Deprotonation of Cp2Ti(SH)2 with mononuclear rhodium and iridium compounds: A new route to trinuclear early-late heterobimetallic complexes

Article abstract of DOI:10.1021/om990623p

The reaction of Cp₂Ti(SH)₂ with [M(acac)(diolefin)] (acac = acetylacetonate) yields the complexes [Cp(acac)Ti(μ₃-S)₂{M(diolefin)}₂] (M = Rh, diolefin = 1,5-cyclooctadiene (cod) (1); diolefin = tetrafluorobenzobarrelene (tfbb) (2); M = Ir, diolefin = cod (3)). The formation of the trinuclear heterobimetallic complexes results from a complex reaction involving the deprotonation of the hydrosulfido ligands along with the addition of the late-metal fragment(s), followed by the release of cyclopentadiene and the coordination of acetylacetonate to the titanium center. Similarly, the reaction of Cp₂Ti(SH)₂ with [M(quinol)(diolefin)] (quinol = 8-oxyquinolinate) gives the complexes [Cp(quinol)Ti(μ₃-S)₂{M(diolefin)}₂] (M = Rh, diolefin = cod (4); tfbb (5); M = Ir, diolefin = cod (6)), which incorporate the 8-oxyquinolinate ligand. The d⁰-d⁸ trinuclear early-late heterobimetallic complexes exhibit triangular TiRh₂ and TiIr₂ cores doubly capped by two μ₃-sulfido ligands. Deprotonation of Cp₂Ti(SH)₂ with the mononuclear carbonyl complexes [M(acac)(CO)₂] (M = Rh, Ir) yields the ion-pair complexes [Cp₂Ti(acac)][M₃(μ₃-S)₂(CO) ₆] (M = Rh (7); M = Ir (8)), which result from complete transference of the sulfido ligands to the d⁸ metal centers. Carbonylation of the diolefin complexes [Cp(acac)Ti(μ₃-S)₂{M(diolefin)}₂] or [Cp(quinol)Ti(μ₃-S)₂{M(diolefin)}₂] yields the compounds [Cp(acac)Ti(μ₃-S)₂{M(CO)₂}₂] (M = Rh (9); M = Ir (10)) and [Cp(quinol)Ti(μ₃-S)₂{M(CO)₂}₂] (M = Rh (11); M-Ir (12)), respectively. Replacement reactions on the carbonyl complexes with triphenylphosphine give the disubstituted complexes [Cp(acac)Ti(μ₃-S)₂-{M(CO)(PPh₃)} ₂] (M = Rh (13); M = Ir (14)) or [Cp(quinol)Ti(μ₃-S)₂{M(CO)(PPh₃)} ₂] (M = Rh (15); M = Ir (16)), which are obtained as mixtures of cis and trans isomers. The molecular structures of complexes 1 and 8 have been determined by X-ray diffraction methods.

Full text of DOI:10.1021/om990623p

Organometallics 1999, 18, 5299-5310
5299
Dep r oton a tion of Cp Ti(SH) w ith Mon on u clea r Rh od iu m
2
2
a n d Ir id iu m Com p ou n d s: A New Rou te to Tr in u clea r
Ea r ly-La te Heter obim eta llic Com p lexes
Miguel A. Casado, J es u´ s J . P e´ rez-Torrente, Miguel A. Ciriano,*
Andrew J . Edwards, Fernando J . Lahoz, and Luis A. Oro*
Departamento de Qu ı´ mica Inorg a´ nica, Instituto de Ciencia de Materiales de Arag o´ n,
Universidad de Zaragoza-CSIC, 50009-Zaragoza, Spain
Received August 4, 1999
The reaction of Cp
complexes [Cp(acac)Ti(µ
2
Ti(SH)
2
with [M(acac)(diolefin)] (acac ) acetylacetonate) yields the
] (M ) Rh, diolefin ) 1,5-cyclooctadiene (cod) (1);
3
-S) {M(diolefin)}
2
2
diolefin ) tetrafluorobenzobarrelene (tfbb) (2); M ) Ir, diolefin ) cod (3)). The formation of
the trinuclear heterobimetallic complexes results from a complex reaction involving the
deprotonation of the hydrosulfido ligands along with the addition of the late-metal fragment-
(
s), followed by the release of cyclopentadiene and the coordination of acetylacetonate to the
titanium center. Similarly, the reaction of Cp Ti(SH) with [M(quinol)(diolefin)] (quinol )
-oxyquinolinate) gives the complexes [Cp(quinol)Ti(µ -S) {M(diolefin)} ] (M ) Rh, diolefin
cod (4); tfbb (5); M ) Ir, diolefin ) cod (6)), which incorporate the 8-oxyquinolinate ligand.
2
2
8
)
3
2
2
0
8
The d -d trinuclear early-late heterobimetallic complexes exhibit triangular TiRh
2
and
with the
] (M ) Rh, Ir) yields the ion-pair complexes
] (M ) Rh (7); M ) Ir (8)), which result from complete
TiIr
mononuclear carbonyl complexes [M(acac)(CO)
Cp Ti(acac)][M (µ -S) (CO)
transference of the sulfido ligands to the d metal centers. Carbonylation of the diolefin
complexes [Cp(acac)Ti(µ -S) {M(diolefin)} ] or [Cp(quinol)Ti(µ -S) {M(diolefin)} ] yields the
compounds [Cp(acac)Ti(µ -S) {M(CO) ] (M ) Rh (9); M ) Ir (10)) and [Cp(quinol)Ti(µ
S) {M(CO) ] (M ) Rh (11); M ) Ir (12)), respectively. Replacement reactions on the carbonyl
complexes with triphenylphosphine give the disubstituted complexes [Cp(acac)Ti(µ -S)
M(CO)(PPh )} ] (M ) Rh (13); M ) Ir (14)) or [Cp(quinol)Ti(µ -S) {M(CO)(PPh )} ] (M )
2
cores doubly capped by two µ
3 2 2
-sulfido ligands. Deprotonation of Cp Ti(SH)
2
[
2
3
3
2
6
8
3
2
2
3
2
2
3
2
2
}
2
3
-
2
2 2
}
3
2
-
{
3
2
3
2
3
2
Rh (15); M ) Ir (16)), which are obtained as mixtures of cis and trans isomers. The molecular
structures of complexes 1 and 8 have been determined by X-ray diffraction methods.
In tr od u ction
of the synergism between the metals in both catalytic3
and stoichiometric reactions.
An elegant synthetic approach for early-late hetero-
bimetallic complexes (ELHB) established by Stephan
4
The chemistry of heteropolynuclear complexes con-
taining widely divergent transition metals is of current
interest and of relevance to the chemistry involved in
and co-workers involves early-metal complexes as met-
1
certain types of industrial catalytic processes. Among
allaligands for late-transition metal species.5 They
them, complexes with bridging sulfido ligands have a
broad scope ranging from biological systems and applied
catalysis, such as dehydrosulfurization, to novel chem-
include titanium and zirconium complexes with termi-
6
7
nal thiolate, phosphide, and alkoxyalkylphosphine
8
9
ligands, pendant chelating metallaligands, and also
2
istry of molecular systems. Moreover, early-late het-
erometallic complexes, which incorporate electron-poor
and electron-rich metals, open possibilities to new
reactivity patterns, such as the cooperative heterome-
tallic activation of small molecules, and the exploration
(3) (a) Herrmann, W. A.; Cornils B. Angew. Chem. 1997, 109, 1074;
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Chem. 1996, 515, 19. (c) Hostetler, M. J .; Butts, M. D.; Bergman, R.
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C.; Broussier, R.; Gautheron, B.; Delmas, G.; Trouve, G.; Kubicki, M.
Organometallics 1993, 12, 1021. (e) Gelmini, L.; Stephan, D. W.
Organometallics 1988, 7, 849. (f) Choukroun, R.; Gervais, D.; J aud,
J .; Kalck, P.; Senocq, F. Organometallics 1986, 5, 67. (g) Senocq, F.;
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(2) (a) Transition Metal Sulfur Chemistry: Biological and Industrial
Significance; Stiefel, E. I., Matsumoto, K., Eds.; American Chemical
Society: Washington, DC, 1996. (b) Firth, A. V.; Witt, E.; Stephan, D.
W. Organometallics 1998, 17, 3716. (c) Nishioka, T.; Isobe, K.;
Kinoshita. I.; Ozawa, Y.; Vazquez de Miguel, A.; Nakai, T.; Miyajama,
S. Organometallics 1998, 17, 1637. (d) Shiu, K. B.; Wang, S. L.; Liao,
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1
0.1021/om990623p CCC: $18.00 © 1999 American Chemical Society
Publication on Web 11/17/1999

5
300 Organometallics, Vol. 18, No. 25, 1999
Casado et al.
macrocyclic metallaligands.10 Other useful metallali-
gands are based on functionalized cyclopentadienyl
groups in early-metallocene complexes,11 and remark-
able synthetic strategies involve the use of bis(cyclo-
pentadienyl)titanacyclobutanes or methylcarbene ti-
tanium complexes13 to give methylene-bridged early-
late heterometallic complexes.
(µ-OMe)(diolefin)}2] gives the tetranuclear heterobime-
tallic complexes [CpTi(µ3-S3){Rh(diolefin)}3], in which
the group [CpTi(S)3] caps a trimetallic triangle of the
3-
1
6
3-
late-metals. Moreover, the group [CpTi(S)3] , which
has no simple precursors in the chemistry of titanium,
is a metallaligand generated in these reactions from the
cubane clusters [Cp2Ti2(µ3-S)4{M(diolefin)}2] as inter-
mediates and stabilized by coordination to the late-
1
2
A few early-late complexes containing group 4 metals
3
d,14
metal fragments. Indeed, a general way to [CpTi(µ3-
with sulfido bridging ligands have been reported
S3){M(diolefin)}3] involves the reactions of the anion
probably because the possible precursors, the early-
metal complexes with terminal sulfido groups, are
2
-
[
Cp2Ti2(µ-S)2(S)2] with the chloro complexes [{M(µ-Cl)-
1
7
1
5
(diolefin)} ] (M ) Rh, Ir). Furthermore, the reactions
of Cp2Ti(SH)2 with rhodium and iridium complexes are
rare. Very recently we have developed a synthetic
2
methodology based on the acid-base chemistry of Cp2-
0
8
sensitive to the presence of oxygen donor ligands such
as water, providing in favorable cases the access to oxo-
sulfide titanium-rhodium complexes such as [(CpTi)2-
Ti(SH)2 which leads to d -d early-late heterometallic
complexes. Thus, we have reported that the deprotona-
tion of the bis(hydrosulfido)titanium complex with [{Rh-
1
8
(
µ4-O)(µ3-S)4Rh4(CO)4(PR3)2]. Therefore, the course of
these complex deprotonation reactions of Cp2Ti(SH)2
simultaneous with the addition of rhodium and iridium
fragments (additive-deprotonation) was unpredictable
depending on the oxygen donor ligands in the starting
materials to which the proton is transferred.
(
6) (a) Fujita, K.; Ikeda, M.; Kondo, T.; Mitsudo, T. Chem. Lett. 1997,
5
7. (b) Amador, U.; Delgado, E.; Fornies, J .; Hernandez, E.; Lalinde,
E.; Moreno, M. T. Inorg. Chem. 1995, 34, 5279. (c) Rousseau, R.;
Stephan, D. W. Organometallics 1991, 10, 3399. (d) Wark, T. A.;
Stephan, D. W. Inorg. Chem. 1990, 29, 1731. (e) Wark, T. A.; Stephan,
D. W. Organometallics 1989, 8, 2836. (f) Darensbourg, M. Y.; Silva,
R.; Reibenspies, J .; Prout, C. K. Organometallics 1989, 8, 1315. (g)
Wark, T. A.; Stephan, D. W. Inorg. Chem. 1987, 26, 363.
We describe in this paper the reactions of Cp2Ti(SH)2
with mononuclear rhodium and iridium complexes
containing chelating anionic ligands such as acetylac-
etonate (acac) and 8-oxyquinolinate (quinol), which lead
(
7) (a) Dick, D. G.; Stephan, D. W. Organometallics 1990, 9, 1910.
b) Zheng, P. Y.; Nadasdi, T. T.; Stephan, D. W. Organometallics 1989,
, 1393. (c) Gelmini, L.; Stephan, D. W. Organometallics 1988, 7, 849.
d) Gelmini, L.; Stephan, D. W. Inorg. Chem. 1986, 25, 1222. (e)
(
8
(
0
8
Gelmini, L.; Stephan, D. W. Inorg. Chim. Acta 1986, 111, L17. (f)
Gelmini, L.; Matassa, L. C.; Stephan, D. W. Inorg. Chem. 1985, 24,
to a new unexpected type of d -d trinuclear heterobi-
metallic compounds. In addition, some results on the
reactivity of the new complexes are also reported.
2
585.
(8) (a) Slaughter, L. M.; Wolczanski, P. T. Chem. Commun. 1997,
2
109. (b) Baxter, S. M.; Ferguson, G. S.; Wolczanski, P. T. J . Am. Chem.
Soc. 1988, 110, 4231. (c) Ferguson, G. S.; Wolczanski, P. T.; P a` rk a` nyi,
L.; Zonnevylle, M. C. Organometallics 1988, 7, 1967.
Resu lts
(9) (a) White, G. S.; Stephan, D. W. Organometallics 1987, 6, 2169.
(
b) White, G. S.; Stephan, D. W. Organometallics 1988, 7, 903. (c)
Rea ction of [Cp 2Ti(SH)2] w ith [M(a ca c)(d iole-
fin )] a n d [M(qu in ol)(d iolefin )]. The reaction of Cp2-
Ti(SH)2 with [Rh(acac)(cod)] in toluene (in 1:2 molar
ratio) gives the complex [Cp(acac)Ti(µ3-S)2{Rh(cod)}2]
(1), which is isolated as a dark violet microcrystalline
solid in good yield. The formation of the heterotrinuclear
compound is confirmed by the molecular weight and the
mass spectrum, where several peaks arising from the
Choukroun, R.; Iraqi, A.; Gervais, D.; Daran, J .-C.; J eannin, Y.
Organometallics 1987, 6, 1197. (d) White, G. S.; Stephan, D. W. Inorg.
Chem. 1985, 24, 1499. (e) Choukroun, R.; Gervais, D. J . Organomet.
Chem. 1984, 266, C37.
(10) (a) Nadasdi, T. T.; Stephan, D. W. Inorg. Chem. 1994, 33, 1532.
(
b) Nadasdi, T. T.; Stephan, D. W. Organometallics 1992, 11, 116. (c)
Nadasdi, T. T.; Stephan, D. W. Organometallics 1991, 10, 2037. (d)
Stephan, D. W. J . Chem. Soc., Chem. Commun. 1991, 121. (e) Stephan,
D. W. Organometallics 1990, 9, 2718.
(11) (a) Schenk, W. A.; Gutmann, T. J . Organomet. Chem. 1997, 544,
6
9. (b) Bakhmutov, V. I.; Visseaux, M.; Baudry, D.; Dormond, A.;
1
molecular ion are observed. The H NMR spectrum of
Richard, P. Inorg. Chem. 1996, 35, 7316. (c) Baudry, D.; Dormond, A.;
Visseaux, M.; Monnot, C.; Chardot, H.; Lin, Y.; Bakhmutov, V. I. New
J . Chem. 1995, 19, 921. (d) Tikkanen, W.; Fujita, Y.; Petersen, J . L.
Organometallics 1986, 5, 888. (e) Leblanc, J . C.; Moise, C.; Maisonnat,
A.; Poilblanc, R.; Charrier, C.; Mathey, F. J . Organomet. Chem. 1982,
1
displays a 1:1:2 ratio for the Cp, acac, and cod ligands,
respectively, in agreement with the loss of a cyclopen-
tadienyl ligand from the starting titanium complex and
the incorporation of an acac ligand. The coordination of
the latter to titanium is supported by the downfield shift
of the resonance corresponding to the Cp ligand (6.53
ppm) relative to that observed in [CpTi(µ3-S3){Rh(cod)}3]
2
31, C43.
12) (a) Park, J . W.; Henling, L. M.; Schaefer, W. P.; Grubbs, R. H.
(
Organometallics 1991, 10, 171. (b) Ozawa, F.; Park, J . W.; Mackenzie,
P. B.; Schaefer, W. P.; Henling, L. M.; Grubbs, R. H. J . Am. Chem.
Soc. 1989, 111, 1319. (c) Mackenzie, P. B.; Coots, R. J .; Grubbs, R. H.
Organometallics 1989, 8, 8. (d) Mackenzie, P. B.; Ott, K. C.; Grubbs,
R. H. Pure Appl. Chem. 1984, 56, 59.
(
1
5.71 ppm). In addition, the two strong absorptions at
580 and 1525 cm , observed in the IR spectrum in
-
1
(
13) (a) Butts, M. D.; Bergman, R. G. Organometallics 1994, 13,
899. (b) Butts, M. D.; Bergman, R. G. Organometallics 1993, 12, 4269.
c) Hostetler, M. J .; Butts, M. D.; Bergman, R. G. Inorg. Chim. Acta
1
(
Nujol, are in agreement with a chelating coordination
19
mode of the acac ligand.
1
1
992, 198, 377. (d) Goldberg, K. I.; Bergman, R. G. J . Am. Chem. Soc.
988, 110, 4853.
1
13
1
The H and C{ H} NMR spectroscopic information
and the molecular weight in solution are in agreement
with the structure found in the solid state (see below).
In particular, the plane of symmetry of the molecule
(14) (a) Amemiya, Y.; Kuwata, S.; Hidai, M. Chem. Commun. 1999,
7
11. (b) Yuki, M.; Okazaki, M.; Inomata, S.; Ogino, H. Angew. Chem.,
Int. Ed. 1998, 37, 2126. (c) Tatsumi, K.; Kawaguchi, H.; Inoue, Y.;
Nakamura, A.; Cramer, R. E.; Golen, J . A. Angew. Chem., Int. Ed. Engl.
1
993, 32, 763. (c) Howard, K. E.; Rauchfuss, T. B.; Wilson, S. R. Inorg.
Chem. 1988, 27, 3561. (e) Siedle, A. R.; Gleason, W. B. Inorg. Chem.
986, 25, 4054.
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1
(16) Atencio, R.; Casado, M. A.; Ciriano, M. A.; Lahoz, F. J .; P e´ rez-
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514, 103.
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L. A.; P e´ rez-Torrente, J . J . Organometallics 1999, 18, 3025.
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P e´ rez-Torrente, J . J .; Oro, L. A. Organometallics 1998, 17, 3414.
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(
G.; Kubineck, M. G. J . Am. Chem. Soc. 1997, 119, 4543. (b) Trnka, T.
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Organometallics 1993, 12, 352.

Early-Late Heterobimetallic Complexes
Organometallics, Vol. 18, No. 25, 1999 5301
Sch em e 1
makes equivalent the methyl and CO groups of acac and
1
13
1
two halves of the cod ligands in the H and C{ H}
NMR spectra.
In the same way, the reactions of Cp2Ti(SH)2 with
[
Rh(acac)(tfbb)] and [Ir(acac)(cod)] in toluene give the
compounds [Cp(acac)Ti(µ3-S)2{Rh(tfbb)}2] (2) and [Cp-
acac)Ti(µ3-S)2{Ir(cod)}2] (3), respectively, which are also
F igu r e 1. Aromatic region of the 1H NMR spectrum of
3 2 2 3
[Cp(quinol)Ti(µ -S) {Rh(cod)} ] (4) in CDCl at 293 K
(
showing the numbering scheme for the 8-oxyquinolinate
ligand.
isolated in high yield (Scheme 1). They have a heterot-
rinuclear formulation and structure similar to 1, as
deduced from microanalysis, mass spectra, and NMR
spectroscopy. In particular, the molecular ion is ob-
served in the mass spectrum of 3 (m/z 876). In addition,
the four signals for the olefinic proton and carbon atoms
is observed in all cases (see Experimental Section). The
chemical shift of the Cp resonance in complexes 4-6 is
similar to that observed in the related acetylacetonate
complexes and strongly supports the chelating coordina-
tion of the quinol ligand to the titanium center.
1
13
1
(dCH) in the H and C{ H} NMR spectra of both
Complexes 2, 3, and 4 are dynamic in solution since
line-broadening effects are observed at room tempera-
complexes indicate the presence of a symmetry plane
that relates the two halves of diolefin ligands.
Mononuclear rhodium and iridium diolefin complexes
containing the chelating N,O-donor ligand 8-oxyquino-
linate (quinol) behave similarly to the â-diketonate
1
ture in the olefinic region of the H NMR spectra,
although sharp signals are observed at low temperature.
This dynamic behavior is also observed in complex 1 at
temperatures higher than room temperature. As the
broadening of the signals for the diolefinic ligands are
the single feature observed, no further study was carried
out.
(
[
acac) complexes. Thus, the reactions of Cp2Ti(SH)2 with
Rh(quinol)(cod)] and [Rh(quinol)(tfbb)] (1:2 molar ratio)
in dichloromethane lead exclusively to the formation of
the heterotrinuclear complexes [Cp(quinol)Ti(µ3-S)2{Rh-
Str u ctu r e of [Cp (a ca c)Ti(µ3-S)2{Rh (cod )}2] (1).
The structure of [Cp(acac)Ti(µ3-S)2{Rh(cod)}2] (1) has
been determined by X-ray diffraction methods from a
single crystal obtained by slow diffusion of n-hexane into
a concentrated solution of the complex in toluene at low
temperature. The molecule has crystallographically
imposed Cs symmetry with the three metals occupying
special positions in the symmetry plane (Figure 2).
Compound 1 shows a triangular TiRh2 core capped on
both sides by two nearly symmetrical µ3-sulfido ligands.
The geometry around the rhodium atoms is square-
planar, with the metal atom bonded to both sulfido
(
cod)}2] (4) and [Cp(quinol)Ti(µ3-S)2{Rh(tfbb)}2] (5),
which are isolated in high yield as dark violet solids.
Similarly, the heterotrinuclear iridium complex [Cp-
(
by reaction of Cp2Ti(SH)2 with [Ir(quinol)(cod)] in
dichloromethane (Scheme 1).
quinol)Ti(µ3-S)2{Ir(cod)}2] (6) is obtained in high yield
The heterotrinuclear formulation of complexes 4-6
1
13
1
relies on both the mass and the H and C{ H} NMR
spectra, where a 1:1:2 ratio for the Cp, quinol, and
diolefin ligands, respectively, is observed. The introduc-
tion of the 8-oxyquinolinate ligand in the heterotri-
nuclear structure results in the disappearance of the
mirror plane, and, in consequence, complexes 4-6 have
4
groups and to two olefinic bonds of an η -1,5-cycloocta-
diene ligand. The titanium center adopts a typical four-
legged piano stool arrangement by coordination, apart
1
no symmetry. This is easily deduced from the H and
1
3
1
C{ H} NMR of the complexes since, for example,
5
from the two sulfido ligands, to an η -cyclopentadienyl
complex 5 exhibits one resonance for each proton and
carbon in the molecule. The 8-oxyquinolinate ligand
displays a set of six resonances (Figure 1) showing
standard J H-H couplings,20 which have been unequivo-
cally assigned from the H,H-COSY NMR spectrum for
complex 4 only, since an identical pattern of resonances
and a chelating acetylacetonate ligand.
Selected bond distances and angles for 1 are sum-
marized in Table 1. The Rh-S bond lengths, 2.3419(7)
(20) Casas, J . M.; Falvello, L. R.; Fornies, J .; Martin, A.; Welch, A.
J . Inorg. Chem. 1996, 35, 6009.

5
302 Organometallics, Vol. 18, No. 25, 1999
Casado et al.
F igu r e 3. Molecular diagram of the two ionic metal
complexes of the compound [Cp
8).
2 3 3 2 6
Ti(acac)][Ir (µ -S) (CO) ]
(
Å);18 the greater electron density of the titatium center
in 1, due to the additional presence of the coordinated
acetylacetonate ligand, probably justifies this structural
behavior.
F igu r e 2. Molecular structure of [Cp(acac)Ti(µ
3
-S)
2
{Rh-
(
(
cod)} ] (1) showing the atom-numbering scheme used
2
Interestingly the two Rh‚‚‚Ti separations are mark-
edly different, with values of 3.1992(8) and 2.9904(8)
Å. Most probably this asymmetry is fundamentally due
to the distinct steric requirements of the two ancillary
ligands bonded to the titanium center (Cp and acac),
rather than to electronic effects. In fact, the electronic
characteristics of both rhodium atoms seem to be quite
similar in light of Rh-C, CdC, or Rh-S bond distances,
which are identical for both rhodium atoms (as com-
mented above, only Rh-S bond distances are slightly
different). Although both distances are well over the
symmetry transformation for primed atoms: x, 1/2-y, z).
Ta ble 1. Selected Bon d Dista n ces (Å) a n d An gles
a
(
d eg) for Com p lex 1
Rh(1)‚‚‚Rh(2)
Rh(1)‚‚‚Ti
Rh(1)-S
Rh(1)-C(8)
Rh(1)-C(9)
C(8)-C(9)
Ti-S
2.9207(5)
3.1992(8)
2.3419(7)
2.134(3)
2.143(3)
1.382(5)
2.3750(8)
2.062(2)
2.368(4)
2.371(3)
2.394(3)
Rh(2)‚‚‚Ti
2.9904(8)
2.3333(7)
2.144(3)
2.137(3)
1.373(5)
2.060(3)
1.269(3)
1.507(4)
1.382(4)
Rh(2)-S
Rh(2)-C(12)
Rh(2)-C(13)
C(12)-C(13)
b
Ti-Cp
Ti-O
O-C(2)
Ti-C(4)
C(1)-C(2)
C(2)-C(3)
23
values reported for direct Rh-Ti metal-metal bonds,
Ti-C(5)
the shortest Rh(2)‚‚‚Ti separation in 1 is close to the
values reported in the related tetranuclear complex
Ti-C(6)
S-Rh(1)-S′
83.65(3)
94.1(1)
S-Rh(2)-S′
84.02(3)
94.0(1)
16
[
CpTi(µ3-S3){Rh(tfbb)}3] (2.912-2.940(3) Å) or in di-
c
c
S-Rh(1)-M(1)
S-Rh(2)-M(2)
9
a,10a
12a,b
nuclear thiolate
or methylene-bridged
Rh-Ti
c
c
S′-Rh(1)-M(1)
175.1(1)
115.21(9)
82.60(6)
82.22(2)
85.41(2)
77.32(2)
S′-Rh(2)-M(2)
S-Ti-O′
177.6(1)
136.54(6)
108.12(11)
81.08(7)
78.85(2)
b
complexes (2.827-2.986(1) Å), where a weak dative
S-Ti-Cp
S-Ti-O
S-Ti-S′
b
8
O-Ti-Cp
interaction from the electron-rich d metal to the acidic
O-Ti-O′
0
d titanium center has been suggested. Thus, from the
Rh(1)-S-Ti
Rh(1)-S-Rh(2)
Rh(2)-S-Ti
Rh‚‚‚Ti geometric parameters (also the Rh-S-Ti bond
angles), this weak dative intermetallic interaction could
also be present in 1 between Rh(2) and Ti, but the
longest Rh(1)‚‚‚Ti separation clearly rules out this
possibility for the second rhodium atom. Some kind of
intermetallic interaction between the two d8 metals
could also be suggested from the shorter Rh(1)‚‚‚Rh(2)
a
Primed atoms are related to the unprimed ones by the
b
symmetry transformation x, 1/2-y, z. Cp represents the centroid
of the cyclopentadienyl ligand. M(1) and M(2) represent the
c
midpoints of the olefinic bonds coordinated to Rh(1) and Rh(2),
respectively.
and 2.3333(7) Å, are statistically slightly different, but
compare well with those found in the closely related µ3-
sulfido Rh-Ti heterotetranuclear complex [CpTi(µ3-S3)-
2
4
distance, 2.9207(4) Å.
Rea ction s of [Cp 2Ti(SH)2] w ith [M(a ca c)(CO)2]
M ) Rh , Ir ). The reaction of Cp2Ti(SH)2 with [Rh-
acac)(CO)2] (1:3 molar ratio) in dichloromethane gives
(
(
1
6
{
Rh(tfbb)}3] (2.311-2.338(4) Å), where each sulfido
ligand also bridges two “Rh(diolefin)” moieties to a CpTi
group. However these distances are significantly shorter
than the values observed in related µ2-thiolate bridged
the ion-pair product [Cp2Ti(acac)][Rh3(µ3-S)2(CO)6] (7),
which is isolated as a brown microcrystalline solid in
excellent yield. The related complex [Cp2Ti(acac)][Ir3-
+
Rh-Ti complexes as in [Cp2Ti{S(CH2)3PPh2}2Rh] (2.349
(
µ3-S)2(CO)6] (8) is obtained as dark red microcrystals
by reaction of Cp2Ti(SH)2 with [Ir(acac)(CO)2]
Scheme 2). Complex 8 has been characterized by an
9
a
and 2.380(3) Å) or in [CpTi{S(CH2)3S}2Rh(nbd)] (mean
1
0a
2
.477(2) Å),
as well as in rhodium homonuclear
(
µ2-thiolate derivatives [Rh4(µ-PyS2)2(cod)4] (2.391-
2
1
+
2
(
.394(1) Å) and [Rh3(µ3-C7H4NS2)2(CO)2(PPh3)2(tfbb)]
(
22) Ciriano, M. A.; P e´ rez-Torrente. J . J .; Viguri, F.; Lahoz, F. J .;
Tiripicchio, A.; Tiripicchio-Camellini, M. J . Chem. Soc., Dalton Trans.
990, 1493.
23) Tauster, S. J . Acc. Chem. Res. 1987, 20, 389. Sakellson, S.;
2.374-2.383(6) Å).22 On the other hand, the Ti-S bond
distance observed, 2.3750(8) Å, is significantly longer
1
(
than that observed in the related [CpTi(µ3-S3){Rh-
McMillan, M.; Haller, G. L. J . Phys. Chem. 1986, 90, 1733.
(24) (a) Tejel, C.; Shi, Y.-M.; Ciriano, M. A.; Edwards, A. J .; Lahoz,
F. J .; Modrego, J .; Oro, L. A. J . Am. Chem. Soc. 1997, 119, 6678. (b)
Tejel, C.; Villoro, J . M.; Ciriano, M. A.; L o´ pez, J . A.; Eguiz a´ bal, E.;
Lahoz, F. J .; Bakhmutov, V. I.; Oro, L. A. Organometallics 1996, 15,
2967. (c) Ciriano, M. A.; P e´ rez-Torrente, J . J .; Lahoz, F. J .; Oro, L. A.
J . Chem. Soc., Dalton Trans. 1992, 1831.
tfbb)}3] (mean 2.295(3) Å)16 or in the cluster [{CpTi}2-
µ4-O)(µ3-S)4 {Rh4(CO)4(P(OPh)3)2}] (average 2.2693(10)
(
(
(21) P e´ rez-Torrente, J . J .; Casado, M. A.; Ciriano, M. A.; Lahoz, F.
J .; Oro, L. A. Inorg. Chem. 1996, 35, 1782.

Early-Late Heterobimetallic Complexes
Organometallics, Vol. 18, No. 25, 1999 5303
Sch em e 2
Ta ble 2. Selected Bon d Dista n ces (Å) a n d An gles
(
d eg) for Com p ou n d 8
Anionic Complex
3.0435(14)
Ir(1)‚‚‚Ir(2)
Ir(1)‚‚‚Ir(3)
3.1198(11)
2.362(3)
2.364(3)
Ir(2)‚‚‚Ir(3)
3.076(2)
2.360(3)
2.368(2)
2.358(2)
1.830(10)
1.844(10)
1.869(12)
1.147(11)
1.153(12)
1.133(12)
Ir(1)-S(1)
Ir(1)-S(2)
Ir(2)-S(1)
Ir(2)-S(2)
Ir(3)-S(1)
2.370(3)
Ir(3)-S(2)
Ir(1)-C(101)
Ir(2)-C(201)
Ir(3)-C(301)
C(101)-O(101)
C(201)-O(201)
C(301)-O(301)
1.842(11)
1.851(10)
1.854(10)
1.157(12)
1.135(11)
1.131(11)
Ir(1)-C(102)
Ir(2)-C(202)
Ir(3)-C(302)
C(102)-O(102)
C(202)-O(202)
C(302)-O(302)
Ir(2)‚‚‚Ir(1)‚‚‚Ir(3)
59.86(5) S(1)-Ir(1)-S(2)
82.53(9)
S(1)-Ir(1)-C(102) 174.4(3)
S(2)-Ir(1)-C(101) 174.3(3)
S(1)-Ir(1)-C(101)
Ir(1)‚‚‚Ir(2)‚‚‚Ir(3)
92.0(3)
61.30(2) S(1)-Ir(2)-S(2)
S(2)-Ir(1)-C(102)
92.0(3)
82.29(8)
S(1)-Ir(2)-C(202) 174.1(3)
S(2)-Ir(2)-C(201) 175.1(3)
S(2)-Ir(2)-C(202)
S(1)-Ir(2)-C(201)
Ir(1)‚‚‚Ir(3)‚‚‚Ir(2)
94.0(3)
58.84(5) S(1)-Ir(3)-S(2)
92.3(3)
82.39(9)
S(1)-Ir(3)-C(302) 173.2(3)
S(2)-Ir(3)-C(301) 175.8(3)
S(1)-Ir(3)-C(301)
93.6(3)
S(2)-Ir(3)-C(302)
91.0(3)
Cationic Complex
2.035(10)
Ti-Cp(1)a
Ti-O(1)
O(1)-C(2)
C(2)-C(3)
Ti-Cp(2)a
Ti-O(2)
2.034(10)
1.969(7)
1.295(11)
1.34(2)
X-ray diffraction study, and the structure is shown in
Figure 3.
1.981(6)
1.279(11)
1.40(2)
O(2)-C(4)
C(3)-C(4)
The ion-pair complexes 7 and 8 are 1:1 electrolytes
in acetone. The FAB+ mass spectra show the presence
a
a
a
Cp(1) -Ti-Cp(2)
133.8(4)
105.9(3)
106.1(3)
129.2(6)
122.0(10)
Cp(2) -Ti-O(1)
106.3(4)
108.0(4)
86.6(3)
128.4(7)
123.4(10)
+
a
a
of the cation [Cp2Ti(acac)] , and the corresponding
Cp(1) -Ti-O(1)
Cp(2) -Ti-O(2)
-
a
anions [M3(µ3-S)2(CO)6] are observed under FAB-
Cp(1) -Ti-O(2)
O(1)-Ti-O(2)
Ti-O(2)-C(4)
O(2)-C(4)-C(3)
Ti-O(1)-C(2)
conditions. Spectroscopic data for both complexes are
very similar and in agreement with the structure found
O(1)-C(2)-C(3)
1
a Cp(1) and Cp(2) represent the centroids of the two cyclopen-
tadienyl ligands (Cp(1), C(6)-C(10); Cp(2), C(11)-C(15)).
in the solid state for 8. The H NMR spectra show the
expected 2:1 ratio for the Cp:acac ligands, and the
chemical shifts of the Cp resonances closely resemble
those found for complexes 1-3, where an acac ligand is
also bonded to the titanium center. Moreover, the dCH
resonance of the acetylacetonate ligand in complexes 7
and 8 is observed at low field, in agreement with the
Str u ctu r e of [Cp 2Ti(a ca c)][Ir 3(µ3-S)2(CO)6] (8).
The molecular structure of the complex [Cp2Ti(acac)]-
Ir3(µ3-S)2(CO)6] (8) has been unambiguously determined
by X-ray crystallography on a single crystal obtained
by slow diffusion of n-hexane into a concentrated
solution of 8 in dichloromethane. The compound consists
[
+
electrophilic character of the cation [Cp2Ti(acac)] .
These values are only comparable to that observed in
the heterotrinuclear complex [Cp(acac)Ti(µ3-S)2{Rh-
+
of discrete mononuclear titanium cations [Cp2Ti(acac)]
-
and trinuclear iridium anions [M3(µ3-S)2(CO)6] (Figure
(
tfbb)}2] (2) containing π-acceptor tfbb ligands. Finally,
-
3). Selected bond distances and angles are summarized
in Table 2.
all the carbonyl ligands in the [M3(µ3-S)2(CO)6] anions
are equivalent, yielding a doublet at 184.9 ppm ( J Rh-C
1
The anion [Ir3(µ3-S)2(CO)6]- shows a triangular ar-
rangement of iridium atoms capped on each side by two
triply bridging sulfur atoms. Each iridium center dis-
plays a square-planar geometry by coordination to two
cis µ3-bridging sulfidos and two terminal carbonyl
groups. The structure of this anionic complex has been
previously reported forming part of the ionic compound
1
3
1
)
70 Hz) and a singlet at 174.7 ppm in the C{ H}
NMR spectra of complexes 7 and 8, respectively. In
addition, the 1H and C{ H} NMR spectra of both
13
1
complexes also show equivalent methyl and CO groups
of the acac ligand, as required by the Cs symmetry of
+
the [Cp2Ti(acac)] cation.
The anions [M3(µ3-S)2(CO)6]- (M ) Rh and Ir) have
been previously obtained by several methods and struc-
turally characterized by Garlaschelli et al.25 The deg-
radation of the clusters [M4(CO)12] and [M6(CO)16] with
KSCN and potassium polysulfide and the reaction of the
2
5a
[
NMe3(CH2Ph)][Ir3(µ3-S)2(CO)6]; in this salt, two struc-
turally different trinuclear anions were found in the
asymmetric unit: one anion with idealized D3h sym-
metry (Ir‚‚‚Ir 3.084-3.088(1) Å) and the second one in
which the symmetry is lowered to C2v due to the
shortening of two Ir‚‚‚Ir distances (3.064 and 3.065(1)
Å) and the lengthening of the remaining one (3.127(1)
Å). In 8, the three Ir‚‚‚Ir separations are statistically
different, spread out between 3.0435(14) and 3.1198-
-
anionic complexes [MCl2(CO)2] (M ) Rh, Ir) with
[N(PPh3)2]2S give both anions in yields ranging from 60
to 80%. [Cp2Ti(acac)]ClO4 was prepared by reaction of
Cp2TiCl2 with AgClO4 in water in the presence of
2
6
acetylacetone, probably via the intermediate species
(
11) Å, and reducing consequently to Cs, the symmetry
+
[
Cp2Ti(OH)] ; however, a crystal structure of compounds
of this anion in the solid state. As reported by Garl-
aschelli et al. in [NMe3(CH2Ph)][Ir3(µ3-S)2(CO)6],2
these intermetallic separations are clearly longer if
containing this cation has not been reported yet.
5a
(
25) (a) Pergola, R. D.; Garlaschelli, L.; Martinengo, L.; Demartin,
F.; Manassero, M.; Sansoni, M. J . Chem. Soc., Dalton Trans. 1986,
463. (b) Galli, D.; Garlaschelli, L.; Ciani, G.; Fumagalli, A.; Mar-
tinengo, S.; Sironi, A. J . Chem. Soc., Dalton Trans. 1984, 55.
2
(26) (a) Doyle, G.; Stuart, T. Inorg. Chem. 1968, 7, 2484. (b) Doyle,
G.; Tobias, R. S. Inorg. Chem. 1967, 6, 1111.

5
304 Organometallics, Vol. 18, No. 25, 1999
Casado et al.
compared with metal-metal bond distances observed
Sch em e 3
in tetra- or hexanuclear iridium carbonyl complexes
2
7
(
2.65-2.80 Å), but are short enough to be indicative
1
7,28
of weak intermetallic interactions.
On the other
hand, all the remaining Ir-S (mean 2.364(2) Å), Ir-C
mean 1.848(5) Å), and C-O (mean 1.143(5) Å) bond
(
distances are identical and compare well with values
reported previously.
Although a formal valence electron count would
-
render 48 e for the anionic complex and a consequent
saturated triangular metal cluster structure should be
formed, in light of the rather long Ir‚‚‚Ir separations this
anion would be better described as derived from three
-
1
6 e square-planar Ir(I) moieties sharing two cis S
atoms and having weak metal-metal interactions. From
the different Ir‚‚‚Ir separations observed, these non-
bonding interactions seem to be strongly dependent on
intermolecular factors and packing forces.25
Considering the Cp ring centroids and the two donor
atoms of the acetylacetonate ligand, the titanium ex-
hibits a distorted pseudotetrahedral coordination in the
+
cation [Cp2Ti(acac)] . The distortion around the metal
arises from the greater steric demand of the Cp ligands
compared to that of the acetylacetonate and the chelat-
ing nature of the latter ligand. Quite interesting to
comment are the differences observed in the titanium
coordination sphere between 1 and this cationic com-
plex. While the Ti-Cp(centroid) distances are identical
(
(
2.035(10) vs 2.060(3) Å) and the O-Ti-O rather similar
81.08(7)° vs 86.6(3)°), the Ti-O bond distances are
markedly different, 2.062(2) in 1 and 1.981(6) and 1.969-
7) in 8. Most likely the comparatively more electrophilic
1
(
complex 9, at δ 183.9 (d, J Rh-C ) 72 Hz) and 183.6 (d,
1
character of this cationic complex strengthens the
electronic donation of the acac ligand as evidenced by
the shorter Ti-O bond distances in the solid state or
by the displacement toward lower field of the dCH
J Rh-C ) 71 Hz). Complexes 9 and 10 display three
strong absorptions for terminal carbonyl groups in the
IR spectrum, in agreement with the local symmetry of
the molecular framework (“M2(µ-S)2(CO)4”, C2v); not-
withstanding, four distinct resonances should be ob-
served for the whole Cs symmetry. This observation has
1
resonance of this ligand in the solution H NMR spectra.
Ea r ly-La te Heter otr in u clea r Ca r bon yl Com -
p lexes. The heterobimetallic complexes [Cp(acac)Ti(µ3-
S)2{M(cod)}2] (M ) Rh (1) or Ir (2)) react with carbon
monoxide under atmospheric pressure, in dichoro-
methane, to give air-sensitive dark red solutions of the
complexes [Cp(acac)Ti(µ3-S)2{Rh(CO)2}2] (9) and [Cp-
8
8
already been found in related tetracarbonyl d -d
dinuclear complexes with bridging thiolate ligands in
which the number of absorptions in the IR spectrum is
explained by the local molecular symmetry.29
The related 8-oxyquinolinate heterotrinuclear com-
plexes [Cp(quinol)Ti(µ3-S)2{Rh(CO)2}2] (11) and [Cp-
(quinol)Ti(µ3-S)2{Ir(CO)2}2] (12) are obtained by carbo-
nylation of the diolefin complexes [Cp(quinol)Ti(µ3-
S)2{M(cod)}2] (4, 6) and isolated as air-sensitive black
microcrystalline solids in good yield. Both complexes
display the expected set of six resonances for the protons
(acac)Ti(µ3-S)2{Ir(CO)2}2] (10), respectively (Scheme 3).
These carbonyl complexes are isolated as fairly stable
black microcrystalline solids in high yield.
The observation of the molecular ions [Cp(acac)Ti(µ3-
+
+
S)2{Rh(CO)2}2] and [Cp(acac)Ti(µ3-S)2{Ir(CO)2}2] , at
m/z 594 and 774, respectively, in the FAB mass spectra,
confirms that the nuclearity is maintained upon carbo-
nylation. The available spectroscopic information indi-
cates that complexes 9 and 10 have Cs symmetry and
evidences that their structures are identical to those of
the parent diolefin complexes, replacing the diolefin
ligands with two carbonyl groups. As the carbonyl
ligands are related by symmetry, two distinct reso-
nances are observed in the 13C{ H} NMR spectrum of
1
of the 8-oxyquinolinate ligand in the H NMR spectrum
and the characteristic downfield-shifted resonance for
the cyclopentadienyl ligand. In addition both complexes
show three strong absorptions for terminal carbonyls
in the IR spectrum.
The reaction of [Cp(acac)Ti(µ -S) {Rh(CO) } ] (9) with
2 molar equiv of PPh3 gives the complex [Cp(acac)Ti-
3
2
2 2
1
(µ -S) {Rh(CO)(PPh )} ] (13) after evolution of carbon
3
2
3
2
monoxide (Scheme 3). The formation of the disubstituted
complex is observed in the FAB mass spectrum and also
(
27) (a) Garlaschelli, L.; Malatesta, M. C.; Martinengo, S.; Demartin,
F.; Manassero, M.; Sansoni, M. J . Chem. Soc., Dalton Trans. 1986,
77. (b) Demartin, F.; Manassero, M.; Sansoni, M.; Garlaschelli, L.;
Raimondi, C.; Martinengo, S. J . Organomet. Chem. 1983, 243, C10.
c) Ciani, G.; Sironi, A.; Chini, P.; Martinengo, S. J . Organomet. Chem.
981, 213, C37.
28) (a) Pinillos, M. T.; Elduque, A.; L o´ pez, J . A.; Lahoz, F. J .; Oro,
-1
7
in the IR spectrum, where the broad band at 1954 cm
is indicative of monosubstitution at each rhodium
(
1
2
1
center. Complex 13 is obtained as a 3:5 mixture of the
(
L. A. J . Chem. Soc., Dalton Trans. 1991, 1391. (b) Carmona, D.; Ferrer,
J .; Lahoz, F. J .; Oro, L. A.; Reyes, J .; Esteban, M. J . Chem. Soc., Dalton
Trans. 1991, 2811.
(29) (a) De Mountazon, D.; Kalck, P. Poilblanc, R. J . Organomet.
Chem. 1980, 186, 121. (b) Palyi, G.; Vizi-Oros, A.; Marko, L.; Marcati,
F.; Bor, G. J . Organomet. Chem. 1974, 66, 295.

Early-Late Heterobimetallic Complexes
Organometallics, Vol. 18, No. 25, 1999 5305
-
cis and trans isomers, as deduced from the integral of
dinuclear anion [Cp2Ti2(µ-S)2(S)2]2 and with [{Rh(µ-
1
the Cp resonances in the H NMR spectrum. The cis
OMe)(diolefin)}2] to give the compounds [CpTi{µ3-S)3-
{Rh(diolefin)}3]. All these reactions present as a
3
1
1
17
isomer displays two doublets in the P{ H} NMR
spectrum, while the trans isomer exhibits two doublets
of doublets, showing a J P-P of 9 Hz, a standard value
found for long P-P coupling in dinuclear complexes
common feature the removal of a cyclopentadienyl group
from the titanium as free cyclopentadiene. The differ-
ence is related to the fate of the resulting titanium
moiety, which dimerizes in the most simple case,
captures a chelating acac ligand, keeping the sulfido
groups, or increases the number of sulfido ligands along
with the corresponding M(diolefin) moieties.
To complete this general view, the results of some of
the reactions of Cp Ti(SH) with mononuclear rhodium
and iridium complexes are strongly dependent on the
3
0
having a mutual trans disposition.
The disubstituted iridium complex [Cp(acac)Ti(µ3-S)2-
Ir(CO)(PPh3)}2] (14) is obtained as an air-sensitive
{
violet solid by replacement of two carbonyl ligands by
PPh3 in the complex [Cp(acac)Ti(µ3-S)2{Ir(CO)2}2] (10).
As is found for the rhodium analogue, the synthesis is
not selective since a 1:1 ratio of the cis and trans isomers
2
2
3
1
8
is isolated. Both isomers are easily identified in the P-
ancillary ligands of the d metal centers, as shown by
those with [M(acac)(CO) ]. In these reactions the cyclo-
1
{
H} NMR spectrum since the cis isomer shows two
2
singlets, while two doublets (J P-P ) 7 Hz) are observed
for the trans isomer.
pentadienyl groups on the titanium atom are main-
tained while an acac group is added to form the cation
+
The related rhodium and iridium 8-oxyquinolinate
complexes [Cp(quinol)Ti(µ3-S)2{Rh(CO)(PPh3)}2] (15)
and [Cp(quinol)Ti(µ3-S)2{Ir(CO)(PPh3)}2] (16) are con-
veniently prepared by reaction of the corresponding
tetracarbonyl derivatives [Cp(quinol)Ti(µ3-S)2{M(CO)2}2]
[Cp Ti(acac)] . In addition, the sulfido ligands are
2
8
transferred to the d metal centers to form the homo-
trinuclear anions [M (µ -S) (CO) ] (M ) Rh and Ir).
These reactions leading to the ion-pair products [Cp2-
-
3
3
2
6
Ti(acac)][M (µ -S) (CO) ] are fast and clean processes,
3
3
2
6
(M ) Rh, 11; M ) Ir, 12) with 2 molar equiv of PPh3.
although they involve a tremendous ligand redistribu-
tion between rhodium (or iridium) and titanium. The
deprotonation of Cp Ti(SH) with [Rh(quinol)(CO) ] or
As is the case for the acac complexes, the formation of
both complexes is not selective since the expected four
isomers arising from the mutual disposition of the PPh3
ligands as well as their relative disposition to the
2
2
2
[Ir(quinol)(CO) ] also gives ion-pair products, but it
2
seems to follow a different path since a 2:3 mole ratio
of the reactants is necessary for the reaction to go to
8
-oxyquinolinate ligand are observed. The ratio between
1
the isomers is difficult to establish by H NMR spec-
troscopy, but the isomers can be distinguished in the
completion. Although the formation of both anions [M -
3
-
(µ -S) (CO) ] (M ) Rh, Ir) is observed, the cationic
3
2
6
3
1
1
P{ H} NMR spectrum. Thus, for complex 16 the two
species are not well-defined since the spectroscopic data
are inconclusive.
cis isomers display four singlets (two for each isomer),
and two doublets (J P-P ) 6-8 Hz) are observed for each
trans isomer.
Su lfid o Liga n d Tr a n sfer ver su s Cyclop en ta d i-
en e Elim in a tion . The formation of early-late hetero-
bimetallic complexes always competes with the ligand
Discu ssion
8
transfer of the potential bridging ligands to the d metal
centers. This is particulary frequent in the case of
thiolato ligands, so that some thiolate ligand transfer
reactions from thiolatotitanocene or thiolatozirconocene
complexes have been recently used to prepare the
corresponding thiolato complexes of the late transition
F or m a tion of th e Tr in u clea r Heter obim eta llic
0
8
d -d Com p lexes. Assuming the acidity of the hydro-
sulfido ligands in Cp2Ti(SH)2, the easy removal of
anionic ligands by protonation in rhodium and iridium
complexes such as [M(acac)(diolefin)], and the ability
of sulfido ligand to bridge several metals, an expected
outcome from the reactions between these compounds
would be a deprotonation of the first species followed
by the addition of two M(diolefin) fragments to give the
complexes [Cp2Ti(µ3-S)2{M(diolefin}2]. However, these
reactions are not so simple, although they proceed
cleanly to give the heterotrinuclear complexes [Cp(acac)-
Ti(µ3-S)2{M(diolefin}2] (M ) Rh, Ir) as the exclusive
products along with free Hacac and cyclopentadiene.
The formation of the new type of early-late compound
with [TiRh2] and [TiIr2] cores is a fast process, in which
no intermediates have been detected, involving a formal
replacement of a cyclopentadienyl group from the
titanium by a chelating acac ligand and the protons of
the hydrosulfido ligands by two M(diolefin) fragments.
The results from the reactions of Cp2Ti(SH)2 with the
N,O-chelating 8-oxyquinolinato complex [M(quinol)-
3
1
metals Co, Rh, Pd, and Pt. These ligand transfer
reactions are believed to proceed through an associative
pathway involving a heterobimetallic intermediate where
3
1b
the ligand redistribution takes place.
The difference in the reactions leading either to the
complexes [Cp(acac)Ti(µ3-S)2{M(diolefin)}2] or to the ion-
pair complexes [Cp2Ti(acac)][M3(µ3-S)2(CO)6] involves
the release of cyclopentadiene versus a sulfido ligand
transfer process. Notably, the fate of the reactions in
one or the other direction is dictated by the character
of the ancillary ligands on the mononuclear complexes,
since the sulfide transfer process is only observed for
the carbonyl case. A reliable approach to the formation
of both types of complexes is presented in Scheme 4,
which rationalizes the results. The reactions start with
(31) (a) Fandos, R.; MartinezRipoll, M.; Otero, A.; Ruiz, M. J .;
Rodriguez, A.; Terreros, P. Organometallics 1998, 17, 1465. (b)
Osakada, K.; Kawaguchi, Y.; Yamamoto, T. Organometallics. 1995, 14,
4542. (c) Huang, Y.; Drake, R. J .; Stephan, D. W. Inorg. Chem. 1993,
(
diolefin)] evidence that they proceed through an identi-
cal pathway.
3
2, 3022. (d) Boorman, P. M.; Freeman, G. K. W.; Parvez, M.
Closely related reactions are the monodeprotonation
Polyhedron 1992, 11, 765. (e) Wark, T. A.; Stephan, D. W.; Can. J .
Chem. 1990, 68, 565. (f) Huang, Y.; Drake, R. J .; Stephan, D. W. Inorg.
Chem. 1990, 29, 3622. (g) Shaver, A.; Morris, S.; Turrin, R.; Day, V.
W. Inorg. Chem. 1990, 29, 3622. (h) Bolinger, C. M.; Rauchfuss, T. B.
Inorg. Chem. 1982, 21, 3947.
1
5e
17
of Cp2Ti(SH)2 either by NaH
or by BuLi to give the
(30) J im e´ nez, M. V.; Sola, E.; L o´ pez, J . A.; Lahoz, F. J .; Oro, L. A.
Chem. Eur. J . 1998, 4, 1398.

5
306 Organometallics, Vol. 18, No. 25, 1999
Casado et al.
Sch em e 4
a first common step: the monodeprotonation of Cp2Ti-
SH)2 by 1 equiv of [M(acac)L2] (L2 ) diolefin or (CO)2),
as occurs when a strong base is used, to give the
intermediary species [Cp2Ti(µ-S)(µ-SH)ML2] (A) and free
acacH.
For the diolefinic complexes, this intermediate A could
react either with the Hacac present in the medium to
give the new heterodinuclear intermediate [Cp(acac)-
Ti(µ-S)(µ-SH)ML2] (B) or directly with [M(acac)(diole-
fin)] with transfer of the acac ligand from rhodium to
titanium and elimination of cyclopentadiene to give the
final products. Transfer of ligands between metals is a
well-documented reaction involving polynuclear inter-
mediates. In the first instance a further reaction with
a second equivalent of [M(acac)(diolefin)] should finally
produce the trinuclear complexes [Cp(acac)Ti(µ3-S)2-
of related dinuclear heterobimetallic complexes such as
[Cp2Ti(µ-SH)2Mo(CO)4], [Cp*2Zr(µ-S)2Rh(CO)2] , and
3
2
- 3d
(
tt
tt
[Cp 2Zr(µ-S)2{M(CO)2}2] (Cp ) 1,3-bis(tert-butyl)cy-
3
3
clopentadienyl).
The driving force for the ligand transfer from d to d8
can be attributed to the hard and soft mismatching
between the titanocene moiety and the bridging sulfide
0
3
4
ligand. However, it is well-known that the Lewis
acidity of the late transition metal centers in early-
late heterobimetallic thiolato complexes facilites the
Ti-S bond cleavage and consequently the ligand trans-
3
1c
fer process.
In the present case, the sulfido ligand
transfer could be a consequence of the instability of the
heterotrinuclear intermediate [Cp2Ti(µ3-S)2{M(CO)2}2]
probably due to the presence of the strong π-acceptor
carbonyl ligands.
As far as the cyclopentadiene elimination is con-
cerned, the simplest pathway consists of an intramo-
lecular proton transfer from the hydrosulfide ligand to
the cyclopentadienyl group in the dinuclear hydrosulfido
complex [Cp2Ti(µ-SH)(µ-S)Rh(diolefin)] (A) (Scheme 5).
This step is likely in the proposed deprotonation of Cp2-
Ti(SH)2 with [{Rh(µ-OMe)(diolefin)}2], for which this
{
M(diolefin)}2].
The reaction with Hacac is also open for the inter-
mediate [Cp2Ti(µ-S)(µ-SH)M(CO)2], but it would not
account for the results. Most probably, the deprotona-
tion of the hydrosulfide ligand with [M(acac)(CO)2] to
give the heterotrinuclear complex [Cp2Ti(µ3-S)2{ML2}2]
(C) occurs. As the formation of C competes with the
1
7
intermediate A was also proposed. Nevertheless, this
intermediate A is susceptible to the attack at the
titanium center by protonic nucleophiles in the reaction
medium such as methanol, water, and Hacac. A further
transfer of the proton on the nucleophile to the Cp ring
would also produce the elimination of cyclopentadiene
in all these processes (pKa(Hacac) ) 9.0; pKa(HCp) )
cyclopentadiene elimination, this step is crucial to
produce the difference between both types of reactions.
The strong π-acceptor ligands on the d8 center in A
should disfavor the cyclopentadiene elimination, while
they promote the deprotonation of the hydrosulfido
ligand by [M(acac)(CO)2]. A further reaction of this
species with the outcoming Hacac would degrade the
heterotrinuclear structure via Ti-S bond cleavage to
give the cation [Cp2Ti(acac)] , and the probable anionic
dinuclear species [M2(µ-S)(µ-SH)(CO)4] is deprotonated
1
5.0). Moreover, this most probable alternative pathway
+
would explain the bonding of the nucleophile (acac) to
the titanium center and the sensitivity of these reactions
-
1
8
to the reaction medium. Indeed, the removal of a
cyclopentadienyl ligand by electrophilic attack is a well-
by the third equivalent of [M(acac)(CO)2] to give the
anion [M3(µ3-S)2(CO)6] observed in the final product.
-
3
5
documented process.
Although
the
compounds
[Cp(acac)Ti(µ3-S)2-
{
M(diolefin)}2] could be also formed from an intermedi-
(32) Ruffing, C. J .; Rauchfuss, T. B. Organometallics 1985, 4, 524.
33) Hernandez-Gruel, M. A. F.; P e´ rez-Torrente, J . J .; Ciriano, M.
A.; Lahoz, F. J .; Oro, L. A. Angew. Chem., Int. Ed. 1999, 38, 2769.
34) Holland, P. L.; Andersen, R. A.; Bergman, R. G. Organometallics
1998, 17, 433.
(
ary species such as C with L2 ) diolefin, the reaction of
C with Hacac is unlikely for steric reasons. The proposal
of the species A and C is consistent with the existence
(

Early-Late Heterobimetallic Complexes
Organometallics, Vol. 18, No. 25, 1999 5307
Sch em e 5
Con clu d in g Rem a r k s
The deprotonation of Cp2Ti(SH)2 with mononuclear
rhodium and iridium complexes containing anionic
ligands has proved to be a convenient synthetic route
0
8
for the construction of new d -d early-late heterotri-
nuclear complexes having [TiRh2], [TiIr2], [TiRh3], and
[TiIr3] cores. The ancillary ligands on the mononuclear
complexes (diolefin versus carbonyl) play a key role in
the outcome of the reactions, since the heterobimetallic
complexes result for the former, while the transfer of
the sulfido ligands occurs for the latter. In addition, the
products from the additive-deprotonation of Cp2Ti(SH)2
are strongly dependent on the anionic ligand in the
starting rhodium and iridium complexes (methoxide
versus acetylacetonate), which in turn control the nucle-
arity of the early-late complexes.
Exp er im en ta l Section
Gen er a l Meth od s. All manipulations were performed
under an inert atmosphere (nitrogen or argon) using Schlenk-
tube techniques. Solvents were dried by standard methods and
distilled under nitrogen immediately prior to use. Molecular
weights were determined with a Knauer osmometer using
chloroform solutions. Carbon, hydrogen, and nitrogen analyses
were performed in a Perkin-Elmer 2400 microanalyzer. IR
-
1
spectra were recorded with a Nicolet-IR 550 (4000-400 cm
)
spectrophotometer with the bands calibrated against the sharp
peak (1601.4 cm ) of a polystyrene film. Mass spectra were
recorded in a VG Autospec double-focusing mass spectrometer
-
1
Rep la cem en t Rea ction s. Although the carbonyl
complexes [Cp(acac)Ti(µ3-S)2{M(CO)2}2] are not acces-
sible by the direct reaction of the complexes [M(acac)-
1
13
1
31
1
operating in the FAB mode. H, C{ H}, and P{ H} NMR
spectra were recorded on Varian spectrometers operating at
1
2
99.95 and 300.13 MHz for H. Chemical shifts are referenced
(CO)2] with Cp2Ti(SH)2, they can be isolated by carbo-
4 3 4
to SiMe and H PO .
nylation of any of the diolefin complexes [Cp(acac)Ti(µ3-
S)2{M(diolefin)}2]. In the same way, the tetracarbonyl
complexes [Cp(quinol)Ti(µ3-S)2{M(CO)2}2] are obtained
by carbonylation of the heterotrinuclear diolefin com-
plexes under atmospheric pressure.
The heterotrinuclear core [TiM2] in the carbonyl
complexes is maintained upon replacement of two
carbonyls ligands by triphenyphosphine. However, the
reactions are not stereoselective since the complexes
Sta r tin g Ma ter ia ls. Standard procedures were used to
prepare the rhodium37 and iridium acetylacetonate complexes
[
(
2
Rh(acac)(cod)], [Rh(acac)(tfbb)], [Rh(acac)(CO) ], [Rh(acac)-
CO)(PPh )], [Ir(acac)(cod)], and [Ir(acac)(CO) ]. The 8-ox-
3 2
38
39
yquinolate complexes [Rh(quinol)(cod)], [Rh(quinol)(tfbb)], [Ir-
(quinol)(cod)], [Rh(quinol)(CO) ], and [Ir(quinol)(CO) ] were
prepared according to the previously reported method. Cp
2
2
4
0
2
-
3
2
Ti(SH)
Syn th esis of th e Com p lexes. [Cp (a ca c)Ti(µ
cod )} ] (1). Cp Ti(SH) (0.196 g, 0.806 mmol) was added to a
2
was prepared following the literature procedure.
3
-S) {Rh -
2
(
2
2
2
[Cp(acac)Ti(µ3-S)2{M(CO)(PPh3)}2] are obtained as a
solution of [Rh(acac)(cod)] (0.500 g, 1.612 mmol) in toluene (6
mL). The resulting violet solution was stirred for 30 min to
give a violet microcrystalline solid, which was filtered, washed
with hexane, and dried under vacuum (0.425 g). The filtrate
was concentrated under vacuum, and then hexane (5 mL) was
added to give an additional fraction. Yield (overall): 0.500 g
(89%). Anal. Calcd for C H O Rh S Ti (%): C, 44.72; H, 5.19.
cis/ trans mixture of isomers (M ) Rh, 5:3; M ) Ir, 1:1).
Interestingly, an identical isomer ratio for the rhodium
complex is observed when the synthesis is carried out
directly from [Rh(acac)(CO)(PPh3)] and Cp2Ti(SH)2. The
lack of stereoselectivity is also observed in the synthesis
of the complexes [Cp(quinol)Ti(µ3-S)2{M(CO)(PPh3)}2],
which are obtained as a mixture of four isomers. The
reactivity of the heterotrinuclear carbonyl complexes is
2
6
36
2
2
2
+
Found: C, 44.36; H, 4.90. MS (FAB+, CH
2
Cl
2
, m/z): 599 (M
+
- acac, 70), 487 (M - acac - cod, 60). Mol Weight. Found:
690 (calcd 698). 1H NMR (CDCl , 293 K): 6.53 (s, 5H, Cp),
8
8
closely related to the d -d dinuclear thiolato complexes
{M(µ2-SR)(CO)(PPh3)}2] (M ) Rh and Ir), where the
3
5
2
2
{
.70 (s, 1H, CH, acac), 4.64 (m, 2H), 4.40 (m, 2H), 4.31 (m,
[
H), 4.23 (m, 2H) (dCH, cod), 2.56 (m, 2H), 2.10-2.19 (m, 8H),
disubstituted complexes are also isolated as the cis/
trans isomer mixture.36 The lack of selectivity in these
substitution processes contrasts with that observed for
other di- and tetranuclear complexes supported by N,S-
donor ligands, where the preferential substitution of the
1
3
.02-1.96 (m, 6H) (>CH
2
, cod), 2.00 (s, 6H, CH
3
, acac). C-
1
H} NMR (CDCl
3
, 293 K): 188.8 (CO, acac), 114.6 (Cp), 102.6
(CH, acac), 81.9 (d, J Rh-C ) 11 Hz), 80.9 (d, J Rh-C ) 10 Hz),
8
3
0.4 (d, J Rh-C ) 11 Hz), 79.1 (d, J Rh-C ) 11 Hz) (dCH, cod),
2.3, 31.7, 31.4, 30.9 (>CH , cod), 26.2 (CH , acac).
[Cp (a ca c)Ti(µ -S) {Rh (tfbb)} ] (2) was obtained as a beige
2
3
2
1
carbonyls trans to sulfur is observed.
3
2
2
microcrystalline solid by reaction of [Rh(acac)(tfbb)] (0.200 g,
(
35) (a) Lucas, C. R.; Gabe, E. J .; Lee, F. L. Can. J . Chem. 1988, 66,
29. (b) Choquette, D. H.; Buschmann, W. E.; Graceffa, R. F.; Planalp,
R. P. Polyhedron 1995, 14, 2569.
36) (a) Poilblanc, R. Inorg. Chim. Acta 1982, 62, 75. (b) Bonnet, J .
J .; Thorez, A.; Maisonnat, A.; Galy, J .; Poilblanc, R. J . Am. Chem. Soc.
1
1
4
(37) Bonati, F.; Wilkinson, G. J . Chem. Soc. 1964, 3156.
(38) Robinson, S. R.; Shaw, B. L. J . Chem. Soc. 1965, 4997.
(39) Pitt, C. G.; Monteith, L. K.; Ballard, L. F.; Collman, J . P.;
Morrow, J . C.; Roper, W. R.; Ulk, D. J . Am. Chem. Soc. 1966, 88, 4286.
(40) Ugo, R.; La Monica, G.; Cenini, S.; Bonati, F. J . Organomet.
Chem. 1968, 11, 159.
(
979, 101, 5940. (c) Bonnet, J . J .; Kalck, P.; Poilblanc, R. Inorg. Chem.
977, 16, 1514.

5
0
308 Organometallics, Vol. 18, No. 25, 1999
.467 mmol) and Cp Ti(SH) (0.057 g, 0.234 mmol) following
Casado et al.
2
2
Workup as above gave the complex as a dark gray solid.
the procedure described above. Yield: 0.189 g (87%). Anal.
Calcd for C34 Rh Ti (%): C, 43.71; H, 2.59. Found:
C, 43.67; H, 2.55. H NMR (CDCl , 223 K): 6.72 (s, 5H, Cp),
.15 (s, 1H, CH, acac), 5.78 (m, 1H), 5.40 (m, 2H), 5.23 (m,
H) (CH, tfbb), 4.43 (m, 2H), 4.06 (m, 2H), 3.94 (m, 4H) (d
Yield: 0.075 g (72%). Anal. Calcd for C30
39.08; H, 3.83; N, 1.52. Found: C, 38.91; H, 3.61; N, 1.55. MS
2 2
H35Ir NOS Ti (%): C,
H
24
F
8
1
O
2
2 2
S
+
+
3
(FAB+, CH
2
Cl
2
, m/z): 921 (M , 70), 855 (M - Cp, 70), 808
+
+
+
6
1
(M - cod, 40), 775 (M - quinol, 55), 744 (M - cod - Cp,
+
+
1
47), 705 (M - 2cod, 45), 665 (M - cod - quinol, 50). H NMR
1
3
1
2
4
6
CH, tfbb), 2.14 (s, 6H, CH
3
, acac). C{ H} NMR (CDCl
3
, 223
(CDCl
3
3
, 293 K): 8.77 (dd, H ), 8.22 (dd, H ), 7.47 (dd, H ), 7.28
5
7
K): 189.3 (CO, acac), 139.3 (dm, J C-F ) 241 Hz), 138.0 (dm,
(dd, H ), 7.02 (dd, H ), 6.91 (dd, H ) (J 2-3 ) 4.9 Hz, J 2-4 ) 1.3
Hz, J 3-4 ) 8.2, J 5-6 ) 8.0 Hz, J 5-7 ) 0.9 Hz and J 6-7 ) 7.9)
(quinol), 6.51 (s, 5H, Cp), 4.36 (m, 3H), 4.12 (m, 1H), 4.00 (m,
1H), 3.94 (m, 1H), 3.82 (m, 1H), 2.79 (m, 1H) (dCH, cod), 2.47
(m, 3H), 2.00 (m, 2H), 1.75 (m, 6H), 1.45 (m, 2H), 1.20 (m,
J
C-F ) 250 Hz) (CF, tfbb), 128.8 (br), 128.6 (br), 128.3 (br),
28.0 (br) (tfbb), 115.5 (Cp), 103.6 (CH, acac), 59.4 (d, J Rh-C
1
8
J
)
Hz), 59.0 (d, J Rh-C ) 10 Hz), 58.9 (d, J Rh-C ) 9 Hz), 58.6 (d,
Rh-C ) 9 Hz) (dCH, tfbb), 41.7, 40.8, 40.3, 40.0 (CH, tfbb),
2
5.1 (CH
Cp (a ca c)Ti(µ
microcrystalline solid from [Ir(acac)(cod)] (0.200 g, 0.501 mmol)
and Cp Ti(SH) (0.061 g, 0.250 mmol) following the procedure
described above. Yield: 0.192 g (87%). Anal. Calcd for C26
Ir Ti (%): C, 35.61; H, 4.14. Found: C, 35.44; H, 3.94.
MS (FAB+, CH
3
, acac).
1H), 1.05 (m, 1H), 0.35 (m, 1H) (>CH
Cp Ti(a ca c)][Rh (µ -S) (CO) ] (7). The addition of Cp
Ti(SH) (0.063 g, 0.258 mmol) to a solution of [Rh(acac)(CO)
2
, cod).
[
2
3
3
2
6
2
2
-
]
[
3 2 2
-S) {Ir (cod )} ] (3) was prepared as a gray
2
(0.200 g, 0.775 mmol) in dichloromethane (10 mL) gave a dark
2
2
red solution, which turned brown in 30 min. Concentration of
the solution to ca. 1 mL and slow addition of hexane gave the
compound as a brown microcrystalline solid, which was
filtered, washed with hexane, and dried under vaccum. Yield:
36
H -
2
2 2
O S
+
+
2
Cl
Cl , 293 K): 6.52 (s, 5H, Cp), 5.85 (s, 1H, CH,
acac), 4.37 (m, 2H), 3.90 (m, 6H) (dCH, cod), 2.00 (s, 6H, CH
2
, m/z): 876 (M , 55), 776 (M - acac, 40).
1
H NMR (CD
2
2
0
17 8 3 2
.197 g (93%). Anal. Calcd for C21H O Rh S Ti (%): C, 30.83;
3
3
,
,
1
3
1
H, 2.09. Found: C, 30.87; H, 1.93. MS (FAB+, CH
2
Cl
2
, m/z):
2
acac), 2.10-1.70 (m, 16H, >CH , cod). C{ H} NMR (CDCl
+
-
-
2
-
77 (M , 35). MS (FAB-, CH
2
Cl
2
, m/z): 541 (M , 35), 513 (M
2
(
(
93 K): 188.6 (CO, acac), 115.4 (Cp), 103.1 (CH, acac), 66.2
br), 64.7 (br) (dCH, cod), 33.7 (br), 32.7 (br), 32.0 (br), 31.5
br) (>CH , cod), 31.5 (CH , acac).
Cp (q u in ol)Ti(µ -S) {R h (cod )}
0.200 g, 0.583 mmol) was reacted with Cp
.291 mmol) in dichloromethane (10 mL) to give a purple
-
-
-1
CO, 15), 485 (M - 2CO, 7), 457 (M - 3CO, 7). Λ
M
(Ω
cm2 mol ): 134 (acetone, 4.89 × 10 M). H NMR (CD
-1
-4
1
2
2
Cl ,
2
3
2
CH
93 K): 6.67 (s, 10H, Cp), 6.18 (s, 1H, CH acac), 2.29 (s, 6H,
[
3
2
2
] (4). [Rh(quinol)(cod)]
Ti(SH) (0.071 g,
, acac). 13C{ H} NMR (CD
1
Cl
, 293 K): 195.7 (CO, acac),
3
2
2
(
0
2
2
1
3
84.9 (d, J Rh-C ) 70 Hz, CO), 122.1 (Cp), 106.8 (CH), 26.8 (CH )
-
1
(
acac). IR (CH
Cp Ti(a ca c)][Ir
red solid by reaction of [Ir(acac)(CO)
with Cp Ti(SH) (0.035 g, 0.144 mmol) in dichloromethane
following the procedure described above. Yield: 0.144 g (92%).
2
Cl
2
, cm ): ν(CO), 2029 (s), 1977 (s).
(µ -S) (CO) ] (8) was obtained as a dark
] (0.150 g, 0.432 mmol)
solution. This solution was stirred for 1 h and then concen-
trated under vaccum to ca. 1 mL. Slow addition of hexane gave
the compound as a violet solid, which was filtered, washed with
hexane, and dried under vaccum. Yield: 0.188 g (87%). Anal.
[
2
3
3
2
6
2
2
2
2 2
Calcd for C30H35NORh S Ti (%): C, 48.46; H, 4.74; N, 1.88.
Anal. Calcd for C21
H
17Ir
3
O
8
S
2
Ti (%): C, 23.22; H, 1.58.
Found: C, 48.15; H, 4.90; N, 1.90. MS (FAB+, CH
2
Cl
2
, m/z):
+
Found: C, 23.15; H, 1.42. MS (FAB+, CH
2
Cl
2
, m/z): 277 (M ,
+
+
+
+
7
43 (M , 100), 678 (M - Cp, 25), 635 (M - cod, 35), 527 (M
-
-
3
1
5). MS (FAB-, CH
2
Cl
2
, m/z): 809 (M , 100), 781 (M - CO,
1
2
-
3
2cod, 65). H NMR (CDCl , 293 K): 8.80 (dd, H ), 8.18 (dd,
-
-
(Ω-1 cm
2
5), 752 (M - 2CO, 5), 724 (M - 3CO, 10). Λ
M
4
6
3
5
7
H ), 7.46 (dd, H ), 7.28 (dd, H ), 7.01 (dd, H ), 6.94 (dd, H )
2-3 ) 4.9 Hz, J 2-4 ) 1.3 Hz, J 3-4 ) 8.2, J 5-6 ) 8.0 Hz, J 5-7
mol ): 128 (acetone, 5.03 × 10 M). 1H NMR (acetone-d
-
1
-4
,
6
(J
)
2
CH
93 K): 6.89 (s, 10H, Cp), 6.35 (s, 1H, CH, acac), 2.30 (s, 6H,
0
4
2
.7 Hz and J 6-7 ) 7.8) (quinol), 6.53 (s, 5H, Cp), 4.77 (m, 2H),
.65 (m, 1H), 4.45 (m, 1H), 4.32 (m, 3H), 3.29 (m, 1H) (dCH),
, acac). 13C{ H} NMR (acetone-d
1
, 293 K): 196.5 (CO, acac),
3
6
1
3 2
74.7 (CO), 123.7 (Cp), 107.3 (CH), 26.8 (CH ) (acac). IR (CH -
1
3
1
.54-1.25 (m, 16H, >CH
2
) (cod). C{ H} NMR (CDCl
3
, 293
-1
Cl , cm ): ν(CO), 2024 (s), 1969 (s).
2
K): 165.0, 149.8, 143.6, 137.5, 130.8, 130.4, 121.0 (quinol),
[
Cp (a ca c)Ti(µ
bubbled through a solution of [Cp(acac)Ti(µ
0.100 g, 0.143 mmol) in dichloromethane (10 mL) to give a
3
-S)
2
{Rh (CO)
2
}
2
] (9). Carbon monoxide was
1
8
3
14.4 (Cp), 112.0, 111.4 (quinol), 85.6 (br), 83.2 (br), 81.7 (br),
1.6 (br), 80.5 (br), 79.7 (br), 79.1 (br) (dCH, cod), 31.7 (br),
3
-S) {Rh(cod)} ] (1)
2
2
(
1.0 (s), 30.7 (s) (>CH
Cp (qu in ol)Ti(µ -S)
violet microcrystalline solid by reaction of [Rh(quinol)(tfbb)]
0.200 g, 0.423 mmol) with Cp Ti(SH) (0.052 g, 0.211 mmol)
in dichloromethane (10 mL) following the procedure described
above. Yield: 0.170 g (82%). Anal. Calcd for C38 NORh
2
, cod).
dark red solution in 5 min. Bubbling was maintained in order
to concentrate the solution to ca. 2 mL. Addition of hexane (5
mL) gave a black microcrystalline solid, which was isolated
by filtration, washed with hexane, and then vacuum-dried.
[
3
2
{Rh (tfbb)}
2
] (5) was obtained as a
(
2
2
Yield: 0.075 g (88%). Anal. Calcd for C14
H
12
O
6
Rh
2
S
2
Ti (%): C,
Cl
H
23
F
8
2
S
2
-
2
8.59; H, 2.06. Found: C, 28.33; H, 2.02. MS (FAB+, CH
2
2
,
Ti (%): C, 46.40; H, 2.37; N, 1.43. Found: C, 46.48; H, 1.83;
+
+
+
m/z): 594 (M , 30), 566 (M - CO, 35), 538 (M - 2CO, 40),
5
2
+
+
N, 1.42. MS (FAB+, CH
2
Cl
2
, m/z): 979 (M , 65), 914 (M
-
+
+
1
10 (M - 3CO, 34), 482 (M - 4CO, 100). H NMR (CDCl
93 K): 6.68 (s, 5H, Cp), 5.96 (s, 1H, CH), 2.07 (s, 6H, CH
3
,
+
+
+
Cp, 25), 836 (M - quinol, 10), 753 (M - tfbb, 55), 527 (M
2tfbb, 70), 462 (M - 2tfbb - Cp, 45). H NMR (CDCl
K): 8.67 (dd, H ), 8.32 (dd, H ), 7.69 (dd, H ), 7.32 (dd, H ),
.27 (d, H ), 7.14 (d, H ) (J 2-3 ) 4.9 Hz, J 2-4 ) 1.1 Hz, J 3-4
.2, J 5-6 ) 7.9 Hz and J 6-7 ) 7.8) (quinol), 6.75 (s, 5H, Cp),
.78 (m, 1H, CH), 5.43 (m, 1H, CH), 5.30 (m, 1H, CH), 4.54
3
)
+
1
-
3
, 293
13
1
(
(
(
acac). C{ H} NMR (CDCl
d, J Rh-C ) 72 Hz, CO), 183.6 (d, J Rh-C ) 71 Hz, CO), 118.4
3 2 2
Cp), 105.9 (CH, acac), 25.8 (CH , acac). IR (CH Cl , cm ):
3
, 293 K): 189.9 (CO, acac), 183.9
2
4
6
3
5
7
7
9
5
)
-1
ν(CO), 2066 (s), 2044 (s), 1998 (s); ν(CO, acac), 1558 (s), 1528
(s).
(br s, 2H, dCH), 4.40 (br s, 1H, dCH), 4.02 (br s, 2H, dCH),
[
Cp (a ca c)Ti(µ
microcrystalline solid by carbonylation of [Cp(acac)Ti(µ
Ir(cod)} ] (3) (0.220 g, 0.251 mmol) in dichloromethane
following the procedure described above. Yield: 0.169 g (87%).
3
-S)
2
{Ir (CO)
2
}
2
] (10) was obtained as a black
3
2
1
.91 (br s, 1H, dCH), 3.86 (br s, 1H, dCH), 3.44 (m, 1H, CH),
3
-S) -
2
.63 (br s, 1H, dCH) (tfbb). 13C{ H} NMR (CDCl
1
, 293 K):
3
{
2
64.6 (quinol), 150.2 (br), 150.1 (br) (tfbb), 143.7, 140.3, 140.0
(
quinol), 139.7 (dm, J C-F ) 248 Hz), 138.6 (dm, J C-F ) 249
Hz) (tfbb), 131.1, 130.6 (quinol), 128.6 (br), 128.3 (br) (tfbb),
21.0 (quinol), 115.9 (Cp), 112.6, 112.5 (quinol), 64.7 (br), 61.8
br), 61.5 (br), 60.5 (br), 59.5 (br), 59.0 (br), 58.5 (br) (dCH,
tfbb), 41.2, 40.8, 40.4, 40.1 (CH, tfbb).
Cp (qu in ol)Ti(µ -S) {Ir (cod )} ] (6). [Ir(quinol)(cod)] (0.100
g, 0.225 mmol) was reacted with Cp Ti(SH) (0.027 g, 0.112
mmol) in dichloromethane (10 mL) to give a dark solution.
Anal. Calcd for C14
H
12Ir
2
O
6
S
2
Ti (%): C, 21.86; H, 1.57.
+
Found: C, 21.78; H, 1.48. MS (FAB+, CH
2
Cl
2
, m/z): 774 (M ,
1
(
+
+
+
4
1
5), 716 (M - 2CO, 25), 690 (M - 3CO, 10), 660 (M - 4CO,
1
2). H NMR (CDCl
3
, 293 K): 6.75 (s, 5H, Cp), 6.05 (s, 1H,
-1
3 2 2
CH), 2.09 (s, 6H, CH ) (acac). IR (CH Cl , cm ): ν(CO), 2056
[
3
2
2
(s), 2031 (s), 1983 (s); ν(CO, acac), 1553 (s), 1530 (s).
[Cp (qu in ol)Ti(µ -S) {Rh (CO) ] (11). Carbon monoxide
was bubbled through a dichloromethane solution (10 mL) of
2
2
3
2
2 2
}

Early-Late Heterobimetallic Complexes
Cp(quinol)Ti(µ -S) {Rh(cod)} ] (4) (0.100 g, 0.134 mmol) to give
a violet solution. The solution was concentrated under carbon
monoxide to ca. 1 mL, and then hexane (5 mL) was added.
The black solid was collected by filtration, washed with hexane,
and then dried under vacuum. Yield: 0.067 g (78%). Anal.
Organometallics, Vol. 18, No. 25, 1999 5309
[
3
2
2
Ta ble 3. Cr ysta llogr a p h ic Da ta for Com p lexes 1
a n d 8
1
8
chem formula
fw
C26H36O2Rh2S2Ti
698.39
C21H17Ir3O8S2Ti
1085.97
Calcd for C18
5 2 2
H11NO Rh S Ti (%): C, 33.83; H, 1.73; N, 2.19.
cryst size, mm
cryst syst
space group
a, Å
0.41 × 0.33 × 0.33
orthorhombic
Pnma (no. 62)
17.593(2)
11.6592(7)
12.9790(10)
90.0
0.23 × 0.16 × 0.11
monoclinic
P21/n (no. 14)
9.379(3)
14.912(8)
18.946(5)
93.39(7)
1
Found: C, 33.65; H, 1.56; N, 2.15. H NMR (CDCl
3
3
, 293 K):
2
4
6
8
.81 (d, H ), 8.34 (d, H ), 7.55 (dd, H ), 7.48 (dd, H ), 7.22 (d,
5
7
H ), 6.99 (d, H ) (J 2-3 ) 4.9 Hz, J 3-4 ) 8.1, J 5-6 ) 7.9 Hz
-
1
and J 6-7 ) 7.8) (quinol), 6.62 (s, 5H, Cp). IR (CH
ν(CO), 2069 (s), 2047 (vs), 2004 (vs).
2
Cl
2
, cm ):
b, Å
c, Å
â, deg
[
Cp (qu in ol)Ti(µ
black microcrystalline solid by carbonylation of [Cp(quinol)-
Ti(µ -S) {Ir(cod)} ] (6) (0.100 g, 0.108 mmol) in dichlo-
romethane following the procedure described above. Yield:
.066 g (74%). Anal. Calcd for C18 NO Ti (%): C, 26.44;
H, 1.36; N, 1.71. Found: C, 26.32; H, 1.31; N, 1.68. MS (FAB+,
3 2 2 2
-S) {Ir (CO) } ] (12) was obtained as a
V, Å3
2662.3(4)
4
2645.1(18)
4
Z
3
2
2
-
3
Fcalcd, g cm
µ, mm
1.742
2.727
-1
1.696
15.536
0
H
11Ir
2
5 2
S
no. of measd reflns
no. of unique reflns
2681 (2θ e 50°)
5487 (2θ e 50°)
2466 (Rint ) 0.0215) 4682 (Rint ) 0.0309)
+
+
+
CH
2
Cl
2
, m/z): 820 (M , 8), 789 (M - CO, 10), 734 (M - 3CO,
min, max trasm fact 0.752, 0.894
no. data/restraints/ 2465/0/189
params
0.153, 0.429
4677/0/322
+
1
2
7
8
), 705 (M - 4CO, 12). H NMR (CDCl
3
, 293 K): 8.73 (d, H ),
4
6
3
5
.39 (d, H ), 7.58 (dd, H ), 7.51 (dd, H ), 7.27 (d, H ), 6.98 (d,
2
2
a
7
R(F) (F g 2σ(F ))
0.0230
0.0620
0.0346
0.0679
H ) (J 2-3 ) 4.9 Hz, J 3-4 ) 8.12, J 5-6 ) 8.1 Hz and J 6-7 ) 7.8)
2
b
-
1
wR(F ) (all data)
(
quinol), 6.75 (s, 5H, Cp). IR (CH
035 (vs), 1987 (vs).
Cp(acac)Ti(µ -S)
PPh (0.044 g, 0.168 mmol) was added to a solution of [Cp-
acac)Ti(µ -S) {Rh(CO) ] (9) (0.050 g, 0.084 mmol) to give a
2 2
Cl , cm ): ν(CO), 2058 (s),
a
2
R(F) ) ∑||Fo| - |Fc||/∑|Fo| for 2261 (1) or 3433 (8) observed
b 2 2 2 2 2 2 1/2 -1
[
3
2
{Rh (CO)(P P h
3
)}
2
] (13). Method A: Solid
reflections. wR(F ) ) [∑[w(Fo - Fc ) ]/∑[w(Fo ) ]] ; w
)
2
2
2
[
σ (Fo ) + (aP) + bP] (a ) 0.0276, b ) 4.3535 (1) and a ) 0.0267,
3
2 2
b ) 0.3735 (8)), where P ) [max(Fo , 0) + 2Fc )]/3.
(
3
2
2 2
}
violet solution and evolution of carbon monoxide. The solution
was stirred for 30 min and the solvent removed under vacuum
to give a violet residue, which was washed with cold hexane
and dried under vacuum. Yield: 0.075 g (84%). Method B: [Rh-
(CDCl
Hz), 35.8 (d, J Rh-P ) 162 Hz), 35.2 (d, J Rh-P ) 165 Hz) (cis
isomers); 36.8 (d of m, J Rh-P ) 168 Hz), 36.3 (d of m, J Rh-P
, cm-1):
68 Hz, J P-P ) 10 Hz) (trans isomers). IR (CH Cl
ν(CO), 1958 (vs).
Cp (qu in ol)Ti(µ
as a dark brown solid by reaction of [Cp(quinol)Ti(µ
3
, 293 K): 37.4 (d, J Rh-P ) 168 Hz), 36.2 (d, J Rh-P ) 166
)
(
acac)(CO)(PPh
Ti(SH) (0.019 g, 0.077 mmol) in dichloromethane to give a
violet solution. Workup as above gave the complex as a violet
solid. Yield: 0.067 g (82%). Anal. Calcd for C48 Rh
Ti (%): C, 54.25; H, 3.98. Found: C, 54.20; H, 3.87. MS (FAB+,
3 2
)] (0.076 g, 0.154 mmol) was reacted with Cp -
1
2
2
2
[
3
-S)
2
{Ir (CO)(P P h
3
)}
2
] (16) was obtained
-S) {Ir-
H
42
O
4
P
2
2 2
S -
3
2
+
+
(CO)} ] (12) (0.100 g, 0.122 mmol) with PPh3 (0.064 g, 0.244
CH
9
4
2
Cl
2
, m/z): 963 (M - acac, 25), 935 (M - CO - acac, 15),
2
+
+
mmol) in dichloromethane (10 mL) following the procedure
described above. Yield: 0.133 g (85%). Anal. Calcd for C52H -
41
07 (M - 2CO - acac, 57), 673 (M - 2CO - PPh
3
- acac,
), 6.33 (s,
), 2.03 (s, CH ), 1.96
) (acac) (two isomers). P{ H} NMR
, 293 K): 38.5 (d, J Rh-P ) 169 Hz), 33.6 (d, J Rh-P ) 164
1
3). H NMR (CDCl
3
, 293 K): 7.77-7.13 (m, PPh
3
Cp), 6.30 (s, Cp), 5.59 (s, CH), 2.09 (s, CH
(
(
3
3
Ir
2
NO
3
P
2
S
2
Ti (%): C, 48.56; H, 3.21; N, 1.09. Found: C, 48.32;
3
1
1
+
s, CH
CDCl
3
), 1.64 (s, CH
3
H, 3.02; N, 1.05. MS (FAB+, CH
(M - PPh , 80), 995 (M - PPh - CO, 30), 705 (M - 2CO
-
2
Cl
2
, m/z): 1287 (M , 50), 1023
+
+
+
3
3
3
Hz) (cis isomer); 36.4 (dd, J Rh-P ) 169 Hz, J P-P ) 9 Hz), 34.7
2
dd, J Rh-P ) 165 Hz, J P-P ) 9 Hz) (trans isomer). IR (CH Cl ,
1
2PPh
3
, 50). H NMR (CDCl
3
, 293 K): 9.10 (d, J H-H ) 7.1
(
2
Hz), 8.70 (d, J H-H ) 7.3 Hz), 8.20 (d, J H-H ) 7.3 Hz) (quinol),
-
1
cm ): ν(CO), 1954 (vs); ν(CO, acac), 1580 (s), 1526 (s).
Cp (a ca c)Ti(µ -S) {Ir (CO)(P P h )} ] (14) was obtained by
reaction of [Cp(acac)Ti(µ -S) {Ir(CO) ] (10) (0.063 g, 0.081
mmol) with PPh (0.043 g, 0.163 mmol) in dichloromethane
10 mL). Workup as above (method A) gave the complex as a
black solid. Yield: 0.080 g (79%). Anal. Calcd for C48
Ir Ti (%): C, 46.45; H, 3.41. Found: C, 46.39; H, 3.39.
MS (FAB+, CH
8
.00-7.00 (m, PPh
3
1
+ quinol), 6.34, 6.35, 6.31, 6.24 (s, Cp)
, 293 K): 21.7 (d, J P-P )
[
3
2
3
2
31
(four isomers). P{ H} NMR (CDCl
3
3
2
2 2
}
6
2
Hz), 21.6 (d, J P-P ) 6 Hz) (trans isomer), 20.5, 20.4, 20.1,
0.0 (s, cis isomers), 17.9 (d, J P-P ) 8 Hz), 17.5 (d, J P-P ) 8
3
(
1
-1
Hz) (trans isomer). IR (CH
2
Cl
2
, cm- ): ν(CO), 1998 cm (s).
42
H -
Deter m in a tion of Cr ysta l Str u ctu r es of [Cp (a ca c)Ti-
-S) {Rh (cod )} ] (1) a n d [Cp Ti(a ca c)][Ir (µ -S) (CO)
2
4 2 2
O P S
+
+
Cl
, 293 K): 7.70-7.13 (m, PPh
.32 (s, Cp) 5.60 (s, CH), 2.05 (s, CH ), 1.91 (s, CH
3
2
, m/z): 1240 (M , 80), 973 (M - PPh
), 6.33 (s, Cp),
), 1.51 (s,
, 293 K): 20.4
3
, 72).
(µ
3
2
2
2
3
3
2
6
]
2
1
H NMR (CDCl
3
3
(8). Single crystals for the X-ray diffraction studies were
obtained by slow diffusion of n-hexane into concentrated
solutions of the complexes in toluene at low temperature (3)
or in dichloromethane (8). A summary of crystal data, intensity
collection, and refinement parameters is reported in Table 3.
The violet (1) or dark red (8) crystals used for the X-ray
analysis were glued to a glass fiber, mounted on a Siemens-
P4 diffractometer, and irradiated with graphite-monochro-
mated Mo KR radiation (λ ) 0.71073 Å). Cell constants were
obtained from the least-squares fit on the setting angles of 25
reflections (20° e 2θ e 40°) (1) or 44 reflections (20° e 2θ e
6
3
3
1
1
CH
3
) (acac) (two isomers). P{ H} NMR (CDCl
3
(
7
s), 20.3 (s) (cis isomers), 19.4 (d, J P-P ) 7 Hz), 17.7 (d, J P-P
)
1
Hz) (trans isomer). IR (CH
2
Cl
2
, cm- ): ν(CO), 1952 (vs), 1934
(
vs); ν(CO, acac), 1578 (s), 1528 (s).
Cp (qu in ol)Ti(µ -S) {Rh (CO)(P P h
Ti(µ -S) {Rh(CO)} ] (11) (0.080 g, 0.125 mmol) was reacted
with PPh (0.066 g, 0.250 mmol) in dichloromethane (10 mL)
[
3
2
3 2
)} ] (15). [Cp(quinol)-
3
2
2
3
to give a garnet solution and evolution of carbon monoxide.
The solution was stirred for 30 min and the solvent removed
under vacuum to give a violet microcrystalline residue, which
was washed with cold hexane and dried under vacuum.
3
5.6°) (8). A complete set of independent reflections with 2θ
up to 50° (-20 e h e 0, -13 e k e 1, and -15 e l e 0 for 1,
and -11 e h e 1, -17 e k e 1, and -22 e l e 22 for 8) was
measured at 173(2) K for each crystal, using the ω/2θ scan
technique. Three standard reflections were monitored every
100 measurements throughout data collection as a check on
crystal and instrument stability; no decay was observed. Both
data were corrected for Lorentz and polarization effects.
3 2 2 2
Yield: 0.115 g (83%). Anal. Calcd for C52H41NO P Rh S Ti
(
1
3
%): C, 56.38; H, 3.73; N, 1.26. Found: C, 56.15; H, 3.40; N,
+
.31. MS (FAB+, CH
2
Cl
2
, m/z): 1108 (M , 10), 1079 (M - CO,
+
+
5), 1051 (M - 2CO, 8), 789 (M - 2CO - PPh
3
, 100), 526
, 293 K): 9.20 (d,
H-H ) 7.2 Hz), 8.22 (d, J H-H ) 7.3 Hz), 7.81-6.71 (m, PPh
+
1
(
J
M
3 3
- 2CO - 2PPh , 50). H NMR (CDCl
3
+
3
1
1
quinol), 6.28, 6.21, 6.14 (s, Cp) (four isomers). P{ H} NMR

5
310 Organometallics, Vol. 18, No. 25, 1999
Casado et al.
3
Reflections were also corrected for absorption using an empiri-
cal method (Ψ-scan).41
residual electron density peaks, weaker than 1.00 e/Å in both
structures, were situated in close proximity to the metal atoms
and have no chemical sense. Scattering factors were used as
Both structures were solved by Patterson and subsequent
4
2
43
difference Fourier techniques (SHELXTL-PLUS) and refined
implemented in the refinement program.
2
43
by full-matrix least-squares on F (SHELXL-97). Anisotropic
displacement parameters were included for all non-hydrogen
atoms. Hydrogen atoms were included in the last cycles of
refinement, most of them from observed (1) or calculated
Ack n ow led gm en t. We wish to thank Direcci o´ n
General de Ense n˜ anza Superior (DGES) for financial
support (Projects PB95-221-C1 and PB94-1186), the EU
Human Capital and Mobility Programme, and Diputa-
ci o´ n General de Arag o´ n for fellowships (to A.J .E. and
M.A.C., respectively).
positions (8). All were refined with positional and displacement
2
riding parameters. The function minimized was ∑[w(F
o
-
2
2
2
2) + (aP)2
,0) + 2F )]/3; all the refinements
c
converged to reasonable R factors (see Table 3). The highest
F
c
) ]. The calculated weighting scheme was 1/[σ (F
o
2
2
+
bP], where P ) [max(F
o
Su p p or tin g In for m a tion Ava ila ble: An X-ray crystal-
lographic file, also in CIF format, for complexes 1 and 8 is
available. This material is available free of charge via the
Internet at http://pubs.acs.org.
(
41) XPREP Program (SHELXTL v 5.0); Siemens Analytical X-ray
Instruments, Inc.: Madison, WI, 1994.
42) Sheldrick, G. M. SHELXTL-PLUS; Siemens Analytical X-ray
Instruments: Madison, WI, 1990.
43) Sheldrick, G. M. SHELXL-97 Program for Crystal Structure
Refinement; University of G o¨ ttingen: G o¨ ttingen, Germany, 1997.
(
(
OM990623P