Synthesis and structural characterization of a series of new chiral-at-metal ruthenium allenylidene complexes

Article abstract of DOI:10.1002/ejic.201001176

New chiral-at-metal ruthenium indenyl PPh₃ phosphoramidite allenylidene complexes have been synthesized and structurally characterized. Through thermal ligand-exchange reactions with [RuCl(Ind)(PPh₃) ₂], the phosphoramidite ligands (R)-binol-N,N-dimethylphosphoramidite (5a), (R)-binol-N,N-dibenzylphosphoramidite (5b), (R,S)-binol-N-benzyl-N- α-methylbenzylphosphoramidite (5c), and (R)-catechol-2- methylpyrrolidinephosphoramidite [(R)-10] were converted into the complexes [RuCl(Ind)(PPh₃)(L)] [L = 5a, 79%; 5b, 87%; 5c, 80%, (R)-10, 67%]. The complexes [RuCl(Ind)(PPh₃)(5b)] and [RuCl(Ind)(PPh ₃)(5c)] were obtained diastereomerically pure and, by reaction with propargylic alcohols, subsequently converted into the allenylidene complexes [Ru(Ind)(PPh₃)(5b)(=C=C=CRR′)]⁺ PF₆ ^- (R = R′ = Ph, 85%; R = Ph, R′ = Me, 66%; R = 2-furyl, R′ = Me, 94%; R = R′ = 4-fluorophenyl, 76%; R = 4-methoxyphenyl, R′ = Me, 66%) and [Ru(Ind)(PPh₃)(5c)(=C=C=CRR′)] ⁺ PF₆^- (R = R′ = Ph, 91%; R = Ph, R′ = Me, 72%; R = 2-furyl, R′ = Me, 93%), which were also obtained diastereomerically pure. Complex [RuCl(Ind)(PPh₃)(5b)] and three of the new allenylidene complexes were characterized structurally, which showed that the chiral information was transferred from the precursor complex to the corresponding allenylidenes. Dynamic NMR experiments showed that during the synthesis of allenylidene complexes only one diastereomer was formed. The research presented herein has an impact on the chemistry of chiral allenylidene complexes as catalysts and as potential intermediates in propargylic substitution reactions. Chiral-at-metal ruthenium chloro indenyl phosphoramidite complexes have been converted into the corresponding allenylidene complexes, some of which have been structurally characterized. The chiral information was transferred from the chloro precursor complexes to the allenylidene complexes, which were obtained as optically pure diastereomers. Only one diastereomer was formed during the syntheses. Copyright

Full text of DOI:10.1002/ejic.201001176

FULL PAPER
DOI: 10.1002/ejic.201001176
Synthesis and Structural Characterization of a Series of New Chiral-at-Metal
Ruthenium Allenylidene Complexes
Stephen Costin,[a] Andria K. Widaman,[a] Nigam P. Rath,[a,b] and Eike B. Bauer*[a]
Keywords: P ligands / Ruthenium / Chirality
New chiral-at-metal ruthenium indenyl PPh3 phosphoramid-
ite allenylidene complexes have been synthesized and struc-
turally characterized. Through thermal ligand-exchange re-
actions with [RuCl(Ind)(PPh3)2], the phosphoramidite ligands
(R)-binol-N,N-dimethylphosphoramidite (5a), (R)-binol-N,N-
dibenzylphosphoramidite (5b), (R,S)-binol-N-benzyl-N-α-
85%; R = Ph, RЈ = Me, 66%; R = 2-furyl, RЈ = Me, 94%; R =
RЈ = 4-fluorophenyl, 76%; R = 4-methoxyphenyl, RЈ = Me,
–
66%) and [Ru(Ind)(PPh3)(5c)(=C=C=CRRЈ)]+ PF6 (R = RЈ =
Ph, 91%; R = Ph, RЈ = Me, 72%; R = 2-furyl, RЈ = Me, 93%),
which were also obtained diastereomerically pure. Complex
[RuCl(Ind)(PPh3)(5b)] and three of the new allenylidene com-
methylbenzylphosphoramidite (5c), and (R)-catechol-2- plexes were characterized structurally, which showed that
methylpyrrolidinephosphoramidite [(R)-10] were converted
into the complexes [RuCl(Ind)(PPh3)(L)] [L = 5a, 79%; 5b,
87%; 5c, 80%, (R)-10, 67%]. The complexes [RuCl(Ind)-
(PPh3)(5b)] and [RuCl(Ind)(PPh3)(5c)] were obtained dia-
stereomerically pure and, by reaction with propargylic
alcohols, subsequently converted into the allenylidene com-
the chiral information was transferred from the precursor
complex to the corresponding allenylidenes. Dynamic NMR
experiments showed that during the synthesis of allenylid-
ene complexes only one diastereomer was formed. The re-
search presented herein has an impact on the chemistry of
chiral allenylidene complexes as catalysts and as potential
intermediates in propargylic substitution reactions.
plexes [Ru(Ind)(PPh3)(5b)(=C=C=CRRЈ)]+ PF6 (R = RЈ = Ph,
–
Introduction
Allenylidene complexes are cumulene-type organometal-
lic architectures of the general formula [LnM=C=C=
CRRЈ].[1] Although known since the 1970s,[2] their system-
atic investigation was significantly advanced when Selegue
found in 1982 that allenylidene complexes 2 are readily ac-
cessible from propargylic alcohols 1 and an appropriate
precursor complex in the presence of MPF6 (Scheme 1).[3]
Since then, a variety of allenylidene complexes have been
synthesized and characterized. The majority of allenylidene
complexes are based on ruthenium,[4] but other metals have
been used as well, for example, Cr and W,[5a] Mo,[5b] Mn,[2b]
Re,[5c] Ir,[5d] Rh,[1f] Fe,[5e] Os,[5f,5g] Pd,[5h,5i] and Ni.[6]
Allenylidenes play an important dual role as catalysts and
intermediates in a number of catalytic transformations.[7]
Some ruthenium allenylidene complexes are efficient cata-
lyst precursors in ring-closing metathesis reactions,[8a–8d]
ring-opening metathesis polymerization,[8e,8f] and in the de-
hydrogenative dimerization of tin hydrides.[9] Calcula-
tions[10] as well as reactivity studies[11] have shown that the
Cα and Cγ atoms of the allenylidene chain are electrophilic,
Scheme 1. Allenylidene complex formation and reactivity.
whereas the Cβ atom is nucleophilic. Thus, the Cβ atom
can be protonated[11a] and the Cα and Cγ atoms react with
nucleophiles. Attack of the Cγ atom by monofunctional nu-
cleophiles leads to the alkynyl complex 3 (Scheme 1), which
delivers the substituted product 4 after protonolysis.[12]
Thus, the whole sequence in Scheme 1 represents a propar-
gylic substitution reaction via an allenylidene intermedi-
ate.[12] Nicholas described a multistep sequence for such
propargylic substitution reactions employing stoichiometric
amounts of toxic [Co2(CO)8] and involving cobalt-stabilized
propargylic cations as intermediates.[13] Stoichiometric
multistep alternatives following the path depicted in
Scheme 1 have been described in the literature.[4g] Di-
meric[14] and monomeric[15] ruthenium complexes have been
shown to catalyze propargylic substitution reactions with a
variety of carbon and heteroatom nucleophiles, for which
allenylidene complexes were suggested as intermediates.
Chiral ruthenium dimeric complexes [RuCl(Cp*)(μ-S*R)]2
[a] Department of Chemistry and Biochemistry, University of
Missouri – St. Louis,
1, University Boulevard, St. Louis, MO 63121, USA
E-mail: bauere@umsl.edu
[b] Center for Nanoscience, University of Missouri – St. Louis,
1, University Boulevard, St. Louis, MO 63121, USA
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201001176.
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S. Costin, A. K. Widaman, N. P. Rath, E. B. Bauer
FULL PAPER
(S*R = chiral thiolate) catalyze enantioselective substitu-
Complex 6 could be converted into the corresponding
tion and cyclization reactions with enantiomeric excesses allenylidene complex but analytically pure material could
between 68 and 99%.[16]
not be isolated. We thus started to investigate structurally
Chiral allenylidene complexes have been far less investi- related indenyl alternatives. Indenyl complexes show in-
gated than their achiral counterparts. In addition to the di- creased reactivity in ligand-exchange reactions[24] and as
meric chiral thiolate ruthenium complexes mentioned catalysts,[25] referred to in the literature as the “indenyl ef-
above, a chiral (R)-binap ruthenium indenyl allenylidene fect”.[26]
complex has been used in a multistep procedure (similar to
Herein, we describe a general, convenient, high-yielding
Scheme 1) to synthesize optically active γ-keto alkynes.[17a] route to optically pure chiral-at-metal allenylidene indenyl
In a related procedure, Gimeno and co-workers took ad- ruthenium complexes. These allenylidene complexes were
vantage of the chiral allenylidenes derived from chiral pro- obtained from the corresponding chiral-at-metal ruthenium
pargylic alcohols to prepare optically active alkynes by re- chloro complexes with chirality transfer and are the first
action with different nucleophiles.[4g,17b,17c] Aromatic π–π examples of allenylidene complexes with phosphoramidite
interactions in optically active ruthenium allenylidene com- ligands. A portion of this work has been communicated pre-
plexes have been reported to play an important role in viously.[27]
stereoselection in potential catalytic substitution reactions
involving allenylidene intermediates.[17d]
Results
Chiral-at-metal allenylidene complexes are rare. We are
aware of only two examples in the literature to date. Gi-
meno and co-workers synthesized a chiral-at-metal ruthe-
nium indenyl complex with an optically active diphenyl-
phosphane ferrocenyl oxazoline ligand, which was con-
verted into the corresponding allenylidene complex.[18a]
Similarly, Matsuo and co-workers synthesized and structur-
ally characterized a chiral-at-metal ruthenium fullerene cy-
clopentadienyl allenylidene complex with the chiral chelate
ligand 1,2-bis(diphenylphosphanyl)propane.[18b] In both
cases, the allenylidene complexes exhibit stereogenic centers
at both the metal and ligand, and were obtained with dia-
stereomeric purity. Some chiral-at-metal allenylidene com-
plexes synthesized from achiral starting materials are
known and have been isolated as racemic mixtures.[4k,4m]
We are interested in chiral-at-metal complexes[19] as it has
been shown that some of them are promising catalysts for
producing high enantiomeric excesses in a number of enan-
tioselective organic transformations.[20] We therefore set out
to advance the chemistry of chiral-at-metal allenylidene
complexes and began to search for a general systematic ap-
proach to this class of compound. The starting points of
our investigations were chiral-at-metal ruthenium chloro
phosphoramidite complexes. Phosphoramidites (5 in Fig-
ure 1) are a class of versatile monodendate ligands[21] that
are easy to synthesize and they have been increasingly used
as ligands in transition-metal-catalyzed organic transforma-
tions.[22] We have already synthesized the chiral-at-metal ru-
Ligand and Precursor Complex Syntheses
The majority of previously reported phosphoramidite li-
gands were derived from binol (see Figure 1). We were first
interested in determining whether a simpler and thus
cheaper diol could be employed in ligand and metal com-
plex synthesis. By employing standard literature pro-
cedures,[21] catechol (7) was converted into the chiral phos-
phoramidite (R)-10 by using the commercial (R)-2-methyl-
pyrrolidine (9) as the amine (Scheme 2). In a two-step, one-
pot procedure, the catechol was first converted into the cor-
responding phosphorochloridite 8, which was further pro-
cessed to the phosphoramidite (R)-10. The new ligand was
obtained as a yellow oil in 78% isolated yield after purifica-
tion by filtration and extraction.
Scheme 2. Phosphoramidite synthesis.
Our previously synthesized chiral-at-metal ruthenium cy-
thenium chloro cyclopentadienyl complex 6 (Figure 1) as a clopentadienyl phosphoramidite complex 6 (Figure 1) was
single optically pure diastereomer and employed it as a cat- obtained from the precursor complex [RuCl(Cp)(PPh3)2] by
alyst in the Mukaiyama aldol reaction.[23]
thermal PPh3 exchange.[23] To obtain the corresponding in-
denyl ruthenium complexes, we envisaged a similar ligand
exchange using the known[28] ruthenium complex [Ru-
Cl(Ind)(PPh3)2] (11, Ind = indenyl), which has previously
been successfully employed in similar ligand-exchange reac-
tions.[26e] Accordingly, the phosphoramidite ligands 5a–c
and (R)-10 were heated with 11 in toluene or THF for 1–
3 hours (Scheme 3). Chromatographic work-up afforded the
corresponding ruthenium complexes 12a–d as red-orange
powders in 67–87% isolated yields. The employment of tol-
uene in the synthesis of 12a and 12d was necessary as we
Figure 1. Phosphoramidites and a ruthenium complex thereof.
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New Chiral-at-Metal Ruthenium Allenylidene Complexes
Scheme 3. Synthesis of chiral-at-metal chloro phosphoramidite complexes 12.
could not remove THF, even by column chromatography. in energy. For complexes 12b and 12c bearing larger phos-
The new complexes are chiral at the metal and have been phoramidite ligands, only one set of NMR signals was ob-
characterized by NMR (1H, 13C, 31P), MS, IR, and, in most served in the crude material as well as after purification,
cases, by elemental analysis.
which suggests that only one diastereomer was formed. The
1
The coordination of one phosphoramidite and one PPh3 indenyl ligand gives very distinct H and 13C NMR signals
ligand is readily indicated by two distinct 31P NMR signals, for the three protons and five carbon atoms of its coordi-
2
which exhibit JPP couplings between 58.5 and 77.0 Hz, as nated five-membered ring.[26e] As a result of the stereogenic
expected for complexes with two different phosphorus centers at the metal and ligand, all these carbons and pro-
atoms in a metal coordination sphere. As deduced from the tons are diastereotopic and give individual signals in the
NMR spectroscopic data, complexes 12a and 12d were iso- corresponding NMR spectra.
lated as a mixture of diastereomers, whereas complexes 12b
To unequivocally establish the structures of the new ru-
and 12c were obtained as single optically pure dia- thenium complexes, the X-ray structure of complex 12b was
stereomers. The 31P NMR spectra of 12a and 12d showed determined (Tables 1 and 2, Figure 2). The structure closely
1
two sets of signals, and some signals in the H NMR were resembles that of the cyclopentadienyl analogue 6 (Fig-
doubled, revealing a diastereomeric ratio (dr) of 2:1 for 12a ure 1), which was structurally characterized previously.[23]
and 1:1 for 12d. We speculate that the smaller phosphor- To obtain information about the impact of the coordination
amidite ligands in 12a and 12d create only slight steric con- of phosphoramidite ligands on their structures, an X-ray
gestion at the metal, rendering the two diastereomers close determination of the ligand 5b was also performed (Tables 1
Table 1. Selected bond lengths and angles.
Bond lengths [Å][a]
5b
12b·
(CH2Cl2)
[15a][PF6]·
(CH2Cl2)
[15b][PF6]·
(CH2Cl2)2
[15d][PF6]
13
Ru1–P1
Ru1–P2
Ru1–Cl1
Ru1–C10
C10–C11
C11–C12
P1–N1
–
–
–
–
–
–
2.1961(7)
2.3504(8)
2.4439(7)
–
–
–
2.2730(6)
2.3131(7)
–
1.887(2)
1.250(4)
1.357(4)
1.644(2)
2.2729(5)
2.3037(5)
–
1.8937(19)
1.250(3)
1.348(3)
1.6467(17)
2.2680(8)
2.3217(9)
–
1.870(4)
1.256(6)
1.346(7)
1.654(3)
2.321(2)
2.358(2)
–
1.878(5)
1.260(7)
1.353(7)
–
1.648(3)
1.663(3)
Bond angles [°]
C10–Ru1–P1
C10–Ru1–P2
P1–Ru1–P2
C10–C11–C12
C11–C12–CX
–
–
–
–
–
89.28(3)[b]
86.99(3)[b]
98.87(3)
–
92.73(7)
85.82(7)
100.13(2)
177.6(3)
120.1(3)
(X = 13)
100.12(9)
110.33(11)
95.56(10)
92.39(6)
84.81(6)
100.416(17)
174.9(2)
120.76(19)
(X = 14)
99.76(7)
89.59(11)
85.31(13)
100.12(3)
174.8(5)
88.7(2)
97.4(2)
96.95(5)
168.2(7)
118.2(6)
124.8(8)
(X = 10)
100.46(13)
96.61(16)
109.05(14)
O1–P1–O2
O1–P1–N1
O2–P1–N1
97.37(10)
108.90(12)
96.48(11)
99.58(10)
108.61(12)
95.13(12)
–
–
–
96.36(8)
109.91(8)
Other geometrical parameters
Ru–Cp [Å][c]
–
–
1.909
–
0.0281
1.927
34.4
0.0108
1.931
14.8
0.0104
1.940
27.6
0.0045
1.951(5)
15.5(3)
–
Dihedral angle [°][d]
Deviation from planarity at nitrogen [Å][e] 0.0305
[a] C10–C11–C12 is C1–C2–C3 in complex 15d. [b] Cl1–Ru1–P1 and Cl1–Ru1–P2, respectively. [c] Distance between the centroid of Cp
of the indenyl ligand and the ruthenium center. [d] Angle between the planes defined by the Cp centroid, Ru, C10 and C10–C11–C12–
C13 (15a,b) and C1–C2–C3–C4 (15d), respectively. [e] Average deviation from a least-squares mean plane defined by N1, P1 and C21,
C28 (5b), C30, C37 (12b), C25, C32 (15a), C38, C45 (15b), and C45, C52 (15d) [see Equation (1)].
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Figure 2. Molecular structures of 5b (left) and 12b (right). Ellipsoids are shown at the 30% probability level. Hydrogen atoms and solvent
molecules have been omitted for clarity. For key bond lengths and bond angles, see Table 1.
and 2, Figure 2). The structure features a planar geometry sis of the related allenylidene complex [Ru(Ind)(PPh3)2-
at the nitrogen atom, which has been observed before in the (=C=C=CPh2)]+[PF6]– (13).[4l] However, the use of NaPF6
X-ray structure of the phosphoramidite ligand 5c.[29] De- in MeOH at reflux[4l] with complex 12b and propargylic
tails are discussed below together as are the other structures alcohol 14a resulted in a sluggish reaction generating a 1:1
obtained for this study.
mixture of diastereomers, as revealed by NMR (1H, 31P).
When AgPF6 in CH2Cl2 was used for chloride abstraction
followed by filtration to remove AgCl, the corresponding
allenylidene complex was obtained with diastereomeric pu-
Allenylidene Complex Synthesis
As only 12b and 12c were obtained with diastereomeric rity. However, we found that the chloride scavenger (Et3O)-
purity, they were employed in allenylidene complex synthe- PF6 can also be used for activation of the precursor com-
sis under the conditions previously described for the synthe- plexes 12b and 12c. By using (Et3O)PF6 for chloride ab-
Scheme 4. Synthesis of allenylidene complexes.
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New Chiral-at-Metal Ruthenium Allenylidene Complexes
straction, the removal of MCl was not necessary, facilitating 15a,b,d are identical. The chloro ligand is replaced by the
the work-up.
allenylidene chain with overall retention of the absolute
Accordingly, a CH2Cl2 solution of complex 12b was first
treated at 0 °C with 1 equiv. of (Et3O)PF6, which resulted
in a slight darkening of the solution (Scheme 4). The corre-
sponding propargylic alcohol 14 was subsequently added,
which resulted in a quick color change from red to dark
purple. After removal of all the volatiles and washing with
Et2O, the novel phosphoramidite complexes [15a–e]+ were
isolated as their PF6– salts as intensely colored purple pow-
ders in 66–94% isolated yields. These complexes will sub-
sequently be referred to without charges and counterions.
The new allenylidene complexes 15 were characterized by
NMR (1H, 13C, 31P), MS, IR, and elemental analysis. Their
formation was best demonstrated by the characteristic sig-
nals in the IR and 13C NMR spectra. As generally observed
for allenylidene complexes,[1f] the carbon atoms of the allen-
ylidene chain give distinct resonances of low intensity in the
13C NMR spectra for the Cα (293.8–299.4 ppm), Cβ (185.2–
199.7 ppm), and Cγ (159.9–162.8 ppm) carbons. The Cα res-
onance appears as a doublet, a doublet of doublets (JCP
=
20.8–23.6 Hz), or a multiplet due to C–P couplings. The
resonances for Cβ in 15b also show JCP coupling (13.8 Hz).
Furthermore, the new complexes give an intense band for
the allenylidene chain in the IR spectra between 1935 and
1949 cm–1, which is also indicative of this class of complex-
es.[1f]
In the 31P NMR spectra, the signals arising from the
PPh3 and phosphoramidite ligands in 15 are slightly shifted
relative to those of the corresponding starting materials.
Most significantly, only one set of signals was observed in
all the NMR spectra of both crude and isolated material,
which suggests that only one diastereomer was formed. No
1
vinylic resonances were observed in the H NMR spectra
of 15b,c,e, which suggests that no vinylvinylidene isomers
were present in the isolated material and thus no isomeriza-
tion took place, as sometimes reported when Selegue’s pro-
tocol is applied to allenylidene synthesis (see below).[1a,30]
The allenylidene complexes 15 are air-stable powders; com-
plex 15c is somewhat hygroscopic and was isolated as a hy-
1
drate, as shown by H NMR, IR, and elemental analysis.
To unequivocally establish the structures and configura-
tions of the novel allenylidene complexes, the X-ray struc-
tures of complexes 15a,b,d were determined (Tables 1 and 2,
Figure 3). The solid-state structures show that the absolute
Figure 3. Molecular Structures of 15a (top), 15b (middle), and 15d
(bottom). Ellipsoids are shown at the 30% probability level. Hydro-
gen atoms and solvent molecules have been omitted for clarity. For
configurations about the ruthenium center in 12b and key bond lengths and angles, see Table 1.
Scheme 5. Synthesis of less stable allenylidene complexes.
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S. Costin, A. K. Widaman, N. P. Rath, E. B. Bauer
FULL PAPER
configuration and the chiral information has been transfer- solution. A second set of doublets appears, which might be
red from the starting material 12b to the products 15a,b,d. due to a second diastereomer formed in solution (at +25 °C,
The structures will be discussed in more detail in the next only two very broad peaks at around 175 and 45 ppm were
section.
observed, see the Supporting Information). Upon addition
The precursor complex 12c could also be converted into of the propargylic alcohol, only one set of signals for the
the corresponding allenylidene complexes by using the same product was observed in the 31P NMR spectrum (Figure 4,
protocol as employed for the synthesis of complexes 15 bottom). These spectra show that only one of the two pos-
(Scheme 5). The resulting allenylidene complexes 16a–c sible diastereomers of the allenylidene complex forms dur-
were isolated in 72–93% yields with approximately 90% ing the reaction.
spectroscopic purity, but attempts at purification resulted in
ongoing decomposition. The NMR, IR, and MS charac-
terization data (which are given in the Supporting Infor-
mation) are similar to those of complexes 15 and clearly
show the formation of allenylidene complexes in dia-
stereopure form. However, complexes 16b and 16c decom-
posed within hours in CDCl3, as can be seen by the appear-
ance of extra peaks in the 13C NMR spectra. Complexes 16
appear to be hygroscopic as the presence of water is ob-
1
served in the H NMR spectra and elemental analyses. We
hypothesize that the extra methyl group on the carbon atom
in the position α to the nitrogen creates significant steric
congestion about the ruthenium center, which destabilizes
the corresponding complexes leading to PPh3 dissociation.
Further Experiments Related to the Stereochemistry of the
New Complexes
The chloro precursor complexes 12b and 12c and all the
allenylidene complexes 15 and 16 were obtained as enantio-
pure single diastereomers. NMR evidence of a second dia-
stereomer was not observed for any of the precursors or
allenylidene complexes. To obtain further information
about the configurational stability of the complexes as well
as the diastereoselective formation of the allenylidenes, dy-
namic NMR experiments were performed with the chloro
precursor 12b and allenylidene complex 15a.
Both complexes 12b and 15a showed configurational sta-
bility between –50 and +25 °C, as indicated by their 1H and
Figure 4. 31P NMR spectra recorded at –30 °C for different steps
in allenylidene formation. Top: starting complex 12b. Middle: spec-
31P NMR spectra (see the Supporting Information), which
exhibit only minor line-broadening at different tempera-
tures. The precursor complex 12b is configurationally stable
up to 60 °C, whereas the allenylidene complexes 15 and 16
show significant decomposition at elevated temperatures.
To obtain information about the diastereoselective for-
mation of the allenylidene complexes, a dynamic NMR ex-
trum recorded immediately after the addition of (Et3O)PF6. Bot-
tom: spectrum recorded immediately after the addition of propar-
gylic alcohol 14a.
A potential second diastereomer could result from an ex-
periment was performed. A sample of the chloro precursor change of the two phosphorus-based ligands to give a mix-
1
complex 12b was first treated with (Et3O)PF6 and H and ture of 17a and 17b (Scheme 6). Assuming a dynamic pro-
31P NMR spectra were recorded at different temperatures. cess at the metal, species 17a in Scheme 6 must react with
Subsequently, the propargylic alcohol 14a was added to the the propargylic alcohol much faster than species 17b to pro-
1
same sample, and again H and 31P NMR spectra were re- duce the observed diastereoselectivity. However, it has been
corded. All the NMR spectra are given in the Supporting reported in the literature that extra signals in the NMR
Information and Figure 4 shows the three 31P NMR spectra spectra of the corresponding complexes may appear at low
recorded at –30 °C.
temperatures due to slowing of dynamic processes centered
It appears that abstraction of the chloride from the pre- on the ligands.[19b] In the free ligand 5c, dynamic NMR
cursor complex 12b (Figure 4, top) results in a species 17 experiments have shown that rotation around the P–N bond
(Figure 4, middle), which shows some dynamic behavior in is frozen at –70 °C.[29]
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New Chiral-at-Metal Ruthenium Allenylidene Complexes
chain. We also did not observe allenylidene-to-indenylidene
rearrangements,[31] which would also increase steric demand
about the ruthenium center.
X-ray Crystallography
The X-ray analyses of 12b and 15a,b,d confirm the pro-
posed piano-stool structures of the complexes. Key bond
lengths and angles are compiled in Table 1 and, for com-
parison, the corresponding values for the structurally re-
lated complex [Ru(Ind)(PPh3)2(=C=C=CPh2)]PF6 (13) are
also listed.[4l] The bond angles about the ruthenium center
range from 84.81(6) to 92.73(7)°. The structures are thus
best described as slightly distorted octahedra. In all three
complexes, the Ru–P bond lengths for the phosphoramidite
ligands are shorter than those for the PPh3 ligands, with
Ru–P1 ranging from 2.1961(7) to 2.2730(6) Å compared
with the Ru–P2 bond lengths of 2.3037(5) to 2.3504(8) Å,
respectively. We observed this phenomenon previously in
the X-ray structures of complexes of 6 (Figure 1).[23] As a
result of the oxygen atoms bonded to the phosphorus, the
phosphoramidite ligands might be somewhat more π-acidic
than PPh3. This could result in a higher degree of metal-to-
ligand back-bonding, which would shorten the Ru–P bond.
As reported for ligand 5c,[29] ligand 5b features an almost
planar nitrogen atom, as seen by the calculated average de-
viation from planarity involving the nitrogen and the two
carbon and one phosphorus atom bonded to it [Table 1 and
Equation (1)]. We ascribed the planarity tentatively to a
partial double-bond character of the P–N bond. Interest-
ingly, the free ligand deviates from planarity slightly more
(0.0305 Å) than the coordinated ligand (0.0045–0.0281 Å).
Upon coordination of the phosphoramidite ligand, reso-
nance structure 21 in Equation (1) may contribute signifi-
cantly to the various resonance structures of ligand 5b, in-
creasing the double-bond character of the P–N bond and
hence the planarity about the nitrogen atom.
Scheme 6. NMR tube experiment. The square denotes an open co-
ordination site.
Discussion
Scope of the Reaction
This report describes the synthesis and structural charac-
terization of the first ruthenium phosphoramidite allenylid-
ene complexes. The new complexes are chiral at the metal
and were obtained from the corresponding chloro precur-
sors with chirality transfer, as determined by the X-ray
structures of the complexes 12b and 15a,b,d. Both electron-
rich (14e) and electron-poor (14d) propargylic alcohols
bearing either two aryl groups (14a,d) or one aryl and one
alkyl group (14b,c,e) could be employed in the synthesis of
the complexes (Scheme 4). Purely aliphatic propargylic
alcohols failed to be converted into the corresponding all-
enylidenes, which is in accord with the general observation
in the literature that aliphatic allenylidene complexes are
less stable than those bearing at least one aryl substituent
at the γ carbon.[1] Interestingly, we did not observe any vin-
ylvinylidene species, which often form when a propargylic
alcohol with α protons on the γ substituent are employed
(Scheme 7).[30] In that case, dehydration of the intermediate
18 can, in addition to the allenylidene complex, give the
corresponding vinylvinylidene species 19. We hypothesize
that for steric reasons, the formation of the bent vinylvinyl-
idene chain in 19 is disfavored. The coordination sphere
about the ruthenium center in the allenylidene complexes
15 is very congested and a bent vinylvinylidene chain is
sterically more demanding than a straight allenylidene
(1)
There are slight structural differences between the allen-
ylidene complexes 15a,b,d and 13, which mainly concern
the geometry about the ruthenium center. The P1–Ru–P2
bond angles for 15a,b,d are about 3° larger than for 13, as
expected for the bulkier phosphoramidite ligands. The bond
lengths about the ruthenium center for the phosphoramid-
ite complexes 15a and 15b are slightly smaller than for 13,
which could be associated with greater π-acidity of the
phosphoramidite ligands.
The C10–C11–C12 angles of the allenylidene chain in
15a,b,d are 177.6(3), 174.9(2), and 174.8(5)°, respectively.
This slight deviation from the ideal angle of 180° has fre-
quently been observed for other allenylidene complexes.[1]
The angles between C11, C12, and the ipso atom of the
Scheme 7. Potential vinylvinylidene formation.
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S. Costin, A. K. Widaman, N. P. Rath, E. B. Bauer
FULL PAPER
substituent at C12 are between 120.1(3) and 124.8(8)°, uent points downwards relative to the indenyl ligand. It has
which confirms the sp2 hybridization of the Cγ atom of the previously been suggested that the Cγ substituents are
allenylidene chain. The C=C bonds of the allenylidene aligned in such a way as to maximize the overlap between
chain are not of equal length in the three complexes. The the d π HOMO of the metal and the p π LUMO of the
internal Cα=Cβ bond is significantly shorter [1.250(3)– allenylidene chain, allowing for maximized metal-to-ligand
1.256(6) Å] than the terminal Cβ=Cγ bond [1.346(7)– back-donation.[1a,32]
1.357(4) Å]. Such bond differences are frequently observed
As can be seen in the schematic representation D in Fig-
in allenylidene complexes[1a] and they can be explained by ure 5, the allenylidene chain is flanked by the phosphoram-
the resonance contributor B, which exhibits an internal tri- idite ligand to the left and the PPh3 ligand to the right.
ple bond and results in a significantly shorter bond length Nucleophilic attack on the Cγ carbon as shown in Scheme 1
in the X-ray analysis; see Equation (2).
can either take place from the left or the right side in D and
as consequence of the chirality at the metal the two faces
are inequivalent. Figure 6 shows selected atoms of the X-
ray structure of 15b. It shows that one side of Cγ is shielded
by the phosphoramidite ligand much more efficiently than
the other side is shielded by the PPh3 ligand. The distance
of the Cγ carbon atom to the centroid of the closest phenyl
ring of the PPh3 ligand is 4.97 Å (dotted line in Figure 6,
calculated with the Mercury 1.4.2 software[40]), whereas it
is 3.80 Å for the centroid of the closest phenyl ring of the
phosphoramidite ligand. This difference potentially allows
for stereodifferentiation upon attack of the Cγ atom by a
nucleophile. Stoichiometric and catalytic experiments to
take advantage of this situation in propargylic substitution
reactions (as exemplified in Scheme 1) are currently un-
derway.
(2)
The position of the indenyl ligand relative to the other
three ligands in the solid-state structures is schematically
shown in Figure 5. As can be seen in C, for the chloro com-
plex 12b the aryl ring of the indenyl ligand occupies the
interstitial site between the chloro and the PPh3 ligands.
This conformation might be ascribed to steric factors as it
is the largest of the three potential interstitial sites. How-
ever, in the corresponding allenylidene complexes 15a and
15b, the position of the three ligands relative to the indenyl
ring has changed. Now, the aryl ring of the indenyl ligand
is oriented along the allenylidene chain, represented as D in
Figure 5. The same orientation was observed in the struc-
turally related complex 13.[4l] This orientation might have
an impact on the potential attack of nucleophiles as the
electrophilic Cα carbon atom is sterically much more pro-
tected than the Cγ carbon.
Figure 6. Shielding of the Cγ carbon atom by the ligands.
Figure 5. Schematic representation of the conformations of the
chloro and allenylidene complexes.
The positions of the two substituents at the Cγ carbon
atom in the allenylidene complexes (two aryls in 15a and
one phenyl and one methyl in 15b) is schematically repre-
sented by E (Figure 5). The substituents are oriented almost
Conclusions
We have synthesized the first ruthenium allenylidene
in a plane with an axis formed by the Cα atom of the alleny- complexes bearing chiral phosphoramidite ligands in the
lidene chain, the ruthenium center, and the cyclopen- coordination sphere. The new allenylidene complexes are
tadienyl centroid of the indenyl ligand. However, some devi- chiral at the metal and were obtained as optically pure sin-
ation from this planar alignment was observed, which has gle diastereomers from the corresponding chloro precursor
also been described for complex 13.[4l] This deviation can complexes. The chloro ligand was replaced with the allenyl-
be quantified by the angle between the planes defined by idene chain with complete transfer of chirality. The results
the Cp centroid, Ru, and C10 and C10–C11–C12–C13 or presented herein may have an impact on the catalytic appli-
C1–C2–C3–C4 (dihedral angle in Table 1)[4l] and is 34.4° for cations of allenylidene complexes both as chiral catalysts
15a, 14.8° for 15b, 27.6° for 15d, and 15.5(3)° for 13. For and chiral reactive intermediates in propargylic substitution
15b, the phenyl ring points upwards and the methyl substit- reactions. Corresponding studies are underway.
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New Chiral-at-Metal Ruthenium Allenylidene Complexes
give 12a as an orange solid in a 2:1 diastereomeric mixture (0.195 g,
0.223 mmol, 79%); m.p. 148–149 °C (dec., capillary). 1H NMR
(300 MHz, CDCl3, 25 °C):[36] δ = 7.90–7.66 (m, 6 H, arom.), 7.52
Experimental Section
General Methods: Chemicals were treated as follows: THF, toluene,
and diethyl ether (Et2O) were distilled from Na/benzophenone,
CH2Cl2 was distilled from CaH2. (R)-1,1Ј-Binaphthyl-2,2Ј-diol
[(R)-binol] (Strem), catechol (Fisher), phosphorus trichloride
(PCl3), N-methyl-2-pyrrolidinone (Acros), (R)-2-methylpyrrolidine
(Aldrich), 1,1-diphenyl-2-propyn-1-ol (Aldrich), 2-phenyl-3-butyn-
2-ol (Aldrich), (Et3O)PF6 (Aldrich), Celite® (Aldrich), tert-butyl
methyl ether (Aldrich), and other materials were used as received.
(R)-binol-N,N-dimethylphosphoramidite (5a),[21a] (R)-binol-N,N-
dibenzylphosphoramidite (5b),[21c] (R,S)-binol-N-benzyl-N-α-meth-
ylbenzylphosphoramidite (5c),[33] 2-(2-furyl)-3-butyn-2-ol (14c),[34]
bis(4-fluorophenyl)-3-propyn-2-ol (14d),[35a] 2-(4-methoxyphenyl)-
3-butyn-2-ol (14e),[35b] and [RuCl(Ind)(PPh3)2] (11)[28] were synthe-
sized according to literature procedures.
3
(d, JHH = 4.3 Hz, 2 H, arom.), 7.45–7.08 (m, 18 H, arom.), 7.06–
3
6.95 (m, 5 H, arom.), 6.92–6.80 (m, 14 H, arom.), 6.73 (t, JHH
=
7.2 Hz, 1 H, arom.), 6.55 (d, 3JHH = 8.3 Hz, 1 H, arom.), 5.47–5.40
(m, 1 H, indenyl), 5.28 (br. s, 1 H, indenyl), 4.97 (br. s, 0.5 H,
indenyl*), 4.63 (br. s, 0.5 H, indenyl*), 4.18 (br. s, 1 H, indenyl),
3.71 (br. s, 0.5 H, indenyl*), 2.47 (s, 3 H, CH3), 2.43 (s, 3 H, CH3Ј),
1.92 (br. s, 1.5 H, CH3*), 1.89 (br. s, 1.5 H, CH3Ј*) ppm. 13C{1H}
NMR (75 MHz, CDCl3, 25 °C; major diastereomer):[37] δ = 153.2
(s, arom.), 150.9 (d, JCP = 14.7 Hz, arom.), 149.6 (d, JCP = 8.0 Hz,
arom.), 136.7 (s, arom.), 136.1 (s, arom.), 134.6 (d, JCP = 10.5 Hz,
arom.), 134.2 (d, JCP = 10.0 Hz, arom.), 133.4 (s, arom.), 133.1 (s,
arom.), 131.3 (s, arom.), 131.2 (d, JCP = 3.7 Hz, arom.), 130.2 (s,
arom.), 129.8 (s, arom.), 129.4 (br. s, arom.), 128.8 (s, arom.), 128.6
(d, JCP = 3.3 Hz, arom.), 128.4 (s, arom.), 128.3 (s, arom.), 128.2
(s, arom.), 128.1 (s, arom.), 127.8 (s, arom.), 127.7 (s, arom.), 127.6
(s, arom.), 127.4 (s, arom.), 127.2 (s, arom.), 127.1 (s, arom.), 126.2
(s, arom.), 126.0 (s, arom.), 125.2 (d, JCP = 4.2 Hz, arom.), 125.0
(s, arom.), 124.8 (s, arom.), 124.0 (s, arom.), 123.9 (s, arom.), 123.0
(d, JCP = 3.3 Hz, arom.), 122.0 (s, arom.), 118.3 (s, arom.), 113.0
(d, JCP = 5.5 Hz, indenyl), 112.2 (d, JCP = 5.9 Hz, indenyl), 91.4
(s, indenyl), 66.9 (d, JCP = 9.7 Hz, indenyl), 63.3 (s, indenyl), 39.5
NMR spectra were recorded at room temperature with a Bruker
Avance 300 MHz or Varian Unity Plus 300 MHz instrument and
referenced to a residual solvent signal. All assignments are tenta-
tive. Exact masses were obtained with a JEOL MStation [JMS-700]
mass spectrometer. Melting points were measured with an Electro-
thermal 9100 instrument. IR spectra were recorded with a Thermo
Nicolet 360 FT-IR spectrometer. Elemental analyses were per-
formed by Atlantic Microlab Inc., Norcross, GA, USA.
(s, CH3), 39.4 (CH3Ј) ppm. 31P{1H} NMR (121 MHz, CDCl3,
2
25 °C): δ = 177.5 (br. s, phosphoramidite*), 176.3 (d, JPP
=
=
(R)-Catechol-2-methylpyrrolidine-phosphoramidite [(R)-10]: Phos-
phorus trichloride (PCl3; 2.0 mL, 23 mmol) was added to a Schlenk
flask containing catechol (0.402 g, 3.65 mmol) followed by N-
methyl-2-pyrrolidinone (0.01 mL, 0.1 mmol). The resulting slurry
was heated at reflux for 30 min. Excess PCl3 was removed under
oil-pump vacuum to yield a yellow liquid. Et2O (5.0 mL) was added
and removed under vacuum twice to remove remaining PCl3. The
liquid was dissolved in THF (12 mL) and triethylamine was added
(0.83 mL, 6.3 mmol) followed by (R)-2-methylpyrrolidine (0.32 mL,
3.2 mmol). After stirring for 1 h at room temperature, the resulting
slurry was filtered through Celite® and the solvent removed under
vacuum. The yellow liquid was dissolved in CH2Cl2 (30 mL) and
extracted with saturated aq. NaHCO3 (2ϫ30 mL). The organic
layer was dried with Na2SO4, filtered, and the volatiles removed
under oil-pump vacuum to yield (R)-10 as a yellow oil (0.569 g,
2
65.1 Hz, phosphoramidite), 52.1 (br. s, PPh3*), 49.2 (d, JPP
65.1 Hz, PPh ) ppm. IR (neat solid): ν = 3047 (w), 2917 (w), 1586
˜
3
(w), 1432 (m), 1223 (m), 945 (m), 693 (m) cm–1. HRMS: calcd. for
C49H40NO2P235Cl102Ru 873.1265; found 873.1284.
[RuCl(Ind)(PPh3)(5b)] (12b): THF (8 mL) was added to a Schlenk
flask containing [RuCl(Ind)(PPh3)2] (11; 0.303 g, 0.390 mmol) and
phosphoramidite 5b (0.200 g, 0.391 mmol) and the solids dissolved.
The red solution was heated at reflux in an oil bath for 1 h. The
solvent was removed under vacuum and the resulting solid was
purified by flash chromatography employing a 2.5ϫ15 cm silica
column. The remaining ligand and PPh3 were eluted with CH2Cl2
and then the complex was eluted with CH2Cl2/Et2O (99:1, v/v),
collecting the red band. The solvent was removed under vacuum
to give 12b as a single diastereomer (0.347 g, 0.338 mmol, 87%);
m.p. 176–177 °C (dec., capillary). 1H NMR (300 MHz, CDCl3,
1
2.55 mmol, 78%). H NMR (300 MHz, CDCl3, 25 °C): δ = 6.92–
6.84 (m, 2 H, Ph), 6.82–6.75 (m, 2 H, Ph), 3.79–3.63 (m, 1 H,
NCHCH3), 2.92–2.73 (m, 2 H, NCH2), 1.90–1.78 (m, 1 H, CHHЈ),
3
3
25 °C): δ = 8.11 (t, JHH = 8.3 Hz, 2 H, arom.), 7.70 (d, JHH
=
3
8.1 Hz, 1 H, arom.), 7.62 (d, JHH = 8.4 Hz, 1 H, arom.), 7.54 (t,
3
1.77–1.52 (m, 2 H, CH2), 1.41–1.29 (m, 1 H, CHHЈ), 1.11 (d, JHH
3JHH = 7.1 Hz, 1 H, arom.), 7.52–7.44 (m, 2 H, arom.), 7.35–7.20
= 6.4 Hz, 3 H, CH3) ppm. 13C{1H} NMR (75 MHz, CDCl3,
3
(m, 14 H, arom.), 7.15–6.84 (m, 12 H, arom.), 6.75 (d, JHH
=
2
2
25 °C): δ = 146.8 (d, JCP = 8.1 Hz, CO), 146.6 (d, JCP = 8.1 Hz,
8.8 Hz, 3 H, arom.), 6.50–6.35 (m, 5 H, arom.), 5.71 (br. s, 1 H,
2
CЈO), 122.0 (s, Ph), 111.5 (s, Ph), 54.5 (d, JCP = 22.2 Hz, NCH),
2
indenyl), 5.36 (br. s, 1 H, indenyl), 5.00 (d, JHH = 10.6 Hz, 1 H,
2
3
44.3 (d, JCP = 4.1 Hz, NCH2), 34.6 (d, JCP = 3.5 Hz, CH2), 24.9
2
NCHHЈ), 4.95 (d, JHH = 10.6 Hz, 1 H, NCHHЈ), 4.05 (br. s, 1 H,
3
3
(d, JCP = 1.6 Hz, CH2), 24.0 (d, JCP = 8.3 Hz, CH3) ppm.
2
2
indenyl), 3.54 (d, JHH = 15.1 Hz, 1 H, NCHHЈ), 3.49 (d, JHH
= 15.1 Hz, 1 H, NCHHЈ) ppm. 13C{1H} NMR (75 MHz, CDCl3,
25 °C): δ = 151.3 (s, arom.), 151.1 (s, arom.), 149.2 (s, arom.), 148.5
(s, arom.), 139.4 (s, arom.), 134.3 (br. s, arom.), 133.8 (s, arom.),
132.7 (s, arom.), 131.5 (s, arom.), 131.1 (s, arom.), 130.2 (s, arom.),
130.0 (s, arom.), 129.5 (s, arom.), 128.6 (s, arom.), 128.4 (s, arom.),
127.2 (s, arom.), 126.2 (s, arom.), 125.8 (s, arom.), 125.5 (s, arom.),
125.0 (s, arom.), 124.4 (s, arom.), 123.3 (s, arom.), 122.8 (s, arom.),
122.0 (s, arom.), 121.4 (s, arom.), 113.6–113.5 (m, indenyl), 111.8–
31P{1H} NMR (121 MHz, CDCl3, 25 °C): δ = 145.0 (s) ppm. IR
(neat solid): ν = 3061 (m), 2966 (s), 2871 (s), 1604 (m), 1483 (s),
˜
1335 (s), 1240 (s), 859 (s), 745 (s) cm–1. HRMS: calcd. for
C11H14NO2P 223.0762; found 223.0755. C11H14NO2P (223.21):
calcd. C 59.19, H 6.32; found C 58.90, H 6.31.
[RuCl(Ind)(PPh3)(5a)] (12a): Toluene (5 mL) was added to a
Schlenk flask containing [RuCl(Ind)(PPh3)2] (11; 0.218 g,
0.281 mmol) and phosphoramidite 5a (0.101 g, 0.281 mmol) and
the mixture was heated at 65 °C in an oil bath for 2 h. The solvent
was removed under vacuum and the resulting solid was purified by
flash chromatography employing a 2ϫ15 cm silica column. The
remaining ligand and PPh3 were eluted with CH2Cl2 and then the
2
111.7 (m, indenyl), 90.4 (s, indenyl), 67.1 (d, JCP = 10.8 Hz, in-
denyl), 62.0 (s, indenyl), 50.6 (s, NCH2), 50.5 (s, NCH2) ppm.
2
31P{1H} NMR (121 MHz, CDCl3, 25 °C): δ = 172.8 (d, JPP
=
58.5 Hz, phosphoramidite), 46.8 (d, 2JPP = 58.5 Hz, PPh3) ppm. IR
complex was eluted with CH2Cl2/tert-butyl methyl ether (9:1, v/v), (neat solid): ν = 3050 (w), 1586 (w), 1223 (m), 940 (m), 741 (m),
˜
collecting the red band. The solvent was removed under vacuum to
692 (m) cm–1. HRMS: calcd. for C61H48ClNO2P235102Ru
Eur. J. Inorg. Chem. 2011, 1269–1282
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1277

S. Costin, A. K. Widaman, N. P. Rath, E. B. Bauer
FULL PAPER
1025.1892; found 1025.1924. C61H48ClNO2P2Ru (1025.51): calcd.
C 71.44, H 4.72; found C 71.44, H 4.66.
3
3
0.96 (d, JHH = 6.4 Hz, 3 H, CH3), 0.81 (d, JHH = 6.4 Hz, 3 H,
CH3*) ppm. 13C{1H} NMR (75 MHz, CDCl3, 25 °C): δ = 148.2 (d,
JCP = 5.6 Hz, arom.), 147.6 (d, JCP = 6.9 Hz, arom.), 147.0 (d, JCP
= 5.0 Hz, arom.), 146.1 (d, JCP = 5.6 Hz, arom.), 136.8 (s, arom.),
[RuCl(Ind)(PPh3)(5c)] (12c): THF (10 mL) was added to a Schlenk
flask containing [RuCl(Ind)(PPh3)2] (11; 0.442 g, 0.569 mmol) and
phosphoramidite 5c (0.299 g, 0.570 mmol) and the solids dissolved.
The red solution was heated at reflux for 3 h. The solvent was re-
moved under vacuum and the resulting solid was purified by flash
chromatography employing a 2ϫ16 cm silica column. The remain-
ing ligand and PPh3 were eluted with CH2Cl2 and then the complex
was eluted with CH2Cl2/Et2O (99:1, v/v), collecting the red band.
The solvent was removed under vacuum to give 12c as a single
diastereomer (0.471 g, 0.453 mmol, 80%); m.p. 162–164 °C (dec.,
136.5 (s, arom.), 136.1 (s, arom.), 135.9 (s, arom.), 134.2 (d, JCP
2.7 Hz, arom.), 134.1 (d, JCP = 2.1 Hz, arom.), 129.5 (d, JCP
=
=
2.2 Hz, arom.), 129.4 (d, JCP = 2.2 Hz, arom.), 128.4 (s, arom.),
128.3 (s, arom.), 127.7 (d, JCP = 7.1 Hz, arom.), 127.6 (d, JCP
=
6.7 Hz, arom.), 127.2 (s, arom.), 126.5 (d, JCP = 5.2 Hz, arom.),
125.7 (s, arom.), 123.9 (s, arom.), 121.3 (d, JCP = 4.0 Hz, arom.),
121.0 (d, JCP = 2.0 Hz, arom.), 115.2 (d, JCP = 3.8 Hz, indenyl),
114.1 (br. s, indenyl), 111.3 (d, JCP = 7.7 Hz, indenyl*), 110.9 (d,
JCP = 7.0 Hz, indenyl*), 110.7 (d, JCP = 4.5 Hz, arom.), 109.9 (d,
JCP = 7.7 Hz, arom.), 109.7 (d, JCP = 7.0 Hz, arom.), 108.4 (br. s,
arom.), 91.4 (s, indenyl), 90.7 (s, indenyl*), 69.8 (d, JCP = 14.3 Hz,
indenyl), 68.4 (d, JCP = 8.5 Hz, indenyl), 66.7 (d, JCP = 5.9 Hz,
indenyl*), 64.3 (d, JCP = 2.6 Hz, indenyl*), 54.8 (s, NCH), 54.4 (s,
NCH*), 47.2 (d, JCP = 10.7 Hz, NCH2), 47.0 (d, JCP = 9.2 Hz,
NCH2*), 34.7 (d, JCP = 3.8 Hz, CH2), 34.5 (d, JCP = 4.9 Hz, CH2*),
25.4 (d, JCP = 5.8 Hz, CH2), 25.1 (d, JCP = 6.0 Hz, CH2*), 23.1
(br. s, CH3), 22.7 (br. s, CH3*) ppm. 31P{1H} NMR (121 MHz,
1
3
capillary). H NMR (300 MHz, CDCl3, 25 °C): δ = 7.98 (d, JHH
3
= 8.9 Hz, 2 H, arom.), 7.62–7.55 (m, 4 H, arom.), 7.43 (t, JHH
7.2 Hz, 1 H, arom.), 7.35–7.29 (m, 5 H, arom.), 7.27–7.25 (m, 2 H,
arom.), 7.20–7.01 (m, 9 H, arom.), 7.00–6.85 (m, 7 H, arom.), 6.80–
=
3
6.72 (m, 4 H, arom.), 6.62–6.58 (br. m, 2 H, arom.), 6.44 (d, JHH
= 8.9 Hz, 1 H, arom.), 6.33–6.22 (br. m, 4 H, arom.), 6.19 (d, 3JHH
= 8.4 Hz, 1 H, arom.), 5.81–5.79 (m, 1 H, indenyl), 5.57 (br. s, 1
H, indenyl), 3.98 (br. s, 1 H, indenyl), 3.90–3.81 (m, 1 H, CHHЈ),
3
3.22–3.13 (m, 1 H, CHHЈ), 1.07 (d, JHH = 7.2 Hz, 3 H,
2
CDCl3, 25 °C): δ = 180.2 (d, JPP = 77.0 Hz, phosphoramidite),
CH3) ppm.[38] 13C{1H} NMR (75 MHz, CDCl3, 25 °C): δ = 151.4
(s, arom.), 151.2 (s, arom.), 143.2 (d, JCP = 8.1 Hz, arom.), 142.8
(s, arom.), 137.9 (s, arom.), 137.5 (s, arom.), 137.4 (s, arom.), 137.0
(s, arom.), 135.7 (d, JCP = 39.9 Hz, arom.), 134.2 (s, arom.), 133.7
(s, arom.), 133.2 (s, arom.), 133.1 (s, arom.), 132.7 (s, arom.), 131.4
(s, arom.), 131.0 (s, arom.), 130.1 (s, arom.), 129.7 (s, arom.), 129.2
(s, arom.), 128.7 (s, arom.), 128.5 (d, JCP = 24.0 Hz, arom.), 128.3
(d, JCP = 18.0 Hz, arom.), 128.1 (s, arom.), 128.0 (s, arom.), 127.2
(s, arom.), 127.1 (s, arom.), 126.5 (s, arom.), 126.3 (s, arom.), 126.0
(s, arom.), 125.7 (d, JCP = 26.1 Hz, arom.), 124.9 (s, arom.), 123.9
(s, arom.), 122.9 (s, arom.), 122.7 (s, arom.), 122.0 (s, arom.), 121.3
2
2
176.8 (d, JPP = 72.8 Hz, phosphoramidite*), 61.9 (d, JPP
=
2
77.0 Hz, PPh3), 55.6 (d, JPP = 72.8 Hz, PPh3*) ppm. IR (neat so-
lid): ν = 3051 (w), 2964 (w), 1479 (m), 1235 (m), 1090 (m), 818
˜
(m) cm–1. HRMS: calcd. for C38H36ClNO2P235102Ru 737.0952;
found 737.0950. C38H36ClNO2P2Ru (737.17): calcd. C 61.91, H
4.92; found C 61.07, H 4.96.
[Ru(Ind)(PPh3)(5a)(diphenylallenylidene)]+[PF6]– (15a): In a typical
procedure, CH2Cl2 (3 mL) was added to a Schlenk flask containing
complex 12b (0.149 g, 0.145 mmol) and the orange solution was
cooled to 0 °C. (Et3O)PF6 (0.036 g, 0.147 mmol) was added as a
solution in CH2Cl2 (3 mL). The solution darkened slightly over 1 h
and then 1,1-diphenyl-2-propyn-1-ol (14a; 0.037 g, 0.177 mmol,
1.2 equiv.) was added. The solution quickly turned dark purple.
After 30 min, the cold bath was removed and the solution was
warmed to room temperature over 30 min. The solvent was re-
moved under oil-pump vacuum and the purple solid washed with
Et2O (4ϫ3 mL) and dried under vacuum to give 15a as a single
(s, arom.), 114.3 (d, JCP = 18.0 Hz, indenyl), 113.0 (d, JCP
=
2
24.0 Hz, indenyl), 90.4 (s, indenyl), 68.3 (d, JCP = 48.0 Hz, in-
denyl), 59.1 (s, indenyl), 54.9 (d, 2JCP = 68.1 Hz, NC), 49.0 (s, NCЈ),
3
21.7 (d, JCP = 21.9 Hz, CH3) ppm. 31P{1H} NMR (121 MHz,
2
CDCl3, 25 °C): δ = 172.0 (d, JPP = 58.6 Hz, phosphoramidite),
2
45.9 (d, JPP = 58.6 Hz, PPh ) ppm. IR (neat solid): ν = 3051 (w),
˜
3
2927 (w), 1584 (w), 1430 (m), 1221 (m), 949 (s) cm–1. HRMS: calcd.
for C62H50ClNO2P235102Ru 1039.2048; found 1039.2004.
C62H50ClNO2P2Ru (1039.54): calcd. C 71.63, H 4.85; found C
71.04, H 4.84.
diastereomer (0.163 g, 0.123 mmol, 85%); m.p. 173 °C (dec., capil-
3
lary). 1H NMR (300 MHz, CDCl3, 25 °C): δ = 8.25 (d, JHH
=
3
8.8 Hz, 1 H, arom.), 8.09 (d, JHH = 8.2 Hz, 1 H, arom.), 7.80 (d,
3
[RuCl(Ind)(PPh3){(R)-10}] (12d): Phosphoramidite (R)-10 (0.032 g,
0.14 mmol) was added as a solution in toluene (3 mL) to a Schlenk
flask containing [RuCl(Ind)(PPh3)2] (11; 0.109 g, 0.141 mmol). The
mixture was heated at 65 °C for 2 h in an oil bath after which the
solvent was removed under oil-pump vacuum. The resulting red
solid was purified by flash chromatography employing a 1ϫ11 cm
silica column. The remaining ligand and PPh3 were eluted with
CH2Cl2 and then the complex was eluted with CH2Cl2/tert-but-
ylmethyl ether (9:1, v/v), collecting the red band. The solvent was
removed under oil-pump vacuum to give complex 12d as an orange
solid in a 1:1 diastereomeric mixture (0.069 g, 0.094 mmol, 67%);
3JHH = 8.8 Hz, 1 H, arom.), 7.65 (d, JHH = 8.1 Hz, 1 H, arom.),
3
7.60–7.47 (m, 4 H, arom.), 7.34 (d, JHH = 8.5 Hz, 1 H, arom.),
3
7.28 (t, JHH = 7.0 Hz, 3 H, arom.), 7.22–6.70 (m, 37 H, arom.),
6.62 (d, 3JHH = 4.8 Hz, 2 H, arom.), 6.49 (br. s, 1 H, indenyl), 5.51
(br. s, 1 H, indenyl), 5.28 (br. s, 1 H, indenyl), 5.23 (s, CH2Cl2),
2
2
4.10 (d, JHH = 10.4 Hz, 1 H, NCHHЈ), 4.05 (d, JHH = 10.4 Hz,
2
1 H, NCHHЈ), 3.06 (d, JHH = 14.3 Hz, 1 H, NCHHЈ), 3.02 (d,
2JHH = 14.3 Hz, 1 H, NCHHЈ) ppm. 13C{1H} NMR (75 MHz,
2
CDCl3, 25 °C): δ = 293.8 (d, JCP = 21.9 Hz, Cα), 199.2 (s, Cβ),
160.3 (s, Cγ), 149.4 (d, JCP = 16.1 Hz, arom.), 147.9 (d, JCP
=
7.2 Hz, arom.), 143.0 (s, arom.), 136.6 (d, JCP = 2.6 Hz, arom.),
m.p. 99–100 °C (dec., capillary). 1H NMR (300 MHz, CDCl3, 135.0–133.0 (m, arom.), 132.6 (s, arom.), 132.5 (s, arom.), 131.8 (d,
25 °C):[36] δ = 7.74–7.57 (m, 2 H, arom.), 7.33–6.94 (m, 34 H,
JCP = 2.8 Hz, arom.), 131.5 (s, arom.), 131.4 (s, arom.), 130.9 (s,
arom.), 6.90–6.73 (m, 3 H, arom.), 6.73–6.57 (m, 3 H, arom.), 6.51– arom.), 130.1 (s, arom.), 129.4 (s, arom.), 129.3 (s, arom.), 129.2 (d,
6.37 (m, 2 H, arom.), 6.00–5.85 (m, 2 H, arom.), 5.09 (br. s, 1 H,
indenyl), 4.92 (br. s, 2 H, indenyl), 4.69 (br. s, 1 H, indenyl), 4.31
(br. s, 1 H, indenyl), 4.01 (br. s, 1 H, indenyl), 3.89–3.79 (m, 1 H,
JCP = 2.8 Hz, arom.), 128.9 (s, arom.), 128.8 (s, arom.), 128.7 (s,
arom.), 128.6 (s, arom.), 128.5–128.1 (m, arom.), 128.0 (s, arom.),
127.7 (s, arom.), 127.1 (s, arom.), 126.9 (s, arom.), 126.4 (s, arom.),
NCHCH3), 3.79–3.69 (m, 1 H, NCHCH3*), 3.45–3.32 (m, 1 H, 125.8 (s, arom.), 124.6 (s, arom.), 123.4 (s, arom.), 122.5 (d, JCP
NCHHЈ), 3.21–3.08 (m, 1 H, NCHHЈ*), 2.91–2.80 (m, 1 H, 2.2 Hz, arom.), 122.1 (d, JCP = 3.3 Hz, arom.), 121.6 (d, JCP
=
=
NCHHЈ), 2.78–2.65 (m, 1 H, NCHHЈ*), 1.89–1.57 (m, 5 H, 2 CH2, 2.7 Hz, arom.), 120.2 (s, arom.), 112.3 (d, JCP = 4.1 Hz, indenyl),
CHHЈ), 1.57–1.44 (m, 1 H, CHHЈ*), 1.37–1.23 (m, 2 H, 2 CHHЈ), 108.1 (s, indenyl), 94.1 (s, indenyl), 85.3 (s, indenyl), 84.2 (d, 2JCP
=
1278
www.eurjic.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 1269–1282

New Chiral-at-Metal Ruthenium Allenylidene Complexes
7.0 Hz, indenyl), 50.4 (s, CH2), 50.3 (s, CH2Ј) ppm. 31P{1H} NMR arom.), 120.7 (s, arom.), 116.2 (s, arom.), 112.2 (s, indenyl), 107.6
2
(121 MHz, CDCl3, 25 °C): δ = 169.5 (d, JPP = 34.0 Hz, phos-
(s, indenyl), 95.5 (s, indenyl), 82.7 (s, indenyl), 81.7 (s, indenyl),
2
1
phoramidite), 52.3 (d, JPP = 34.0 Hz, PPh3), –143.4 (septet, JPF
= 711 Hz, PF ) ppm. IR (neat solid): ν = 3056 (w), 2918 (w), 1935
50.4 (s, CH2), 50.3 (s, CH2), 28.2 (s, CH3) ppm. 31P{1H} NMR
2
(121 MHz, CDCl3, 25 °C): δ = 174.3 (d, JPP = 38.2 Hz, phos-
˜
6
(s, =C=C=C), 1586 (w), 1223 (m), 1058 (s), 1028 (s) cm–1. HRMS: phoramidite), 55.9 (d, JPP = 38.2 Hz, PPh3), –143.4 (septet, JPF
2
1
calcd. for C76H58NO2P2102Ru 1180.2985; found 1180.2981.
C76H58F6NO2P3Ru·(CH2Cl2)0.5 (1367.73): calcd. C 67.18, H 4.35;
found C 67.02, H 4.55.
= 711 Hz, PF ) ppm. IR (neat solid): ν = 3267 (m, H O), 3051 (w),
˜
6 2
2923 (w), 1949 (s, =C=C=C), 1546 (w), 1430 (m), 1221 (m), 940
(s) cm–1. HRMS: calcd. for C69H54NO3P2102Ru 1108.2622; found
1108.2654. C69H54F6NO3P3Ru·H2O (1271.17): calcd. C 65.20, H
4.44; found C 64.93, H 4.30.
[Ru(Ind)(PPh3)(5b)(methylphenylallenylidene)]+[PF6]– (15b): Yield
0.082 g (0.064 mmol, 66%) from 12b (0.100 g, 0.0977 mmol) and
1
14b (0.017 g, 0.116 mmol); m.p. 173 °C (dec., capillary). H NMR
[Ru(Ind)(PPh3){(R)-binol-N,N-dibenzylphosphoramidite}{bis(4-fluo-
rophenyl)allenylidene}]+[PF6]– (15d): Yield 0.135 g (0.0992 mmol,
76%) from 12b (0.102 g, 0.0995 mmol) and 3,3-bis(4-fluorophenyl)-
2-propyn-1-ol (14d, 0.029 g, 0.119 mmol); m.p. 196–198 °C (dec.,
(300 MHz, CDCl3, 25 °C): δ = 8.30 (d, 3JHH = 8.7 Hz, 1 H, arom.),
3
3
8.16 (d, JHH = 8.1 Hz, 1 H, arom.), 7.87 (d, JHH = 8.4 Hz, 1 H,
arom.), 7.79 (t, JHH = 7.8 Hz, 2 H, arom.), 7.72–7.54 (m, 5 H,
arom.), 7.48 (d, JHH = 8.4 Hz, 1 H, arom.), 7.40–6.80 (m, 35 H,
3
3
1
3
capillary). H NMR (300 MHz, CDCl3, 25 °C): δ = 8.25 (d, JHH
3
arom.), 6.56 (br. s, 1 H, indenyl), 5.38 (br. s, 2 H, indenyl), 4.01 (d,
= 8.8 Hz, 1 H, arom.), 8.10 (d, JHH = 8.1 Hz, 1 H, arom.), 7.81
2JHH = 10.8 Hz, 1 H, CHHЈ), 3.96 (d, 2JHH = 10.8 Hz, 1 H, CHHЈ),
(d, 3JHH = 9.0 Hz, 1 H, arom.), 7.66 (d, 3JHH = 8.0 Hz, 1 H, arom.),
3
2
3
3.42 (q, JHH = 7.2 Hz, 1 H, CH2, Et2O), 3.15 (d, JHH = 13.8 Hz, 7.55–7.50 (m, 2 H, arom.), 7.37 (d, JHH = 8.4 Hz, 1 H, arom.),
2
3
1 H, CHHЈ), 3.10 (d, JHH = 13.8 Hz, 1 H, CHHЈ), 1.64 (s, 3 H,
7.26 (t, JHH = 7.6 Hz, 3 H, arom.), 7.19–7.02 (m, 16 H, arom.),
CH3), 1.13 (d, JHH = 6.9 Hz, 1.5 H, CH3, Et2O) ppm. 13C{1H} 7.00–6.96 (m, 6 H, arom.), 6.95–6.90 (m, 5 H, arom.), 6.86–6.82
3
NMR (75 MHz, CDCl3, 25 °C): δ = 297.5 (dd, JCP = 23.5, 2JCP
=
(m, 11 H, arom.), 6.66 (d, JHH = 8.9 Hz, 1 H, arom.), 6.56 (br. s,
2
3
3
20.7 Hz, Cα), 195.5 (d, JCP = 13.8 Hz, Cβ), 162.8 (s, Cγ), 149.7 (s, 1 H, indenyl), 5.53 (br. s, 1 H, indenyl), 5.22 (br. s, 1 H, indenyl),
2
2
arom.), 149.5 (s, arom.), 147.9 (d, JCP = 27.6 Hz, arom.), 141.6 (s,
arom.), 136.7 (d, JCP = 10.8 Hz, arom.), 134.0 (s, arom.), 133.5–
4.07 (d, JHH = 10.5 Hz, 1 H, CHHЈ), 4.02 (d, JHH = 10.5 Hz, 1
2
2
H, CHHЈ), 3.04 (d, JHH = 14.2 Hz, 1 H, CHHЈ), 2.99 (d, JHH
=
133.3 (m, arom.), 132.7 (s, arom.), 131.9 (s, arom.), 131.6 (s, arom.), 14.2 Hz, 1 H, CHHЈ) ppm. 13C{1H} NMR (75 MHz, CDCl3,
131.4 (s, arom.), 131.1 (s, arom.), 130.6 (s, arom.), 129.6–127.8 (m, 25 °C): δ = 291.9–291.3 (m, Cα), 198.5 (s, Cβ), 166.9 (s, Cγ), 163.5
arom.), 127.6 (d, JCP = 24.6 Hz, arom.), 127.1 (s, arom.), 126.8 (s,
(s, arom.), 155.5 (s, arom.), 149.3 (d, JCF = 61.5 Hz, arom.), 147.8
arom.), 126.4 (s, arom.), 125.9 (s, arom.), 124.6 (s, arom.), 123.7 (s, (d, JCP = 28.8 Hz, arom.), 139.2 (s, arom.), 136.6 (s, arom.), 133.7
arom.), 122.4 (s, arom.), 121.9–121.7 (m, arom.), 120.3 (s, arom.), (s, arom.), 133.6 (s, arom.), 133.2 (s, arom.), 132.4 (s, arom.), 131.7
2
112.4 (s, indenyl), 108.2 (d, JCP = 16.2 Hz, indenyl), 95.1 (s, in-
(s, arom.), 131.3 (s, arom.), 130.8 (br. s, arom.), 130.0 (s, arom.),
129.2 (s, arom.), 128.8 (s, arom.), 128.6 (s, arom.), 128.5 (s, arom.),
128.3 (br. s, arom.), 128.0 (s, arom.), 127.6 (s, arom.), 127.1 (d, JCP
2
denyl), 83.7 (d, JCP = 30.3 Hz, indenyl), 82.7 (s, indenyl), 65.9 (s,
CH2, Et2O), 50.3 (s, CH2), 50.2 (s, CH2), 30.3 (s, CH3), 15.4 (s,
CH3, Et2O) ppm. 31P{1H} NMR (121 MHz, CDCl3, 25 °C): δ = = 18.3 Hz, arom.), 126.9 (s, arom.), 126.4 (s, arom.), 125.9 (s,
2
2
171.4 (d, JPP = 37.6 Hz, phosphoramidite), 53.4 (d, JCP
37.6 Hz, PPh3), –143.4 (septet, JPF = 711 Hz, PF6) ppm. IR (neat arom.), 121.6 (s, arom.), 120.0 (s, arom.), 116.4 (s, arom.), 116.1 (s,
=
arom.), 124.8 (s, arom.), 123.5 (s, arom.), 122.4 (s, arom.), 122.0 (s,
1
solid): ν = 3052 (w), 1942 (s, =C=C=C), 1585 (w), 1224 (m), 1066
arom.), 112.4 (s, arom.), 107.6 (s, indenyl), 94.3 (s, indenyl), 85.7
(s, indenyl), 83.9 (d, 2JCP = 28.8 Hz, indenyl), 66.0 (s, indenyl), 50.3
(s, NCH2), 50.1 (s, NCH2) ppm. 31P{1H} NMR (121 MHz, CDCl3,
˜
(w), 828 (s) cm–1. HRMS: calcd. for C71H56NO2P2102Ru 1118.2828;
found 1118.2827. C71H52F6NO2P3Ru·(Et2O)0.25 (1277.69): calcd. C
67.47, H 4.60; found C 67.28, H 4.48.
2
25 °C): δ = 169.8 (d, JPP = 35.2 Hz, phosphoramidite), 52.8 (d,
1
2JPP = 35.2 Hz, PPh3), –143.5 (septet, JPF = 711 Hz, PF6) ppm.
[Ru(Ind)(PPh3)(5b){(2-furyl)methylallenylidene}]+[PF6]– (15c): Yield
0.116 g (0.0913 mmol, 94%) from 12b (0.100 g, 0.0976 mmol) and
2-(2-furyl)-3-butyn-2-ol (14c; 0.014 g, 0.017 mmol); m.p. 188–
IR (neat solid): ν = 3053 (w), 1938 (s, =C=C=C), 1592 (m), 1502
˜
(w), 1226 (m), 952 (m), 831 (s) cm–1. HRMS: calcd. for
C76H56NO2P2F2102Ru 1216.2797; found 1216.2761. C76H56F8NO2-
P3Ru (1361.24): calcd. C 67.06, H 4.15; found C 66.60, H 3.97.
1
190 °C (dec., capillary). H NMR (300 MHz, CD2Cl2, 25 °C): δ =
3
3
8.23 (d, JHH = 8.8 Hz, 1 H, arom.), 8.10 (d, JHH = 8.4 Hz, 1 H,
3
arom.), 7.89 (s, 1 H, arom.), 7.78 (d, JHH = 8.8 Hz, 1 H, arom.),
[Ru(Ind)(PPh3)(5b){methyl(4-methoxyphenyl)allenylidene}]+[PF6]–
7.72–7.67 (m, 2 H, arom.), 7.57–7.51 (m, 1 H, arom.), 7.37 (d, 3JHH (15e): Yield 0.083 g (0.064 mmol, 66%) from 12b (0.100 g,
= 8.3 Hz, 1 H, arom.), 7.27–7.23 (m, 8 H, arom.), 7.17–7.12 (m, 6 0.0979 mmol) and 2-(4-methoxylphenyl)-3-butyn-2-ol (14e; 0.021 g,
H, arom.), 7.11–7.00 (m, 8 H, arom.), 7.00–6.85 (m, 13 H, arom.),
0.119 mmol); m.p. 150–152 °C (dec., capillary). 1H NMR
6.61–6.59 (m, 1 H, arom.), 6.37 (br. s, indenyl), 5.20 (br. s, indenyl), (300 MHz, CDCl3, 25 °C): δ = 8.21 (d, 3JHH = 8.8 Hz, 1 H, arom.),
5.11 (br. s, indenyl), 3.90 (d, 2JHH = 11.0 Hz, 1 H, CHHЈ), 3.84 (d,
8.07 (d, JHH = 8.1 Hz, 1 H, arom.), 7.79 (d, JHH = 8.8 Hz, 1 H,
3
3
2JHH = 11.0 Hz, 1 H, CHHЈ), 3.01 (d, 2JHH = 13.4 Hz, 1 H, CHHЈ),
arom.), 7.71–7.65 (m, 2 H, arom.), 7.53–7.49 (m, 3 H, arom.), 7.39
2
3
2.95 (d, JHH = 13.4 Hz, 1 H, CHHЈ), 1.50 (s, H2O), 1.46 (s, 3 H, (d, JHH = 8.51 Hz, 1 H, arom.), 7.30–7.19 (m, 3 H, arom.), 7.18–
CH3) ppm. 13C{1H} NMR (75 MHz, CD2Cl2, 25 °C): δ = 282.7–
7.10 (m, 10 H, arom.), 7.08–6.80 (m, 19 H, arom.), 6.76–6.60 (m,
4 H, arom.), 6.31 (br. s, 1 H, indenyl), 5.22 (br. s, 2 H, indenyl),
281.6 (m, Cα), 185.2 (s, Cβ), 160.9 (s, Cγ), 151.5 (s, arom.), 150.0
(d, JCP = 16.1 Hz, arom.), 148.4 (d, JCP = 7.3 Hz, arom.), 145.3 (s, 3.97 (d, JHH = 10.6 Hz, 1 H, CHHЈ), 3.92 (d, JHH = 10.6 Hz, 1
arom.), 142.4 (s, arom.), 139.7 (s, arom.), 137.4 (br. s, arom.), 136.7 H, CHHЈ), 3.87 (s, 3 H, OCH3), 3.02 (d, JHH = 13.0 Hz, 1 H,
(d, JCP = 10.4 Hz, arom.), 133.8 (br. s, arom.), 133.0 (s, arom.),
132.3 (s, arom.), 131.8 (s, arom.), 131.4 (d, JCP = 8.4 Hz, arom.),
130.7 (br. s, arom.), 129.8 (s, arom.), 129.2 (d, JCP = 4.4 Hz, arom.),
2
2
2
2
CHHЈ), 2.97 (d, JHH = 13.0 Hz, 1 H, CHHЈ), 1.59 (s, 3 H,
CH3) ppm. 13C{1H} NMR (75 MHz, CDCl3, 25 °C): δ = 282.0 (dd,
2
2JCP = 23.5, JCP = 21.3 Hz, Cα), 181.9 (s, Cβ), 166.0 (s, Cγ), 163.6
128.9 (s, arom.), 128.7 (s, arom.), 128.4 (s, arom.), 128.2 (s, arom.), (s, arom.), 149.8 (d, JCP = 15.5 Hz, arom.), 148.0 (d, JCP = 7.5 Hz,
128.0 (s, arom.), 127.7 (d, JCP = 4.4 Hz, arom.), 127.3 (d, JCP
=
arom.), 136.9 (d, JCP = 2.3 Hz, arom.), 135.8 (s, arom.), 133.3 (br.
6.2 Hz, arom.), 127.1 (s, arom.), 126.6 (s, arom.), 126.0 (s, arom.),
s, arom.), 132.6 (s, arom.), 131.8 (s, arom.), 131.3 (s, arom.), 131.1
124.9 (s, arom.), 124.0 (s, arom.), 122.9 (s, arom.), 122.3–121.9 (m, (s, arom.), 130.4 (br. s, arom.), 128.9 (d, JCP = 2.3 Hz, arom.), 128.7
1279
Eur. J. Inorg. Chem. 2011, 1269–1282
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org

S. Costin, A. K. Widaman, N. P. Rath, E. B. Bauer
FULL PAPER
(s, arom.), 128.6 (s, arom.), 128.5 (s, arom.), 128.2 (s, arom.), 128.0 Oxford Cryostream LT device. Intensity data were collected by a
(s, arom.), 127.9 (s, arom.), 127.8 (s, arom.), 127.2 (s, arom.), 126.9 combination of ω and φ scans. Apex II, SAINT, and SADABS[41]
(s, arom.), 126.2 (s, arom.), 125.8 (s, arom.), 124.6 (s, arom.), 123.9 software packages were used for data collection, integration, and
(s, arom.), 122.4 (d, JCP = 2.3 Hz, arom.), 122.0 (d, JCP = 3.5 Hz, correction of systematic errors, respectively.
arom.), 121.8 (d, JCP = 2.9 Hz, arom.), 120.4 (s, arom.), 115.2 (s,
Crystal data and intensity data collection parameters are listed in
Table 2. Structure solution and refinement were carried out by
2
arom.), 111.7 (s, arom.), 107.9 (d, JCP = 4.6 Hz, indenyl), 95.4 (s,
2
indenyl), 81.8 (d, JCP = 7.7 Hz, indenyl), 80.2 (s, indenyl), 66.1 (s,
using the SHELXTL-PLUS software package.[39] The structures
indenyl), 56.5 (s, OCH3), 50.1 (s, NCH2), 50.0 (s, NCH2Ј), 29.3 (s,
were solved by direct methods and refined successfully in the space
CH3) ppm. 31P{1H} NMR (121 MHz, CDCl3, 25 °C): δ = 173.1 (d,
groups P65 (5b), P21 (12b), and P1 ([15a]+[PF6]–, [15b]+[PF6]–, and
2
2JPP = 38.8 Hz, phosphoramidite), 54.6 (d, JPP = 38.8 Hz, PPh3),
[15d]+[PF6]–). The non-hydrogen atoms were refined anisotropically
to convergence. All hydrogen atoms were treated by using the ap-
propriate riding model (AFIX m3). The structure of 12b shows
–143.5 (septet, 1JPF = 711 Hz, PF ) ppm. IR (neat solid): ν = 3053
˜
6
(w), 1941 (s, =C=C=C), 1587 (s), 1225 (w), 1172 (m), 832 (m) cm–1.
HRMS: calcd. for C72H58NO3P2102Ru 1148.2935; found 1148.2966.
disorder in the ligand as well as in the solvent. The structure of
C72H58F6NO3P3Ru (1293.22): calcd. C 66.87, H 4.52; found C
66.58, H 4.58.
[15a]+[PF6]– shows disorder in the solvent. The disorders have been
modeled with partial occupancy atoms. Two phenyl rings and the
six-membered ring fused to the Cp ring of [15d]+[PF6]– were disor-
X-ray Structure Determination for 5b, 12b, [15a]+[PF6]–,
[15b]+[PF6]–, and [15d]+[PF6]–: X-ray quality crystals of 5b were ob-
tained by addition of hexanes to a solution of 5b in CH2Cl2 at
–10 °C. X-ray quality crystals of 12b were obtained by addition of
Et2O to a solution of 12b in CH2Cl2, which was stored at –10 °C
for several days. X-ray quality crystals of [15a]+[PF6]–, [15b]+-
[PF6]–, and [15d]+[PF6]– were obtained by slow diffusion of Et2O
into a solution of [15a]+[PF6]–, [15b]+[PF6]–, and [15d]+[PF6]– in
CH2Cl2 at –10 °C.
–
dered. The PF6 anion was also disordered. The disorders were
resolved with partial occupancy atoms and were refined with geo-
metrical restraints and thermal parameter restraints.
CCDC-798362 (for 5a), -726745 (for 12b), -726746 (for
[15a][PF6]), -730038 (for [15b][PF6]), and -797367 (for [15d][PF6])
contain 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.
Preliminary examination and X-ray data collection were performed
using a Bruker Kappa Apex II Charge-Coupled Device (CCD) De-
tector system single-crystal X-ray diffractometer equipped with an
Supporting Information (see footnote on the first page of this arti-
cle): Experimental data for compounds 16, dynamic NMR spectra
Table 2. Crystallographic parameters.
5b
12b·(CH2Cl2)
[15a][PF6]·(CH2Cl2)
[15b][PF6]·(CH2Cl2)2
[15d][PF6]
Empirical formula
Mr
C
511.53
293(2)/0.71073
hexagonal
P6(5)
34H26NO2P
C62H50Cl3NO2P2Ru C77H60Cl2F6NO2P3Ru
C73H60Cl4F6NO2P3Ru
1433.00
100(2)/0.71073
triclinic
C76H56F8NO2P3Ru
1361.20
100(2)/0.71073
triclinic
1110.39
1410.14
100(2)/0.71073
triclinic
P1
T [K]/λ [Å]
Crystal system
Space group
Unit cell dimensions
a [Å]
b [Å]
c [Å]
α [°]
β [°]
100(2)/0.71073
monoclinic
P21
P1
P1
23.743(6)
23.743(6)
9.373(3)
90
90
120
4576(2)/6
1.114
0.118
10.6869(6)
14.1253(8)
17.5760(11)
90
98.355(3)
90
11.2299(5)
11.6496(5)
14.4331(9)
107.864(3)
99.934(2)
107.804(2)
1635.53(14)/1
1.432
11.0664(8)
12.0459(10)
13.5914(12)
107.535(4)
96.060(4)
109.111(3)
1589.9(2)/1
1.497
10.7555(5)
11.9134(5)
14.1022(10)
108.600(4)
98.130(4)
107.670(3)
1573.99(15)/1
1.436
γ [°]
V [Å3]/Z
2625.0(3)/2
1.405
ρcalcd. [Mgm–3
]
Abs. coeff. [mm–1
]
0.558
0.461
0.557
0.399
F(000)
1608
1140
722
732
696
Crystal size [mm]
θ range [°]
Index ranges
0.51ϫ0.13ϫ0.10 0.34ϫ0.30ϫ0.28
0.37ϫ0.27ϫ0.21
2.14–35.14
–18ՅhՅ7,
–18ՅkՅ18,
–23ՅlՅ23
30278
0.40ϫ0.29ϫ0.28
1.61–33.05
–16ՅhՅ16,
–18ՅkՅ17,
–19ՅlՅ20
78842
0.23ϫ0.18 ϫ0.14
1.94–27.33
–13ՅhՅ13,
–15ՅkՅ15,
–18ՅlՅ17
57561
2.39–25.44
–28ՅhՅ28,
–28ՅkՅ28,
–11ՅlՅ10
95194
1.86–4.02
–16ՅhՅ15,
–15ՅkՅ22,
–27ՅlՅ27
59037
Reflections collected
Independent refl.
5596
18483
19876
20252
13669
[R(int) = 0.0615]
[R(int) = 0.0316]
[R(int) = 0.026]
[R(int) = 0.029]
[R(int) = 0.055]
Abs. correction
Max./min. transmission
Data/restraints/param.
Goodness-of-fit on F2
Final R indices
[IϾ2σ(I)]
semi-empirical from equivalents
0.9880/0.9420
5596/1/343
1.090
R1 = 0.0479
wR2 = 0.1130
R1 = 0.0873
wR2 = 0.1347
0.298/–0.233
–0.02(12)
0.8594/0.8312
18483/97/715
1.020
R1 = 0.0485
wR2 = 0.1174
R1 = 0.0622
wR2 = 0.1271
1.984/–0.664
–0.01(2)
0.9102/0.8464
19876/89/901
1.018
0.8588/0.8076
20252/23/821
1.046
0.9478/0.9132
13669/123/1025
1.070
R1 = 0.0447
wR2 = 0.1166
R1 = 0.0494
wR2 = 0.1210
1.470/–0.859
–0.031(18)
R1 = 0.0416
wR2 = 0.1017
R1 = 0.0482
wR2 = 0.1063
0.999/–0.852
–0.014(14)
R1 = 0.0323
wR2 = 0.0862
R1 = 0.0336
wR2 = 0.0871
1.032/–1.144
–0.009(10)
R indices
(all data)
Largest diff. peak/hole [eÅ–3
Absolute structure parameter
]
1280
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© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 1269–1282

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Acknowledgments
We thank the University of Missouri – St. Louis for support. Fund-
ing from the National Science Foundation (NSF) for the purchase
of the ApexII diffractometer (MRI, CHE-0420497), the NMR
spectrometer (CHE-9974801), and the mass spectrometer (CHE-
9708640) is acknowledged.
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