Reactions of Ru(C≡CPh)(L2)Cp* (L2 = dppm, dppe) with tetracyanoethene: Cycloaddition, formation of monodentate dppm and dppmO complexes and migration of CN to ruthenium

Article abstract of DOI:10.1016/S0022-328X(02)01202-0

The reaction of C₂(CN)4 with Ru(C≡CPh)(dppm)Cp* in THF has given the anticipated tetracyanobuta-1,3-dien-2-yl complex Ru{C[=C(CN)₂]CPh=C(CN)₂}(dppm)Cp* (3). In benzene, η³-cyano-enyl complexes complex 3 rearranges to the cyanoruthenium-ylid complex Ru(CN){C(CN)=C[CPh=C(CN)₂]PPh₂CH₂PPh ₂}Cp* (6). A possible reaction sequence, involving a zwitterionic intermediate such as Ru(δ-)(CN){C(CN)C(δ+)CPh=C(CN)₂}(dppm-P)Cp* D, is discussed. Only the η¹-dienyl complex 7 is obtained from Ru(C≡CPh)(dppe)Cp* and TCNE.

Full text of DOI:10.1016/S0022-328X(02)01202-0

Journal of Organometallic Chemistry 650 (2002) 141–150
www.elsevier.com/locate/jorganchem
Reactions of Ru(CꢀCPh)(L2)Cp* (L2=dppm, dppe) with
tetracyanoethene: cycloaddition, formation of monodentate dppm
and dppmO complexes and migration of CN to ruthenium
Michael I. Bruce a,*, Brian W. Skelton b, Allan H. White b, Natasha N. Zaitseva a
a Department of Chemistry, Adelaide Uni6ersity, Adelaide, South Australia 5005, Australia
b Department of Chemistry, Uni6ersity of Western Australia, Crawley, Western Australia 6009, Australia
Received 27 November 2001; accepted 11 January 2002
Abstract
The reaction of C2(CN)4 with Ru(CꢀCPh)(dppm)Cp* in THF has given the anticipated tetracyanobuta-1,3-dien-2-yl complex
Ru{C[ꢁC(CN)2]CPhꢁC(CN)2}(dppm)Cp* (3). In benzene, h3-cyano-enyl complexes Ru{h3-C[ꢁC(CN)2]CPhCC(CN)2}(L)Cp*
(L=dppm-P (4) or dppmO (5)) are formed, the latter by adventitious oxidation. On warming, complex 3 rearranges to the
cyanoruthenium–ylid complex Ru(CN){C(CN)ꢁC[CPhꢁC(CN)2]PPh2CH2PPh2}Cp* (6). A possible reaction sequence, involving a
zwitterionic intermediate such as Ru(d-)(CN){C(CN)C(d+)CPhꢁC(CN)2}(dppm-P)Cp* D, is discussed. Only the h1-dienyl
complex 7 is obtained from Ru(CꢀCPh)(dppe)Cp* and TCNE. © 2002 Published by Elsevier Science B.V.
Keywords: Ruthenium; Alkynyl; Cycloaddition; TCNE
1. Introduction
ligand by CN migration is also found, while the elec-
tron-rich ruthenium centre allows coordination of a CN
group in the h2 mode. This paper describes a series of
products which we have obtained from similar reactions
of Ru(CꢀCPh)(PP)Cp* (PP=dppm 1, dppe 2), in
which the dppm ligand (but not dppe) becomes
monodentate and enters into further reaction with the
cyanocarbon. Part of this work has been communicated
previously [5].
Reactions of transition metal s-alkynyl complexes
with electron-deficient cyanocarbon alkenes afford s-
cyclobutenyl (A, Scheme 1), s-butadienyl (B) or h3-al-
lylic complexes (C), according to the nature of the
metal centre and its associated ligands [1]. Many studies
of this chemistry have been carried out using the
Ru(PR3)2Cp system: if the two tertiary phosphines are
present as a chelating diphosphine, then the last stage
of the transformation of the adducts is precluded [1b].
Further reactions of the cyanocarbon ligand are rare,
apparently being limited to hydrolysis or alcoholysis to
give hydroxy- or alkoxy-imine ligands [2], or addition
of a second MLn group to one of the CN groups,
sometimes with the formation of macrocyclic complexes
[3].
2. Results
The complex Ru(CꢀCPh)(dppm)Cp* (1) was made in
80% yield by reaction of RuCl(dppm)Cp* with
HCꢀCPh, using NaOEt in EtOH as the base. It was
identified by elemental microanalysis and spectroscopi-
cally. The IR spectrum contains a strong w(CꢀC) band
We have recently described reactions of complexes
containing the more electron-rich Ru(PPh3)2Cp* frag-
ment, in which ready loss of one or both PPh3 ligands
occurs [4]. Isomerisation of the initial polycyanocarbon
1
at 2072 cm−1 and the H-NMR spectrum contains a
Cp* triplet at l 2.01 (by long-range coupling to phos-
phorus) with the dppm CH2 and Ph resonances at l
4.37 and between 6.94 and 7.83, respectively. The dppe
analogue 2 has been described before [6].
* Corresponding author. Tel.: +61-8-8303-5939; fax: +61-8-8303-
4358.
The reaction between
1 and tetracyanoethene,
E-mail address: michael.bruce@adelaide.edu.au (M.I. Bruce).
C2(CN)4 (TCNE), when carried out in a polar solvent
0022-328X/02/$ - see front matter © 2002 Published by Elsevier Science B.V.
PII: S0022-328X(02)01202-0

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M.I. Bruce et al. / Journal of Organometallic Chemistry 650 (2002) 141–150
such as THF, gives a product mixture from which the
anticipated butadienyl derivative Ru{C[CPhꢁC(CN)2]ꢁ
C(CN)2}(dppm)Cp* (3, Scheme 2) could be isolated as
dark red crystals in 20% yield. The structure has been
confirmed by a single-crystal X-ray determination (see
below) and spectroscopic data are consistent with the
solid state structure. The IR spectrum contains w(CN)
at 2217 cm−1 and the electrospray (ES) mass spectrum
of a solution containing NaOMe contains [M+Na]+,
[M+H]+ and [M−CN]+ ions. During purification by
preparative TLC, we noticed that the second band
changed colour, and in solution the change occurs too
rapidly to allow the NMR spectrum to be obtained.
Eventually repeated TLC enabled pure samples of com-
plexes 5 and 6 (see below) to be obtained, in 31 and 8%
yields, respectively. The latter complex is also formed
when solid 3 or its solutions are left standing in air or
when 3 is adsorbed on silica gel.
If the reaction between 1 and TCNE is carried out in
benzene, two orange complexes identified as Ru{h3-
C(CN)2CPhCꢁC(CN)2}(dppm-P)Cp* (4, 42%), con-
taining monodentate dppm, and Ru{h3-C(CN)2CPhCꢁ
C(CN)2}(dppmO)Cp* (5, 2.2%), containing the mono-
oxidised ligand PPh2CH2P(O)Ph2 (dppmO), were iso-
lated and identified by X-ray structure determinations.
Complex 4 was also obtained from the reaction in THF
Scheme 1.
Scheme 2.

M.I. Bruce et al. / Journal of Organometallic Chemistry 650 (2002) 141–150
143
Scheme 3.
earlier [5]. The IR spectrum contains three w(CN) bands
at 2218, 2157 and 2070 cm−1, while the ES mass
spectrum shows [M+H]+ and [M−CN]+ ions at m/z
851 and 824, respectively. The Me groups appear as a
in 31% yield. The IR spectra of 4 and 5 contain w(CN)
at 2217 and 2216 cm−1, respectively, while that of 4 has
w(PO) at 1200 cm−1. The Me resonance is a doublet at
l 1.26 for 4, indicating coupling to only one of the two
31P nuclei, while for 5, a singlet is found at l 1.48. The
dppm–CH2 multiplets are at l 3.26 (for 4) and 3.38,
3.51 (for 5). The 31P-NMR spectra are informative,
with two doublets at l −18.5 and 39.1 for the free and
coordinated PPh2 groups in 4, and at l 26.0 and 41.9
for the PꢁO and PꢂRu nuclei in 5. The ES mass spectra
contain [M+H]+ and [M−dppm]+ or [M−dppmO]+
ions.
1
doublet at l 1.60 in the H-NMR spectrum and the
CH2 multiplets are unusually well separated at l 3.24
and 5.40. A plethora of peaks in the 13C-NMR spec-
trum includes those for the Cp* group at l 9.42 and
99.90, the CH2 group as a double doublet at l 30.09,
and three equal intensity singlets for the CN groups at
l 114.87, 116.14, 122.58. The carbon chain gives rise to
singlets at l 125.33 and 126.43 [C(3) and C(4), not
assigned individually], that for C(2) being within the Ph
multiplet between l 127.92 and 135.85. The Ru-bonded
C(1) and CN carbons are considerably deshielded at l
153.22 and 179.96, respectively, and exhibit CP cou-
plings of 18.86 and 19.16 Hz, respectively.
We have studied the effect of increasing the bite
angle of the chelating diphosphine by examining similar
reactions of Ru(CꢀCPh)(dppe)Cp* (2). The reaction of
TCNE with 2 in THF gives the expected butadienyl
derivative Ru{C[CPhꢁC(CN)2]ꢁC(CN)2}(dppe)Cp* (7),
which is stable in solution, no doubt a result of the
increased stability of the five-membered chelate
Ru(dppe) system. The identity of 7 was also confirmed
by an X-ray structure determination: the ES mass
spectrum has M+ at m/z 865. The IR spectrum con-
tained w(CN) bands at 2206 and 2198 cm−1, while the
1H-NMR spectrum has resonances for the Me groups
at l 0.96 and multiplets for the dppe–CH2 groups at l
2.00, 2.34 and 2.76. The 31P-NMR spectrum contains
only a doublet at l 48.47.
The smaller bite angle of the dppm ligand results in
ring strain which is eased by ready dissociation of one
of the P atoms from the ruthenium centre. This allows
the cyanocarbon ligand to take up the familiar h3-al-
lylic form, with its short RuꢂC(2) distance which corre-
sponds to
a carbenic form or zwitterion. The
monodentate dppm is air-sensitive, some of 4 being
converted to 5 by addition of oxygen to the uncoordi-
nated P atom to give the phosphine oxide.
As mentioned, complex 3 is very reactive, changing
to purple during chromatography, upon standing in
solution (CH2Cl2) or in the solid state in air. We found
that the same product was formed, together with some
intractable decomposition product, by heating 4 in
refluxing benzene for 36 h. It could be isolated in 73%
yield by preparative TLC as dark red crystals. These
were shown to be the cyanoruthenium complex
Ru(CN){C(CN)ꢁC[CPhꢁC(CN)2]PPh2CH2PPh2}Cp*
(6, Scheme 3), the structure of which has been reported

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M.I. Bruce et al. / Journal of Organometallic Chemistry 650 (2002) 141–150
2.1. Molecular structures
in Figs. 1–5, with selected bond parameters collected in
Table 1. While 1 is a benzene hemi-solvate, the others
Plots of single molecules of 1, 3–5 and 7 are shown
were all modelled as variously solvated with
Fig. 1. Plot of a molecule of Ru(CꢀCPh)(dppm)Cp* (1), showing atom numbering scheme.
Fig. 2. Plot of a molecule of Ru{C[ꢁC(CN)2]CPhꢁC(CN)2}(dppm)Cp* (3) showing atom numbering scheme.

M.I. Bruce et al. / Journal of Organometallic Chemistry 650 (2002) 141–150
145
Fig. 3. Plot of a molecule of Ru{C[ꢁC(CN)2]CPhꢁC(CN)2}(dppe)Cp* (7) showing atom numbering scheme.
Fig. 4. Plot of a molecule of Ru{h3-C(CN)2CPhCꢁC(CN)2}(dppm-P)Cp* (4) showing atom numbering scheme.
,
The RuꢂC(sp) distance in 1 [2.017(2) A] is identical
with that found in Ru(CꢀCPh)(PPh3)2Cp, while the
CꢀC separations are also experimentally the same
dichloromethane. Common to all are the Cp* groups,
which have average RuꢂC(Cp*) distances between 2.25
,
and 2.30 A, the ranges of individual values being
,
,
[1.217(3) and 1.204(5) A, respectively] [7]. The
between 2.214(2) and 2.326(2) A. Comparison of the
2
,
RuꢂP distances in 3 and 7 show the smaller bite angle
of the dppm ligand [71.28(3) vs. 81.90(9) for dppe] has
RuꢂC(sp ) distances in 3 and 7 [2.106(2), 2.090(9) A]
,
are ca. 0.09 A longer than the RuꢂC(sp) separations, as
,
no effect on the RuꢂP distances [2.32(2) vs. 2.341(3) A].
expected. Average CꢂCN and CꢂN distances in all
,
The increased ring strain in 3 is accommodated around
the RuPCP ring, all intraring angles being noticeably
smaller than those found in 7.
complexes are constant, at 1.44 and 1.14 A,
respectively.
In 4 and 5, conversion of the butadienyl into the

146
M.I. Bruce et al. / Journal of Organometallic Chemistry 650 (2002) 141–150
h3-allylic ligand has occurred, with the dppm in 4
becoming monodentate. The cyanocarbon ligand has
almost equal CꢂC distances within the coordinated C3
unit, although the RuꢂC distances are significantly dif-
ferent. The ‘p-bonded’ C(1)ꢂC(2) fragments in 4 [5] are
ment to the metal [5]. Concomitant cleavage of a RuꢂC
bond then generates an electron-deficient centre at C(2),
as in D (Scheme 3). Isomerisation of the cyanocarbon
occurs by migration of the CN group from the metal to
C(2), the resulting vacant co-ordination site then being
filled by an electron-donor ligand, such as an h2-CN
group or a CN group from a second molecule of
complex. A third type of reaction is that proposed here,
whereby the free arm of the dppm ligand (as found in
4) intramolecularly attacks C(2) to give ylid complex 6,
the cyano group remaining attached to the metal
centre.
The smaller bite angle of the dppm ligand results in
some degree of ring strain which is relieved by ready
dissociation of one of the P atoms from the ruthenium
centre. This allows the cyanocarbon ligand to take up
the familiar h3-allylic form, with its short RuꢂC(3)
distance which corresponds to a carbenic form or zwit-
terion. Complex 4 with monodentate dppm is air-sensi-
tive, being converted to the analogous dppmO
derivative 5 on standing in air, by addition of oxygen to
the uncoordinated phosphorus atom.
,
,
2.206(2) [2.218(2)] and 2.175(2) A [2.158(2) A] distant
from the metal, while the short RuꢂC(3) distances
,
(1.985(2) [1.983(2) A]) are consistent with a degree of
multiple bonding which can be rationalised in terms of
a contribution from the zwitterionic form (C, Scheme
1).
Oxidation of the non-coordinated phosphorus centre
in 6 has little effect on the molecular structure. Com-
plexes 4 and 5 differ only by addition of an oxygen
,
atom to P(2) in the latter [P(2)ꢂO 1.489(1) A]. Other
distances and angles in the two complexes are similar
except for the shortening of P(2)ꢂC(0) in 5 [1.879(2) in
,
4 vs. 1.834(2) A in 5].
3. Discussion
While similar complexes containing Cp ligands have
been found not to undergo further reaction, the same is
not true for the Cp* derivatives. We have surmised that
this increased reactivity is due to the increased electron
density at the ruthenium centre, which in other exam-
ples has allowed the formation of h2-CN groups, as
well as encouraging isomerisation by CN group migra-
tion [5]. We have previously suggested that a possible
route to the cyano-ruthenium complexes might be mi-
gration of a CN group from a dicyanomethylene frag-
4. Conclusions
We have shown that the reactivity of s-bonded
cyanocarbon ligands is considerably enhanced when Cp
is replaced by the more strongly electron-donating Cp*
ligand. While not surprising, the resulting chemistry has
revealed novel examples of C(sp2)ꢂCN bond cleavage,
Fig. 5. Plot of a molecule of Ru{h3-C(CN)2CPhCꢁC(CN)2}(dppmO)Cp* (5) showing atom numbering scheme.

M.I. Bruce et al. / Journal of Organometallic Chemistry 650 (2002) 141–150
147
Table 1
Selected bond lengths (A) and bond angles (°) for 1, 3–5 and 7
,
1
3
4
5
7
Bond lengths
RuꢂP(1)
RuꢂP(2)
RuꢂC(Cp*)
(av.)
2.2679(8)
2.2735(6)
2.220(4)–2.272(6)
2.25(2)
2.3356(7)
2.3071(6)
2.255(3)–2.300(2)
2.28(3)
2.3939(6)
–
2.214–2.308(2)
2.26(4)
2.3935(6)
2.379(3)
2.303(2)
2.23–2.32(1)
2.30(4)
2.214–2.326(2)
2.26(5)
RuꢂC(100)
RuꢂC(1)
RuꢂC(2)
1.892
2.017(2)
–
–
1.217(3)
–
1.436(3)
–
–
1.918
–
–
1.899
1.905
1.937
–
–
2.090(9)
1.37(1)
1.51(1)
1.46(2)
1.39(1)
2.206(2)
2.175(2)
1.985(2)
1.473(2)
1.427(2)
1.491(3)
1.362(2)
1.433–1.455(2)
1.844(2)
1.879(2)
2.218(2)
2.158(2)
1.983(2)
1.479(2)
1.432(3)
1.489(3)
1.360(3)
1.434–1.450(3)
1.851(2)
1.834(2)
RuꢂC(3)
2.106(2)
1.364(3)
1.490(3)
1.491(4)
1.377(3)
1.438–1.443(4)
1.845(2)
1.840(3)
C(1)ꢂC(2)
C(2)ꢂC(3)
C(2)ꢂC(21)
C(3)ꢂC(4)
C(1,4)ꢂCN (range)
P(1)ꢂC(0)
P(2)ꢂC(0)
1.42–1.47(1)
1.81(1) [C(10)]
1.865(9) [C(20)]
1.855(2)
1.850(3)
Bond angles
C(100)ꢂRuꢂP(1)
C(100)ꢂRuꢂP(2)
C(100)ꢂRuꢂC(1)
C(100)ꢂRuꢂC(2)
C(100)ꢂRuꢂC(3)
P(1)ꢂRuꢂP(2)
P(1)ꢂRuꢂC(1)
P(1)ꢂRuꢂC(2)
P(1)ꢂRuꢂC(3)
P(2)ꢂRuꢂC(1)
P(2)ꢂRuꢂC(3)
C(1)ꢂRuꢂC(3)
RuꢂP(1)ꢂC(0)
RuꢂP(2)ꢂC(0)
P(1)ꢂC(0)ꢂP(2)
RuꢂC(1)ꢂC(2)
RuꢂC(3)ꢂC(4)
C(1)ꢂC(2)ꢂC(3)
C(2)ꢂC(3)ꢂC(4)
C(21)ꢂC(2)ꢂC(1)
C(21)ꢂC(2)ꢂC(3)
137.8
139.3
–
–
133.6
125.5
–
–
123.1
70.97(2)
–
120.5
–
132.6
129.6
135.5
–
92.38(5)
109.91(5)
89.27(5)
–
119.6
–
133.3
127.2
133.9
–
93.37(5)
113.15(6)
91.45(6)
–
130.3
126.4
–
–
120.1
81.90(9)
–
–
91.8(3)
–
95.3(3)
–
108.8(3) [C(20)]
109.6(3) [C(10)]
–
71.28(3)
81.53(9)
–
–
80.04(7)
–
–
96.2(1)
96.11(7)
91.2(1)
175.2(2)
–
–
–
–
89.27(7)
99.99(6)
–
95.61(8)
96.72(7)
94.0(1)
–
–
–
70.80(6)
114.21(6)
70.20(8)
114.12(6)
119.7(1)
69.2(1)
124.2(1)
68.1(1)
–
–
125.4(7)
127(1)
110.4(8)
116.2(9)
116.7(9)
120.7(2)
110.7(2)
117.9(2)
120.6(2)
114.1(1)
133.6(2)
123.6(1)
122.3(1)
112.7(2)
133.4(2)
124.3(2)
123.0(2)
174.7(2)
–
Torsion/dihedral angles
C(1)ꢂC(2)ꢂC(3)ꢂC(4)
–
−79.9(3)
141.5(2)
136.6(2)
−76(1)
In 1, Cp* parameters refer to the major component; for all compounds C(100) is the Cp* ring centroid. Additional data: For 5: P(2)ꢂO(2) 1.489(1)
,
,
A; C(0)ꢂP(2)ꢂO(92) 117.61(9)°. For 7: C(10)ꢂC(20) 1.53(1) A; P(1)ꢂC(10)ꢂC(20) 110.8(6), P(2)ꢂC(20)ꢂC(10) 108.0(7)°.
which may be related to the recently reported conver-
sion (by an intramolecular oxidative addition reaction)
of Ni(h2-NCPh)(dippe) to Ni(CN)(Ph)(dippe) [8]. With
PPh3 complexes, facile loss of one phosphorus ligand
allows its replacement by an N-bonded cyanocarbon
from a second molecule of complex. In the case of
dppm, in contrast, the free phosphorus is tethered by
the CH2 group and is able to attack a positively-charged
carbon of the alkenyl ligand to give 7. The reactions
described above and earlier provide a route for modify-
ing cyanocarbon ligands attached to electron-rich tran-
sition metals.
5. Experimental
5.1. General reaction conditions
Reactions were carried out under an atmosphere of
nitrogen, 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 Microanalyt-
ical Service, Delta, B.C., Canada. Preparative TLC was
carried out on glass plates (20×20 cm) coated with
silica gel (Merck 60 GF254, 0.5 mm thickness).

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M.I. Bruce et al. / Journal of Organometallic Chemistry 650 (2002) 141–150
5.1.1. Instrumentation
5.1.5. (b) In benzene
IR: Perkin–Elmer 1720X FTIR. 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) spectrometers. Unless otherwise stated,
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 [9].
TCNE (60 mg, 0.48 mmol) was added to a solution
of Ru(CꢀCPh)(dppm)Cp* (170 mg, 0.24 mmol) in ben-
zene (10 ml). After stirring overnight at r.t., the mixture
had become dark brown with a black precipitate. The
latter was filtered off, the filtrate was evaporated and
the residue dissolved in CH2Cl2 and separated by
preparative TLC (acetone–hexane 3/7) into two
fractions.
Band 1 (Rf 0.49) gave orange crystals (CH2Cl2) of
Ru{h3-C(CN)2CPhCꢁC(CN)2}(dppm-P)Cp* (4) (85
mg, 42.5%). Anal. Found: C, 68.80; H, 5.16; N, 6.75.
Calc. for C49H42N4P2Ru: C, 69.25; H, 4.98; N, 6.59%;
M, 850. IR (CH2Cl2): w(CN) 2217s; other bands at
5.1.2. Reagents
The complexes RuCl(dppm)Cp* [4] and Ru(CꢀCPh)-
(dppe)Cp* [6] were obtained as previously described.
TCNE (Aldrich) was sublimed before use.
1
1589m, 1572s, 1482m, 1434s, 1379m cm−1. H-NMR
4
5.1.3. Preparation of Ru(CꢀCPh)(dppm)Cp* (1)
(CDCl3): l 1.26 [d, J(HP) 1.0, 15H, Cp*], 3.26 (m, 2H,
A solution of RuCl(dppm)Cp* (140 mg, 0.2 mmol)
and HCꢀCPh (65 mg, 0.6 mmol) in EtOH (15 ml) was
heated at reflux point for 2 h. After cooling to room
temperature (r.t.), a solution of NaOEt [from sodium
(40 mg-atom) in EtOH (1 ml)] was added dropwise to
the reaction mixture. Cooling in an ice-bath for 10 min
resulted in deposition of a yellow precipitate, which was
filtered and washed with cold EtOH to give
Ru(CꢀCPh)(dppm)Cp* (1) (120 mg, 80%) as yellow
crystals (benzene–hexane). Anal. Found: C, 70.83; H,
5.75. Calc. for C43H42P2Ru: C, 71.55; H, 5.87%. IR
(CH2Cl2): w(CꢀC) 2072s cm−1. 1H-NMR (C6D6): l 2.01
[t, 4J(HP) 1.8, 15H, Cp*], 4.37 (m, 2H, CH2), 6.94–7.83
(m, 25H, Ph). 31P-NMR (C6D6): l 18.21 (s, dppm).
PCH2), 6.99–8.19 (m, 25H, Ph). 31P-NMR (CDCl3): l
−18.50 [d, J(PP) 30.6, PPh2], 39.11 [d, J(PP) 30.6,
RuꢂPPh2]. ES mass spectrum (MeOH, m/z): 850, M+;
466, [M−dppm]+.
Band 2 (Rf 0.09) afforded orange crystals (CH2Cl2–
MeOH) of Ru{h3-C(CN)2CPhCꢁC(CN)2}(dppmO)Cp*
(5) (4.5 mg, 2.2%). Found: C, 66.86; H, 4.88; N, 6.19.
Calc. for C49H42N4OP2Ru: C, 67.89; H, 4.84; N, 6.47%;
M, 866. IR (CH2Cl2): w(CN) 2216s, w(PO) 1200m; other
bands at 1605m, 1571s, 1492m, 1437s, 1379m cm−1
.
1H-NMR (CDCl3): l 1.48 (s, 15H, Cp*), 3.38, 3.51
(2×s, CH2); 7.16–7.47 (m, 25H, Ph). 31P-NMR
(CDCl3): l 26.03 [d, J(PP) 31.9, P(O)], 41.9 [d, J(PP)
31.9, RuꢂP]. ES mass spectrum (MeOH containing
NaOMe, m/z): 889, [M+Na]+; 867, [M+H]+; 466,
[M−dppmO]+.
5.1.4. Reactions between Ru(CꢀCPh)(dppm)Cp* and
TCNE. (a) In THF
A mixture of Ru(CꢀCPh)(dppm)Cp* (290 mg, 0.4
mmol) and TCNE (154 mg, 1.2 mmol) in THF (25 ml)
was stirred overnight at r.t. After evaporation of sol-
vent, the residue was extracted with CH2Cl2 and sepa-
rated by preparative TLC (acetone–hexane 3/7) into
two fractions.
5.1.6. Thermolysis of
Ru{p3-C(CN)2CPhCꢁC(CN)2}(dppm-P)Cp* (4)
Only one product is formed if Ru{h3-
C(CN)2CPhCꢁC(CN)2}(dppm-P)Cp* (4) (75 mg, 0.09
mmol) is heated in refluxing benzene (7 ml) for 36 h.
Purification by preparative TLC gave a dark purple
band (Rf 0.17) which afforded dark red crystals (ben-
The orange band (Rf 0.49) contained 5 (104.3 mg,
31%). A cherry-red band (Rf 0.40) gave dark red crys-
zene–hexane)
of
tals
(CH2Cl2–MeOH)
of
Ru(CN){C(CN)C[CPhꢁC(CN)2]PPh2CH2PPh2}Cp* (6)
(55 mg, 73%). Anal. Found: C, 68.06; H, 5.15; N, 6.03.
Calc. for C49H42N4P2Ru: C, 69.25; H, 4.98; N, 6.59%;
M, 850. IR (CH2Cl2): w(CN) 2218m, 2157w, 2070m;
Ru{C[ꢁC(CN)2]CPhꢁC(CN)2}(dppm)Cp* (3) (67.4 mg,
20%). IR (nujol): w(CN) 2217m, 2194m; other bands at
1575m, 1539m, 1471m, 1434s cm−1. ES mass spectrum
(MeOH containing NaOMe, m/z): 873, [M+Na]+;
851, [M+H]+ 824, [M−CN]+.
During development, the second band above gradu-
ally developed dark purple steaks, which was further
purified to give a dark purple band (Rf 0.17) which
contained
Ru(CN){C(CN)C[CPhꢁC(CN)2]PPh2CH2PPh2}Cp* (6)
(27.2 mg, 8%). Complex 6 is formed when solutions of
3 in CH2Cl2 are left to stand, when 3 is adsorbed on
silica gel, or when solid 3 is kept in air (the latter
process is accompanied by some decomposition).
other bands at 1601s, 1478m, 1436s, 1302w cm−1
.
4
1H-NMR (CDCl3): l 1.60 [d, J(HP) 1.6, 15H, Cp*],
3.24, 5.40 (2×m, 2×1H, CH2), 6.64–7.76 (m, 25H,
Ph). 13C-NMR (CDCl3): l 9.42 (s, Me), 30.09 [dd,
J(CP) 48, 37, CH2], 99.90 (s, Cp*), 114.87 [s, C(5)N],
116.14 [s, C(6)N], 122.58 [s, C(8)N], 125.33 [s, C(3)],
126.43 [s, C(4)], 127.92–135.85 (m, Ph+C(2)], 153.22
[d, J(CP) 18.86, C(1)], 179.96 [d, J(CP) 19.16, [C(7)N].
31P-NMR (CDCl3): l 13.87 (s, PꢂC), 58.61 (s, RuꢂP).
ES mass spectrum (MeOH, m/z): 851, [M+H]+; 824,
[M−CN]+; 621, [Ru(dppm)Cp*]+.

M.I. Bruce et al. / Journal of Organometallic Chemistry 650 (2002) 141–150
149
5.1.7. Reaction of Ru(CꢀCPh)(dppe)Cp* (2) with
TCNE
tion with proprietary software, No with F\4|(F) being
used in the full-matrix least-squares refinement. All
data were measured using monochromatic Mo–Ka ra-
A mixture of Ru(CꢀCPh)(dppe)Cp* (100 mg, 0.136
mmol) and TCNE (52 mg, 0.406 mmol) in THF (10 ml)
was stirred at r.t. for 4 h when all starting ruthenium
complex had been consumed. Removal of THF, extrac-
tion of the residue with CH2Cl2 and separation by
preparative TLC (acetone–hexane 3/7) gave a bright
yellow baseline, which could not be investigated fur-
ther, and a red band (Rf 0.38). The latter afforded dark
red crystals (CH2Cl2–MeOH) of Ru{C[ꢁC(CN)2]CPhꢁ
C(CN)2}(dppe)Cp* (7) (60.3 mg, 51%). Found: C,
66.39; H, 5.02; N, 6.03. Calc. for C50H44N4P2Ru)·
0.5CH2Cl2: C, 66.88; H, 4.97; N, 6.18%; M, 865. IR
(CH2Cl2): w(CN) 2206m, 2198m; other bands at 1606w,
,
diation, u=0.71073 A. Anisotropic thermal parameter
forms were refined for the non-hydrogen atoms, (x, y,
z, Uiso)H being constrained at estimated values. Conven-
tional residuals R, Rw on ꢀFꢀ are given [weights:
(|2(F)+0.0004F2)−1]. Neutral atom complex scatter-
ing factors were used; computation used the XTAL 3.4
program system [10]. Pertinent results are given in the
Figures (which show non-hydrogen atoms with 50%
probability amplitude displacement ellipsoids and hy-
,
drogen atoms with arbitrary radii of 0.1 A) and Tables
1 and 2, individual variations, difficulties, etc., being
noted.
1
1518m, 1486m, 1434s cm−1. H-NMR (CDCl3): l 0.96
(s, 15H, Cp*), 2.00 (m, 2H, CH2), 2.34, 2.76 (2×m,
2×1H, CH2), 6.10–7.87 (m, 25H, Ph). 31P-NMR
(CDCl3): l 48.47 [d, J(PP) 13, PPh2), 77.30 [d, J(PP)
13, PPh2]. ES mass spectrum (CH2Cl2–MeOH, m/z):
865, M+.
5.2.1. Variata
1. The Cp* ligand is rotationally disordered about
the Ru-centroid axis, major and minor components
refining to occupancies x=0.718(3), 1−x, with the
methyl substituents of the minor component quasi-sym-
metrically disposed between those of the major compo-
nent, which is depicted in Fig. 1.
Complex 7 slowly decomposes in air to give purple
and green solids.
2. Difference map residues were modelled in terms of
a pair of 0.25 weighted CH2Cl2 moieties disposed about
a crystallographic 2-axis.
5.2. Structure determinations
Full spheres of diffraction data were measured at ca.
153 K using a Bruker AXS CCD area-detector instru-
ment. Ntotal reflections were merged to N unique (Rint
quoted) after ‘empirical’ multiscan absorption correc-
4. All hydrogen atoms were refined in (x, y, z, Uiso).
5. Difference map residues were modelled in terms of
a pair of CH2Cl2 moieties, occupancies refining to
0.371(2), 0.265(2).
Table 2
Crystal data and refinement details for 1, 3–5 and 7
Compound
1
3
4
5
7
Empirical formula
C43H42P2Ru·0.5C6H C49H42N4P2Ru·0.5CH2C C49H42N4P2Ru·CH2CC49H42N4OP2Ru·0.64CH2C C50H44N4P2Ru·0.5CH2C
l2
l2
l2
l2
6
Formula weight
Crystal system
Space group
760.9
892.4
Monoclinic
934.9
Triclinic
920.3
Triclinic
906.4
Monoclinic
C2/c
34.392(5)
11.391(1)
22.572(2)
Monoclinic
C2/c (C62h, No. 15) C2/c
P1 (Ci , No. 2)
P1
1
(
(
,
a (A)
31.560(1)
16.5455(8)
17.2744(8)
36.101(2)
12.8567(8)
19.546(2)
11.845(2)
11.935(2)
17.677(3)
94.017(2)
108.986(2)
105.567(2)
2242
10.068(1)
15.242(2)
15.535(2)
96.438(2)
99.673(2)
106.123(2)
2226
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
121.548(1)
107.054(2)
107.004(3)
3
,
V (A )
Z
7687
8
1.315
5.2
8673
8
1.367
5.4
8456
8
1.424
5.5
2
2
Dcalc (g cm−3
)
1.385
5.8
1.373
5.4
v (cm−1
)
Crystal size (mm)
Tmax/min
2qmax (°)
Ntot
0.37×0.14×0.08
0.73, 0.86
75
0.35×0.14×0.12
0.70, 0.83
75
0.45×0.38×0.32
0.77, 0.87
58
0.45×0.45×0.16
0.72, 0.80
58
0.15×0.12×0.10
0.59, 0.84
50
79862
76313
21979
21273
25116
Nr (Rint
No
)
20178 (0.068)
11287
21492 (0.069)
11969
10873 (0.018)
9391
10582 (0.013)
9526
7431 (0.012)
4173
R
0.046
0.049
0.028
0.031
0.069
Rw
0.048
1.6(1)
0.050
1.9(1)
0.035
0.58(4)
0.039
0.96(3)
0.077
2.9(3)
3
,
ꢀDzmaxꢀ (e A )

150
M.I. Bruce et al. / Journal of Organometallic Chemistry 650 (2002) 141–150
(c) M.I. Bruce, P.A. Humphrey, M.R. Snow, E.R.T. Tiekink, J.
6. Supplementary material
Organomet. Chem. 303 (1986) 417;
(d) M.I. Bruce, D.N. Duffy, M.J. Liddell, M.R. Snow, E.R.T.
Tiekink, J. Organomet. Chem. 335 (1987) 365;
(e) M.I. Bruce, M.J. Liddell, M.R. Snow, E.R.T. Tiekink,
Organometallics 7 (1988) 343;
(f) M.I. Bruce, M.P. Cifuentes, M.R. Snow, E.R.T. Tiekink, J.
Organomet. Chem. 359 (1989) 379;
Crystallographic data for the structure determina-
tions have been deposited with the Cambridge Crystal-
lographic Data Centre, CCDC nos. 174607–174611 for
compounds 1, 3, 4, 5 and 7, respectively. Copies of this
information may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge CB2
1EZ, UK (Fax: +44-1223-336033; e-mail: deposit@
ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
(g) M.I. Bruce, T.W. Hambley, M.J. Liddell, M.R. Snow, A.G.
Swincer, E.R.T. Tiekink, Organometallics 9 (1990) 96.
[2] (a) M.I. Bruce, T.W. Hambley, M.J. Liddell, A.G. Swincer,
E.R.T. Tiekink, Organometallics 9 (1990) 2886;
(b) M.I. Bruce, M.E. Smith, B.W. Skelton, A.H. White, J.
Organomet. Chem. 637–639 (2001) 490.
[3] M.I. Bruce, P.J. Low, B.W. Skelton, A.H. White, New J. Chem.
22 (1998) 419.
[4] M.I. Bruce, B.C. Hall, B.W. Skelton, A.H. White, N.N. Zait-
seva, J. Chem. Soc. Dalton Trans. (2000) 2279.
[5] (a) M.I. Bruce, B.W. Skelton, A.H. White, N.N. Zaitseva, Inorg.
Chem. Commun. 4 (2001) 617;
(b) M.I. Bruce, B.W. Skelton, A.H. White, N.N. Zaitseva, J.
Chem. Soc. Dalton Trans. (2001) 3627.
[6] C. Bitcon, M.W. Whiteley, J. Organomet. Chem. 336 (1987) 385.
[7] (a) J.M. Wissner, T.J. Bartczak, J.A. Ibers, Inorg. Chim. Acta
100 (1985) 115;
Acknowledgements
This work was supported by the Australian Research
Council. We thank Professor Brian Nicholson (Univer-
sity of Waikato, New Zealand) for the mass spectra.
We are grateful to Johnson Matthey plc, Reading,
England, for a generous loan of RuCl3·xH2O.
(b) M.I. Bruce, M.G. Humphrey, M.R. Snow, E.R.T. Tiekink, J.
Organomet. Chem. 314 (1986) 213.
[8] J.J. Garcia, W.D. Jones, Organometallics 19 (2000) 5544.
[9] W. Henderson, J.S. McIndoe, B.K. Nicholson, P.J. Dyson, J.
Chem. Soc. Dalton Trans. (1998) 519.
[10] S.R. Hall, G.S.D. King, J.M. Stewart (Eds.), The XTAL 3.4
Users’ Manual, University of Western Australia, Lamb, Perth,
1995.
References
[1] (a) M.I. Bruce, T.W. Hambley, M.R. Snow, A.G. Swincer,
Organometallics 4 (1985) 494;
(b) M.I. Bruce, T.W. Hambley, M.R. Snow, A.G. Swincer,
Organometallics 4 (1985) 501;