Ethynyltolan platinum complexes with (arylalkynyl)phosphane ligands

Article abstract of DOI:10.1002/ejic.200700127

The ethynyltolan mononuclear complexes cis-[Pt-(C≡CC ₆H₄C≡CPh)₂(PPh₂C≡CR) ₂] [R = tol (2), C₆H₄C≡CPh (3)], which contain (arylalkynyl)phosphane ligands, were prepared, and the X-ray molecular structure of 2 was determined. The reaction of 2 and 3 with cis-[Pt(C ₆F₅)₂(thf)₂] (thf = tetrahydrofuran) in the appropriate molar ratio gave the dinuclear platinum derivatives cis-[{Pt(PPh₂C≡CR)₂(μ-η¹: η²-C^α,C^β-C≡CC ₆H₄C≡CPh)₂}Pt(C₆F ₅)₂] [R = tol (4), C₆H₄C≡CPh (5)] and the trinuclear derivatives [{Pt(μ-η¹: η²-C^α,C^β-C≡CC ₆H₄C≡CPh)₂(μ-1κP: 2η²-C^α,C^β-PPh ₂C≡CR)₂}{Pt(C₆F₅) ₂}₂] [R = tol (6), C₆H₄C≡CPh (7)], which are stabilized by a double ethynyltolan bridging system or a mixed ethynyltolan/alkynylphosphane bridging system, respectively. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.

Full text of DOI:10.1002/ejic.200700127

FULL PAPER
DOI: 10.1002/ejic.200700127
Ethynyltolan Platinum Complexes with (Arylalkynyl)phosphane Ligands
Ana García,[a] Elena Lalinde,*[a] and M. Teresa Moreno[a]
Keywords: Alkyne ligands / Phosphane ligands / Platinum / X-ray diffraction
The
ethynyltolan
mononuclear
complexes
cis-[Pt-
(5)] and the trinuclear derivatives [{Pt(µ-η1:η2-Cα,Cβ-
CϵCC6H4CϵCPh)2(µ-1κP:2η2-Cα,Cβ-PPh2CϵCR)2}{Pt(C6F5)2}2]
[R = tol (6), C6H4CϵCPh (7)], which are stabilized by a
(CϵCC6H4CϵCPh)2(PPh2CϵCR)2] [R = tol (2), C6H4CϵCPh
(3)], which contain (arylalkynyl)phosphane ligands, were
prepared, and the X-ray molecular structure of 2 was deter- double ethynyltolan bridging system or a mixed ethynyl-
mined. The reaction of 2 and 3 with cis-[Pt(C6F5)2(thf)2] (thf
= tetrahydrofuran) in the appropriate molar ratio gave the
dinuclear platinum derivatives cis-[{Pt(PPh2CϵCR)2(µ-η1:η2-
Cα,Cβ-CϵCC6H4CϵCPh)2}Pt(C6F5)2] [R = tol (4), C6H4CϵCPh
tolan/alkynylphosphane bridging system, respectively.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2007)
Introduction
form bridges, the η2-alkyne adducts [{Pt(C6F5)2(µ-κP:η2-
PPh2CϵCR)2}{Pt(C6F5)2}] (R = Ph, tol), which are gener-
ated at low temperature, evolve through an unexpectedly
easy sequential insertion of both PPh2CϵCR molecules
into a Pt–C6F5 bond to form unusual µ-2,3-bis(diphenyl-
phosphanyl)-1,3-butadien-1-yl dinuclear complexes.[4,8]
However, when X is a group with a greater tendency to act
as a bridging ligand (X = Cl, CϵCRЈ) these groups com-
pete with the η2-bonding capacity of the PPh2CϵCR group
to coordinate the “Pt(C6F5)2” fragment and only poly-
metallic species with X or mixed X/PPh2CϵCR bridging
systems are obtained.[2,3] In particular, several homo- and
heterodimetallic complexes stabilized by double alkynyl
bridging systems, such as cis-[{Pt(PPh2CϵCR)2(µ-η1:η2-
CϵCRЈ)2}Pt(C6F5)2], and unusual symmetrical cis-[{Pt-
(PPh2CϵCtBu)2(µ3-η2-CϵCPh)2}{Pt(C6F5)2}2] and cis-
[{Pt(µ-κP:η2-PPh2CϵCR)2(µ-η2-CϵCtBu)2}{Pt(C6F5)2}2]
trimetallic species, have been isolated with the mononuclear
alkynylplatinum complexes cis-[Pt(CϵCRЈ)2(PPh2CϵCR)2]
(RЈ, R = Ph, tBu) using 1:1 or 1:2 molar ratios, respectively,
thereby indicating the following order of bonding capa-
bility: CϵCRЈ Ͼ P-bonded PPh2CϵCR and CϵCPh Ͼ
CϵCtBu fragments.[3] As an extension of this work to eth-
ynyltolan systems {when referring to ethynyltolan as ligand,
its deprotonated anion [(phenylethynyl)phenyl]ethynide is
meant}, we report here the preparation and characterisa-
tion of the neutral complexes cis-[Pt(CϵCC6H4CϵCPh)2-
(PPh2CϵCR)2] [R = tol (2), C6H4CϵCPh (3)], which are
stabilized by (arylalkynyl)phosphanes. Furthermore, to gain
more insight into the synthetic possibilities of the ethynylto-
lan and (arylalkynyl)phosphane ligands, especially a com-
parison of the reactivity of inner and outer alkynyl func-
tions, we have investigated the reactivity of these complexes
towards cis-[Pt(C6F5)2(thf)2].
The ability of alkynylphosphanes (PPh2CϵCR) to bind
several metal centres through single P-complexation and/or
π-coordination has been well documented.[1–16] Further-
more, these ligands have revealed an interesting reactivity
in transition-metal chemistry, such as insertion into reactive
M–H or M–C bonds,[17–25] intramolecular coupling reac-
tions[10,26–29] or P–C bond cleavage to afford alkynide
(CϵCR) and phosphide (PPh2) fragments,[6,12,30–35] which
are often involved in subsequent coupling or insertion reac-
tions.[36–39] In addition, simple P-coordination of alkynyl-
phosphanes polarizes the electron density of the alkyne
function by concentrating it on the Cα atom, which favours
its interaction with electrophilic and nucleophilic substrates
such as water,[40,41] ethanol,[42,43] HX,[44–46] PPh2H[47] or
amines.[7,48] PPh2CϵC–X–CϵCR ligands are able to offer
higher coordination and reactivity possibilities due to the
extension of the delocalised π-system. However, they have
only been used as precursors of polymetallic com-
plexes[10,15,49–52] and in P–C bond activation or intramolec-
ular coupling reactions[51,53–55] on a few occasions.
With the aim of exploring the η2-bonding capability of
two P-coordinated diphenylphosphane ligands towards a
second metal centre as a way of inducing alkyne coupling,
we have previously studied the reactivity of cis-
[MX2(PPh2CϵCR)2] (M = Pd, Pt; X = Cl,[2] C6F5,[4,8,11]
CϵCRЈ;[3] R = Ph, tol, tBu; RЈ = Ph, tBu) towards the
solvate complex cis-[Pt(C6F5)2(thf)2] (thf = tetrahydro-
furan). When X is a C6F5 group with a low tendency to
[a] Departamento de Química – Grupo de Síntesis Química de La
Rioja, UA-CSIC Universidad de La Rioja,
26006 Logroño, Spain
Fax: +34-941-299621
E-mail: elena.lalinde@unirioja.es
Eur. J. Inorg. Chem. 2007, 3553–3560
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
3553

A. García, E. Lalinde, M. T. Moreno
FULL PAPER
tem [CαЈ: δ = 80.1 (2) and 82.7 ppm (3); CβЈ: δ = 108.6 (2)
Results and Discussion
and 107.4 ppm (3)]. The coupling constants |1JCαЈ,P
+
|
The precursor derivative cis-[Pt(CϵCC6H4CϵCPh)2-
(cod)] (1) was obtained using a similar procedure to that
4
3JCαЈ,P| [103.4 (2) and 100.2 Hz (3)] and |2JCβЈ,P + JCβЈ,P
[15.1 (2) and 14.8 Hz (3)] could also be calculated. The Cα
and Cβ alkynyl resonances also appear as the A part of an
AXXЈ system, with Cα [δ = 105.2 (2) and 104.5 ppm (3)]
appearing as a doublet of doublets [|2JCα,Ptrans + 2JCα,Pcis| =
155.1 (2) and 156.2 Hz (3)] and Cβ as a three-line pattern
used for related cis-[Pt(CϵCR)2(cod)] (R = Ph,[56] tBu[57]
)
derivatives. Thus, the reaction of an ethanolic suspension
of [PtCl2(cod)] at low temperature (–30 °C) with
HCϵCC6H4CϵCPh (2 equiv.) in a solution of NaOEt
(3.7 equiv.), prepared “in situ” from a solution of Na in
absolute EtOH, yielded 1 as a white solid in low yield
(32%). Treatment of 1 with 2 equiv. of the appropriate
(arylalkynyl)phosphane (PPh2CϵCtol, PPh2CϵCC6H4Cϵ
CPh) easily led to the displacement of the cod ligand
[δ = 109.3 (|3JCβ,Ptrans + JCβ,Pcis| = 37.6 Hz; 2) and 109.4
3
(|3JCβ,Ptrans + JCβ,Pcis| = 36.4 Hz; 3) ppm]. The acetylene
3
carbon atoms of the outer fragments [C5/C6 (2) and C5,5Ј
/
C6,6Ј (3)] appear as sharp singlets [δ = 89.9, 89.4 (2) and
92.2, 89.8, 89.4, 88.3 ppm (3)] and were assigned by com-
parison to these signals in the precursor derivative [δ = 90.1,
89.4 ppm (1)]. The alkynylphosphane CαЈ resonances are
shifted upfield in both complexes with respect to those of
free PPh2CϵCR, whereas the CβЈ carbon resonances are
very close to those of the free ligands [δ(CαЈ/CβЈ) = 84.6/
107.9 (PPh2CϵCtol), 89.2/107.4 (PPh2CϵCC6H4CϵCPh)
ppm]. As a consequence, the resulting chemical shift differ-
ence (∆ = δCβЈ – δCαЈ), which can be related to the triple-
bond polarisation,[9,13,59,60] is similar in both complexes [∆
= 28.5 (2) and 24.7 ppm (3)].
and
afforded
the
disubstituted
products
cis-
tol (2),
[Pt(CϵCC6H4CϵCPh)2(PPh2CϵCR)2] [R
=
C6H4CϵCPh (3); Equation (1)]. These complexes were iso-
lated as orange-brown solids, and their spectroscopic data
(see Experimental Section) unequivocally confirmed the P-
coordination mode of the PPh2CϵCR ligands.
An X-ray diffraction study confirmed that 2 (Figure 1) is
a slightly distorted square-planar PtII complex formed by
two mutually cis-arranged ethynyltolan (CϵCC6H4-
CϵCPh) and (tolylethynyl)phosphane (PPh2CϵCtol) li-
(1)
The IR spectra of 2 and 3 show two strong ν(CϵC) gands. Selected bond lengths and angles are given in Table 1
bands: the high-frequency band [2171 cm–1 (2, 3)] located and crystallographic data in the Experimental Section.
at slightly higher wavenumbers than that in the correspond- Chemically equivalent Pt–C [2.017(4), 2.007(4) Å] and
ing free (arylalkynyl)phosphane is attributed to the ν(CϵC) CϵC {1.196(6) and 1.204(6) Å [(tolylethynyl)phosphane
stretch of the phosphane ligands, whereas the low-fre- groups]; 1.185(6), 1.198(6) and 1.194(6), 1.195(6) Å (ethyn-
quency band [2121 (2) and 2120 cm–1 (3)] is assigned to the yltolan ligands)} bond lengths are identical within experi-
inner CαϵCβ fragment of the ethynyltolan ligand. Accord- mental error, while the Pt–P bond lengths differ only
ing to this assignment, the precursor derivative cis- slightly [2.2792(11), 2.2919(11) Å]. The inner Pt–Cα–Cβ/Cα–
[Pt(CϵCC6H4CϵCPh)2(cod)] (1) shows a medium-inten- Cβ–C(C6H4) [171.9(4)/176.9(5), 173.0(4)/176.5(5)°] and
sity band at 2119 cm–1. All complexes 1–3 also show a very outer acetylenic fragments C(C6H4)–C5–C6/C5–C6–C(Ph)
weak high-frequency band (2214 cm–1), assigned to the [175.5(5)/176.9(5), 178.8(6)/177.0(6)°] of the ethynyltolan li-
outer C5ϵC6 alkyne group of the ethynyltolan ligand [see gands and the alkynyl moiety in the phosphane fragments
the Experimental Section (Figure 3) for the labelling P–CαЈ–CβЈ/CαЈ–CβЈ–C(C6H4) [171.2(4)/175.7(5), 173.6(4)/
scheme]. The phosphorus resonance in complexes 2 and 3 177.6(5)°] do not deviate significantly from linearity. These
appears as a singlet that is shifted downfield with respect values are unexceptional and similar to those found in other
to the corresponding free ligands [δ = –6.53 (2) and X-ray crystallographically characterised mononuclear P-co-
–6.27 ppm (3) vs. –33.42 (PPh2CϵCtol) and –33.27 ppm ordinated alkynylphosphane-[8,10,14,15,26,27,61,62] or σ-alk-
(PPh2CϵCC6H4CϵCPh)], with platinum coupling con- ynylplatinum[63–78] complexes. The C6H4 group and the
stants [2350 (2) and 2343 Hz (3)] comparable to those re- phenyl rings on each ethynyltolan ligand are nearly copla-
ported for mononuclear complexes having a tertiary phos- nar [dihedral angles: 2.89(15) and 10.81(17)°], which sug-
phane group trans to a terminal alkynide group.[3,58] The gests strong π-delocalisation. However, both ethynyltolan
13C{1H} NMR spectra are particularly significant. The ligands are essentially perpendicular to each other
acetylenic carbon resonances for the (arylalkynyl)phos- [92.18(17), 91.16(20)°]. The two PPh2CϵCtol units in this
phane ligands of both complexes can clearly be seen and complex exhibit a cisoidal arrangement with a dihedral an-
their assignment is mainly based on the JC,P coupling con- gle between the planes formed by both equivalent Pt–P–Cα
stants observed and also by comparison with the corre- atoms [Pt(1)–P(1)–C(33) and Pt(1)–P(2)–C(54)] of
sponding signals in the starting precursor 1 [δ = 96.9 (Cα), 51.90(15)°, which leads to a separation between both α-car-
107.8 (Cβ), 90.1, 89.4 (C5,6) ppm; see Figure 3 for assign- bon atoms of only 3.1169(72) Å. Carty et al. have suggested
ments]. The alkynylphosphane CαЈ resonances are found as a relationship between the ease of intramolecular coupling
an apparent doublet at lower frequencies than those of the of the uncoordinated alkyne triple bonds in P-coordinated
CβЈ atoms, which are found as the A part of an AXXЈ sys- alkynylphosphane ligands and the proximity of the α-car-
3554
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© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 3553–3560

Ethynyltolan Platinum Complexes with (Arylalkynyl)phosphane Ligands
FULL PAPER
bon atoms of the proximal alkyne units (less than 3.4 Å, Table 1. Selected bond lengths [Å] and angles [°] for cis-
twice the van der Waals radius of the carbon atom).[27] In
[Pt(CϵCC6H4CϵCPh)2(PPh2CϵCtol)2]·C6H6 (2·C6H6).
fact, we have recently shown that compounds cis-[Pt-
(C6F5)2(PPh2CϵCR)2] (R = Ph, tol) with “crossed” linear
alkynyl moieties and a Cα–Cα separation of 3.20(2) Å (Ph)
or 3.34(2) Å (tol) evolve thermally into naphthalene-based
Pt(1)–C(1)
Pt(1)–C(17)
Pt(1)–P(1)
Pt(1)–P(2)
P(1)–C(33)
P(2)–C(54)
C(1)–Pt(1)–C(17)
C(1)–Pt(1)–P(2)
C(17)–Pt(1)–P(1)
P(1)–Pt(1)–P(2)
Pt(1)–C(1)–C(2)
C(1)–C(2)–C(3)
C(6)–C(9)–C(10)
C(9)–C(10)–C(11)
2.017(4)
2.007(4)
2.2792(11)
2.2919(11)
1.759(5)
1.764(5)
89.55(17)
88.36(12)
88.34(12)
95.30(4)
171.9(4)
176.9(5)
175.5(5)
176.9(5)
C(1)–C(2)
1.185(6)
1.198(6)
1.194(6)
1.195(6)
1.196(6)
1.204(6)
C(9)–C(10)
C(17)–C(18)
C(25)–C(26)
C(33)–C(34)
C(54)–C(55)
Pt(1)–C(17)–C(18) 173.0(4)
C(17)–C(18)–C(19) 176.5(5)
C(22)–C(25)–C(26) 178.8(6)
C(25)–C(26)–C(27) 177.0(6)
P(1)–C(33)–C(34) 171.2(4)
C(33)–C(34)–C(35) 175.7(5)
P(2)–C(54)–C(55) 173.6(4)
C(54)–C(55)–C(56) 177.6(5)
bis(diphenylphosphane)
complexes[62]
cis-[Pt(C6F5)2-
{C10H5-1-Ph-2,3-κPPЈ(PPh2)2}] and cis-[Pt(C6F5)2{7-CH3-
C10H4-1-tol-2,3-κPPЈ(PPh2)2}] by intramolecular [2+2+2]
coupling of two adjacent PPh2CϵCR ligands, in a similar
manner to that previously observed by Carty et al. for re-
lated dichloridoplatinum(II) derivatives.[27] Similar naph-
thalene species can also be generated starting from the di-
ynyl systems cis-[Pt(C6F5)2(PPh2CϵCC6H4CϵCR)2] (R =
Ph, tBu), but only by photolysis. In contrast, photolysis of
the monoalkynyl complexes cis-[Pt(C6F5)2(PPh2CϵCR)2]
(R = Ph, tol) proceeds with parallel formation of naphtha-
lene species and the new chelating diphosphane complexes (C6F5)2] [R = tol (4), C6H4CϵCPh (5)] by η2-complexation
cis-[Pt(C6F5)2{PPh2C(Ph)=C(R)PPh(CϵCR)}] (R = Ph, of the “cis-Pt(C6F5)2” fragment with both [para-(para-phen-
tol).[62] However, in contrast to this behaviour, complex 2, ylethynyl)phenyl]alkynyl ligands. This result was not unex-
which exhibits a very short separation between the alkynyl pected and confirms previous observations of the stronger
fragments, shows no evidence of coupling either under ther- preference of the hard PtII centre towards platinaalkynyl
mal (4 h at about 225 °C) or photochemical conditions (ir- entities rather than alkynylphosphane groups.[3,11] However,
radiation of a toluene solution for 90 min at room tempera- similar reactions of 2 and 3 with 2 equiv. of cis-[Pt(C6F5)2-
ture using a 400-W Hg lamp).
(thf)2] in CH2Cl2 yielded the trinuclear derivatives cis-
[{Pt(µ-η1:η2-Cα,Cβ-CϵCC6H4CϵCPh)2(µ-1κP:2η2-Cα,Cβ-
PPh2CϵCR)2}{Pt(C6F5)2}2] [R = tol (6), C6H4CϵCPh (7)]
in which the mononuclear precursors act as symmetrical
mixed bis(cis-η2:κP:η2)-chelating tetrahapto ligands of the
two “cis-Pt(C6F5)2” units by binding through both an eth-
ynyltolan group (µ-η2-CϵCC6H4CϵCPh) and the alkyne
function of the corresponding (arylethynyl)phosphane li-
gand (µ-κP:η2, inner for 7).
Although all attempts to obtain crystals of complexes 4–
7 have proved fruitless so far, their spectroscopic data (see
Experimental Section) are in accordance with the formula-
tion shown in Scheme 1. Thus, complexes 4 and 5 show one
strong ν(CϵC) absorption at 2173 (4) and 2172 cm–1 (5),
which confirms that the alkynyl units of the PPh2CϵCR
ligands remain uncoordinated. The expected ν(CϵC) ab-
sorptions at lower frequencies, assignable to the bridging
Pt(µ-CϵCR)2Pt entity, are not observed, although this
structural feature has been found previously in other alk-
ynyl-bridged complexes.[57] However, both complexes show
an additional very weak ν(CϵC) absorption (2216 cm–1)
that is clearly due to the outer C5ϵC6 alkyne entity of these
bridging alkynyl groups. The trinuclear derivatives 6 and 7
show two high-frequency bands [one sharp at 2174 (6) and
2173 cm–1 (7) and one very weak at 2214 (6) and 2216 cm–1
Figure 1. Molecular structure of cis-[Pt(CϵCC6H4CϵCPh)2-
(PPh2CϵCtol)2] (2). Ellipsoids are drawn at the 50% probability
level. Hydrogen atoms have been omitted for clarity.
To compare the coordination possibilities of the ethyn- (7)] corresponding to uncoordinated alkyne units and weak
yltolan ligand and the alkyne function of the P-coordinated bands [2019 (6) and 2020, 1991 cm–1 (7)] assignable to the
(arylalkynyl)phosphane ligands, we studied the reactions of ν(CϵC) moiety of the η2-coordinated groups.
2 and 3 with cis-[Pt(C6F5)2(thf)2]. The results are shown in
The equivalent phosphorus atoms of the terminal alk-
Scheme 1. Treatment of cis-[Pt(CϵCC6H4CϵCPh)2- ynylphosphane ligands in the dinuclear derivatives 4 and 5
(PPh2CϵCR)2] [R = tol (2), C6H4CϵCPh (3)] with 1 equiv. appear in the 31P{1H} NMR spectra at lower frequencies [δ
of cis-[Pt(C6F5)2(thf)2] in CH2Cl2 at room temperature af- = –11.20 (4) and –10.88 ppm (5)] than those in the precur-
forded the corresponding dinuclear derivatives cis- sors [δ = –6.53 (2) and –6.27 ppm (3)]. This high-field shift
[{Pt(PPh2CϵCR)2(µ-η1:η2-Cα,Cβ-CϵCC6H4CϵCPh)2}Pt-
is similar to that previously observed for related dinuclear
Eur. J. Inorg. Chem. 2007, 3553–3560
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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3555

A. García, E. Lalinde, M. T. Moreno
FULL PAPER
Scheme 1. Synthesis of complexes 4–7.
derivatives
cis-[{Pt(PPh2CϵCR)2(µ-η1:η2-CϵCRЈ)2}Pt- η2-CϵCPh)2}{Pt(C6F5)2}2, the related ethynyltolan frag-
(C6F5)2][3] and, therefore, is in keeping with the η2-coordi- ments in [Pt](CϵCC6H4CϵCPh)2 precursors 2, 3 only em-
nation of the “cis-Pt(C6F5)2” fragment to the ethynyltolan ploy one in the formation of complexes 6 and 7, thereby
1
ligands. The magnitude of JP,Pt [2682 (4) and 2677 Hz (5)] suggesting the lower bonding capability of these latter
is slightly larger than that in the corresponding mononu- groups.
clear derivatives with terminal ethynyltolan groups [2350 (2)
The variable-temperature 19F NMR spectra of dinuclear
and 2343 Hz (3)] due to the smaller trans influence of the complexes 4 and 5 indicate a temperature dependence of
bridging ethynyltolan ligands. In accordance with the pres- the spectral pattern. To illustrate this, the temperature de-
ence of bridging four-electron (arylalkynyl)phosphane (µ- pendence of the 19F NMR spectrum of 5 in CDCl3 is shown
κP:η2) ligands in trinuclear complexes 6 and 7, both com- in Figure 2. As can be observed, the limiting low-tempera-
plexes show a considerable downfield shift of the phospho- ture spectrum is compatible with a static structure. This
rus resonance [δ = 0.19 (6) and 0.43 ppm (7)] with respect pattern of five distinct signals (1:1:1:1:1) confirms that both
to those observed in the mononuclear precursors [δ = –6.53 C6F5 groups are rigid on the NMR timescale and equiva-
(2) and –6.27 ppm (3)] and even the dinuclear derivatives, lent. Upon raising the temperature, the two o-F doublets
in which the PPh2CϵCR molecules act only as P-donor and the two m-F multiplets coalesce (above 273 K for o-F
ligands [δ = –11.20 (4) and –10.88 ppm (5)]. The platinum- and 268 K for m-F) to only one o-F doublet and one m-F
phosphorus coupling constants [2514 (6) and 2516 Hz (7)] multiplet resonance. The approximate calculated activation
are slightly larger than those observed for the starting pre- energy is similar for the ortho-fluorine (∆G‡
=
=
273K
cursors [2350 (2) and 2343 Hz (3)] but somewhat smaller 50.01 kJmol–1) and for the meta-fluorine atoms (∆G‡
268K
than those of the dinuclear complexes [2682 Hz (4) and 50.63 kJmol–1). The equivalence of the o-F atoms (and the
2677 Hz (5)]. It should be noted that the reaction of cis- m-F ones as well) at high temperature can be explained
[Pt(CϵCC6H4CϵCPh)2(PPh2CϵCR)2] [R
=
tol (2), either by assuming a rapid rotation of the C6F5 groups
C6H4CϵCPh (3)] with 2 equiv. of cis-[Pt(C6F5)2(thf)2] could around the Pt–C bonds, as previously suggested in other
have taken place with formation of cis-[{Pt(PPh2CϵCR)2- systems with “cis-Pt(C6F5)2” fragments,[79–83] or by a fast
(µ3-η2-Cα,Cβ-CϵCC6H4CϵCPh)2}{Pt(C6F5)2}2], where the intramolecular exchange of the “cis-Pt(C6F5)2” unit below
phosphane ligands act as terminal groups and both ethyn- and above the platinum coordination plane. This second
yltolan fragments act as five-electron µ3-η2 bridging li- possibility has been suggested in related derivatives[3,57,84]
gands. However, the chemical shift and coupling constant stabilized by a double alkynyl bridging system and assumes
found in the related trinuclear complex cis-[{Pt- the existence of a formal inversion of the PtC4Pt central
(PPh2CϵCtBu)2(µ3-η2-CϵCPh)2}{Pt(C6F5)2}2]
[δ
=
skeleton, which could take place via intermediate species
–20.55 ppm (1JP,Pt = 3008 Hz)][3] are clearly different to with one or two µ-η1-bonded alkynyl ligands.[85] However,
those observed in the trinuclear derivatives 6 and 7, with we note that in these complexes (4, 5) an exchange mecha-
the latter being very close to those found in the symmetric nism involving the inner alkynyl moieties of the (arylalk-
isomers
cis-[{Pt(µ-η1:η2-CϵCtBu)2(µ-1κP:2η2-PPh2Cϵ ynyl)phosphane ligands cannot be discarded. The trinuclear
CR)2}{Pt(C6F5)2}2] [δ = 0.67 to –1.96 ppm (1JP,Pt = 2488– derivatives 6 and 7 show a pattern that is consistent with
2501 Hz)].[3] These results indicate that, while the phenyl- two inequivalent C6F5 rings in which both halves are equiv-
ethynyl groups in [Pt](CϵCPh)2 derivatives use both or- alent at room temperature. The two ortho-fluorine reso-
thogonal π-acetylenic bonds in the formation of {[Pt](µ3- nances are broad at this temperature but, unfortunately,
3556
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© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 3553–3560

Ethynyltolan Platinum Complexes with (Arylalkynyl)phosphane Ligands
FULL PAPER
their extremely low stability in solution, even at low tem-
perature, has prevented us from obtaining the correspond-
ing clean variable-temperature 19F NMR spectra.
Figure 3. Labelling scheme for the carbon atoms in the ethynylto-
lan and (ethynyltolan)diphenylphosphane ligand.
Synthesis of cis-[Pt(CϵCC6H4CϵCPh)2(cod)] (1): A freshly pre-
pared mixture of HCϵCC6H4CϵCPh (432 mg, 2.138 mmol) and
sodium ethoxide (prepared from 84 mg of sodium and 20 mL of
ethanol) was added dropwise, with constant stirring, to a suspen-
sion of [PtCl2(cod)] (400 mg, 1.069 mmol) in deoxygenated ethanol
(10 mL) at –30 °C. After stirring at low temperature for 1 h, the
resulting white solid was filtered and washed with successive por-
tions of water (2ϫ5 mL) and acetone (2ϫ5 mL). Yield: 242 mg
(32%). C40H30Pt (705.8): calcd. C 68.07, H 4.28; found C 68.42, H
1
3.98. IR (Nujol): ν = 2214 (vw), 2119 (m) (CϵC) cm–1. H NMR
˜
(300.1 MHz, CDCl3, 20 °C): δ = 7.50 (m), 7.38 (m), 7.32 (m) (18
H, C6H4, Ph), 5.70 (s, JPt,H = 43 Hz, 4 H, =CH, cod), 2.58 (s, 8 H,
CH2, cod) ppm. 13C{1H} NMR (75.5 MHz, CDCl3, 20 °C): δ =
131.5 (s), 131.2 (s), 130.8 (s), 128.0 (s, C2,3,8,9), 127.9 (d, J = 16 Hz,
Figure 2. Variable-temperature 19F NMR spectra (chemical shifts
in ppm) of cis-[{Pt(PPh2CϵCC6H4CϵCPh)2(µ-η1:η2-Cα,Cβ-
CϵCC6H4CϵCPh)2}Pt(C6F5)2] (5) in CDCl3.
2
C10), 126.2 (s), 123.1 (s), 120.8 (s, C1,4,7), 107.8 (s, JC,Pt ≈ 370 Hz,
Cβ), 104.3 (s, JC,Pt = 80 Hz, =CH, cod), 96.9 (s, Cα), 90.1 (s), 89.4
(s, C5,6) ppm. ES (+, ionized with Na+) MS: m/z (%) = 727 (38)
[M+ + Na – H].
Conclusion
Synthesis of cis-[Pt(CϵCC6H4CϵCPh)2(PPh2CϵCtol)2] (2):
PPh2CϵCtol (189 mg, 0.630 mmol) was added to a solution of cis-
[Pt(CϵCC6H4CϵCPh)2(cod)] (1; 222 mg, 0.315 mmol) in CH2Cl2
(10 mL) to give an orange solution. After stirring for 1 h, the re-
sulting solution was concentrated to a small volume, and addition
of ethanol (5 mL) gave 2 as an orange-brown solid. Yield: 220 mg
(58%). C74H52P2Pt (1198.27): calcd. C 74.18, H 4.37; found C
We have reported the formation of novel (µ-
CϵCC6H4CϵCPh)2
(CϵCC6H4CϵCPh)/µ-(PPh2CϵCR)] (6, 7) bridging di-
and triplatinum complexes. In particular, the synthesis of 6
and 7, which are stabilized by a mixed bridging system,
from 2 and 3 with 2 equiv. of cis-[Pt(C6F5)2(thf)2] instead
(4,
5)
and
mixed
[µ-
73.83, H 3.98. IR (Nujol): ν = 2214 (w), 2171 (s), 2121 (s) (CϵC)
˜
cm–1. 1H NMR (300.1 MHz, CDCl3, 20 °C): δ = 7.83 (m, 8 H),
7.46 (m, 6 H), 7.28 (m) (16 H, aromatics), 7.20 (d, JH,H = 8.05 Hz,
of
the
isomeric
cis-[{Pt(PPh2CϵCR)2(µ3-η2-Cα,Cβ-
CϵCC6H4CϵCPh)2}{Pt(C6F5)2}2] is remarkable. We have
previously shown[3] that CϵCPh groups are able to act as
five-electron donors (µ3-η2-Cα,Cβ-CϵCPh) towards “cis-
[Pt(C6F5)2]”, thus suggesting that these groups present a
stronger η2 capability than the more unsaturated
CϵCC6H4CϵCPh ligands.
4 H, C6H4), 6.97 (d, JH,H = 7.65 Hz, 4 H, C6H4), 6.88 (d, JH,H
=
7.87 Hz, 4 H, C6H4), 6.84 (d, JH,H = 7.95 Hz, 4 H, C6H4), 2.33 (s,
6 H, CH3) ppm. 13C{1H} NMR (75.5 MHz, CDCl3, 20 °C): δ =
1+3
140.0 (s, C4, tol), 133.3 (AXXЈ,
J
C,P
= 12.6 Hz, o-C, PPh2), 131.7
(s), 131.2 (s), 130.2 (s), 128.5 (s), 127.9 (s), 128.0–127.8, 127.5, 123.4
(s), 119.4 (s), 117.6 (s) (aromatics), 109.3 (AXXЈ, 3JC,Ptrans + 3JC,Pcis
2
= 37.6 Hz, Cβ, ϵCβC6H4CϵCPh), 108.6 (AXXЈ, JC,P
+
4JC,P
=
=
+
15.1 Hz, CβЈ, ϵCβЈtol), 105.2 (dd, AXXЈ, JC,Ptrans
+
2JC,Pcis
2
155.1 Hz, Cα, Cαϵ), 89.9 (s), 89.4 (s, C5,6), 80.1 (d, AXXЈ, JC,P
1
3JC,P = 103.4 Hz, CαЈ, PCαЈϵ), 21.3 (s, CH3) ppm. 31P{1H} NMR
Experimental Section
1
(121.5 MHz, CDCl3, 20 °C): δ = –6.53 (s, JP,Pt = 2350 Hz) ppm.
General Remarks: All reactions were carried out under N2 using
dried solvents purified by known procedures and distilled prior to
use. IR spectra were recorded with a Perkin–Elmer FT-IR 1000
spectrometer as Nujol mulls between polyethylene sheets and NMR
spectra were recorded with a Bruker ARX 300 spectrometer.
Chemical shifts are reported in ppm relative to external standards
(SiMe4, CFCl3 and 85% H3PO4). Elemental analyses were carried
out with a Perkin–Elmer 2400 CHNS/O microanalyzer and mass
spectra were recorded with a VG Autospec spectrometer (FAB+) or
a Microflex MALDI-TOF Bruker spectrometer operating in the
linear and reflector modes using dithranol as the matrix.
FAB(+) MS: m/z (%) = 1198 (8) [M+].
Synthesis of cis-[Pt(CϵCC6H4CϵCPh)2(PPh2CϵCC6H4CϵCPh)2]
(3): Complex 3 was synthesised as an orange product according to
a procedure similar to 2 but with cis-[Pt(CϵCC6H4CϵCPh)2(cod)]
(1; 186 mg, 0.265 mmol) and PPh2CϵCC6H4CϵCPh (204 mg,
0.528 mmol). Yield: 227 mg (63%). C88H56P2Pt (1370.4): calcd. C
77.12, H 4.12; found C 76.92, H 3.80. IR (Nujol): ν = 2214 (w),
˜
2171 (m), 2120 (s) (CϵC) cm–1. 1H NMR (300.1 MHz, CDCl3,
20 °C): δ = 7.85 (m, 8 H), 7.51 (m, 12 H), 7.39–7.19 (m) (28 H,
aromatics), 6.93 (d, JH,H = 8.05 Hz, 4 H, C6H4), 6.84 (d, JH,H
=
HCϵCC6H4CϵCPh,[86]
PPh2CϵCtol,[87]
PPh2CϵCC6H4Cϵ 8.05 Hz, 4 H, C6H4) ppm. 13C{1H} NMR (75.5 MHz, CDCl3,
CPh[13] and cis-[Pt(C6F5)(thf)2][88] were prepared according to pub-
lished procedures. Figure 3 shows the labelling scheme for the car-
bon atoms in the ethynyltolan ligand and in the (ethynyltolan)di-
phenylphosphane ligand.
20 °C): δ = 133.4 (AXXЈ,
J
C,P
= 12.4 Hz, o-C, PPh2), 131.7 (s),
1+3
131.4 (s), 131.24 (s), 131.2 (s), 131.0 (s), 130.5 (s), 130.3 (s, p-C,
PPh2), 128.2 (s), 128.11 (d, J = 64 Hz, i-C, PPh2), 128.1 (s), 128.0
(s), 127.99 (s), 124.7 (s), 123.3 (s), 122.3 (s), 119.9 (s), 119.4 (s)
Eur. J. Inorg. Chem. 2007, 3553–3560
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
3557

A. García, E. Lalinde, M. T. Moreno
FULL PAPER
3
3
1
(aromatics), 109.4 (AXXЈ, three-line pattern, JC,Ptrans + JC,Pcis
=
=
+
2019 (w) (CϵC); 804 (m), 795 (m) (C6F5)X-sensitive cm–1. H NMR
36.4 Hz, Cβ, ϵCβC6H4CϵCPh), 107.4 (AXXЈ, JC,P
+
4JC,P
(300.1 MHz, CDCl3, 20 °C): δ = 7.51–7.02 (m, 46 H, aromatics),
2
14.8 Hz, CβЈ, ϵCβЈC6H4CϵCPh), 104.5 (dd, AXXЈ, JC,Ptrans
2.36 (s, 6 H, CH3) ppm. 19F NMR (282.4 MHz, CDCl3, 20 °C): δ
2
2JC,Pcis = 156.2 Hz, Cα, Cαϵ), 92.2 (s), 89.8 (s), 89.4 (s), 88.3 = –116.6 (br. s, 4 F, o-F), –117.2 (br. s, 4 F, o-F), –160.6 (t, 2 F, p-
(C5,5Ј,6,6Ј), 82.7 (d, AXXЈ, JC,P
+
3JC,P = 100.2 Hz, CαЈ, PCαЈϵ)
F), –161.1 (t, 2 F, p-F), –164.1 (br. m, 8 F, m-F) ppm. 31P{1H}
1
1
ppm. 31P{1H} NMR (121.5 MHz, CDCl3, 20 °C): δ = –6.27 (s, NMR (121.5 MHz, CDCl3, 20 °C): δ = 0.19 (s, JP,Pt = 2514 Hz)
1JP,Pt = 2343 Hz) ppm. MALDI-TOF(+) MS: m/z (%) = 1355 (100)
[M+ – CH3], 967 (80) [Pt(PPh2CϵCC6H4CϵCPh)2+].
ppm. MALDI-TOF(+) MS: m/z (%) = 1728 (18) [M+ – Pt-
+
(C6F5)2], 1296 (50) [Pt(CϵCC6H4CϵCPh)(PPh2CϵCtol)3 – H],
+
996 (60) [Pt(CϵCC6H4CϵCPh)(PPh2CϵCtol)2 – H].
Synthesis of cis-[{Pt(PPh2CϵCtol)2(µ-η1:η2-Cα,Cβ-CϵCC6H4Cϵ
CPh)2}Pt(C6F5)2] (4): cis-[Pt(C6F5)2(thf)2] (59 mg, 0.088 mmol) was
added to an orange solution of cis-[Pt(CϵCC6H4CϵCPh)2-
(PPh2CϵCtol)2] (2; 105 mg, 0.088 mmol) in CH2Cl2 (15 mL). After
stirring at room temperature for 1 h, the solvent was evaporated to
leave a small volume, and n-hexane (8 mL) was added to precipitate
4 as a brown solid. Yield: 117 mg (77%). C86H52F10P2Pt2 (1727.5):
Synthesis
of
cis-[{Pt(µ-η1:η2-Cα,Cβ-CϵCC6H4CϵCPh)2(µ-
1κP:2η2-Cα,Cβ-PPh2CϵCC6H4CϵCPh)2}{Pt(C6F5)2}2] (7): Com-
plex 7 was prepared as a brown solid according to a procedure
similar to that for compound
6
starting from cis-
[Pt(CϵCC6H4CϵCPh)2(PPh2CϵCC6H4CϵCPh)2] (3; 70 mg,
0.051 mmol) and cis-[Pt(C6F5)2(thf)2] (79 mg, 0.117 mmol). Yield:
131 mg (65%). C112H56F20P2Pt3 (2428.9): calcd. C 55.39, H 2.32;
calcd. C 59.80, H 3.03; found C 59.97, H 2.65. IR (Nujol): ν =
˜
2216 (vw), 2173 (vs) (CϵC); 804 (s), 794 (s) (C6F5)X-sensitive cm–1.
found C 55.72, H 2.61. IR (Nujol): ν = 2216 (w), 2173 (s), 2020
˜
(w), 1991 (w) (CϵC); 805 (m), 796 (m) (C6F5)X-sensitive cm–1. 1H
NMR (300.1 MHz, CDCl3, 20 °C): δ = 7.53–7.17 (m, 56 H, aro-
matics) ppm. 19F NMR (282.4 MHz, CDCl3, 20 °C): δ = –116.5
(br. s, 4 F, o-F), –117.2 (br. s, 4 F, o-F), –160.2 (t, 2 F, p-F), –160.6
(t, 2 F, p-F), –163.7 (br. m, 4 F, m-F), –164.0 (br. m, 4 F, m-F)
ppm. 31P{1H} NMR (121.5 MHz, CDCl3, 20 °C): δ = 0.43 (s, 1JP,Pt
1H NMR (300.1 MHz, CDCl3, 20 °C): δ = 7.88 (m, 8 H, Ph), 7.50
(m, 6 H), 7.34 (m, 20 H), 7.01 (m, 8 H, C6H4), 6.84 (d, JH,H
=
7.8 Hz, 4 H, C6H4), 2.36 (s, 6 H, CH3) ppm. 19F NMR (282.4 MHz,
CDCl3, 20 °C): δ = –117.2 (br. s, 4 F, o-F), –163.5 (t, 2 F, p-F),
–165.6 (br. s, 4 F, m-F) ppm. 19F NMR (282.4 MHz, CDCl3,
3
–30 °C): δ = –116.1 (m, JPt,o-F ≈ 340 Hz, 2 F, o-F), –118.4 (m,
= 2516 Hz) ppm. MALDI-TOF(+) MS: m/z (%) = 1899 (28) [M+
–
–
3JPt,o-F ≈ 430 Hz, 2 F, o-F), –162.9 (t, 2 F, p-F), –164.6 (br. m, 2 F,
m-F), –165.8 (br. m, 2 F, m-F) ppm. Signal coalescence: o-F (ap-
prox. 268 K), m-F (approx. 263 K); ∆G‡ ≈ 49.2 kJmol–1. 31P{1H}
NMR (121.5 MHz, CDCl3, 20 °C): δ = –11.20 (s, 1JP,Pt = 2682 Hz)
Pt(C6F5)2], 1731 (50) [M+ – Pt(C6F5)2 – C6F5 – H], 1369 (54) [M+
2 Pt(C6F5)2 – H], 1151 (57) [Pt(C6F5)(CϵCC6H4CϵCPh)2(PPh2-
CϵCC6H4CϵCPh+
+ H)], 967 (64) [Pt(PPh2CϵCC6H4Cϵ
CPh)2+], 766 (25) [Pt(PPh2CϵCC6H4CϵCPh)(PPh2)+].
+
ppm. FAB(+) MS: m/z (%) = 794 (55) [Pt(PPh2CϵCtol)2 – H].
X-ray Crystallography: A summary of crystal data, data collection
and refinement parameters for the structural analysis is given in
Table 2. Crystals of complex 2 were obtained at room temperature
by slow diffusion of n-hexane into a solution of the compound in
benzene. One molecule of benzene was found in the asymmetric
Synthesis of cis-[{Pt(PPh2CϵCC6H4CϵCPh)2(µ-η1:η2-Cα,Cβ-
CϵCC6H4CϵCPh)2}Pt(C6F5)2] (5): Complex 5 was prepared as a
brown solid in
a similar way to 4 starting from cis-
[Pt(CϵCC6H4CϵCPh)2(PPh2CϵCC6H4CϵCPh)2] (3; 112 mg,
0.082 mmol) and cis-[Pt(C6F5)2(thf)2] (55 mg, 0.082 mmol), and
was recrystallised from CH2Cl2/iPrOH. Yield: 52 mg (43%).
C
100H56F10P2Pt2 (1899.6): calcd. C 63.23, H 2.97; found C 63.12,
Table 2. Crystal data and structure refinement parameters for
2·C6H6.
H 2.61. IR (Nujol): ν = 2216 (w), 2172 (s) (CϵC); 804 (m), 794
˜
(m) (C6F5)X-sensitive cm–1. H NMR (300.1 MHz, CDCl3, 20 °C): δ
1
Empirical formula
Formula mass
Temperature [K]
Wavelength [Å]
Crystal system
Space group
Crystal dimensions [mm]
a [Å]
C74H52P2Pt·C6H6
1276.29
173(1)
= 7.90 (m, 8 H, Ph), 7.51–7.21 (m, 40 H, Ph), 7.00 (d, JH,H
=
8.0 Hz, 4 H, C6H4), 6.85 (d, JH,H = 8 Hz, 4 H, C6H4) ppm. 19F
NMR (282.4 MHz, CDCl3, 20 °C): δ = –117.1 (br. s, 4 F, o-F),
–163.4 (t, 2 F, p-F), –165.6 (br. s, 4 F, m-F) ppm. 19F NMR
(282.4 MHz, CDCl3, –50 °C): δ = –116.1 (m, 3JPt,o-F ≈ 340 Hz, 2 F,
0.71073
triclinic
¯
P1
3
o-F), –118.5 (m, JPt,o-F ≈ 425 Hz, 2 F, o-F), –162.6 (t, 2 F, p-F),
0.20ϫ0.20ϫ0.05
15.1950(2)
15.2180(2)
–164.4 (m, 2 F, m-F), –165.6 (m, 2 F, m-F) ppm. 19F NMR
3
(282.4 MHz, CDCl3, +50 °C): δ = –116.9 (m, JPt,o-F = 405 Hz, 4
b [Å]
c [Å]
α [°]
β [°]
16.2740(2)
F, o-F), –163.7 (t, 2 F, p-F), –165.8 (br. m, 4 F, m-F) ppm. Signal
coalescence: o-F (273 K), m-F (approx. 268 K); ∆G‡ ≈ 50.01 (o-F),
50.63 kJmol–1 (m-F). 31P{1H} NMR (121.5 MHz, CDCl3, 20 °C):
92.0880(10)
116.7850(10)
103.1010(10)
3230.12(7)
1.312
2
γ [°]
1
δ = –10.88 (s, JP,Pt = 2677 Hz) ppm. MALDI-TOF(+) MS: m/z
V [Å3]
(%)
=
1168 (27) [Pt(CϵCC6H4CϵCPh)(PPh2CϵCC6H4Cϵ
Dcalcd. [Mgm–3]
Z
CPh)2+], 983 (50) [Pt(CϵCC6H4CϵCPh)2(PPh2CϵCC6H4Cϵ
+
CPh)+], 965 (90) [Pt(PPh2CϵCC6H4CϵCPh)2 – 2 H]+, 765 (100)
µ(Mo-Kα) [mm–1]
F(000)
2.265
1292
[Pt(PPh2CϵCC6H4CϵCPh)(PPh2) – H].
θ range [°]
Tmin/max
No. of reflns. measd.
No. of obsd. reflns.
Goodness of fit on F2[a]
Final R indices [I Ͼ 2σ(I)][a]
R indices (all data)
1.54–27.92
0.895 and 0.800
52252
15294 [R(int) = 0.0678]
1.010
R1 = 0.0488, wR2 = 0.0976
R1 = 0.0784, wR2 = 0.1068
Synthesis
of
cis-[{Pt(µ-η1:η2-Cα,Cβ-CϵCC6H4CϵCPh)2(µ-
1κP:2η2-Cα,Cβ-PPh2CϵCtol)2}{Pt(C6F5)2}2] (6): A solution of cis-
[Pt(CϵCC6H4CϵCPh)2(PPh2CϵCtol)2] (2; 104 mg, 0.087 mmol)
in CH2Cl2 (15 mL) was treated at room temperature with cis-
[Pt(C6F5)2(thf)2] (135 mg, 0.200 mmol; molar ratio 1:2.3). After
stirring for 1 h, the solvent was removed in vacuo and the addition
of n-hexane (5 mL) caused the precipitation of 6 as a brown solid.
Yield: 170 mg (86%). C98H52F20P2Pt3 (2256.7): calcd. C 52.16, H
[a] R1 = Σ(|Fo| – |Fc|)/Σ|Fo|; wR2 = [Σw(Fo – Fc ) /ΣwFo ]
2 1/2; good-
2
2 2
ness of fit = {Σ[w(Fo – Fc ) ]/(Nobs – Nparam)}1/2; w = [σ2(Fo2) +
2
2 2
2.32; found C 51.78, H 2.01. IR (Nujol): ν = 2214 (vw), 2174 (s), (g1P)2 + g2P]–1, where P = [max(Fo2;0) + 2Fc ]/3.
2
˜
3558
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© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 3553–3560

Ethynyltolan Platinum Complexes with (Arylalkynyl)phosphane Ligands
FULL PAPER
[18]
D. Montlo, J. Suades, F. Dahan, R. Mathieu, Organometallics
1990, 9, 2933–2937.
L. Dupuis, N. Pirio, P. Meunier, A. Igau, D. Donnadieu, J. P.
Majoral, Angew. Chem. Int. Ed. Engl. 1997, 36, 987–989.
A. Mahieu, Y. Miquel, A. Igau, B. Donnadieu, J. P. Majoral,
Organometallics 1997, 16, 3086–3088.
P. Rosa, P. Le Floch, L. Ricard, F. Mathey, J. Am. Chem. Soc.
1997, 119, 9417–9423.
Y. Miquel, A. Igau, B. Donnadieu, J. P. Mayoral, N. Pirio, P.
Meunier, J. Am. Chem. Soc. 1998, 120, 3504–3505.
M. A. Bennett, C. J. Cobley, A. D. Rae, E. Wenger, A. C. Willis,
Organometallics 2000, 19, 1522–1533.
A. J. Edwards, S. A. Macgregor, A. D. Rae, E. Wenger, A. C.
Willis, Organometallics 2001, 20, 2864–2877.
Y. El Harouch, V. Cadierno, A. Igau, B. Donnadieu, J. P. Majo-
ral, J. Organomet. Chem. 2004, 689, 953–964.
A. J. Carty, N. J. Taylor, D. K. Johnson, J. Am. Chem. Soc.
1979, 101, 5422–5424.
D. K. Johnson, T. Rukachaisirikul, Y. Sun, N. J. Taylor, A. J.
Canty, A. J. Carty, Inorg. Chem. 1993, 32, 5544–5552.
M. Martin-Redondo, L. Scoles, B. T. Sterenberg, K. A. Uda-
chin, A. J. Carty, J. Am. Chem. Soc. 2005, 127, 5038–5039.
P. J. Low, T. M. Hayes, K. A. Udachin, A. E. Goeta, J. A. K.
Howard, G. D. Enright, A. J. Carty, J. Chem. Soc. Dalton
Trans. 2002, 1455–1464.
unit. This molecule of benzene was found to be disordered over
two positions with two consecutive carbon atoms, C(75) and C(80),
in the same position and was modelled adequately. The disordered
sets of atoms were refined with a partial occupancy of 0.50 each.
Data for 2·C6H6 were collected at low temperature (173 K) with a
Nonius κ-CCD area-detector diffractometer, using graphite-mono-
[19]
[20]
[21]
chromated Mo-Kα radiation. Data were processed using the
DENZO and SCALEPACK suite of programs.[89] The absorption
[22]
correction was performed using SORTAV.[90] The structure was
solved by Patterson and Fourier methods using the DIRDIF92
[23]
program,[91] and refined by full-matrix least squares on F2 with
SHELXL-97.[92] All non-hydrogen atoms were assigned anisotropic
[24]
displacement parameters and all hydrogen atoms were constrained
to idealised geometries by fixing isotropic displacement parameters
at 1.2-times the Uiso value of their attached carbon atom for the
phenyl hydrogen atoms and 1.5-times for the methyl groups. There
are peaks of electron density higher than 1 eÅ–3 in the final map,
but they are located very close to the platinum atoms or in the
vicinity of the solvent and have no chemical meaning. CCDC-
634038 contains the supplementary crystallographic data for this
paper. These data can be obtained free of charge from The Cam-
bridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request.cif.
[25]
[26]
[27]
[28]
[29]
[30]
[31]
[32]
[33]
[34]
[35]
[36]
A. J. Carty, Pure Appl. Chem. 1982, 54, 113–130 and references
cited therein.
Acknowledgments
D. Nuccianore, S. A. MacLaughlin, N. J. Taylor, A. J. Carty,
Organometallics 1988, 7, 106–117.
A. A. Cherkas, L. H. Randall, S. A. MacLaughlin, G. N. Mott,
N. J. Taylor, A. J. Carty, Organometallics 1988, 7, 969–977.
M. H. A. Benvenutti, M. D. Vargas, D. Braga, F. Crepioni,
B. E. Mann, S. Naylor, Organometallics 1993, 12, 2947–2954.
G. Hogarth, S. P. Redmond, J. Organomet. Chem. 1997, 534,
221–227.
A. Albinati, V. Filippi, P. Leoni, L. Marchetti, M. Pasquali, V.
Passarelli, Chem. Commun. 2005, 2155–2157.
Y. Chi, A. J. Carty, P. Blenkiron, E. Delgado, G. D. Enright,
W. Wang, S.-M. Peng, G.-H. Lee, Organometallics 1996, 15,
5269–5271.
A. J. Carty, G. Hogarth, G. Enright, G. Frapper, Chem. Com-
mun. 1997, 1883–1884.
J. E. Davies, M. J. Mays, P. R. Raithby, K. Sarveswaran, Angew.
Chem. Int. Ed. Engl. 1997, 36, 2668–2669.
E. Delgado, Y. Chi, W. Wang, G. Hogarth, P. J. Low, G. D.
Enright, S.-M. Peng, G.-H. Lee, Organometallics 1998, 17,
2936–2938.
S. E. Jacobson, N. J. Taylor, A. J. Carty, J. Chem. Soc. Chem.
Commun. 1974, 668–669.
A. J. Carty, S. Jacobson, R. T. Simpson, N. J. Taylor, J. Am.
Chem. Soc. 1975, 97, 7254–7262.
R. J. Restivo, G. Ferguson, T. W. Ng, A. J. Carty, Inorg. Chem.
1977, 16, 172–176.
M. Bardají, A. Laguna, P. G. Jones, Organometallics 2001, 20,
3906–3912.
N. J. Taylor, S. Jacobson, A. J. Carty, Inorg. Chem. 1975, 14,
2648–2653.
M. A. Bennett, J. Castro, A. J. Edwards, M. R. Kopp, E.
Wenger, A. C. Willis, Organometallics 2001, 20, 980–989.
M. A. Bennett, L. Kwan, A. D. Rae, E. Wenger, A. C. Willis,
J. Chem. Soc. Dalton Trans. 2002, 226–233.
A. J. Carty, D. K. Johnson, S. E. Jacobson, J. Am. Chem. Soc.
1979, 101, 5612–5619.
X. Liu, T. K. W. Ong, S. Selvaratnam, J. J. Vittal, A. J. P. White,
D. J. Williams, P. H. Leung, J. Organomet. Chem. 2002, 643, 4–
11.
This work was supported by the Ministerio de Educación y Ciencia
(project CTQ2005-08606-C02-02 and a grant for A. G.).
[1] M. J. Went, Polyhedron 1995, 14, 465–481 and references cited
therein.
[2] J. Forniés, E. Lalinde, A. Martín, M. T. Moreno, A. J. Welch,
J. Chem. Soc. Dalton Trans. 1995, 1333–1340.
[3] I. Ara, L. R. Falvello, S. Fernández, J. Forniés, E. Lalinde, A.
Martín, M. T. Moreno, Organometallics 1997, 16, 5923–5937.
[4] J. P. H. Charmant, J. Forniés, J. Gómez, E. Lalinde, M. T. Mor-
eno, A. G. Orpen, S. Solano, Angew. Chem. Int. Ed. 1999, 38,
3058–3061.
[37]
[38]
[39]
[5] E. Louattani, J. Suades, J. Organomet. Chem. 2000, 604, 234–
240.
[6] J. E. Davies, M. J. Mays, P. R. Raithby, K. Sarveswaran, G. A.
Solan, J. Chem. Soc. Dalton Trans. 2001, 1269–1277.
[7] X. Liu, K. F. Mok, P. H. Leung, Organometallics 2001, 20,
3918–3926.
[8] I. Ara, J. Forniés, A. García, J. Gómez, E. Lalinde, M. T. Mor-
eno, Chem. Eur. J. 2002, 8, 3698–3716.
[9] J. R. Berenguer, M. Bernechea, J. Forniés, J. Gómez, E. Lal-
inde, Organometallics 2002, 21, 2314–2324.
[10] T. Baumgartner, K. Huynh, S. Schleidt, A. J. Lough, I. Man-
ners, Chem. Eur. J. 2002, 8, 4622–4632.
[11] J. Forniés, A. García, J. Gómez, E. Lalinde, M. T. Moreno,
Organometallics 2002, 21, 3733–3743.
[12] M. J. Mays, K. Sarveswaran, G. A. Solan, Inorg. Chim. Acta
2003, 354, 21–28.
[13] J. R. Berenguer, M. Bernechea, J. Forniés, A. García, E. Lal-
inde, Organometallics 2004, 23, 4288–4300.
[14] J. R. Berenguer, M. Bernechea, J. Forniés, A. García, E. Lal-
inde, M. T. Moreno, Inorg. Chem. 2004, 43, 8185–8198.
[15] J. Forniés, A. García, B. Gil, E. Lalinde, M. T. Moreno, Dalton
Trans. 2004, 3854–3863.
[40]
[41]
[42]
[43]
[44]
[45]
[46]
[47]
[48]
[16] M. Bardají, M. T. de la Cruz, P. G. Jones, A. Laguna, J. Martí-
nez, M. D. Villacampa, Inorg. Chim. Acta 2005, 358, 1365–
1372.
[49]
[17] J. Suades, F. Dahan, R. Mathieu, Organometallics 1989, 8, 842–
C. J. Adams, M. I. Bruce, E. Horn, E. R. T. Tiekink, J. Chem.
Soc. Dalton Trans. 1992, 1157–1164.
844.
Eur. J. Inorg. Chem. 2007, 3553–3560
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
3559

A. García, E. Lalinde, M. T. Moreno
FULL PAPER
[50]
[72] W. Lu, M. C. W. Chan, N. Zhu, C. M. Che, Z. He, K. Y. Wong,
Chem. Eur. J. 2003, 9, 6155–6166.
[73] M. Janka, G. K. Anderson, N. P. Rath, Organometallics 2004,
23, 4382–4390.
[74] W. Lu, B. X. Mi, M. C. W. Chan, Z. Hui, C. M. Che, N. Zhu,
S. T. Lee, J. Am. Chem. Soc. 2004, 126, 4958–4971.
[75] M. I. Bruce, J. Davy, B. C. Hall, Y. J. van Galen, B. W. Skelton,
A. H. White, Appl. Organomet. Chem. 2002, 16, 559–568.
[76] C. H. Tao, K. M. C. Wong, N. Zhu, V. W. W. Yam, New J.
Chem. 2003, 27, 150–154.
[77] J. Vicente, M. T. Chicote, M. M. Álvarez-Falcón, P. G. Jones,
Organometallics 2005, 24, 2764–2772.
[78] M. S. Khan, M. R. A. Al-Mandhary, M. K. Al-Suti, F. R. Al-
Battashi, S. Al-Saadi, B. Ahrens, J. K. Bjernemose, M. F. Ma-
hon, P. R. Raithby, M. Younus, N. Chawdhury, A. Köhler,
E. A. Marseglia, E. Tedesco, N. Feeder, S. J. Teate, Dalton
Trans. 2004, 2377–2385.
[79] J. R. Berenguer, J. Forniés, E. Lalinde, F. Martínez, E. Urriola-
beitia, A. J. Welch, J. Chem. Soc. Dalton Trans. 1994, 1291–
1299.
[80] I. Ara, J. R. Berenguer, J. Forniés, E. Lalinde, M. Tomás, Orga-
nometallics 1996, 15, 1014–1022.
C. J. Adams, M. I. Bruce, E. Horn, B. W. Skelton, E. R. T. Tie-
kink, A. H. White, J. Chem. Soc. Dalton Trans. 1993, 3299–
3312.
C. J. Adams, M. I. Bruce, E. Horn, B. W. Skelton, E. R. T. Tie-
kink, A. H. White, J. Chem. Soc. Dalton Trans. 1993, 3313–
3322.
D. Xu, B. Hong, Angew. Chem. Int. Ed. 2000, 39, 1826–1829.
P. Blenkiron, N. J. Taylor, A. J. Carty, J. Chem. Soc. Chem.
Commun. 1995, 327–328.
[51]
[52]
[53]
[54]
[55]
P. Blenkiron, J. F. Corrigan, D. Pilette, N. J. Taylor, A. J. Carty,
Can. J. Chem. 1996, 74, 2349–2362.
P. Blenkiron, G. D. Enright, P. J. Low, J. F. Corrigan, N. J. Tay-
lor, Y. Chi, J. Y. Saillard, A. J. Carty, Organometallics 1998, 17,
2447–2458.
R. J. Cross, M. F. Davidson, J. Chem. Soc. Dalton Trans. 1986,
1987–1992.
J. Forniés, M. A. Gómez-Saso, E. Lalinde, F. Martínez, M. T.
Moreno, Organometallics 1992, 11, 2873–2883.
P. S. Pregosin, R. W. Kunz, in NMR Basic Principles and Pro-
gress (Eds: P. Diehl, E. Fluck, R. Kosfeld), Springer-Verlay,
New York, 1979, vol. 16, pp. 43–45.
[56]
[57]
[58]
[81] L. R. Falvello, J. Forniés, R. Navarro, A. Rueda, E. Urriolabei-
tia, Organometallics 1996, 15, 309–316.
[82] I. Ara, J. R. Berenguer, E. Eguizábal, J. Forniés, E. Lalinde, A.
Martín, F. Martínez, Organometallics 1998, 17, 4578–4596.
[83] I. Ara, J. R. Berenguer, E. Eguizábal, J. Forniés, E. Lalinde,
Organometallics 2001, 20, 2686–2696.
[59]
[60]
E. Louattani, A. Lledós, J. Suades, A. Alvarez-Larena, J. F.
Piniella, Organometallics 1995, 14, 1053–1060.
E. Louattani, J. Suades, Inorg. Chim. Acta 1999, 291, 207–211.
[61] A. Díez, J. Forniés, A. García, E. Lalinde, M. T. Moreno, In-
org. Chem. 2005, 44, 2443–2453.
[62] A. García, J. Gómez, E. Lalinde, M. T. Moreno, Organometal-
lics 2006, 25, 3926–3934.
[63] J. Manna, K. D. John, M. D. Hopkins, Adv. Organomet. Chem.
1995, 38, 79–154.
[84] J. R. Berenguer, E. Eguizábal, L. R. Falvello, J. Forniés, E. Lal-
inde, A. Martín, Organometallics 2000, 19, 490–496.
[85] J. R. Berenguer, L. R. Falvello, J. Forniés, E. Lalinde, M.
Tomás, Organometallics 1993, 12, 6–7.
[64] R. Saha, M. D. Qaium, D. Debnath, M. Younus, N.
Chawdhury, N. Sultana, G. Kociok-Köhn, L. Ooi, P. R.
Raithby, M. Kijima, Dalton Trans. 2005, 2760–2765.
[65] M. S. Khan, M. R. A. Al-Mandhary, M. K. Al-Suti, B. Ahrens,
M. F. Mahon, L. Male, P. R. Raithby, C. E. Boothby, A.
Köhler, Dalton Trans. 2003, 74–84.
[66] C. J. Adams, S. L. James, X. Liu, P. R. Raithby, L. J. Yellowlees,
J. Chem. Soc. Dalton Trans. 2000, 63–67.
[67] S. M. Al Qaisi, K. J. Galat, M. Chai, D. G. Ray III, P. L. Rin-
aldi, C. A. Tessier, W. J. Youngs, J. Am. Chem. Soc. 1998, 120,
12149–12150.
[68] M. I. Bruce, K. Costuas, J. F. Halet, B. C. Hall, P. J. Low, B. K.
Nicholson, B. W. Skelton, A. J. White, J. Chem. Soc. Dalton
Trans. 2002, 383–398.
[69] V. W. W. Yam, K. M. C. Wong, N. Zhu, J. Am. Chem. Soc.
2002, 124, 6506–6507.
[70] T. B. Peters, Q. Zheng, J. Stahl, J. C. Bohling, A. M. Arif, F.
Hampel, J. A. Gladysz, J. Organomet. Chem. 2002, 641, 53–61.
[71] W. Lu, B. X. Mi, M. C. W. Chan, Z. Hui, N. Zhu, S. T. Lee,
C. M. Che, Chem. Commun. 2002, 206–207.
[86] O. Lavastre, S. Cabioch, P. H. Dixneuf, J. Vohlidal, Tetrahedron
1997, 53, 7595–7604.
[87] E. Louattani, J. Suades, R. Mathieu, J. Organomet. Chem.
1991, 421, 335–340.
[88] R. Usón, J. Forniés, M. Tomás, B. Menjón, Organometallics
1985, 4, 1912–1914.
[89] Z. Otwinowski, W. Minor, in Methods in Enzymology (Eds:
C. V. Carter Jr, R. M. Sweet), Academic Press, New York,
1997, vol. 276A, pp. 307.
[90] R. H. Blessing, Acta Crystallogr., Sect. A 1995, 51, 33–38.
[91] P. T. Beursken, G. Beursken, W. P. Bosman, R. de Gelder, S.
García-Granda, R. O. Gould, J. M. M. Smith, C. Smykalla,
The DIRDIF92 program system, Technical Report of the Crys-
tallography Laboratory, University of Nijmegen, The Nether-
lands, 1992.
[92] G. M. Sheldrick, SHELX-97, Program for Crystal Structure
Determination from Diffraction Data, University of Göttingen,
Germany, 1997.
Received: January 30, 2007
Published Online: June 18, 2007
3560
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© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2007, 3553–3560