Synthesis and reactivity of triruthenium carbonyl cluster complexes containing a bridging 1-azavinylidene ligand derived from benzophenone imine

Article abstract of DOI:10.1021/om9601662

The reaction of [Ru₃(CO)₁₂] with the lithium salt of benzophenone imine (LiN=CPh₂) followed by protonation with trifluoroacetic acid leads to the η¹-1-azavinylidene cluster complex [Ru₃(μ-H)(μ-N=CPh₂)(CO)₁₀] (1). Compound 1 cannot be prepared by direct reaction of [Ru₃(CO)₁₂] with benzophenone imine under thermal conditions. Carbonyl substitution and thermolysis reactions on compound 1 and on some of its derivatives are described. Complex 1 reacts with 1 and 2 equiv of bis(diphenylphosphino)methane (dppm) at room temperature to give the substituted derivatives [Ru₃(μ-H)(μ-N=CPh₂)(μ-dppm)(CO)₈] (2) and [Ru₃(μ-H)(μ-N=CPh₂)(μ-dppm)(dppm)(CO) ₇] (3), respectively. In both complexes the three bridging ligands span the same Ru-Ru edge; in addition, complex 3 contains an η¹-dppm ligand occupying an equatorial site on the unique Ru atom. An X-ray structure analysis of 3-0.5CH₂Cl₂ is reported. Thermolysis of complex 2 in THF at reflux temperature leads to [Ru₃(μ-H)(μ₃-N=CPh₂)(μ-dppm)(CO) ₇] (4), a compound which contains a bridging η²-1-azavinylidene ligand interacting with the three Ru atoms. Complex 4 reacts with CO (1 atm, 18 °C) reverting to complex 2. The reaction of compound 1 with PPh₃ at room temperature gives the monosubstituted derivative [Ru₃(μ-H)(μ-N=CPh₂)(PPh₃)(CO) ₉] (5), in which the P-donor ligand is attached to one of the two bridged Ru atoms. Thermolysis of 5 in THF at reflux temperature leads to [Ru₃(μ-H)(μ₃-N=CPh₂)(PPh ₃)(CO)₈] (6), which, as complex 4, contains a face-bridging η²-1-azavinylidene ligand. The reaction of complex 5 with PPh₃ occurs only at higher temperatures (40-70 °C) to give the asymmetrically disubstituted derivative [Ru₃(μ-H)(μ-N=CPh₂)(PPh₃) ₂(CO)₈] (7), which has the additional PPh₃ ligand attached to the unbridged Ru atom. Compound 7 is thermally unstable, undergoing an easy (40-70 °C) orthometalation reaction of a phenyl ring of the azavinylidene ligand to give the derivative [Ru₃(μ-H)₂(μ-N=CPhC₆H ₄)(PPh₃)₂(CO)₇] (8). This compound reacts with CO (1 atm, 18 °C) to regenerate complex 7.

Full text of DOI:10.1021/om9601662

3004
Organometallics 1996, 15, 3004-3010
Syn th esis a n d Rea ctivity of Tr ir u th en iu m Ca r bon yl
Clu ster Com p lexes Con ta in in g a Br id gin g
1-Aza vin ylid en e Liga n d Der ived fr om Ben zop h en on e
Im in e†
Pedro L. Andreu, J avier A. Cabeza,*,‡ Ignacio del R´ıo, and V´ıctor Riera
Instituto de Quı´mica Organometa´lica “Enrique Moles”, Facultad de Qu´ımica, Universidad de
Oviedo-CSIC, E-33071 Oviedo, Spain
Claudette Bois
Laboratoire de Chimie des Me´taux de Transition, Universite´ Pierre et Marie Curie,
URA-CNRS 419, 4 Place J ussieu, F-75252 Paris Cedex 05, France
Received March 5, 1996X
The reaction of [Ru3(CO)12] with the lithium salt of benzophenone imine (LiNdCPh2)
followed by protonation with trifluoroacetic acid leads to the η1-1-azavinylidene cluster
complex [Ru3(µ-H)(µ-NdCPh2)(CO)10] (1). Compound 1 cannot be prepared by direct reaction
of [Ru3(CO)12] with benzophenone imine under thermal conditions. Carbonyl substitution
and thermolysis reactions on compound 1 and on some of its derivatives are described.
Complex 1 reacts with 1 and 2 equiv of bis(diphenylphosphino)methane (dppm) at room
temperature to give the substituted derivatives [Ru3(µ-H)(µ-NdCPh2)(µ-dppm)(CO)8] (2) and
[Ru3(µ-H)(µ-NdCPh2)(µ-dppm)(dppm)(CO)7] (3), respectively. In both complexes the three
bridging ligands span the same Ru-Ru edge; in addition, complex 3 contains an η1-dppm
ligand occupying an equatorial site on the unique Ru atom. An X-ray structure analysis of
3‚0.5CH2Cl2 is reported. Thermolysis of complex 2 in THF at reflux temperature leads to
[Ru3(µ-H)(µ3-NdCPh2)(µ-dppm)(CO)7] (4), a compound which contains a bridging η2-1-
azavinylidene ligand interacting with the three Ru atoms. Complex 4 reacts with CO (1
atm, 18 °C) reverting to complex 2. The reaction of compound 1 with PPh3 at room
temperature gives the monosubstituted derivative [Ru3(µ-H)(µ-NdCPh2)(PPh3)(CO)9] (5), in
which the P-donor ligand is attached to one of the two bridged Ru atoms. Thermolysis of 5
in THF at reflux temperature leads to [Ru3(µ-H)(µ3-NdCPh2)(PPh3)(CO)8] (6), which, as
complex 4, contains a face-bridging η2-1-azavinylidene ligand. The reaction of complex 5
with PPh3 occurs only at higher temperatures (40-70 °C) to give the asymmetrically
disubstituted derivative [Ru3(µ-H)(µ-NdCPh2)(PPh3)2(CO)8] (7), which has the additional PPh3
ligand attached to the unbridged Ru atom. Compound 7 is thermally unstable, undergoing
an easy (40-70 °C) orthometalation reaction of a phenyl ring of the azavinylidene ligand to
give the derivative [Ru3(µ-H)2(µ-NdCPhC6H4)(PPh3)2(CO)7] (8). This compound reacts with
CO (1 atm, 18 °C) to regenerate complex 7.
In tr od u ction
development of its inorganic chemistry. In mononuclear
compounds, its coordination chemistry is represented
by Mo,3 W,3 Fe,4 Ru,5 Os,6-11 Rh,2 Ir,2,9 and Ni12
complexes corresponding to the coordination types
shown in Chart 1, which involve η1-terminal ligands (A,
B), η2-terminal ligands (C), and orthometalated ligand
derivatives (D, E). Binuclear complexes derived from
this ligand have only been reported for Mo,3 W,3 Fe,4
Rh,2 and Ir2 (F ) (Chart 1).
Most N-unsubstituted Schiff bases, HNdCR1R2, par-
ticularly those derived from all types of aldehydes or
from ketones with alkyl R groups, are very unstable at
room temperature. This low stability has been an
impediment to the study of their behavior as ligands.
In fact, in most cases, their metal complexes have been
prepared by reactions that modify coordinated ligands
(nitriles, oximes, azines, diazirines, diazepines, silyl-
and stannylimines, imido ligands, etc.) instead of using
N-unsubstituted imines as ligand precursors.1,2
(3) Farmery, K.; Kilner, M.; Midcalf, C. J . Chem. Soc. A 1970, 2279.
(4) Kilner, M.; Midcalf, C. J . Chem. Soc., Dalton Trans. 1974, 1620.
(5) Werner, H.; Daniel, T.; Braun, T.; Nu¨rnberg, O. J . Organomet.
Chem. 1993, 462, 309.
(6) Esteruelas, M. A.; Lahoz, F. J .; Lo´pez, A. M.; On˜ate, E.; Oro, L.
A. Organometallics 1995, 14, 2496.
Benzophenone imine has recently become commer-
cially available, and this has allowed a considerable
(7) Daniel, T.; Werner, H. J . Chem. Soc., Dalton Trans. 1994, 221.
(8) Werner, H.; Daniel, T.; Braun, T.; Nu¨rnberg, O. J . Organomet.
Chem. 1994, 480, 145.
(9) Daniel, T.; Muller, M.; Werner, H. Inorg. Chem. 1991, 30, 3118.
(10) Daniel, T.; Knaup, M.; Dziallas, M.; Werner, H. Chem. Ber.
1993, 126, 1981.
(11) Daniel, T.; Werner, H. Z. Naturforsch. B 1992, 47, 1707.
(12) Hoberg, H.; Go¨tz, V.; Kru¨ger, C.; Tsay, Y. H. J . Organomet.
Chem. 1979, 169, 209.
† Dedicated to Professor Rafael Uso´n on his 70th birthday.
‡ E-mail: jac@sauron.quimica.uniovi.es. Fax: +34 8 510 3446.
X Abstract published in Advance ACS Abstracts, J une 1, 1996.
(1) Mehrota, R. C. In Comprehensive Coordination Chemistry;
Wilkinson, G., Gillard, R. D., McCleverty, J . A., Eds.; Pergamon:
Oxford, U.K., 1987; Vol. 2, pp 279-281.
(2) Esteruelas, M. A.; Lahoz, F. J .; Oliva´n. M.; On˜ate, E.; Oro, L. A.
Organometallics 1994, 13, 3315.
S0276-7333(96)00166-5 CCC: $12.00 © 1996 American Chemical Society
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Triruthenium Carbonyl Cluster Complexes
Organometallics, Vol. 15, No. 13, 1996 3005
Ch a r t 1
Sch em e 1
Ch a r t 2
It should be noted that the N-donor ligands in
compounds of types B, F -H, and J can be regarded as
1-azavinylidene or alkylideneimido ligands.
We now report the synthesis of a new triruthenium
cluster, [Ru3(µ-H)(µ-NdCPh2)(CO)10] (1), which contains
an edge bridging η1-1-azavinylidene ligand derived from
benzophenone imine. The fact that compound 1 repre-
sents the first trinuclear transition metal cluster con-
taining a 1-azavinylidene ligand with a disubstituted
carbon atom, coupled to its air-stability and efficient
preparation (67% isolated yield, based on the amount
of starting [Ru3(CO)12]), led us to undertake a study of
its reactivity. We also report here that carbonyl sub-
stitution and thermolysis reactions on compound 1 and
on some of its derivatives have led not only to new
cluster complexes containing µ-η1-1-azavinylidene ligands
but also to an orthometalated µ-η2-1-azavinylidene
derivative and to two trinuclear compounds containing
a µ3-η2-1-azavinylidene ligand.
Resu lts a n d Discu ssion
In the case of transition metal carbonyl cluster
compounds, the only previous examples known to
contain N-unsubstituted imine-type ligands are alde-
hyde imine derivatives.13-21 Thus, compounds of type
G (Chart 2) have been prepared in low yields by treating
aromatic nitriles with [M3(CO)12] (M ) Ru, Os) in the
presence of carboxylic acids or molecular hydrogen.13-17
In a related reaction, insertion of trifluoroacetonitrile
into an Os-H bond of [Os3(µ-H)2(CO)10] gives the
isomeric compounds H and I (Chart 2).18-20 The iso-
meric face-bridged derivatives J and K, derived from
the reduction of acetonitrile on iron clusters, have also
been reported.21
Syn th esis of Com p ou n d 1. No reaction was ob-
served between [Ru3(CO)12] and benzophenone imine
(THF or toluene, reflux temperature, 2 h). However,
the lithium salt of benzophenone imine, LiNdCPh2,
reacted smoothly (THF, 18 °C, 2 h) with [Ru3(CO)12] to
give a very air-sensitive anionic derivative, [Ru3(µ-
NdCPh2)(µ-CO)3(CO)7]-, which was not isolated. The
structure proposed for this species in Scheme 1 is based
on the similarity of its IR spectrum with those of the
related anionic compounds [Ru3(µ-dmpz)(µ-CO)3(CO)7]-
(Hdmpz ) 3,5-dimethylpyrazole)22 and [Ru3(µ-Opy)(µ-
CO)3(CO)7]- (HOpy ) 2-pyridone),23 which also contain
3-electron donor ligands. The latter has been made by
a synthetic procedure analogous to that of the 1-azavi-
nylidene derivative and has been characterized by X-ray
diffraction methods. Protonation of [Ru3(µ-NdCPh2)-
(µ-CO)3(CO)7]- led to the neutral hydrido derivative
[Ru3(µ-H)(µ-NdCPh2)(CO)10] (1), which was isolated as
an orange, air-stable solid. Its most relevant IR and
NMR data are collected in Tables 1-3. The symmetric
structure (Cs) proposed for this compound in Scheme 1
is strongly supported by its 13C{1H} NMR spectrum
(Table 3), which shows six carbonyl resonances of the
(13) Lausarot, P. M.; Turini, M.; Vaglio, G. A.; Valle, M.; Tiripicchio,
A.; Tiripicchio-Camellini, M. T.; Garibaldi, P. J . Organomet. Chem.
1984, 273, 239.
(14) Lausarot, P. M.; Operti, L.; Vaglio, G. A.; Valle, M.; Tiripicchio,
A.; Tiripicchio-Camellini, M. T.; Garibaldi, P. Inorg. Chim. Acta 1986,
122, 103.
(15) Bernhardt, W.; Vahrenkamp, H. Angew. Chem., Int. Ed. Engl.
1984, 23, 381.
(16) Bernhardt, W.; von Schnering, C.; Vahrenkamp, H. Angew.
Chem., Int. Ed. Engl. 1986, 25, 279.
(17) Bernhardt, W.; Vahrenkamp, H. Z. Naturforsch. B 1988, 43,
643.
(18) Adams, R. D.; Katahira, D. A.; Yang, L. W. J . Organomet. Chem.
1981, 219, 85.
(19) Adams, R. D.; Katahira, D. A.; Yang, L. W. J . Organomet. Chem.
1981, 219, 241.
(20) Banford, J .; Dawoodi, Z.; Herick, K.; Mays, M. J . J . Chem. Soc.,
Chem. Commun. 1982, 554.
(21) Andrews, M. A.; van Burskirk, G.; Knobler, C. B.; Kaesz, H. D.
J . Am. Chem. Soc. 1979, 101, 7245.
(22) Cabeza, J . A.; Franco, R. J .; Riera, V.; Garc´ıa-Granda, S.; Van
der Maelen, J . F. Organometallics 1955, 14, 3342.
(23) Lugan, N.; Laurent, F.; Lavigne, G.; Newcomb, T. P.; Liimata,
E. W. Organometallics 1992, 11, 1351.
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3006 Organometallics, Vol. 15, No. 13, 1996
Andreu et al.
Ta ble 1. Selected IR Da ta
Sch em e 2
compd
ν(CO)/cm-1
1a
2100 (w), 2066 (vs), 2051 (s), 2023 (vs), 2011 (s),
2005 (s), 1990 (w)
2b
3b
4b
5b
2059 (s), 2006 (vs), 1994 (m), 1979 (s), 1943 (w)
2025 (m), 1991 (vs), 1974 (m), 1954 (vs), 1918 (w)
2038 (s), 2012 (vs), 1992 (w), 1970 (s), 1946 (w)
2081 (m), 2044 (s), 2009 (vs), 1984 (m), 1972 (w),
1956 (w)
2071 (m), 2035 (s), 2009 (vs), 1974 (m), 1948 (m)
2059 (m), 2019 (vs), 1989 (m), 1956 (m)
2071 (w), 2008 (vs), 1949 (m)
6b
7c
8b
a
b
In hexane. In THF. c In CH2Cl2.
Ta ble 2. Selected 1H a n d 31P {1H} NMR Da ta
compd
δ(µ-H)/ppma
δ(P)/ppma
1
-13.94 (s)
-12.89 (t) [14.1]
-12.76 (t) [13.1]
2b
3c
10.16 (s)
30.17 (dt) {44.4, 17.0}, 9.85 (d,
2 P) {17.0}, -25.50 (d) {44.4}
32.15 (s)
30.97 (s)
37.10 (s)
37.32 (d) {31.2}, 28.61 (d) {31.2}
32.42 (d) {29.7}, 31.41 (d) {29.7}
4d
5
-15.37 (t) [13.3]
-13.12 (d) [7.4]
halides, etc.) results in the formation of anionic deriva-
tives [Ru3(µ-X)(CO)10]- that can be subsequently pro-
tonated to give [Ru3(µ-H)(µ-X)(CO)10].24 We have re-
cently reported that protonation of the anionic cluster
[Ru3(µ-dmpz)(µ-CO)3(CO)7]- leads to the neutral cluster
[Ru3(µ-H)(µ-dmpz)(CO)10], a compound which, as occurs
with compound 1, cannot be prepared by direct reaction
of [Ru3(CO)12] with the neutral N-donor ligand precursor
and which is structurally analogous to compound 1.22
Interestingly, the most convenient route to the anionic
cluster [Ru3(µ-dmpz)(µ-CO)3(CO)7]- is to treat [Ru3(µ-
H)(µ-CO)(CO)10]- with 3,5-dimethylpyrazole,22 while the
anionic 1-azavinylidene derivative [Ru3(µ-NdCPh2)(µ-
CO)3(CO)7]- is best prepared from [Ru3(CO)12] and the
lithium salt of the bridging ligand (vide supra).
Some other ruthenium clusters containing bridging
1-azavinylidene ligands have been reported. They cor-
respond to the general formula [Ru3(µ-H)(µ-NdCHR)-
(CO)10] and are isostructural with complex 1, but they
all contain a hydrogen atom on the azavinylidene carbon
atom and have been made via hydrogenation reactions
of coordinated nitrile ligands.13-17 The structures of all
these triruthenium clusters derived from N-unsubsti-
tuted Schiff bases are quite different from those found
for clusters derived from N-substituted Schiff bases, in
which both the N and C imine atoms are coordinated
to the metals, as in compounds of types I and K (Chart
2).25
6e
7
-14.33 (d) [10.4]
-12.69 (dd) [5.5, 3.5]
-10.81 (dd) [8.0, 4.1],
-14.78 (dd) [12.1, 5.9]
8
a
Spectra were recorded in CDCl3; multiplicities are given in
parentheses; coupling constants (Hz) are given in brackets [J (H-
b
P)] or braces {J (P-P)}. δ(CH2) ) 3.63 (m, 1 H), 2.93 (m, 1 H).
c δ(CH2) ) 3.53 (m, 1 H), 2.72 (m, 1 H), 1.26 (t, J ) 7.0 Hz, 1 H),
d
0.91 (t, J ) 6.0 Hz, 1 H). δ(CH2) ) 3.57 (m, 1 H), 2.62 (m, 1 H).
e In CD2Cl2.
Ta ble 3. Selected 13C{1H} NMR Da ta
compd
δ(CO)/ppma
δ(NdC)/ppma
1b
207.7 (s), 204.8 (s), 201.8 (s, 2 C), 194.2
(s, 2 C), 193.8 (s, 2 C), 184.7 (s, 2 C)
210.3 (s, 2 C), 208.0 (m, 3 C), 199.5 (s, 3 C)
216.2 (m, 2 C), 210.0 (s, 3 C), 202.0 (s, 2 C)
205.0 (s, 3 C), 197.8 (m, 2 C), 195.2 (s, 2 C)
209.0 (s), 207.2 (d, 15.0), 206.9 (s), 202.9
(s), 197.3 (d, 5.1), 196.9 (s), 195.4
(d, 9.3), 194.3 (s), 188.3 (s)
182.4 (s)
2c
3d
4e
5f
178.4 (s)
175.8 (s)
144.6 (s)
178.1 (s)
6g
7h
8i
201.5 (s), 199.4 (s), 197.0 (d, 5.0), 196.4
(s), 195.6 (d, 6.1), 194.4 (s), 193.5 (s),
184.8 (d, 9.2)
215.3 (s), 215.2 (s), 212.1 (s), 212.3 (s),
207.9 (d, 6.0), 202.0 (s), 201.9 (s),
199.4 (d, 2.0)
205.3 (d, 7.4), 203.5 (s), 201.9 (d, 7.9),
200.6 (d, 6.0), 200.3 (d, 4.7), 199.3 (s),
190.0 (s)
145.6 (s)
177.5 (s)
182.0 (s)
aSpectra were recorded in CD2Cl2; multiplicities, J (C-P) cou-
pling constants (in Hz), and number of equivalent carbon atoms
Com p lexes Der ived fr om Com p ou n d 1 a n d Bis-
(d ip h en ylp h osp h in o)m eth a n e. The room-tempera-
ture reaction of complex 1 with 1 equiv of bis(diphen-
ylphosphino)methane (dppm) in THF led to the disub-
stituted derivative [Ru3(µ-H)(µ-NdCPh2)(µ-dppm)(CO)8]
(2), which was isolated in 85% yield. Its 31P{1H} NMR
b
(other than one) are given in parentheses. Other signals: 147.1
(s, 2 C, Cipso of NdCPh2), 132.7-126.0 (10 C). c Other signals:
146.9 (s, 2 C, Cipso of NdCPh2), 137.7-127.0 (34 C), 25.7 (t, 18.0
d
Hz, CH2 of dppm). Other signals: 147.2 (s, 2 C, Cipso of NdCPh2),
139.4-127.6 (58 C), 35.0 (m, CH2 of dppm), 23.7 (t, 17.6 Hz, CH2
of dppm). e Other signals: 151.0 (s, 2 C, Cipso of NdCPh2), 132.8-
126.1 (34 C), 27.9 (t, 22.0 Hz, CH2 of dppm). f Spectrum run at
215 K; other signals: 148.6 (s, Cipso of NdCPh), 145.1 (s, Cipso of
NdCPh), 135.2-127.2 (28 C). Spectrum run at 200 K; other
signals: 151.7 (s, Cipso of NdCPh), 150.2 (s, Cipso of NdCPh),
134.8-128.3 (28 C). Other signals: 148.5 (s, Cipso of NdCPh),
145.6 (s, Cipso of NdCPh), 137.5-127.8 (46 C). Other signals:
170.7 (s, Ru-C of C6H4), 160.7 (s, Cipso of C6H4), 137.8 (s, Cipso of
NdCPh), 140.2 (s, CH of C6H4), 134.5-125.6 (42 C), 124.4 (s, CH
of C6H4), 120.9 (s, CH of C6H4).
1
spectrum contains only one singlet, while its H NMR
g
proton spectrum shows the hydride resonance as a
triplet (Table 2), indicating that the three bridging
ligands span the same Ru-Ru edge (Cs symmetry), as
depicted in Scheme 2.
h
i
(24) See, for example: (a) Szostak, S.; Strouse, C. E.; Kaesz, H. D.
J . Organomet. Chem. 1980, 191, 243. (b) Mayr, A.; Lin, Y. C.; Boag,
N. M.; Kaesz, H. D. Inorg. Chem. 1982, 21, 1704. (c) Kampe, C. E.;
Boag, N. M.; Knobler, C. B.; Kaesz, H. D. Inorg. Chem. 1984, 23, 1390.
(d) Mayr, A.; Lin, Y. C.; Boag, N. M.; Kampe, C. E.; Knobler, C. B.;
Kaesz, H. D. Inorg. Chem. 1984, 23, 4640. (e) Lavigne, G.; Kaesz, H.
D. J . Am. Chem. Soc. 1984, 106, 4647. (f) Boag, N. M.; Sieber, W. J .;
Kampe, C. E.; Knobler, C. B.; Kaesz, H. D. J . Organomet. Chem. 1988,
355, 385.
expected intensities (1:1:2:2:2:2) accompanied by the
resonances of the bridging 1-azavinylidene ligand. The
structure of complex 1 also supports the structure
proposed for its anionic precursor [Ru3(µ-NdCPh2)(µ-
CO)3(CO)7]-.
Kaesz was the first to report that the attack of
(25) Bohle, D. S.; Breidt, V. F.; Powell, A. K.; Vahrenkamp, H. Chem.
Ber. 1992, 125, 1111.
[Ru3(CO)12] by anionic nucleophiles X- (amido groups,
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Triruthenium Carbonyl Cluster Complexes
Organometallics, Vol. 15, No. 13, 1996 3007
The mild conditions required for the formation of
compound 2 and the isolation of only one of the possible
isomers confirm that the 1-azavinylidene ligand has a
strong cis-labilization effect.26 Such a effect has been
previously observed in other ruthenium carbonyl clus-
ters containing bridging amido ligands,27-30 but recent
kinetic studies on carbonyl substitution reactions in
edge-bridged triruthenium carbonyl cluster complexes
have pointed out that the mechanism governing the cis-
substitution (associative)31 is different from that operat-
ing in mononuclear complexes (dissociative).26
The bis(dppm) derivative [Ru3(µ-H)(µ-NdCPh2)(µ-
dppm)(dppm)(CO)7] (3) was obtained in 92% yield when
2 equiv of dppm was allowed to react with complex 1.
Although the incorporation of two dppm ligands into the
cluster was clearly evidenced by its analytical and
spectroscopic data, its H, 31P, and 13C NMR spectra at
1
F igu r e 1. Structural plot of [Ru3(µ-H)(µ-NdCPh2)(µ-
dppm)(dppm)(CO)7] (3) in 3‚0.5CH2Cl2. Thermal ellipsoids
are drawn at the 30% probability level.
room temperature were deceptively simple, preventing
a convincing structural assignment. Thus, the hydride
ligand was observed as a triplet in the 1H NMR
spectrum (Table 2), three (and not four) resonances were
observed in the 31P{1H} NMR spectrum (a doublet at
-25.5 ppm indicated of the presence of a monocoordi-
nated dppm ligand), and only three (and not seven)
carbonyl resonances were observed in the 13C{1H} NMR
spectrum (Table 3). Lower temperature NMR measure-
ments resulted in complex spectral changes, indicating
that the simplicity of the room-temperature spectra is
due to fluxional processes. It is accepted that phosphine
substitution in carbonyl cluster compounds generally
results in a slowing down of the carbonyl fluxionality
as compared with that of their unsubstituted precur-
sors,30,32 but complex 1 proved to be stereochemically
rigid at room temperature (vide supra), whereas the
ligands of the substituted derivative 3 seem to be quite
mobile.
The structure depicted in Scheme 2 for compound 3
is based on an X-ray diffraction analysis. Figure 1
shows the atomic labeling scheme. A selection of bond
distances and angles is given in Table 4. The cluster
consists of an isosceles triangle of ruthenium atoms with
the shortest edge, Ru(1)-Ru(2), triply bridged by the
hydride, 1-azavinylidene, and dppm ligands. A mono-
coordinated dppm ligand is attached to the unique Ru(3)
atom in an equatorial position. The cluster shell is
completed by seven terminal CO ligands. While the
phosphorus atoms of the bridging dppm ligand are
almost coplanar with the metal triangle (dihedral angle
between the Ru3 and Ru(1)-Ru(2)-P(1)-P(2) planes
9.4°), the hydride and 1-azavinylidene ligands are
located to either sides of the Ru3 plane (dihedral angles
between this plane and the Ru(1)-Ru(2)-H(1) and
Ru(1)-Ru(2)-N(1) planes -75.1 and 75.7°, respec-
tively). The azavinylidene N(1)-C(9) bond distance,
1.28(2) Å, is consistent with a NdC double bond,2 and
the Ru(1), Ru(2), N(1), C(9), C(60), and C(70) atoms are
Ta ble 4. Selected Bon d Len gth s a n d Bon d An gles
in 3.0.5CH2Cl2
Bond Lengths (Å)
Ru(1)-Ru(2)
Ru(2)-Ru(3)
Ru(2)-N(1)
Ru(2)-P(2)
Ru(1)-C(1)
Ru(2)-C(3)
Ru(3)-C(5)
Ru(3)-C(7)
Ru(2)-H(1)
P(2)-C(8)
2.772(2)
2.827(2)
2.11(1)
2.342(4)
1.81(2)
1.86(2)
1.89(2)
1.79(2)
1.70(5)
1.87(2)
1.87(2)
Ru(1)-Ru(3)
Ru(1)-N(1)
Ru(1)-P(1)
Ru(3)-P(3)
Ru(1)-C(2)
Ru(2)-C(4)
Ru(3)-C(6)
Ru(1)-H(1)
P(1)-C(8)
2.838(2)
2.05(1)
2.352(5)
2.318(5)
1.83(2)
1.84(2)
1.86(2)
1.72(4)
1.82(2)
1.81(2)
1.28(2)
P(3)-C(10)
N(1)-C(9)
P(4)-C(10)
Bond Angles (deg)
Ru(1)-Ru(2)-Ru(3) 60.92(5) Ru(1)-Ru(3)-Ru(2) 58.59(5)
Ru(2)-Ru(1)-Ru(3) 60.49(5) Ru(1)-Ru(3)-P(3)
169.0(1)
151.5(1)
169.3(7)
143.6(5)
149.1(7)
138.0(11)
113.6(13)
Ru(3)-Ru(1)-P(1)
Ru(2)-Ru(1)-C(1)
N(1)-Ru(2)-C(3)
C(5)-Ru(3)-C(6)
Ru(1)-N(1)-Ru(2)
Ru(2)-N(1)-C(9)
154.7(1) Ru(3)-Ru(2)-P(2)
146.3(6) N(1)-Ru(1)-C(2)
166.6(6) Ru(1)-Ru(2)-C(4)
163.6(8) Ru(2)-Ru(3)-C(7)
83.7(5) Ru(1)-N(1)-C(9)
138.0(11) C(60)-C(9)-C(70)
almost coplanar. The structural features of the 2,2-
diphenyl-1-azavinylidene ligand of complex 3 are com-
parable to those found in other binuclear3,4,33-36 or
trinuclear13-20 complexes containing edge-bridging 2-H-
1-azavinylidene ligands.
The known iron complex [Fe3(µ-H)(µ3-NdCHMe)-
(CO)9] (J in Chart 1) contains a face-bridging 1-azavi-
nylidene ligand.21 Such a coordination mode for 1-aza-
vinylidene ligands had no precedents in ruthenium
chemistry. This led us to investigate the thermolysis
reactions of compounds 1-3.
No reaction was observed when complex 1 was stirred
in THF or 1,2-dichloroethane at reflux temperature for
24 h. However, IR monitoring of a refluxing solution
of compound 2 in THF showed that, after 1 h, the
starting material was completely transformed into a
new compound which was formulated as the face-
bridged derivative [Ru3(µ-H)(µ3-NdCPh2)(µ-dppm)(CO)7]
(4) on the basis of its analytical and spectroscopic data
(Scheme 2). Only terminal CO ligands were observed
(26) (a) Angelici, R. J .; Basolo, F. J . Am. Chem. Soc. 1962, 84, 2495.
(b) Atwood, J . D.; Brown, T. L. J . Am. Chem. Soc. 1976, 98, 3160.
(27) Andreu, P. L.; Cabeza, J . A.; Cuya´s, J . L.; Riera, V. J .
Organomet. Chem. 1992, 427, 363.
(28) Andreu, P. L.; Cabeza; J . A.; Riera, V.; Bois, C.; J eannin, Y. J .
Chem. Soc., Dalton Trans. 1990, 3347.
(29) Andreu, P. L.; Cabeza; J . A.; Pellinghelli, M. A.; Riera, V.;
Tiripicchio, A. Inorg. Chem. 1991, 30, 4611.
(30) Cabeza, J . A.; del R´ıo, I.; Llamazares, A.; Riera, V.; Garc´ıa-
Granda, S.; Van der Maelen, J . F. Inorg. Chem. 1995, 34, 1620.
(31) Shen, J .-K.; Basolo, F.; Nombel, P.; Lugan, N.; Lavigne, G.
Inorg. Chem. 1996, 35, 755.
(33) Mele´ndez, E.; Arif, A. M.; Ziegler, M. L.; Ernst, R. D. Angew.
Chem., Int. Ed. Engl. 1988, 27, 1099.
(34) Carofiglio, T.; Stella, S.; Floriani, C.; Chiesi-Vila, A.; Guastinti,
C. J . Chem. Soc., Dalton Trans. 1989, 1957.
(35) Klose, A.; Solari, E.; Ferguson, R.; Floriani, C.; Chiesi-Vila, A.;
Rizzoli, C. Organometallics 1993, 12, 2414 and references therein.
(36) Churchill, M. R.; Lin, K. K. G. Inorg. Chem. 1975, 14, 1675.
(32) Rosenberg, E.; Bracker-Novak, J .; Gellert, R. W.; Aime, S.;
Gobetto, R.; Osella, D. J . Organomet. Chem. 1989, 365, 163.
+
+

3008 Organometallics, Vol. 15, No. 13, 1996
Andreu et al.
1
in its IR spectrum (Table 1). The H, 31P, and 13C NMR
Sch em e 3
spectra indicated that the structure of the compound is
closely related to that of its precursor 2, having the three
bridging ligands spanning the same Ru-Ru edge. Thus,
the proton spectrum shows the resonances of all the
organic ligands and a triplet for the hydride ligand with
a J (H-P) coupling constant very similar to those found
for compounds 2 and 3 (Table 2), while the 31P{1H}
NMR spectrum consists of only one singlet. Its 13C{1H}
NMR spectrum (Table 3) was more informative since,
although only three CO resonances of intensities 3:2:2
were observed (four CO resonances of intensities 1:2:
2:2 are expected for the structure depicted in Scheme
2), the resonance of the azavinylidene carbon atom was
observed at 144.6 ppm, shifted 31-37 ppm to lower
frequencies from the NdC resonances of all the edge-
bridged compounds described in this article. These data
strongly support that the 1-azavinylidene ligand in
complex 4 is behaving as a face bridging ligand, with
the CdN double bond coordinated to the unique ruthe-
nium atom, as shown in Scheme 2. This structural
assignment is also supported by the fact that complex
4 reacted readily with carbon monoxide (1 atm, THF,
18 °C, 1 h) to give its octacarbonyl precursor 2. We were
unable to grow single crystals of compound 4, and
therefore, we could not confirm its structure by diffrac-
tion methods. As far as we know, this type of coordina-
tion for 1-azavinylidene ligands has only been reported
for the iron cluster [Fe3(µ-H)(µ3-NdCHMe)(CO)9].21
Ruthenium cluster complexes containing µ3-vinylidene
ligands are also scarce,37 although more examples are
known for triiron carbonyl clusters.38
Thermolysis of compound 3 was expected to result in
a release of CO accompanied by coordination of either
the free phophorus atom or the CdN moiety of the
azavinylidene ligand. However, no transformation was
observed when compound 3 was stirred in THF at reflux
temperature for 2.5 h. This result indicates that the
CO ligands of heptacarbonyl derivatives of the triru-
thenium 1-azavinylidene system have no tendency to
be replaced by other ligands.
Com plexes Der ived fr om Com pou n d 1 an d Tr iph -
en ylp h osp h in e. Triphenylphosphine is a monodentate
ligand and is less basic than dppm. In addition, the
stereochemistry of bis(triphenylphosphine) trinuclear
clusters29 is in most cases different from that of µ-η2-
dppm trinuclear derivatives,27 in which the rigidity of
the bidentate ligand forces the phosphorus atoms to be
coordinated to adjacent metal atoms in neighboring
positions (Scheme 2). Therefore, we decided to prepare
triphenylphosphine derivatives of compound 1, expect-
ing that they would exhibit new reactivity and struc-
tural attributes.
cluster 5 (Scheme 3) was inferred from its 1H NMR
spectrum (Table 2), which shows the hydride as a
doublet with a J (H-P) coupling constant of 7.4 Hz. This
value is within the range expected for cis arrangements
of phosphine and hydride ligands in trinuclear clus-
ters.27-29
The thermolysis of complex 5 in refluxing THF led to
a mixture whose composition varied with the reaction
time. Monitoring of the reaction by IR and NMR
spectroscopies indicated that the face-bridged derivative
[Ru3(µ-H)(µ3-NdCPh2)(PPh3)(CO)8] (6) was the first
product formed, but before all 5 was consumed, it
started to decompose progressively into a mixture of the
bis(phosphine) orthometalated derivative [Ru3(µ-H)2(µ-
NdCPhC6H4)(PPh3)2(CO)7] (8), an as yet unidentified
compound which contains no hydride and no phosphine
ligands (hereafter named X), and some other products
in very small amounts. Thus, for example, a roughly
1:5:1:1 mixture of 5, 6, 8, and X was obtained after 12
h of reaction (NMR integration). Unfortunately, all
attempts to separate the mixtures by chromatographic
means induced the decomposition of complexes 6 and
X on the chromatographic supports (silica or alumina)
and only 5 and 8 could be eluted and separated.
Although we could not get complex 6 in a pure form,
we managed to get most of its IR (Table 1) and NMR
(Tables 2 and 3) data from the spectra of mixtures
obtained at different reaction times. The structure
proposed for this compound in Scheme 3 is based on
these data. As occurs in complex 4, the 13C NMR
resonance of the NdC carbon atom is observed at low
frequency, 145.6 ppm, indicating that the 1-azavi-
nylidene ligand occupies a face-bridging position in the
cluster. Eight CO resonances are also observed in the
13C NMR spectrum (Table 3). The 1H and 31P{1H} NMR
spectra also confirm the presence of a hydride and a
phosphine ligands in a cis arrangement (J (H-P) ) 10.4
Hz).28,29
The room-temperature reaction of compound 1 with
1 equiv of triphenylphosphine (THF, 72 h) led to the
monosubstituted derivative [Ru3(µ-H)(µ-NdCPh2)(PPh3)-
(CO)9] (5). The use of an excess of phosphine ligand
reduced the reaction time without formation of disub-
stituted products as long as the temperature was not
increased. The position of the phosphine ligand in
(37) (a) Dodsworth, R.; Dutton, T.; J ohnson, B. F. G.; Lewis, J .;
Raithby, P. R.; Acta Crystallogr., Sect. C 1989, 45, 707. (b) Ziller, J .
W.; Bower, D. K.; Dalton, D. M.; Keister, K. B.; Churchill, M. R.
Organometallics 1989, 8, 492.
(38) (a) Vites, J . C.; J acobsen, G.; Dutta, T. K.; Fehlner, T. P. J .
Am. Chem. Soc. 1985, 107, 5563. (b) Dutta, T. K.; Vites, J . C.; Fehlner,
T. P. Organometallics 1986, 5, 385. (c) Dutta, T. K.; Meng, X.; Vites,
J . C.; Fehlner, T. P. Organometallics 1987, 6, 2191.
The reaction of complex 1 with 2 equiv of triphen-
+
+

Triruthenium Carbonyl Cluster Complexes
Organometallics, Vol. 15, No. 13, 1996 3009
ylphosphine in dichloromethane at reflux temperature
for 12 h (only 5 is formed at room temperature) led to a
mixture of two compounds, subsequently identified as
[Ru3(µ-H)(µ-NdCPh2)(PPh3)2(CO)8] (7) and [Ru3(µ-H)2-
(µ-NdCPhC6H4)(PPh3)2(CO)7] (8). Shorter reaction times
resulted in mixtures of compounds 5, 7, and 8; the
shorter the time the more 5 and the less 8 were observed
by IR and NMR spectroscopies, whereas longer reactions
times or higher temperatures resulted in more 8, less
7, and none of 5. Complex 8 was quantitatively pre-
pared by treating 1 with 2 equiv of triphenylphosphine
in THF at reflux temperature for 4 h. All attempts to
separate complex 7 from its mixtures with 5 and 8 by
chromatographic methods failed, since 7 was trans-
formed into compound 8 on the chromatographic sup-
ports (silica or alumina). However, we did obtain pure
complex 7 by treating 8 with carbon monoxide (1 atm,
CH2Cl2, 18 °C, 30 min).
However, compound 1 is stable at high temperatures
(50-100 °C), whereas the substituted compounds 2, 5,
and 7 release CO on heating, promoting the coordination
of the CdN moiety of the azavinylidene ligand (case of
2 and 5) or the C-H activation of one of the phenyl rings
(case of 7). We have found no answers that could
explain this behavior. It is also intriguing why, in the
case of complex 7, C-H activation is preferred over CdN
coordination.
Exp er im en ta l Section
Gen er a l Da ta . Solvents were dried over sodium diphenyl
ketyl (THF, diethyl ether, hydrocarbons) or CaH2 (dichlo-
romethane, 1,2-dichloroethane) and distilled under nitrogen
prior to use. Unless otherwise stated, the reactions were
carried out under nitrogen at room temperature, using
Schlenk-vacuum line techniques, and were routinely moni-
tored by solution IR spectroscopy (carbonyl stretching region)
and by spot thin-layer chromatography (TLC). All reagents
and TLC plates were used as received from Aldrich. Infrared
spectra (Table 1) were recorded on a Perkin-Elmer FT 1720-X
spectrophotometer, using 0.1-mm CaF2 cells. 1H (Table 2), 31P-
{1H} (Table 2), and 13C{1H} (Table 3) NMR spectra were run
at 18 °C with Bruker AC-200 and AC-300 instruments, using
SiMe4 (internal, for 1H and 13C) or 85% H3PO4 (external, for
31P) as standards (δ ) 0 ppm). Fast atom bombardment mass
spectra were obtained on a Finningan Mat-95 spectrometer,
using nitrobenzyl alcohol as matrix and cesium as bombarding
gas. Microanalyses were obtained from the University of
Oviedo Analytical Service.
[Ru 3(µ-H)(µ-NdCP h 2)(CO)10] (1). A 1.6 M solution of
BuLi in hexane (3.23 mL, 5.168 mmol) was injected into a
solution of benzophenone imine (0.867 mL, 5.156 mmol) in
THF (50 mL). After the solution was stirred for 45 min, [Ru3-
(CO)12] (3.0 g, 4.695 mmol) was added. The resulting solution
was stirred until all ruthenium carbonyl had reacted (disap-
pearance of the strong 2060 cm-1 band and appearance of new
ν(µ-CO) bands at 1781 and 1774 cm-1 in the IR spectrum of
the solution, ca. 2 h), being then treated with trifluoroacetic
acid (1 mL). The solvent was removed under reduced pressure,
and the residue was separated by column chromatography
(neutral alumina, activity I, 25 × 2 cm). Hexane eluted some
[Ru3(CO)12]. Hexane-dichloromethane (1:1) eluted complex
1, which was obtained as an orange solid (2.300 g, 67%). Anal.
Calcd for C23H11NO10Ru3: C, 36.13; H, 1.45; N, 1.83. Found:
C, 36.49; H, 1.68; N, 1.71. MS (m/ e): 764 (M+).
The structures proposed for compounds 7 and 8 in
Scheme 3 are based on analytical and spectroscopic
data. Both gave satisfactory CHN analyses and the
corresponding molecular ions in their respective mass
spectra. Their 31P{1H} NMR spectra consist of two
doublets with large coupling constants (Table 2), indi-
cating that the two phosphine ligands occupy equatorial
positions on different metal atoms, being collinear with
a metal-metal bond.29 The 1H NMR spectrum of
compound 7 shows the hydride as a doublet of doublets
(Table 2), with the largest J (H-P) coupling constant,
5.5 Hz, suggesting a cis-hydride-phosphine arrange-
ment,28,29 while the small value of the other coupling
constant indicates that the hydride is far away from the
other phosphine ligand. These data are conclusive as
far as the position of the ligands in cluster 7 is concerned
(Scheme 3). The 1H NMR spectrum of compound 8
shows two hydride resonances, both as doublets of
doublets, with J (H-P) coupling constants (Table 2)
which indicate that both hydrides are cis to one phos-
phine and far away from the other phosphine. The
presence of two hydride ligands in the cluster is
consistent with the observation of an orthometalated
phenyl ring in the DEPT 13C NMR spectra of the
complex, which show the resonances of that ring spread
over the range 170-120 ppm (Table 3). The fact that
all these resonances are singlets confirms that (a) the
orthometalated ring does not belong to the phosphine
ligands but to the azavinylidene ligand (this is also
suggested by the 31P{1H} NMR spectrum, which is very
similar to that of complex 7) and (b) the metalation has
taken place onto the ruthenium atom which is not
attached to any of the phosphine ligands. Moreover, the
hydride ligand which comes from the metalated ring is
expected to occupy a bridging position cis to the meta-
lated carbon atom, as shown in Scheme 3.
[Ru 3(µ-H)(µ-NdCP h 2)(µ-d p p m )(CO)8] (2). A solution of
compound 1 (50 mg, 0.065 mmol) and dppm (25.1 mg, 0.065
mmol) in THF (20 mL) was stirred for 24 h. The solvent was
removed under reduced pressure and the residue chromato-
graphed on a column of neutral alumina (activity I, 10 × 2
cm). Hexane-toluene (1:1) eluted complex 2, which was
obtained as a red solid (60 mg, 85%). Anal. Calcd for C46H33
-
NO8P2Ru3: C, 50.55; H, 3.04; N, 1.28. Found: C, 50.63; H,
2.97; N, 1.13. MS (m/ e): 1095 (M+ + 2).
[Ru 3(µ-H)(µ-NdCP h 2)(µ-d p p m )(d p p m )(CO)7] (3). A so-
lution of compound 1 (200 mg, 0.260 mmol) and dppm (200
mg, 0.520 mmol) in THF (20 mL) was stirred for 12 h. The
color changed from orange to dark red. The solvent was
removed under reduced pressure and the residue chromato-
graphed on a column of neutral alumina (activity I, 10 × 2
cm). Dichloromethane eluted complex 3, which was obtained
as a red solid (350 mg, 92%). Anal. Calcd for C70H55NO7P4-
Ru3: C, 58.01; H, 3.83; N, 0.97. Found: C, 57.69; H, 3.97; N,
0.89. MS (m/ e): 1451 (M+ + 2).
[Ru 3(µ-H)(µ3-NdCP h 2)(µ-d p p m )(CO)7] (4). A solution of
compound 1 (50 mg, 0.065 mmol) and dppm (25.1 mg, 0.065
mmol) in THF (20 mL) was stirred at reflux temperature for
1 h. The solvent was removed under reduced pressure and
the residue washed with hexane (3 × 5 mL) to give complex 2
as an orange solid (64 mg, 93%). Anal. Calcd for C45H33NO7P2-
As far as we know, compound 8 is the first complex
to contain an orthometalated 1-azavinylidene ligand
bridging two metal atoms. Although the orthometala-
tion of benzophenone imine has been previously re-
ported for mononuclear complexes of ruthenium5 and
osmium,6-11 to give metallacycles of type D (Chart 1),
the ligand in these compounds cannot be considered as
an azavinylidene.
Although [Ru3(CO)12] is an exception, it is generally
accepted that the more CO ligands that a triruthenium
carbonyl cluster complex possesses, the easier is the
substitution of a single CO ligand by other ligands.
+
+

3010 Organometallics, Vol. 15, No. 13, 1996
Andreu et al.
Ta ble 5. Cr ysta llogr a p h ic a n d Refin em en t Da ta
Ru3: C, 50.75; H, 3.12; N, 1.32. Found: C, 50.61; H, 3.40; N,
1.21. MS (m/ e): 1037 (M+ - CO).
for 3‚0.5CH2Cl2
.
Rea ction of Com p ou n d 4 w ith Ca r bon Mon oxid e.
Carbon monoxide was bubbled through a solution of compound
4 (20 mg, 0.019 mmol) in THF (10 mL) for 1 h. The color
changed from orange to red. An IR spectrum of the resulting
solution indicated the complete transformation of compound
4 into compound 2.
formula
fw
C70H55NO7P4Ru3 0.5CH2Cl2
1491.78
cryst syst
space group
a,b,c, Å
R,â,γ, deg
V, Å3
triclinic
P1h
12.284(4), 13.551(4), 20.895(8)
75.14(3), 86.58(3), 82.44(3)
3331(6)
Z
D
2
1.49
8.44
0.78, 1.18
[Ru 3(µ-H)(µ-NdCP h 2)(P P h 3)(CO)9] (5). Triphenylphos-
phine (17.1 mg, 0.065 mmol) was added to a solution of
compound 1 (50 mg, 0.065 mmol) in THF (20 mL). After the
solution was stirred for 72 h, the solvent was removed under
reduced pressure and the residue chromatographed on a
column of neutral alumina (activity I, 10 × 2 cm). Hexane-
toluene (1:1) eluted complex 5, which was obtained as an
orange solid (33 mg, 51%). Anal. Calcd for C40H26NO9PRu3:
C, 48.10; H, 2.62; N, 1.40. Found: C, 48.39; H, 2.80; N, 1.44.
MS (m/ e): 999 (M+).
calcd, g/cm3
µ, cm-1
min, max corr factors
cryst size, mm
radiation (λ, Å)
diffractometer
monochromator
temp, K
0.55 × 0.40 × 0.35
Mo KR (0.7107)
Enraf-Nonius CAD4
graphite
293(2)
ω-2θ
0.8 + 0.345 tan θ
-11 to 11, -12 to 13, 0 to 20
1-20
6422
6192
0.058
3796
480
0.058
0.069
0.1
scan method
scan range, deg
h,k,l range
[Ru 3(µ-H)(µ3-NdCP h 2)(P P h 3)(CO)8] (6). A solution of
complex 5 (100 mg, 0.100 mmol) in THF (20 mL) was stirred
at reflux temperature for 12 h. The solvent was removed
under reduced pressure, and the residue was analyzed by IR
and 1H, 31P{1H}, and 13C{1H} NMR spectroscopies, which
indicated a 1:5:1:1 mixture of compounds 5, 6, 8, and X,
respectively (see the Results and Discussion section). All
attempts to separate compound 6 from the mixtures by
chromatographic methods were unsuccessful, since it decom-
posed on the supports (silica or alumina) and could not be
eluted.
θ range, deg
no. of rflns collctd
no. of indep rflns
Rint ) Σ(I - I )/ΣI
no. of rflns with Fo2 > 3σ(Fo
no. of params
Ra
2
)
b
Rw
∆/σ
max, min ∆F, e/Å3
1.06, -0.80
R ) Σ|Fo - |Fc||/ΣFo. bRw ) [Σw(Fo - |Fc|)2/Σw(Fo)2]1/2, unit
a
weights.
Rea ction of Com p ou n d 1 w ith 2 equ iv of P P h 3. Tri-
phenylphosphine (34.3 mg, 0.131 mmol) was added to a
solution of compound 1 (50 mg, 0.065 mmol) in dichlo-
romethane (20 mL). After the solution was stirred at reflux
temperature for 12 h, the solvent was removed under reduced
pressure. The 1H and 31P{1H} NMR spectra of the residue
indicated a 5:1 mixture of compounds 7 and 8 accompanied
by very small amounts of two other unidentified products. All
attempts to isolate complex 7 free of impurities by this method
were unsuccessful, since it was readily converted into com-
pound 8 on the supports used for chromatographic separations
(silica, alumina).
An absorption correction was applied using the program
DIFABS39 from CRYSTALS.40 No extinction correction was
necessary.
The structure was solved by direct methods and subsequent
Fourier maps. Non-hydrogen atoms, except the carbon atoms
of the phenyl groups and the atoms of the CH2Cl2 solvent
molecule, were refined anisotropically. Only a few hydrogen
atoms were found on difference maps, so they all were placed
riding on their parent atoms with an overall isotropic thermal
parameter, except the bridging hydrogen atom H(1), which was
found and its positional and thermal parameters were refined
isotropically. Refinements were carried out in three blocks
by minimizing the function Σw(Fo - |Fc|)2. All calculations
were performed with CRYSTALS.40 Scattering factors were
taken from the appropriate reference41 and were corrected for
anomalous dispersion. The structure plot in Figure 1 was
carried out with the CAMERON package.42 Selected inter-
atomic distances and angles are given in Table 4.
[Ru 3(µ-H)(µ-NdCP h 2)(P P h 3)2(CO)8] (7). Carbon monox-
ide was bubbled through a dichloromethane (10 mL) solution
of compound 8 (50 mg, 0.042 mmol) for 30 min. The color
changed from orange to red. The solvent was removed under
reduced pressure, and the solid residue was washed with
pentane to give compound 7 as a red solid (45 mg, 88%). Anal.
Calcd for C57H41NO8P2Ru3: C, 55.52; H, 3.35; N, 1.14.
Found: C, 55.48; H, 3.51; N, 1.04. MS (m/ e): 1233 (M+).
[Ru 3(µ-H)2(µ-NdCP h C6H4)(P P h 3)2(CO)7] (8). A solution
of compound 1 (50 mg, 0.065 mmol) and triphenylphosphine
(43.3 mg, 0.131 mmol) in THF (10 mL) was stirred at reflux
temperature for 4 h. The color changed from red to orange.
The solvent was removed under reduced pressure, and the oily
residue was separated by column chromatography (neutral
alumina, activiy I, 15 × 2 cm). Elution with hexane-toluene
(1:1) afforded compound 8, which was obtained as a yellow-
orange solid (75 mg, 96%). Anal. Calcd for C56H41NO7P2Ru3:
C, 55.81; H, 3.43; N, 1.16. Found: C, 55.90; H, 3.50; N, 1.09.
MS (m/ e): 1205 (M+).
Ack n ow led gm en t. This research was supported by
the DGICYT (Spain, Grant PB92-1007) and the CNRS
(France). We are grateful to a reviewer for invaluable
comments.
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates and U values, bond distances and angles, aniso-
tropic thermal parameters, and H coordinates and U values
for 3‚0.5CH2Cl2 (7 pages). Ordering information is given on
any current masthead page.
Cr ysta l Str u ctu r e of Com p lex 3‚0.5CH2Cl2. A red,
parallelepipedal crystal of the solvate 3‚0.5CH2Cl2, grown by
layering pentane on a solution of 3 in dichloromethane, at -20
oC, was used for the X-ray analysis. Selected crystallographic
and refinement data are collected in Table 5. Unit cell
dimensions were determined from the angular settings of 25
well-centered reflections. The space group was proposed after
structure determination. Two standard reflections were moni-
tored periodically, showing no change during data collection.
Corrections for Lorentz and polarization effects were made.
OM9601662
(39) Walker, N.; Stuart, D. Acta Crystallogr., Sect. A 1983, 39, 158.
(40) Carruthers, J . R.; Watkin, D. J . CRYSTALS, an Advanced
Crystallographic Computer Program; University of Oxford Chemical
Laboratory: Oxford, U.K., 1985.
(41) International Tables for X-Ray Crystallography; Kynoch
Press: Birmingham, U.K., 1974; Vol. 4 (present distributor: Kluwer
Acad. Publ., Dordrecht, The Netherlands).
(42) Pearce, L. J .; Watkin, D. J . CAMERON; University of Oxford
Chemical Laboratory: Oxford, U.K., 1985.
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