Synthesis and structural characterization of ruthenium π-arene and π-cyclodienyl complexes containing 1,4,7-trimethyl-1,4,7-triazacyclononane

Article abstract of DOI:10.1021/om970617y

The reaction between Ru(Me₃tacn)Cl₃ (Me₃tacn = 1,4,7-trimethyl-1,4,7-triazacyclononane) and silver trifluoromethanesulfonate in ethanol affords a green species: treatment with cyclohexa-1,3-diene gives [Ru(Me₃tacn)(η⁶-C₆H₆)] ²⁺ (1), while in the presence of zinc dust, reactions with 1-(trimethylsilyl)cyclopentadiene, 1-(trimethylsilyl)indene cyclohexa-13-diene, and cycloheptatriene yield [Ru(Me₃tacn)(η⁵-C₅H₅)] ⁺ (2), [Ru(Me₃tacn)(η⁵-C₉H₇)] ⁺ (3), [Ru(Me₃-tacn)((1-5-η)-C₆H₇)]⁺ (4), and [Ru(Me₃tacn)((1-5-η)-C₇H₉)]⁺ (5), respectively. X-ray diffraction studies of the [PF₆]^- salts of complexes 3-5 show that in each case the η⁵-bonded unsaturated hydrocarbon moiety is virtually planar.

Full text of DOI:10.1021/om970617y

Organometallics 1998, 17, 151-155
151
Syn th esis a n d Str u ctu r a l Ch a r a cter iza tion of Ru th en iu m
π-Ar en e a n d π-Cyclod ien yl Com p lexes Con ta in in g
1,4,7-Tr im eth yl-1,4,7-tr ia za cyclon on a n e
San-Ming Yang,† Michael Chi-Wang Chan,† Shie-Ming Peng,‡ and
Chi-Ming Che*,†
Departments of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, and
National Taiwan University, Taiwan, ROC
Received J uly 21, 1997X
The reaction between Ru(Me3tacn)Cl3 (Me3tacn ) 1,4,7-trimethyl-1,4,7-triazacyclononane)
and silver trifluoromethanesulfonate in ethanol affords a green species: treatment with
cyclohexa-1,3-diene gives [Ru(Me3tacn)(η6-C6H6)]2+ (1), while in the presence of zinc dust,
reactions with 1-(trimethylsilyl)cyclopentadiene, 1-(trimethylsilyl)indene, cyclohexa-1,3-diene,
and cycloheptatriene yield [Ru(Me3tacn)(η5-C5H5)]+ (2), [Ru(Me3tacn)(η5-C9H7)]+ (3), [Ru(Me3-
tacn)((1-5-η)-C6H7)]+ (4), and [Ru(Me3tacn)((1-5-η)-C7H9)]+ (5), respectively. X-ray diffrac-
tion studies of the [PF6]- salts of complexes 3-5 show that in each case the η5-bonded
unsaturated hydrocarbon moiety is virtually planar.
(π-Polyenyl)ruthenium complexes occupy an increas-
ingly important role in organometallic chemistry, and
the reactivity of the (η6-arene)ruthenium fragment has
been extensively investigated.1 Substituted arenes with
appropriate leaving groups are activated toward nu-
cleophilic substitution, and this has found important
applications in peptide labeling and synthesis.2 Ac-
counts describing the formation of (η5-cyclohexadienyl)-
ruthenium complexes from η6-benzene derivatives have
F igu r e 1. Numbering of hydrogens in complexes 3-5
([Ru] ) Ru(Me3tacn)).
appeared.3 It has been suggested that the incorporation
of ancillary ligands such as benzene,1 cyclopentadienyl
anion,4 1,4,7-trithiacyclononane,5 tris(2-pyrazolyl)bo-
rate,6 and (2-pyridylethyl)(2-pyridylmethyl)methylamine7
can affect the electrophilicity of the coordinated arene,
which decreases as the electron-donating ability of the
ligand increases. The syntheses of (η6-benzene)ruthe-
nium complexes containing 1,4,7-triazacyclononane5
(tacn) and ammonia8 ligands respectively have been
reported, but their reactivities toward nucleophiles have
not been investigated because the amine hydrogens in
each case display low tolerance toward basic substrates.
We therefore focused on the formation of congeners
containing tertiary amine ligands and now describe the
preparation of (η6-arene)- and (η5-cyclodienyl)ruthenium
complexes containing 1,4,7-trimethyl-1,4,7-triazacy-
clononane (Me3tacn) and their reactivities toward nu-
cleophiles. The molecular structures of three new
derivatives are presented. The syntheses of cycloocta-
dienylruthenium species containing Me3tacn have been
reported.9
Exp er im en ta l Section
All reactions were carried out under a nitrogen atmosphere
using standard Schlenk techniques unless stated otherwise.
Ru(Me3tacn)Cl3,10 1-(trimethylsilyl)cyclopentadiene, and 1-(tri-
methylsilyl)indene11 were prepared according to literature
procedures. Cycloheptatriene (Aldrich) was distilled before
use. Silver trifluoromethanesulfonate (AgOTf) was obtained
from Aldrich. All solvents were reagent grade and were used
without further purification. 13C (67.5 MHz) and 1H (270 MHz)
NMR spectra were recorded on a J EOL 270 FT-NMR spec-
trometer with Me4Si as internal reference. The numbering of
hydrogens in 3-5 is given in Figure 1. Fast atom bombard-
ment (FAB) mass spectra were obtained on a Finnigan MAT
95 mass spectrometer with a 3-nitrobenzyl alcohol matrix.
Elemental analyses were performed by Butterworth Labora-
tory Ltd, Teddington, U.K.
† The University of Hong Kong.
‡ National Taiwan University.
X Abstract published in Advance ACS Abstracts, December 15, 1997.
(1) Albers, M. O.; Robinson, D. J .; Singleton, E. Coord. Chem. Rev.
1987, 79, 1.
(2) Kra¨mer, R. Angew. Chem., Int. Ed. Engl. 1996, 35, 1197.
(3) (a) J ones, D.; Pratt, L.; Wilkinson, G. J . Chem. Soc. 1962, 4458.
(b) Grundy, S. L.; Maitlis, P. M. J . Chem. Soc., Chem. Commun. 1982,
379.
(4) Moriarty, R. M.; Gill, U. S.; Ku, Y. Y. J . Organomet. Chem. 1988,
350, 157.
(5) Schro¨der, M. Pure Appl. Chem. 1988, 60, 517.
(6) Bhambri, S.; Tocher, D. A. Polyhedron 1996, 15, 2763.
(7) Shirin, Z.; Mukherjee, R.; Richardson, J . F.; Buchanan, R. M. J .
Chem. Soc., Dalton Trans. 1994, 465.
(9) Yang, S. M.; Cheng, W. C.; Cheung, K. K.; Peng, S. M.; Che, C.
M. J . Chem. Soc., Dalton Trans. 1995, 227.
(10) Neubold, P.; Wieghardt, K.; Nuber, B.; Weiss, J . Inorg. Chem.
1989, 28, 459.
(11) Kraihanzel, C. S.; Losee, M. L. J . Am. Chem. Soc. 1968, 90,
4701.
(8) Hung, Y.; Kung, W. J .; Taube, H. Inorg. Chem. 1981, 20, 457.
S0276-7333(97)00617-1 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 01/19/1998

152 Organometallics, Vol. 17, No. 2, 1998
Ta ble 1. Cr ysta llogr a p h ic Da ta for Com p lexes 3-5
Yang et al.
3
4
5
formula
mol wt
C
18H28N3RuPF6
C15H28N3RuPF6
496.44
C16H30N3RuPF6
510.46
532.47
cryst syst
space group
cryst dimens/mm3
a/Å
b/Å
c/Å
monoclinic
P21/c
orthorhombic
Pnma
orthorhombic
Pca21
0.20 × 0.35 × 0.50
7.9977(12)
23.072(3)
11.9401(16)
106.856(12)
2108.6(5)
1075
0.25 × 0.25 × 0.40
16.2680(15)
14.8099(18)
8.0606(16)
-
0.25 × 0.25 × 0.30
16.5735(20)
8.1781(11)
14.6570(18)
-
â/deg
U/Å3
1942.0(5)
1003
1986.6(4)
1035
F(000)
Z
4
4
4
Dc/g cm-3
1.677
8.724
50
3022 (I g 2σ(I))
263
0.046, 0.052
1.48
1.698
9.325
55
1863 (I g 2σ(I))
128
0.050, 0.054
1.13
1.707
9.115
55
1795 (I g 2σ(I))
244
0.034, 0.035
2.02
µ/cm-1
2θmax/deg
no. of rflns used
no. of variables
R, Rw
GOF
residual F/e Å-3
(∆/σ)max
+0.96 to -0.85
0.01
+1.45 to -0.72
0.01
+0.41 to -0.47
0.05
Syn th esis. [Ru (Me3ta cn )(η6-C6H6)](OTf)2 (1). A mixture
of Ru(Me3tacn)Cl3 (0.1 g, 0.26 mmol) and AgOTf (0.23 g, 0.87
mmol) in absolute ethanol (30 cm3) was refluxed for 2 h. After
filtration, 1,3-cyclohexadiene (0.50 g, 6.25 mmol) was added
to the green solution, which was refluxed for 18 h. The
resultant yellow microcrystalline solid was collected, washed
with diethyl ether, and air-dried (yield 0.1 g, 58%). Anal.
Found: C, 31.60; H, 4.17; N, 6.43. Calcd for C17H27N3O6F6-
RuS2: C, 31.48; H, 4.17; N, 6.48. 1H NMR (CD3OD): δ 6.04
(6H, s, C6H6), 3.62 (9H, s, NCH3), 2.94-3.06, 3.12-3.34 (12H,
m, NCH2-). 13C NMR (CD3OD): δ 59.9 (NCH3), 62.5 (NCH2-
), 88.3 (C6H6). FAB MS (102Ru): m/ z 500 [M+ - OTf], 351
[M+ - 2OTf].
mixture was refluxed for 18 h. Removal of zinc followed by
addition of NH4PF6 afforded a yellow microcrystalline solid
(yield 0.03 g, 23%). Anal. Found: C, 36.37; H, 5.78; N, 8.66.
Calcd for C15H28N3F6PRu: C, 36.29; H, 5.68; N, 8.46. 1H NMR
(CD2Cl2): δ 5.37 (1H, t, J ) 4.5 Hz, H3), 4.11 (3H, s, NCH3),
4.03 (2H, t, H2 and H4), 3.28-3.23, 3.13-3.08 (4H, m, NCH2-),
2.69-2.57 (14H, m, two NCH3 and NCH2-), 2.38-2.33 (1H,
dt, H6endo,
2J ) 13.1 Hz, 3J ) 6.0 Hz), 1.69-1.67 (2H, t, H1
and H5), 1.46-1.43 (1H, d, H6exo, 2J ) 13.1 Hz). 13C NMR (CD3-
CN): δ 89.9 (C3), 64.2 (C2 and C4), 61.1 (C1 and C5), 61-56
(NCH3 and NCH2-), 25.4 (C6). FAB MS (102Ru): m/ z 352 [M+
- PF6].
[Ru (Me3ta cn )((1-5-η)-C7H9)]P F 6 (5). In contrast to the
procedure used for 2, cycloheptatriene (0.5 g, 5.5 mmol) was
added instead and the mixture was refluxed for 7 days.
Removal of zinc followed by addition of NH4PF6 gave light
yellow microcrystals (yield 0.03 g, 22%). Anal. Found: C,
37.36; H, 5.89; N, 8.55. Calcd for C16H30N3F6PRu: C, 37.65;
H, 5.92; N, 8.23. 1H NMR ((CD3)2CO): δ 5.42 (1H, t, J ) 5.6
Hz, H3), 4.28 (2H, dd, J ) 5.6 and 8.5 Hz, H2 and H4), 3.97
(3H, s, NCH3), 3.22-3.42 (14H, m, NCH2-, H1 and H5), 2.83
(6H, s, NCH3), 1.95, 0.82 (4H, m, H6 and H7). 13C NMR ((CD3)2-
CO): δ 90.8 (C3), 77.8 (C2 and C4), 61.4 (C1 and C5), 60.5, 59.8,
59.3, 54.3, 53.6 (NCH3 and NCH2-), 28.8 (C6 and C7). FAB
MS (102Ru): m/ z 366 [M+ - PF6].
[Ru (Me3ta cn )(η5-C5H5)]P F 6 (2). A mixture of Ru(Me3-
tacn)Cl3 (0.1 g, 0.26 mmol) and AgOTf (0.23 g, 0.87 mmol) in
absolute ethanol (30 cm3) was refluxed for 2 h. After filtration,
zinc powder (1 g) and 1-(trimethylsilyl)cyclopentadiene (0.5 g,
3.5 mmol) were added to the green solution. The resultant
mixture was refluxed for 12 h and then filtered and concen-
trated to ca. 5 cm3. Addition of NH4PF6 resulted in the
precipitation of a yellow-orange solid, which was recrystallized
by diffusion of diethyl ether into an acetone solution (yield 0.11
g, 86%). Anal. Found: C, 34.95; H, 5.31; N, 8.80. Calcd for
C
14H26N3F6PRu: C, 34.86; H, 5.43; N, 8.71. 1H NMR ((CD3)2-
CO): δ 3.92 (5H, s, C5H5), 3.57 (9H, s, NCH3), 3.18-3.07, 2.95-
2.86 (12H, m, NCH2-). 13C NMR ((CD3)2CO): δ 57.5 (NCH3),
Str u ctu r a l Deter m in a tion s. Crystallographic data for
compounds 3-5 are listed in Table 1 (see Supporting Informa-
tion for details). Diffraction data were collected at 298 K on
an Enraf-Nonius diffractometer with graphite-monochroma-
tized Mo KR radiation (λ ) 0.7107 Å) using the θ-2θ scan
mode (three standard reflections every 3600 s, <2% decay).
The structures were solved by heavy-atom Patterson methods
and expanded using Fourier techniques and refinement by full-
matrix least squares using the NRCVAX programs.12 All
non-H atoms in each structure were refined anisotropically.
For complex 4, the space group is Pnma and the atoms ending
59.4 (NCH2-), 65.4 (C5H5). FAB MS (102Ru): m/ z 338 [M+
PF6].
-
[Ru (Me3ta cn )(η5-C9H7)]P F 6 (3). The procedure is similar
to that for complex 2, except 1-(trimethylsilyl)indene (1 g, 5.3
mmol) was used. The mixture was refluxed for 3 days to give
an orange solution. Removal of zinc followed by addition of
NH4PF6 afforded 3 as red-brown microcrystals (yield 0.05 g,
36%). Anal. Found: C, 40.43; H, 5.07; N, 7.80. Calcd for
C18H28N3F6PRu: C, 40.60; H, 5.30; N, 7.89. 1H NMR ((CD3)2-
CO): δ 7.56-7.52, 7.10-7.16 (4H, two dd, H4/4′ and H5/5′, J 4,5
) 6.59 Hz, J 4,5′ ) 3.17 Hz), 4.64-4.62 (1H, t, H2, J 1,2 ) 2.34
Hz), 4.57-4.55 (2H, d, H1/1′, J 1,2 ) 2.34 Hz), 3.52 (9H, s, NCH3),
2.87-2.73 (12H, m, NCH2-). 13C NMR ((CD3)2CO): δ 128.9,
126.0 (C4 and C5), 92.9 (C3), 86.8 (C2), 61.0 (NCH2-), 59.1
(NCH3), 51.7 (C1). FAB MS (102Ru): m/ z 388 [M+ - PF6].
[Ru (Me3ta cn )((1-5-η)-C6H7)]P F 6 (4). Meth od A. Com-
plex 1 (0.1 g, 0.14 mmol) was dissolved in absolute methanol
(10 cm3) and NaBH4 (0.1 g, 2.6 mmol) was added slowly over
0.5 h. The mixture was stirred for 2 h and then concentrated.
Addition of NH4PF6 yielded 4 as a yellow solid (yield 0.06 g,
78%).
1
in “a” have coordinates at x, /2 - y, z.
Resu lts a n d Discu ssion
A series of η6-arene and η5-cyclodienyl complexes have
been prepared using the ruthenium(III) precursor
Ru(Me3tacn)Cl3, as summarized in Scheme 1. Interac-
tion between Ru(Me3tacn)Cl3 and 3 equiv of AgOTf in
absolute ethanol yielded a green solution (labeled X),
Meth od B. In contrast to the procedure used for 2, 1,3-
cyclohexadiene (0.5 g, 6.25 mmol) was added instead and the
(12) Cable, E. J .; Le Page, Y.; Charland, J . P.; Lee, F. L.; White, P.
S. J . Appl. Crystallogr. 1989, 22, 384.

Ru π-Arene and π-Cyclodienyl Complexes
Organometallics, Vol. 17, No. 2, 1998 153
Sch em e 1
and results of gravimetric analysis revealed the forma-
tion of 3 molar equiv of AgCl. Attempts to characterize
the resultant green species were unsuccessful, but its
reactivity suggests that it is effectively a “RuIII(Me3-
tacn)” equivalent.
dination of 1,3-cyclohexadiene to the metal center.
Attempts to synthesize [Ru(Me3tacn)(η6-anisole)]2+ and
[Ru(Me3tacn)(η6-p-cymene)]2+ by reacting the solution
X with 1-methoxycyclohexa-1,3-diene and R-phelland-
rene respectively were unsuccessful. We suggest that
the steric repulsion between the methyl groups of Me3-
tacn and the bulky substituents on each 1,3-diene
hinders their interaction with the ruthenium center, a
prerequisite for the dehydrogenation process.
In the presence of zinc powder, the aforementioned
solution X reacted with 1-(trimethylsilyl)cyclopenta-
diene and 1-(trimethylsilyl)indene to afford [Ru(Me3-
tacn)(η5-C5H5)]PF6 (2) and [Ru(Me3tacn)(η5-C9H7)]PF6
(3), respectively. However, no reaction was observed
with cyclopentadiene, indene, or 2,4-dimethylpenta-2,4-
diene in the presence of zinc. Cyclopentadienylsilicon
and -tin reagents have been extensively used as precur-
sors to η5-cyclopentadienyl complexes,16 e.g., CpSiMe3
reacts with ethanolic RuCl3 to give ruthenocene in 96%
yield.17 Cp*SiMe3 did not react with the solution X to
give [Ru(Me3tacn)(Cp*)]+ even after prolonged reflux in
the presence of zinc.
[Ru(Me3tacn)((1-5-η)-C6H7)]PF6 (4) was prepared in
moderate yield by the reduction of 1 in methanol using
NaBH4. The enhanced electrophilicity of the coordi-
nated benzene ring in 1 facilitates nucleophilic attack
by borohydride anions to afford the cyclohexadienyl
group. However, complex 1 did not react with sodium
methoxide or sodium dimethyl malonate in methanol.
These observations are in contrast to those for [RuL′-
(η6-C6H6)]2+ (L′ ) (2-pyridylethyl)(2-pyridylmethyl)-
methylamine), which reacts with OH- and CN- spe-
cies.18 Since nucleophilic attack occurs at the exo face
Reports on (η6-arene)ruthenium complexes containing
nitrogen donor ligands have appeared.5-8 Schro¨der and
co-workers prepared [(tacn)Ru(η6-arene)]2+ (arene )
C6H6, p-cymene) by reacting {Ru(η6-arene)Cl2}n with
tacn in ethanol, but the corresponding reaction with
Me3tacn gave intractable products.5 In addition, the
reaction of [(η6-C6H6)Ru(NCMe)3]2+ with Me3tacn in
ethanol did not yield the desired complex. A general
method for the preparation of [Cp*Ru(polyarene)]+
complexes is by treatment of [Cp*Ru(NCMe)3]+ with the
aromatic substrate.13 However, no reaction was ob-
served between [Ru(Me3tacn)(NCMe)3]2+ and benzene.
In this study, addition of 1,3-cyclohexadiene to the
generated green solution X afforded [Ru(Me3tacn)(η6-
C6H6)](OTf)2 (1) in moderate yield. Complex 1 is soluble
in acetone and methanol but insoluble in acetonitrile
and dichloromethane. Metathesis of 1 with other anions
(e.g. ClO4-, PF6-) in methanol yielded an insoluble solid
which hampered further characterization. The mech-
anism for the formation of 1 presumably involves
coordination of 1,3-cyclohexadiene to the ruthenium(III)
center followed by dehydrogenation to yield the [(η6-
C6H6)RuII] moiety; this pathway is related to the
preparation of {(η6-C6H6)RuCl2}2.14 The green solution
X did not react with benzene in the presence of zinc,
which is in accordance with the unsuccessful synthesis
of [(η6-C6H6)Ru(H2O)3]2+ from [Ru(H2O)6]2+ and C6H6.15
These observations reflect the importance in the coor-
(13) Koelle, U.; Wang, M. H. Organometallics 1990, 9, 195.
(14) Bennett, M. A.; Smith, A. K. J . Chem. Soc., Dalton Trans. 1974,
233.
(15) Koelle, U.; Weissschadel, C.; Englert, U. J . Organomet. Chem.
1995, 490, 101.
(16) (a) Abel, E. W.; Dunster, M. O.; Waters, A. J . Organomet. Chem.
1973, 49, 287. (b) Llina´s, G. H.; Mena, M.; Palacios, F.; Royo, P.;
Serrano, R. J . Organomet. Chem. 1988, 340, 37.
(17) Winter, C. H.; Pirzad, S.; Cao, D. H. J . Chem. Soc., Chem.
Commun. 1991, 1026.

154 Organometallics, Vol. 17, No. 2, 1998
Yang et al.
Ta ble 2. 1H NMR Ch em ica l Sh ifts of η5-C5H5
Liga n d s in Ru th en iu m Mixed -Sa n d w ich -Typ e
Com p lexes
complexes
δ
ref
[Ru(η5-C5H5)(Me3tacn)]PF6 (2)
[Ru(η5-C5H5)(η6-C6H6)]BF4
Ru(η5-C5H5)2
3.77,a 3.92b
5.37a
this work
23
24
25
25
25
26
27
28
29
29
29
4.58a
[Ru(η5-C5H5)(η6-C6Me6)]BF4
[Ru(η5-C5H5)(η6-1,3,5-C6H3Me3)]BF4
Ru(η5-C5H5)(η5-C5Me5)
5.30b
5.31b
4.18a
Ru(η5-C5H5)(η5-C5(CO2Me)5)
[Ru(η5-C5H5)(P(OMe)3)3]PF6
[Ru(η5-C5H5)(CO)3]PF6
4.93a
5.23a
6.30b
4.27b
4.57b
4.35b
Ru(η5-C5H5)(BHPz3)
Ru(η5-C5H5)(BH(3,5-Me2Pz)3)
Ru(η5-C5H5)(BPz4)
a
b
In CDCl3. In (CD3)2CO; Pz ) 2-pyrazolyl.
of the arene ligand, it is improbable that the steric bulk
of the incoming base can account for the lack of
reactivity. This is more likely to arise from the strongly
electron-donating nature of Me3tacn, which would lower
the electrophilicity of the arene ring relative to [RuL′-
(η6-C6H6)]2+ so that 1 reacts with the highly nucleophilic
hydride anion only. Reaction of the solution X with 1,3-
cyclohexadiene and cycloheptatriene in the presence of
zinc afforded 4 and [Ru(Me3tacn)((1-5-η)-C7H9)]PF6 (5),
respectively. In this method, 4 is presumably formed
via 1 and then reduced by hydride anions generated
from the combination of zinc and refluxing ethanol. For
complex 5, the role of the zinc/ethanol mixture is to
reduce the metal center (RuIII f RuII) as well as to
generate hydride anions in situ, which subsequently
attack the cycloheptatriene ring.
Sp ectr oscop y a n d Molecu la r Str u ctu r es. The 1H
chemical shifts of the cyclopentadienyl ring in a series
of related mixed-sandwich type ruthenium complexes
are listed in Table 2. The Cp protons in 2 appear as a
singlet at δ 3.77 (CDCl3)/δ 3.92 ((CD3)2CO), which is
significantly upfield from the other examples. This can
be attributed to the enhancement of π-basicity at the
ruthenium center by the σ-donating strength of Me3-
1
tacn. The H NMR spectra for 4 and 5 each reveal a
characteristic triplet at ca. δ 5.5 for the H3 proton in
η5-dienyl complexes.19 For complex 4, the doublet of
triplets centered at δ 2.35 for H6endo shows a large
geminal (2J ) coupling of 13.1 Hz to H6exo (at δ 1.45) and
smaller vicinal (3J ) coupling of 6.0 Hz to H1 and H5. No
vicinal coupling is observed between H6exo and H1 or H5
because the respective dihedral angles are approxi-
mately 90°.
Complexes 3-5 have been studied by X-ray crystal-
lography. Perspective views of the cations and selected
bond lengths and angles are presented in Figure 2 and
Tables 3-5, respectively. All three complexes display
a mixed-sandwich-type structure, and the η5-arene and
-cyclodienyl moieties are virtually planar (deviation
from mean planes within 0.1 Å). In 3, the C-C
distances of the C5 ring range from 1.409(12) to
1.447(11) Å and the Ru-C distances vary slightly
between 2.147(7) and 2.264(4) Å. Distortion of the C5
moiety is therefore small and is probably due to the
F igu r e 2. Perspective views of the cation in (top) [Ru-
(Me3tacn)(η5-C9H7)]PF6 (3), (middle) [Ru(Me3tacn)((1-5-η)-
C6H7)]PF6 (4), and (bottom) [Ru(Me3tacn)((1-5-η)-C7H9)]-
PF6 (5).
(18) Shirin, Z.; Pramanik, A.; Ghosh, P.; Mukherjee, R. Inorg. Chem.
1996, 35, 3431.
(19) Pertici, P.; Vitulli, G.; Paci, M.; Porri, L. J . Chem. Soc., Dalton
Trans. 1980, 1961.
influence of the adjacent ring. The average Ru-C
distance of 3 is 2.195 Å, which is similar to those in

Ru π-Arene and π-Cyclodienyl Complexes
Organometallics, Vol. 17, No. 2, 1998 155
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
Ta ble 5. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for [Ru (Me3ta cn )((1-5-η)-C7H9)]P F 6 (5)
(d eg) for [Ru (Me3ta cn )(η5-C9H7)]P F 6 (3)
Ru-N1
2.177(5)
2.159(5)
2.167(6)
2.152(6)
1.447(11)
1.413(11)
1.409(12)
1.431(11)
1.406(13)
Ru-N2
2.177(5)
2.264(6)
2.147(7)
2.244(6)
1.440(9)
1.419(12)
1.446(10)
1.340(12)
1.330(13)
Ru-N1
2.185(5)
2.218(5)
2.099(7)
2.143(8)
1.525(13)
1.41(3)
Ru-N2
2.247(6)
2.164(10)
2.141(6)
2.186(6)
1.456(12)
1.41(3)
Ru-N3
Ru-C10
Ru-C12
Ru-C4
Ru-N3
Ru-C10
Ru-C12
Ru-C14
C10-C11
C12-C13
C14-C15
Ru-C11
Ru-C13
C10-C11
C10-C18
C12-C13
C14-C15
C16-C17
Ru-C11
Ru-C13
C10-C16
C11-C12
C13-C14
C15-C16
C10-C14
C11-C12
C13-C14
C15-C16
C17-C18
1.361(13)
1.525(13)
1.497(10)
C11-C10-C16
C11-C12-C13
C13-C14-C15
C10-C16-C15
115.1(7)
122.4(6)
134.7(7)
120.6(7)
C10-C11-C12
C12-C13-C14
C14-C15-C16
127.0(9)
121.2(9)
106.3(6)
C11-C10-C14
C14-C10-C18
C11-C12-C13
C10-C14-C13
C13-C14-C15
C15-C16-C17
C10-C18-C17
107.9(6)
119.0(7)
109.4(7)
107.1(6)
134.4(7)
121.7(8)
120.1(7)
C11-C10-C18
C10-C11-C12
C12-C13-C14
C10-C14-C15
C14-C15-C16
C16-C17-C18
133.1(7)
107.3(6)
108.1(6)
118.5(6)
119.2(7)
121.5(7)
ridylmethyl)methylamine)18 show that the structure of
the η5-cyclodienyl ligand in 4 is unremarkable. The
average Ru-C distances at the η5-bonded moieties in 4
and 5 (2.161 and 2.147 Å, respectively) are similar to
that in [Ru(Me3tacn)((1-5-η)-C8H11)]+ (2.159 Å).9 How-
ever, it is apparent that the ruthenium-nitrogen con-
tact trans to the central carbon of the η5 fragment (Ru-
N1 in 4 and 5) is shorter than the remaining two. This
is presumably a consequence of the alleviation of steric
repulsion between Me3tacn and the respective cyclodi-
enyl ligand.
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for [Ru (Me3ta cn )((1-5-η)-C6H7)]P F 6 (4)
Ru-N1
Ru-N2
Ru-C6
Ru-C7
Ru-C8
2.194(6)
2.205(5)
2.153(9)
2.140(6)
2.187(6)
C1-C2
C3-C3a
C6-C7
C7-C8
C8-C9
1.327(12)
1.344(19)
1.402(9)
1.400(10)
1.501(9)
C7-C6-C7a
C7-C8-C9
118.1(8)
118.6(7)
C6-C7-C8
C8-C9-C8a
119.6(7)
102.5(6)
Ack n ow led gm en t. We thank The University of
Hong Kong and the Hong Kong Research Grants
Council for financial support, and the former is acknowl-
edged for a University Postdoctoral Fellowship (to M.C.-
W.C). S.-M.Y. is grateful for a Croucher Scholarship
administrated by the Croucher Foundation of Hong
Kong.
Ru(η5-C9H7)2 and Cp*Ru(η5-C9H7)21 (2.189 and 2.202
Å, respectively). Comparison of complex 4 with the
related complexes [Ru((1-5-η)-C6H6CN)(HBPz3)]22 and
[Ru((1-5-η)-C6H6CN)L′]+ (L′ ) (2-pyridylethyl)(2-py-
20
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Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data and refinement details, final positional parameters,
calculated coordinates (for hydrogen), anisotropic displacement
parameters, and bond lengths and angles for 3-5 (19 pages).
Ordering information is given on any current masthead page.
OM970617Y
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1975, 1710.
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5, 303.