Gold compounds anchored to a metalated arene scaffold: Synthesis, X-ray molecular structures, and cycloisomerization of enyne

Article abstract of DOI:10.1021/om301101z

A novel series of π-complexes of phosphino ligands, [Cp*Ru(η ⁶-arene-PAr₂)][OTf], has been prepared in which the diarylphosphine unit is attached to a metalated π-arene scaffold. These organometallic phosphino ligands display either an electron-donating methyl group (-PAr₂ = -P(p-tol)₂) or electron-withdrawing trifluoromethyl group (-PAr₂ = -P(p-C₆H₄CF ₃)₂). This unique class of metallo ligands was converted to heterodinuclear gold complexes upon treatment with [AuCl(tht)]. The molecular structures of [Cp*Ru(η⁶-p-CH₃C ₆H₄-P(p-tol)₂-Au-Cl)][OTf] and [Cp*Ru(η⁶-C₆H₅-P(p-C ₆H₄CF₃)₂)-Au-Cl][OTf] were ascertained by single-crystal X-ray diffraction. A comparative study of these structures with that of [Cp*Ru(η⁶-C₆H ₅-PPh₂-Au-Cl)][OTf] previously reported revealed important information about the electronic nature of the gold center when it is bonded to a -PPh₂, -P(p-tol)₂, or -P(p-C₆H ₄CF₃)₂ metallo ligand. DFT computations also shed light on the effect of [Cp*Ru⁺] coordination to [AuCl(PAr₃)] precatalysts. Several complexes of the family with electron-donating and -withdrawing groups were evaluated toward cycloisomerization reactions of a classical N-tethered 1,6-enyne. These results are presented and discussed.

Full text of DOI:10.1021/om301101z

Article
pubs.acs.org/Organometallics
Gold Compounds Anchored to a Metalated Arene Scaffold:
Synthesis, X‑ray Molecular Structures, and Cycloisomerization of
Enyne
Julien Dubarle-Offner, Marion Barbazanges, Mylene Auge, Christophe Desmarets, Jamal Moussa,
̀
́
M. Rosa Axet, Cyril Ollivier, Corinne Aubert,* Louis Fensterbank, Vincent Gandon,† Max Malacria,
Geoffrey Gontard, and Hani Amouri*
UPMC Universite
05, France
́ ́
Paris 06, Institut Parisien de Chimie Moleculaire (UMR CNRS 7201), 4 place Jussieu, C. 42, 75252 Paris Cedex
S
* Supporting Information
ABSTRACT: A novel series of π-complexes of phosphino
ligands, [Cp*Ru(η6-arene-PAr2)][OTf], has been prepared in
which the diarylphosphine unit is attached to a metalated π-
arene scaffold. These organometallic phosphino ligands display
either an electron-donating methyl group (−PAr2 = −P(p-
tol)2) or electron-withdrawing trifluoromethyl group (−PAr2 =
−P(p-C6H4CF3)2). This unique class of metallo ligands was
converted to heterodinuclear gold complexes upon treatment with [AuCl(tht)]. The molecular structures of [Cp*Ru(η6-p-
CH3C6H4-P(p-tol)2-Au-Cl)][OTf] and [Cp*Ru(η6-C6H5-P(p-C6H4CF3)2)-Au-Cl][OTf] were ascertained by single-crystal X-ray
diffraction. A comparative study of these structures with that of [Cp*Ru(η6-C6H5-PPh2-Au-Cl)][OTf] previously reported
revealed important information about the electronic nature of the gold center when it is bonded to a −PPh2, −P(p-tol)2, or
−P(p-C6H4CF3)2 metallo ligand. DFT computations also shed light on the effect of [Cp*Ru+] coordination to [AuCl(PAr3)]
precatalysts. Several complexes of the family with electron-donating and -withdrawing groups were evaluated toward
cycloisomerization reactions of a classical N-tethered 1,6-enyne. These results are presented and discussed.
moieties displaying electron-donating and -withdrawing groups
(vide infra).
INTRODUCTION
■
There is a resurgence of interest in designing metallo ligands
for applications in various fields of chemistry.1 Particularly
attractive is the use of phosphine−ferrocene-based metallo
ligands to synthesize active catalysts which have proven to be
effective in promoting high activity and enantioselectivity in a
range of metal-mediated asymmetric transformations.2 In the
latter, it is believed that metallo ligands would influence both
the electronic and steric properties of the active metal site.
However, the development of alternative, structurally diverse
metallo ligands to the well-known ferrocenyl-based compounds
has received little attention.3 Some of us have developed the
synthesis of several neutral metalated π-quinones, thioquinones,
and selenoquinones stabilized by “Cp*M” fragments (M = Rh,
Ir).4 These π-quinonoid species were successfully used as
metallo ligands to prepare a variety of coordination assemblies
and polymers with luminescent properties.5 More recently we
described the synthesis of the heterodinuclear complex LM→
Au-Cl, where a gold center is attached to a phosphino metallo
ligand LM of formula κ1-PPh2-[Cp*Ru(η6-benzene)][OTf]
(2a′-OTf) (Scheme 1). The subsequent heterobimetallic
complex [Cp*Ru(η6-C6H5-PPh2-Au-Cl)][OTf] (3a′-OTf) was
found to be active in metal-catalyzed cycloisomerization
reactions and especially toward β-hydroxyallenynes.6 Thus, we
decided to extend the scope of this class of metalated
phosphino ligands LM by introducing new diarylphosphine
Homogeneous gold catalysis has emerged as a powerful tool
for organic transformations, thus providing a variety of bond-
forming reactions for the synthesis of complex chemical
structures.7 In this context, efforts have been devoted to
prepare new gold complexes by tuning the electronic and/or
the steric properties of the donor ligand bound to the metal
center “L→Au” (L= PR3, carbenes, cyclic and acyclic
aminocarbenes, carbodiphosphoranes, etc.).8
We sought to change the electronic and steric properties
around the gold center in hopes that this might lead to new
reactive species. In this paper we extended our approach to
other diarylphosphino π-complexes LM displaying electron-
donating and -withdrawing groups, which allowed us to obtain
a series of heterodinuclear Ru−Au compounds. The molecular
structures of two such compounds (3b-OTf and 5-OTf) are
reported and compared to that of a parent complex previously
described (3a′-OTf).6 The X-ray data provided us with valuable
information about the electronic properties of the gold center
within the binuclear species. The steric and electronic
influences of [Cp*Ru+] coordination to [AuCl(PAr3)] have
been investigated by DFT computations. Furthermore, this
Received: November 15, 2012
© XXXX American Chemical Society
A
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Scheme 1. Previous Work: Preparation of the Phosphino Ligand 2a′-OTf and the related heterobimetallic precatalyst 3a′-OTf
Scheme 2. Preparation of a New Set of Heterodinuclear Ru−Au Complexes [Cp*Ru(η6-arene-P(p-tol)2)-Au-Cl][OTf] (3a−e-
OTf)
Scheme 3. Preparation of a Heterodinuclear Gold Complex with Electron-Withdrawing Trifluoromethyl Groups in the Para
Position (5-OTf)
family of ligands was evaluated toward the same 1,6-enyne
cycloisomerization reaction in order to probe the role of the
metalated phosphino ligands on the activity of the gold center
and to establish a structure−reactivity relationship.
well-known that a small change in the nature of the phosphine
ligands has an important impact on the solubility and reactivity
of the target catalyst precursors. Unfortunately, all attempts to
prepare the organometallic phosphine ligands with alkyl groups
−PR2 (R = −Cy, −Et, −Me) were unsuccessful. However, with
tolyl groups, they were successfully introduced following the
method reported by Gladysz and co-workers for the formation
of LiP(p-tol)2.10
RESULTS AND DISCUSSION
■
Synthesis and Characterization of a Novel Family of
π-Complexed Phosphino Ligands, [Cp*Ru(η6-arene-
PAr2)][OTf] (2a−e-OTf), and the Related Gold Complexes
[Cp*Ru(η6-arene-PAr2)-Au-Cl][OTf] (3a−e-OTf). The syn-
thesis of the organometallic phosphino ligand 2a′-OTf was
performed as described previously6 in two steps starting from
the ruthenium precursor [Cp*Ru(CH3CN)3][OTf]9 and using
the commercially available KPPh2. In addition, we had also
reported that treatment of the organometallic phosphino ligand
2a′-OTf with 1 equiv of [AuCl(tht)] (tht = tetrahydrothio-
phene) in dichloromethane provided the target gold compound
3a′-OTf in high yield (Scheme 1).6
Thus, the novel series of complexes [Cp*Ru(η6-arene-P(p-
tol)2)][OTf] (2a-e-OTf) were prepared by treatment of the
appropriate haloaromatic metal complex [Cp*Ru(η6-arene-
Cl)][OTf] (1a-e-OTf) with LiP(p-tol)2 prepared in situ by
addition of 1 equiv of a n-BuLi solution in n-hexanes to a HP(p-
tol)2 solution in n-hexanes (Scheme 2). All phosphine ligands
of this series were isolated as white microcrystalline solids after
reaction workup and were fully characterized by NMR
spectroscopy and microanalytical data (see the Experimental
1
Section). For instance, the H NMR spectrum of [Cp*Ru(η6-
C6H5-P(p-tol)2)][OTf] (2a-OTf) recorded in CD2Cl2 shows a
singlet at δ 2.00 ppm attributed to the methyl protons of the
Cp* and also a singlet at δ 2.40 ppm assigned to the methyl
protons of the p-tolyl groups while three multiplets are visible
We sought to prepare a variety of metalated phosphino
ligands displaying electron-donating and -withdrawing groups
in comparison to the previously reported ligand 2a′-OTf. It is
B
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Figure 1. Molecular structures of the cationic heterodinuclear complexes (left) [Cp*Ru(η6-p-MeC6H4-P(p-tol)2)-Au-Cl]+ (3b) and (right)
[Cp*Ru(η6-C6H5-P(p-C6H4CF3)2)-Au-Cl]+ (5) with the atom-numbering system. Complex 3b shows dimer formation as a result of an Au1- - -Au2
interaction at 3.0809(4) Å. Hydrogen atoms are omitted for clarity.
Figure 2. Molecular structures of cationic heterodinuclear complexes (left) 3a′, (middle) 3b (Au- - -Au interaction not shown), and (right) 5 with
atom-numbering system exhibiting similar features (i.e. the AuCl moiety leans toward the “Cp*Ru” moiety due to the orientation of the diaryl
phosphine groups). Hydrogen atoms are omitted for clarity.
at δ 5.45, 5.78, and 5.88 ppm, attributed to the protons of the
η6-aromatic ring. We also note the presence of a set of
multiplets in the range δ 7.28−7.36 ppm attributed to the
aromatic protons of the −P(p-tol)2 moiety. Furthermore, the
31P NMR spectrum recorded in CD2Cl2 showed a singlet at δ
−16.8 ppm. Gratifyingly, after many attempts we were able to
prepare a novel metalated phosphino ligand [Cp*Ru(η6-C6H5-
P(p-C6H4CF3)2][OTf] (4) with an electron-withdrawing group
(−p-C6H4CF3) bound to the phosphorus atom following a
different synthetic procedure (Scheme 3).11 Having obtained
the organometallic phosphine ligands with different electron-
donating and -withdrawing groups, we carried out the
preparation of the related gold complexes (vide infra).
32.5 ppm. The downfield shift of the signal is significative of the
coordination of the gold center by the organometallic
phosphine ligand. The related heterodinuclear gold complexes
[Cp*Ru(η6-arene-P(p-tol)2)-Au-Cl][OTf] (3b−e-OTf) and
[Cp*Ru(η6-C6H5-P(p-C6H4CF3)2)-Au-Cl][OTf] (5-OTf)
were also obtained as pale white solids and were fully
characterized by NMR spectroscopy and elemental analysis
(see the Experimental Section). In addition, the X-ray
molecular structures of [Cp*Ru(η6-p-MeC6H4-P(p-tol)2)-Au-
Cl][OTf] (3b-OTf) and [Cp*Ru(η6-C6H5-P(p-C6H4CF3)2)-
Au-Cl][OTf] (5-OTf) were determined and compared to that
of [Cp*Ru(η6-C6H5-PPh2)-Au-Cl][OTf] (3a′-OTf) described
previously (vide infra).6
To attain the target gold compound 3a-OTf, we treated the
organometallic phosphino ligand 2a-OTf with 1 equiv of
[AuCl(tht)] in dichloromethane. The reaction proceeded
smoothly under argon and was left for 1 h. Reaction workup
provided a white crystalline solid in 90% yield (Scheme 2).
Elemental analysis and spectroscopic data suggested the
formation of [Cp*Ru(η6-C6H5-P(p-tol)2)-Au-Cl][OTf] (3a-
Molecular Structures of [Cp*Ru(η6-C6H5-PPh2)-Au-Cl]-
[OTf] (3a′-OTf), [Cp*Ru(η6-p-MeC6H4-P(p-tol)2)-Au-Cl]-
[OTf] (3b-OTf), and [Cp*Ru(η6-C6H5P(p-C6H4CF3)2)-Au-
Cl][OTf] (5-OTf). Convenient crystals for X-ray study of the
heterodinuclear Ru−Au complexes 3b-OTf and 5-OTf were
obtained at room temperature by vapor diffusion of diethyl
ether into a dichloromethane solution. Crystal data are given in
Table S1 (Supporting Information). The X-ray structure of 3b-
OTf revealed the presence of two independent heterobimetallic
molecules a and b, which exhibit an Au- - -Au interaction
1
OTf). The H NMR recorded in CD2Cl2 is in agreement with
the proposed formula and showed signals downfield relative to
the phosphine ligand 2a-OTf. The 31P NMR spectrum in
CD2Cl2 was the most informative and showed a singlet at δ
C
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Table 1. Comparative Bond Lengths (Å) and Angles (deg) for Complexes 3a′-OTf, 3b-OTf, 5-OTf, and [AuCl(PPh3)]
3a′-OTf
3b-OTf
5-OTf
[AuCl(PPh3)]
Au1−P1
2.218(1)
2.270(1)
Au1−P1
Au2−P2
Au1−Cl1
Au2−Cl2
Ru1−C1
Ru1−C2
Ru1−C3
Ru1−C4
Ru1−C5
Ru1−C6
P1−C1
2.230(1)
2.230(2)
2.281(2)
2.287(2)
2.230(6)
2.198(6)
2.208(6)
2.234(6)
2.215(6)
2.204(5)
1.803(6)
1.795(6)
1.818(5)
171.65(6)
103.7(3)
107.8(3)
105.9(3)
108.08(18)
115.5(2)
114.99(17)
Au1−P1
Au2−P2
2.220(2)
2.221(2)
2.271(2)
2.277(2)
2.240(5)
2.226(6)
2.200(6)
2.196(6)
2.204(6)
2.213(5)
1.825(5)
1.823(6)
1.821(5)
178.19(6)
105.5(2)
106.7(2)
105.0(3)
112.24(19)
113.01(19)
113.67(18)
Au−P
2.235(3)
Au1−Cl1
Au1−Cl1
Au2−Cl2
Ru1−C1
Ru1−C2
Ru1−C3
Ru1−C4
Ru1−C5
Ru1−C6
P1−C1
Au−Cl
2.279(3)
Ru1−C1
Ru1−C2
Ru1−C3
Ru1−C4
Ru1−C5
Ru1−C6
P1−C1
2.217(3)
2.205(3)
2.209(3)
2.212(3)
2.197(3)
2.200(3)
1.817(3)
P−C1
P−C7
P−C13
P−Au−Cl
C1−P−C7
C1−P−C13
C7−P−C13
C1−P−Au
C7−P−Au
C13−P−Au
1.803(13)
1.866(12)
1.792(13)
179.63(8)
103.3(4)
106.2(5)
105.8(4)
114.8(5)
113.3(5)
112.5(5)
P1−C17
P1−C23
1.819(3)
P1−C18
P1−C25
P1−C17
P1−C24
1.815(4)
P1−Au1−Cl1
C1−P1−C17
C23−P1−C1
C23−P1−C17
C1−P1−Au1
C17−P1−Au1
C23−P1−Au1
176.34(4)
108.70(14)
102.60(15)
103.79(13)
111.84(10)
112.29(11)
116.80(10)
P1−Au1−Cl1
C1−P1−C25
C18−P1−C1
C18−P1−C25
C1−P1−Au1
C18−P1−Au1
C25−P1−Au1
P1−Au1−Cl1
C1−P1−C24
C17−P1−C1
C17−P1−C24
C1−P1−Au1
C17−P1−Au1
C24−P1−Au1
Table 2. 31P NMR Data (δ in ppm and J in Hz) for PPh3 and
Metalated Phosphino Ligands (P(III)) and the Selenide
Derivatives (P(V)) in CD2Cl2
(3.0809(4) Å), resulting in the formation of a dimeric
compound (Figure 1).12
For comparison purposes, the molecular structures of 3b, 5,
and 3a′ are depicted in Figure 2 and comparative bond
distances and angles are given in Table 1. We notice that the
“Cp*Ru” moiety is symmetrically coordinated to the η6-phenyl
group. The structures of 3b and 5 exhibited features similar to
that of 3a′; we note for instance that the AuCl molecular brick
leans in the same fashion toward the “Cp*Ru” unit. The solid-
state structures of 3a′, 3b, and 5 showed marked differences
from the known complex [AuCl(PPh3)] (Figure 2).13 At first
glance and in contrast to [AuCl(PPh3)], the two sides of the
cationic gold complexes are no longer equivalent, at least in the
solid state. Indeed, one face of this complex is closer to the
“Cp*Ru”, which would hinder the approach of the substrate
while the other side is open; thus, one might expect a different
reactivity in comparison to the parent compound [AuCl-
(PPh3)]. Furthermore, the sum of three C−P−C angles (θ) for
3b was found to be 317.60°, on average, comparable to that for
5 (317.28°) but slightly larger than those for 3a′ (315.20°) and
[AuCl(PPh3)] (315.16°).2b We then evaluated the electronic
properties of these organometallic ligands.14
The electronic properties of these metalated phosphines 2a′,
2a−d, and 4 were evaluated by converting the metalated
phosphino ligands to the related selenide complexes [Cp*Ru-
(η6-arene-PAr2)Se][OTf]. Subsequent measurement of
1JP−Se coupling constants allowed us to classify the donor
capacity of these compounds as follows: 2c > 2d > 2b > 2a >
2a′ > 4. It is worth mentioning that electron-withdrawing
groups on phosphorus cause the coupling constant to increase,
while electron-donating groups provide a smaller coupling
constant value (Table 2).15
selenide derivative
phosphino ligand
δ(P(III))
δ(P(V))
1JP−Se
[Cp*Ru(η6-C6H5-PPh2)]+ (2a′)
−13.3
−16.8
35.9 (2a′Se)
35.0 (2aSe)
775
772
[Cp*Ru(η6-C6H5-P(p-tol)2)]+
(2a)
[Cp*Ru(η6-p-MeC6H4-P(p-
−17.3
−16.9
−22.4
−14.9
−7.9
33.7 (2bSe)
33.3 (2cSe)
31.2 (2dSe)
36.7 (4Se)
771
768
769
796
724
tol)2)]+ (2b)
[Cp*Ru(η6-p-MeOC6H4-P(p-
tol)2)]+ (2c)
[Cp*Ru(η6-o-MeC6H4-P(p-
tol)2)]+ (2d)
[Cp*Ru(η6-C6H5-P(p-
C6H4CF3)2)]+ (4)
PPh3
35.9 (Ph3PSe)
decrease of d3, and the increase of d4. This prediction is
perfectly followed when P(p-tol)3 is compared with [Cp*Ru-
(η6-p-MeC6H4-P(p-tol)2)] (2b). Inspection of the natural
charge distributions shows that the charge on gold virtually
does not change with the coordination of the “Cp*Ru” unit on
the phosphine. On the other hand, the charge on the phosphine
decreases upon complexation of ruthenium, as a result of
charge transfer to the allyl framework. Thus, the introduction of
“Cp*Ru” enhances the electrophilicity of the substrate.
The increase of the d1 value also suggests that the steric
demand around the Au−P bond increases significantly upon
complexation of “Cp*Ru”. To gain more insight into this issue,
we looked at the percent buried volume18 for 2a′, 2b, and 4
using the X-ray structures of 3a′, 3b, and 5 (Table 4). Clearly,
the complexation of “Cp*Ru” to PPh3 results in a more
crowded environment around gold, the %Vbur value increasing
from 34.8 to 42.9 (entries 1 and 2). The same is true for P(p-
tol)3 and the corresponding metalated phosphine (entries 3 and
4). In fact, the values for phosphines 2a′, 2b, and 4 are
comparable with those of P(t-Bu)3 or P(o-tol)3, which are the
most sterically demanding phosphines after P(Mes)3 (entries
We reasoned that the “Cp*Ru” moiety should increase the π-
acidity of the phosphines. This hypothesis was first verified by
DFT computations16 using the “allyl model” reported by Toste
et al. (Table 3).17 Enhancing the π-acidity decreases the back-
donation to the allyl ligand. As a result, the Au−C bond order
decreases. The geometrical sequel is the increase of d2, the
D
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Table 3. Geometrical Features and Natural Charges of Gold Complexes Optimized by M06 Computations
catalyst 3b-OTf, not only was the stability improved but also
the reactivity increased and a positive platform effect was
observed (Figure 3-2, blue curve). Indeed, after 75 min, the
conversion reached 98% with 3b-OTf vs 84% for its
mononuclear counterpart [AuCl(P(p-tol)3)], and the hetero-
cyclic product 7 was isolated in 92% vs 73% yield, respectively.
We then investigated the influence of the substituent at the
arene platform. As indicated by the JSe−P NMR constants
(Table 2), 2a−e-OTf ligands possess comparable π-acidic
properties within the family; therefore, a similar behavior in
catalysis was expected. Indeed, when the [Cp*Ru(η6-p-
MeOC6H4-P(p-tol)2)-Au-Cl] catalyst 3c-OTf was used, an
equivalent reactivity was observed (Figure 4, black curve). A
similar result was observed with the [Cp*Ru(η6-C6H5-P(p-
tol)2)-Au-Cl][OTf] catalyst 3a-OTf, bearing no substituent at
the platform (Figure 4, red curve), thus underlying the scant
influence of the platform’s para substitution with respect to the
stability and the reactivity of the catalyst. However, the steric
properties should not be neglected, as highlighted by ortho-
substituted catalysts 3d-OTf and 3e-OTf, possessing the largest
%Vbur values of the tested series (Table 4). Moving the methyl
substituent from the para to the ortho position (3d-OTf)
indeed slowed down the reaction (green curve), and when an o-
methoxy group was introduced (3e-OTf), no conversion was
observed, presumably because of the degradation of the cationic
catalyst in solution (brown curve).
As a π-acidic bimetallic catalyst had better activity than its
homologous mononuclear phosphine gold compound, we then
tested [Cp*Ru(η6-C6H5-P(p-C6H4CF3)2)-Au-Cl][OTf] (5-
OTf), bearing two electron-withdrawing groups (p-C6H4CF3)
bound to the phosphorus atom. The latter should be more π-
acidic than the previous 3a−e-OTf family, with regard to the
Se−P coupling constant in 4Se (798 Hz vs 768−772 Hz for
2a−eSe phosphines; see Table 2). Treatment of enyne 6 by
5-OTf catalyst (5 mol %) in the presence of AgSbF6 (7 mol %)
(CH2Cl2, room temperature ) led indeed to the fastest reaction
and full conversion was obtained after 45 min (Figure 5, purple
curve).
Table 4. %Vbur Values of Some Ligands
%Vbur in L-Au-Cl for M−P length
at 2.00 Å
entry
L
a
1
2
3
4
P(Ph)3
34.8
b
c
[Cp*Ru(η6-C6H5-PPh2)]+ (2a′)
P(p-tol)3
42.9 (43.8)
a
34.2
b
c
[Cp*Ru(η6-p-MeC6H4-P(p-
43.1 (43.4)
tol)2)]+ (2b)
a
5
6
7
8
P(t-Bu)3
P(o-tol)3
P(Mes)3
43.9
a
44.8
a
50.5
c
[Cp*Ru(η6-C6H5-P(p-tol)2)]+
(2a)
(43.5)
c
9
[Cp*Ru(η6-o-MeC6H4-P(p-
(46.7)
tol)2)]+ (2d)
c
10
11
12
[Cp*Ru(η6-p-MeOC6H4-P(p-
tol)2)]+ (2c)
(44.2)
c
[Cp*Ru(η6-o-MeOC6H4-P(p-
(47.2)
tol)2)]+ (2e)
b
c
[Cp*Ru(η6-C6H5-P(p-
43.4 (44.6)
C6H4CF3)2)] (4)
a
b
Values obtained from ref 17. Values obtained from X-ray structures.
Values obtained from the calculated gold complexes of Table 3.
c
5−7). The rest of the %Vbur values were obtained from
calculated geometries, since the X-ray structures of the
corresponding gold chlorides are not available. Along the
series of metalated phosphines (entries 2, 4, and 8−12), the
largest %Vbur values are observed with ortho-substituted aryl
groups (entries 9 and 11).
Comparison of the Heterobimetallic Gold Com-
pounds 3a′-OTf, 3a−e-OTf, and 5-OTf in Catalysis. The
catalytic activity of the heterodinuclear gold complexes
[Cp*Ru(η6-arene-PAr2)-Au-Cl][OTf] was then tested in the
cycloisomerization reaction of N-tethered 1,6-enyne 6 and
compared to the commercially available homologous mono-
nuclear phosphine gold compounds [AuCl(PAr3)], in order to
probe any platform effect on the selectivity and/or the
reactivity (Figure 3).19,20 When 6 was submitted to [Cp*Ru-
(η6-C6H5-PPh2)-Au-Cl][OTf] (3a′-OTf; 5 mol %), in the
presence of AgSbF6 (7 mol %) in dichloromethane at room
temperature, the related bicyclic product 7 was cleanly and
selectively formed, but in a slower fashion than when
[AuCl(PPh3)] was used, with concomitant catalyst degradation
(Figure 3-1, yellow curve).21 After 75 min, 79% conversion (7/
(6 + 7) ratio) was observed for 3a′-OTf vs 84% for
[AuCl(PPh3)], and the corresponding bicycle 7 was isolated
in 67% and 76% yields, respectively. As 3a′-OTf was not stable
enough, we switched to [AuCl(P(p-Tol)3)] bimetallic ana-
logues. By using the [Cp*Ru(η6-p-MeC6H4-P(p-tol)2)-Au-Cl]
CONCLUDING REMARKS
■
In conclusion, we have reported a novel approach to prepare
metalated phosphino ligands [Cp*Ru(η6-arene-P(p-Ar)2)]+
(2a−e and 4) displaying electron-donating and -withdrawing
groups, which can be converted to the unique types of
heterobimetallic cationic gold complexes 3a′, 3a−e, and 5,
where the −PAr2-Au-Cl unit is now attached to the metalated
π-arene platform [Cp*Ru(η6-arene)][OTf]. The structures of
three compounds of this family were further ascertained by
E
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Figure 3. Comparison of 3a′-OTf (1) and 3b-OTf (2) with their homologous mononuclear triarylphosphine gold complexes, in the
cycloisomerization of N-tethered 1,6-enyne 6.
Figure 4. Influence of the platform substitution on the cycloisomerization of N-tethered 1,6-enyne 6.
catalyst in the presence of a silver salt. These results open the
way to the preparation of optically enriched binuclear catalysts,
displaying both planar chirality and high π-acidity, toward
enantioselective cycloisomerization reactions.26
EXPERIMENTAL SECTION
■
General Experimental Methods. 1H NMR spectra were
recorded at 300 or 400 MHz in CD2Cl2, and data are reported as
follows: chemical shift in ppm from tetramethylsilane with the solvent
as an internal indicator (CD2Cl2 δ 5.32 ppm), multiplicity (s = singlet,
d = doublet, t = triplet, q = quartet, m = multiplet or overlap of
nonequivalent resonances), integration. 13C NMR spectra were
recorded at 75 or 100 MHz in CD2Cl2, and data are reported as
follows: chemical shift in ppm from tetramethylsilane with the solvent
as an internal indicator (CD2Cl2 δ 54.0 ppm). 31P NMR spectra were
recorded at 121 MHz in CD2Cl2 with chemical shifts in ppm
referenced to H3PO4 as external standard. Glassware was oven-dried
prior to use. All reactions were carried out using Schlenk techniques
for the complex synthesis and under an argon atmosphere for the
catalysis. THF and diethyl ether were distilled from sodium−
benzophenone. CH2Cl2 was distilled from CaH2. Other reagents
were obtained from commercial suppliers and used as received. TLC
Figure 5. Influence of substitution of the aryls bound to the
phosphorus atom on the cycloisomerization of N-tethered 1,6-enyne 6.
single-crystal X-ray crystallography. The catalytic properties of
these heterodinuclear gold compounds were investigated
toward cycloisomerization of an N-tethered 1,6-enyne to give
selectively the related bicyclic product. In this reaction, the π-
acidic properties of our new metallo ligands were highly
interesting, notably in complex 5, which generates a powerful
F
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Article
measurements were performed on silica gel plates visualized either
with a UV lamp (254 nm). Flash chromatography was performed on
silica gel (230−400 mesh). Infrared spectra were measured using a
Tensor 27 (ATR diamond) Bruker spectrometer. IR data are reported
as characteristic bands (cm−1). The syntheses of 1a−e-OTf, 2a′-OTf,
and 3a′-OTf have already been reported in the literature.6,9
argon, and [AuCl(tht)] (156 mg, 0.49 mmol) was added to the
solution. The reaction mixture was stirred for 1 h at room temperature.
After that, the solution was passed through Celite. A white crystalline
solid was obtained after precipitation from CH2Cl2−diethyl ether.
Yield: 90%. 1H NMR (300 MHz, CD2Cl2): δ (ppm) 7.49 (m, H arene,
4H), 7.40 (m, H arene, 4H), 6.18 (m, H π-arene, 1H), 6.12 (m, H π-
arene, 2H), 6.00 (m, H π-arene, 2H), 2.46 (s, 2 p-Me, 6H), 2.04 (s,
Cp*, 15H). 13C NMR (100 MHz, CD2Cl2): δ (ppm) 134.2 (d, C2
arene, JC−P = 14.6 Hz), 133.1 (d, C4 arene, JC−P = 2.7 Hz), 129.5 (d,
C3 arene, JC−P = 12,3 Hz), 125.9 (d, C1 arene, JC−P = 62.5 Hz), 91.8
(d, C1 π-arene, JC−P = 53.0 Hz), 88.7 (d, C4 π-arene, JC−P = 1.1 Hz),
88.4 (d, C2 π-arene, JC−P = 13.2 Hz), 87.5 (d, C3 π-arene, JC−P = 7.4
Hz), 11.3 (s, 5 CH3, Cp*). 31P NMR (121 MHz, CD2Cl2): δ (ppm)
32.5. Anal. Calcd for C31H34AuClF3O3PRuS (908.12 g mol−1): C,
41.00; H, 3.77. Found: C, 41.08; H, 3.86.
Synthesis of [Cp*Ru(η6-C6H5-P(p-tol)2)][OTf] (2a-OTf). A
solution of LiP(p-tol)2 in hexanes (0.8 mL, 0.40 mmol) was prepared
in a Schlenk tube under argon by addition of nBuLi (1.6 M in hexanes)
to HP(p-tol)2 (10 wt % in hexanes) at room temperature, and the
mixture was stirred for 15 min. This yellow mixture was added at once
to a solution of compound 1a (200 mg, 0.40 mmol) dissolved in
tetrahydrofuran (20 mL) under argon, and the resulting orange
solution was stirred for 1 h. The solution was then evaporated to
dryness, dissolved in CH2Cl2, and passed through Celite to eliminate
the salt (LiCl) that formed during the reaction. Precipitation from
Synthesis of [Cp*Ru(η6-p-MeC6H4-P(p-tol)2)-Au-Cl][OTf] (3b-
OTf). 3b-OTf was prepared from the metalated phosphino ligand 2b-
1
CH2Cl2/diethyl ether gave a white solid. Yield: 77%. H NMR (300
1
OTf in a way similar to that described for 3a-OTf. Yield: 92%. H
MHz, CD2Cl2): δ (ppm) 7.36 (m, H arene, 4H), 7.28 (m, H arene,
4H), 5.88 (m, H π-arene, 1H), 5.78 (m, H π-arene, 2H), 5.45 (m, H π-
arene, 2H), 2.40 (s, 2Me, 6H), 2.00 (s, Cp*, 15H). 13C NMR (100
MHz, CD2Cl2): δ (ppm) 141.2, 134.5, 134.2, 130.1 (C arene), 98.1,
96.9, 88.3, 87.4, 87.0 (C π-arene), 21.0 (5 CH3, Cp*), 10.6, 10.1 (2
CH3, p-tol). 31P NMR (121 MHz, CD2Cl2): δ (ppm) −16.8. Anal.
Calcd for C31H34F3O3PRuS (675.70 g mol−1): C, 55.10; H, 5.07.
Found: C, 55.18; H, 5.15.
NMR (300 MHz, CD2Cl2): δ (ppm) 7.51 (m, H arene, 4H), 7.39 (m,
H arene, 4H), 6.00 (m, H π-arene, 4H), 2.47 (s, 2 p-CH3 arene, 6H),
2.37 (s, p-CH3 π-arene, 3H), 1.98 (s, Cp*, 15H). 13C NMR (75.4
MHz, CD2Cl2): δ (ppm) 135.4 (d, JC−P = 14.6 Hz, CH arene), 134.1
(CH arene), 130.6 (d, JC−P = 12.3 Hz, CH arene), 127.3 (d, JC−P
=
62.7 Hz, Cq arene), 103.8 (CH π-arene), 98.9 (Cq Cp*), 92.1 (d, JC−P
= 53.8 Hz, Cq π-arene), 89.6 (d, JC−P = 13.6 Hz, CH π-arene), 89.4 (d,
JC−P = 7.7 Hz, CH π-arene), 18.7 (p-CH3 π-arene) 11.7 (5 CH3, Cp*).
31P NMR (121 MHz, CD2Cl2): δ (ppm) 31.9. Anal. Calcd for
Synthesis of [Cp*Ru(η6-p-MeC6H4-P(p-tol)2)][OTf] (2b-OTf).
This compound was prepared in a way similar to that for 2a-OTf.
Yield: 87%. 1H NMR (300 MHz, CD2Cl2): δ (ppm) 7.37 (m, H arene,
4H), 7.28 (m, H arene, 4H), 5.63 (m, H π-arene, 2H), 5.42 (m, H π-
arene, 2H), 2.41 (s, 2p-CH3 arene, 6H), 2.25 (s, p-CH3 π-arene, 3H),
1.96 (s, Cp*, 15H). 13C NMR (100 MHz, CD2Cl2): δ (ppm) 141.2,
134.5, 134.2, 130.1 (C arene), 100.4, 96.2, 88.3, 88.1, 87.8 (C π-arene),
21.0 (5 CH3, Cp*), 17.9, 10.6, 10.1 (3 CH3, p-tol). 31P NMR (121
MHz, CD2Cl2): δ (ppm) −17.3. Anal. Calcd for C32H36F3O3PRuS
(689.73 g mol−1): C, 55.72, H 5.26. Found: C, 55.80; H, 5.32.
Synthesis of [Cp*Ru(η6-p-MeOC6H4-P(p-tol)2)][OTf] (2c-OTf).
This complex was prepared in a fashion similar to that for 2a-OTf.
Yield: 62%. 1H NMR (300 MHz, CD2Cl2): δ (ppm) 7.36 (m, H arene,
4H), 7.28 (m, H arene, 4H), 5.81 (m, H π-arene, 2H), 5.38 (m, H π-
arene, 2H), 3.86 (s, p-OCH3 π-arene, 3H), 2.40 (s, 2 p-CH3 arene,
6H), 1.97 (s, Cp*, 15H). 13C NMR (100 MHz, CD2Cl2): δ (ppm)
141.0, 134.4, 134.1, 130.0 (C arene), 97.2, 96.1, 87.2, 87.1, 75.7 (C π-
arene), 57.5 (p-OCH3), 21.0 (5 CH3, Cp*), 10.4, 10.3 (2 CH3, p-tol).
31P NMR (121 MHz, CD2Cl2): δ (ppm) −16.9. Anal. Calcd for
C32H36F3O4PRuS (705.73 g mol−1): C, 54.46; H, 5.14. Found: C,
54.58; H, 5.12.
C32H36AuClF3O3PRuS (922,15 g mol−1): C, 41.68; H, 3.93. Found: C,
41.60; H, 3.83.
Synthesis of [Cp*Ru(η6-p-MeOC6H4-P(p-tol)2)-Au-Cl][OTf]
(3c-OTf). 3c−OTf was prepared from the metalated phosphino
ligand 2c-OTf in a fashion similar to that described for 3a-OTf. Yield:
80%. 1H NMR (300 MHz, CD2Cl2): δ (ppm) 7.52 (m, H arene, 4H),
7.40 (m, H arene, 4H), 6.09 (m, H π-arene, 2H), 6.03 (m, H π-arene,
2H), 3.86 (s, OCH3, 3H), 2.46 (s, 2 Me, 6H) 1.97 (s, Cp*, 15H). 13
C
NMR (75.4 MHz, CD2Cl2): δ (ppm) 135.3 (d, JC−P = 14.6 Hz. CH
arene), 134.1 (CH arene), 130.6 (d, JC−P= 12.3 Hz, CH arene), 127.6
(d, JC−P = 62.7 Hz, Cq arene), 98.6 (Cq Cp*), 89.7 (d, JC−P = 54.8 Hz,
Cq arene), 88.9 (d, JC−P = 14.9 Hz, Cq arene), 87.8 (Cq π-arene), 77.1
(d, JC−P = 8.6 Hz, CH π-arene), 58.6 (p-OCH3 π-arene), 11.7 (5 CH3,
Cp*). 31P NMR (121 MHz, CD2Cl2): δ (ppm) 31.7. Anal. Calcd for
C32H36AuClF3O4PRuS (938.15 g mol−1): C, 40.97; H, 3.87. Found: C,
41.04; H, 3.85.
Synthesis of [Cp*Ru(η6-o-MeC6H4-P(p-tol)2)-Au-Cl][OTf] (3d-
OTf). 3d-OTf was prepared from the metalated phosphino ligand 2d-
1
OTf in a fashion similar to that described for 3a-OTf. Yield: 67%. H
Synthesis of [Cp*Ru(η6-o-MeC6H4-P(p-tol)2)][OTf] (2d-OTf).
This complex was prepared in a fashion similar to that for 2a-OTf.
Yield: 75%. 1H NMR (300 MHz, CD2Cl2): δ (ppm) 7.36 (m, H arene,
4H), 7.21 (m, H arene, 4H), 5.87 (m, H π-arene, 1H), 5.69 (m, H π-
arene, 2H), 5.13 (m, H π-arene, 1H), 2.42 (s, p-CH3 arene, 3H), 2.38
(s, p-CH3 arene, 3H), 2.00 (s, o-CH3 π-arene, 3H), 1.96 (s, Cp*,
15H). 13C NMR (100 MHz, CD2Cl2): δ (ppm) 141.4, 134.7, 134.0,
130.0 (C arene), 100.9, 96.5, 88.4, 88.1, 87.2 (C π-arene), 21.0 (5
CH3, Cp*), 17.2, 10.4, 10.1 (3 CH3, p-tol). 31P NMR (121 MHz,
CD2Cl2): δ (ppm) −22.4. Anal. Calcd for C32H36F3O3PRuS (689.73 g
mol−1): C, 55.72; H, 5.26. Found: C, 55.77; H, 5.34.
NMR (300 MHz, CD2Cl2): δ (ppm) 7.36−7.55 (m, H arene, 8H),
6.17 (m, H π-arene, 1H), 6.02 (m, H π-arene, 1H), 5.80 (m, H π-
arene, 1H), 5.21 (m, H π-arene, 1H), 2.49 (s, p-CH3 arene, 3H), 2.45
(s, p-CH3 arene, 3H), 2.38 (s, o-CH3 π-arene, 3H), 2.09 (s, Cp*,
15H). 13C NMR (75.4 MHz, CD2Cl2): δ (ppm) 145.5 (Cq arene),
136.2, 136.0, 135.1, 134.9, 131.9, 131.7 (8 CH arene), 99.2 (Cq π-
arene), 98.8 (Cq Cp*), 91.9, 90.4, 89.3, 87.6 (4 CH π-arene), 22.4 (o-
CH3 π-arene), 19.8 (p-CH3 arene), 19.7 (p-CH3 arene), 12.0 (5 CH3,
Cp*). 31P NMR (121 MHz, CD2Cl2): δ (ppm) 24.9. Anal. Calcd for
C32H36AuClF3O3PRuS (922,15 g mol−1): C, 41.68; H, 3.93. Found: C,
41.80; H, 3.90.
Synthesis of [Cp*Ru(η6-o-MeOC6H4-P(p-tol)2)-Au-Cl][OTf]
(3e-OTf). 3e-OTf was prepared from the metalated phosphino ligand
2e-OTf in a fashion similar to that described for 3a-OTf. Yield: 87%.
1H NMR (300 MHz, CD2Cl2): δ (ppm) 7.71 (d, J = 14.1 Hz, H arene,
Synthesis of [Cp*Ru(η6-o-MeOC6H4-P(p-tol)2)][OTf] (2e-OTf).
This complex was prepared in a fashion similar to that for 2a-OTf.
Yield: 74%. 1H NMR (300 MHz, CD2Cl2): δ (ppm) 7.42 (m, 10H, H
arene), 5.84 (m, 2H, J = 1.8 Hz, J = 5.9 Hz, H π-arene), 5.57 (dd, 2H, J
= 0.8 Hz, J = 5.9 Hz, H π-arene), 1.95 (s, Cp*, 15H), 1.76 (d, 6H, J =
0.8 Hz, o-CH3). 13C NMR (100 MHz, CD2Cl2): δ (ppm) 141.4, 135.7,
135.5, 130.1 (C arene), 97.8, 95.8, 88.0, 86.3, 74.2 (C π-arene), 57.2
(p-OCH3), 21.9 (5 CH3, Cp*), 10.5, 10.4 (2 CH3, p-tol). 31P NMR
2H), 7.69 (d, J = 14.1 Hz, H arene, 2H), 7.61 (m, H arene, 2H), 7.53
(m, H arene, 4H), 6.10 (dt, J = 2.4 Hz, J = 5.9 Hz, H π-arene, 1H),
5.81 (dd, J = 1.5 Hz, J = 5.9 Hz, H π-arene, 1H), 2.06 (s, Cp*, 15H),
1.89 (s, o-CH3 π-arene, 6H). 13C NMR (75.4 MHz, CD2Cl2): δ (ppm)
135.7 (d, JC−P = 14.6 Hz, CH arene), 134.1 (CH arene), 130.8 (d, JC−P
= 12,7 Hz, CH arene), 129.1 (d, JC−P = 62.4 Hz, Cq arene), 101.5 (d,
JC−P = 8.8 Hz, CH π-arene), 98.2 (Cq Cp*), 96.6 (d, JC−P = 47.1 Hz,
Cq arene), 91.7 (d, JC−P = 4.4 Hz, CH arene), 91.2 (CH π-arene), 22.4
(d, JC−P = 6.3 Hz, o-CH3 π-arene), 11.4 (5 CH3, Cp*). 31P NMR (121
(121 MHz, CD2Cl2):
δ (ppm) −12.0. Anal. Calcd for
C32H36F3O4PRuS (705.73 g mol−1): C, 54.46; H, 5.14. Found: C,
54.61; H, 5.21.
Synthesis of [Cp*Ru(η6-C6H5-P(p-tol)2)-Au-Cl][OTf] (3a-OTf).
2a-OTf (315 mg, 0.49 mmol) was dissolved in CH2Cl2 (30 mL) under
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MHz, CD2Cl2): δ (ppm) 30.42. Anal. Calcd for C32H36AuClF3O3PRuS
(938,15 g mol−1): C, 40.97; H, 3.54. Found: C, 41.10; H, 3.60.
Synthesis of [Cp*Ru(η6-C6H5-P(p-C6H4CF3)2)][OTf] (4-OTf).
HP(p-C6H4CF3)2 (250 mg, 0.77 mmol) was dissolved in tetrahy-
drofuran (2 mL) in a Schlenk tube under argon and then transferred at
−40 °C to another Schlenk tube containing a KH (46 mg, 1.5 equiv)
suspension in tetrahydrofuran (2 mL); this mixture was stirred under
argon for 2 h at −40 °C. This deep red solution was added at once to a
solution of compound 1a (250 mg, 0.50 mmol) dissolved in
tetrahydrofuran (20 mL) under argon; the resulting orange solution
was stirred for 11/2 h at −40 °C and then was warmed slowly to room
temperature. The solution was then evaporated to dryness, the residue
was dissolved in CH2Cl2, and this solution was passed through Celite.
Precipitation from CH2Cl2/diethyl ether gave a white solid. Yield:
33%. 1H NMR (300 MHz, CD2Cl2): δ (ppm) 7.76 (m, H arene, 4H),
7.61 (m, H arene, 4H), 6.05 (m, H π-arene, 1H), 5.96 (m, H π-arene,
2H), 5.51 (m, H π-arene, 2H), 2.03 (s, Cp*, 15H). 13C NMR (100
MHz, CD2Cl2): δ (ppm) 135.4, 135.2, (2 CF3), 126.7, 126.6, 126.6,
126.5 (12 C arene), 97.9, 88.5, 88.4, 88.3, 87.9, 87.8 (6 C π-arene),
11.1 (5 CH3, Cp*). 31P NMR (121 MHz, CD2Cl2): δ (ppm) −14.9.
19F NMR (120 MHz, CD2Cl2): δ (ppm) −63.5 (−C6H4CF3)2, −78.9
one portion. At a selected time, a sample (1 mL) was taken from the
reaction mixture and filtered through a short pad of silica (Et2O). After
concentration under reduced pressure and subsequent 1H NMR of the
crude material, the conversion (7/(6 + 7) ratio) was determined.
General Procedure for Isolated Yield. To a prestirred (10 min)
solution of the gold complex (0.005 mmol, 0.05 equiv) and AgSbF6
(2.4 mg, 0.007 mmol, 0.07 equiv) in CH2Cl2 (10 mL, c 0.01 M) at
room temperature was added 1,6-enyne 6 (32.5 mg, 0.1 mmol, 1
equiv) in one portion. After 75 min at room temperature, the reaction
mixture was filtered through a short plug of silica (Et2O) and then
concentrated under reduced pressure. Analysis of the crude material by
1H NMR indicated the conversion (7/(6 + 7) ratio). After purification
by flash chromatography (pentane/Et2O gradient: 95/5 to 90/10) an
inseparable mixture of bicyclic 7 and enyne 6 was isolated, as a white
solid. The spectral data are in agreement with those reported in the
literature.22
3a′-OTf: 27.7 mg, 79% conversion (crude), 67% corrected yield (7/
1
6 = 79/21, H NMR ratio).
[AuCl(PPh3)]: 29.6 mg, 84% conversion (crude), 76% corrected
1
yield (7/6 = 84/16, H NMR ratio).
3b-OTf: 30.4 mg, 98% conversion (crude), 92% corrected yield (7/
1
−
(SO3 CF3). Anal. Calcd for C31H28F9O3PRuS (783.65 g mol−1): C,
6 = 98/2, H NMR ratio).
[AuCl(P(p-tol)3)]: 28.5 mg, 80% conversion (crude), 73% corrected
47.51; H, 3.60. Found: C, 47.86; H, 3.68.
1
Synthesis of [Cp*Ru(η6-C6H5-P(p-C6H4CF3)2)-Au-Cl][OTf] (5-
OTf). 5-OTf was prepared from the metalated phosphino ligand 4-
yield (7/6 = 83/17, H NMR ratio).
X-ray Structural Determination of [Cp*Ru(η6-p-MeC6H4-P-p-
tol2)-Au-Cl][OTf] (3b-OTf) and [Cp*Ru(η6-C6H5-P(p-C6H4CF3)2)-
Au-Cl][OTf] (5-OTf). Data were collected on a Bruker Kappa-APEXII
instrument. Unit cell parameter determinations, data collection
strategies, and integration were carried out with the Bruker APEX2
suite of programs. A multiscan absorption correction was
applied.23The structures were solved by direct methods using
SIR9224 and SHELXS-86,25 respectively, and refined anisotropically
by full-matrix least-squares methods using SHELXL-97.25
1
OTf in a way similar to that described for 3a-OTf. Yield: 71%. H
NMR (400 MHz, CD2Cl2): δ (ppm) 7.87 (m, H arene, 4H), 7.81 (m,
H arene, 4H), 6.17 (m, H π-arene, 5H), 2.00 (s, Cp*, 15H). 13C NMR
(100 MHz, CD2Cl2): δ (ppm) 135.8, 135.6, 130.1, 127.4, 127.3, 127.2
(12 C arene), 99.7, 89.5, 89.4, 89.2, 88.6, 88.5 (6 C π-arene), 11.6 (s, 5
CH3, Cp*). 31P NMR (161 MHz, CD2Cl2): δ (ppm) 34.5. 19F NMR
(120 MHz, CD2Cl2): δ (ppm) −63.8 (−C6H4CF3)2, −78.8
−
(SO3 CF3). Anal. Calcd for C31H28AuClF9O3PRuS.CH2Cl2 (1099.93
g mol−1): C, 34.91; H, 2.75. Found: C, 34.54; H, 2.52.
ASSOCIATED CONTENT
* Supporting Information
General Procedure for the Preparation of the Selenide
Phosphino Ligands. The phosphine selenide derivatives were
prepared according to a published procedure.15b Degassed methanol
solutions (5 mL) containing KSeCN (3.2 mg, 0.022 mmol) and the
desired phosphino ligand (0.020 mmol) were prepared and stirred at
room temperature under argon for 30 min. The solutions were
evaporated to dryness, the solid residues were extracted with
dichloromethane, and the extracts were filtered through Celite. The
reactions were quantitative and provided stable white powders, as
■
S
Table S1 and CIF files including X-ray crystallographic data for
3b-OTf and 5-OTf. This material is available free of charge via
the Internet at http://pubs.acs.org..
AUTHOR INFORMATION
Corresponding Author
*H.A.: fax, (33)1-44-27-38-41; e-mail, hani.amouri@upmc.fr.
C.A.: fax, (33)1-44-27-73-60; e-mail, corinne.aubert@upmc.fr.
■
1
demonstrated by H NMR of some representative compounds 2a−
cSe-OTf.
[Cp*Ru(η6-C6H5-P(p-tol)2)Se][OTf] (2aSe-OTf). 1H NMR (300
MHz, CD2Cl2): δ (ppm) 7.59 (m, H arene, 4H), 7.29 (m, H arene,
4H), 6.33 (m, H π-arene, 1H), 6.12 (m, H π-arene, 2H), 5.86 (m, H π-
arene, 2H), 2.45 (s, 2 p-Me, 6H), 2.02 (s, Cp*, 15H). 31P NMR (121
MHz, CD2Cl2): δ (ppm) 35.0 (1JP−Se = 772 Hz).
Present Address
†V.G.: Universite
́
Paris-Sud, UMR CNRS 8182, Orsay 91405,
France, and ICSN, 91198 Gif-sur-Yvette, France.
Notes
[Cp*Ru(η6-p-MeC6H4-P(p-tol)2)Se][OTf] (2bSe-OTf). 1H NMR
(300 MHz, CD2Cl2): δ (ppm) 7.62 (m, H arene, 4H), 7.36 (m, H
arene, 4H), 6.36 (m, H π-arene, 2H), 5.99 (m, H π-arene, 2H), 2.45
(s, 2 p-CH3 arene, 6H), 2.39 (s, p-CH3 π-arene, 3H), 1.97 (s, Cp*,
15H). 31P NMR (121 MHz, CD2Cl2): δ (ppm) 33.7 (1JP−Se = 771 Hz).
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This work was supported by the CNRS, UPMC, IUF, and
Agence Nationale de la Recherche (grant SACCAOR, ANR-09-
BLAN0108), which we gratefully acknowledge. We used the
computing facility of the CRIHAN (project 2006-013).
1
[Cp*Ru(η6-p-MeOC6H4-P(p-tol)2)Se][OTf] (2cSe-OTf). H NMR
(300 MHz, CD2Cl2): δ (ppm) 7.62 (m, H arene, 4H), 7.35 (m, H
arene, 4H), 6.40 (m, H π-arene, 2H), 6.07 (m, H π-arene, 2H), 3.88
(s, p-OCH3 π-arene, 3H), 2.45 (s, 2 p-CH3 arene, 6H), 2.01 (s, Cp*,
15H). 31P NMR (121 MHz, CD2Cl2): δ (ppm) 33.3 (1JP−Se = 768 Hz).
[Cp*Ru(η6-o-MeC6H4-P(p-tol)2)Se][OTf] (2dSe-OTf). 31P NMR
(121 MHz, CD2Cl2): δ (ppm) 31.2 (1JP−Se = 769 Hz).
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General Procedure for Kinetic Studies. To a prestirred (10 min)
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H
dx.doi.org/10.1021/om301101z | Organometallics XXXX, XXX, XXX−XXX

Organometallics
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dx.doi.org/10.1021/om301101z | Organometallics XXXX, XXX, XXX−XXX