Reactions of Ru(C≡CPh)(PPh3)2Cp* with tetracyanoethene: Cycloaddition, formation of unusual η2-CNR complexes and oligomerisation via bridging cyanocarbon ligands

Article abstract of DOI:10.1039/b105131h

Thermolysis of Ru{ η³-C(CN)₂CPhC=C(CN)₂}(PPh₃) Cp* (2), obtained from Ru(C≡CPh)(PPh₃)₂Cp* and tetracyanoethene, has given the three complexes Ru{ η¹,η²(C,N)-C(CN)=C(CN)CPh=C(CN)(C=N)}(PPh ₃)Cp* (3), {Ru(PPh₃)Cp*}{μ-N:η³-NCC(CN)=CPhC=C(CN) ₂}{μ-η¹:N-C(CN)=C(CN)CPh=C(CN)₂} {RuCp*} (4) and {Ru[η³-C(CN)₂=CPhC=C(CN)₂]Cp*} ₃ (5). All four complexes have been characterised by single-crystal X-ray structure determinations and contain isomeric forms of the C₄(CN)₄Ph ligand. Unusual features of the molecular structures are (i) the presence of a side-on (η²) CN group in 3; (ii) formation of a second isomer of the polycyanocarbon ligand by CN migration to an adjacent carbon, in 3 and 4; (iii) the use of one or more CN groups to bridge ruthenium centres in 4 and 5; and (iv) the complete loss of PPh₃ ligands during the formation of the trimer 5. Although there are three crystallographically distinct RuCp* groups in 5, only one Cp* resonance is found in solution NMR spectra, suggesting that oligomer formation by facile CN-Ru bond breaking and making is occurring.

Full text of DOI:10.1039/b105131h

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᎐
Reactions of Ru(C᎐CPh)(PPh ) Cp* with tetracyanoethene:
᎐
3 2
cycloaddition, formation of unusual ꢀ2-CNR complexes and
oligomerisation via bridging cyanocarbon ligands
Michael I. Bruce,a Brian W. Skelton,b Allan H. Whiteb and Natasha N. Zaitsevaa
a Department of Chemistry, Adelaide University, Adelaide, South Australia 5005
b Department of Chemistry, University of Western Australia, Crawley, Western Australia 6009
Received 12th June 2001, Accepted 3rd October 2001
First published as an Advance Article on the web 13th November 2001
3
᎐
Thermolysis of Ru{η -C(CN) CPhC᎐C(CN) }(PPh )Cp* (2), obtained from Ru(C᎐CPh)(PPh ) Cp* and
᎐
᎐
2
2
3
3 2
tetracyanoethene, has given the three complexes Ru{η1,η2(C,N)-C(CN)᎐C(CN)CPh᎐C(CN)(C᎐N)}(PPh )Cp* (3),
᎐
᎐
᎐
3
{Ru(PPh )Cp*}{µ-N:η3-NCC(CN)᎐CPhC᎐C(CN) }{µ-η1:N-C(CN)᎐C(CN)CPh᎐C(CN) }{RuCp*} (4) and
᎐
᎐
᎐
᎐
3
2
2
{Ru[η3-C(CN) ᎐CPhC᎐C(CN) ]Cp*} (5). All four complexes have been characterised by single-crystal X-ray
᎐
᎐
2
2
3
structure determinations and contain isomeric forms of the C4(CN)4Ph ligand. Unusual features of the molecular
structures are (i) the presence of a side-on (η2) CN group in 3; (ii) formation of a second isomer of the polycyano-
carbon ligand by CN migration to an adjacent carbon, in 3 and 4; (iii) the use of one or more CN groups to bridge
ruthenium centres in 4 and 5; and (iv) the complete loss of PPh3 ligands during the formation of the trimer 5.
Although there are three crystallographically distinct RuCp* groups in 5, only one Cp* resonance is found in
solution NMR spectra, suggesting that oligomer formation by facile CN–Ru bond breaking and making is occurring.
metal centre has also been observed,5 in one case giving
Introduction
a macrocyclic complex containing a 10-membered ring.6
Cycloaddition of electron-deficient alkenes to transition metal
However, apart from these, to our knowledge no further
elaboration of the polycyanocarbon ligand has been reported.
σ-alkynyl complexes was first reported in 19791 and has been
extensively investigated since then.2,3 The initial product is a
Much of our earlier work was carried out with the Ru-
deeply coloured radical species, although this is not always
(PPh3)2Cp fragment, where the ready loss of one PPh3 ligand
observed, which fades rapidly (minutes) to the colour of
the product. The first complex which has been isolated is the
σ-cyclobutenyl (A, Scheme 1) which then undergoes a ring-
encourages the formation of complexes of type C. Recently,
we and others have described a series of σ-alkynyls containing
the Ru(PPh3)2Cp* fragment.7 Many of the compounds were
derived from a neutral vinylidene complex by loss of HCl in
the presence of a ligand L (O2, S2, C2H4, etc.).8 We now report
᎐
some chemistry of the complex Ru(C᎐CPh)(PPh ) Cp* (1)
᎐
3
2
with tcne and some subsequent reactions of the polycyano
ligand (Schemes 2 and 3).
Scheme 1
opening reaction to give the buta-1,3-dien-2-yl complex B.
Where there is a labile ligand attached to the metal centre, its
loss results in the formation of the η3-allylic species C. This
derivative has a short M–C σ bond and is better considered as a
zwitterion attached via an M᎐C(sp2) multiple bond. Addition
᎐
of other 2e ligands may reverse the last reaction to give other
complexes of type B.
When tetracyanoethene, C2(CN)4 (tcne), is used, the resulting
products are stable and do not readily enter into further
reactions. In two cases, hydrolysis or methanolysis of one
CN group has been reported to give chelating hydroxy- or
alkoxy-imine derivatives.2e,4 Further coordination of a second
Scheme 2
DOI: 10.1039/b105131h
J. Chem. Soc., Dalton Trans., 2001, 3627–3633
This journal is © The Royal Society of Chemistry 2001
3627

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groups resonate as a singlet at δ 8.53; the Cp* ring carbons
give a doublet at δ 101.08, however. Apart from C(3) and C(4),
other carbon atoms in the polycyano ligand give rise to doublet
resonances between δ 116.69 and 191.19; the latter is assigned
to C(11) by analogy with the resonance at δ 235 found for
[WCl(η2-NCMe)(PMe3)2(bpy)]ϩ.9 The ES mass spectrum of
a solution containing NH4OH gives [M ϩ NH4]ϩand Mϩ ions
at m/z 746 and 728, respectively.
The second product, obtained in 13% yield, forms red
crystals and is formulated as {Ru(PPh3)Cp*}{µ-N:η3-NCC-
(CN)᎐CPhC᎐C(CN) }{µ-η1:N-C(CN)᎐C(CN)CPh᎐C(CN) }-
᎐
᎐
᎐
᎐
2
2
{RuCp*} (4) from the X-ray structure determination. The
two polycyano ligands differ, one being attached to Ru(1) via a
C–Ru σ-bond and N–Ru donor bond, the other to Ru(2) in the
η3-allylic mode and by an N-donor bond. Major structural
details are discussed below, but in general they are similar
to those found for these ligands on earlier occasions.2 The IR
spectrum contains ν(CN) bands at 2213, 2078 and 2017 cmϪ1
while Mϩ is found at m/z 1194.
,
The major product (52%) is a trimer, {Ru[η3-C(CN) ᎐CPhC᎐
᎐
᎐
2
C(CN)2]Cp*}3 (5), as shown by the X-ray structure determin-
ation. This complex is unusual in not containing any PPh3
ligands and in having the same cyanocarbon ligand with three
different bonding modes, that is, a “normal” η3 system to
Ru(3), an η3 system on Ru(1) also bridging via one CN to
Ru(2), and the third η3 system on Ru(2) which uses two CN
groups to bridge to Ru(1) and Ru(3). Only two ν(CN) bands are
found, at 2215 and 2126 cmϪ1. The 1H NMR spectrum contains
only one Me resonance, at δ 1.56, suggesting that there may
be some fluxional process which renders all Cp* Ru groups
equivalent on the NMR time scale. However, there was no
change in the NMR spectra at the lowest temperature we were
able to record (218 K) when precipitation started to occur.
Ready loss of a Ru{PhC4(CN)4} group from the [M ϩ Na]ϩ ion
is found in the ES mass spectrum, obtained in the presence of
NaOMe.
On one occasion, a small amount of a complex identified
from an X-ray structure determination as Ru{η1,η2(C,N)-
C(CH᎐CHPh)᎐CPhC[CPh᎐C(CN) ]᎐C(CN)(C᎐N)}(PPh )-
᎐
᎐
᎐
᎐
᎐
2
3
Cp* (6, Scheme 4) was obtained from the reaction of 1 with
Scheme 3
Results and discussion
The reaction between 1 and tcne was carried out in benzene
at rt for 24 h. The only detectable product is the η3-allylic
complex, Ru{η3-C(CN) CPhC᎐C(CN) }(PPh )Cp* (2), which
᎐
2
2
3
forms orange crystals in 73% yield. This complex was readily
identified by microanalysis and spectroscopic methods. In
common with earlier studies, the IR spectrum contained few
characteristic bands apart from ν(CN) at 2215 cmϪ1. The
1H NMR spectrum contains a doublet for the Cp* Me
groups at δ 1.35, which with the 15/20 ratio of this resonance
and the Ph multiplet indicates the presence of only one PPh3
ligand on the ruthenium centre. Similarly, the ES mass
spectrum contains [M ϩ H]ϩ at m/z 729. The molecular
structure of 2 was determined from a single-crystal X-ray study
(see below).
Scheme 4
tcne. However, it was later established that a corresponding
3
8
᎐
amount of Ru{η -CHPh᎐CHC᎐CPh(C᎐CPh)}(PPh )Cp* (7)
᎐
᎐
᎐
3
was present as an impurity in the sample of 1 and an indepen-
dent experiment showed that 6 was formed in 51% yield
in the reaction of pure 7 with tcne.10 Compound 6 also has
a side-on η2-CN ligand, the tcne apparently adding to the
᎐
Thermolysis of 2 in refluxing benzene overnight and
separation by preparative t.l.c. gives three fractions. From the
fastest running fraction, purple crystals of Ru{η1,η2(C,N)-
non-coordinated C᎐CPh group in 7. Preparative t.l.c. separated
᎐
the dark green product into two closely running bands,
which each gave dark green solids after work-up. However, the
spectroscopic properties (IR, NMR) of the two fractions were
identical and further chromatography of each fraction gave the
same two bands. X-Ray structure determinations of crystals
obtained from each fraction were also identical, although it is
entirely possible that the same (least soluble) isomer was
obtained in each case. It is likely therefore that these two
materials are isomers, either conformational or by exchange of
coordinated and free CN groups.
C(CN)᎐C(CN)CPh᎐C(CN)(C᎐N)}(PPh )Cp* (3) were isolated
᎐
᎐
᎐
3
in 16% yield. Complex 3 is an isomer of 2, the X-ray molecular
structure determination revealing two unusual features: one of
the CN groups has migrated to an adjacent carbon atom, while
another is η2-bonded (side-on) to the ruthenium atom. The
IR spectrum contains ν(CN) bands at 2209 and 2170 cmϪ1
.
1
The H NMR spectrum contains a doublet for the Cp* Me
groups at δ 1.51, while in the 13C NMR spectrum, these Me
3628
J. Chem. Soc., Dalton Trans., 2001, 3627–3633

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Molecular structures
For 2, 3 and 4, common features are the Ru(PPh3)Cp*
groups, which have structural parameters similar to those
reported earlier. Thus, the Ru–P distances range between
2.3520(7) and 2.4013(8) Å, while the average Ru–C(Cp*)
separations are between 2.22(4) and 2.28(3) Å, internal
precision being much better and indicative of some asymmetry
in the ring–metal binding, e.g. in 2, 3 or 4 where individual
values range between 2.230 and 2.313(3) Å. Evidently,
intramolecular steric interactions with the ring Me groups,
which lie well out of the C5 ring planes in some cases (up to
ca. 0.3 Å, visibly so in some of the Figures), result in a soft
attachment of the C5 ring to the metal. The η3-cyanocarbon
ligands in 2, 4 and 5 are also common, differing only in whether
or not they are also attached to a second (or third) Ru centre by
one of the CN groups. Bond parameters are similar to those
reported in earlier examples and do not warrant detailed
discussion.
The natures of 2, 3, 4 and 5 were confirmed or determined from
single-crystal X-ray structure determinations; the structure of 6
has been reported previously,10 but is further discussed below.
Plots of these molecules are shown in Figs. 1–4 and selected
structural data are given in Tables 1 and 2.
The formation of the C(CN) CPhC᎐C(CN) ligands by
᎐
2
2
addition of tcne to the σ-phenylethynyl ligand in 1 occurs via
the reactions that have previously been described.2 In 3 and 4,
one of the cyanocarbon ligands has been formed by an unusual
migration of a CN group to an adjacent carbon atom in the
chain (Scheme 5). In 3, chelation occurs by η2 bonding of a CN
to Ru, whereas in 4, a CN group is N-bonded to the second Ru
atom. The unusual chemistry found here, which does not occur
under the same or harsher conditions with the Cp analogue,
involves η2 coordination of a CN group (in 3) and migration of
a CN group (in 3 and 4). The presence of the strongly electron-
donating Cp* group increases electron density at the Ru
centre so that stabilisation of the η2-CN arrangement by
back-bonding from the metal to the CN π* orbitals can occur.
This is confirmed by a lengthening of the coordinated C–N
bond, as shown by comparison of C(11)–N(11) [1.212(3) Å]
with the non-coordinated C(12)–N(12) group [1.142(3) Å]
on the same C(1) atom, together with the bending of the
C(1)–C(11)–N(11) angle by 35.4(2)Њ from the normal linear
arrangement [cf. C(1)–C(12)–N(12) 176.6(2)Њ]. That this type of
coordination occurs may be the result of steric pressures in the
Fig. 1 Plot of a molecule of Ru{η3-C(CN)2CPhC᎐C(CN)2}(PPh3)Cp*
᎐
(2), showing atom numbering scheme.
alternative η2-C(1)᎐C(2) arrangement that would have been
᎐
expected.
A possible sequence of reactions is outlined in Scheme 5.
Migration of a CN group from C(4) to Ru generates a
zwitterionic intermediate, represented as D. A related complex,
Fig. 2 Plot of a molecule of Ru{η1,η2(C,N)-C(CN)᎐C(CN)CPh᎐
Ru(CN){C(CN)C[CPh᎐C(CN) ]PPh CH PPh }Cp*, has been
᎐
2
2
2
2
᎐
᎐
described.10 Intermediate D may evolve in several ways. Further
C(CN)(C–N)}(PPh3)Cp* (3).
Fig. 3 Plot of a molecule of {Ru(PPh3)Cp*}{µ-N:η3-NCC(CN)᎐CPhC᎐C(CN)2}{µ-η1:N-C(CN)᎐C(CN)CPh᎐C(CN)2}{RuCp*} (4), with H atoms
᎐
᎐
᎐
᎐
omitted for clarity.
J. Chem. Soc., Dalton Trans., 2001, 3627–3633
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Scheme 5
Fig. 4 Plot of a molecule of {Ru[η3-C(CN)2᎐᎐CPhC᎐C(CN)2]Cp*}3 (5), with H atoms omitted for clarity.
᎐
migration of the CN group to the β-carbon, C(3), of the vinyl
group, results in isomerisation of the cyanocarbon ligand, as
found in 3. At the same time, a vacant coordination site on
Ru is generated which, in the absence of a suitable ligand, is
occupied by a CN group on C(1), bonding in the η2 mode.
The formation of 4 occurs by addition of a second molecule
of 2 (RCN in Scheme 5) to intermediate D via coordination of a
CN lone-pair, with concomitant loss of PPh3. In 4, which con-
tains the two isomeric forms of the cyanocarbon ligand, Ru(1)
originates from 3, while Ru(2) comes from 2. Finally, formation
of 5 occurs by trimerisation of 2, without isomerisation, but
with loss of all PPh3 ligands. This complex contains the original
cyanocarbon ligand bonding in three different modes.
that the CN-migration reaction may proceed via a zwitterionic
intermediate D. It is possible that attack of an alternative
anionic centre or electron-rich neutral atom, may further
elaborate the original cyanocarbon, as found in Ru(CN)-
{C(CN)C[CPh᎐C(CN) ]PPh CH PPh }Cp*.10 The ready loss
᎐
2
2
2
2
of a PPh3 ligand from Ru(PPh3)2CpЈ (CpЈ = Cp or Cp*)
complexes may lead to the formation of macrocyclic complexes,
as found earlier,6 or oligomeric species such as 5, as found here.
These reactions are relevant to the intramolecular oxidative
addition reaction whereby NiPh(CN)(dippe) [dippe = 1,2-bis-
(di-iso-propylphosphino)ethane] is formed reversibly from the
η2-nitrile complex Ni(η2-NCPh)(dippe)11 and may also pertain
to the alkylation of molybdenum–η2-NCMe complexes.12
Conclusions
Experimental
We have demonstrated novel isomerisation reactions which are
undergone by the cyanocarbon ligand formed by addition of
tetracyanoethene to the phenylethynyl ligand in 1. We suggest
General reaction conditions
Reactions were carried out under an atmosphere of nitrogen,
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J. Chem. Soc., Dalton Trans., 2001, 3627–3633

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Table 1 Selected bond distances (Å) and angles (Њ) for 2, 3 and 6
2
3
6a
Ru–P
Ru–C(Cp*)
(av.)
2.4013(8)
2.230–2.313(3)
2.27(4)
2.3574(6)
2.239–2.304(2)
2.28(3)
2.3520(7)
2.234–2.304(3)
2.27(3)
Ru–C(1)
Ru–C(2)
2.210(3)
2.162(3)
Ru–C(3)
Ru–C(4)
1.973(3)
2.044(2)
2.079(2)
2.211(2)
1.369(3)
1.436(3)
1.455(3)
1.395(3)
2.097(3)
2.061(3)
2.208(2)
1.382(4)
1.423(3)
1.445(4)
1.378(3)
1.471(4)
1.343(5)
1.436(9)
1.215(3)
1.141(4)
1.139(3)
Ru–C(11)
Ru–N(11)
C(1)–C(2)
C(1)–C(11)
C(2)–C(3)
C(3)–C(4)
C(4)–C(5)
C(5)–C(6)
C–CN (av.)
C(11)–N(11)
C(12)–N(12)
C–N (av.)
1.484(4)
1.425(4)
1.357(4)
1.443(7)
1.143(4)
1.149(4)
1.143(7)
1.441(9)
1.212(3)
1.142(3)
1.148(9)
P–Ru–C(1)
P–Ru–C(3)
90.36(8)
89.37(8)
P–Ru–C(4)
P–Ru–C(11)
P–Ru–N(11)
89.63(6)
91.12(6)
85.27(5)
90.13(7)
97.40(8)
87.09(7)
C(1)–Ru–C(3)
C(4)–Ru–C(11)
C(4)–Ru–N(11)
C(2)–C(1)–C(11)
C(1)–C(2)–C(3)
C(2)–C(3)–C(4)
C(3)–C(4)–C(5)
C(4)–C(5)–C(6)
Ru–C(11)–C(1)
Ru–C(4)–C(3)
C(1)–C(11)–N(11)
71.1(1)
81.01(8)
113.02(7)
122.3(2)
120.9(2)
125.7(2)
82.1(1)
113.23(9)
120.1(3)
124.7(2)
124.4(3)
117.4(3)
124.2(3)
114.0(2)
134.9(2)
135.7(2)
133.7(2)
145.5(3)
a Ref. 10.
but no special precautions were taken to exclude oxygen during
work-up. Common solvents were dried and distilled under
nitrogen before use. Elemental analyses were performed by the
Canadian Microanalytical Service, Delta, B.C., Canada.
Preparative t.l.c. was carried out on glass plates (20 × 20 cm)
coated with silica gel (Merck 60 GF254, 0.5 mm thickness).
1535w, 1483m, 1437m, 1378m cmϪ1. 1H NMR: δ 1.35 [d, J(HP)
1.2 Hz, 15H, Me], 6.95–7.72 (m, 20H, Ph). 31P NMR: δ 46.75
(s, PPh3). ES mass spectrum (MeOH–CH2Cl2 ϩ NH3, m/z):
746, [M ϩ NH4]ϩ; 729, [M ϩ H]ϩ.
Thermolysis of 2. A solution of 2 (140 mg, 0.19 mmol) in
benzene (15 ml) was heated at reflux point overnight. After
evaporation of benzene, the residue was dissolved in acetone
and separated by preparative t.l.c. (acetone–hexane 3/7) into
three fractions. Band 1 (Rf 0.51) gave purple crystals (CH2Cl2–
MeOH) of Ru{η1,η2(C,N)-C(CN)᎐C(CN)CPh᎐C(CN)(C–N)}-
Instrumentation
IR: Perkin-Elmer 1720X FT IR. NMR: Bruker CXP300 or
ACP300 (1H at 300.13 MHz, 13C at 75.47 MHz) or Varian
Gemini 200 (1H at 199.8 MHz, 13C at 50.29 MHz) spectro-
meters. Spectra were recorded using solutions in CDCl3 in 5
mm sample tubes. ES mass spectra: Finnegan LCQ. Solutions
were directly infused into the instrument. Chemical aids to
ionisation were used as required.13
᎐
᎐
(PPh3)Cp* (3) (23.8 mg, 16.4%). Anal. Found: C, 68.17; H, 5.08;
N, 7.47. Calc. for C42H35N4PRuؒMeOH: C, 67.97; H, 5.17;
N, 7.37%; M, 728. IR (CH2Cl2): ν(CN) 2209m, 2170m; other
bands at 1605s, 1541m, 1482m, 1438m, 1378m cmϪ1. 1H NMR:
δ 1.51 [d, J(HP) 1.8 Hz, 15H, Me], 7.28–7.82 (m, 20H, Ph). 13
C
NMR: δ 8.53 (s, Me), 101.08 [d, J(CP) 2.56 Hz, Cp*],
115.72 [s, C(3)], 116.69 [d, J(CP) 2.56 Hz, C(31)N], 122.97
[d, J(CP) 3.99 Hz, C(8)N], 124.46 [d, J(CP) 3.16 Hz, C(3)],
128.01–130.52 (m, Ph), 136.12 [s, C(2)], 143.03 [d, J(CP) 2.03
Hz, C(41)N], 158.70 [d, J(CP) 2.86 Hz, C(4)], 191.19 [d, J(CP)
14.56 Hz, C(11)]. 31P NMR: δ 44.13 (s, PPh3). ES mass spectrum
(MeOH containing NH4OH, m/z): 746, [M ϩ NH4]ϩ; 728, Mϩ.
Band 2 (Rf 0.43) afforded {RuCp*}{µ-N:η3-C[᎐C(CN) ]-
Reagents
Complexes 17b and 78 were prepared as previously described.
tcne (Aldrich) was sublimed before use.
᎐
Reaction of Ru(C᎐CPh)(PPh ) Cp* with tcne. A mixture of
᎐
3
2
᎐
Ru(C᎐CPh)(PPh ) Cp* (74 mg, 0.09 mmol) and tcne (22 mg,
᎐
3
2
0.18 mmol) in benzene (7 ml) was stirred at rt for 24 h. Removal
of solvent and purification of a CH2Cl2 extract of the residue
by preparative t.l.c. (acetone–hexane 3/7) gave a single orange
band (Rf 0.4). Extraction and crystallisation (CH2Cl2–MeOH)
᎐
2
CPhC(CN) }{µ-η1:-N-C(CN)᎐C(CN)CPh᎐C(CN) }{Ru(PPh )-
᎐
᎐
2
2
3
Cp*} (4) (14.5 mg, 12.6%) as dark red crystals (CH2Cl2–
MeOH). Anal. Found: C, 62.72; H, 4.58; N, 8.57. Calc. for
C66H55N8PRu2ؒCH2Cl2: C, 62.91; H, 4.46; N, 8.78%; M, 1194.
IR (CH2Cl2): ν(CN) 2213m, 2078w, 2017w; other bands at
gave orange crystals of Ru{η3-C(CN) CPhC᎐C(CN) }(PPh )-
᎐
2
2
3
Cp* (2) (45.3 mg, 72.5%). Anal. Found: C, 68.45; H, 4.91; N,
7.60. Calc. for C42H35N4PRu: C, 69.23; H, 4.80; N, 7.69%;
M, 728. IR (CH2Cl2): ν(CN) 2215s; other bands at 1579m,
1
1602m, 1555m, 1539w, 1434m, 1335m cmϪ1. H NMR: δ 1.41
(s, 15H, Cp*), 1.67 [d, J(HP) 1.5 Hz, 15H, Cp*], 6.56–7.69
J. Chem. Soc., Dalton Trans., 2001, 3627–3633
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1377m cmϪ1. 1H NMR: δ 1.56 (s, 45H, Cp*), 7.37–7.57 (m, 15H,
Ph). ES mass spectrum (MeOH containing NaOMe, m/z): 1420,
[M ϩ Na]ϩ; 955, [M ϩ Na Ϫ Ru{PhC4(CN)4}]ϩ.
Table 2 Selected bond distances (Å) and angles (Њ) for 4 and 5
4
5
Ru–P
Ru(1)–C(Cp*)
(av.)
Ru(2)–C(Cp*)
(av.)
Ru(3)–C(Cp*)
(av.)
2.3618(8)
2.194–2.271(2)
2.24(3)
2.179–2.276(3)
2.22(4)
3
᎐
Reaction of Ru{ꢀ -CHPh᎐CHC᎐CPh(C᎐CPh)}(PPh )Cp*
᎐
᎐
᎐
3
2.171–2.283(6)
2.22(4)
2.172–2.298(5)
2.23(5)
2.174–2.305(5)
2.23(6)
(7) with tcne. When tcne (8 mg, 0.06 mmol) was added to a
solution of Ru{η -CHPh᎐CHC᎐CPh(C᎐CPh)}(PPh )Cp* (7)
3
᎐
᎐
᎐
᎐
3
(50 mg, 0.06 mmol) in benzene (5 ml), the mixture immediately
turned dark green. After 30 min at rt, no starting complex
was present. Evaporation, extraction of the residue with thf
and separation by preparative t.l.c. (acetone–hexane 3/7) gave
two closely running deep green bands as the major product.
Dark green solids were obtained after extraction (Rf 0.49, 10
mg; Rf 0.47, 19.5 mg). Both materials have identical physical
properties and are probably isomers. Rechromatography of
each band separately also generates two green bands. Crystal
structures of products from each band were determined,
but were identical, suggesting that in each case, the same
isomer is preferentially crystallised. The complex was identified
Ru(1)–C(14)
Ru(2)–C(11)
Ru(2)–C(12)
Ru(2)–C(13)
Ru(2)–C(21)
Ru(2)–C(22)
Ru(2)–C(23)
Ru(3)–C(31)
Ru(3)–C(32)
Ru(3)–C(33)
Ru(1)–N(11)
Ru(2)–N(11)
Ru(3)–N(141)
C(11)–C(12)
C(11)–C(111)
C(12)–C(13)
C(13)–C(14)
C(14)–C(141)
C(21)–C(22)
C(21)–C(211)
C(23)–C(24)
C(31)–C(32)
C(32)–C(33)
C(33)–C(34)
C–CN (av.)
C(111)–N(111)
C(141)–N(141)
C(211)–N(211)
C–N (av.)
2.032(2)
2.234(5)
2.159(4)
1.980(5)
2.226(5) [Ru(1)]
2.155(5) [Ru(1)]
1.975(5) [Ru(1)]
2.198(4)
2.171(5)
1.969(5)
2.044(4) [N(111)]
2.074(4) [N(211)]
2.031(4)
1.466(7)
1.432(7)
1.422(7)
1.347(7)
1.432(7)
1.475(7)
1.433(7)
1.358(7)
1.471(7)
1.429(7)
1.356(7)
1.436(7)
1.149(7)
1.143(6)
2.242(2)
2.163(2)
1.986(3)
2.034(2) [N(211)]
2.049(2) [N(141)]
as
Ru{η1,η2(N,C)-C(CH᎐CHPh)᎐CPhC[CPh᎐C(CN) ]᎐
᎐ ᎐ ᎐ ᎐
2
C(CN)(C᎐N)}(PPh )Cp* (6) by X-ray crystallography. Anal.
Found: C, 74.03; H, 5.18; N, 5.98. Calc. for C58H47N4P2Ru: C,
᎐
3
1.363(6)
74.74; H, 5.08; N, 6.01%; M, 932. IR (CH2Cl2): ν(CN) 2230w,
1.483(4)
1.368(4)
1.461(4)
1.458(4)
1.432(3)
1.353(4)
2208s; other bands at 1597m, 1561m, 1524w, 1490s, 1371s cmϪ1
.
1H NMR: δ 1.44 [d, J(HP) 1.4 Hz, 15H, Cp*], 3.34 [d, J(HH)
16 Hz, 1H, ᎐CH], 4.41 [d, J(HH) 16 Hz, 1H, ᎐CH], 5.92–7.33
᎐
᎐
(m, 30H, Ph). 31P NMR: δ 48.75 (s), 50.34 (s). ES mass
spectrum (CH2Cl2–MeOH, m/z): 934, [M ϩ 2H]ϩ; 672,
[M ϩ 2H Ϫ PPh3]ϩ.
Structure determinations
1.44(1)
Full spheres of diffraction data were measured at ca. 153 K
using a Bruker AXS CCD area-detector instrument. Ntot
reflections were merged to Nunique (Rint quoted) after
“empirical”/multiscan absorption correction (proprietary
software), No with F > 4σ(F) being used in the full matrix
least squares refinement. All data were measured using
monochromatic Mo-Kα radiation, λ = 0.71073 Å. Anisotropic
thermal parameter forms were refined for the non-hydrogen
atoms, (x, y, z, Uiso)H being constrained at estimated values.
Conventional residuals R, Rw on |F| are given [weights: (σ2(F) ϩ
0.0004F 2)Ϫ1]. Neutral atom complex scattering factors
were used; computation used the Xtal 3.7 program system.14
Pertinent results are given in the Figures (which show non-
hydrogen atoms with 50% probability amplitude displacement
envelopes and hydrogen atoms with arbitrary radii of 0.1 Å)
and Tables 1–3.
1.170(3)
1.146(3)
1.142(6)
1.149(7)
1.144(8)
P–Ru(1)–C(14)
P–Ru(1)–N(211)
94.31(9)
86.75(7)
87.90(9)
68.6(1)
C(14)–Ru(1)–N(211)
C(21)–Ru(2)–C(23)
C(11)–Ru(2)–N(211)
C(13)–Ru(2)–N(211)
C(21)–Ru(2)–N(141)
C(23)–Ru(2)–N(141)
C(31)–Ru(3)–N(141)
C(33)–Ru(3)–N(141)
C(12)–C(11)–C(111)
C(11)–C(12)–C(13)
C(12)–C(13)–C(14)
C(13)–C(14)–C(141)
C(22)–C(21)–C(211)
C(21)–C(22)–C(23)
C(22)–C(23)–C(24)
C(31)–C(32)–C(33)
C(32)–C(33)–C(34)
Ru(1)–N(111)–C(111)
Ru(2)–N(211)–C(211)
Ru(3)–C(141)–N(141)
Ru(1)–C(14)–C(13)
Ru(1)–C(14)–C(141)
C(11)–C(111)–N(111)
C(14)–C(141)–N(141)
C(21)–C(211)–N(211)
89.7(2)
89.1(2)
88.58(8)
91.06(9)
88.4(2)a
91.9(2)a
90.0(2)
89.6(2)
117.1(4)
110.2(4)
140.2(4)
122.4(5)
123.6(3)
127.6(3)
115.9(2)
120.4(2)
111.3(2)
132.0(2)
Variata. Complex 3. (x, y, z, Uiso)H were refined. Difference
map residues were modelled as methanol, seemingly hydrogen-
bonded to CN(41) of the cyanocarbon ligand [N(41) ؒ ؒ ؒ H,O-
(x, 2 Ϫ y, z) 1.90(4), 2.915(3) Å]. C(41)–N(41) [1.158(3) Å] may
be slightly elongated in consequence.
Complex 4. Difference map residues were most satisfactorily
modelled as two MeCN molecules, one disordered over two sets
of sites, occupancies set at 0.5 after trial refinement.
Complex 5. Difference map residues were modelled as three
Me2CO molecules; displacement amplitudes on the latter
were high, particularly on molecule ‘3’ which was refined with
isotropic displacement parameters and constrained geometries.
CCDC reference numbers 165410–165413.
111.6(4)
139.7(5)
166.9(4)
164.0(4)
177.9(4)
170.4(2)
132.1(2)
111.9(2)
174.8(5)
179.4(5)
175.6(5)
171.2(3)
172.9(2)
a Values for C(21)–Ru(1)–N(111), C(23)–Ru(1)–N(111).
(m, 25H, Ph). 31P NMR: δ 43.58 (s, PPh3). ES mass spectrum
(MeOH containing NaOMe, m/z): 1217, [M ϩ Na]ϩ; 1194, Mϩ;
955, [M ϩ Na Ϫ PPh3]ϩ.
See http://www.rsc.org/suppdata/dt/b1/b105131h/ for crystal-
lographic data in CIF or other electronic format.
Band 3 (Rf 0.32) gave orange crystals (acetone–hexane) of
Acknowledgements
{Ru[η3-C(CN) ᎐CPhC᎐C(CN) ]Cp*} (5) (46 mg, 52%). Anal.
᎐
᎐
2
2
3
Found: C, 61.52; H, 4.40; N, 11.52. Calc. for C72H60N12Ru3: C,
61.92; H, 4.33; N, 12.03%; M, 1397. IR (CH2Cl2): ν(CN)
2215m, 2126w; other bands at 1603m, 1493w, 1449m, 1417m,
This work was supported by the Australian Research Council.
We thank Professor Brian Nicholson (University of Waikato,
New Zealand) for the mass spectra. We are grateful to Johnson
3632
J. Chem. Soc., Dalton Trans., 2001, 3627–3633

View Article Online
Table 3 Crystal data and refinement details for 2, 3, 4 and 5
Compound
2
3
4
5
Formula
MW
Crystal system
Space group
a/Å
b/Å
c/Å
C42H35N4PRu
727.8
Monoclinic
P21/c
9.831(1)
20.850(2)
17.600(2)
C42H35N4PRuؒCH4O
759.8
C66H55N8PRu2ؒ2C2H3N
1275.4
C72H60N12Ru3ؒ3C3H6O
1570.8
Orthorhombic
Pna21
28.509(3)
14.925(1)
Triclinic
Triclinic
¯
¯
P1
P1
10.404(1)
11.359(1)
15.436(2)
87.481(2)
84.698(2)
89.838(2)
1815
10.5347(6)
14.7397(9)
20.733(1)
89.675(1)
78.178(1)
74.698(1)
3035
17.749(2)
α/Њ
β/Њ
92.790(2)
γ/Њ
V/Å3
3603
7552
Z
4
2
2
4
Dc/g cmϪ3
µ/cmϪ1
Crystal size/mm
‘T ’min,max
2θmax/Њ
Ntot
1.341
5.1
0.28 × 0.25 × 0.22
0.68, 0.83
58
35503
9120 (0.038)
7132
1.414
5.2
0.22 × 0.19 × 0.13
0.74, 0.89
58
18058
8902 (0.024)
7503
1.506
5.8
0.30 × 0.25 × 0.20
0.71, 0.80
75
40562
10667 (0.036)
8875
1.381
6.5
0.35 × 0.28 × 0.12
0.68, 0.81
75
147610
19395 (0.073)
13477
N (Rint
No
)
R
Rw
0.040
0.052
0.033
0.037
0.051
0.059
0.043
0.043
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J. Chem. Soc., Dalton Trans., 2001, 3627–3633
3633