Preparations and structures of (η6-arene)ruthenium(II) complexes bearing 1,1′-bis(diphenylphosphinomethyl)ferrocene or 1,1′-bis(diphenylphosphino)ferrocene

Article abstract of DOI:10.1016/S0022-328X(98)00499-9

Reactions of bis[dichloro(η⁶-arene)ruthenium] 1 with 1,1′-bis[(diphenylphosphino)methyl]ferrocene (dpmf) gave the dpmf-P,P′ bridged complexes [(η⁶-arene)RuCl₂]₂(μ-dpmf) 2, where arenes=(a) 1,2,3,4-Me₄C₆H₂; (b) C₆Me₆; (c) p-cymene; (d) 1,2,3,5-Me₄C₆H₂; (e) 1,3,5-Me₃C₆H₃; (f) 1,2,3-Me₃C₆H₃. Treatment of 2 with xylyl isocyanide (XylNC) in the presence of NaPF₆ produced the F-coordinated complex [(η⁶-arene)RuCl]₂(μ-dpmf)(PF₆)₂ 3a without containing XylNC. Reactions of 1 with 1,1′-bis(diphenylphosphino)ferrocene (dppf) formed the bridged complexes [(arene)RuCl₂]₂(μ-dppf)] 4, as well as the dpmf complexes. The similar reactions in the presence of NaPF₆ gave the chelated complexes [(η⁶-arene)RuCl(dppf-P,P′)](PF₆) 5. Crystal structures of 2a, 2d·2CH₂Cl₂, 4a·CH₂Cl₂ and 5b were confirmed by X-ray analyses and they have three-legged piano-stool structures. Crystal data are as follows: 2a triclinic, space group P1, with a=12.802(6), b=19.111(6), c=11.438(4) A, α=98.93(3), β=108.57(3), γ=90.42(3)°, V=2615(1) A³, Z=2 [R=0.051, R_w=0.052 for 4114 independent reflections with I>3.0σ(I)]; 2d·2CH₂Cl₂ monoclinic, space group C2/c, a=38.379(6), b=9.903(3), c=17.381(4) A, β=113.91(1)°, V=6038 A³ and Z=4 [R=0.057, R_w=0.054 for 1882 independent reflections with I>3.0σ(I)]; 4a·CH₂Cl₂ triclinic P1, with a=15.044(7), b=17.664(3), c=10.586(2) A, α=99.64(2), β=95.85(2), γ=94.74(2)°, V=2744(1) A³, Z=2 [R=0.065, R_w=0.072 for 4301 independent reflections I>3.0σ(I)]; 5b monoclinic, space group P2₁/n, a=15.036(4), b=17.192(5), c=15.983(3) A, β=92.92(2)°, V=4126(1) A³, Z=4 [R=0.070, R_w=0.079 for 3389 independent reflections I>3σ(I)]. Conformation of the ferrocenyl skeletons were determined by dihedral angles containing two Cp rings. In cyclic voltammertry (CV) of these complexes the Fe(II)/Fe(III) redox couples were quasi-reversible, but the Ru moieties were irreversible.

Full text of DOI:10.1016/S0022-328X(98)00499-9

Journal of Organometallic Chemistry 560 (1998) 223–232
Preparations and structures of (p6-arene)ruthenium(II) complexes
bearing 1,1%-bis(diphenylphosphinomethyl)ferrocene or
1,1%-bis(diphenylphosphino)ferrocene
Jian-Fang Mai 1, Yasuhiro Yamamoto *
Department of Chemistry, Faculty of Science, Toho Uni6ersity, Miyama, Funabashi, 274, Japan
Received 16 December 1997; received in revised form 3 February 1998
Abstract
Reactions of bis[dichloro(p6-arene)ruthenium] 1 with 1,1%-bis[(diphenylphosphino)methyl]ferrocene (dpmf) gave the dpmf-P,P%
bridged complexes [(p6-arene)RuCl2]2(v-dpmf) 2, where arenes=(a) 1,2,3,4-Me4C6H2; (b) C6Me6; (c) p-cymene; (d) 1,2,3,5-
Me4C6H2; (e) 1,3,5-Me3C6H3; (f) 1,2,3-Me3C6H3. Treatment of 2 with xylyl isocyanide (XylNC) in the presence of NaPF6
produced the F-coordinated complex [(p6-arene)RuCl]2(v-dpmf)(PF6)2 3a without containing XylNC. Reactions of 1 with
1,1%-bis(diphenylphosphino)ferrocene (dppf) formed the bridged complexes [(arene)RuCl2]2(v-dppf)] 4, as well as the dpmf
complexes. The similar reactions in the presence of NaPF6 gave the chelated complexes [(p6-arene)RuCl(dppf-P,P%)](PF6) 5.
Crystal structures of 2a, 2d·2CH2Cl2, 4a·CH2Cl2 and 5b were confirmed by X-ray analyses and they have three-legged piano-stool
˚
structures. Crystal data are as follows: 2a triclinic, space group P1, with a=12.802(6), b=19.111(6), c=11.438(4) A,
3
˚
h=98.93(3), i=108.57(3), k=90.42(3)°, V=2615(1) A , Z=2 [R=0.051, Rw=0.052 for 4114 independent reflections with
3
˚
˚
I\3.0|(I)]; 2d·2CH2Cl2 monoclinic, space group C2/c, a=38.379(6), b=9.903(3), c=17.381(4) A, i=113.91(1)°, V=6038 A
and Z=4 [R=0.057, Rw=0.054 for 1882 independent reflections with I\3.0|(I)]; 4a·CH2Cl2 triclinic P1, with a=15.044(7),
3
˚
˚
b=17.664(3), c=10.586(2) A, h=99.64(2), i=95.85(2), k=94.74(2)°, V=2744(1) A , Z=2 [R=0.065, Rw=0.072 for 4301
˚
independent reflections I\3.0|(I)]; 5b monoclinic, space group P21/n, a=15.036(4), b=17.192(5), c=15.983(3) A, i=
92.92(2)°, V=4126(1) A , Z=4 [R=0.070, Rw=0.079 for 3389 independent reflections I\3|(I)]. Conformation of the
3
˚
ferrocenyl skeletons were determined by dihedral angles containing two Cp rings. In cyclic voltammertry (CV) of these complexes
the Fe(II)/Fe(III) redox couples were quasi-reversible, but the Ru moieties were irreversible. © 1998 Elsevier Science S.A. All
rights reserved.
Keywords: (p6-Arene)ruthenium; Dppf–Ru complexes; Dpmf–Ru complexes; Electrochemistry
1. Introduction
introduction of a methylene group between the cy-
clopentadienyl (Cp) ring and phosphorus atom could
be more flexible than dppf, it is considered to have the
possibility of various conformers between two Cp rings,
as well as dppf. Our interest started from comparison
of coordination modes between dpmf and dppf. We
have reported that new dpmf was prepared from the
reaction of 1,1%-bis(dichloromethyl)ferrocene with
lithium diphenylphosphide and its molecule has a cen-
trosymmetrical structure at an iron atom as well as that
of dppf [2]. The reaction of dpmf with [PdCl2(MeCN)2]
1,1%-Bis(diphenylphosphino)ferrocene (dppf) is a well-
known metalloligand and its chemistry has been well
provided because of the conformational properties and
the ligand of metal complex catalysts [1]. Since 1,1%-bis[-
(diphenylphosphino)methyl]ferrocene (dpmf) formed by
* Corresponding author. Fax: + 81 474 751855.
1 On leave from Changchun Institute of Applied Chemistry, Chi-
nese Academy of Sciences.
or NiCl2 ·2H2O gave
a stable dimeric complex
0022-328X/98/$19.00 © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00499-9

224
J.-F. Mai, Y. Yamamoto / Journal of Organometallic Chemistry 560 (1998) 223–232
Table 1
Crystal data of (p6-1,2,3,4-Me4C6H2)2Ru2C4(dpmf) 2a, (p6-1,2,3,5-Me4C6H2)2Ru2Cl4(dpmf)·2CH2Cl2 2d·2CH2Cl2, (p6-1,2,3,4-Me4C6H2)2Ru2Cl4-
(dppf)·CH2Cl2 4a, and [(p6-Me6C6)RuCl(dppf)](PF6) 5b
Compound
2a
2d·2CH2Cl2
4a·CH2Cl2
5b
Formula
Molecular weight
Color
C56H60Cl4P2FeRu2
1194.84
Orange
C58H64Cl8P2FeRu2
1364.70
Orange
C55H58Cl6P2FeRu2
1251.72
Orange
C46H46ClF6P3FeRu
998.15
Orange
Crystal dimensions (mm)
0.20×0.20×0.20
16
0.30×0.40×0.1
2
0.50×0.2×0.10
8
0.40×0.35×0.12
4
Scan rate, (° min−1
)
Crystal system
Space group
Triclinic
P1 (no. 2)
Monoclinic
C2/c (no. 15)
Triclinic
P1 (no. 2)
Monoclinic
P21/n (no. 14)
Lattice parameters
a
b
c
12.802(6)
19.111(6)
11.438(4)
98.93(3)
108.57(3)
90.42(3)
2615(1)
2
38.379(6)
9.903(3)
17.381(4)
90.0
113.91(1)
90.0
6038(2)
4
1.501
15.044(7)
17.664(3)
10.586(2)
99.64(2)
95.85(2)
94.74(2)
2744(1)
2
15.036(4)
17.192(5)
15.983(3)
90.0
92.92(2)
90.0
4126(1)
4
1.607
h
i
k
3
˚
V (A )
Z
Dcalc. (g cm−3
)
1.517
11.45
1216
1.515
11.89
1268
v (cm−1
F(000)
)
11.73
2768
9.60
2032
No. reflections
9219
5658
9660
7524
No. of data [I\3.0|(I)]
No. of variables
R, Raw
4114
586
0.051, 0.052
1.39
1882
307
0.057, 0.054
1.48
4301
590
0.06, 0.072
1.98
3389
523
0.070, 0.079
2.30
GOFb
a R=SꢀFoꢁ−ꢁFcꢀ/SꢁFoꢁ and Rw=[S(ꢁFoꢁ−ꢁFcꢁ)2/SwꢁFoꢁ ] [w=1/|2(Fo)]
2 0.5
b GOF=[Sw(ꢁFoꢁ−ꢁFcꢁ)2/S(No−Nv)]0.5, where No=number of data and Nv=number of variables.
[M2Cl4(dpmf)2] (M=Ni or Pd) which has a macro-
cyclic structure [2].
FT/IR-5300. NMR spectroscopy was carried out on a
Bruker AC250. H-NMR spectra were measured at 250
1
Arene ruthenium complexes played an important role
as the precursors of catalysts in various organic synthe-
ses [3]. Their research is one of very attractive subjects
in the coordination chemistry. We reported previously
that the reaction of [(p6-arene)RuCl2]2 with bulky and
high basic aromatic phosphines bearing methoxy
groups at 2- and 6-positions gave the complexes con-
taining various coordination modes such as mono-
MHz using tetramethylsilane as an internal reference
and 31P{1H}-NMR spectra were measured at 101 MHz
using 85% H3PO4 as an external reference. Electro-
chemical measurements were carried out in a 0.05 M
solution of [n-Bu4N][ClO4]/MeCN–CH2Cl2 (1:1 ratio)
under an atmosphere of nitrogen after the solution was
deaerated by bubbling with nitrogen by use of a FUSO
HECS3 17S Potentiostat Coulometer Timer and a
FUSO HECS326 Digital Universal Signal Processing
Unit. The measurements were a conventional three-
electrode system: a Pt chip as a working electrode, a Pt
wire as a counter electrode and an AgꢁAgNO3 (0.1
M)–[n-Bu4N][ClO4]/MeCN (0.1 M) reference electrode.
All potentials are relative to a ferrocene/ferrocennium
couple (1×10−3 M), whose potential was 145 mV
versus a reference electrode.
hapto-(P-),
dihapto-
(P,O-;
P,OMe-),
and
trihapto-(P,OMe,OMe; P,O,OMe; P,O,O) [4]. We have
interest in the reactions of bis[dichloro(p6-
arene)ruthenium(II)] with new flexible dpmf, particu-
larly in confomations of ferrocenyl skeleton in metal
complexes. For comparison, the reactions with dppf
was also examined. A part of results has already been
reported elsewhere [5].
2.1. Reactions of [(p6-arene)RuCl2]2 1 with dppf and
2. Experimental
dpmf
All reactions were carried out under nitrogen atmo-
sphere. Bis[dichloro(p6-arene)ruthenium(II)] [6], dpmf
[2] and dppf [7] were prepared according to the litera-
ture. Dichloromethane, diethyl ether, and acetone were
distilled over CaH2. The IR spectra were measured on
2.1.1. Reaction of [(p6-1,2,3,4-Me4C6H2)RuCl2]2 1a
with dpmf
To a solution of 1a (31 mg, 0.05 mmol) in CH2Cl2
(15 ml) was added dpmf (29 mg, 0.05 mmol) at room
temperature (r.t.). After the mixture was stirred for 2 h,

J.-F. Mai, Y. Yamamoto / Journal of Organometallic Chemistry 560 (1998) 223–232
225
Fig. 1. Crystal structure of [(p6-1,2,3,4-Me4C6H2)2Ru2C4(dpmf)] 2a. Hydrogen atoms are omitted for clarity.
1
the solvent was removed to ca. 3 ml under reduced
pressure and ether was added to the solution to give
orange crystals of [(p6-1,2,3,4-Me4H2C6)RuCl2]2(v-
dpmf-P,P%) 2a·CH2Cl2 (46 mg, 72%). 1H-NMR
(CDCl3): l 1.58 (s, C6Me2), 2.04 (d, JPH=2.0 Hz,
C6Me2), 3.19 (s, CH2), 3.46–3.56 (m, C5H4), 4.16 (d,
2f (43%). H-NMR (CDCl3): l 1.86 (s, C6Me2), 2.06
(s, C6Me), 3.29 (s, CH2), 3.51–3.62 (m, C5H4), 4.29 (d,
J
HH=6.0 Hz, C6H2), 4.62 (m, C6H), 7.2–7.6 (m, Ph)
ppm. 31P{1H}-NMR (CDCl3): l 32.54 (s) ppm. Anal.
Calc. for C54H56Cl4P2FeRu2: C 55.59, H 4.84. Found: C
54.70, H 4.53%.
J
PH=3.2 Hz, C6Me4H2), 5.30 (s, CH2Cl2), 7.2–7.7 (m,
Ph) ppm. 31P{1H}-NMR (CDCl3): l 32.41 (s) ppm.
Anal. Calc. for C57H62Cl6P2FeRu2: C 53.50, H 4.88.
Found: C 53.86, H 4.79%.
2.1.2. Reaction of 2a with xylyl isocyanide in the
presence of NaPF6
To a mixture of 2a (40 mg, 0.034 mmol) and xylyl
isocyanide (17.6 mg, 0.13 mmol) in CH2Cl2 (5 ml) and
acetone (5 ml) was added NaPF6 (84 mg, 0.5 mmol) at
r.t. After stirring for 4 h, the solvents were removed
under reduced pressure and the residue was extracted
with CH2Cl2 (2×10 ml). The solvent was concentrated
to ca. 3 ml and ether was added to give orange crystals
of 3a (19 mg, 40%). 1H-NMR (CD2Cl2): l 1.54 (s,
C6Me2), 2.09 (d, JPH=2.3 Hz, C6Me), 3.14 (b, C5H2
and C6H2), 3.58 (bs, C5H2), 4.20 (d, JPH=3.4 Hz,
C6H2), 7.3–7.6 (m, Ph) ppm. 31P{1H}-NMR (CD2Cl2):
l 35.80 (s), −142.33 (sep, JPH=710 Hz) ppm. Anal.
Calc. for C56H60Cl2P4F12FeRu2: C 47.57, H 4.28.
Found: C 48.47, H 4.17.
1
2b (67%). H-NMR (CDCl3): l 1.64 (s, C6Me6), 3.07
(s, CH2), 3.42–3.51 (m, C5H4), 7.2–7.7 (m, Ph) ppm.
31P{1H}-NMR (CDCl3): l 30.60 (s) ppm. Anal. Calc.
for C60H68Cl4P2FeRu2: C 57.61, H 5.48. Found: C
57.10, H 5.33%.
1
2c·0.5CH2Cl2 (59%). H-NMR (CDCl3): l 0.82 (d,
JHH=6.7 Hz, CHMe2), 1.78 (s, Me), 2.49 (sep, JHH=
6.7 Hz, CMe2H), 3.12 (s, CH2), 3.42–3.55 (m, C5H4),
5.12 (q, a center value of a A2B2 type, JHH=5.7 Hz,
C6H4), 5.30 (s, CH2Cl2), 7.3–7.7 (m, Ph) ppm.
31P{1H}-NMR (CDCl3): l 28.14 (s) ppm. Anal. Calc.
for C56.5H61Cl5P2FeRu2: C 54.85, H 4.97. Found: C
54.83, H 4.69%.
1
2d·1.5CH2Cl2 (60%). H-NMR (CDCl3): l 1.47 (s,
C6Me), 1.79 (s, C6Me2), 1.90 (s, C6Me), 3.14 (s, CH2),
3.44–3.55 (m, C5H4), 4.37 (s, C6H2), 5.30 (s, CH2Cl2),
7.2–7.7 (m, Ph) ppm. 31P{1H}-NMR (CDCl3): l 30.79
(s) ppm. Anal. Calc. for C57.5H63Cl7P2FeRu2: C 52.23,
H 4.80. Found: C 52.20, H 4.66%.
2.1.3. Reaction of [(p6-1,2,3,4-Me4C6H2)RuCl2]2 1a
with dppf
To a solution of 1a (31 mg, 0.05 mmol) in CH2Cl2
(15 ml) was added dppf (28 mg, 0.05 mmol) at r.t. After
the mixture was stirred for 2 h, the solvent was re-
moved to ca. 3 ml under reduced pressure and ether
was added to the solution to give orange crystals of
[(p6-1,2,3,4-Me4C6H2)RuCl2]2(v-dppf-P,P%)]
1
2e·0.5CH2Cl2 (62%). H-NMR (CDCl3): l 1.81 (d,
JPH=2.8 Hz, C6Me), 3.14 (s, CH2), 3.44–3.58 (m,
C5H4), 4.61 (s, C6H3), 5.30 (s, CH2Cl2), 7.2–7.7 (m, Ph)
ppm. 31P{1H}-NMR (CDCl3): l 29.84 (s) ppm. Anal.
Calc. for C54.5H57Cl5P2FeRu2: C 54.13, H 4.75. Found:
C 53.54, H 4.70%.
4a·0.5CH2Cl2 (75%). 1H-NMR (CDCl3): l 1.68 (s,
C6Me2), 2.05 (d, JPH=2.5 Hz, C6Me2), 3.9–4.1 (m,
C5H4 and C6H2), 7.2–7.7 (m, Ph) ppm. 31P{1H}-NMR

226
J.-F. Mai, Y. Yamamoto / Journal of Organometallic Chemistry 560 (1998) 223–232
Fig. 2. Crystal structure of (p6-1,2,3,5-Me4C6H2)2Ru2Cl4(dpmf)·2CH2Cl2 2d·2CH2Cl2. Hydrogen atoms, solvated molecules and PF6 are omitted
for clarity.
(CDCl3):
l
20.70 (s) ppm. Anal. Calc. for
mg, 0.10 mmol) in CH2Cl2 (15 ml) and acetone (10 ml)
was added NaPF6 (84 mg, 0.5 mmol) at r.t. After the
mixture was stirred for 2 h, the solvent was removed
under reduced pressure and the residue was extracted
with CH2Cl2. The solvent was concentrated to 3 ml,
and ether was added to the solution to give orange
crystals of [(p6-1,2,3,4-Me4H2C6)RuCl(dppf-P,P%)](PF6)
C54.5H57Cl5P2FeRu2: C 54.13, H 4.75. Found: C 54.33,
H 4.69%.
4b·0.5CH2Cl2 (65%). H-NMR (CDCl3): l 1.58 (s,
C6Me6), ca. 4.0 (b, C5H4), 5.30 (s, CH2Cl2), 7.2–7.6 (m,
Ph) ppm. 31P{1H}-NMR (CDCl3): l 20.16 (bs) ppm.
Anal. Calc. for C58.5H65Cl5P2FeRu2: C 55.53, H 5.18.
Found: C 55.77, H 5.14%.
1
1
5a (25 mg, 26%). IR (nujol): 833 cm−1 (PF6). H-NMR
1
4c·1.5CH2Cl2 (69%). H-NMR (CDCl3): l 0.96 (d,
(CDCl3): l 1.28 (bs, C6Me2), 1.92 (bs, C6Me2), 4.01,
4.19, 4.30, 5.04 (s, C5H), 4.84 (bs, C6H2), 7.3–7.7 (m,
Ph) ppm. 31P{1H}-NMR (CDCl3): 636.67 (s), −144.5
JHH=6.9 Hz, CHMe2), 1.72 (s, C6Me), 2.51 (sep,
JHH=6.9 Hz, CHMe2), 3.87 (s, C5H2), 4.16 (s, C5H2),
5.07 (m, C6H4), 5.30 (s, CH2Cl2), 7.3–7.8 (m, Ph) ppm.
31P{1H}-NMR (CDCl3): l 18.50 (s) ppm. Anal. Calc.
for C55.5H59Cl7P2FeRu2: C 51.51, H 4.59. Found: C
51.61, H 4.56%.
(sep,
JPF=710 Hz) ppm. Anal. Calc. for
C44H42ClF6P3FeRu: C 54.48, H 4.36. Found: C 54.13,
H 4.21%.
5b (76%). IR (nujol): 839 cm−1 (PF6). 1H-NMR
(CDCl3): l 1.53 (s, C6Me6), 3.98, 4.11, 4.25, 4.94 (s,
C5H), 7.47.9 (m, Ph) ppm. 31P{1H}-NMR (CDCl3): l
33.96 (s), −144.6 (sep, JPF=710 Hz) ppm. Anal. Calc.
for C46H46ClF6P3FeRu: C 55.35, H 4.62. Found: C
55.40, H 4.38%.
4d·2CH2Cl2 (46%). 1H-NMR (CDCl3): l 1.55 (s,
C6Me), 1.86 (s, C6Me2), 1.95 (s, C6Me), ca. 4.0 (b,
C6H2 and C5H2), 5.30 (s, CH2Cl2), 7.2–7.7 (m, Ph)
ppm. 31P{1H}-NMR (CDCl3): l 21.00 (s) ppm. Anal.
Calc. for C56H60Cl8P2FeRu2: C 50.32, H 4.52. Found: C
50.89, H 4.51%.
5c (56%). IR (nujol): 839 cm−1 (PF6). 1H-NMR
(CDCl3): l 0.85 (d, JHH=7.0 Hz, CHMe2), 0.94 (s,
C6Me), 2.65 (sep, JHH=7.0 Hz, CHMe2), 4.05, 4.25,
4.33, 5.04 (s, C5H), 5.10 (d, JHH=5.0 Hz), 5.68 (c,
C6H2), 7.4–7.7 (m, Ph) ppm. 31P{1H}-NMR (CDCl3): l
36.52 (s), −144.3 (sep, JPF=710 Hz) ppm. Anal. Calc.
for C44H42ClF6P3FeRu: C 54.48, H 4.36. Found: C
54.16, H 4.28%.
1
4e·0.5CH2Cl2 (63%). H-NMR (CDCl3): l 1.85 (s,
C6H3Me3), ca. 4.0 (m, C5H4), 4.37 (s, C6H3), 5.30 (s,
CH2Cl2), 7.3–7.7 (m, Ph) ppm. 31P{1H}-NMR
(CDCl3): l 20.24 (s) ppm. Anal. Calc. for C52.5H53Cl5
P2FeRu2: C 53.38, H 4.52. Found: C 52.95, H 4.42%.
4f·0.5CH2Cl2 (49%). 1H-NMR (CDCl3): l 1.87 (s,
C6Me2), 2.04 (s, C6Me), 3.90–4.04 (m, C5H4 and
C6H2), 5.30 (s, CH2Cl2), 4.65 (m, C6H), 7.2–7.6 (m,
Ph) ppm. 31P{1H}-NMR (CDCl3): l 20.54 (s) ppm.
Anal. Calc. for C52.5H53Cl5P2FeRu2: C 53.38, H 4.52.
Found: C 53.90, H 4.51%.
5d (52%). IR (nujol): 833 cm−1 (PF6). 1H-NMR
(CDCl3): l 1.36 (bs, C6Me), 1.59 (bs, C6Me2), 3.89,
3.95, 4.32, 5.17 (s, C5H), 4.98 (bs, C6H2), 7.47.7 (m, Ph)
ppm. 31P{1H}-NMR (CDCl3): l 34.61 (s), −144.4 (sep,
2.1.4. Reaction of [(p6-1,2,3,4-Me4C6H2)RuCl2]2 1a
with dppf in the presence of NaPF6
To a mixture of 1a (31 mg, 0.05 mmol) and dppf (55
JPF=710
Hz)
ppm.
Anal.
Calc.
for
C44H42ClF6P3FeRu: C 54.48, H 4.36. Found: C 53.76,
H 4.09%.

J.-F. Mai, Y. Yamamoto / Journal of Organometallic Chemistry 560 (1998) 223–232
227
Fig. 3. Crystal structure of (p6-1,2,3,4-Me4C6H2)2Ru2Cl4(dppf)·CH2Cl2 4a. Hydrogen atoms and CH2Cl2 are omitted for clarity.
5e (67%). IR (nujol): 837 cm−1 (PF6). 1H-NMR
(CDCl3): l 1.73 (s, C6H3Me3), 3.98, 4.08, 4.30, 5.08
(s, C5H), 4.83 (s, C6H3), 7.47.9 (m, Ph) ppm.
31P{1H}-NMR (CDCl3): l 35.17 (s), −144.3 (sep,
2.2. X-ray analysis
2.2.1. Data collection
Complexes (2a, 2d·2CH2Cl2, 4a·CH2Cl2 and 5b)
were recrystallized from CH2Cl2/ether. Cell constants
were determined from 15–20 reflections on Rigaku
four-circle automated diffractometer AFC5S. The
crystal parameters along with data collections are
summarized in Table 1. Data collection was carried
out by a Rigaku AFC5S diffractometer. Intensities
were measured by the 2q−ꢀ scan method using
JPF=710 Hz) ppm. Anal. Calc. for C43H40
ClF6P3FeRu: C 54.02, H 4.22. Found: C 54.07, H
4.27%.
5f (31%). IR (nujol): 839 cm−1 (PF6). 1H-NMR
(CDCl3): l 1.57 (bs, C6Me2), 1.88 (bs, C6Me), 4.05,
4.26, 4.35, 5.18 (s, C5H), 4.66 (bs, C6H2), 5.45 (bs,
C6H), 7.47.8 (m, Ph) ppm. 31P{1H}-NMR (CDCl3): l
36.53 (s), −144.3 (sep, JPF=710 Hz) ppm. Anal.
Calc. for C43H40ClF6P3FeRu: C 54.02, H 4.22. Found:
C 53.38, H 3.95%.
˚
Mo–Kh radiation (u=0.71069 A). Throughout the
data collection the intensities of the three standard
reflections were measured every 200 reflections as a
check of the stability of the crystals and any decay
was not observed. Intensities were corrected for
Lorentz and polarization effects. The absorption cor-
rection was made. Atomic scattering factors were
taken from the usual tabulation [8]. Anomalous dis-
persion effects were included in Fcalc [9]; the values of
Df% and Df%% were from Creagh and McAuley [10]. All
calculations were performed using the teXsan crystal-
lographic software package of Molecular Structure
Corporation.
2.1.5. Reaction of [(p6-C6Me6)RuCl{P(2-o-6-
MeOC6H3Ph2}] with dpmf in the presence of NaPF6
To
a
mixture of [(p6-C6Me6)RuCl{P(2-o-6-
MeOC6H3)Ph2}] (59 mg, 0.10 mmol) and dpmf (29
mg, 0.05 mmol) in CH2Cl2 (15 ml) and acetone (10
ml) was added Na4PF6 (33 mg, 0.20 mmol) at r.t.
After the mixture was stirred for 2 h, the solvent was
removed under reduced pressure and the residue was
extracted with CH2Cl2. The solvent was concentrated
to 3 ml, and ether was added to the solution to give
orange crystals of [(p6-C6Me6)Ru{P(2-o-6-MeOC6
H3Ph2}]2(dpmf) 6 (25 mg, 25.3%). IR (nujol): 1578,
1551, 835 cm−1 (PF6). 31P{1H}-NMR (CD2Cl2): A; l
31.45 (d, JPP=50.1 Hz, dpmf), 50.84 (d, JPP=50.1 Hz,
MDMPP-O,P); B; 31.14 (d, JPP=50.1 Hz, dpmf),
50.90 (d, JPP=50.1 Hz, MDMPP-O,P); −142.4 (sep,
2.2.2. Determination of the structures
The structure of 2a was solved by direct methods
and 2d·2CH2Cl2, 4a·CH2Cl2 and 5b were solved by
Patterson methods (DIRDIF92 PATTY). The ruthe-
nium and iron atoms were located in the initial E
map, and subsequent Fourier syntheses gave the posi-
tions of other non-H atoms. The iron atom of
2d·2CH2Cl2 was occupied at the center of the sym-
metry. Hydrogen atoms were calculated at the ideal
J
PF=706.0 Hz) ppm. Anal. Calc. for C98H100
O4F12P6FeRu2: C 58.45, H 5.01. Found: C 58.41, H
5.03%.

228
J.-F. Mai, Y. Yamamoto / Journal of Organometallic Chemistry 560 (1998) 223–232
Fig. 4. Crystal structure of [(p6-Me6C6)RuCl(dppf)](PF6) 5b. Hydrogen atoms and PF6 are omitted for clarity.
In the 31P{1H}-NMR spectra the chemical shift of the
coordinated dpmf ligand appeared as a singlet at l ca.
30 ppm, shifting to the down field compared with that
of free dpmf, in which the chemical shift difference
(D=lcom−lfree) between free and coordinated dpmf’s is
ca. 42 ppm. There is no systematic relationship between
the number of the methyl groups and chemical shifts, but
in the complexes bearing the same number of methyl
groups (for example: 2a and 2d, and 2e and 2f), the
chemical shifts of the complexes containing the high
˚
positions with the C–H distance of 0.95 A, and were
not refined. The positions of the non-H atoms were
refined with anisotropic thermal parameters by using
full-matrix least-squares methods. Final difference
Fourier syntheses showed peaks at heights up to 0.88–
−3
˚
1.10 e A
.
3. Results and discussion
3.1. Reactions of [(p6-arene)2Ru2Cl4] 1 with dpmf
When arene ruthenium complexes [(p6-arene)2Ru2Cl4]
1 (arene=(a) 1,2,3,4-Me4C6H2; (b) C6Me6; (c) p-cymene;
(d) 1,2,3,5-Me4C6H2; (e) 1,3,5-Me3C6H3; (f) 1,2,3-
Me3C6H3) were treated with dpmf in CH2Cl2 at r.t. in a
1:1 ratio, orange or reddish orange crystals 2, formulated
as [(p6-arene)2Ru2Cl4(dpmf)], were isolated. The struc-
tures of these complexes were confirmed by X-ray
analyses of 2a and 2d. Molecules displayed a three-legged
piano-stool structure which the (arene)ruthenium moiety
was surrounded by a phosphorus and two chloride
atoms, and two arene ruthenium moieties were bridged
through the dpmf ligand (Figs. 1 and 2) (vide infra).
In the 1H-NMR spectrum in CDCl3 one of two kinds
of methyl protons of 2a and the methyl protons of 2e
appeared at l 2.04 and 1.81 ppm as a doublet by coupling
with the phosphorus nuclei, respectively, whereas in
other complexes they appeared as a singlet without
showing coupling. The h- and i-protons of the Cp rings
were observed as singlets in the range of l 3.1–3.6 ppm,
shifting to the higher field by ca. 0.4–0.7 ppm than those
of free dpmf.
Table 2
˚
Selected bond lengths (A), angles (°) and torsion angles (°) of 2a
˚
Bond lengths (A)
Ru(1)–Cl(1)
Ru(1)–P(1)
Ru(2)–Cl(4)
Ru–C(arene)
2.404(3) Ru(1)–Cl(2)
2.340(3) Ru(2)–Cl(3)
2.407(3) Ru(2)–P(2)
2.406(3)
2.407(3)
2.349(3)
2.04a
2.21a
Fe–C(Cp)
Bond angles (°)
Cl(1)–Ru(1)–Cl(2)
Cl(2)–Ru(1)–P(1)
Cl(3)–Ru(2)–P(2)
Ru(1)–P(1)–C(11)
Ru(1)–P(1)–C(23)
C(11)–P(1)–C(23)
Ru(2)–P(2)–C(34)
Ru(2)–P(2)–C(41)
C(34)–P(2)–C(41)
C(24)–Fe–C(29)
88.3(1) Cl(1)–Ru(1)–P(1)
88.1(1) Cl(3)–Ru(2)–Cl(4)
84.20(10) Cl(4)–Ru(2)–P(2)
105.2(5) Ru(1)–P(1)–C(17)
113.8(3) C(11)–P(1)–C(17)
105.4(4) C(17)–P(1)–C(23)
114.5(3) Ru(1)–P(2)–C(35)
116.1(3) C(34)–P(2)–C(35)
104.7(4) C(35)–P(2)–C(41)
158.3(4)
82.8(1)
88.3(1)
87.6(1)
113.3(3)
105.2(5)
105.4(4)
109.9(3)
106.8(5)
103.9(5)
Torsion angles (°)
Ru(1)–P(1)–C(23)–C(24) −151.0(6) Ru(2)–P(2)–C(34)–C(29) −166.1(7)
a Mean values between metal (Ru or Fe) and carbon atoms of the
arene or Cp ring.

J.-F. Mai, Y. Yamamoto / Journal of Organometallic Chemistry 560 (1998) 223–232
229
Table 3
Selected bond lengths (A) and angles (°) of 2d·2CH2Cl2
intensity ratio, in addition to at l 7.3–7.6 ppm due to
the aromatic protons, assigned as C6Me2, C6Me2, a sum
of CH2 and C5H2, C5H2, and aromatic protons of the
arene, respectively. The NMR pattern was in close
agreement with that of 2a. The 31P{1H}-NMR spectrum
showed a singlet at 35.80 ppm, similar to that of 2a. Since
complex 3a has a coordinatively unsaturated structure
with a 16-electron count, it is assumed at present that one
F atom of the PF6 anions participated with coordination
to metals to satisfy an 18-electron count. The detailed
structure is remained unknown. The F-coordination of
the PF6 anion has been noted in various complexes [12].
˚
˚
Bond lengths (A)
Ru(1)–Cl(1)
Ru(1)–P(1)
Ru–C(arene)
2.402(4) Ru(1)–Cl(2)
2.342(3)
2.403(3)
2.04a
2.21a
Fe–C(Cp)
Bond angles (°)
Cl(1)–Ru(1)–Cl(2)
Cl(2)–Ru(1)–P(1)
Ru(1)–P(1)–C(6)
Ru(1)–P(1)–C(13)
C(6)–P(1)–C(13)
C(5)–Fe–C(5)a
87.8(1)
84.4(1)
115.9(4)
105.7(5)
105.7(5)
180.0
Cl(1)–Ru(1)–P(1)
87.4(1)
Ru(1)–P(1)–C(7) 117.3(4)
C(6)–P(1)–C(7) 100.8(5)
C(7)–P(1)–C(13) 105.6(6)
Torsion angle (°)
Ru(1)–P1–C6–C5 −179.7(8)
3.2. Reactions of [(p6-arene)2Ru2Cl4] 1 with dppf
a Mean values between metal (Ru or Fe) and carbon atoms of the
arene or Cp ring.
It has been known that the reaction of 1c with dppf
gave the dppf bridged complex [(p-cymene)RuCl2]2(v-
dppf-P,P%), but the detailed structural analysis has not
yet been examined [13]. To compare reactivity between
dpmf and dppf and to obtain detailed structural informa-
tion, reactions of 1 with dppf were carried out. When 1
was treated with dppf in a 1:1 ratio in CH2Cl2 at r.t.,
orange crystals formulated as [(p6-arene)RuCl2]2(dppf) 4
and were obtained in 50–75% yields. The molecule was
confirmed to have a structure similar to that of 2 by an
X-ray analysis of [(p6-1,2,3,4-Me4C6H2)RuCl2]2(v-dppf-
P,P%) 4a (Fig. 3).
symmetrical arene rings appeared at the upper field. The
electron richness of arene ligand is not the only factor
which contributes to the chemical shift [11].
In some attempts to extract Cl anions the reactions of
2a with PhCꢀCH in alcoholic NaOH to prepare an
alkynyl complex or with CO in the presence of NaPF6
were undertaken, but no complexes identified were
obtained. When 2a was treated with xylyl isocyanide in
the presence of NaPF6 in a mixture of CH2Cl2 and
acetone, unstable orange solids 3a were isolated in 40%
yield. Surprisingly an isocyanide molecule could not be
confirmed from the IR spectrum, but it showed the
presence of the PF6 ligand at 841 cm−1. Complex 3a was
formulated as (1,2,3,4-Me4C6H2)2Ru2Cl2(dpmf)(PF6)2
1
In the H-NMR spectrum of 4a, one of two kinds of
methyl protons on the arene rings was observed as
doublets and another one as a singlet, which was also the
case in 2. In other complexes they appeared as singlets.
The h- and i-protons of the Cp rings could be
classified by two types of signals. In 4a, 4c, and 4f they
were observed as two singlets at l ca 4.0 ppm, whereas
in 4b, 4d, and 4e they were observed as one broad signal.
When the spectra of 4d and 4e were measured at 50°C,
one broad signal was separated as two broad singlets at
l 4.04 and 4.15 ppm for 4e, and at l 4.03 and 4.11 ppm
for 4d, respectively, assignable to either of the h- or
i-protons on the Cp rings, but that of 4b was kept still
broad, likely due to the more steric demand of hexam-
ethybenzene than 1,3,5-trimethylbenzene and 1,2,3,5-te-
tramethylbenzene.
The difference in the NMR behaviour is assumed to
be responsible for the methyl groups on the arene rings
but this does not necessarily depend on the number of
the substituent groups on the arene rings, as found
between 1,2,3,5- and 1,2,3,4-Me4C6H2 complexes and
between 1,3,5- and 1,2,3-Me3C6H3 complexes, but ap-
pears to depend on the partial crowding in the arene
rings. Similar behavior has been noted for reactivities of
(2,6-dimethoxyphenyl)diphenylphosphine toward bis[-
dichloro(p6-arene)ruthenium(II)] [4]. The 31P{1H}-NMR
spectrum appeared at l ca. 20 ppm, shifting to the down
field by 37 (D) ppm compared with the chemical shift of
free dppf and to the higher field by ca. 10 ppm than those
1
from an elemental analysis. The H-NMR spectrum in
CD2Cl2 showed five signals at l 1.54 (s), 2.09 (d), 3.14
(br), 3.58 (br), 4.20 (d) ppm consisting of a 12:12:8:4:4
Table 4
˚
Selected bond lengths (A), angles (°) and torsion angles (°) of
4a·CH2Cl2
˚
Bond lengths (A)
Ru(1)–Cl(1)
Ru(1)–P(1)
Ru(2)–Cl(4)
Ru–C(arene)
2.404(5) Ru(1)–Cl(2)
2.350(4) Ru(2)–Cl(3)
2.399(3) Ru(2)–P(2)
2.400(3)
2.414(3)
2.351(4)
2.04a
2.22a
Fe–C(Cp)
Bond angles (°)
Cl(1)–Ru(1)–Cl(2)
Cl(2)–Ru(1)–P(1)
Cl(3)–Ru(2)–P(2)
Ru(1)–P(1)–C(11) 108.8(4)
Ru(1)–P(1)–C(23) 113.9(4)
C(11)–P(1)–C(23) 105.4(5)
Ru(2)–P(2)–C(28) 114.8(4)
Ru(2)–P(2)–C(39) 121.6(4)
C(28)–P(2)–C(39) 104.7(5)
88.7(1)
87.8(1)
87.8(1)
Cl(1)–Ru(1)–P(1)
87.2(2)
C1(3)–Ru(2)–Cl(4) 89.3(1)
C1(4)–Ru(2)–P(2) 88.1(1)
Ru(1)–P(1)–C(17) 122.9(4)
C(11)–P(1)–C(17) 98.8(6)
C(17)–P(1)–C(23) 104.9(5)
Ru(1)–P(2)–C(33) 108.3(5)
C(28)–P(2)–C(33) 103.1(6)
C(33)–P(2)–C(39) 102.3(6)
C(23)–Fe–C(28)
148.0(5)
a Mean values between metal (Ru or Fe) and carbon atoms of the
arene or Cp ring.

230
J.-F. Mai, Y. Yamamoto / Journal of Organometallic Chemistry 560 (1998) 223–232
Table 5
Structural parameters of the ferrocenyl skeleton
~ (°)a
q (°)b
CA–Fe–CB (°)
P···P (A)
Conformation
˚
dpmf
2a
2d
4a
5b
180.0
141.0
180.0
118.6
3.9
0
1.4
0
4.4
4.5
180.0
158.3
180.0
148.0
105.4
9.61
9.35
9.62
6.43
3.41
Antiperiplanar
Anticlinal (eclipsed)
Antiperiplanar
Anticlinal (staggered)
Synperiplanar
a The torsion angle is defined as CA–XA–XB–CB, where CA is carbon atom in Cp ring A that is bonded to a P atom or CH2 group (likewise for
CB) and XA and XB are the centroids of the two Cp rings.
b q is the dihedral angles between the two Cp rings.
of the corresponding bridged dpmf complexes, arising
from higher nucleophilicity of dpmf compared with
dppf.
An attempt to replace Cl anions by CO in the
presence of NaPF6 was unsuccessful to obtain isolable
complexes.
Ph2P] in a 1:2 ratio in the presence of an excess of NaPF6
at r.t., orange crystals 6 formulated as [{(p6-C6Me6)Ru-
(MDMPP-P,O)}2(dpmf)](PF6)2 were obtained. The
31P{1H}-NMR spectrum showed four doublets with two
pairs of 31.45/50.84 (A) and 31.14/50.9 (B) ppm consist-
ing of JPP=50.1 Hz, and the intensity ratio between A
and B is 2:3. The signals at l ca. 31 ppm are assignable
to dpmf, and those at l ca. 50 ppm to other P nuclei.
This spectrum is a result of the diastereomers derived
from two chiral Ru centers.
3.3. Reactions of [(p6-arene)2Ru2Cl4] 1 with dppf in
the presence of NaPF6
When 1a was treated with dppf in a 1:2 molar ratio
in the presence of NaPF6 at r.t., orange crystals 5a
formulated as [(p6-1,2,3,4-Me4C6H2)RuCl(dppf)](PF6)
were obtained in 26% yield. Complexes bearing the arene
rings such as C6Me6 (5b), p-cymene (5c), 1,2,3,5-
Me4C6H2 (5d), 1,3,5-Me3C6H3 (5e), and 1,2,3-Me3C6H3
(5f) could be readily prepared from the reactions of dppf
with the corresponding arene ruthenium complexes in the
presence of NaPF6. The presence of the PF6 group in 5
was confirmed by an appearance of a strong band at ca.
3.4. Molecular structures
3.4.1. Complexes 2a, 2d ·2CH2Cl2, and 4a ·CH2Cl2
Complexes 2d and 4a were crystallized to contain
CH2Cl2 as a solvated molecule. The molecules of 2a,
2d·CH2Cl2 and 4a·CH2Cl2 consist of the dinuclear
structures bridged by dpmf or dppf ligand. Complex
2d·CH2Cl2 has a centrosymmetric structure with an
inversion center at a Fe atom. The ruthenium atoms are
surrounded by arene, P and two Cl atoms and the
molecules have the three-legged piano-stool conforma-
tion. The selected bond lengths and angles are listed in
Tables 2–4.
840 cm−1
.
The methyl and aromatic protons on the arene rings
of 5b, 5c and 5e appeared as sharp singlets without
showing the coupling with coordinated phosphorus
atoms. However those of 5a, 5d and 5f bearing partially-
crowded arene rings displayed broad singlets.
The characteristic feature is the presence of four kinds
of protons in the range from l 4.0 to 5.0 ppm responsible
for the protons of Cp rings. For example, 5b showed four
singlets at 3.98, 4.11, 4.30, 5.05 and 5.04 ppm. This inequ-
ivalence is responsible for the rigid ferrocene moiety by
the chelation of the dppf ligand, as depicted in Fig. 4.
The 31P{1H}-NMR spectra appeared at l ca. 35 ppm,
being a downfield shift of ca. 15 ppm compared with those
of the corresponding bridged dppf complexes, likely due
to a salt-like complexes.
The Ru–Cl and Ru–P lengths of 2a, 2d and 4a are ca.
˚
2.40 and 2.34 A, and the average values of the Ru–C and
Fe–C lengths concerning the Ru–arene and Fe–Cp
bonds are 2.20 and 2.04 A, respectively. Their values do
not depend on arene and phosphorus ligands.
˚
In the dpmf complexes (2a and 2d), the Cl–Ru–Cl
angle and one of the P–Ru–Cl bond angles are ca. 88°
and another P–Ru–Cl one is ca. 84°, whereas the
Cl–Ru–Cl and P–Ru–Cl angles of the dppf complex 4a
are similar values with ca. 88°, likely minimizing steric
repulsion due to higher rigidity of dppf than dpmf.
The structural parameters of the ferrocenyl skeleton
are listed in Table 5. The dihedral angles between two
Cp rings are 1.4° for 2a, 0° for 2d and 4.4° for 4a, being
not significantly different from those found in other dppf
complexes.
Similar reactions with dpmf were carried out to isolate
the chelated dpmf complexes, but such complexes could
not be obtained. An introduction of the CH2 group
between the Cp ring and P atom appear to prevent the
chelation conformation, because of its high freedom and
long P–P distance.
The conformation of dppf in the dppf complexes has
been classified by six categories which were defined by
torsion angles (~) CA–XA–XB–CB, where CA is a carbon
atom in Cp ring A that is bonded to a P atom
When dpmf was treated with (p6-C6Me6)RuCl-
(MDPMPP-P,O) [MDMPP-P,O=2-o-6-MeOC6H3)-

J.-F. Mai, Y. Yamamoto / Journal of Organometallic Chemistry 560 (1998) 223–232
231
Fig. 5. Conformations of the ferrocenyl rings.
(likewise for CB) and XA and XB are the centroids of the
two Cp rings [1]. The classification could be also applied
in dpmf complexes. The torsion angles of 2a, 2d and 4a
are 141.0, 180.0 and 118.6°, respectively. Their results
suggested that conformations of the two Cp rings were
anticlinal (eclipsed) for 2a, antiperiplanar for 2d, and
anticlinal (staggered) for 4a, respectively, as depicted in
Fig. 5. Anticlinal (eclipsed) conformation has been
observed in a three-legged piano-stool complex (p5-
MeCp)Mn(CO)2(dppf-P) [14] and in octahedral com-
plexes [Mn2(CO)9]2(v-dppf) [15], cis-[Mo(CO)5(dppf-P)]
[16], and [Re2(CO)9]2(v-dppf) [15]. Antiperiplanar ones
have been noted in [M(CO)5]2(v-dppf) (M=Cr, Mo)
[17] and cis-[Mn2Cl2(CO)8(v-dppf)] [18] in addition to
free dppf [19] and dmpf [3]. There are known a few
complexes having an anticlinal staggered conformation,
and one of them is Ag2(v-C6H5CO2)(v-dppf) [20].
An attempt to replace a Cl anion in the presence of
xyly isocyanide by NH4PF6 recovered the starting mate-
rials quantitatively. Extraction of Cl anions from the
ruthenium dppf or dpmf complexes appears to be more
difficult than those in other phosphine complexes, likely
resulting in steric demand.
3.5. Electrochemical reactions
The electrochemistry of compounds 2, 4 and 5 was
studied by cyclic voltammertry (CV), which was per-
formed in CH2Cl2/MeCN (a 1:1 ratio) at r.t. with 0.1 M
solution of [n-Bu4N][ClO4] as the supporting electrolyte,
and all E1/2 values are given versus the Fc/[Fc]+ [Fc=(p5-
C5H5)2Fe] redox couple (Table 7).
The CV showed one quasi-reversible and one irre-
versible waves in the positive region; the former is
assigned to the Fe(II)/Fe(III) couple and the latter to
oxidation of Ru(II) because such oxidation waves were
not observed in dpmf or dppf. The Fe(II)/Fe(III) couples
appeared at −40 mV for 2, 170 mV for 4 and 40 mV
for 5, respectively. In the bridged complexes the Fe(II)/
Fe(III) redox potentials were not significantly different
from those found in each free ligand. The redox reactions
of the dpmf complexes were performed much easily than
those of dppf ones, reflecting the electrochemical behav-
iors of free ligands. The chelated complexes showed
higher redox potentials in comparison with those of the
neutral complexes, depending on electron-deficient prop-
erty of 5 [2].
3.4.2. Complex 5b
The Ru atom of 5b is surrounded by an arene, one Cl
atom, and two P atoms of the chelated dppf, showing a
three-legged piano-stool structure (Fig. 4). Selected bond
lengths and angles are listed in Table 6.
˚
The Ru–Cl bond length of 2.396(3) A is not signifi-
cantly different from those of the v-bridged complexes,
˚
but the Ru–P bond lengths of 2.362(3) and 2.377(3) A
are slightly longer than those in neutral complexes 2 and
4, in spite of being a salt-like complex, because of the
steric demand of bulky chelated dppf. The average
˚
Ru–C(arene) length of 2.34 A is longer than those found
Table 6
in the bridged dppf and dpmf complexes, again due to
steric demand of chelated dppf. The average Fe–Cp
˚
Selected bond lengths (A) and angles (°) for 5b
˚
length is 2.03 A, being not significantly different from
˚
Bond lengths (A)
those of the bridged complexes. The P–Ru–Cl angles are
similar to those of the bridged complexes. The P–Ru–P
bite angle of 92.0(1)° is similar to that (91.6°) of
C5Me5RuO2(dppf-P,P%) [21]. The dihedral angle of 45°
between the two Cp rings is also similar to those of the
bridged complexes. The torsion angle of 3.9° is equal to
a synperiplanar conformation, which has been observed
in square-planar and three-legged piano-stool complexes
such as NiX2(dppf-P,P%) (X=Cl [19]; X=Br [22]) and
(p5-MeCp)Mn(CO)(dppf-P,P%)·CHCl3 [13,23].
Ru(1)–Cl(1)
Ru(1)–P(2)
Ru–C(arene)
2.396(3) Ru(1)–P(1)
2.377(3)
2.362(3)
2.03a
2.34a
Fe–C(Cp)
Bond angles (°)
Cl(1)–Ru(1)–P(1)
P(1)–Ru(1)–P(2)
Ru(1)–P(1)–C(17) 113.3(3)
C(1)–Fe–C(6) 105.4(5)
88.8(1)
92.0(1)
Cl(1)–Ru(1)–P(2)
Ru(1)–P(1)–C(6)
Ru(1)–P(2)–C(1)
86.4(1)
122.0(4)
121.5(4)
a Mean values between metal (Ru or Fe) and carbon atoms of the
arene or Cp ring.

232
J.-F. Mai, Y. Yamamoto / Journal of Organometallic Chemistry 560 (1998) 223–232
Table 7
Electrochemical data for complexes 2, 4 and 5a
Complex
2
4
5
E1/2(Fe)
Epa(Ru)
E1/2(Fe)
Epa(Ru)
E1/2(Fe)
Epa(Ru)
b
b
b
a
b
c
d
e
f
−35
170
111
168
168
185
195
393
373
420
393
388
414
−60
750
875
875
533
733
650
680
690
1300
b
1420
b
−40
−32
−20
785
1405
b
b
a Measured in a 0.1 M [n-Bu4N][ClO4]/MeCNꢁCH2Cl2 (1:1). Scan time: 0.10 V s−1 for 2 and 5, and 0.05 V s−1 for 4. E1/2 and Epa values are given
versus ferrocene/ferrocenium couple (E910 mV).
b Clear peak was not observed.
lic Chemistry, vol. 4, Pergamon, Oxford, 1982, p. 796. (b) H. Le
Bozec, D. Touchard, P.H. Dixneuf, Adv. Organomet. Chem. 28
(1989) 163.
In general, increased electron-donating ability of the
arenes affects the E1/2 values of redox potentials [24]. In
[(p6-arene)Ru(dppe)]2+ a linear fashion has been ob-
[4] (a) Y. Yamamoto, R. Satoh, M. Ohshima, F. Matsuo, C. Sudoh,
served between the E1/2 values for the Ru(II)/Ru(III)
couples and the number of methyl groups. The E1/2
values of the Fe(II)/Fe(III) couples for difference of the
arene rings in each series indicated a tendency to de-
crease with the number of methyl groups.
The oxidation waves were observed at ca. 800, 750
and 1400 mV for 2, 4 or 5, respectively, but their
coupled-reduction waves were not observed, suggesting
thermodynamic unstability of the oxidation products.
The dppf complexes in the bridged complexes were
oxidized much easily than those of the dpmf ones,
suggesting that the [dpmf]+ moiety has greater elec-
tron-acceptor ability than the [dppf]+ one.
J. Organomet. Chem. 489 (1995) C68. (b) Y. Yamamoto, R.
Satoh, F. Matsuo, C. Sudoh, T. Igoshi, Inorg. Chem. 35 (1996)
2329.
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Organometallics 3 (1984) 605. (c) M.A. Bennett, T.W. Metheson,
G.B. Robertson, A.K. Smith, P.A. Tucker, Inorg. Chem. 19
(1980) 1014.
[7] J.J. Bishop, A. Davison, M.L. Katcher, D.W. Lichtenberg, R.E.
Merrill, J.C. Smart, J. Organometal. Chem. 27 (1971) 241.
[8] D.T. Cromer, J.T. Waber, International Tables for X-ray Crys-
tallography, vol. IV, Kynoch Press, Birmingham, UK, Table
2.2A, 1974.
[9] J.A. Ibers, W.C. Hamilton, Acta Crystallogr. 17 (1964) 781.
[10] D.C. Creagh, W.J. McAuley, in: A.J.C. Wilson (Ed.), Interna-
tional Tables for X-ray Crystallography, vol. C, Kluwer, Boston,
MA, Table 4.2.6.8, 1992, pp. 219–222.
[11] J.G. Verkade, L.D. Quin, LD Phosphorous-31 NMR Spec-
toscopy in Stereochemical Analysis, VCH, Deerfield Beach, FL,
1987.
[12] (a) Y. Yamamoto, H. Yamazaki, Inorg. Chim. Acta 68 (1982) 75
and references therein. (b) F.A. Cotton, L.M. Daniels, C.A.
Murillo, D.J. Timmons, Chem. Commun. (1997) 1449.
[13] F. Estevan, P. Lahuerta, J. Latorre, A. Sanchez, C. Sieiro,
Polyhedron 6 (1987) 473.
4. Supplementary material available
Listings of atomic coordinates, hydrogen positional
parameters, isotropic and anisotropic parameters, and
bond lengths and angles and tables of observed and
calculated structure factors are available from the
authors.
[14] S. Onaka, T. Moriya, S. Takagi, A. Mizuno, H. Furuta, Bull.
Chem. Soc. Jap. 65 (1992) 1415.
[15] T.S.A. Hor, H.S.O. Chan, K.-L. Tan, Y.K. Phang, L.-K. Liu,
Y.-S. Wen, Polyhedron 10 (1991) 2437.
[16] L.-T. Phang, S.C.F. Au-Yeung, T.S.A. Hor, S.B. Khoo, Z.-X.
Zhou, T.C.W. Mak, J. Chem. Soc. Dalton Trans. (1993) 165.
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Acknowledgements
One of the authors (J.-F. Ma) was supported by a
grant from Toho University.
[18] S. Onaka, A. Mizuno, S. Takagi, Chem. Lett. (1989) 2037.
[19] U. Casellato, D. Ajo, G. Valle, B. Corain, B. Longato, R.
Graziani, J. Crystallogr. Spectrosc. Res. 18 (1988) 483.
[20] T.S.A. Hor, S.P. Neo, C.S. Tan, C.W. Mak, K.W.O. Leung,
R.-J. Wang, Inorg. Chem. 31 (1992) 4510.
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