Synthesis, structure and redox behaviour of tethered arene-ruthenium(II) complexes

Article abstract of DOI:10.1016/S0022-328X(01)00801-4

Tethered arene-ruthenium complexes [RuCl₂{η¹:η⁶-Me₂P(CH ₂)₃C₆H₅}], [RuCl₂{η¹:η⁶-Ph₂PCH ₂SiMe₂C₆H₅}] and [RuCl₂{η¹:η⁶-Ph₂P(CH ₂)₃(aryl)}] (aryl=2,4,6-C₆H₂Me₃, C₆Me₅) have been prepared by thermal displacement of methyl o-toluate from the appropriate P-donor derivatives of [RuCl₂(η⁶-1,2-MeC₆H₄CO ₂Me)]₂ and their structures determined by X-ray studies. The tethered complexes undergo reversible one-electron oxidation by cyclic voltammetry; the half-wave potentials are in the range 1.10-1.34 V versus AgAgCl and decrease with increasing methyl substitution on the arene.

Full text of DOI:10.1016/S0022-328X(01)00801-4

Journal of Organometallic Chemistry 629 (2001) 7–18
www.elsevier.com/locate/jorganchem
Synthesis, structure and redox behaviour of tethered
arene–ruthenium(II) complexes
Martin A. Bennett a,*, Alison J. Edwards a, Joanne R. Harper a,b, Tetyana Khimyak b,
Anthony C. Willis a
a Research School of Chemistry, Australian National Uni6ersity, Canberra ACT 0200, Australia
b Department of Chemistry, Uni6ersity of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
Received 11 January 2001; accepted 5 March 2001
Abstract
Tethered arene–ruthenium complexes [RuCl2{h1:h6-Me2P(CH2)3C6H5}], [RuCl2{h1:h6-Ph2PCH2SiMe2C6H5}] and
[RuCl2{h1:h6-Ph2P(CH2)3(aryl)}] (aryl=2,4,6-C6H2Me3, C6Me5) have been prepared by thermal displacement of methyl o-toluate
from the appropriate P-donor derivatives of [RuCl2(h6-1,2-MeC6H4CO2Me)]2 and their structures determined by X-ray studies.
The tethered complexes undergo reversible one-electron oxidation by cyclic voltammetry; the half-wave potentials are in the range
1.10–1.34 V versus Ag ꢀ AgCl and decrease with increasing methyl substitution on the arene. © 2001 Elsevier Science B.V. All
rights reserved.
Keywords: Arene; Phosphine; Chelating ligand; Ruthenium; Electrochemistry
1. Introduction
Much attention has been devoted to the chemistry of
tethered or strapped cyclopentadienyl complexes in
which one or more hydrogen atoms of the ring are
replaced by a connecting group to a pendant donor
We are interested in extending these studies to
atom that is capable of binding to the metal atom
strapped arene–ruthenium(II) complexes, from which it
[1–3]. Metal–arene complexes are less numerous and,
might be possible to generate, by one-electron oxida-
in general, less stable than their metal-cyclopentadienyl
tion, paramagnetic arene–ruthenium(III) (4d5) cations
counterparts, in part because the neutral arene is more
analogous to the chelation-stabilised alkene- and
readily lost from the coordination sphere. Thus, teth-
alkyne-complexes of bis(acetylacetonato)ruthenium-
ered arene ligands offer the possibility of stabilising
arene complexes for a range of metals and oxidation
states. Mirkin et al. [4–6] showed that the ligands
Ph2PCH2CH2XPh (X=CH2, O) form tethered arene–
(III), such as [Ru(acac)2(o-CH2ꢀCHC6H4NMe2)]+ [7]
and [Ru(acac)2(PhCꢁCC6H4NMe2)]+ [8]. During the
progress of our work, a number of reports on tethered
arene–ruthenium complexes have appeared in which a
rhodium(I) cations such as 1, which undergo reversible
variety of preparative methods have been used. Smith
electrochemical one-electron oxidation, presumably to
and Wright [9] reported that thermal displacement of
the corresponding arene–rhodium(II) dications; the lat-
ter are stabilised kinetically compared to their un-
strapped counterparts.
p-cymene (cym, 1,4-MeC6H4CHMe2) from the P-coor-
dinated derivative [RuCl2{Ph2P(CH2)3C6H5}(h6-cym)]
occurred in chlorobenzene at 130°C to give the tethered
complex [RuCl2{h1:h6-Ph2P(CH2)3C6H5}] in 50% yield;
a higher yield (75%) was achieved at the cost of prepar-
* Corresponding author. Tel.: +61-2-61253639; fax: +61-2-
61253216.
E-mail address: bennett@rsc.anu.edu.au (M.A. Bennett).
ative convenience by carrying out exhaustive bulk an-
odic oxidation of the starting P-complex. Subsequently,
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00801-4

8
M.A. Bennett et al. / Journal of Organometallic Chemistry 629 (2001) 7–18
(3)
2. Results and discussion
The compound C6H5(CH2)3PPh2 has been made pre-
viously by the reaction of 1-chloro-3-phenylpropane
with KPPh2 [4,5] or of 1-bromo-3-phenylpropane with
LiPPh2 [9]. We employed the alternative reaction of
Ph2PCl with the Grignard reagent derived from 1-
bromo-3-phenylpropane and extended this procedure to
prepare C6H5(CH2)3PMe2 by use of Me2PCl in place of
Ph2PCl. Similarly, we synthesised the compounds
C6Me5(CH2)3PPh2, 2,4,6-Me3C6H2(CH2)3PPh2 and
C6H5SiMe2CH2PPh2 from the reactions of Ph2PCl with
THF solutions of the Grignard reagents derived from
C6Me5(CH2)3Br, 2,4,6-Me3C6H2(CH2)3Br and C6H5Si-
Me2CH2Cl, respectively. Yields were generally between
40 and 80%; in the last case, some diphenylmethylphos-
phine was formed as a results of SiꢂCH2 bond cleavage
and was separated from C6H5SiMe2CH2PPh2 by vac-
uum sublimation.
In agreement with Therrien, Ward et al. [13–15], we
find that the RuCl2 complex of an aromatic ester, in
our case the methyl o-toluate complex [RuCl2(h6-1,2-
MeC6H4CO2Me)]2 (4) [20], is a suitably labile precursor
to tethered arene complexes. It reacts with the ligands
mentioned above in a 1:2 mole ratio in dichloro-
methane at room temperature to give quantitatively the
corresponding P-bonded adducts [RuCl2(h6-1,2-
MeC6H4CO2Me)(L)], which lose the methyl o-toluate
on heating in dichloromethane or dichloromethane-
THF at 120°C for 24–72 h (Eqs. (4–6)). The tethered
complexes can be isolated after chromatography of the
crude reaction mixtures in yields ranging from 60 to
80% for C6H5(CH2)3PR2 (R=Ph (5), Me (6)) and
C6H5SiMe2CH2PPh2 (7), through ca. 18% for 2,4,6-
Noels et al. [10,11] and Fu¨rstner et al. [12] indepen-
dently have obtained tethered complexes such as
[RuCl2{h1:h6-Cy2P(CH2)3C6H5}] in 80–90% yield by
heating the p-cymene P-donor complex in chloroben-
zene (Eq. (1)). Therrien, Ward and co-workers have
prepared tethered complexes containing the benzyl al-
cohols 1,2- or 1,3-C6H4(CH2OH)(CH2CH2PPh2) by dis-
placement of ethyl benzoate from its ruthenium(II)
complex [RuCl2(h6-C6H5CO2Et)]2 [13] (Eq. (2)) and
have used the same methodology to prepare tethered
arene complexes of ruthenium(II) that are configura-
tionally stable at the metal centre [14,15]. Rieger et al.
have also employed the ethyl benzoate complex as a
precursor to tethered arene–ruthenium(II) complexes
such as [RuCl2{h1:h6-R2P(CH2)2C6H5}] (R=Ph, Cy)
[16]. Silver ion-promoted abstraction of chloride ion
from ligand derivatives of the dimer [RuCl2{h6-
C6H5(CH2)3OH}]2 has been used to prepare tethered
complexes such as 2 and 3 [17]. Finally, in a recently
reported general method for preparing (CH2)3-strapped
arene complexes of ruthenium(II), the diphenylvinyl-
phosphine adduct of a methyl-substituted arene–ruthe-
nium(II) complex undergoes a base-promoted Michael
addition or hydroalkylation reaction (Eq. (3)) [18]. A
preliminary report of our work in this field was pre-
sented at the most recent International Conference on
Coordination Chemistry [19].
Me2C6H3(CH2)3PPh2
(8),
to
ca.
7%
for
C6Me5(CH2)3PPh2 (9). In the cases of 5–7 it is not
necessary to isolate the initially formed P-donor ad-
ducts; they can be generated in situ from complex 4 and
the ligand at room temperature.
(1)
(2)
(4)
(5)

M.A. Bennett et al. / Journal of Organometallic Chemistry 629 (2001) 7–18
9
doublet at l 5.33 (J=6.5 Hz) and a multiplet at l 6.46.
These can be attributed to an intermediate [RuCl2(h6-
C6D5Cl){Ph2P(CH2)3C6H5}] which, however, decom-
posed on attempted isolation.
The NMR spectra of the methyl o-toluate complexes
show, in addition to resonances characteristic of the
CO2Me group, resonances due to the four protons of
the coordinated arene ring in the region l 4.2–6.2 and
corresponding resonances due to the aromatic carbon
atoms in the region l 76–115. The P-methyl groups in
[RuCl2(h6-1,2-MeC6H4CO2Me){Me2P(CH2)3C6H5}] are
inequivalent because of the planar chirality of the h6-
methyl o-toluate [20] and appear as two doublets in the
(6)
The formation of the tethered complex [RuCl2{h1:h6-
Ph2P(CH2)3C6H5}] (5) seems to be favoured by the
presence of a small amount of THF, which slightly
increases the yield and shortens the reaction time from
72 to 36 h. In the case of C6Me5(CH2)3PPh2, the yield
of 9 can be increased to 35% by the use of di-n-butyl
ether in place of dichloromethane. This behaviour is
reminiscent of the effect of ether solvents in the synthe-
sis of (h6-arene) chromium tricarbonyls [21,22]. At-
tempts to form the tethered complexes 5 and 6 by
UV-irradiation of solutions of the h6-methyl o-toluate
complexes at room temperature led only to decomposi-
tion, with loss of the aromatic ester and formation of
the phosphine oxide.
1
13C{1H}- and H-NMR spectra. The IR spectra of the
complexes contain typical w(CO2) ester absorptions at
ca. 1720 and 1260 cm−1, and one strong, broad band
centred at 280–290 cm−1, which presumably contains
the two expected w(RuCl) absorptions.
1
The H- and 13C{1H}-NMR spectra of the tethered
complexes provide clear evidence for the coordination
1
of the arene group of the P-donor ligands. Thus, the H
spectra of 5, 6 and 7 contain three resonances in a 2:2:1
intensity ratio due to the C6H5 protons in the region l
4.9–6.3. The low frequency shifts are mirrored in the
13C{1H}-NMR spectra, which show four arene reso-
nances in the region l 80–100. Similarly, in complex 8,
the equivalent mesityl aromatic protons appear as a
singlet at l 5.25, cf. l 6.69 in the precursor methyl
o-toluate complex. The far IR spectra of 5, 6, 7 and 9
show the expected two strong w(RuCl) bands at ca. 300
and 280 cm−1. The singlet in the 31P{1H}-NMR spec-
tra of each of the tethered complexes containing PPh2
groups appears in the region l 22–29, the chemical
shift being similar to, though distinguishable from, that
of the precursor methyl o-toluate complexes. The 31P
chemical shifts of the methyl o-toluate and tethered
complexes of C6H5(CH2)3PMe2 are also similar (l 15.7
and 13.7, respectively).
We were unable to reproduce Smith and Wright’s
preparation of
5
from the p-cymene complex
[RuCl2(h6-1,4-MeC6H4CHMe2){Ph2P(CH2)3C6H5}] in
chlorobenzene at 130°C [9], and use of dichloromethane
containing THF at 120°C was also unsuccessful. When
the adduct was heated in an NMR tube at 130°C in
C6D5Cl, displacement of the p-cymene was observed
but the 31P-NMR singlet of the tethered complex at l
22.2 was not present. There was a broad 31P-NMR
2
singlet at l 29.6 and the H-NMR spectrum showed a
An indication of the stability of the tethered com-
plexes is that they all show parent ions in their electron-
impact (EI) or fast-atom-bombardment (FAB) mass
spectra. In contrast, for the methyl o-toluate com-
plexes, the highest mass ion is usually [M−Cl]+ or, in
the case of C6H5SiMe2CH2PPh2, [M−arene]+.
The molecular structures of the tethered RuCl2 com-
plexes 6–9 have been determined by single crystal
X-ray analysis and are shown with atom labelling in
Figs. 1–4, respectively. Selected bond distances and
angles are in Tables 1–4. The complexes show the
expected half-sandwich geometry, the RuꢂP, RuꢂCl
and RuꢂC(arene) distances being similar to those previ-
ously reported for related tethered complexes such as 5
[9,18] and [RuCl2{h1:h6-Cy2P(CH2)3C6H5}] [12]. In all
the complexes containing aryl(CH2)3PR2, the
Fig. 1. ORTEP drawing of 6 with 30% probability thermal ellipsoids.
Hydrogen atoms have been omitted for clarity.

10
M.A. Bennett et al. / Journal of Organometallic Chemistry 629 (2001) 7–18
rings in 6–9 are almost planar, the RuꢂC(arene) dis-
,
tances trans to the P-donor (2.24–2.28 A) are signifi-
cantly greater than those trans to the RuꢂCl bonds
,
(2.16–2.21 A), reflecting the relative trans-influences of
Cl and PR3; the same effect has been observed for the
non-tethered complex [RuCl2(PMePh2)(h6-C6H6)] [23].
All the tethered complexes show fully reversible,
one-electron, RuII,III redox couples in CH2Cl2 (Table 5).
Our E1/2 value for 5 (+1.32 V vs Ag ꢀ AgCl) seems to
Fig. 2. ORTEP drawing of 7 with 30% probability thermal ellipsoids.
Hydrogen atoms have been omitted for clarity.
Fig. 4. ORTEP drawing of 9 with 50% probability thermal ellipsoids.
Hydrogen atoms have been omitted for clarity.
Table 1
,
Selected bond lengths (A) and angles (°) for 6
Fig. 3. ORTEP drawing of 8 with 50% probability thermal ellipsoids.
Hydrogen atoms, labels C(13)ꢂC(18) and the solvent molecule
(CH2Cl2) have been omitted for clarity.
Molecule 1
Molecule 2
Ru(1)ꢂCl(1)
Ru(1)ꢂCl(2)
Ru(1)ꢂP(1)
Ru(1)ꢂC(4)
Ru(1)ꢂC(5)
Ru(1)ꢂC(6)
Ru(1)ꢂC(7)
Ru(1)ꢂC(8)
Ru(1)ꢂC(9)
PꢂC
2.405(2)
2.421(2)
2.322(3)
2.193(8)
2.185(9)
2.181(9)
2.257(9)
2.257(9)
2.170(9)
1.79(1)–
1.82(1)
Ru(2)ꢂCl(3)
Ru(2)ꢂCl(4)
Ru(2)ꢂP(2)
Ru(2)ꢂC(15)
Ru(2)ꢂC(16)
Ru(2)ꢂC(17)
Ru(2)ꢂC(18)
Ru(2)ꢂC(19)
Ru(2)ꢂC(20)
PꢂC
2.415(2)
2.421(3)
2.303(2)
2.194(9)
2.189(9)
2.158(9)
2.253(9)
2.24(1)
trimethylene strap allows simultaneously a close to
regular trigonal geometry for the RuCl2P fragment and
coplanarity of the benzylic carbon atom with the car-
bon atoms of the attached arene, without distortion of
bond lengths or angles in the tether. In contrast, in 7
the presence of the two-atom strap causes a bending of
the SiꢂC(C6H5) bond out of the aromatic plane by ca.
14°. In complexes 6, 7 and 9, the trigonal RuCl2P
fragment adopts a staggered arrangement relative to the
carbon atoms of the aromatic ring, whereas in complex
8 it lies about half-way between the eclipsed and stag-
gered conformations. Although the complexed aromatic
2.182(9)
1.79(1)–1.82(1)
CꢂC(arene)
1.36(1)–
1.42(1)
CꢂC(arene)
1.36(2)–1.43(1)
Cl(1)ꢂRu(1)ꢂCl(2) 87.68(9)
Cl(1)ꢂRu(1)ꢂP(1)
Cl(2)ꢂRu(1)ꢂP(1)
Cl(3)ꢂRu(2)ꢂCl(4) 87.8(1)
Cl(3)ꢂRu(2)ꢂP(2) 89.17(8)
Cl(4)ꢂRu(2)ꢂP(2) 84.72(9)
89.34(9)
83.83(9)

M.A. Bennett et al. / Journal of Organometallic Chemistry 629 (2001) 7–18
11
Table 2
Selected bond lengths (A) and angles (°) for 7
C6Me6)(PMe3)] to be +1.05 V (similar values for re-
lated complexes have been reported [24]), indicating
that although the tether may inhibit arene dissociation
it also tends to stabilise RuII relative to RuIII. The
potentials in our complexes are clearly too high to
permit isolation of the derived arene–ruthenium(III)
cations and we are currently investigating the prepara-
tion of more electron-rich derivatives, such as dimethyl-
ruthenium(II) complexes, containing tethered arenes.
,
Ru(1)ꢂCl(1)
Ru(1)ꢂP(1)
Ru(1)ꢂC(5)
Ru(1)ꢂC(7)
Ru(1)ꢂC(9)
2.4050(7)
2.3526(7)
2.180(2)
2.250(3)
2.145(3)
Ru(1)ꢂCl(2)
Ru(1)ꢂC(4)
Ru(1)ꢂC(6)
Ru(1)ꢂC(8)
PꢂC
2.4159(7)
2.180(2)
2.193(3)
2.246(3)
1.818(2)
–1.831(2)
1.405(4)
SiꢂC
1.847(3)–
1.902(3)
CꢂC(arene)
–1.436(4)
Cl(1)ꢂRu(1)ꢂCl(2)
Cl(2)ꢂRu(1)ꢂP(1)
89.90(3)
94.29(3)
Cl(1)ꢂRu(1)ꢂP(1)
84.26(2)
3. Experimental
3.1. General considerations
Table 3
,
Selected bond lengths (A) and angles (°) for 8
All reactions were carried out under purified nitrogen
or argon with use of standard Schlenk techniques and
solvents were purified and deoxygenated before use.
The compounds 1-bromo-3-phenylpropanol, bromome-
Ru(1)ꢂCl(1)
Ru(1)ꢂP(1)
Ru(1)ꢂC(2)
Ru(1)ꢂC(4)
Ru(1)ꢂC(6)
2.4159(10) Ru(1)ꢂCl(2)
2.3230(10) Ru(1)ꢂC(1)
2.183(4)
2.262(4)
2.200(4)
2.4425(10)
2.212(4)
2.282(4)
2.203(4)
1.828(4)–
1.845(4)
Ru(1)ꢂC(3)
Ru(1)ꢂC(5)
PꢂC
sitylene,
chlorodiphenylphosphine,
1,3-dibromo-
propane, a-phellandrene, pentamethylbenzene, o-toluic
acid, (chloromethyl)dimethylphenylsilane and hydrated
ruthenium chloride were obtained from commercial
suppliers. Bromopentamethylbenzene was obtained by
bromination of pentamethylbenzene [25]. The salt [n-
Bu4N]PF6 was obtained by neutralising commercial
aqueous [n-Bu4N]OH with HPF6; it was recrystallised
three times from MeOH–H2O (4:1) and dried in vacuo
for 8 h. Chlorodimethylphosphine was prepared in
three steps from PSCl3 [26–28]. The complex
[RuCl2(h6-1,2-MeC6H4CO2Me)]2 (4) was prepared as
described previously [20].
NMR spectra were recorded either on Varian XL-
200E, Varian Gemini 300-BB or Varian VXR 300
spectrometers in Canberra or on Bruker DPX-400 or
Bruker DRX-500 spectrometers in Cambridge. The
chemical shifts (l) for 1H and 13C were measured
relative to residual signals of the solvents and to exter-
CꢂC(arene)
1.393(6)–
1.439(6)
Cl(1)ꢂRu(1)ꢂCl(2)
Cl(2)ꢂRu(1)ꢂP(1)
87.52(4)
90.34(4)
Cl(1)ꢂRu(1)ꢂP(1)
86.35(4)
Table 4
,
Selected bond lengths (A) and angles (°) for 9
Ru(1)ꢂCl(1)
Ru(1)ꢂP(1)
Ru(1)ꢂC(5)
Ru(1)ꢂC(7)
Ru(1)ꢂC(9)
2.4016(12) Ru(1)ꢂCl(2)
2.2995(14) Ru(1)ꢂC(4)
2.249(5)
2.284(5)
2.182(5)
2.4163(12)
2.203(5)
2.201(5)
2.285(5)
1.822(5)–
1.834(5)
Ru(1)ꢂC(6)
Ru(1)ꢂC(8)
PꢂC
CꢂC(arene)
1.394(7)–
1.454(7)
Cl(1)ꢂRu(1)ꢂCl(2)
Cl(2)ꢂRu(1)ꢂP(1)
88.58(4)
82.29(4)
Cl(1)ꢂRu(1)ꢂP(1)
88.83(5)
Table 5
Electrochemical data for the tethered complexes 5–9
be in fair agreement with the values reported by Smith
and Wright [9] (+1.34 V vs SCE) and by Ghebreyessus
and Nelson [18] (+0.74 V vs ferrocene/ferrocenium),
though exact comparison is difficult because we used a
non-aqueous Ag ꢀ AgCl reference electrode. The poten-
tials are reduced by increasing methyl substitution in
the arene ring, as observed also in tethered arene–
rhodium and non-tethered arene–ruthenium systems
[6,24], and by replacement of PPh2 by the more elec-
tron-donating PMe2. The potentials are significantly
greater than those of analogous unstrapped complexes,
e.g. we find E1/2 versus Ag ꢀ AgCl for [RuCl2(h6-
Compound
E1/2 (V)
DEp (mV s−1
)
Behaviour
5
6
7
8
9
+1.32 a
+1.26 a
+1.34 a
+1.20 b
+1.10 b
60
70
60
80
80
Reversible
Reversible
Reversible
Reversible
Reversible
All electrode potentials were referenced to an Ag ꢀ AgCl reference
electrode.
a Experiments were recorded at 100 mV s−1 in 0.5 M [Bu4NPF6]/
CH2Cl2 solution at 293 K.
b Experiments were recorded at 100 mV s−1 in 0.2 M [Bu4NPF6]/
CH2Cl2 solution at 253 K.

12
M.A. Bennett et al. / Journal of Organometallic Chemistry 629 (2001) 7–18
nal 85% H3PO4 for 31P-NMR. The 31P{1H}-NMR reso-
nances of all the compounds described here were sin-
glets. Carbon atoms and the attached hydrogen atoms
are numbered as shown below.
reaction mixture was allowed to cool to room tempera-
ture (r.t.), poured on to a slurry of ice/conc. HCl (500
ml), and the aqueous phase extracted with Et2O (6×
100 ml). The organic phase was washed with 1 M KOH
(6×100 ml) and dried (Na2SO4). The solvent was
removed by evaporation and the product was precipi-
tated by addition of EtOH at −20°C to afford the title
compound as a white solid, m.p. 34–38°C (7.54 g,
63%). 1H-NMR (400 MHz, CDCl3): l 2.00 (m, 2H,
CH2CH2CH2), 2.21 (s, 6H, C2ꢂMe), 2.22 (s, 3H,
C4ꢂMe), 2.25 (s, 6H, C3ꢂMe), 2.83 (m, 2H, CH2C6Me5),
3.51 (t, 2H, J=6.5 Hz, CH2Br). 13C{1H}-NMR (75.4
MHz, CDCl3): l 16.41 (C2ꢂMe), 16.80 (C4ꢂMe), 16.85
(C3ꢂMe), 29.30 (CH2CH2CH2), 32.74 (CH2C6Me5),
34.10 (CH2Br), 131.71 (C4), 132.62 (C2 or C3), 132.87
(C3 or C2), 134.61 (C1). IR (KBr, cm−1): 553 m
[w(CꢂBr)]. EIMS; m/z: 270 [M+]. High resolution MS;
m/z, Found: 268.083032, 270.080666; Calc. for
Fast Atom Bombardment (FAB) mass spectra were
measured either on a VG ZAB2-SEQ spectrometer in
Canberra or on a MSI Concept IH spectrometer in
Cambridge, using either 3-nitrobenzyl alcohol or 3-ni-
tro-octylphenylether as a matrix. Electron Impact (EI)
mass spectra were measured either on a VG Micromass
7070 spectrometer in Canberra or on a Kratos Concept
IH spectrometer in Cambridge. Gas chromatograph–
mass spectra (GC–MS) were obtained on a 5970 MSD
Hewlett–Packard BP1 Detector in Canberra, using a
12.5 m long column.
79
81
C14H Br and C14H Br: 268.082662, 270.080616, re-
21
21
spectively. Anal. Found: C, 62.13; H, 7.91. Calc. for
C14H21Br: C, 62.46; H, 7.86%.
Infrared spectra in the range 4000–400 cm−1 were
measured as KBr discs or Nujol mulls on a Perkin–
Elmer Spectrum One spectrometer (Canberra) or a
Perkin–Elmer Paragon 1000 spectrometer (Cambridge).
Spectra in the range 500–150 cm−1 were recorded on a
Perkin–Elmer FT-1800 instrument in Canberra.
Microanalyses were carried out at the Analytical
Services Unit, ANU, Canberra or at the University of
Cambridge Chemical Laboratory. Cyclic voltammetry
(CV) and alternating current voltammetry (ACV) mea-
surements were performed on a PAR-170 Electrochemi-
3.3. Preparation of 1-bromo-3-(mesityl)propane,
2,4,6-Me3C6H2(CH2)3Br
This compound was prepared from mesityl magne-
sium bromide and 1,3-dibromopropane in a similar
way. 1H-NMR (300 MHz, CDCl3): l 1.99 (m, 2H,
CH2CH2CH2), 2.24 (s, 3H, C4ꢂMe), 2.29 (s, 6H,
C2ꢂMe), 2.73 (m, 2H, CH2C6H2Me3), 3.50 (t, 2H, J=
6.5 Hz, CH2Br), 6.83 (s, 2H, H3). High resolution MS;
79
17
m/z, Found: 242.04972, 242.04785; Calc. for C12H Br
and C12H Br: 240.05136, 242.04945, respectively.
cal System with use of
a
Ag ꢀ AgCl ꢀ acetonitrile
81
17
reference electrode as described elsewhere [29]. Under
these conditions ferrocene and decamethylferrocene
were oxidised at +0.55 and −0.05 V, respectively.
Melting points (m.p.) were determined on a Gal-
lenkamp apparatus and are uncorrected.
3.4. Preparation of (3-phenylpropyl)dimethylphosphine,
Me2P(CH2)3C6H5
1-Bromo-3-phenylpropane (15.3 ml, 0.10 mol) was
added dropwise to a stirred suspension of magnesium
(2.57 g, 0.11 mol) in dry THF (30 ml). Dry THF (20
ml) was added and the reaction mixture was heated at
reflux for 30 min. The solution was allowed to cool,
transferred to a separate flask with Et2O (30 ml),
stirred, and treated dropwise with chlorodimethylphos-
phine (7.5 ml, 0.095 mol) in Et2O (40 ml) at 0°C. The
mixture was heated at reflux for 30 min, cooled to 0°C,
and treated dropwise with degassed 10% aqueous
NH4Cl (30 ml). The mixture was allowed to come to
r.t., the organic phase removed, and the aqueous phase
extracted with Et2O (3×50 ml). The combined organic
phases were dried (Na2SO4), solvents were removed in
vacuo, and the residue was distilled under reduced
pressure to afford the title compound as a colourless
3.2. Preparation of 1-bromo-3-(pentamethylphenyl)-
propane, C6Me5(CH2)3Br
This procedure is based on that described in Ref.
[30]. A solution of bromopentamethylbenzene (10 g, 44
mmol) in dry THF (110 ml) was added dropwise to a
stirred suspension of magnesium (1.72 g, 70 mmol) in
dry THF (10 ml). The reaction was initiated with a
small amount of reacting Mg–BrCH2CH2Br and the
mixture was heated at reflux for 1 h. The solution was
allowed to cool, transferred to a separate dropping
funnel with dry THF (20 ml), and added dropwise to a
mixture of 1,3-dibromopropane (6.7 ml, 66 mmol), dry
HMPA (4 ml), and freshly prepared CuBr (320 mg, 5
mol% to the Grignard reagent) in dry THF (20 ml) at
reflux. Dry THF (20 ml) was then added and the
reaction mixture was heated at reflux for 20 h. The
1
liquid, b.p. 86–88°C/1.5 mm (8.60 g, 48%). H-NMR
(300 MHz, CD2Cl2): l 1.07 (dd, 6H, J=2, 0.5 Hz,
Me2P), 1.46 (m, 2H, CH2CH2CH2), 1.83 (m, 2H,

M.A. Bennett et al. / Journal of Organometallic Chemistry 629 (2001) 7–18
13
CH2P), 2.78 (t, 2H, J=8 Hz, CH2C6H5), 7.25–7.30 (m,
3H, H3, H4), 7.35–7.40 (m, 2H, H2). 13C{1H}-NMR
CH2CH2CH2), 2.19 (s, 6H, C2ꢂMe), 2.20 (s, 3H,
C4ꢂMe), 2.27–2.33 (m, 2H, CH2P), 2.70 (t, 2H, J=8
Hz, CH2C6H2Me3), 6.77 (s, 2H, H3), 7.30–7.35 (m,
6H), 7.40–7.45 (m, 4H, PPh2). 13C{1H}-NMR (100.6
MHz, CD2Cl2): l 19.71 (C2ꢂMe), 20.73 (C4ꢂMe), 25.78
(d, 2JPC=16 Hz, CH2CH2CH2), 28.42 (d, 1JPC=12 Hz,
1
(75.4 MHz, CD2Cl2): l 14.25 (d, JPC=13 Hz, Me2P),
2
1
28.14 (d, JPC=13 Hz, CH2CH2CH2), 32.08 (d, JPC
=
10 Hz, CH2P), 37.84 (d, 3JPC=11 Hz, CH2C6H5),
126.12 (C4), 128.66 (C2 or C3), 128.87 (C3 or C2), 142.73
(C1). 31P{1H}-NMR (121.5 MHz, CD2Cl2): l −51.6.
EIMS; m/z: 179 [M+]. High resolution MS; m/z,
Found: 180.106818; Calc. for C11H17P: 180.106789.
Anal. Found: C, 73.11; H, 9.27. Calc. for C11H17P: C,
73.31; H, 9.51%.
3
CH2P), 30.99 (d, JPC=13 Hz, CH2C6H2Me3), 128.59,
128.65, 128.72 (C2–4), 128.94, 132.88 (d, JPC=19 Hz),
135.95 (PPh2), 136.00 (C1), 139.36 (d, JPC=14 Hz,
PPh2). 31P{1H}-NMR (121.5 MHz, CD2Cl2): l −16.5.
EIMS; m/z: 346 [M+]. High resolution MS; m/z,
Found: 346.18562; Calc. for C24H27P: 346.18504.
3.5. Preparation of (3-phenylpropyl)diphenylphosphine,
Ph2P(CH2)3C6H5
3.7. Preparation of
(3-pentamethylphenylpropyl)diphenylphosphine,
Ph2P(CH2)3C6Me5
This compound was prepared in 76% yield as a white
solid, m.p. 56–58°C, from 1-bromo-3-phenylpropane
and chlorodiphenylphosphine in a similar way. 1H-
This compound was prepared from 1-bromo-3-(pen-
tamethyl)propane (4.03 ml, 15 mmol), magnesium (0.37
g, 15 mmol) and chlorodiphenylphosphine (2.6 ml, 15
mmol) in a similar way. In the final step the residue
obtained by evaporation of the combined organic layers
was washed with cold ethanol to give the title com-
pound as a white solid, m.p. 90–92°C (4.33 g, 77%).
NMR (300 MHz, CD2Cl2):
l
1.76 (m, 2H,
CH2CH2CH2), 2.08 (m, 2H, CH2P), 2.75 (t, 2H, J=8
Hz, CH2C6H5), 7.15–7.45 (m, 15H, PPh2). 13C{1H}-
2
NMR (75.4 MHz, CD2Cl2); l 27.59 (d, JPC=12 Hz,
1
CH2CH2CH2), 28.10 (d, JPC=17 Hz, CH2P), 37.43 (d,
3JPC=13 Hz, CH2C6H5), 126.13 (C4), 128.34 (d, JPC
=
5 Hz), 128.79 (d, JPC=3 Hz), 132.98 (d, JPC=19 Hz),
139.36 (d, JPC=14 Hz, PPh2), 142.29 (C1). 31P{1H}-
NMR (121.5 MHz, CD2Cl2): l −16.2. GC–MS; m/z:
303 [M+]. Anal. Found: C, 82.68; H, 6.66; P, 10.34.
Calc. for C21H21P: C, 82.87; H, 6.95; P, 10.18%.
1H-NMR (300 MHz, CD2Cl2):
l 1.54 (m, 2H,
CH2CH2CH2), 2.15 (s, 6H, C2ꢂMe), 2.17 (s, 6H,
C3ꢂMe), 2.19 (s, 3H, C4ꢂMe), 2.22–2.25 (m, 2H,
CH2P), 2.80 (t, 2H, J=8 Hz, CH2C6Me5), 7.30–7.35
(m, 6H), 7.40–7.45 (m, 4H, PPh2). 13C{1H}-NMR (75.4
MHz, CD2Cl2): l 16.48 (C2ꢂMe), 16.86 (C3ꢂMe,
2
C4ꢂMe), 26.49 (d, JPC=16 Hz, CH2CH2CH2), 28.47
3.6. Preparation of (3-mesitylpropyl)diphenylphosphine,
Ph2P(CH2)3-2,4,6-C6H2Me3
(d, 1JPC=12 Hz, CH2P), 32.34 (d, 3JPC=13 Hz,
CH2C6Me5), 128.64 (C4), 128.75 (d, JPC=3 Hz), 131.61
(C2, C3), 132.53 (d, JPC=3 Hz), 132.97 (d, JPC=18
Hz), 135.98 (C1), 139.50 (d, JCP=14 Hz, PPh2).
31P{1H}-NMR (121.5 MHz, CD2Cl2): l −16.5. EIMS;
m/z: 374 [M+]. High resolution MS; m/z, Found:
374.217049; Calc. for C26H31P: 374.216340.
A solution of 1-bromo-3-(mesityl)propane (5.97 g,
24.7 mmol) in THF (20 ml) was added dropwise to a
stirred suspension of magnesium (0.66 g, 27.1 mmol) in
dry THF (10 ml). The reaction was initiated with a
small amount of reacting Mg–BrCH2CH2Br. The reac-
tion mixture was heated at reflux for 30 min, allowed to
cool, and transferred to a separate flask with Et2O (20
ml). Chlorodiphenylphosphine (4.2 ml, 23.4 mmol) in
Et2O (10 ml) was added dropwise to the stirred Grig-
nard reagent at 0°C. After addition of Et2O (50 ml), the
reaction mixture was allowed to warm to r.t., heated at
reflux for 1 h, cooled to 0°C, stirred, and treated
dropwise with degassed 10% aqueous NH4Cl (30 ml).
The organic phase was removed and the aqueous layer
extracted with Et2O (4×50 ml). The combined organic
layers were dried (Na2SO4) and the solvents were re-
moved in vacuo. The residue was purified by column
chromatography (activity I acidic alumina, CH2Cl2).
The solvent was removed in vacuo to afford the title
compound as a white solid, m.p. 74–76°C (7.41 g,
3.8. Preparation of
(phenyldimethylsilyl)methyldiphenylphosphine,
Ph2PCH2SiMe2C6H5
(Chloromethyl)dimethylphenylsilane (3.9 ml, 22
mmol) was added dropwise to a stirred suspension of
magnesium (0.56 g, 23 mmol) in dry THF (10 ml).
After addition of THF (10 ml), the mixture was heated
at reflux for 30 min, allowed to cool, transferred to a
separate flask with Et2O (20 ml), stirred, and treated
dropwise at 0°C with a solution of chlorodiphenylphos-
phine (3.7 ml, 21 mmol) in Et2O (15 ml). After addition
of more Et2O (10 ml), the solution was heated at reflux
for 30 min and worked up as described above to give a
sticky solid that contained Ph2PCH2SiMe2C6H5 and
1
80%). H-NMR (300 MHz, CD2Cl2): l 1.54 (m, 2H,

14
M.A. Bennett et al. / Journal of Organometallic Chemistry 629 (2001) 7–18
Ph2MeP in ca. 7:1 ratio, as shown by 31P-NMR spec-
troscopy. The minor product was removed by sublima-
tion (50°C, 7.10−6 mm) on to a liquid nitrogen-cooled
probe and the residue was recrystallised from hot etha-
nol (5 ml) to give the title compound as a white solid,
m.p. 62–64°C (3.18 g, 44%). 1H-NMR (300 MHz,
CD2Cl2): l 0.17 (s, 6H, Me2Si), 1.62 (d, 2H, J=1 Hz,
CH2P), 7.30–7.35, 7.40–7.50 (m, 15H, H2–4, PPh2).
13C{1H}-NMR (75.4 MHz, CD2Cl2): l −1.76 (d,
4JPC=4 Hz, Me2Si), 14.02 (d, 1JPC=30 Hz, CH2P),
128.01 (C4), 128.52 (C2 or C3), 128.65 (d, JPC=6 Hz,
PPh2), 129.28 (C3 or C2), 132.77 (d, JPC=20 Hz, PPh2),
133.85 (C1), 141.53 (d, JPC=15 Hz, PPh2). 31P{1H}-
NMR (121.5 MHz, CD2Cl2): l −22.3. EIMS; m/z: 333
[M+]. High resolution MS; m/z, Found: 333.123063;
Calc. for C21H23PSi: 333.122843.
5.38 (q, 1H, J=6 Hz), 6.17 (d, 1H, J=5 Hz,
C6H4CO2Me), 6.90–7.80 (m, 15H, PPh2). 13C{1H}-
NMR (75.4 MHz, CDCl3): l 19.25 (MeC6H4), 23.72 (d,
2JPC=30 Hz, CH2CH2CH2), 24.95 (d, 1JPC=7 Hz,
CH2P), 36.46 (d, 3JPC=13 Hz, CH2C6H5), 52.54
1
(CO2Me), 79.17, 85.44, 89.16, 94.44, 113.56 (d, JPC=4
Hz, MeC6H4CO2Me), 125.45 (C4), 127.87, 128.06,
128.13 (C2, C3, PPh2), 130.46 (d, JPC=15 Hz), 132.44
(d, JPC=9 Hz), 132.84 (d, JPC=9 Hz, PPh2), 141.01
(C1), 164.69 (CO2Me). 31P{1H}-NMR (121.5 MHz,
CDCl3): l 27.8. IR (KBr and polythene, cm−1): 1727
m, 1261 m [w(CO2)], 290 s [w(RuꢂCl)]. FABMS; m/z:
591 [M−Cl]+. Anal. Found: C, 57.59; H, 5.35; P, 4.79.
Calc. for C30H31Cl2O2PRu: C, 57.51; H, 4.99; P, 4.94%.
3.11. [RuCl2(p6-1,2-MeC6H4CO2Me){Ph2PCH2SiMe2-
C6H5}], orange solid (96% yield)
3.9. Preparation of P-donor complexes[RuCl2-
(p6-1,2-MeC6H4CO2Me){Me2P(CH2)3C6H5}]
1H-NMR (300 MHz, CDCl3): l −0.19 (s, 6H,
Me2Si), 2.33 (d, 2H, JPC=8 Hz, CH2P), 2.41 (s, 3H,
MeC6H4), 3.75 (s, 3H, CO2Me), 4.23 (t, 1H, J=5 Hz),
4.69 (d, 1H, J=5 Hz), 5.31 (q, 1H, J=5 Hz), 6.13 (d,
1H, J=5 Hz, C6H4CO2Me), 7.10–7.85 (m, 15H, PPh2).
13C{1H}-NMR (75.4 MHz, CDCl3): l −1.35 (d,
4JPC=6 Hz, Me2Si), 11.30 (d, 1JPC=25 Hz, CH2P),
19.59 (MeC6H4), 52.73 (CO2Me), 79.31, 85.08 (d,
A
solution containing [RuCl2(h6-1,2-MeC6H4-
CO2Me)]2 (4) (46 mg, 0.071 mmol) and 3-(phenyl-
propyl)dimethylphosphine (30 mg, 0.17 mmol) in
CH2Cl2 (10 ml) was stirred for 1 h and filtered through
Celite, which was then washed with CH2Cl2 (2×20 ml).
Addition of hexane (40 ml) to the filtrate and removal
of the solvents in vacuo gave the title compound as an
JPC=4 Hz), 89.75, 94.67, 113.74 (d, JPC=4 Hz,
1
orange-pink solid (61 mg, 85%). H-NMR (300 MHz,
MeC6H4CO2Me), 127.43 (C4), 128.12 (d, JPC=10 Hz,
PPh2), 128.63 (C2 or C3), 130.61 (d, JPC=11 Hz),
132.35 (d, JPC=9 Hz), 132.77 (d, JPC=9 Hz, PPh2),
133.13 (C3 or C2), 138.64 (d, JPC=3 Hz, C1), 165.06
(CO2Me). 31P{1H}-NMR (121.5 MHz, CDCl3): l 26.3.
IR (KBr and polythene, cm−1): 1722 m, 1258 m
[w(CO2)], 288 s [w(RuꢂCl)]. FABMS; m/z: 506 [M−
arene]+. Anal. Found: C, 54.54; H, 5.04; P, 4.52. Calc.
for C30H33Cl2O2PRuSi: C, 54.88; H, 5.07; P, 4.72%.
CDCl3): l 1.53 (overlapping d, 6H, sep=10 Hz, Me2P),
1.85 (m, 2H, CH2CH2CH2), 2.04 (m, 2H, CH2P), 2.49
(s, 3H, MeC6H4), 2.70 (m, 2H, CH2C6H5), 3.83 (s, 3H,
CO2Me), 4.78 (t, 1H, J=5.5 Hz), 5.38 (d, 1H, J=5.5
Hz), 5.54 (m, 1H), 6.21 (dd, 1H, J=5.5, 3.5 Hz,
C6H4CO2Me), 7.15–7.20 (m, 3H), 7.25–7.30 (m, 2H,
C6H5). 13C{1H}-NMR (75.4 MHz, CDCl3): l 12.33 (d,
1JPC=35 Hz, MeMeP), 13.25 (d, 1JPC=34 Hz,
MeMeP), 19.84 (MeC6H4), 25.61 (d, 2JPC=4 Hz,
1
CH2CH2CH2), 30.38 (d, JPC=30 Hz, CH2P), 36.83 (d,
3JPC=13 Hz, CH2C6H5), 52.77 (CO2Me), 76.06, 87.74
(d, JPC=8 Hz), 90.57, 91.37, 102.83, 114.84 (d, JPC=5
Hz, MeC6H4CO2Me), 126.25, 128.54, 141.09 (C6H5),
165.78 (CO2Me).31P{1H}-NMR (121.5 MHz, CDCl3): l
15.7. IR (KBr and polythene, cm−1): 1722 m, 1259 m
[w(CO2)], 279 s [w(RuꢂCl)]. FABMS; m/z: 467 [M−
Cl]+. Anal. Found: C, 47.43; H, 5.62; P, 6.29. Calc. for
C20H27Cl2O2PRu: C, 47.82; H, 5.42; P, 6.17%.
3.12. [RuCl2(p6-1,2-MeC6H4CO2Me){Ph2P(CH2)3-
C6Me5}], orange solid (98% yield)
1H-NMR (300 MHz, CDCl3): l 1.95 (s, 6H, C2ꢂMe),
2.09 (s, 6H, C3ꢂMe), 2.13 (s, 3H, C4ꢂMe), 2.21 (m, 2H,
CH2CH2CH2), 2.44 (s, 3H, MeC6H4), 2.52 (m, 2H,
CH2P), 2.76 (m, 2H, CH2C6Me5), 3.75 (s, 3H, CO2Me),
4.44 (t, 1H, J=5.5 Hz), 4.83 (d, 1H, J=5 Hz), 5.42 (q,
1H, J=5 Hz), 6.14 (d, 1H, J=6 Hz, C6H4CO2Me),
7.40–7.45 (m, 6H), 7.75–7.85 (m, 4H, PPh2). 13C{1H}-
NMR (75.4 MHz, CDCl3): l 16.23 (C2ꢂMe), 16.71
(C3ꢂMe), 16.81 (C4ꢂMe), 19.63 (MeC6H4), 23.19 (d,
2JPC=9 Hz, CH2CH2CH2), 24.13 (d, 1JPC=30 Hz,
CH2P), 31.95 (d, 3JPC=13 Hz, CH2C6Me5), 52.89
The following complexes were prepared likewise.
3.10. [RuCl2(p6-1,2-MeC6H4CO2Me){Ph2P(CH2)3-
C6H5}], brown solid (96% yield)
1H-NMR (300 MHz, CDCl3): l 1.46 (m, 2H,
CH2CH2CH2), 2.41 (m, 2H, CH2P), 2.45 (s, 3H,
MeC6H4), 2.70 (m, 2H, CH2C6H5), 3.77 (s, 3H,
CO2Me), 4.41 (t, 1H, J=5 Hz), 4.77 (d, 1H, J=6 Hz),
(CO2Me), 79.41, 85.64 (d, JPC=9 Hz), 86.01 (d, JPC
=
4
Hz), 89.64, 94.45, 113.85 (d, PC=4 Hz,
J

M.A. Bennett et al. / Journal of Organometallic Chemistry 629 (2001) 7–18
15
C6H4CO2Me), 128.34 (d, JPC=10 Hz), 130.69 (d,
PC=14 Hz, PPh2), 131.64 (C4), 132.40 (C2 or C3),
132.62 (C3 or C2), 132.87 (d, JPC=8 Hz), 133.28 (d,
PC=9 Hz, PPh2), 135.50 (C1), 165.09 (CO2Me).
Me2P), 1.79 (m, 2H, CH2CH2CH2), 2.26 (m, 2H,
CH2C6H5), 2.54 (m, 2H, CH2P), 4.96 (d, 2H, J=5 Hz,
H2), 5.62 (t, 2H, J=6 Hz, H3), 6.33 (t, 1H, J=6 Hz,
H4). 13C{1H}-NMR (75.4 MHz, CDCl3): l 13.22 (d,
1JPC=36 Hz, Me2P), 21.20 (CH2CH2CH2), 24.72 (d,
1JPC=30 Hz, CH2P), 30.08 (CH2C6H5), 80.27 (C2),
89.92 (C1), 92.35 (d, JPC=4 Hz, C3), 98.39 (d, JPC=12
Hz, C4). 31P{1H}-NMR (121.5 MHz, CDCl3): l 13.7.
J
J
31P{1H}-NMR (80.96 MHz, CDCl3): l 27.9. IR (KBr
and polythene, cm−1): 1721 m, 1262 m [w(CO2)] 289 s
[w(RuꢂCl)]. FABMS; m/z: 661 [M−Cl]+. Anal.
Found: C, 59.24; H, 6.00; P, 4.12. Calc. for
C35H41Cl2O2PRu.0.2CH2Cl2: C, 59.24; H, 5.85; P,
4.34%. The presence of CH2Cl2 was evident from the
1H-NMR spectrum.
IR (cm−1
, polythene): 297 s, 278 s [w(RuꢂCl)].
FABMS; m/z: 352 [M+]. Anal. Found: C, 37.25; H,
4.92; P, 8.50. Calc. for C11H17Cl2PRu: C, 37.51; H,
4.86; P, 8.79%.
A similar experiment employing CH2Cl2 (2.5 ml)
containing a drop of THF heated at 120°C for 36 h
gave the complex in 71% yield.
3.13. [RuCl2(p6-1,2-MeC6H4CO2Me)-
{Ph2P(CH2)3-2,4,6-Me3C6H2}], red solid (95% yield)
(ii) A solution of complex 4 (200 mg, 0.31 mmol) in
CH2Cl2 (10 ml) was treated with Me2P(CH2)3C6H5 (119
mg, 0.66 mmol) and stirred for 1 h at r.t.. The mixture
was then heated at 120°C for 48 h in a 35 ml pressure
Schlenk tube and worked up as described above. The
yield of the title compound was 157 mg (72%). The
reaction time could be reduced to 36 h by the addition
of a few drops of THF to the CH2Cl2 solution.
The following complexes were prepared in a similar
way.
1H-NMR (300 MHz, CDCl3): l 2.00 (s, 6H, C2ꢂMe),
2.15 (s, 3H, C4ꢂMe), 2.22 (m, 2H, CH2CH2CH2), 2.41–
2.46 (m, 2H, CH2P), 2.45 (s, 3H, MeC6H4), 2.74 (m,
2H, CH2C6H2Me3), 3.75 (s, 3H, CO2Me), 4.44 (t, 1H,
J=5 Hz), 4.82 (d, 1H, J=6 Hz), 5.42 (q, 1H, J=5
Hz), 6.14 (d, 1H, J=6 Hz, C6H4CO2Me), 6.69 (s, 2H,
H3), 7.40–7.45 (m, 6H), 7.75–7.85 (m, 4H, PPh2).
13C{1H}-NMR (75.4 MHz, CD2Cl2): l 19.52 (C2ꢂMe,
MeC6H4), 20.66 (C4ꢂMe), 22.67 (d, 2JPC=9 Hz,
1
CH2CH2CH2), 24.33 (d, JPC=30 Hz, CH2P), 30.62 (d,
3JPC=13 Hz, CH2C6H2Me3), 52.82 (CO2Me), 79.40,
85.75 (d, JPC=9 Hz), 86.02 (d, JPC=4 Hz), 89.61,
94.44, 113.78 (C6H4CO2Me), 128.35 (d, JPC=10 Hz,
PPh2), 128.66 (C4), 130.59 (C2 or C3), 130.77 (C3 or C2),
3.15. [RuCl2{p1:p6-Ph2P(CH2)3C6H5}] (5)
Compound 5 was obtained by heating [RuCl2(h6-1,2-
MeC6H4CO2Me){Ph2P(CH2)3C6H5}] (840 mg, 1.34
mmol) in CH2Cl2 (20 ml) at 120°C for 72 h. The yield
was 420 mg (66%). Yields of 70–80% could be achieved
using CH2Cl2 containing a few drops of THF and
1
132.85 (d, JPC=8 Hz), 133.19 (d, JPC=8 Hz), 135.16
(d, JPC=43 Hz, PPh2), 135.91 (C1), 165.04 (CO2Me).
31P{1H}-NMR (161.97 MHz, CDCl3): l 27.9. IR (KBr
and polythene, cm−1): 1727 m, 1259 m [w(CO2)] 291 s
[w(RuꢂCl)]. FABMS; m/z: 633 [M−Cl]+. Anal.
Found: C, 59.47; H, 5.97; P, 4.44. Calc. for
C33H37Cl2O2PRu: C, 59.28; H, 5.58; P, 4.63%.
1
heating for 48 h. The H- and 13C{1H}-NMR spectra
are generally in good agreement with those reported
[9,18]. 31P{1H}-NMR (121.5 MHz, CDCl3); l 22.2 (cf.
20.1 [18], −117.08 [9], the latter value presumably
being relative to P(OMe)3). IR (polythene cm−1,): 303
m, 277 m [w(RuꢂCl)]. EIMS; m/z: 476 [M+].
3.14. Preparation of tethered complexes
[RuCl2{p1:p6-Me2P(CH2)3C6H5}] (6)
(i) A solution of [RuCl2(h6-1,2-MeC6H4CO2Me)-
{Me2P(CH2)3C6H5}] (99 mg, 0.20 mmol) in CH2Cl2 (2.5
ml) in a 10 ml pressure Schlenk tube fitted with a
Rotaflo tap was subjected to three freeze–pump–thaw
cycles and then heated at 120°C for 48 h. The solution
was cooled to 0°C and the solvent was removed in
vacuo. The residue was extracted with CH2Cl2, trans-
ferred to a column of neutral alumina (activity III), and
the product was eluted with CH2Cl2 followed by THF.
The eluate was evaporated to dryness in vacuo and the
title compound was isolated as an orange solid (42 mg,
61%) by addition of hexane to a solution in CH2Cl2.
Crystals suitable for X-ray structural analysis were
3.16. [RuCl2{p1:p6-Ph2PCH2SiMe2C6H5}] (7)
Compound 7 was obtained by heating [RuCl2(h6-1,2-
MeC6H4CO2Me){Ph2PCH2SiMe2C6H5}] (675 mg, 1.03
mmol) in CH2Cl2 (17 ml) containing 14 drops of THF
at 120°C for 72 h. The yield of orange solid was 371 mg
(71%). Orange crystals suitable for X-ray crystallogra-
phy were obtained by layering a CH2Cl2 solution with
1
hexane. H-NMR (300 MHz, CDCl3): l 0.33 (s, 6H,
Me2Si), 2.80 (d, 2H, J=15 Hz, CH2P), 5.18 (d, 2H,
J=6 Hz, H2), 5.88 (t, 2H, J=6 Hz, H3), 6.26 (t, 1H,
J=6 Hz, H4), 7.25–7.40 (m, 6H), 7.70–7.75 (m, 4H,
PPh2). 13C{1H}-NMR (75.4 MHz, CDCl3): l −2.77 (d,
4JPC=5 Hz, Me2Si), 29.71 (d, 1JPC=17 Hz, CH2P),
86.30 (C2), 92.13 (d, JPC=2 Hz, C5), 92.68 (d, JPC=6
1
obtained from CH2Cl2–Et2O by vapour diffusion. H-
2
NMR (300 MHz, CDCl3): l 1.54 (d, 6H, JPH=12 Hz,

16
M.A. Bennett et al. / Journal of Organometallic Chemistry 629 (2001) 7–18
Hz, C3), 95.80 (d, JPC=12 Hz, C4), 128.02 (d, JPC=10
Hz), 130.40 (d, JPC=3 Hz), 132.97 (d, JPC=10 Hz),
133.91 (d, JPC=45 Hz, PPh2). 31P{1H}-NMR (121.5
MHz, CDCl3): l 24.0. IR (polythene cm−1,): 303 s, 270
s [w(RuꢂCl)]. FABMS; m/z: 508 [M+]. Anal. Found: C,
50.09; H, 4.55; P, 6.20. Calc. for C21H23Cl2PRuSi: C,
49.80; H, 4.58; P, 6.12%.
Hz), 133.78 (d, JPC=9 Hz, PPh2). 31P{1H}-NMR
(161.97 MHz, CDCl3): l 28.8. IR (polythene cm−1,):
304 s, 288 s [w(RuꢂCl)]. EIMS; m/z: 518 [M+]. Anal.
Found:
C,
57.21;
H,
5.83.
Calc.
for
C24H27Cl2PRu.0.4CH3(CH2)4CH3: C, 57.35; H, 5.94%.
1
The presence of hexane was evident from the H-NMR
spectrum.
The complex was also obtained directly from com-
plex 4 and Ph2PCH2SiMe2C6H5 in a similar yield.
3.19. X-ray crystallography
3.17. [RuCl2{p1:p6-Ph2P(CH2)3C6Me5}] (9)
Details of crystal data, data collection and data
refinement are listed in Table 6. The diffraction data
were collected with graphite-monochromated Cu–Ka
radiation in the case of 6 and with graphite-monochro-
mated Mo–Ka radiation for 7–9 on the following
diffractometers: Rigaku AFC-6R (6), Rigaku AFC-6S
(7), and Nonius Kappa CCD (8, 9). The structures were
solved by direct methods (SIR-92 [31] for 6, 7 and 8, and
DIRDIF-92 [32] for 9), and expanded by use of Fourier
techniques (DIRDIF-94 [33] for 6 and 7, SHELXL-97 [34]
for 8, and (DIRDIF-92 [32] for 9). Refinement was by
full-matrix least-squares on F for 6, 7 and 9, and on F2
for 8. Neutral atom scattering factors for 6 and 7 were
taken from standard compilations [35,36] and for 9
from Ref. [37]. Calculations for 6 and 7 were performed
with TEXSAN [38] for 8 with SHELXL-97 [34], and for 9
with MAXUS [39].
Compound 9 was obtained by heating [RuCl2(h6-1,2-
MeC6H4CO2Me){PPh2(CH2)3C6Me5}] (104 mg, 0.15
mmol) in Bun2 (10 ml) at 140°C for 16 h. The yield of
orange solid was 29 mg (35%). Use of CH2Cl2 contain-
ing a few drops of THF instead of Bun2 gave a yield of
only 7%. X-ray quality crystals were obtained from
1
CH2Cl2–Et2O. H-NMR (400 MHz, CDCl3): l 1.73 (s,
6H, C2ꢂMe), 2.06 (d, 6H, J=0.5 Hz, C3ꢂMe), 2.16 (m,
2H, CH2CH2CH2), 2.22 (d, 3H, J=2.5 Hz, C4ꢂMe),
2.40 (m, 2H, CH2P), 2.56 (t, 2H, J=6 Hz, CH2C6Me5),
7.25–7.30 (m, 6H), 7.60–7.65 (m, 4H, PPh2). 13C{1H}-
NMR (100.6 MHz, CDCl3): l 14.94 (C4ꢂMe), 15.58
(C3ꢂMe), 16.08 (C2ꢂMe), 21.73 (d, 1JPC=31 Hz,
CH2P), 22.67 (CH2CH2CH2), 25.01 (CH2C6Me5), 85.50
(C2), 91.59 (C3), 101.23 (d, JPC=4.5 Hz, C4), 106.29 (d,
J
PC=11 Hz, C1), 127.63 (d, JPC=10 Hz), 129.67,
132.81 (d, JPC=46 Hz), 133.39 (d, JPC=8.5 Hz, PPh2).
31P{1H}-NMR (121.5 MHz, CDCl3): l 26.2. IR (poly-
thene cm−1,): 307 s, 286 s [w(RuꢂCl)]. FABMS; m/z:
546 [M+]. Anal. Found: C, 57.41; H, 5.96; P, 5.66.
Calc. for C26H31Cl2PRu: C, 57.14; H, 5.72; P, 5.67%.
4. Supplementary material
Crystallographic data for the structures reported here
have been deposited with the Cambridge Crystallo-
graphic Data Centre, the CCDC deposition numbers
being 155393, 155392, 152318 and 155322 for com-
pounds 6, 7, 8 and 9, respectively. Copies of this
information may be obtained free of charge from: The
Director, CCDC, 12 Union Road, Cambridge, CB2
1EZ, UK (Fax: +44-1223-336-033; e-mail: de-
posit@ccdc.cam.ac.uk or www:http://www.ccdc.cam.
ac.uk
3.18. [RuCl2{p1:p6-Ph2P(CH2)3-2,4,6-C6H2Me3}] (8)
Compound 8 was obtained by heating [RuCl2(h6-1,2-
MeC6H4CO2Me){PPh2(CH2)3-2,4,6-C6H2Me3}]
(170
mg, 0.23 mmol) in CH2Cl2 (3 ml) at 120°C for 24 h. In
the work-up, the chromatographic eluate was evapo-
rated to dryness and re-chromatographed. The eluate
was evaporated to dryness, redissolved in CH2Cl2 and
treated with hexane. Evaporation to dryness gave a
gummy residue, which on trituration with hexane, af-
forded the title compound as an orange solid (24 mg,
18%). X-ray quality crystals were obtained by layering
Acknowledgements
The authors wish to thank the Crystallographic Ser-
vice at Monash University for collecting the data for
complex 9, Mr Horst Neumann (ANU) for the prepa-
ration of chlorodimethylphosphine, Dr Richard Web-
ster (ANU) for assistance with some of the
electrochemical measurements, Professor Brian John-
son (University of Cambridge) for helpful discussions,
and the EPSRC for financial support of the purchase of
the Nonius Kappa CCD at the University of
Cambridge.
1
a CH2Cl2 solution with hexane. H-NMR (400 MHz,
CDCl3): l 1.36 (s, 6H, C2ꢂMe), 1.79 (s, 6H, C4ꢂMe),
2.16 (m, 2H, CH2CH2CH2), 2.39 (m, 4H, CH2P,
CH2C6H2Me3), 5.25 (s, 2H, H3), 7.20–7.25 (m, 6H),
7.50–7.55 (m, 4H, PPh2). 13C {1H}-NMR (100.6 MHz,
CDCl3): l 11.39 (C4ꢂMe), 18.73 (C2ꢂMe), 20.54 (d,
1JPC=26 Hz, CH2P), 25.26 (CH2CH2CH2), 34.64
(CH2C6H2Me3), 84.81 (C2), 92.34 (C3), 96.30 (C4),
127.65 (d, JPC=10 Hz), 129.90, 132.73 (d, JPC=48

M.A. Bennett et al. / Journal of Organometallic Chemistry 629 (2001) 7–18
17
Table 6
Crystal and structure refinement data for complexes 6–9
Complex
6
7
8
9
Empirical formula
Formula weight
Temperature (K)
C11H17Cl2PRu
352.21
296(1)
C
506.45
296(1)
21H23Cl2PRuSi
C24H27Cl2PRu·CH2Cl2 C26H31Cl2PRu
603.32
546.48
180(2)
200(2)
,
Wavelength (A)
1.54178
Monoclinic
P21/c (No. 14)
0.71069
Monoclinic
P21/n (No. 14)
0.71070
Triclinic
0.71073
Monoclinic
C2/c
Crystal system
Space group
(
P1
Unit cell dimensions
,
a (A)
13.649(1)
13.453(1)
14.479(1)
11.124(3)
13.114(2)
14.965(2)
8.1450(5)
9.0570(5)
18.7720(6)
101.286(3)
91.615(3)
113.800(2)
1233.64(11)
2
29.4890(4)
8.4700(1)
22.7143(4)
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
V (A )
102.892(7)
95.85(2)
125.4491(6)
3
,
2591.8(4)
8
1.805
2171.8(7)
4
1.549
4621.72(12)
8
1.571
2903
9.9 (Mo)
0.10×0.03×0.03
Orange, needle
2.91–26.37
16326
4879 [Rint=0.065]
3487 [I\3|(I)]
Empirical [40,41]
Z
Dcalc(g cm−3
F(000)
)
1.624
612
1408
1024
v(M–Ka) (cm−1
)
148.50 (Cu)
0.14×0.14×0.07
Orange, block
2–60
10.86 (Mo)
0.37×0.20×0.08
Orange, plate
2–60
11.46 (Mo)
0.16×0.14×0.05
Orange, block
3.71–25.05
6616
4248 [Rint=0.054]
3529 [I\2|(I)]
None
Crystal size (mm)
Crystal colour, habit
q Range for data collection (°)
Number of reflections
Unique
4226
6541
4049 [Rint=0.049]
2589 [I\2|(I)]
Analytical
0.15–0.41
272
R1=0.042,
wR2=0.056
1.81
5247 [Rint=0.015]
3892 [I\2|(I)]
Analytical
0.81–0.92
236
R1=0.025,
wR2=0.023
1.48
Observed
Absorption correction
Transmission factors
Number of parameters
Final R indices
283
272
R1=0.041,
wR2=0.093
1.03a
R1=0.032,
wR2=0.072
2.38
Goodness-of-fit on F
Largest difference peak and hole (e A
−3
,
)
1.35 and −1.14
0.45 and −0.45
0.594 and −0.855
0.54 and −0.64
a Goodness-of-fit on F2.
[15] B. Therrien, A. Ko¨nig, T.R. Ward, Organometallics 18 (1999)
1565.
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