Transformations of alkynes at a cyclotriphosphato ruthenium complex

Article abstract of DOI:10.1021/om3009926

Photolysis of the cyclotriphosphato complex (PPN)[Ru(P₃O ₉)(η⁶-C₆H₆)] (2) with bpy (2,2′-bipyridyl) in alcohols generated a violet solution of (PPN)[Ru(P₃O₉)(bpy)(ROH)] (3) with a labile alcohol ligand. Complexes 3 were readily oxidized during recrystallization to give the Ru(III) alkoxo complexes (PPN)[Ru(OR)(P₃O₉)(bpy)] (4). Treatment of 3 with internal alkynes led to selective formation of η²-alkyne complexes (PPN)[Ru(P₃O₉)(bpy) (η²-RCi - CR′)] (7), which did not undergo vinylidene rearrangement under heating and photoirradiation conditions in contrast to its dppe analogues. On the other hand, diphenylacetylene complex 7c (R = R′ = Ph) gave the α-ketocarbene complex (PPN)[Ru(P₃O ₉)(bpy)(=CPhCOPh)] (8) on reaction with m-CPBA. This observation provides a very rare example for the direct and controlled oxidation of a coordinated alkyne ligand. Reactions of 3 with the terminal alkynes in alcohols and in DMF afforded the alkoxycarbene complexes (PPN)[Ru(P₃O ₉)(bpy){=C(OR)CH₂CR′}] (9) and the carbonyl complex (PPN)[Ru(P₃O₉)(CO)(bpy)] (12), respectively, presumably by way of vinylidene intermediates.

Full text of DOI:10.1021/om3009926

Article
pubs.acs.org/Organometallics
Transformations of Alkynes at a Cyclotriphosphato Ruthenium
Complex
Keiichiro Kanao,† Yousuke Ikeda,† Kazuhiro Kimura,† Sou Kamimura,‡ Yoshiaki Tanabe,§
Yuichiro Mutoh,† Masakazu Iwasaki,∥ and Youichi Ishii*,†
†Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, Kasuga, Bunkyo-ku, Tokyo, 112-8551,
Japan
‡Institute of Industrial Science, The University of Tokyo, Komaba, Meguro-ku, Tokyo, 153-8505, Japan
§Institute of Engineering Innovation, School of Engineering, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan
∥Department of Applied Chemistry, Faculty of Engineering, Saitama Institute of Technology, Okabe, Saitama, 369-0293, Japan
S
* Supporting Information
ABSTRACT: Photolysis of the cyclotriphosphato complex
(PPN)[Ru(P3O9)(η6-C6H6)] (2) with bpy (2,2′-bipyridyl) in
alcohols generated a violet solution of (PPN)[Ru(P3O9)(bpy)-
(ROH)] (3) with a labile alcohol ligand. Complexes 3 were
readily oxidized during recrystallization to give the Ru(III) alkoxo
complexes (PPN)[Ru(OR)(P3O9)(bpy)] (4). Treatment of 3
with internal alkynes led to selective formation of η2-alkyne
complexes (PPN)[Ru(P3O9)(bpy)(η2-RCCR′)] (7), which
did not undergo vinylidene rearrangement under heating and
photoirradiation conditions in contrast to its dppe analogues. On the other hand, diphenylacetylene complex 7c (R = R′ = Ph)
gave the α-ketocarbene complex (PPN)[Ru(P3O9)(bpy)(CPhCOPh)] (8) on reaction with m-CPBA. This observation
provides a very rare example for the direct and controlled oxidation of a coordinated alkyne ligand. Reactions of 3 with the
terminal alkynes in alcohols and in DMF afforded the alkoxycarbene complexes (PPN)[Ru(P3O9)(bpy){C(OR)CH2CR′}]
(9) and the carbonyl complex (PPN)[Ru(P3O9)(CO)(bpy)] (12), respectively, presumably by way of vinylidene intermediates.
3−
P3O10H2 ligand [Co(P3O8(OH)2)(tacn)] (tacn = 1,4,7-
triazacyclononane).6b
INTRODUCTION
■
Organometallic complexes with O-donor ancillary ligand sets
have received much attention, because they can serve as
molecular models for heterogeneous metal catalysts.1 O-donor
ligands have also been expected to endow metal centers with
novel reactivities different from those of organometallic
complexes with commonly used P- and N-donor ligands. In
this context, molecular complexes with cyclophosphates
(PnO3nn−),2 which are composed of n corner-sharing PO4
tetrahedra and have oxygen donor atoms in a regularly cyclic
arrangement, can be a potential candidate for the molecular
model of the oxo surface in solid catalysts. In particular,
cyclotriphosphato (P3O93−) complexes have unique structures
closely related to the hydroxyapatite-supported metal catalysts
that are known to be effective for aerobic oxidations of organic
substrates, carbon−carbon bond-forming reactions, dehaloge-
nation of haloarenes, and fixation of carbon dioxide into
epoxide.3 Although several molecular transition-metal com-
Meanwhile, we have been engaged in synthesizing organo-
metallic complexes on a cyclophosphato platform in recent
years and found that mono- and multinuclear complexes with
Pt, Ru, Nb, Ta, Rh2, Rh4, Pd2, Ru2, Ti2, and Ti3 cores can be
obtained by using the P3O9 and P4O12 ligands.7 These
complexes exhibit unique structural and chemical properties
based on the circular array of P−O groups as an effective σ-
donor set. Among those, the anionic ruthenium P3O9 complex
(PPN)[Ru(P3O9)(MeOH)(dppe)] (1; PPN = (Ph3P)2N+,
dppe = Ph2PCH2CH2PPh2), which is derived from (PPN)-
[Ru(P3O9)(η6-C6H6)] (2), can affect the vinylidene rearrange-
ment of general internal alkynes via the 1,2-migration of alkyl,
aryl, and acyl groups.7d,8 Prior to our studies, this type of
reaction has been reported only for the transformation of
acylalkynes9 and regarded to be hardly achievable with
common internal alkynes.10
plexes with P3O9 have been isolated,4 their reactivities still
3−
The facile photolysis of 2 to give 1 has prompted us to
investigate the generation of analogous active complexes from 2
by using another bidentate ligand, 2,2′-bipyridyl (bpy), and
their reactivities with organic substrates, particularly with
remain unexplored. Klemperer and co-workers, pioneers in this
field, revealed the epoxidation of the cod (1,5-cyclooctadiene)
ligand of the iridium complex [Ir(cod)(P3O9)]2− by O2.5
Cummins and co-workers described the facile hydrolytic
3−
cleavage of a P−O bond in P3O9 in the presence of a cobalt
Received: October 22, 2012
Published: January 8, 2013
complex6a to give the known cobalt complex with the
© 2013 American Chemical Society
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alkynes. Now, we have developed novel reactive (bpy)(alcohol)
complexes (PPN)[Ru(P3O9)(bpy)(ROH)] (3) and found that
3 exhibits reactivities different from those of 1.
RESULTS AND DISCUSSION
■
Synthesis of Ruthenium-P3O9 Complexes with bpy or
Pyridine Ligands. When a solution of 2 and bpy in MeOH
was irradiated with an ultra-high-pressure Hg lamp for 1 h, the
color of the reaction mixture turned to violet. The 31P{1H}
NMR spectrum of this solution displays one triplet at δ −17.2
(2JPP = 20 Hz) and one doublet at δ −22.4 (2JPP = 20 Hz),
suggesting that the replacement of the benzene ligand by bpy
yields the product with a Cs symmetry. Tentatively, this
product is deduced to be the Ru(II) methanol complex
(PPN)[Ru(P3O9)(bpy)(MeOH)] (3a) (Scheme 1) on the
basis of the following observations, although all attempts to
isolate 3a in a pure form failed.
Figure 1. EPR spectra of 4a in MeOH at −150 °C.
Scheme 1. Photolysis of 2 in Alcohols, Acetonitrile, and
Pyridine
Figure 2. ORTEP drawings for the anionic part of 4a·THF (50%
thermal ellipsoids). Hydrogen atoms and solvating THF molecule are
omitted for clarity. Selected bond lengths (Å) and angles (deg): Ru1−
O1, 2.106(3); Ru1−O2, 2.107(4); Ru1−O3, 2.077(4); Ru1−N1,
1.994(4); Ru1−N2, 2.002(4); Ru1−O10, 1.933(4); O1−Ru1−O2,
91.7(1); O1−Ru1−O3, 89.8(1); O2−Ru1−O3, 88.7(1); N1−Ru1−
N2, 79.6(1); Ru1−O10−C11, 116.9(4).
adopts an octahedral geometry, where the three oxygen atoms
of the P3O9 ligand occupy the facial positions, and the bpy and
methoxido ligands are located at the other fac coordination
sites. The Ru−OMe bond length of 1.933(4) Å is comparable
to the values in the alkoxo Ru(III) complexes, such as
[RuCl(OMe)(py)4](ClO4) (1.937(2) Å),11a [TpRuCl(OMe)-
(PCy3)] (Tp = hydrotris(pyrazolyl)borato, Cy = cyclohexyl;
1.943(1) Å),11b and [TpiPrRu(OMe)(Ph2PCH2P(O)Ph2-
κ1P,κ1O)][PF6] (TpiPr = hydrotris(3,5-diisopropylpyrazolyl)-
borato; 1.933(3) Å).11c The three Ru−O(P) bond lengths (av,
2.097 Å) are longer than the Ru−OMe bond distance. The
photolysis of 2 in EtOH and acetone−PhOH in the presence of
bpy initially generated the violet Ru(II) species (PPN)[Ru-
(P3O9)(bpy)(ROH)] (3, R = Et, Ph), which was confirmed by
their 31P{1H} NMR spectra analogous to that of 3a (R = Et, δ
Complex 3a was transformed into the Ru(III) complex
(PPN)[Ru(P3O9)(OMe)(bpy)] (4a) during recrystallization
from dichloromethane/methanol−diethyl ether under a dry-
nitrogen atmosphere. This observation is in sharp contrast to
the related dppe complex 1, which can be readily isolated and
shows no symptom of oxidation during usual handling. The
31P{1H} and 1H NMR spectra of 4a do not show any
resonances, whereas its EPR spectrum shows signals with g
values of 2.37, 2.25, and 1.87, indicating the paramagnetism of
4a (Figure 1). The structure of 4a has been determined by an
X-ray diffraction study (Figure 2). The ruthenium center in 4a
2
2
−17.9 (t, JPP = 21 Hz), δ −23.7 (d, JPP = 21 Hz); R = Ph, δ
2
2
−18.0 (t, JPP = 21 Hz), δ −24.8 (d, JPP = 21 Hz)). Similar
oxidation also took place during recrystallization to give the
corresponding Ru(III) complexes (PPN)[Ru(P3O9)(OR)-
(bpy)] (4b, R = Et; 4c, R = Ph), and their paramagnetism
and molecular structure of 4c have been confirmed by EPR and
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X-ray analyses, respectively (Figures S1 and S2 in the
Supporting Information).
Similar photolysis of 2 in pyridine resulted in the formation
of (PPN)[Ru(P3O9)(py)3] (6) in high yield (Scheme 1). The
31P{1H} NMR spectrum of 6 shows a singlet at δ −7.5
Although mechanistic details of the oxidation of 3 have not
been clarified, several related oxidations of Ru(II) to Ru(III)
have been reported in the literature. Kirchner and Akita
independently reported that treatment of [TpRuCl(dmf)-
(PCy3)] (dmf = N,N-dimethylformamide) and [TpiPrRuCl-
(Ph2PCH2PPh2)]/AgPF6 with MeOH/O2 afforded [TpRuCl-
(OMe)(PCy3)] and [TpiPrRu(OMe)(Ph2PCH2P(O)Ph2-
κ1P,κ1O)][PF6].11b,c However, even when the photolysis of 2
with bpy in MeOH was conducted under an O2 atmosphere,
the reaction mixture showed 31P{1H} signals assignable to 3a. It
would be reasonable that the high electron density at the
anionic ruthenium in 3 may cause the oxidation during
recrystallization. Actually, IR absorption of the CO ligand in
(PPN)[Ru(P3O9)(CO)(bpy)] (1939 cm−1; vide infra) is lower
in wavenumber than that in the dppe complex (PPN)[Ru-
(P3O9)(CO)(dppe)] (1966 cm−1).
1
assignable to the P3O9 ligand, while the H NMR spectrum
displays only one set of signals ascribed to the o- and m-protons
3
in the three pyridine ligands at δ 8.42 (d, JHH = 5.2 Hz, 6H)
and δ 7.27 (pseudo t, 3JHH = 7.2 Hz, 6H; the p-proton signal is
overlapped with PPN signals), all of which are in accord with
the C3 structure.
Reaction of 3 with Internal Alkynes. To compare the
reactivities of the [RuII(P3O9)(bpy)]− complex with its dppe
analogue, the latter of which provides an active metal site for
the vinylidene rearrangement of internal alkynes,7d reactions of
internal alkynes with 3, 5, and 6 were examined. When the
violet solution of 3a was treated with an excess amount of
DMAD (dimethyl acetylenedicarboxylate) at 70 °C overnight,
the η2-alkyne complex (PPN)[Ru(P3O9)(η2-dmad)(bpy)] (7a)
was selectively obtained in 44% isolated yield as red crystals
(Scheme 2). 7a shows an IR absorption at 1978 cm−1,
The photoreaction of 2 was also applicable to other related
P3O9 ruthenium complexes. Thus, photolysis of 2 with bpy in
acetonitrile afforded the (bpy)(acetonitrile) complex (PPN)-
[Ru(P3O9)(bpy)(MeCN)] (5) as dark red blocks in 66% yield
without oxidation to the corresponding Ru(III) species
(Scheme 1). The 31P{1H} NMR spectrum of 5 displays A2X
type signals (δ −7.5 (d, 2JPP = 22 Hz) and δ −8.2 (t, 2JPP = 22
Scheme 2. Reaction of in Situ Generated 3a with Internal
Alkynes
1
Hz)) attributable to the P3O9 ligand, while the H NMR
spectrum exhibits signals ascribed to the bpy and acetonitrile
ligands, indicating that 5 has a Cs symmetry. The molecular
structure of 5 has been determined by an X-ray analysis to
confirm that the coordination environment around the
ruthenium center in 5 is similar to that in 4a, except that an
acetonitrile ligand binds the ruthenium center instead of the
methoxido ligand (Figure 3). The Ru−NCMe (1.995(3) Å)
and average Ru−O (2.134 Å) bond lengths are comparable to
those in (Bu4N)[Ru(P3O9)(MeCN)3] (1.973 (av) and 2.116
(av) Å, respectively)4f and (Bu4N)[Ru(P3O9)(cod)(MeCN)]
(2.05(1) and 2.12 (av) Å, respectively.4h
indicating the presence of the η2-alkyne ligand. The 31P{1H}
2
NMR spectrum of 7a shows A2X spin signals at δ −7.4 (t, JPP
= 18 Hz) and δ −8.2 (d, 2JHH = 18 Hz) assignable to the P3O9
1
ligand, whereas the H NMR spectrum of 7a exhibits signals
ascribed to the bpy ligand and the coordinated DMAD. The
molecular structure of 7a was further confirmed by an X-ray
analysis (Figure 4a). The orientation of the alkyne unit relative
to the [Ru(P3O9)(bpy)] moiety in 7a is not parallel to the N1−
O1 axis; the Ru−alkyne plane is twisted toward the O3−Ru1−
N1 and O3−Ru1−O1 planes with the angles of 22.5 and 17.3°
(Figure 4b). The symmetrically bound alkyne fragment is bent
back with the angles of 21.7° and 25.1°, respectively, and the
CC bond length at 1.216(4) Å falls in the range of those in
known η2-alkyne complexes8c,9d,12 and is comparable to that in
a related P3O9 complex (PPN)[Ru(P3O9)(η2-MeCCCO2-
Et)(dppe)] (1.169 (8)Å).7d The bond lengths of Ru1−C11
(2.110(3) Å) and Ru1−C12 (2.121(3) Å) in 7a are shorter
than those in (PPN)[Ru(P3O9)(η2-MeCCCO2Et)(dppe)]
(2.130(6) and 2.203(6) Å). Similar reactions of 3a with other
internal alkynes afforded the corresponding η2-alkyne com-
plexes (PPN)[Ru(P3O9)(η2-RCCR′)(bpy)] (7b, R = R′ =
CO2Et; 7c, R = R′ = Ph; 7d, R = Me, R′ = Ph), albeit in lower
isolated yields (Scheme 2).
Figure 3. ORTEP drawing for the anionic part of 5·2MeCN (50%
thermal ellipsoids). Hydrogen atoms and solvating molecules are
omitted for clarity. Selected bond lengths (Å) and angles (deg): Ru1−
O1, 2.142(2); Ru1−O2, 2.152(2); Ru1−O3, 2.107(2); Ru1−N1,
1.995(3); Ru1−N2, 2.001(3); Ru1−N3, 1.980(2); N3−C11,
1.141(4); C11−C12, 1.465(4); O1−Ru1−O2, 88.67(9); O1−Ru1−
O3, 88.52(8); N1−Ru1−N2, 79.9(1); Ru1−N3−C11, 177.6(3); N3−
C11−C12, 177.8(4).
Unfortunately, the conversion of 7 into the corresponding
disubstituted vinylidene complexes could not be observed
either thermally or photochemically despite that the η2-internal
alkyne complexes (PPN)[Ru(P3O9)(η2-RCCR′)(dppe)] and
[CpM(η2-RCCR′)(PP)][BArF ] (M = Ru, Fe; ArF = 3,5-
4
(CF3)2C6H3; PP = (PPh3)2, dppe) have the ability to shift into
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Figure 5. ORTEP drawing for the anionic part of 8·2MeOH (50%
thermal ellipsoids). Hydrogen atoms and solvating MeOH molecules
are omitted for clarity. Selected bond lengths (Å) and angles (deg):
Ru1−O1, 2.1192(18); Ru1−O2, 2.1090(17); Ru1−O3, 2.1864(18);
Ru1−N1, 2.023(3); Ru1−N2, 2.021(2); Ru1−C11, 1.891(3); O10−
C12, 1.235(4); C11−C12, 1.482(3); C12−C13, 1.495(5); C11−C19,
1.472(4); O1−Ru1−O2, 90.88(7); O1−Ru1−O3, 85.86(7); O2−
Ru1−O3, 87.47(7); N1−Ru1−N2, 80.01(9); Ru1−C11−C19,
128.13(15); Ru1−C11−C12, 117.8(2); C12−C11−C19, 113.9(2).
Figure 4. (a) ORTEP drawing and (b) orientation of the alkyne
ligands for the anionic part of 7a·MeOH·THF (50% thermal
ellipsoids). Hydrogen atoms and solvating molecules are omitted for
clarity. Selected bond lengths (Å) and angles (deg): Ru1−O1,
2.129(2); Ru1−O2, 2.127(2); Ru1−O3, 2.110(2); Ru1−N1,
2.031(2); Ru1−N2, 1.994(2); Ru1−C11, 2.110(3); Ru1−C12,
2.121(3); C11−C12, 1.216(4); O1−Ru1−O2, 91.25(7); O1−Ru1−
O3, 85.42(7); O2−Ru1−O3, 90.79(7); N1−Ru1−N2, 79.75(8);
C11−Ru1−C12, 33.4(1), C12−C11−C13, 158.3(3); C11−C12−
C15, 154.9(3).
expected octahedral geometry with a RuC bond length
(1.901(5) Å) similar to those in known α-ketocarbene13 and α-
alkoxycarbonylcarbene14 complexes of ruthenium. The P3O9
ligand in 8 is not symmetrically bonded to the ruthenium. The
Ru−O3 bond distance trans to the carbene ligand is longer
than the Ru−O1 and Ru−O2 bond lengths, indicating the
strong trans influence of the carbene ligand. Although α-
ketocarbenoid species have been proposed as intermediates for
oxidation of alkynes in some cases, particularly gold-catalyzed
reactions,15 most α-ketocarbene complexes have been prepared
from metal fragments with α-diazocarbonyl compounds. Metal-
mediated and metal-catalyzed intermolecular oxidation of
alkynes often suffers from overoxidation.16 Consequently, the
present observation provides a rare example for the direct and
controlled oxidation of a coordinated alkyne ligand at
ruthenium to form the α-ketocarbene ligand; the only example
of such a monooxygenation of diphenylacetylene and their
derivatives at a transition-metal complex has been observed for
the CpMn system with dimethyldioxirane as the oxidizing
reagent.17
the η1-disubstituted vinylidene complexes (PPN)[Ru(P3O9)-
{CC(R)R′}(dppe)] and [CpM{CC(R)R′}(PP)]-
[BArF ] via 1,2-migration of aryl and alkyl groups.7d,8
4
On the other hand, monooxygenation of the PhCCPh
ligand in 7c was observed on reaction with m-CPBA. Thus,
when complex 7c was allowed to react with m-CPBA (1.4
equiv) at room temperature, the α-ketocarbene complex
(PPN)[Ru(P3O9)(CPhCOPh)(bpy)] (8) was obtained in
70% yield (Scheme 3). The 13C{1H} NMR spectrum of 8
Scheme 3. Oxidation of η2-Diphenylacetylene
Nitrile complex 5 and tris(pyridine) complex 6 were inert
toward alkynes, such as DMAD and HCCCO2Me, even at
elevated temperature, though the related bis(nitrile) complex
[RuCl2(MeCN)2(PPri3)2] smoothly reacts with terminal
alkynes to give the corresponding vinylidene complexes
[RuCl2{CCHR}(PPri3)2].18
displays signals at δ 210.4 and δ 323.6 characteristic of a
carbonyl group and a carbene ligand, respectively. The IR
spectrum of 8 also shows a strong absorption at 1590 cm−1 due
to the CO stretch vibration of the carbonyl group. The
molecular structure of 8 was determined by an X-ray analysis to
confirm that one of the η2-alkyne carbons was oxygenated to
form the α-ketocarbene ligand (Figure 5). Complex 8 has the
Reaction of 3 with Terminal Alkynes. When the terminal
alkynes were used instead of internal alkynes, subsequent
reactions of η2-alkynes were observed. Thus, the reactions of
the alcohol solution of 3a and 3b with an excess amount of a
terminal alkyne, such as HCCCO2Me and HCCPh,
resulted in the formation of the methoxy- and ethoxycarbene
complexes (PPN)[Ru(P3O9){C(OR)CH2R′}(bpy)] (9a: R
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a
Scheme 4. Reactions of in Situ Generated 3 with Terminal Alkynes
a
Reaction conditions: (a) terminal alkynes (excess), ROH/C2H4Cl2, 60−70 °C; (b) HCCC(OH)Ph2 (excess), MeOH/C2H4Cl2, 70 °C,
overnight.
= Me, R′ = CO2Me; 9b: R = Et, R′ = Ph), respectively (Scheme
4). Their 31P{1H} NMR spectra show A2X signals attributable
to the P3O9 ligand, indicating the formation of complexes with
a CS symmetry. The 13C{1H} NMR spectra display downfield
signals at δ 302.2 (9a) and δ 309.4 (9b) characteristic of a
carbene ligand; they have predicted that the carbene moiety
preferentially lies in the symmetry plane of the molecule.19 The
Ru1−C11 bond length of 1.855(5) Å is comparable with those
in related alkoxycarbene complexes of ruthenium (1.787−2.016
Å).20 The vinyl−carbene complex (PPN)[Ru(P3O9){C-
(OMe)CHCPh2}(bpy)] (9c) was also obtained from the
reaction of 3a with HCCC(OH)Ph2, whose structure has
been clarified by an X-ray analysis (Figure S3 in the Supporting
Information).
1
carbene ligand, and the H NMR spectra signals assignable to
the OMe and OEt groups. The molecular structure of 9a has
been confirmed by X-ray crystallography, and its ORTEP
drawing is shown in Figure 6. The ruthenium atom in 9a adopts
an octahedral geometry, and the plane of the carbene fragment
bisects the N−Ru−N angle. Fenske and co-workers have
calculated the total energies of [CpRu(CH2)(PH3)2]+ for
both the vertical and the alternate horizontal geometries of the
These Fischer-type carbene complexes 9 were presumably
formed via the nucleophilic attack of an alcohol molecule on
the α-carbon of the vinylidene and allenylidene ligands in the
intermediary complexes (PPN)[Ru(P3O9)(CCHR′)-
(bpy)] (10) and (PPN)[Ru(P3O9)(CCCPh2)(bpy)]
(11), because it is well-known that terminal alkynes are readily
converted into the corresponding vinylidenes at metal
complexes.10b,21 In addition, the α-carbon of a vinylidene
ligand is electrophilic and smoothly attacked by alcohols, giving
an alkoxycarbene ligand.12f,22 We attempted to isolate the
intermediary vinylidene complexes 10 in the absence of
alcohols. After the photolysis of 2 with bpy in DMF, the
resulting solution was treated with an excess amount of HC
CCO2Me and HCCPh at 110 °C (Scheme 5). However, the
carbonyl complex (PPN)[Ru(P3O9)(CO)(bpy)] (12) was
isolated as the final product (48−69% isolated yields) instead
of the vinylidene complexes 10. Alternatively, the carbonyl
complex 12 is also synthesized by the reaction of 3a with CO
(73% isolated yield). The 31P{1H} NMR spectrum of 12
2
exhibits A2X signals (δ −7.6 (d, JPP = 20 Hz) and δ −11.4 (t,
2JPP = 20 Hz)) assignable to the P3O9 ligand, and the IR
spectrum shows a strong CO absorption (1939 cm−1). The
structure of 12 has also been established crystallographically
(Figure 7).
Figure 6. ORTEP drawings for the anionic part of 9a (50% thermal
ellipsoids). Hydrogen atoms are omitted for clarity. Selected bond
lengths (Å) and angles (deg): Ru1−O1, 2.125(2); Ru1−O2, 2.130(3);
Ru1−O3, 2.216(3); Ru1−N1, 1.994(3); Ru1−N2, 2.022(3); Ru1−
C11, 1.855(5); O10−C11, 1.325(6); O10−C12, 1.445(6); C11−C13,
1.544(6); O1−Ru1−O2, 91.6(1); O1−Ru1−O3, 84.8(1); O2−Ru1−
O3, 86.4(1); N1−Ru1−N2, 79.9(1); Ru1−C11−O10, 138.8(3);
O10−C11−C13, 104.7(4); C11−O10−C12, 119.0(4).
Since 12 was not formed in the absence of the terminal
alkynes, the carbon atom of the carbonyl ligand should be
derived from the terminal alkynes. In addition, toluene was
detected by GLC analysis of the reaction mixture with
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complexes were found to be inert toward substitution by
alkynes, photolysis of 2 with bpy in ROH (R = Me, Et, Ph)
furnished violet solutions of (PPN)[Ru(P3O9)(bpy)(ROH)]
(3) with a labile ROH ligand. The alcohol complexes 3 failed to
be isolated, because they were converted into the Ru(III)
alkoxo complexes (PPN)[Ru(P3O9)(OR)(bpy)] (4) during
recrystallization. However, complexes 3 formed in situ could be
further converted into the η2-internal alkyne complexes
(PPN)[Ru(P3O9)(η2-RCCR′)(bpy)] (7) on reactions with
internal alkynes. Unlike the reaction of the dppe complex
(PPN)[Ru(P3O9)(η2-RCCR′)(dppe)], the internal alkyne
ligands were not converted into the corresponding vinylidene
even under heating and photoirradiation. On the other hand,
monooxygenation of an η2-diphenylacetylene ligand took place
to give the α-ketocarbene complex as the sole product, which
provides a rare example of selective monooxygenation of an
alkyne ligand. When terminal alkynes were allowed to interact
with 3 in alcohols, the alkoxycarbene complexes (PPN)[Ru-
(P3O9){C(OR)CH2R′}(bpy)] (9) were obtained presum-
ably via the formation of an intermediary vinylidene complex
and the subsequent attack of alcohols on the α-carbon of the
vinylidene ligand. Photolysis of 2 in the presence of bpy,
followed by treatment with terminal alkynes in DMF, resulted
in the CC triple bond scission of the terminal alkynes to give
the carbonyl complex (PPN)[Ru(P3O9)(CO)(bpy)] (12). In
addition to the reactivities observed for (PPN)[Ru(P3O9)-
(dppe)(L)] species,7d these results clearly demonstrated that
P3O9 complexes can activate a wide range of alkyne molecules,
including internal alkynes. Further investigation into P3O9
complexes of transition metals other than ruthenium is now
in progress.
Scheme 5. Reaction of 2 with Terminal Alkynes in DMF
Giving CO Complex 12
EXPERIMENTAL SECTION
■
General Remarks. All manipulations were carried out under an
atmosphere of dry dinitrogen by means of standard Schlenk
techniques unless otherwise specified. Dehydrated solvents (diethyl
ether, hexane, tetrahydrofuran) were purchased from a commercial
source. Other solvents were dried and distilled by common procedures
and degassed before use. (PPN)[Ru(P3O9)(η6-C6H6)]·0.5CH2Cl2
(2·0.5CH2Cl2)7d was prepared according to the literature methods,
while the other reagents were obtained from commercial sources and
1
used without further purification. H, 13C{1H}, and 31P{1H} NMR
spectra were recorded on a JEOL ECA-500 spectrometer (1H, 500
MHz; 31P, 202 MHz; 13C, 126 MHz). IR spectra were recorded on a
JASCO FT/IR-410 spectrometer. Elemental analyses were performed
on a Perkin-Elmer 2400 II CHN analyzer. X-band EPR spectra were
measured on a JEOL FE-2XG spectrometer with 100 kHz field
modulation of 0.5 mT. Amounts of the solvent molecules in the
crystals were determined not only by elemental analyses but also by 1H
NMR spectroscopy.
Figure 7. ORTEP drawing for the anionic part of 12·CH2Cl2 (50%
thermal ellipsoids). Hydrogen atoms are omitted for clarity. Selected
bond lengths (Å) and angles (deg): Ru1−O1, 2.126(5); Ru1−O2,
2.125(6); Ru1−O3, 2.146(5); Ru1−N1, 2.024(7); Ru1−N2, 2.032(7);
Ru1−C11, 1.813(8); O10−C11, 1.17(1); O1−Ru1−O2, 90.0(2);
O1−Ru1−O3, 86.2(2); O2−Ru1−O3, 88.5(2); N1−Ru1−N2,
80.2(3); Ru1−C11−O10, 177.2(7).
(PPN)[Ru(OMe)(P3O9)(bpy)]·MeOH (4a·MeOH). A mixture of
2·0.5CH2Cl2 (121.4 mg, 0.122 mmol) and bpy (20.4 mg, 0.131 mmol)
in methanol (4 mL) was irradiated with an ultra-high-pressure Hg arc
lamp (520 W) for 1 h. The resulting violet solution was evaporated to
dryness, and the residue was recrystallized from (dichloromethane/
methanol)−diethyl ether to afford (PPN)[Ru(OMe)(P3O9)-
(bpy)]·MeOH (4a·MeOH) as red crystals (87.0 mg, 0.079 mmol,
65% yield). IR (KBr, cm−1): 1311 (s), 1286 (s), 1113 (s), 1027 (m).
EPR (MeOH, −150 °C): g = 2.37, 2.25, 1.87. Anal. Calcd for
C48H45N3O11P5Ru: C, 52.61; H, 4.14; N, 3.83. Found: C, 52.23; H,
3.83; N, 3.84. Orange needles of 4a·THF suitable for X-ray analysis
were obtained by further recrystallization from (tetrahydrofuran/
methanol)−diethyl ether.
phenylacetylene, albeit in low yield (10%). Considering
precedent papers for neutral and cationic vinylidene complexes
of ruthenium,18,21a,23 12 was probably generated as follows.
Nucleophilic attack of an adventitious water molecule on the α-
carbon of the vinylidene ligand in the intermediary 10 forms
hydroxycarbene species 13, which undergoes enol-to-keto
tautomerization, leading to an acylruthenium species. This
species subsequently undergoes decarbonylation to give 12.
CONCLUSION
■
By utilizing the photolysis of (PPN)[Ru(P3O9)(η6-C6H6)] (2)
as a key reaction, we have explored new reactivities of
ruthenium P3O9 complexes. While nitrile and tris(pyridine)
(PPN)[Ru(OEt)(P3O9)(bpy)]·0.5CH2Cl2 (4b·0.5CH2Cl2). This
compound was synthesized in a manner similar to that described for
4a except that the solvents for the photoreaction and recrystallization
532
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Organometallics
Article
2
2
were ethanol and dichloromethane/methanol−diethyl ether, respec-
tively. Red plates (78% yield). IR (KBr, cm−1): 1309 (s), 1275 (s),
1113 (s), 1035 (m), 954 (s). EPR (CH2Cl2, −150 °C): g = 2.36, 2.24,
1.89. Anal. Calcd for C48.5H44ClN3O10P5Ru: C, 52.00; H, 3.96; N, 3.75.
Found: C, 52.36; H, 3.97; N, 3.82.
(PPN)[Ru(OPh)(P3O9)(bpy)]·0.5CH2Cl2 (4c·0.5CH2Cl2). This
compound was synthesized in a manner similar to that described for
4a except that the reaction with phenol (large excess) was performed
in acetone. Dark red block crystals (35% yield). IR (KBr, cm−1): 1310
(s), 1286 (s), 1113 (s), 950 (s). EPR (CH2Cl2, −150 °C): g = 2.45,
2.29, 1.84. Anal. Calcd for C52.5H44ClN3O10P5Ru: C, 53.97; H, 3.80; N,
3.60. Found: C, 54.13; H, 3.88; N, 3.64. Red crystals of 4c·0.5Et2O
suitable for X-ray analysis were obtained by further recrystallization
from acetone−diethyl ether.
−7.4 (t, JPP = 18 Hz, P3O9), −8.2 (d, JPP = 18 Hz, P3O9). Selected
1H NMR (CD3OD): δ 9.09 (d, 3JHH = 5.5 Hz, 2H, bpy), 8.37 (d, 3JHH
3
= 8.0 Hz, 2H, bpy), 8.08 (pseudo t, JHH ∼7.3 Hz, 2H, bpy), 7.65
(pseudo t, 3JHH ∼ 6.8 Hz, 2H, bpy), 3.71 (s, 6H, Me). Anal. Calcd for
C52.5H45ClN3O13P5Ru: C, 51.80; H, 3.73; N, 3.45. Found: C, 51.59; H,
3.92; N, 3.42. Brown block crystals of 7a·THF·MeOH suitable for X-
ray analysis were obtained by further recrystallization from
(tetrahydrofuran/methanol)−diethyl ether.
(PPN)[Ru(P3 O9 )(η2 -EtO2 CCCO2 Et)(bpy)]·2MeOH
(7b·2MeOH). This compound was synthesized from 2, bpy, and
diethyl acetylenedicarboxylate by a procedure similar to that for 7a (5
equiv of diethyl acetylenedicarboxylate was used) in 37% yield as dark
red crystals. IR (KBr, cm−1): 1987 (m), 1951 (m), 1309 (s), 1286 (s),
1117 (s), 1038 (m), 998 (m). 31P{1H} NMR (CD3OD): δ 20.8 (s,
2
2
(PPN)[Ru(P3O9)(CO)(dppe)]. A solution of (PPN)[Ru(P3O9)-
(N2)(dppe)]7d (49.7 mg, 0.038 mmol) in C2H4Cl2 was stirred at 60
°C for 1 h under atmospheric CO. The resulting pale yellow solution
was evaporated to dryness, and the residue was recrystallized from
(methanol/acetonitrile)−diethyl ether to afford (PPN)[Ru(P3O9)-
(CO)(dppe)]·0.5MeOH·0.5MeCN as pale yellow crystals (29.1 mg,
0.022 mmol, 57%). IR (KBr, cm−1): 1966 (s, CO). 31P{1H} NMR
PPN), −7.5 (t, JPP = 18 Hz, P3O9), −8.2 (d, JPP = 18 Hz, P3O9).
Selected 1H NMR (CD3OD): δ 9.09 (d, 3JHH = 5.0 Hz, 2H, bpy), 8.38
(d, 3JHH = 7.5 Hz, 2H, bpy), 8.08 (pseudo t, 3JHH ∼ 7.0 Hz, 2H, bpy),
7.66−7.56 (m, 14H, bpy and o-H of PPN), 4.16 (q, 4H, 3JHH = 7.2 Hz,
CH2CH3), 1.24 (t, 6H, JHH = 7.2 Hz, CH2CH3). Anal. Calcd for
C56H56N3O15P5Ru: C, 53.09; H, 4.46; N, 3.32. Found: C, 53.03; H,
4.26; N, 3.43.
3
2
(CD2Cl2): δ 65.2 (s, dppe), 20.8 (s, PPN), −10.4 (d, JPP = 19 Hz,
( P P N ) [ R u ( P 3 O 9 ) ( η 2 - P h C  C P h ) ( b p y ) ] · 0 . 5 C H 2 C l 2
(7c·0.5CH2Cl2). A mixture of 2·0.5CH2Cl2 (180.7 mg, 0.181 mmol)
and bpy (41.4 mg, 0.265 mmol) in methanol (4 mL) was irradiated
with an ultra-high-pressure Hg arc lamp (520 W) for 15 min. To the
resulting violet solution was added diphenylacetylene (67.2 mg, 0.377
mmol), and the mixture was refluxed for 2 h. This reaction mixture
was passed through a column of Sephadex LH-20 using methanol as
an eluent, and the third violet band was collected. Recrystallization
from (methanol/dichloromethane)−diethyl ether afforded (PPN)-
[Ru(P3O9)(η2-PhCCPh)(bpy)]·0.5CH2Cl2 (7c·0.5CH2Cl2) as dark
purple crystals (50.7 mg, 0.040 mmol, 22% yield). IR (KBr, cm−1):
1993 (w), 1304 (s), 1282 (s), 1185 (m), 1126 (s), 998 (m). 31P{1H}
NMR (CD3OD): δ 20.8 (s, PPN), −5.7 (t, 2JPP = 19 Hz, P3O9), −8.2
(d, 2JPP = 19 Hz, P3O9). Selected 1H NMR (CD3OD): δ 8.98 (d, 3JHH
= 6.0 Hz, 2H, bpy), 8.22 (d, 3JHH = 8.0 Hz, 2H, bpy), 7.79 (pseudo t,
2
1
P3O9), −12.5 (t, JPP = 22 Hz, P3O9). H NMR (CD2Cl2): δ 7.93−
7.36 (m, 50H, Ar), 2.97−2.53 (m, 4H, CH2 of dppe). 13C{1H} NMR
(CD2Cl2): δ 200.0 (t, JCP = 19 Hz, CO). Anal. Calcd for
2
C64.5H57.5N1.5O10.5P7Ru: C, 57.15; H, 4.18; N, 3.22. Found: C,
56.78; H, 4.31; N, 2.96.
(PPN)[Ru(P3O9)(bpy)(MeCN)]·2MeCN (5·2MeCN). A mixture of
2·0.5CH2Cl2 (35.2 mg, 0.035 mmol) and bpy (7.1 mg, 0.045 mmol) in
acetonitrile (2 mL) was irradiated with an ultra-high-pressure Hg arc
lamp (520 W) overnight. The resultant violet solution was evaporated
to dryness, and the residue was recrystallized from acetonitrile−diethyl
ether to afford (PPN)[Ru(P3O9)(bpy)(MeCN)]·2MeCN (5·2MeCN)
as dark red block crystals (27.0 mg, 0.023 mmol, 66%). IR (KBr,
cm−1): 2256 (m), 1301 (s) 1272 (s), 1131 (s), 1117 (s). 31P{1H}
NMR (CD3OD): δ 20.8 (s, PPN), −7.5 (d, 2JPP = 22 Hz, P3O9), −8.2
(t, 2JPP = 22 Hz, P3O9). Selected 1H NMR (CD3OD): δ 9.23 (d, 3JHH
= 5.5 Hz, 2H, bpy), 8.32 (d, 3JHH = 8.0 Hz, 2H, bpy), 7.85 (pseudo t,
3JHH ∼ 7.8 Hz, 2H, bpy), 7.55−7.49 (m, 14H, m-H of PPN and bpy),
2.31 (s, 3H, coordinated MeCN), 2.03 (s, 6H, free MeCN). Anal.
Calcd for C52H47N6O9P5Ru: C, 54.03; H, 4.10; N, 7.27. Found: C,
53.70; H, 4.10; N, 7.28.
3JHH ∼ 7.5 Hz, 2H, bpy), 7.31 (pseudo t, JHH ∼ 6.5 Hz, 2H, bpy),
7.21−7.14 (m, 10H, Ph). Anal. Calcd for C60.5H49ClN3O9P5Ru: C,
57.97; H, 3.94; N, 3.35. Found: C, 57.76; H, 4.27; N, 3.35.
3
(PPN)[Ru(P3O9)(η2-MeCCPh)(bpy)]·MeOH (7d·MeOH). This
compound was synthesized from 2, bpy, and 1-phenyl-1-propyne by a
procedure similar to that for 7c (6 equiv of 1-phenyl-1-propyne was
used) in 33% yield as dark purple crystals. IR (KBr, cm−1): 2021 (w),
1289 (s), 1183 (m), 1162 (m), 1123 (s), 1021 (m), 998 (m). 31P{1H}
NMR (CD3OD): δ 20.8 (s, PPN), −6.1 (t, 2JPP = 19 Hz, P3O9), −8.2
(d, 2JPP = 19 Hz, P3O9). Selected 1H NMR (CD3OD): δ 9.20 (d, 3JHH
= 5.0 Hz, 2H, bpy), 8.19 (d, 3JHH = 8.0 Hz, 2H, bpy), 7.78 (pseudo t,
3JHH ∼ 7.5 Hz, 2H, bpy), 7.31 (pseudo t, 3JHH ∼ 6.3 Hz, 2H, bpy), 7.19
(t, 3JHH = 7.5 Hz, 1H, p-H of CCPh), 7.01 (t, 3JHH = 7.5 Hz, 2H, m-
H of CCPh), 6.81 (d, 3JHH = 7.5 Hz, 2H, o-H of CCPh), 2.27 (s,
3H, CCMe). Anal. Calcd for C56H50N3O10P5Ru: C, 56.95; H, 4.27;
N, 3.56. Found: C, 56.63; H, 4.16; N, 3.65.
(PPN)[Ru(P3O9)(py)3]·0.25CH2Cl2 (6·0.25CH2Cl2). A solution of
2·0.5CH2Cl2 (148.5 mg, 0.149 mmol) in pyridine (5 mL) was
irradiated with an ultra-high-pressure Hg arc lamp (520 W) overnight.
The red solution was evaporated to dryness, and the residue was
recrystallized from (dichloromethane/pyridine)−diethyl ether to
afford orange crystals of (PPN)[Ru(P3O9)(py)3]·0.25CH2Cl2
(6·0.25CH2Cl2) (143.1 mg, 0.126 mmol, 85% yield). IR (KBr,
cm−1): 1308 (s), 1292 (s), 1260 (m), 1152 (s), 1116 (s), 995 (s).
31P{1H} NMR (CD3OD): δ 20.8 (s, PPN), −7.5 (s, P3O9). Selected
1H NMR (CD3OD): δ 8.42 (d, 3JHH = 5.2 Hz, 6H, o-H of py), 7.74−
7.71 (m, 9H, p-H of py and PPN), 7.27 (pseudo t, 3JHH ∼ 7.2 Hz, 6H,
m-H of py). Anal. Calcd for C51.25H45.5Cl0.5N4O9P5Ru: C, 54.23; H,
4.04; N, 4.94. Found: C, 54.47; H, 4.33; N, 4.98.
(PPN)[Ru(P3O9)(CPhCOPh)(bpy)]·MeOH (8·2MeOH). A mix-
ture of 7c·0.5CH2Cl2 (103.0 mg, 0.082 mmol) and m-CPBA (19.4 mg,
0.112 mmol) in dichloromethane (4 mL) was stirred at room
temperature for 24 h. The solution was evaporated to dryness, the
residue was dissolved in methanol, which was passed through a
column of Sephadex LH-20 using methanol as an eluent, and the green
band eluted was collected. Recrystallization from methanol−diethyl
ether afforded (PPN)[Ru(P3O9)(CPhCOPh)(bpy)]·MeOH
(8·MeOH) as dark green crystals (72.0 mg, 0.057 mmol, 70%
yield). IR (KBr, cm−1): 1590 (s). 31P{1H} NMR (CD3OD): δ 20.8 (s,
(PPN)[Ru(P3O9)(η2-MeO2CCCCO2Me)(bpy)]·0.5CH2Cl2
(7a·0.5CH2Cl2). A mixture of 2·0.5CH2Cl2 (179.0 mg, 0.180 mmol)
and bpy (39.4 mg, 0.252 mmol) in a mixed solvent of methanol (2
mL) and 1,2-dichloroethane (4 mL) was irradiated with an ultra-high-
pressure Hg arc lamp (520 W) for 15 min. To the resulting violet
solution was added dimethyl acetylenedicarboxylate (100 μL, 0.81
mmol), and the mixture was stirred at 70 °C overnight. The solution
was evaporated to dryness, and the residue was dissolved in methanol.
The solution was passed through a column of Sephadex LH-20 using
methanol as an eluent, and the third reddish brown band was
collected. Recrystallization from dichloromethane−(diethyl ether)
afforded (PPN)[Ru(P3O9)(η2-MeO2CCCO2Me)(bpy)]·0.5CH2Cl2
(7a·0.5CH2Cl2) as red crystals (95.9 mg, 0.079 mmol, 44% yield). IR
(KBr, cm−1): 1978 (m), 1713 (s), 1311 (s), 1286 (s), 1118 (s), 1038
(m), 998 (m), 952 (s). 31P{1H} NMR (CD3OD): δ 20.8 (s, PPN),
2
2
PPN), −7.6 (t, JPP = 19 Hz, P3O9), −11.9 (d, JPP = 19 Hz, P3O9).
Selected 1H NMR (CD3OD): δ 8.35 (d, 3JHH = 8.0 Hz, 2H, bpy), 8.10
(d, 3JHH = 7.4 Hz, 2H, COPh), 7.82 (br, 2H, bpy), 7.67 (t, 3JHH = 7.4
Hz, 1H, COPh), 7.59−7.29 (m, 36H, PPN, bpy, and COPh), 7.21 (t,
3JHH = 7.2 Hz, 1H, Ph), 7.07 (d, 3JHH = 6.9 Hz, 2H, Ph), 7.00 (t, 3JHH
=
7.7 Hz, 2H, Ph). Selected 13C{1H} NMR (CD3OD): δ 323.6 (Ru
C), 210.4 (CO). Anal. Calcd for C61H52N3O11P5Ru: C, 58.19; H, 4.16;
N, 3.34. Found: C, 57.84; H, 3.99; N, 3.10. Crystals of 8·2MeOH
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Organometallics
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suitable for X-ray crystallography were obtained by further
recrystallization from (methanol/THF)−diethyl ether.
ethane by drying in vacuo to afford a red powder, which was found to
possess the empirical formula 12·0.5CH2Cl2 (136.7 mg, 0.124 mmol,
69%). IR (KBr, cm−1): 1939 (s, CO), 1309 (s), 1287 (s), 1129 (s),
(PPN)[Ru(P3O9){C(OMe)CH2CO2Me}(bpy)] (9a). A mixture of
2·0.5CH2Cl2 (181.8 mg, 0.182 mmol) and bpy (41.2 mg, 0.264 mmol)
in a mixed solvent of methanol (2 mL) and 1,2-dichloroethane (4 mL)
was irradiated with an ultra-high-pressure Hg arc lamp (520 W) for 15
min. To the resulting violet solution was added methyl propiolate (100
μL, 1.12 mmol), and the mixture was stirred at 60 °C overnight. The
reaction mixture was passed through a column of Sephadex LH-20
using methanol as an eluent, and the third brown band was collected.
Recrystallization from acetonitrile−(hexane/diethyl ether) afforded
(PPN)[Ru(P3O9){C(OMe)CH2CO2Me}(bpy)] (9a) as brown
crystals (92.1 mg, 0.080 mmol, 44% yield). IR (KBr, cm−1): 1736
(s), 1306 (s), 1270 (s), 1184 (m), 1128 (s), 998 (m). 31P{1H} NMR
2
1118 (s). 31P{1H} NMR (CD3OD): δ 20.8 (s, PPN), −7.6 (d, JPP
=
2
20 Hz, P3O9), −11.4 (t, JPP = 20 Hz, P3O9). Selected 1H NMR
(CD3OD): δ 8.77 (d, 3JHH = 5.5 Hz, 2H, bpy), 8.44 (d, 3JHH = 8.0 Hz,
2H, bpy), 8.17 (pseudo t, 3JHH ∼ 7.5 Hz, 2H, bpy), 7.72−7.65 (m, 8H,
bpy and p-H of PPN). Anal. Calcd for C47.5H39ClN3O10P5Ru: C,
51.71; H, 3.56; N, 3.81. Found: C, 51.76; H, 3.65; N, 3.81.
Method (b). A mixture of 2·0.5CH2Cl2 (180.1 mg, 0.181 mmol)
and bpy (39.8 mg, 0.255 mmol) in methanol (6 mL) was irradiated
with an ultra-high-pressure Hg arc lamp (520 W) for 15 min, and the
resultant violet solution was stirred under an atmosphere of carbon
monoxide at 60 °C overnight. The solvent was removed in vacuo, and
the residue was recrystallized from (dichloromethane/methanol)−
diethyl ether to afford 12·2CH2Cl2 (144.9 mg, 0.131 mmol, 73%).
X-ray Crystallographic Study. Diffraction data for 4a·THF,
5·2MeCN, 7a·MeOH·THF, 9a, and 12·2CH2Cl2 were collected at
−165 °C on a Rigaku RAXIS-RAPID imaging plate area detector,
whereas those for 4c·0.5Et2O, 8·2MeOH were collected at −150 °C
on a Rigaku Mercury CCD area detector, both equipped with the
graphite monochromatized Mo Kα radiation (λ = 0.71069 Å).
Reflections were collected for the 2θ range of 5−55°. No significant
decay was observed over the course of data collection. Intensity data
were corrected for numerical absorptions (NUMABS24 for 4a·THF,
5·2MeCN, 7a·MeOH·THF, and 9a) or empirical absorptions
(ABSCOR25 for 12·2CH2Cl2; REQAB26 for 4c·0.5Et2O, 8·2MeOH,
and 9c·2MeOH) and for Lorentz and polarization effects. Corrections
for secondary extinction were further applied for 9c·2MeOH
(coefficient, 29.64(13)).27 The structure solution and refinements
were carried out by using the CrystalStructure package28 except for
refinement of 8·2MeOH, which were performed using SHELXL-97.29
The positions of the non-hydrogen atoms were determined by the
heavy atom Patterson method (PATTY30 for 4c·0.5Et2O) or by the
direct method (SIR9731 for 8·2MeOH; SIR9232 for the others) and
subsequent Fourier syntheses (DIRDIF99).33 The goodness of fit
indicators [∑w(|Fo| − |Fc|)2/(Nobs − Nparams)]1/2 were all refined to the
value of 1.000 except for that of 8·2MeOH (1.080). The atomic
scattering factors were taken from ref 34, and anomalous dispersion
effects were included.35 The values of Δf′ and Δf″ were taken from ref
36.
2
(CD3OD): δ 20.8 (s, PPN), −7.6 (d, JPP = 20 Hz, P3O9), −12.2 (t,
1
3
2JPP = 20 Hz, P3O9). Selected H NMR (CD3OD): δ 8.44 (d, JHH
=
6.5 Hz, 2H, bpy), 8.19 (d, 3JHH = 5.5 Hz, 2H, bpy), 7.98 (pseudo t, J ∼
3
7.0 Hz, 2H, bpy), 7.35 (pseudo t, JHH ∼ 6.3 Hz, 2H, bpy), 3.86 (s,
3H, OMe), 3.64 (s, 3H, OMe), 3.30 (s, 2H, CH2). Selected 13C{1H}
NMR (CD3OD): δ 302.2 (RuC), 167.0 (CO), 160.7 (bpy), 152.9
(bpy), 138.1 (bpy), 125.7 (bpy), 124.2 (bpy), 61.4 (OMe), 52.5
(CO2Me), 49.6 (CH2). The 1H and 13C signals for bpy and the
alkoxycarbene ligands were fully assigned by 1H−1H and 13C−1H
COSY spectra. Anal. Calcd for C51H46N3O12P5Ru: C, 53.32; H, 4.04;
N, 3.66. Found: C, 53.01; H, 4.08; N, 3.96. Dark red platelet crystals of
9a suitable for X-ray analysis were obtained by further recrystallization
from (tetrahydrofuran/methanol)−diethyl ether.
(PPN)[Ru(P3O9){C(OEt)CH2Ph}(bpy)] (9b). This compound
was synthesized in a manner similar to that described for 9a except
that the reaction with ethynylbenzene was performed at 70 °C in
ethanol/1,2-dichloroethane. Dark red block crystals (27% yield). IR
(KBr, cm−1): 1305 (s), 1281 (s), 1186 (m), 1119 (s), 1030 (m), 998
2
(m). 31P{1H} NMR (CD3OD): δ 20.8 (s, PPN), −8.0 (d, JPP = 19
2
Hz, P3O9), −12.5 (t, JPP = 19 Hz, P3O9). Selected 1H NMR
(CD3OD): δ 8.48 (d, 3JHH = 8.0 Hz, 2H, bpy), 8.29 (d, 3JHH = 5.5 Hz,
2H, bpy), 8.00 (pseudo t, J ∼ 7.8 Hz, 2H, bpy), 7.37 (pseudo t, 3JHH
∼
6.0 Hz, 2H, bpy), 7.13−7.05 (m, 3H, m- and p- H of CH2Ph), 6.95 (d,
3
3JHH = 6.0 Hz, 2H, o-H of CH2Ph), 4.42 (q, JHH = 6.8 Hz, 2H,
3
OCH2), 4.10 (s, 2H, CH2Ph), 0.93 (t, JHH = 6.8 Hz, 3H, Me).
Selected 13C{1H} NMR (CD3OD): δ 309.4 (RuC), 161.0, 152.9,
137.8, 125.7, 124.3 (bpy), 136.6 (ipso-C of CH2Ph), 129.8, 129.3 (o-
and m-C of CH2Ph), 127.0 (p-C of CH2Ph), 71.3 (OCH2), 56.4
(CH2Ph), 15.4 (Me). Anal. Calcd for C56H50N3O10P5Ru: C, 56.95; H,
4.27; N, 3.56. Found: C, 57.17; H, 4.31; N, 3.86.
(PPN)[Ru(P3 O9 ){C(OMe)CHCPh2 }(bpy)]·2MeOH
(9c·2MeOH). This compound was synthesized in a manner similar to
that described for 9a except that the reaction with 1,1-diphenyl-2-
propyn-1-ol was performed at 70 °C and (acetonitrile/methanol)−
(hexane/diethyl ether) was used for recrystallization. Dark red block
crystals (50% yield). IR (KBr, cm−1): 1301 (s), 1281 (s), 1127 (s),
1033 (m), 998 (m). 31P{1H} NMR (CD3OD): δ 20.8 (s, PPN), −7.6
For 4a·THF, a relatively large residual density was observed in this
single crystal. Since the density was around the midpoint of the Ru1−
O3 bond (Ru1−O3, 2.077(4)Å; Ru1−residual density, 1.004 Å; O3−
residual density, 1.092 Å), it seems unlikely that any atom is present
there. Consequently, the peak is probably due to the electrons of the
ruthenium atom. For 4c·0.5Et2O, the solvating diethyl ether molecule
was positioned on the center of symmetry and four carbon and one
oxygen atom of the diethyl ether molecule were refined with fixed
isotropic thermal parameters. For 5·2MeCN, one of the solvating
acetonitrile molecules was disordered, and hence two carbon atoms of
the acetonitrile were modeled over two positions with the occupancies
of 60% and 40%, each pair being refined with fixed isotropic thermal
parameters. For 8·2MeOH, one of the solvating methanol molecules
was disordered to be modeled over two positions with the occupancies
of 50% and 50%. The other non-hydrogen atoms were refined on Fo (I
> 3σ(I)) by full-matrix least-squares techniques with anisotropic
thermal parameters, while all the hydrogen atoms were placed at the
calculated positions [C−H distance of 0.95 Å] with fixed isotropic
parameters, except for one methyl hydrogen atom of solvating ether in
4c·0.5Et2O, and hydroxo hydrogen atoms of solvating alcohols in
7a·MeOH·THF, 8·2MeOH, and 9c·2MeOH, while the positions of
hydroxo atoms in 9c·2MeOH were determined by Fourier syntheses.
Details of the crystals and data collection parameters are summarized
in the Supporting Information.
2
2
1
(d, JPP = 19 Hz, P3O9), −12.1 (t, JPP = 19 Hz, P3O9). Selected H
3
3
NMR (CD3OD): δ 8.41 (d, JHH = 8.0 Hz, 2H, bpy), 8.29 (d, JHH
=
5.0 Hz, 2H, bpy), 8.00 (pseudo t, J ∼ 7.8 Hz, 2H, bpy), 7.44 (pseudo t,
3JHH ∼ 6.8 Hz, 2H, bpy), 7.33−7.21 (m, 6H, m- and p-H of CPh2),
7.16 (d, 3JHH = 4.0 Hz, 4H, o-H of CPh2), 6.65 (s, 1H, CHC), 3.53
(s, 3H, OMe). Selected 13C{1H} NMR (CD3OD): δ 303.0 (RuC),
62.3 (OMe). Anal. Calcd for C64H60N3O12P5Ru: C, 58.27; H, 4.58; N,
3.19. Found: C, 58.08; H, 4.28; N, 3.38.
(PPN)[Ru(P3O9)(CO)(bpy)]·2CH2Cl2 (12·2CH2Cl2). Method (a).
The reaction with ethynylbenzene is representative. A mixture of
2·0.5CH2Cl2 (179.7 mg, 0.180 mmol) and bpy (39.6 mg, 0.254 mmol)
in N,N-dimethylformamide (6 mL) was irradiated with an ultra-high-
pressure Hg arc lamp (520 W) overnight. To the resulting violet
solution was added ethynylbenzene (100 μL, 0.91 mmol), and the
mixture was stirred at 110 °C overnight. The solution was evaporated
to dryness, and the residue was recrystallized from (dichloromethane/
methanol)−(diethyl eher) to afford dark red needles of (PPN)[Ru-
(P3O9)(CO)(bpy)]·2CH2Cl2 (12·2CH2Cl2), which were suitable for
crystallographic study. The crystals gave off a part of 1,2-dichloro-
534
dx.doi.org/10.1021/om3009926 | Organometallics 2013, 32, 527−537

Organometallics
Article
29, 2355−2360. (k) Day, V. W.; Klemperer, W. G.; Lockledge, S. P.;
Main, D. J. J. Am. Chem. Soc. 1990, 112, 2031−2033.
(5) Day, V. W.; Eberspacher, T. A.; Klemperer, W. G.; Zhong, B. J.
Am. Chem. Soc. 1994, 116, 3119−3120.
ASSOCIATED CONTENT
* Supporting Information
Text, figures and CIF files giving EPR spectra and crystallo-
graphic data. This material is available free of charge via the
Internet at http://pubs.acs.org.
■
S
(6) (a) Montag, M.; Clough, C. R.; Muller, P.; Cummins, C. C.
̈
Chem. Commun. 2011, 47, 662−664. (b) Haight, G. P.; Hambley, T.
W.; Hendry, P.; Lawrance, G. A.; Sargeson, A. M. J. Chem. Soc., Chem.
Commun. 1985, 488−491. For the related complex [Co(P3O10H2)-
(NH3)3], see the following: (c) Cornelius, R. D.; Gart, P. A.; Cleland,
W. W. Inorg. Chem. 1977, 16, 2799−2805. (d) Merritt, E. A.;
Sundralingam, M. Acta Crystallogr., Sect. B: Struct. Sci. 1981, 37, 1505−
1509.
AUTHOR INFORMATION
Corresponding Author
*E-mail: yo-ishii@kc.chuo-u.ac.jp.
Notes
■
(7) (a) Kamimura, S.; Kuwata, S.; Iwasaki, M.; Ishii, Y. Dalton Trans.
2003, 2666−2673. (b) Kamimura, S.; Kuwata, S.; Iwasaki, M.; Ishii, Y.
Inorg. Chem. 2004, 43, 399−401. (c) Kamimura, S.; Matsunaga, T.;
Kuwata, S.; Iwasaki, M.; Ishii, Y. Inorg. Chem. 2004, 43, 6127−6129.
(d) Ikeda, Y.; Yamaguchi, Y.; Kanao, K.; Kimura, K.; Kamimura, S.;
Mutoh, Y.; Tanabe, Y.; Ishii, Y. J. Am. Chem. Soc. 2008, 130, 16856−
16857.
(8) For the vinylidene rearrangement of dialkyl- and diarylalkynes at
CpRu and CpFe complexes, see the following: (a) Mutoh, Y.; Ikeda,
Y.; Kimura, Y.; Ishii, Y. Chem. Lett. 2009, 38, 534−535. (b) Mutoh, Y.;
Imai, K.; Kimura, Y.; Ikeda, Y.; Ishii, Y. Organometallics 2011, 30, 204−
207. (c) Mutoh, Y.; Kimura, Y.; Ikeda, Y.; Tsuchida, N.; Takano, K.;
Ishii, Y. Organometallics 2012, 31, 5150−5158. For a DFT study on
the transformation, see the following: (d) Otsuka, M.; Tsuchida, N.;
Ikeda, Y.; Kimura, Y.; Mutoh, Y.; Ishii, Y.; Takano, K. J. Am. Chem. Soc.
2012, 134, 17746−17756.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We thank Professor Makoto Chikira (Chuo University) and Dr.
Tomoya Hirohama for the EPR measurement. This work was
supported by a Grant-in-Aid for Scientific Research (19028059,
20037060, 23105543) from the MEXT of Japan.
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