacuo. The crude product was purified by column
chromatography on silica using mixtures of CH2Cl2/acetone as elu-
ant. Removal of the solvent gave 0.58 g (0.61 mmol, 88%) of 15 as
yellow solid. Mp 85 °C. 1H NMR (400 MHz, CD2Cl2): d 7.73–7.63
(m, 12H, o-CH), 7.45–7.35 (m, 18H, m,p-CH), 4.22 (dt, J = 10.9 Hz,
J = 4.7 Hz, 1H, H1), 1.62 (m, 5H, H2, H4, H8), 1.35 (m, 1H, H6), 1.14
(m, 2H, H5), 0.79 (d, J = 6.6 Hz, 3H, H9), 0.70 (d, J = 6.6 Hz, 3H,
H10), 0.54 (m, 1H, H3), 0.45 (d, J = 6.6 Hz, 3H, H7). 13C NMR
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Angew. Chem., Int. Ed. 4 (2002) 2602.
2
(100 MHz, CD2Cl2): d 134.6 (t, JPC = 6.7 Hz, o-C), 130.8 (p-C),
1
3
129.0 (t, JPC = 25.5 Hz, m-C), 128.4 (t, JPC = 5.3 Hz, m-C), 74.0
(C1), 46.8 (C6), 40.7 (C2), 34.1 (C4), 31.2 (C3), 25.5 (C8), 23.1 (C5),
22.0 (C10), 20.8 (C9), 16.1 (C7), not observed: Pd–C„C–C, F3CCO.
31P NMR (162 MHz, CD2Cl2):
2123 cmꢀ1
d
23.5. IR (CH2Cl2):
m(C„C) =
;
m
(CO) = 1680 cmꢀ1. UV–Vis (CH2Cl2): kmax (nm) (log
e)
299 (4.417). FAB-MS: m/z (%) 838 (54) [(M–CF3COO)+], 760 (8)
[(M–CF3COO–Ph)+], 655 (45) [(M–PPh3)+], 552 (18) [(M–CF3COO–
Ph–CCC(O)OMenthyl)+], 470 (100) [(M–PPh3–C(O)OMenthyl)+].
Anal. Calc. for C51H49F3O4P2Pd (951.31): C, 64.39; H, 5.19. Found:
C, 64.38; H, 5.58%.

F. Kessler et al. / Inorganica Chimica Acta 374 (2011) 278–287
287
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