Some binding modes of 2-aminopyridine to ruthenium(II) fragments

Article abstract of DOI:10.1039/b302416d

The bonding modes of 2-aminopyridine (apy) (1 equiv.) with some ruthenium(II) fragments were studied. In the reaction of [RuCp(CH3CN)3]⁺ (1) one acetonitrile ligand is replaced with apy being κ¹(N-pyridine) bonded. This complex is very air-sensitive trasnforming into dinuclear [RuCp(μ³-dapy)]2²⁺ where dapy is deprotonated apy. On the other hand, [RuCl2(PPh3)3] exchanges one phosphine ligand for apy which is coordinated in the κ²N,N' mode. Similar to 1, the complexes [RuCp(CH3CN)2L]⁺ (L = PMe3, PPh3 or CO), also react with apy to give [RuCp(CH3CN)(L)(κ¹N-apy)]⁺. These compounds were reacted with HCCPh with appreciable differences depending on L. While with L = CH3CN no clean reacion took place, with L = PMe3 an η³-allyl carbene is formed with release of apy. With L = PPh3 or CO, dapy stabilized a Fisher carbene through chelation. Finally, if 1 is reacted with 2-N,N-dimethylaminopyridine (dmapy), all acetonitriles are displaced in favor of η⁶-coordinated dmapy.

Full text of DOI:10.1039/b302416d

View Article Online / Journal Homepage / Table of Contents for this issue
Some binding modes of 2-aminopyridine to ruthenium(II)
fragments
Christina M. Standfest-Hauser,a Kurt Mereiter,b Roland Schmida and Karl Kirchner*a
a Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9,
A-1060 Vienna, Austria. E-mail: kkirch@mail.zserv.tuwien.ac.at
b Institute of Chemical Technologies and Analytics, Vienna University of Technology,
Getreidemarkt 9, A-1060 Vienna, Austria
Received 3rd March 2003, Accepted 15th April 2003
First published as an Advance Article on the web 30th April 2003
The bonding modes of 2-aminopyridine (apy) (1 equiv.) with some ruthenium() fragments were studied. In the
reaction with [RuCp(CH3CN)3]ϩ (1) one acetonitrile ligand is replaced with apy being κ1(N-pyridine) bonded. This
complex is very air-sensitive transforming into dinuclear [RuCp(µ3-dapy)]22ϩ where dapy is deprotonated apy. On the
other hand, [RuCl2(PPh3)3] exchanges one phosphine ligand for apy which is coordinated in the κ2N,NЈ mode. Similar
to 1, the complexes [RuCp(CH3CN)2L]ϩ(L = PMe3, PPh3 or CO), also react with apy to give [RuCp(CH3CN)(L)-
1
ϩ
᎐
(κ N-apy)] . These compounds were reacted with HC᎐CPh with appreciable differences depending on L. While
᎐
with L = CH3CN no clean reaction took place, with L = PMe3 an η3-allyl carbene is formed with release of apy.
With L = PPh3 or CO, dapy stabilizes a Fischer carbene through chelation. Finally, if 1 is reacted with 2-N,N-
dimethylaminopyridine (dmapy), all acetonitriles are displaced in favor of η6-coordinated dmapy.
for parent pyridine and some of its derivatives,8,9 those of apy
(E) to our knowledge remain still unknown.
Introduction
The use of chelating ligands which form four-membered and
thus strained ring systems is a promising route for creating
vacant coordination sites in transition metal complexes where
substrates can be attached for further conversions. One such an
example is 2-aminopyridine (apy) (Chart 1, A) which is able to
undergo facile opening of the strained M–N–C–N ring at the
M–NH2 bond allowing, for instance, coordination of alkynes to
yield vinylidene and cyclic aminocarbenes.1,2 Because of lesser
strain five-membered rings are typically more favored.3 This is
also effected by bridging two metal centers, with or without an
additional metal–metal bond (B, BЈ).1,4 Interestingly, complexes
with κ2N,NЈ four-membered ring systems with apy have so far
been hypothesized only as putative intermediates, while com-
plexes containing a deprotonated apy are very common.5,6
Chelate formation, however, is not the only way conceivable for
binding apy to a metal fragment. Some possible structural types
of the coordination modes of apy are summarized in Chart 1.
In the context of these varied bonding properties of apy, we
investigate in the present work the ways in which apy interacts
with [RuCp(CH3CN)3]PF6 (1) as the starting material and
derivatives thereof in which one acetonitrile ligand is replaced
with PMe3 (2a), PPh3 (2b) or CO (3). In addition, [RuCl2-
(PPh3)3] is investigated. This topic, while interesting by itself,
may aid in better understanding the behavior of apy com-
plexes in catalytic conversions. It may be worthwhile to
emphasize the distinct chemical nature of the three nitrogen
atoms involved, viz. the sp-N of CH3CN, the sp2-N of pyridine
and the sp3/sp2-N of the amine group.
Results and discussion
Treatment of 1 with apy (1 equiv.) results in the formation of
[RuCp(κ1N-apy)(CH3CN)2]PF6 (5a) in 76% isolated yield,
which from 1H and 13C{1H} NMR and elemental data is clearly
κ1N(py) bound rather than κ2N,NЈ (Scheme 1). This complex is
very air-sensitive both in solution and in the solid state (see
below). The finding that only one apy ligand is attached is
noteworthy since in using parent pyridine under otherwise the
ϩ
]
same conditions, mixtures of [RuCp(py)n(CH3CN)3Ϫn
(n =
1–3) are obtained. On the other hand, the mono-pyridine com-
plex could be isolated using 2-methylpyridine (and others).10 As
claimed by Fish et al., this indicates that steric crowding around
nitrogen impedes N-bonding. In fact, with 2,4,6-trimethyl-
pyridine only the π-bonded complex is provided. Similarly,
[RuCp(2-Mepy)(CH3CN)2]ϩ is prone to release the acetonitriles
to give, in an N to π rearrangement, [RuCp(η6-2-Mepy)]ϩ.
This feature is also observed in the present work. Thus, if
1 is reacted with the bulkier 2-N,N-dimethylaminopyridine
(dmapy), [RuCp(η6-dmapy)]PF6 (9) is obtained (Scheme 2). The
formulation was verified by a combination of elemental analy-
sis, 1H and 13C{1H} NMR spectroscopy. Furthermore, a single-
crystal X-ray analysis revealed the structure which is illustrated
in Fig. 1 with selected bond distances reported in the figure
legend. To the best of our knowledge, this appears to be the first
structurally characterized example of a ruthenium complex
featuring an η6-coordinated pyridine (and apy) ligand. In
view of the literature11,12 it did not come as a surprise that
the η6-coordinated dmapy ligand is not planar but displays a
Chart 1
N(κ1)-bonding (C) occurs typically via the pyridine nitrogen
and happens particularly if the metal fragment is reluctant to
accept six electrons resulting from π coordination. A typical
example is provided by some planar platinum() complexes.7
On the other hand, N(κ1)-bonding via the weaker amine
nitrogen (D) is rather exceptional and may occur only if
coordination at the pyridine N-donor site is not feasible for
steric reasons. Finally, while π-pyridine complexes are known
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
D a l t o n T r a n s . , 2 0 0 3 , 2 3 2 9 – 2 3 3 4
2329

View Article Online
Scheme 1
Fig. 1 (Left) Structural view of [RuCp(η6-dmapy)]PF6 (9) showing 50% thermal ellipsoids (PF6 omitted for clarity). Selected bond lengths (Å):
Ru–C(1–5)av 2.179(2), Ru–C(6) 2.350(2), Ru–C(7) 2.202(2), Ru–C(8) 2.195(2), Ru–C(9) 2.214(2), Ru–C(10) 2.179(2), Ru–N(1) 2.228(2), C(6)–C(7)
1.430(3), C(6)–N(1) 1.382(2), C(6)–N(2) 1.335(2), C(10)–N(1) 1.377(3), C(11)–N(2) 1.454(3), C(12)–N(2) 1.460(3). (Right) Optimized DFT/B3LYP
geometry of [RuCp(η6-NC5H4NH2)]ϩ.
Ϫ
the bending in this case is purely electronic in nature and not a
packing effect stems from DFT/B3LYP calculations on the
model complexes [RuCp(η6-NC5H4NH2)]ϩ and [RuCp(η6-C6-
H5NH2)]ϩ. The optimized structures of these complexes are
shown in Figs. 1 and 2. In agreement with the X-ray structural
data, both the η6-NC5H4NH2 and η6-C6H5NH2 rings were cal-
culated to be bent, by about 10 and 8Њ, respectively, in excellent
agreement with experimental data.
To study the effect of co-ligands we also reacted apy with
[RuCp(CH3CN)2L]PF6, where L = PMe3 (2a), PPh3, (2b) or CO
(3). In all these cases we obtained the complexes [RuCp(CH3-
CN)(L)(κ1N-apy)]ϩ (5b–d) in high yields, in full conformity
with 1 (Scheme 1). Dramatic differences, however, are observed
᎐
upon the onward reaction with the alkyne HC᎐CPh. While with
᎐
5a no clean reaction took place with a complex mixture of
organic products found, with 5b the known η3-allyl carbene
complex [RuCp(᎐C(Ph)(η3-CHC(Ph)CHPMe )]PF (6) was
᎐
3
6
obtained following release of apy (Scheme 1). Mechanistic
aspects of this conversion have been discussed previously.13
With 5c and 5d, on the other hand, the cyclic amino carbenes
[RuCp(PPh )(᎐C(CH )PhNH-py)]PF (7) and [RuCp(CO)-
᎐
3
2
6
(᎐C(CH )PhNHpy)]PF (8) were afforded in 78 and 84% iso-
᎐
2
6
Scheme 2
lated yields, respectively. Thus, apy remains in the complex and
upon deprotonation stabilizes a Fischer carbene through chel-
ation. Despite the fact that no vinylidene intermediates could be
observed, such species are most likely key intermediates on the
way to aminocarbene complexes as outlined already recently.1,14
The carbene complexes are air-stable both in solution and in
significant shift of the ipso-carbon bearing the NMe2 substi-
tuent out of the mean aromatic plane away from the CpRu
fragment by 0.181(3) Å equivalent to 15Њ folding of the ring
(angle between the planar part of the pyridine ligand and the
N(1)–C(7)–C(6)–N(2) plane is 11.5(2)Њ, see Fig. 1). A reason-
able explanation is that the surplus of π electron density arising
from the π-donor substituent NR2 becomes less intense by this
kind of distortion. For comparison purposes, we also prepared
the analogous ruthenium N,N-dimethylaniline complex
[RuCp(η6-C6H5NMe2)]PF6 (10) according to Scheme 2. The
structure as determined by X-ray crystallography, is shown in
Fig. 2. It also reveals a pronounced folding of the arene ring
with C6 bent away from the RuCp unit by 0.125(3)Њ equivalent
to a 10Њ folding of the ring (angle between the planar part of the
phenyl ligand and C(7)–C(11)–C(6)–N(1) plane measures
6.4(2)Њ, see Fig. 2). Additional support for the supposition that
1
the solid state and were characterized by H, 13C{1H} and
31P{1H} NMR spectroscopy and elemental analysis. In the
13C{1H} NMR spectra of 7 and 8 the carbene moiety is identi-
fied by downfield signals at 275.7 and 275.9 ppm.14 Other
spectral changes accompanying the transformation to amino
carbene complexes include, for 7, a characteristic broad reson-
ance at 12.09 ppm assignable to the NH proton. For 8, we were
unable to locate the NH proton.
As mentioned above, 5a is not air-stable. Upon exposure to
air, the yellow solution of 5a in acetone rapidly turned dark
green. NMR monitoring revealed the formation of a dia-
magnetic species which after work-up was isolated in 84% yield
D a l t o n T r a n s . , 2 0 0 3 , 2 3 2 9 – 2 3 3 4
2330

View Article Online
Fig. 2 (Left) Structural view of [RuCp(η6-C6H5NMe2)]PF6 (10) showing 50% thermal ellipsoids (only the first of the two crystallographically
independent complexes is displayed; PF6Ϫ omitted for clarity). Selected bond lengths (Å): Ru–C(1–5)av 2.167(7), Ru–C(6) 2.344(4), Ru–C(7) 2.215(5),
Ru–C(8) 2.194(6), Ru–C(9) 2.221(5), Ru–C(10) 2.212(6), Ru–C(11) 2.223(5), C(6)–N(1) 1.368(6), C(12)–N(1) 1.460(7), C(13)–N(1) 1.446(7),
C(6)–C(7) 1.414(8), C(6)–C(11) 1.444(7), C(7)–C(8) 1.402(8), C(8)–C(9) 1.389(9), C(9)–C(10) 1.417(10), C(10)–C(11) 1.425(8). (Right) Optimized
DFT/B3LYP geometry of [RuCp(η6-C6H5NH2)]ϩ.
as the dinuclear complex [RuCp(µ3-dapy)]2(PF6)2 (11) as shown
in Scheme 3 (dapy = deprotonated apy). Support for this form-
ligand has been deprotonated and acts both as a κ2N,NЈ chelat-
ing and a µ3-bridging ligand. The core of the dinuclear complex
consists of a four-membered Ru–N–Ru–N ring. The N(2)–
Ru(1)–N(4) and N(2)–Ru(2)–N(4) angles are 93.4(1) and
93.2(1)Њ, respectively. The Ru(1)–Ru(2) distance of 2.652(1) Å
clearly indicates the presence of a metal–metal single bond.15
The two dapy ligands form a four-membered ring system with
N(1)–Ru(1)–N(2) and N(3)–Ru(2)–N(4) angles of 63.9(1)Њ.
The two bridging NH groups of the complex form straight
N–H ؒ ؒ ؒ F hydrogen bonds to one F atom of the two crystallo-
1
ulation comes from elemental analysis as well as from H and
1
13C{1H} NMR spectroscopy. In the H NMR spectrum the
hydrogen atoms of the Cp ring were downfield shifted to 6.01
ppm indicative of an oxidation state higher than ϩ. The NH
proton gives rise to a characteristic low-field shifted signal at
11.75 ppm. Similarly, in the 13C{1H} NMR spectrum the ring
carbon atoms of the Cp ligand were found to be downfield
shifted appearing as a singlet at 91.0 ppm. Based on these find-
ings and the diamagnetic nature of 11, the Ru() metal center
was apparently oxidized to Ru() forming a binuclear species
with a metal–metal bond. The single-crystal X-ray crystallo-
graphic analysis of 11 depicted in Fig. 3 confirms the dimeric
nature of this compound.
Ϫ
graphically independent PF6 octahedra (N ؒ ؒ ؒ F = 2.941(2)
and 3.052(2) Å).
Finally, we have reacted apy (1 equiv.) with [RuCl2(PPh3)3]
(4). In this case an orange complex [RuCl2(PPh3)2(κ2N,NЈ-apy)]
(12) was formed. This complex appears to be the first isol-
ated and fully characterized complex containing a κ2N,NЈ-co-
ordinated apy ligand. While the NMR spectra are unremark-
able, crystals suitable for a single-crystal X-ray diffraction
study could be grown and the results confirm the κ2N,NЈ co-
ordination mode of apy. An ORTEP plot of the Ru complex of
the solvate 12ؒCHCl3 is shown in Fig. 4 with selected bond
distances and angles given in the figure legend. The crystals of
12ؒCHCl3 contain discrete [RuCl2(PPh3)2(κ2N,NЈ-apy)] units
Selected bond distances and angles are reported in the figure
legend. The Cp ligands are in mutual cis configuration. The apy
Scheme 3
Fig. 3 Structural view of [RuCp(µ3-dapy)]2(PF6)2 (11) (50% ellipsoids;
PF6Ϫ and aromatic H atoms omitted for clarity). Selected bond lengths
(Å) and angles (Њ): Ru(1)–C(1–5)av 2.197(2), Ru(2)–C(6–10)av 2.203(2),
Ru(1)–Ru(2) 2.652(1), Ru(1)–N(1) 2.105(2), Ru(1)–N(2) 2.071(2),
Ru(2)–N(3) 2.091(2), Ru(2)–N(4) 2.087(2); N(1)–Ru(1)–N(2) 63.9(1),
N(3)–Ru(2)–N(4) 63.9(1), Ru(1)–N(2)–Ru(2) 79.9(1), Ru(1)–N(4)–
Ru(2) 79.3(1), N(2)–Ru(1)–N(4) 93.4(1), N(2)–Ru(2)–N(4) 93.2(1).
Fig. 4 Structural view of [RuCl2(PPh3)2(κ2N,NЈ-apy)]ؒCHCl3 (12ؒ
CHCl3) (40% ellipsoids; aromatic H atoms and solvent omitted for
clarity). Selected bond lengths (Å) and angles (Њ): Ru–P(1) 2.287(2),
Ru–P(2) 2.296(2), Ru–Cl(1) 2.423(1), Ru–Cl(2) 2.412(1), Ru–N(1)
2.151(4), Ru–N(2) 2.212(4); Cl(1)–Ru–Cl(2) 162.3(1), N(1)–Ru–N(2)
62.3(2), P(1)–Ru–P(2) 100.1(6), N(2)–Ru–Cl(1) 82.8(1), N(2)–Ru–Cl(2)
79.7(1).
D a l t o n T r a n s . , 2 0 0 3 , 2 3 2 9 – 2 3 3 4
2331

View Article Online
with the metal in a severely distorted octahedral environment
featuring trans chloro ligands. The Cl(1)–Ru–Cl(2) angle is
162.3(1)Њ. The apy ligand forms a distorted four-membered ring
system with a N(1)–Ru–N(2) angle of 62.3(2)Њ. The two PPh3
ligands are inequivalent, one being trans to N(py) and one trans
to N(NH2) of the apy ligand. This appears to be the first
example of a complex showing this particular bonding mode of
apy without needing any specific precautions. This result lends
further support to a recent suggestion16 that the ruthenium
complex-controlled catalytic N-mono and N,N-dialkylation of
apy with alcohols proceeds via κ2N,NЈ-apy ligated species.
8.47 (d, JHH = 6.12 Hz, 1H, py6), 7.50 (ddd, JHH1 = 8.32,
JHH2 = 7.17, JHH3 = 1.43 Hz, 1H, py4), 6.80 (d, JHH = 8.03 Hz,
1H, py3), 6.55 (ddd, JHH1 = 6.88, JHH2 = 6.50, JHH3 = 0.76 Hz,
1H, py5), 6.12 (s, 2H, NH2), 4.62 (s, 5H, Cp), 2.66 (d,
JHH = 1.53 Hz, 3H, NCCH3), 1.49 (d, JHH = 1.53 Hz, 9H,
PMe3).13C{1H} NMR (δ, acetone-d6, 20 ЊC): 161.2 (1C, py2),
152.0 (1C, py6), 137.9 (1C, py4), 128.0 (JCP = 9.7 Hz, 1C,
NCCH3), 113.7 (1C, py3), 109.8 (1C, py5), 74.3 (JCP = 2.3 Hz,
5C, Cp), 17.8 (JCP = 28.0 Hz, 3C, PMe3), 4.2 (1C, NCCH3).
31P{1H} NMR (δ, acetone-d6, 20 ЊC): 4.9 (PMe3), Ϫ144.3
(1JPF = 707.7 Hz, PF6).
[RuCp(PPh3)(CH3CN)(ꢀ1N-apy)]PF6 (5c). This compound
was prepared analogously to 5a using 2b (200 mg, 0.305 mmol)
and apy (29 mg, 0.305 mmol) as the starting materials. Yield:
189 mg (87%). Found: C, 50.68; H, 4.19. C30H29F6N3P2Ru
Conclusion
The diverse bonding modes available make 2-aminopyridine a
highly fascinating ligand in transition metal chemistry. The
presence of the amino group in the ortho position not only
introduces chelating ability but beyond this delicately modifies
the relative stabilities of nitrogen(N)-bonded and π-bonded
pyridines. The π-donor property of the amine group tends to
increase the electron availability in the aromatic ring, thereby
providing a driving force for π-complexation, and furthermore
enhances the donor strength of the pyridine nitrogen. Bulky
substituents sterically hinder the nitrogen nonbonding electrons
from coordination. In this contribution, we have prepared and
structurally characterized, for the first time, complexes contain-
ing a κ2N,NЈ- and η6-coordinated apy ligands, respectively.
1
requires C, 50.85; H, 4.12%. H NMR (δ, acetone-d6, 20 ЊC):
8.31 (d, JHH = 5.79 Hz, 1H, py6), 7.59–7.03 (m, 16H, PPh3, py4),
6.54 (d, JHH = 8.53 Hz, 1H, py3), 6.37 (t, JHH = 5.94 Hz, 1H,
py5), 6.11 (s, 2H, NH2), 4.66 (s, 5H, Cp), 2.11 (d, JHH = 1.53 Hz,
3H, NCCH3). 13C{1H} NMR (δ, acetone-d6, 20 ЊC): 161.8 (1C,
py2), 152.9 (1C, py6), 137.7 (1C, py4), 134.2 (JCP = 40.6 Hz, 3C,
Ph1), 133.2 (JCP = 10.6 Hz, 6C, Ph2,6), 131.8 (JCP = 9.7 Hz, 1C,
NCCH3), 130.0 (JCP = 2.2 Hz, 3C, Ph4), 128.5 (JCP = 9.3 Hz, 6C,
Ph3,5), 113.0 (1C, py3), 110.0 (1C, py5), 75.9 (JCP = 2.2 Hz, 5C,
Cp), 2.8 (1C, NCCH3). 31P{1H} NMR (δ, acetone-d6, 20 ЊC):
49.1 (PPh3), Ϫ144.2 (1JPF = 707.8 Hz, PF6).
[RuCp(CO)(ꢀ1N-apy)(CH3CN)]PF6 (5d). This compound
was prepared analogously to 5a using 3 (100 mg, 0.237 mmol)
and apy (23 mg, 0.237 mmol) as the starting materials. Yield:
89 mg (87%). Found: C 33.01; H 2.87. C13H14F6N3OPRu
Experimental
General
All manipulations were performed under an inert atmosphere
of argon by using Schlenk techniques. All chemicals were
standard reagent grade and used without further purification.
The solvents were purified according to standard procedures.17
The deuterated solvents were purchased from Aldrich and dried
over 4 Å molecular sieves. [RuCp(CH3CN)3]PF6 (1),18 [RuCp-
1
requires C, 32.92; H, 2.97%. H NMR (δ, acetone-d6, 20 ЊC):
8.26 (dd, JHH1 = 6.12, JHH2 = 1.04 Hz, 1H, py6), 7.54 (ddd,
JHH1 = 8.57, JHH2 = 7.06, JHH3 = 1.60 Hz, 1H, py4), 6.77 (d,
JHH = 8.48 Hz, 1H, py3), 6.60 (ddd, JHH1 = 6.88, JHH2 = 6.31,
JHH3 = 0.94 Hz, 1H, py5), 5.23 (s, 5H, RuCp), 6.15 (s, 2H, NH2),
2.44 (s, 3H, NCCH3). 13C{1H} NMR (δ, acetone-d6, 20 ЊC):
202.0 (1C, CO), 162.9 (1C, py2), 154.3 (1C, py6), 140.2 (1C, py4),
131.0 (1C, NCCH3), 115.0 (1C, py3), 112.0 (1C, py5), 83.5 (s, 5C,
RuCp), 3.7 (s, 1C, NCCH3).
(PMe3)(CH3CN)2]PF6
(2a),19
[RuCp(PPh3)(CH3CN)2]PF6
(2b),19 [RuCp(CO)(CH3CN)2]PF6 (3)18 and [RuCl2(PPh3)3] (4)20
were prepared according to the literature. H, 13C{1H} and
1
31P{1H} NMR spectra were recorded on a Bruker AVANCE-
250 spectrometer and were referenced to SiMe4 and H3PO4
[RuCp(᎐C(Ph)(ꢁ3-CHC(Ph)CHPMe )]PF (6). To a solution
᎐
3
6
(85%), respectively. H and 13C{1H} NMR signal assignments
1
᎐
of 5b (50 mg, 0.096 mmol) in acetone (4 mL) HC᎐CPh (10.5
᎐
were confirmed by H-COSY, DEPT-135 and HMQC(1H–13C)
1
µL, 0.096 mmol) was added. After the mixture was stirred at
room temperature for 4 h, the solvent was removed under vac-
uum and the resulting dark-red solid was collected on a glass
frit and washed twice with diethyl ether (10 mL). Yield: 47 mg
(83%). The NMR data are in agreement with those of an
authentic sample reported in the literature.21
experiments.
Syntheses
[RuCp(ꢀ1N-apy)(CH3CN)2]PF6 (5a). To a solution of 1
(200 mg, 0.461 mmol) in CH3NO2 (5 mL) 2-aminopyridine
(apy) (44 mg, 0.461 mmol) was added. After the mixture was
stirred at room temperature for 4 h, the solvent was removed
under vacuum and the resulting yellow solid was collected on a
glass frit and washed twice with diethyl ether (10 mL). Yield:
171 mg (76%). Found: C 34.42; H 3.59. C14H17F6N4PRu
[RuCp(PPh )(᎐C(CH )PhNHpy)]PF (7). To a solution of 5c
᎐
3
2
6
᎐
(80 mg, 0.119 mmol) in CH Cl (4 mL) HC᎐CPh (13.1 µL,
᎐
2
2
0.119 mmol) was added. After the mixture was stirred at room
temperature for 4 h, the solvent was removed under vacuum
and the resulting brown solid was collected on a glass frit and
washed twice with diethyl ether (10 mL). Yield: 73 mg (78%).
Found: C 55.98; H 4.22. C36H32F6N2P2Ru requires C, 56.18; H,
1
requires C, 34.50; H, 3.52%. H NMR (δ, CD2Cl2, 20 ЊC):
8.24 (dd, JHH1 = 5.94, JHH2 = 1.37 Hz, 1H, py6), 7.46 (ddd,
JHH1 = 8.45, JHH2 = 6.93, JHH3 = 1.60 Hz, 1H, py4), 6.71 (d,
JHH = 8.22 Hz, 1H, py3), 6.60 (ddd, JHH1 = 6.85, JHH2 = 6.24,
JHH3 = 0.91 Hz, 1H, py5), 5.64 (s, 2H, NH2), 4.40 (s, 5H, Cp),
2.42 (s, 6H, NCCH3). 13C{1H} NMR (δ, CD2Cl2, 20 ЊC): 161.0
(1C, py2), 152.0 (1C, py6), 138.0 (1C, py4), 126.5 (2C, NCCH3),
113.4 (1C, py3), 110.2 (1C, py5), 68.7 (5C, Cp), 3.8 (2C,
NCCH3).
1
4.19%. H NMR (δ, acetone-d6, 20 ЊC): 12.09 (br s, 1H, NH),
9.14 (d, JHH = 5.79 Hz, 1H, py6), 7.82–7.07 (m, 21H, PPh3, Ph,
py4), 6.99 (ddd, JHH1 = 7.31, JHH2 = 5.94, JHH3 = 1.37 Hz, 1H,
py5), 6.85 (d, JHH = 8.53 Hz, 1H, py3), 4.99 (d, JHH = 0.30 Hz,
5H, RuCp), 5.04 (d, JHH = 16.1 Hz, 1H, CH2), 4.57 (d,
JHH = 15.8 Hz, 1H, CH2). 13C{1H} NMR (δ, acetone-d6, 20 ЊC):
275.7 (JCP = 10.8 Hz, 1C, ᎐C), 156.7 (1C, py2), 155.2
᎐
[RuCp(PMe3)(ꢀ1N-apy)(CH3CN)]PF6 (5b). This compound
was prepared analogously to 5a using 2a (200 mg, 0.426 mmol)
and apy (41 mg, 0.426 mmol) as the starting materials. Yield:
158 mg (71%). Found: C 34.58; H 4.40. C15H23F6N3P2Ru
(JCP = 1.84 Hz, 1C, py6), 137.1 (1C, py4), 136.1 (1C, Ph1), 133.0
1
(JCP = 11.5 Hz, 6C, PPh32,6), 131.8 (JCP = 46.5 Hz, 3C, PPh3 ),
4
130.4 (JCP = 2.0 Hz, 3C, PPh3 ), 129.9 (2C, Ph2,6), 129.0 (2C,
Ph3,5), 128.5 (JCP = 10.1 Hz, 6C, PPh33,5), 128.5 (1C, Ph4), 119.8
(1C, py3), 114.0 (1C, py5), 83.7 (JCP = 1.4 Hz, 5C, RuCp), 56.6
1
requires C, 34.49; H, 4.44%. H NMR (δ, acetone-d6, 20 ЊC):
D a l t o n T r a n s . , 2 0 0 3 , 2 3 2 9 – 2 3 3 4
2332

View Article Online
Table 1 Crystallographic data for 9, 10, 11 and 12ؒCHCl3
9
10
11
12ؒCHCl3
Formula
Mw
Crystal system
Space group
a/Å
b/Å
c/Å
C12H15F6N2PRu
433.30
Monoclinic
P21/n (no. 14)
9.654(1)
12.595(2)
12.390(2)
C13H16F6NPRu
432.31
Monoclinic
P21 (no. 4)
7.082(1)
20.162(4)
10.718(2)
C20H20F12N4P2Ru2
808.48
C42H37Cl5N2P2Ru
910.00
Orthorhombic
Pbca (no. 61)
11.215(2)
22.814(3)
31.409(4)
Triclinic
¯
P1 (no. 2)
9.166(1)
10.224(1)
15.354(2)
88.201(3)
84.110(3)
64.720(3)
1294.1(3)
2
α/Њ
β/Њ
101.505(2)
100.217(3)
γ/Њ
V/Å3
1476.4(3)
4
1506.1(5)
4
8036(2)
8
Z
T /K
173(2)
1.232
30
123(2)
1.205
30
123(2)
1.397
30
173(2)
0.836
25
µ(Mo-Kα)/mmϪ1
θmax/Њ
Total rflns.
Indep. rflns.
Parameters
Rint
R1 (all data)
wR2 (all data)
15003
4228
210
0.020
0.030
0.063
22481
8520
401
0.040
0.057
0.108
9552
6540
370
0.011
0.024
0.052
35553
7073
412
0.135
0.110
0.132
R1 = Σ||Fo| Ϫ |Fc||/Σ|Fo|, wR2 = [Σ(w(Fo2 Ϫ Fc2)2)/Σ(w(Fo )2)] .
2
½
(1C, CH2). 31P{1H} NMR (δ, acetone-d6, 20 ЊC): 53.8 (PPh3),
Ϫ144.2 (1JPF = 717.0 Hz, PF6).
stirring for 10 h the solvent was removed under vacuum, the
resulting green solid was collected on a glass frit and washed
twice with pentane (10 mL). Yield: 235 mg (84%). Found: C
29.64; H 2.56. C20H20F12N4P2Ru2 requires C, 29.71; H, 2.49%.
1H NMR (δ, acetone-d6, 20 ЊC): 11.75 (br s, 2H, NH), 7.85
(dt, JHH1 = 8.03, JHH2 = 1.91 Hz, 2H, py6), 7.59 (dd, JHH = 4.78,
JHH2 = 0.57 Hz, 2H, py4), 7.12 (d, JHH = 8.03 Hz, 2H, py3), 6.87
(ddd, JHH1 = 7.36, JHH2 = 5.26, JHH3 = 0.48 Hz, 2H, py5), 6.01 (s,
10H, Cp). 13C{1H} NMR (δ, acetone-d6, 20 ЊC): 172.1 (2C, py2),
151.7 (2C, py6), 140.7 (2C, py4), 120.3 (2C, py3), 118.0 (2C, py5),
91.0 (10C, Cp).
[RuCp(CO)(᎐C(CH )PhNHpy)]PF (8). This compound was
᎐
2
6
prepared analogously to 7 using 5d (80 mg, 0.169 mmol) and
᎐
HC᎐CPh (18.5 µL, 0.169 mmol) as the starting materials. Yield:
᎐
76 mg (84%). Found: C 46.58; H 3.23. C19H17F6N2OPRu
requires C, 46.62; H, 3.20%. 1H NMR (δ, CD3NO2, 20 ЊC): 8.75
(d, JHH = 5.79 Hz, 1H, py6), 8.04 (t, JHH = 7.46 Hz, 1H, py4),
7.74 (d, JHH = 8.22 Hz, 1H, py3), 7.50–7.24 (m, 6H, py5, Ph),
5.31 (s, 5H, RuCp), 5.17 (d, JHH = 13.7 Hz, 1H, CH2), 4.82 (d,
JHH = 12.2 Hz, 1H, CH2). 13C{1H} NMR (δ, CD3NO2, 20 ЊC):
275.9 (1C, ᎐C), 196.4 (1C, CO), 156.7 (1C, py2), 156.2 (1C, py6),
[RuCl2(PPh3)2(ꢀ2N,NЈ-apy)] (12). A solution of 4 (300 mg,
0.313 mmol) and apy (30 mg, 0.313 mmol) in CH2Cl2 (10 mL)
was stirred at room temperature for 4 h. After removal of
the solvent under reduced pressure, the orange product was
washed three times with diethyl ether (45 mL), and dried under
vacuum. Yield: 190 mg (77%). Found: C, 62.32; H, 4.52.
C41H36Cl2N2P2Ru requires C, 62.28; H, 4.59%. 1H NMR
(δ, DMSO-d6, 20 ЊC): 7.54–6.67 (m, 34H, PPh3, py), 3.89 (s, 2H,
NH2). 13C{1H} NMR (δ, dmso-d6, 20 ЊC): 160.2 (1C, py2), 148.1
(1C, py6), 137.4 (1C, py4), 135.5 (JCP = 9.2 Hz, 6C, Ph4), 133.7
(JCP = 44.1 Hz, 6C, Ph1), 133.7 (JCP = 19.8 Hz, 12C, Ph2,6), 129.3
(JCP = 17.0 Hz, 12C, Ph3,5), 112.2 (1C, py3), 108.4 (1C, py5).
31P{1H} NMR (δ, DMSO-d6, 20 ЊC): 49.9 (PPh3).
᎐
140.3 (1C, py4), 134.9 (1C, Ph1), 130.0 (2C, Ph2,6), 129.0 (2C,
Ph3,5), 127.7 (1C, Ph4), 121.9 (1C, py3), 115.2 (1C, py5), 85.7 (5C,
RuCp), 73.2 (1C, CH2).
[RuCp(ꢁ6-dmapy)]PF6 (9). To a solution of 1 (200 mg, 0.461
mmol) in CH2Cl2 (5 mL) 2-N,N-dimethylaminopyridine
(dmapy) (57.2 µL, 0.461 mmol) was added. After the mixture
was stirred at room temperature for 4 h, the solvent was
removed under vacuum and the resulting white solid was
collected on a glass frit and washed twice with diethyl ether
(10 mL). Yield: 162 mg (81%). Found: C 33.31; H 3.39. C12H15-
F6N2PRu requires C, 33.23; H, 3.46%. 1H NMR (δ, acetone-d6,
20 ЊC): 6.99 (t, 1H, py6), 6.39–6.22 (m, 3H, py), 5.51 (s, 5H, Cp),
3.07 (s, 6H, NMe2). 13C{1H} NMR (δ, acetone-d6, 20 ЊC): 136.7
(1C, py2), 99.1 (1C, py6), 87.5 (1C, py4), 81.2 (1C, py3), 79.6 (5C,
Cp), 63.4 (1C, py5), 36.9 (2C, NMe2).
Computational details
All calculations were performed using the Gaussian98 software
package on the Silicon Graphics Origin 2000 of the Vienna
University of Technology.22 The geometry and energy of the
model complexes and the transition states were optimized at the
B3LYP level23 with the Stuttgart/Dresden ECP (SDD) basis
set24 to describe the electrons of the Ru atom. For the H, C and
N atoms the 6-31g** basis set was employed.25 A vibrational
analysis was performed to confirm that the structures of
the model compounds have no imaginary frequency. The geom-
etries were optimized without constraints (C1 symmetry).
[RuCp(ꢁ6-C6H5NMe2)]PF6 (10). This compound was pre-
pared analogously to 9 using 1 (100 mg, 0.230 mmol) and N,N-
dimethylaniline (29.2 µL, 0.230 mmol) as the starting materials.
Yield: 90 mg (90%). Found: C 36.15; H 3.77. C13H16F6NPRu
1
requires C, 36.12; H, 3.73%. H NMR (δ, acetone-d6, 20 ЊC):
6.11–5.88 (m, 5H, Ph), 5.40 (s, 5H, Cp), 2.94 (s, 6H, NMe2).
13C{1H} NMR (δ, acetone-d6, 20 ЊC): 127.6 (1C, Ph1), 83.4 (2C,
Ph2,6), 80.6 (1C, Ph4), 78.0 (5C, Cp), 68.0 (2C, Ph3,5), 39.2 (2C,
NMe2).
X-Ray crystallography
[RuCp(ꢂ3-dapy)]2(PF6)2 (11). To a solution of 1 (300 mg,
0.691 mmol) in acetone (10 mL) apy (66 µL, 0.691 mmol) was
added. After the mixture was stirred at room temperature
for 10 min, air was bubbled through the solution for 5 min,
whereupon the colour changed from yellow to dark green. After
Crystals of 9, 10 and 11 were obtained by diffusion of diethyl
ether into acetone solutions, whereas crystals of 12ؒCHCl3
were obtained by diffusion of Et2O into a CHCl3 solution.
Crystal data and experimental details are given in Table 1.
X-ray data were collected on a Bruker Smart CCD area
D a l t o n T r a n s . , 2 0 0 3 , 2 3 2 9 – 2 3 3 4
2333

View Article Online
13 E. Rüba, K. Mereiter, R. Schmid, V. N. Sapunov, K. Kirchner,
H. Schottenberger, M. J. Calhorda and L. F. Veiros, Chem. Eur. J.,
2002, 8, 3948.
detector diffractometer (graphite monochromated Mo-Kα
radiation, λ = 0.71073 Å, 0.3Њ ω scan frames, Bruker Kryoflex
cooling unit). Corrections for crystal decay and for absorption
were applied.26 The structures were solved by direct methods
using the program SHELXS97.27 Structure refinement on F 2
was carried out with program SHELXL97.27 All non-hydrogen
atoms were refined anisotropically. Most hydrogen atoms were
inserted in idealized positions and were refined riding with the
atoms to which they were bonded. Some crucial hydrogen
atoms were refined in x, y and z. Compound 10 contains
two crystallographically different, but stereochemically similar
formula moieties in the asymmetric unit of a definitely acen-
tric unit cell. In 12ؒCHCl3 the solvent is disordered, the
composition is idealized, and the solvent was taken into
account with procedure SQEEZE of program PLATON;28 two
N–H ؒ ؒ ؒ Cl(Ru) hydrogen bonds with N ؒ ؒ ؒ Cl = 3.374(5) Å
link each two Ru complexes in pairs.
14 For related amino and amido carbene complexes see: (a) C. M.
Standfest-Hauser, K. Mereiter, R. Schmid and K. Kirchner,
Organometallics, 2002, 21, 4893; (b) C. Slugovc, K. Mereiter,
R. Schmid and K. Kirchner, Organometallics, 1998, 17, 827.
15 (a) M. Nishio, H. Matsuzaka, Y. Mizobe and M. Hidai,
Organometallics, 1996, 15, 965, and references therein; (b) Y.
Takagi, H. Matsuzaka, Y. Ishii and M. Hidai, Organometallics,
1997, 16, 4445.
16 Y. Watanabe, Y. Morisaki, T. Kondo and T. Mitsudo, J. Org. Chem.,
1996, 61, 4214.
17 D. D. Perrin and W. L. F. Armarego, Purification of Laboratory
Chemicals, Pergamon, New York, 3rd edn., 1988.
18 T. P. Gill and K. R. Mann, Organometallics, 1982, 1, 485.
19 E. Rüba, W. Simanko, K. Mauthner, K. M. Soldouzi, C. Slugovc,
K. Mereiter, R. Schmid and K. Kirchner, Organometallics, 1999, 18,
3843.
20 T. A. Stephenson and G. Wilkinson, J. Inorg. Nucl. Chem., 1966, 28,
CCDC reference numbers 205216–205219.
945.
21 K. Mauthner, K. M. Soldouzi, K. Mereiter, R. Schmid and
K. Kirchner, Organometallics, 1999, 18, 4681.
See http://www.rsc.org/suppdata/DT/b3/b302416d/ for crys-
tallographic data in CIF or other electronic format.
22 M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria,
M. A. Robb, J. R. Cheeseman, V. G. Zakrzewski, J. A. Montgomery
Jr., R. E. Stratmann, J. C. Burant, S. Dapprich, J. M. Millam,
A. D. Daniels, K. N. Kudin, M. C. Strain, O. Farkas, J. Tomasi,
V. Barone, M. Cossi, R. Cammi, B. Mennucci, C. Pomelli,
C. Adamo, S. Clifford, J. Ochterski, G. A. Petersson, P. Y. Ayala,
Q. Cui, K. Morokuma, D. K. Malick, A. D. Rabuck,
K. Raghavachari, J. B. Foresman, J. Cioslowski, J. V. Ortiz,
A. G. Baboul, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz,
I. Komaromi, R. Gomperts, R. L. Martin, D. J. Fox, T. Keith,
M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, C. Gonzalez,
M. Challacombe, P. M. W. Gill, B. Johnson, W. Chen, M. W. Wong,
J. L. Andres, C. Gonzalez, M. Head-Gordon, E. S. Replogle and
J. A. Pople, Gaussian 98, revision A.7; Gaussian, Inc., Pittsburgh,
PA, 1998.
23 (a) A. D. Becke, J. Chem. Phys., 1993, 98, 5648; B. Miehlich,
A. Savin, H. Stoll and H. Preuss, Chem. Phys. Lett, 1989, 157, 200;
(b) C. Lee, W. Yang and G. Parr, Phys. Rev. B, 1988, 37, 785.
24 (a) U. Haeusermann, M. Dolg, H. Stoll, H. Preuss, P. Schwerdtfeger
and R. M. Pitzer, Mol. Phys., 1993, 78, 1211; (b) W. Kuechle,
M. Dolg, H. Stoll and H. Preuss, J. Chem. Phys., 1994, 100, 7535;
(c) T. Leininger, A. Nicklass, H. Stoll, M. Dolg and P. Schwerdtfeger,
J. Chem. Phys., 1996, 105, 1052.
Acknowledgements
Financial support by the “Fonds zur Förderung der
wissenschaftlichen Forschung” (Project No. P14681-CHE) is
gratefully acknowledged.
References
1 E. Rüba, A. Hummel, K. Mereiter, R. Schmid and K. Kirchner,
Organometallics, 2002, 21, 4955.
2 D.-H. Lee, J. Chen, J. W. Faller and R. H. Crabtree, Chem.
Commun., 2001, 213.
3 C. E. F. Rickard, W. R. Roper, A. Williamson and L. J. Wright,
Organometallics, 2002, 21, 4862.
4 C. Soria Alvarez, A. D. Bond, D. Cave, M. E. G. Mosquera,
E. A. Harron, R. A. Layfield, M. McPartlin, J. M. Rawson,
P. T. Wodd and D. S. Wright, Chem. Commun., 2002, 2980.
5 R. Kempe, Eur. J. Inorg. Chem., 2003, 791.
6 J. A. Cabeza, Eur. J. Inorg. Chem., 2002, 1559, and references
therein.
7 X. Xu, S. L. James, D. M. P. Mingos, A. J. P. White and D. J.
Williams, J. Chem. Soc., Dalton Trans., 2000, 3783.
8 R. H. Fish, H.-S. Kim and R. H. Fong, Organometallics, 1991, 10,
770.
9 (a) B. Chaudret and F. A. Jalon, J. Chem. Soc., Chem. Commun.,
1988, 711; (b) B. Chaudret, F. A. Jalon, M. Perez-Manrique,
F. Lahoz, F. J. Plou and R. Sanchez-Delgado, New J. Chem., 1990,
14, 331.
25 (a) A. D. McClean and G. S. Chandler, J. Chem. Phys., 1980, 72,
5639; (b) R. Krishnan, J. S. Binkley, R. Seeger and J. A. Pople,
J. Chem. Phys., 1980, 72, 650; (c) A. J. H. Wachters, J. Chem. Phys.,
1970, 52, 1033; (d ) P. J. Hay, J. Chem. Phys., 1977, 66, 4377;
(e) K. Raghavachari and G. W. Trucks, J. Chem. Phys., 1989, 91,
2457; ( f ) M. P. McGrath and L. Radom, J. Chem. Phys., 1991, 94,
511.
26 Bruker, Programs SMART, version 5.054; SAINT, version 6.2.9;
SADABS version 2.03; XPREP, version 5.1; SHELXTL, version
5.1. Bruker AXS Inc., Madison, WI, USA, 2001.
10 R. H. Fish, H. S. Kim and R. H. Fong, Organometallics, 1989, 8,
1375.
11 A. D. Hunter, L. Shilliday, W. S. Furey and M. J. Zaworotko,
Organometallics, 1992, 11, 1550.
12 J.-P. Djukic, F. Rose-Munch, E. Rose and J. Vaissermann, Eur. J.
Inorg. Chem., 2000, 1295.
27 G. M. Sheldrick, SHELX97: Program System for Crystal Structure
Determination, University of Göttingen, Germany, 1997.
28 A. L. Spek, PLATON, A Multipurpose Crystallographic Tool,
Utrecht University, Utrecht, The Netherlands, 2003.
D a l t o n T r a n s . , 2 0 0 3 , 2 3 2 9 – 2 3 3 4
2334