The synthesis, structure and selected reactivity of a series of tricarbonyl ruthenium complexes with 1,3-dienes and heterodienes

Article abstract of DOI:10.1016/S0022-328X(98)00950-4

Displacement of the weakly ligated ethylene ligands in the complex Ru(CO)₃{η²-C₂H₄}₂ has been used to synthesise a series of tricarbonyl ruthenium compounds of η⁴-coordinated 1,3-dienes and 1,3-heterodienes. Complexes of η⁴-coordinated 1,3-heterodienes could not be isolated due to their extreme reactivity. Selected reactions were performed to replace a carbonyl at the metal centre with a phosphite, or to modify the coordinated ligand by standard methodologies. Single crystal X-ray analyses have been performed on the complexes [Ru(CO)₃{(E,E)-1,4-diphenylbuta-1,3-diene}], [Ru(CO)₃{ethyl(E,E)-5-phenylpenta-2,4-dien-1-oate}], [Ru(CO)₃{(E,E)-5-phenylpenta-2,4-dienal}] and [Ru(CO)₃{(E,E)-5-phenylpenta-2,4-dienol}] and indicate a change in electronic environment within the diene moiety on coordination.

Full text of DOI:10.1016/S0022-328X(98)00950-4

Journal of Organometallic Chemistry 574 (1999) 302–310
The synthesis, structure and selected reactivity of a series of
tricarbonyl ruthenium complexes with 1,3-dienes and heterodienes
Scott L. Ingham *, Steven W. Magennis
Department of Chemistry, The Uni6ersity of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK
Received 8 June 1998
Abstract
Displacement of the weakly ligated ethylene ligands in the complex Ru(CO)3{p2-C2H4}2 has been used to synthesise a series of
tricarbonyl ruthenium compounds of p4-coordinated 1,3-dienes and 1,3-heterodienes. Complexes of p4-coordinated 1,3-heterodi-
enes could not be isolated due to their extreme reactivity. Selected reactions were performed to replace a carbonyl at the metal
centre with a phosphite, or to modify the coordinated ligand by standard methodologies. Single crystal X-ray analyses have been
performed on the complexes [Ru(CO)3{(E,E)-1,4-diphenylbuta-1,3-diene}], [Ru(CO)3{ethyl(E,E)-5-phenylpenta-2,4-dien-1-oate}],
[Ru(CO)3{(E,E)-5-phenylpenta-2,4-dienal}] and [Ru(CO)3{(E,E)-5-phenylpenta-2,4-dienol}] and indicate a change in electronic
environment within the diene moiety on coordination. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Ruthenium; Tricarbonyl; Dienes; Heterodienes
analogues. These vigorous conditions commonly give
rise to the formation of products containing metal–
metal bonds [15], or those in which C–H bond activa-
tion has occurred [16] and subsequently the desired
mononuclear compounds are produced in low yields or
not at all [17]. The use of pre-formed mononuclear
species with readily displaceable ligands, such as
Ru(CO)3{p4-cycloocta-1,5-diene} [18,19] or Ru(CO)4
{p2-methyl acrylate} [20] have been used to avoid many
of the synthetic problems mentioned above. A more
attractive synthetic intermediate is the bis(ethylene)
complex Ru(CO)3{p2-C2H4}2, which can be quantita-
tively generated in situ by photolysis of an ethylene
saturated hydrocarbon solution of Ru3(CO)12 [21]. This
complex has the distinct advantage that it need not be
isolated. In addition, any excess ethylene may be read-
ily purged from the reaction mixture. In this paper we
report the synthesis, structure and reactivity of a series
of tricarbonyl{p4-1,3-diene} ruthenium complexes gen-
erated via the displacement of the labile ethylene lig-
ands in Ru(CO)3{p2-C2H4}2.
1. Introduction
Tricarbonyl(p4-1,3-diene) iron complexes have been
widely utilised as intermediates for organic synthesis
[1–3]. The bulky tricarbonyliron moiety is an effective
stereo-directing group and can function as a chiral
auxilliary when complexed to prochiral dienes [4–10].
In comparison, the analogous ruthenium complexes are
not so readily available and as such have received
relatively little attention to date [11–14]. This may
reflect the lack of an easily accessible and high yielding
synthetic strategy. Generally these compounds have
been synthesised by the photolysis or thermolysis of
Ru3(CO)12 in the presence of an excess of the diene and
usually require more forcing conditions than their iron
* Corresponding author. Present address: Alcan Chemicals Europe,
Burntisland, Fife, Scotland KY3 0EP, UK. Fax: +44-1592-411-111;
E-mail: scott ingham@alcan.com.
–
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(98)00950-4

S.L. Ingham, S.W. Magennis / Journal of Organometallic Chemistry 574 (1999) 302–310
303
2. Results and discussion
found that 8 may be synthesised from Ru(CO)3{p2-
C2H4}2, it readily decomposes to the known di-ruthe-
nium complex (v2-H)Ru2(CO)6{m2-C10H9O}, obtained
by C–H bond activation of the bound olefin (Scheme
1) [16]. Due to the lack of stability of 8 it was character-
ised solely by comparison of its IR spectrum to that
reported for the related iron compound [Fe(CO)3{(E)-
4-phenyl-3-buten-2-one}] [19]. The synthesis of com-
plexes 1–8 from Ru(CO)3{p2-C2H4}2 is summarised in
Scheme 2.
Replacement of a carbonyl group in 3 with a phos-
phite ligand is readily achieved by the addition of 1.3
equivalents of trimethylamine-N-oxide to a dichlorome-
thane solution of 3 containing an excess of P(OCH3)3.
After purification by column chromatography, a pale
yellow crystalline material was obtained in moderate
yield, which was formulated as [Ru(CO)2P(OCH3)3{(E,
E)-1,4-diphenylbuta-1,3-diene}] (9) on the basis of spec-
troscopic data (Scheme 3). The replacement of a car-
bonyl ligand with the weaker y-acceptor phosphite
results in a greater degree of back-donation into the y*
orbitals of the two remaining carbonyl groups. This is
exemplified by a shift in the observed IR frequency of
the CꢀO groups to lower wavenumbers for 9 and
demonstrates that the replacement of a carbonyl with a
suitable phosphine or phosphite allows the electronic
and steric properties of these molecules to be subtly
modified.
From the reaction of a pentane solution of photo-
chemically generated Ru(CO)3{p2-C2H4}2 with an ex-
cess of cyclohexa-1,3-diene, was isolated the known
compound Ru(CO)3{p4-cyclohexa-1,3-diene}(1) [22] in
high yield. The formation of products containing more
than one ruthenium atom was not observed, which is in
contrast to the reported synthesis of 1 by the thermoly-
sis of Ru3(CO)12 [22]. It was also observed that the
isomerisation of cyclohexa-1,4-diene occurs on reaction
with Ru(CO)3{p2-C2H4}2 at ambient temperature to
give the complex 1. This observation is in accord with
that reported for the reaction between Ru(CO)3{p4-cy-
cloocta-1,5-diene} and cyclohexa-1,4-diene [18]. Reac-
tion between Ru(CO)3{p2-C2H4}2 and (E,E)-hexa-2,
4-dienal yielded [Ru(CO)3{(E,E)-hexa-2,4-dienal}] (2)
in a reasonable yield as a moderately air-sensitive pale
yellow oil. Although the latter compound has been
reported in the literature [23], to our knowledge no
synthetic or spectroscopic data have been published. As
expected, 1 and 2 are significantly more sensitive to
oxidation upon exposure to the atmosphere than their
iron analogues. We reasoned that the replacement of
the alkyl group on the diene moiety with an aromatic
substituent would result in complexes that would be less
susceptible to oxidation due to enhanced electronic
delocalisation. Indeed, reaction between Ru(CO)3{p2-
C2H4}2 and (E,E)-1,4-diphenylbuta-1,3-diene gave the
Reduction of the ester functionality of 5 was readily
achieved by reaction of a THF solution of 5 with 2.2
equivalents of diisobutylaluminium hydride. Purifica-
tion by preparative thin layer chromatography yielded
a white crystalline material in good yield, that on the
basis of spectroscopic and analytical data was formu-
lated as [Ru(CO)3{(E,E)-5-phenyl-2,4-pentadienol}]
(10) (Scheme 4).
air-stable
pale
yellow
crystalline
material
[Ru(CO)3{(E,E)-1,4-diphenylbuta-1,3-diene}] (3) in
good yield. This compound has previously been iso-
lated, together with a series of di- and tri-ruthenium
species, from the thermolysis of Ru3(CO)12 and (E,E)-
1,4-diphenylbuta-1,3-diene [11]. The complexes [Ru-
(CO)3{methyl
(E,E)-5-phenylpenta-2,4-dien-1-oate}]
(4), [Ru(CO)3{ethyl (E,E)-5-phenylpenta-2,4-dien-1-
oate}] (5) and [Ru(CO)3{(E,E)-5-phenylpenta-2,4-di-
enal}] (6) were also isolated in good yields as air stable
crystalline materials from the reactions between
Ru(CO)3{p2-C2H4}2 and the appropriate ligands. In
contrast, the heterodienes (E,E)-1,4-diphenyl-1-az-
abuta-1,3-diene and (E)-4-phenyl-3-buten-2-one reacted
with Ru(CO)3{p2-C2H4}2 to form the complexes
[Ru(CO)3{(E,E)-1,4-diphenyl-1-azabuta-1,3-diene}] (7)
and [Ru(CO)3{(E)-4-phenyl-3-buten-2-one}] (8), respec-
tively but could not be isolated due to their instability.
Compound 7 was characterised on the basis of its
1H-NMR and IR spectra and the comparison of these
with the related compounds [Ru(CO)2L{(E,E)-1-
phenyl-4-tolyl-1-azabuta-1,3-diene}] (L=CO, PPh3)
and [Fe(CO)3{(E,E)-1,4-diphenyl-1-azabuta-1,3-diene}]
[24,25]. It is noteworthy that von Philipsborn et al.
reported that all attempts to synthesise 8 by the replace-
ment of ethylene in Ru(CO)4{p2-C2H4} by the heterodi-
ene and subsequent decarbonylation failed. Whilst we
Complexation of the Ru(CO)3 moiety with prochiral
dienes produces a racemic mixture and the use of these
complexes in asymmetric synthesis demands efficient
resolution of their enantiomers [2,26]. Racemic mix-
tures of Fe(CO)3{p4-diene} complexes have previously
been resolved by the fractional crystallisation of oxazo-
lidines, formed on reaction with (–)-(1R,2S)-ephedrine
[27]. Attempts were made to separate a racemic mixture
of 6 by this method. Although formation of diastereo-
mers was observed by 1H-NMR, separation by
Scheme 1.

304
S.L. Ingham, S.W. Magennis / Journal of Organometallic Chemistry 574 (1999) 302–310
Scheme 2.
fractional crystallisation or thin layer chromatography
proved unsuccessful. The development of suitable
preparative methods for enantiopure complexes will be
the focus of further work.
comitant decrease in the ‘inner’ carbon–carbon bond
length on coordination from 1.437(5) to 1.408(4) A. It
˚
is of some note that there is no significant change on
coordination for the bond lengths between the diene
moiety and the phenyl substituents. The variation of
the diene bond lengths on coordination can be traced to
the partial population of the Lowest Unoccupied
Molecular Orbital (LUMO) of the diene in the coordi-
nated ligand [31]. This orbital is antibonding with re-
spect to the ‘outer’ carbon–carbon bonds, but bonding
with respect to the ‘inner’ bond. The most notable
change in the overall configuration of the ligand upon
coordination is the expected transformation from the
transoid to the cisoid conformation. Whilst relatively
uncommon, there are examples of ruthenium(II) com-
plexes with dienes coordinated in the transoid form
[32,33], whereas only the cisoid conformation is known
for ruthenium(0) complexes. The diene carbon atoms
C(07), C(08), C(09) and C(010) lie in a plane, but
overall there is a considerable distortion from planarity
of the coordinated ligand, with the diene plane making
angles of 21.2(1) and 25.9(1)°, respectively to the phenyl
rings C(01)–C(06) and C(011)–C(016). In contrast to
the ‘inner’ diene hydrogen atoms H(08) and H(09),
Single crystal X-ray structure determinations were
performed on compounds 3, 5, 6 and 10. Complex 3
can be obtained in two distinct crystal forms. The first
form has half an equivalent of the uncoordinated ligand
present in the crystal lattice, whereas the second form
does not [28]. The structure of 3 described is for the
first form, with both found to be isomorphous to their
respective iron analogues [29,30]. The molecular struc-
ture of 3 is depicted in Fig. 1, with selected bond
lengths presented in Table 1. The ruthenium tricarbonyl
moiety coordinates to the diene in the expected p4
fashion, with the ‘outer’ carbon atoms approximately
˚
0.06 A further from the metal centre than the ‘inner’
carbon atoms. The presence of the uncoordinated lig-
and in the crystal lattice allows a direct comparison of
bond lengths within the diene functionality upon coor-
dination. The ‘outer’ bonds C(07)–C(08) and C(09)–
˚
C(010) are 1.433(4) and 1.432(4) A, respectively and
these are significantly longer than the analogous bonds
˚
in the uncoordinated ligand (1.310(4) A). In addition to
the lengthening of these ‘outer’ bonds, there is a con-
Scheme 4.
Scheme 3.

S.L. Ingham, S.W. Magennis / Journal of Organometallic Chemistry 574 (1999) 302–310
305
Fig. 1. Molecular structure of [Ru(CO)3{(E,E)-1,4-diphenylbuta-1,3-diene}] 3.
which do not deviate significantly from the diene plane,
the ‘outer’ hydrogen atoms H(07) and H(010) both lie
above this plane by 0.50(3) A, . This displacement of the
asymmetry in bond lengths is also noted within the
diene moiety, with ‘outer’ diene bond distances of
1.439(4) and 1.417(4) A being observed for C(04)–C(05)
˚
and C(06)–C(07), respectively in 5. Whilst these varia-
tions in bond length are relatively small and close to the
level of statistical significance, a similar observation is
made for 6, with the ‘outer’ diene bonds C(02)–C(03)
and C(04)–C(05) being of length 1.445(3) and 1.425(3)
‘outer’ diene protons from the plane of the diene carbon
atoms, increases the overlap of metal- and ligand-based
orbitals and also stabilises the ligand LUMO [34]. The
molecular structure of 3 is markedly similar to the
previously reported iron analogue [29], with the only
significant variation in bond lengths observed for the
˚
A, respectively. Electronic delocalisation between the
˚
carbonyl substituent and the diene results in a stabilisa-
tion of the ligand LUMO and therefore an increase in
the partial population of this orbital, which as described
above is antibonding with respect to the ‘outer’ diene
bonds and bonding with respect to the ‘inner’ diene
bond. The molecular structure of 10 is depicted in Fig.
4, with selected bond lengths presented in Table 4.
Structurally, 10 is similar to 5 and 6, with asymmetric
‘outer’ ruthenium–carbon bonds. The lower degree of
accuracy for the crystal structure determination of 10,
relative to the determinations performed for 3, 5 and 6,
precludes a detailed comparison of bond parameters
within the coordinated diene fragments.
In conclusion we have shown that tricarbonyl ruthe-
nium complexes of p4-coordinated 1,3-dienes and 1,3-
heterodienes may be readily synthesised via the reactive
compound Ru(CO)3{p2-C2H4}2. Tricarbonyl ruthenium
complexes of p4-coordinated 1,3-heterodienes could not
be isolated due to their extreme reactivity, but were
characterised by IR spectroscopy. Complexes contain-
ing coordinated alkyl substituted 1,3-dienes were found
to be moderately sensitive to air, whilst those with
aromatic substituents were isolated as air stable solids.
Selected reactions were performed that indicated it was
possible to replace a carbonyl at the metal centre, or to
modify the coordinated ligand by standard methodolo-
gies. Present studies are focused on the development of
efficient synthetic strategies for the preparation of enan-
tiopure complexes. Single crystal structural analyses
indicate that the p4-coordination of 1,3-dienes by the
ruthenium tricarbonyl group gives complexes with simi-
metal–carbon distances, which are approximately 0.1 A
shorter in the iron derivative as might be expected.
The molecular structures of 5 and 6 are depicted in
Figs. 2 and 3, with selected bond lengths presented in
Tables 2 and 3, respectively. The metal centre in 5 and
6 coordinates to the respective diene ligands in a p4
manner as was observed for 3. There are however some
small differences in the bond lengths between the metal
and the diene carbon atoms and within the diene
moiety, with these differences likely to be attributable to
the asymmetric nature of the ligands. The ruthenium
centre appears to make a stronger interaction with the
double bond attached to the carbonyl substituent in
˚
both 5 and 6. For example the metal is 2.217(3) A away
from the ‘outer’ carbon C(04) that is adjacent to the
ester substituent in 5. In comparison the ruthenium–
carbon bond length for the ‘outer’ carbon adjacent to
˚
the aromatic substituent {Ru–C(07), 2.261(3) A} is
˚
0.044(6) A longer. A similar observation is made for 6
where the ‘outer’ ruthenium–carbon distances are
˚
2.270(2) and 2.222(2) A, the latter being the bond length
for the carbon adjacent to the aldehyde substituent. This
Table 1
˚
Selected bond lengths (A) for complex 3
Ru–C(07)
Ru–C(08)
Ru–C(09)
Ru–C(010)
C(06)–C(07)
2.250(2)
2.196(2)
2.202(2)
2.262(2)
1.484(3)
C(07)–C(08)
C(08)–C(09)
C(09)–C(010)
C(010)–C(011)
1.433(4)
1.408(4)
1.432(4)
1.481(3)

306
S.L. Ingham, S.W. Magennis / Journal of Organometallic Chemistry 574 (1999) 302–310
Fig. 2. Molecular structure of [Ru(CO)3{ethyl (E,E)-5-phenylpenta-2,4-dien-1-oate}] 5.
lar structural parameters to their iron analogues and
the bonding within these molecules may be largely
described in terms of back donation from the metal
into a ligand based LUMO [33].
pared from Ru3(CO)12 (0.256 g, 0.40 mmol) in pen-
tane (150 cm−3) was added an excess (1 cm−3) of
cyclohexa-1,3-diene and the solution purged with dini-
trogen for ca. 30 min. The resulting pale yellow solu-
tion was stirred at room temperature (r.t.) overnight
and then filtered through a pad of silica. Removal of
the solvent and unreacted cyclohexa-1,3-diene at re-
duced pressure yielded 0.248 g (78%) of a pale yellow
oil, identified as the desired compound on the basis
of previously reported spectroscopic evidence [40].
w˜max cm−1 (pentane) 2062s, 1994vs and 1989vs (CO).
3. Experimental
All reactions were performed under an atmosphere
of purified dinitrogen by standard Schlenk and vac-
uum line techniques [35]. Subsequent work-up of
products was carried out without precautions to ex-
clude air. Solvents used were distilled from appropri-
ate drying agents under dinitrogen [36]. Routine
separations of products were performed by column
chromatography using Merck Kieselgel 60 (230–400
mesh) and thin layer chromotography using commer-
cially available glass plates, precoated to 0.25 mm
thickness with Merck Kieselgel 60 PF254. IR spectra
were recorded as pentane solutions on a Perkin-Elmer
1710 Fourier Transform spectrometer. 1H-, 13C{1H}-
3.2. [Ru(CO)3{(E,E)-hexa-2,4-dienal}] (2)
The synthesis of this compound has appeared in
the literature [23], however no spectroscopic data
were reported. A synthesis analogous to that used for
1 was employed. Purification was performed by filtra-
tion through celite to yield 54% of the desired
product as a moderately air-sensitive pale yellow oil.
w˜max cm−1 (pentane) 2078s, 2018vs and 2002vs (CO);
lH(CDCl3) 9.19 (1 H, d, J=4.1 Hz, CHO), 5.77 (1
H, dd, J=5.2, 6.9 Hz, CHꢁCH–CHO), 5.36 (1 H,
dd, J=5.0, 8.1 Hz, CHꢁCH–CH3), 1.80–1.93 (1 H,
m, CH–CH3), 1.74 (1 H, dd, J=4.2, 7.1 Hz, CH–
CHO), 1.54 (3 H, d, J=6.0 Hz, CH3); lC(CDCl3)
195.3 (1 C, CHO), 92.3 (1 C, CHꢁCH–CH3), 81.3 (1
C, CHꢁCH–CHO), 52.6 (1 C, CH–CH3), 52.3 (1 C,
CH–CHO), 19.8 (3 C, CH3); m/z 282 [MH]+.
C9H8O4Ru requires M (based on 101Ru) 281.
and 31P{1H}-NMR spectra were recorded on
a
Bruker AC-250 spectrometer and were referenced to
external TMS (1H and 13C{1H}) or 85% H3PO4
(31P{1H}). 13CO resonances for complexes 2 and 6
were not observed. Positive ion fast atom bombard-
ment mass spectra were recorded on a Kratos MS-50
mass spectrometer, using m-nitrobenzyl alcohol as a
matrix. Elemental analyses were performed in this de-
partment by standard techniques. The compound
[Ru(CO)3{C2H4}2] was generated in situ by the pho-
tolysis of Ru3(CO)12 as previously described [37]. The
ligands methyl (E,E)-5-phenylpenta-2,4-dien-1-oate,
ethyl (E,E)-5-phenylpenta-2,4-dien-1-oate and (E,E)-5-
phenylpenta-2,4-dienal were synthesised according to
literature preparations [38,39].
3.3. [Ru(CO)3{(E,E)-1,4-diphenylbuta-1,3-diene}] (3)
The synthesis of this compound has appeared in
the literature [11], however no 13C{1H}-NMR data
was reported. A synthesis analogous to that used for
1 was employed. The crude product readily crys-
1
3.1. [Ru(CO)3{cyclohexa-1,3-diene}] (1)
tallises, with this material shown by H-NMR to con-
tain 0.5 equivalents of the uncoordinated ligand.
Purification was performed by column chromatogra-
To a colourless solution of [Ru(CO)3{C2H4}2] pre-

S.L. Ingham, S.W. Magennis / Journal of Organometallic Chemistry 574 (1999) 302–310
307
Fig. 3. Molecular structure of [Ru(CO)3{(E,E)-5-phenylpenta-2,4-dienal}] 6.
phy eluting with a 10% dichloromethane–hexane mix-
3.5. [Ru(CO)3{ethyl
ture to afford the desired product as an air stable
pale yellow crystalline material (Rf=0.36, 42.6%).
w˜max cm−1 (pentane) 2078s, 2018vs and 2002vs (CO);
lC(CDCl3) 225.9 (3 C, CO), 141.3 (2 C, ipso-Ar),
128.5 (4 C, o-Ar), 125.7 (2 C, p-Ar), 125.5 (4 C,
m-Ar), 82.5 (2 C, CHꢁCH–CHꢁCH), 54.3 (2 C,
CHꢁCH–CHꢁCH).
(E,E)-5-phenylpenta-2,4-dien-1-oate}] (5)
A synthesis analogous to that used for 1 was em-
ployed. Purification was performed by column chro-
matography eluting with dichloromethane to afford a
pale yellow air stable crystalline material. (Rf=0.71,
56.3%) [Found: C, 49.6; H 3.5; m/z 387. C16H14O5Ru
requires C, 49.61; H, 3.64%; M (based on 101Ru)
387], w˜max cm−1 (pentane) 2077s, 2017vs, 2007s (CO);
lH(CDCl3) 7.10–7.28 (5 H, m, Ar), 5.94–6.01 (2 H,
m, CHꢁCH–CHꢁCH), 4.06–4.19 (2 H, m, CH2),
2.63–2.69 (1 H, m, Ar–CH), 1.66–1.72 (1 H, m,
CH–CO2CH2CH3), 1.26 (3 H, t, J=7.1 Hz, CH3);
lC(CDCl3) 199.0 (1 C, CO), 194.5 (1 C, CO), 193.3 (1
C, CO), 172.7 (1 C, CO2CH2CH3), 140.6 (1 C, ipso-
Ar), 128.7 (2 C, o-Ar), 126.1 (1 C, p-Ar), 125.6 (2 C,
m-Ar), 85.9 (1 C, Ar–CHꢁCH), 84.3 (1 C, CHꢁCH–
CO2CH2CH3), 60.3 (1 C, CH2), 55.9 (1 C, Ar–CH),
42.1 (1 C, CH–CO2CH2CH3), 14.2 (1 C, CH3).
3.4. [Ru(CO)3{methyl
(E,E)-5-phenylpenta-2,4-dien-1-oate}] (4)
A synthesis analogous to that used for 1 was em-
ployed. Purification was performed by column chro-
matography eluting with dichloromethane to afford a
pale yellow air stable crystalline material. (Rf=0.67,
61.8%) [Found: C, 48.2; H 3.2; m/z 373. C15H12O5Ru
requires C, 48.26; H, 3.24%; M (based on 101Ru)
373], w˜max cm−1 (pentane) 2078s, 2017vs, 2007s (CO);
lH(CDCl3) 7.09–7.28 (5 H, m, Ar), 5.94–6.01 (2 H,
m, CHꢁCH–CHꢁCH), 3.67 (3 H, s, CH3), 2.64–2.69
(1 H, m, Ar–CH), 1.66–1.72 (1 H, m, CH–
CO2CH3); lC(CDCl3) 198.9 (1 C, CO), 194.4 (1 C,
CO), 193.3 (1 C, CO), 173.2 (1 C, CO2CH3), 140.5 (1
C, ipso-Ar), 128.7 (2 C, o-Ar), 126.2 (1 C, p-Ar),
125.5 (2 C, m-Ar), 86.0 (1 C, Ar–CHꢁCH), 84.2 (1
C, CHꢁCH–CO2CH3), 56.0 (1 C, Ar–CH), 51.5 (1
C, CH3), 41.5 (1 C, CH–CO2CH3).
3.6. [Ru(CO)3{(E,E)-5-phenylpenta-2,4-dienal}] (6)
A synthesis analogous to that used for 1 was em-
ployed. Purification was performed by column chro-
matography eluting with dichloromethane to afford a
pale yellow air stable crystalline material. (Rf=0.47;
50.5%) [Found: C, 49.1; H 2.9; m/z 344 [MH]+.
Table 2
Table 3
˚
˚
Selected bond lengths (A) for complex 5
Selected bond lengths (A) for complex 6
Ru–C(04)
Ru–C(05)
Ru–C(06)
Ru–C(07)
C(03)–C(04)
2.217(3)
2.176(3)
2.203(3)
2.261(3)
1.473(4)
C(04)–C(05)
C(05)–C(06)
C(06)–C(07)
C(07)–C(08)
1.439(4)
1.408(4)
1.417(4)
1.486(4)
Ru–C(02)
Ru–C(03)
Ru–C(04)
Ru–C(05)
C(01)–C(02)
2.222(2)
2.175(2)
2.209(2)
2.270(2)
1.458(3)
C(02)–C(03)
C(03)–C(04)
C(04)–C(05)
C(05)–C(06)
1.445(3)
1.411(3)
1.425(3)
1.485(2)

308
S.L. Ingham, S.W. Magennis / Journal of Organometallic Chemistry 574 (1999) 302–310
Fig. 4. Molecular structure of [Ru(CO)3{(E,E)-5-phenylpenta-2,4-dienol}] 10.
C14H10O4Ru requires C, 48.98; H, 2.94%; M (based on
101Ru) 343], w˜max cm−1 (pentane) 2080s, 2021vs, 2010s
(CO); lH(CDCl3) 9.34 (1 H, d, J=3.8 Hz, CHO),
7.12–7.38 (5 H, m, Ar), 5.95–6.08 (2 H, m, CHꢁCH–
CHꢁCH), 2.92 (1 H, d, J=8.5 Hz, Ar–CH), 2.06 (1
H, dd, J=7.2, 3.8 Hz, CH–CHO); lC(CDCl3) 195.1 (1
C, CHO), 139.8 (1 C, ipso-Ar), 128.7 (2 C, o-Ar), 126.4
(1 C, p-Ar), 125.5 (2 C, m-Ar), 87.1 (1 C, Ar–
CHꢁCH), 81.7 (1 C, CHꢁCH–CHO), 56.8 (1 C, Ar–
CH), 52.3 (1 C, CH–CHO).
cm−1 (pentane) 2073s, 2012vs, 2000s (CO); lH(CDCl3)
7.12–7.44 (10 H, m, Ar), 7.00 (1 H, dd, J=3.2, 1.0
Hz, CHꢁN), 5.53 (1 H, dd, J=8.4, 3.1 Hz, CHꢁCH–
CH), 3.62 (1 H, dd, J=8.4, 1.0 Hz, Ph–CH).
3.8. [Ru(CO)3{(E)-4-phenyl-3-buten-2-one}] (8)
A synthesis analogous to that used for 1 was em-
ployed. This compound readily decomposes at ambient
temperatures and therefore was characterised solely by
comparison of its IR spectrum to that reported for the
related iron(0) compound [Fe(CO)3{(E)-4-phenyl-3-
buten-2-one}] [19]. w˜max cm−1 (pentane) 2068s, 2008vs,
1988s (CO).
3.7. [Ru(CO)3{(E,E)-1,4-diphenyl-1-azabuta-1,3-diene}]
(7)
A synthesis analogous to that used for 1 was em-
ployed. Attempts to isolate this compound in a pure
form were not successful due to its lack of stability and
therefore this compound was characterised by compari-
3.9. [Ru(CO)2P(OCH3)3{(E,E)-1,4-diphenylbuta-
1,3-diene}] (9)
1
son of its H-NMR and IR spectra to that reported for
To a solution of 3 (0.100 g, 0.256 mmol) in
dichloromethane (50 cm−3) at r.t. was added in succes-
sion an excess of P(OCH3)3 (0.2 cm−3) and (CH3)3NO
(0.250 g, 0.333 mmol). The resulting solution was
stirred for 4 h, at which point complete consumption
of 3 was indicated by IR spectroscopy. Removal of
solvent and excess P(OCH3)3, followed by column
chromatography eluting with a 25% dichloromethane–
hexane mixture afforded the desired product as a pale
yellow micro-crystalline material (Rf=0.25, 0.047 g,
37.6%). m/z 488 [MH]+; C21H23O5PRu requires M
(based on 101Ru) 487, w˜max cm−1 (pentane) 2010vs,
1952s (CO); lH(CDCl3) 6.99–7.43 (10 H, m, Ar), 5.85–
the related compounds [Ru(CO)3{(E,E)-1-phenyl-4-
tolyl-1-azabuta-1,3-diene}], [Ru(CO)2(PPh3)2{(E,E)-1-
phenyl-4-tolyl-1-azabuta-1,3-diene}] and [Fe(CO)3-
{(E,E)-1,4-diphenyl-1-azabuta-1,3-diene}] [24,25] w˜max
Table 4
˚
Selected bond lengths (A) for complex 10
Ru–C(02)
Ru–C(03)
Ru–C(04)
Ru–C(05)
C(01)–C(02)
2.211(9)
2.195(8)
2.204(8)
2.257(8)
1.509(12)
C(02)–C(03)
C(03)–C(04)
C(04)–C(05)
C(05)–C(06)
1.409(13)
1.417(11)
1.423(11)
1.490(12)
5.92 (2 H, m, CHꢁCH–CHꢁCH), 3.34 (9 H, d, JPH
12.4 Hz, CH3), 2.00–2.06 (2 H, m, CHꢁCH–CHꢁCH);
=

S.L. Ingham, S.W. Magennis / Journal of Organometallic Chemistry 574 (1999) 302–310
309
Table 5
Summary of crystallographic data for complexes 3, 5, 6 and 10a
3
5
6
10
Empirical formula
Formula weight
Crystal size (mm)
Crystal class
C27H21O3Ru
494.51
0.47, 0.31, 0.19
Triclinic
P1
9.311(2)
10.178(2)
12.415(3)
75.75(2)
89.49(2)
71.81(1)
1080.4(4)
2
C16H14O5Ru
387.34
0.42, 0.35, 0.20
Monoclinic
P21/n
7.3735(9)
10.044(1)
21.617(3)
90
98.60(1)
90
1582.9(4)
4
C14H10O4Ru
343.29
0.47, 0.39, 0.08
Triclinic
P1
7.133(1)
9.927(2)
10.029(2)
70.80(1)
74.35(1)
85.44(1)
645.8(2)
2
C14H12O4Ru
345.31
0.27, 0.23, 0.12
Monoclinic
C2/c
27.464(5)
15.796(2)
7.755(1)
90
94.11(2)
90
3355.5(10)
8
1.367
0.939
1376
Space group
˚
a (A)
˚
b (A)
˚
c (A)
h (°)
i (°)
k (°)
3
˚
V (A )
Z
Dcalc. (Mg m−3
)
1.520
0.752
502
1.625
1.010
776
1.766
1.219
340
v(Mo–Kh) (mm−1
F(000)
)
q range (°)
2.6–25.0
0.801, 0.871
3842
3818
0.025
2.8–25.0
0.546, 0.641
3463
2788
0.019
3.0–27.5
0.690, 0.921
3778
2633
0.009
2.6–22.5
0.297, 0.391
2872
2201
0.024
Min/max transmission
No. reflections collected
Unique reflections
Rint
Observed reflections [Fo\4|(Fo)]
R1 [Fo\4|(Fo)]
3624
0.026
2492
0.027
2541
0.016
1543
0.049
wR2 (all data)
0.069
0.086
0.043
0.169
Goodness-of-fit
Dzmax, Dzmin (e A
1.074
1.02, −0.69
1.073
0.77, −0.80
1.085
0.31, −0.46
1.090
0.708, −0.624
−3
˚
)
a Details in common: Stoe` Stadi-4 diffractometer operating at 150(2) K{220(2)K for 10}; ꢀ-q scan mode with learnt profile fitting (ꢀ scan mode
˚
for 10); graphite monochromated Mo–Kh radiation (u=0.71073 A); absorption corrections from semi-empirical „ scans; full-matrix least-squares
refinement on F2o where the function minimised was
%ꢀꢀFoꢀ−ꢀFcꢀꢀ
Sw(F2o−F2c)2; R1=
%ꢀFoꢀ
[Sw(F2−F2)2]
'
o
c
wR2=
,
SwF4o
where w−1=|2(F2o)+(xP)2+yP and P=(Fo2+2F2c)/3.
lP(CDCl3) 166.8; lC(CDCl3) 200.2 (2 C, d, JPC=7.5 Hz,
CO), 143.1 (2 C, ipso-Ar), 128.1 (4 C, o-Ar), 125.3 (2 C,
m-Ar), 124.6 (4 C, p-Ar), 82.1 (2 C, CHꢁCH–CHꢁCH),
54.6 (2 C, CHꢁCH–CHꢁCH), 51.2 (3 C, d, JPC=1.6 Hz,
CH3).
30% ethyl actetate–hexane mixture to afford the desired
product as a white crystalline material (Rf=0.37, 0.075
g, 83.7%) [Found: C, 48.8; H 3.4; m/z 346 [MH]+.
C14H12O4Ru requires C, 48.70; H, 3.50%; M (based on
101Ru) 345], w˜max cm−1 (pentane) 2067s, 2005vs, 1993s
(CO); lH(CDCl3) 7.06–7.26 (5 H, m, Ar), 5.84–5.89 (1
H, m, Ar–CHꢁCH), 5.42–5.47 (1 H, m, CHꢁCH–
CH2OH), 3.60–3.83 (2 H, m, CH2), 2.52 (1 H, d, J=8.6
Hz, Ar–CH), 1.62–1.71 (1 H, m, CH–CH2OH), 1.46 (1
H, s, br, OH); lC(CDCl3) 141.0 (1 C, ipso-Ar), 128.5 (2
C, o-Ar), 125.7 (1 C, p-Ar), 125.4 (2 C, m-Ar), 84.6 (1
C, Ar–CHꢁCH), 84.0 (1 C, CHꢁCH–CH2OH), 65.2 (1
C, CH2), 55.1 (1 C, Ar–CH), 54.1 (1 C, CH–CH2OH).
3.10. [Ru(CO)3{(E,E)-5-phenylpenta-2,4-dienol}] (10)
To a solution of 5 (0.100 g, 0.258 mmol) in THF (50
cm−3) at −78°C was added diisobutylaluminium hy-
dride (0.57 cm−3; 1 M in hexane, 0.568 mmol). The
resulting solution was allowed to warm to r.t. and stirred
for 1 h, at which point complete consumption of 5 was
indicated by thin layer chromatography. The reaction
mixture was quenched with water and the organic layer
washed successively with 2 M HCl and a saturated NaCl
solution. The organic phase was dried and the solvent
removed to yield a pale yellow oil, which was purified by
preparative thin layer chromatography eluting with a
4. Crystallography
A summary of crystal data and parameters associated
with data collection, structure solution and refinement

310
S.L. Ingham, S.W. Magennis / Journal of Organometallic Chemistry 574 (1999) 302–310
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is given in Table 5. The structures were solved by a
combination of Patterson methods and Fourier tech-
niques. Hydrogen atoms of the coordinated diene moi-
eties (and aldehyde hydrogen for 6) were located from
Fourier difference electron density syntheses and al-
lowed to refine without constraint. All remaining hy-
drogen atoms were placed in calculated positions and
refined using a riding model with individual isotropic
thermal parameters allowed to refine freely. Anisotropic
thermal motion was assumed for all non-hydrogen
atoms. The crystallographic computing programs
SHELXS-86 and SHELXL-93 were used throughout
the structure solution and refinement process [41,42].
Atomic coordinates, thermal parameters and bond
lengths and angles have been deposited at the Cam-
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We gratefully acknowledge Dr S. Parsons for the
collection of single crystal X-ray diffraction data and
the University of Edinburgh for financial support.
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