Chemistry of metal-metal-bonded early-late heterobimetallics: Cooperative reactions of functional groups at a persistent organometallic Zr-Rh framework

Article abstract of DOI:10.1021/om049346z

The reaction of (C₅H₄-PPh₂) ₂Zr(CH₃)₂ (5a) with HRh(COXPPh ₃)₃ (6) leads to methane evolution and the formation of the early-late heterobimetallic complex [(μ-C₅H ₄-PPh₂)₂-(H₂C-Zr-Rh(CO)PPh ₃)] (7a), which was characterized by X-ray diffraction (d(Zr-Rh) = 2.863(1) A). The analogous dialkylphosphino-substituted complexes (C ₅H₄-PR₂)₂Zr(CH₂) ₂ (5b, R = isopropyl; 5c, R = cyclohexyl) react with the hydrido-rhodium reagent 6 to initially form the analogous bimetallic (Zr-Rh) complexes 7b,c, respectively. However, these complexes are not stable at ambient temperature in toluene solution, due to an equilibration with the products [(μ-C₅H₄-PR₂)₂(μ-CH ₃-Zr-Rh(PPh₃))] (11) and [(μ-C₅H ₄-PR₂)₂(H₃C-Zr-Rh-(CO)₂)] (10). Treatment of the initially formed complexes 7b,c with carbon monoxide rapidly leads to the formation of the H₃C(Zr-Rh)-dicarbonyl complexes 10b,c. The product 10bc was characterized by X-ray crystal structure analysis. The systems 7b,c are not stable in dichloromethane. They react readily with the solvent by abstraction of two chlorine atoms to yield the compounds [(μ-C₅H₄-PR₂)₂(μ-0=C(CH ₃))(Cl-Zr-Rh-Cl)] (12b,c). Both products were characterized by X-ray diffraction. A cooperative action of the involved metals is assumed to account for the observed reactions at the intact heterobimetallic Zr-Rh framework.

Full text of DOI:10.1021/om049346z

214
Organometallics 2005, 24, 214-225
Chemistry of Metal-Metal-Bonded Early-Late
Heterobimetallics: Cooperative Reactions of Functional
Groups at a Persistent Organometallic Zr-Rh
Framework
Carsten Cornelissen, Gerhard Erker,* Gerald Kehr, and Roland Fro¨hlich
Organisch-Chemisches Institut der Universita¨t Mu¨nster, Corrensstrasse 40,
D-48149 Mu¨nster, Germany
Received August 20, 2004
The reaction of (C5H4-PPh2)2Zr(CH3)2 (5a) with HRh(CO)(PPh3)3 (6) leads to methane
evolution and the formation of the early-late heterobimetallic complex [(µ-C5H4-PPh2)2-
(H3C-Zr-Rh(CO)PPh3)] (7a), which was characterized by X-ray diffraction (d(Zr-Rh) )
2.863(1) Å). The analogous dialkylphosphino-substituted complexes (C5H4-PR2)2Zr(CH3)2
(5b, R ) isopropyl; 5c, R ) cyclohexyl) react with the hydrido-rhodium reagent 6 to initially
form the analogous bimetallic (Zr-Rh) complexes 7b,c, respectively. However, these complex-
es are not stable at ambient temperature in toluene solution, due to an equilibration with
the products [(µ-C5H4-PR2)2(µ-CH3-Zr-Rh(PPh3))] (11) and [(µ-C5H4-PR2)2(H3C-Zr-Rh-
(CO)2)] (10). Treatment of the initially formed complexes 7b,c with carbon monoxide rapidly
leads to the formation of the H3C(Zr-Rh)-dicarbonyl complexes 10b,c. The product 10c
was characterized by X-ray crystal structure analysis. The systems 7b,c are not stable in
dichloromethane. They react readily with the solvent by abstraction of two chlorine atoms
to yield the compounds [(µ-C5H4-PR2)2(µ-OdC(CH3))(Cl-Zr-Rh-Cl)] (12b,c). Both products
were characterized by X-ray diffraction. A cooperative action of the involved metals is
assumed to account for the observed reactions at the intact heterobimetallic Zr-Rh
framework.
Chart 1
Introduction
Early-late heterobimetallic (ELHB) complexes may
offer unique pathways of transforming organic sub-
strates, since they have the potential to open cooperative
reaction channels in which both transition-metal centers
may participate in the activation of reagents and/or
stabilization of transition states or products.1 In the
past, ELHB complexes of a great structural variety were
prepared and tested: e.g., as models for otherwise
heterogeneously catalyzed reactions.2,3 The group 4
metals have participated significantly in this develop-
ment.4-10 However, surprisingly few Zr/Rh complexes
of this type have been described so far: among these,
only very few examples that contained a Zr-Rh metal-
metal bond.11-16
Scheme 1
The two most important classes of heterobimetallic
Zr/Rh systems used pendant donor ligands at the
periphery of the group 4 metal component to coordinate
to the late metal. These were either part of the σ-ligand
system11-13 (e.g. the examples in Chart 1 and Scheme
1) or they were attached to, for example, the ubiquitous
Cp ligands at zirconium (see Scheme 2).14-16 The Zr‚‚‚Rh
separation in the typical examples of the type I com-
plexes (1a,b)11 shown in Chart 1 is >3 Å; structural and
electronic features make the presence of a metal-metal
bond in these systems unlikely. In contrast, the reaction
of Cp*ZrMe(OCH2PPh2)2 (2) with RRh(PPh3)3 (3a, R )
* To whom correspondence should be addressed. E-mail: erker@
uni-muenster.de.
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10.1021/om049346z CCC: $30.25 © 2005 American Chemical Society
Publication on Web 12/16/2004

Metal-Metal-Bonded Early-Late Heterobimetallics
Organometallics, Vol. 24, No. 2, 2005 215
Scheme 2
Scheme 3
Me; 3b, R ) H) led to the metal-metal-bonded com-
plexes 4a,b, respectively, as shown by Wolczanski et al.
(see Scheme 1).13 Complex 4a features a Zr-Rh bond
length of 2.444(1) Å in the crystal state, which is far
below the sum of the covalent radii (2.70 Å) or metal
atom radii (2.94 Å) of these metals.
We had recently described the reaction of the complex
(C5H4-PPh2)2Zr(CH3)2 (5) with HRh(CO)(PPh3)3 (6) to
yield the heterobimetallic product 7.16 Complex 7 was
characterized spectroscopically. It was thought to con-
tain a Zr-Rh metal-metal bond. Complex 7 is a very
active (but not very selective) hydroformylation catalyst.
We have now been able to characterize this very
sensitive complex by X-ray diffraction, and we have
prepared several related examples of this general
structural type by using dialkylphosphino donor groups
attached at the Cp ligands. These systems underwent
some surprising reactions involving the σ ligands at both
metal centers along the persistent Zr-Rh framework.
These reactions and the structures of the resulting novel
early-late heterobimetallic complexes will be described
in this article.
of phosphino-substituted cyclopentadienides using a
method analogous to that described by Casey et al. for
the preparation of the reagent 8a.17 Lithium or sodium
cyclopentadienide was treated with the respective dia-
ryl- or dialkylchlorophosphine ClPR2 (R ) Ph, isopropyl,
cyclohexyl, tert-butyl) in toluene. The in situ formed
mixture of the R2P-substituted cyclopentadiene products
were not isolated but directly deprotonated by subse-
quent treatment with n-butyllithium to give the corre-
sponding [C5H4-PR2]Li reagents (8a-d). The diisopro-
pyl- and cyclohexyl-substituted reagents were isolated
in excellent yields (8b, 86%; 8c, 99%); only the bulky
di-tert-butylphosphino-CpLi analogue (8d) was ob-
tained in rather poor yield (24%), even after several
attempts (see Scheme 3).
Results and Discussion
Synthesis and Characterization of the (C5H4-
PR2)2ZrX2 Complexes. We chose to prepare a series
Transmetalation of the reagents 8a-d with zirconium
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216 Organometallics, Vol. 24, No. 2, 2005
Cornelissen et al.
Table 1. Comparison of 31P NMR Chemical Shifts
of the [C5H4-PR2]nM Compounds 8, 9, and 5
R
compd
M
n
C6H5 (a) i-C3H7 (b) C6H11 (c) t-C4H9 (d)
8
9
5
Li
1
2
2
-18.8
-17.3
-18.9
3.1
5.1
2.3
-11.8
-3.0
-6.1
25.3
34.4
31.7
ZrCl2
ZrMe2
described by Tikkanen et al. for the synthesis of 9a.18,19
The reaction in toluene solution that contained ca. 0.4%
of THF cleanly gave the corresponding phosphino-
substituted zirconocene dichloride complexes 9a-d
(isolated in yields around ca. 70%). Subsequent treat-
ment with 2 molar equiv of methyllithium eventually
converted them into the dimethylzirconocene complexes
5a-d (see Scheme 3).
The compounds 5, 8, and 9a-d were characterized
spectroscopically (for a compilation of their typical 31P
NMR shifts see Table 1). In solution they feature the
typical 1H and 13C NMR spectra of conformationally
rapidly equilibrating, open bent-metallocene systems
(e.g. 9b; 1H NMR δ 6.68, 6.53 (C5H4), δ 2.05 (sept), 1.15
(dd, 2JPH ) 13.7 Hz, 3JHH ) 7.1 Hz), and 0.99 (dd, 2JPH
) 12.7 Hz, 3JHH ) 7.1 Hz, isopropyl)). The corresponding
diisopropylphosphino-substituted dimethylzirconocene
Figure 1. View of the molecular structure of complex 9a,
showing the bis-lateral:anti metallocene conformation.
Selected bond lengths (Å) and angles (deg): Zr-Cl1 )
2.414(1), Zr-Cl2 ) 2.423(1), P1-C1 ) 1.839(4), P1-C11
) 1.849(5), P1-C21 ) 1.839(5), P2-C6 ) 1.831(4), P2-
C31 ) 1.834(4), P2-C41 ) 1.856(4); Cl1-Zr-Cl2 ) 96.10(5),
C1-P1-C11 ) 100.5(2), C1-P1-C21 ) 100.4(2), C11-
P1-C21 ) 101.7(2), C6-P2-C31 ) 99.8(2), C6-P2-C41
) 100.5(2), C31-P2-C41 ) 101.7(2).
diffraction. The structural features of complex 5a had
previously been described by us.16 All these systems
show the typical structural properties of open, non-
bridged group 4 bent-metallocene frameworks. However,
they seem to belong to two slightly different conforma-
tional metallocene types in the crystal.20 The diphe-
nylphosphino-C5H4 system 9a features a very typical
conformational arrangement that has both C(Cp)-P
vectors almost ideally pointing toward the opposite
lateral sectors at the bent-metallocene framework (bis-
lateral:anti orientation, see Figure 1). The bulky -PPh2
substituents thus are placed at a maximal distance from
each other (d(P1‚‚‚P2) ) 7.58 Å; see Table 2). Both
phenyl groups at the phosphorus atoms of complex 9a
are oriented toward the backside of the bent-metallocene
wedge; their lone pairs are directed toward the front
side. The related (C5H4-PPh2)2Zr(CH3)2 complex 5a
shows a very similar conformational arrangement in the
crystal.
All the (dialkylphosphino-Cp)2ZrX2 complexes inves-
tigated in the course of this study show a metallocene
conformation that features the bulky -PR2 substituents
oriented substantially closer to the narrow backside of
the bent-metallocene wedge. A typical example is com-
plex 9b (R ) isopropyl). The conformational type (bis-
lateral:gauche) shows a torsional angle between the Cp
ligand vectors of only ca. -102.6°, which brings the
phosphorus atoms much closer together (5.26 Å) than
in 9a (see above). All the other (dialkylphosphino-
C5H4)2ZrX2 complexes (9c,d and 5b,c) show analogous
structural features (Figure 2 and Table 2; for details
see the Supporting Information).
complex (5b) also shows a pair of diastereotopic isopro-
2
pyl CH3 NMR resonances (13C NMR δ 20.2 (d, JPC
)
2
3.0 Hz) and 20.1 (d, JPC ) 6.0 Hz)) in addition to the
Zr-CH3 signals at δ -0.32 (1H, s, 6H) and δ 32.2 (13C,
t, JPC ) 3.4 Hz).
The zirconocene dichloride complexes 9a-d and the
dimethylzirconocenes 5b,c were characterized by X-ray
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N.; Moreno, M. T. J. Organomet. Chem. 1995, 494, 261-265. Le
Gendre, P.; Maubrou, E.; Blaque, O.; Boni, G.; Mo¨ıse, C. Eur. J. Inorg.
Chem. 2001, 1437-1440. Antin˜olo, A.; Ferna´ndez-Gala´n, R.; Orive, I.;
Otero, A.; Prashar, S. Eur. J. Inorg. Chem. 2002, 2470-2476. Le
Gendre, P.; Comte, V.; Micholot, A. Mo¨ıse, C. Inorg. Chim. Acta 2003,
350, 289-292.
Zr-Rh Heterobimetallic Systems. The reactive
organometallic bis(diphenylphosphino-Cp)ZrMe2 chelate
(20) Kru¨ger, C.; Nolte, M.; Erker, G.; Thiele, S. Z. Naturforsch. 1992,
47b, 995-999. Erker, G.; Aulbach, M.; Knickmeyer, M.; Wingbermu¨hle,
D.; Kru¨ger, C.; Nolte, M.; Werner, S. J. Am. Chem. Soc. 1993, 115,
4590-4601. Fritze, C.; Knickmeier, M.; Erker, G.; Zaegel, F.; Gauth-
eron, B.; Meunier, P. Organometallics 1995, 14, 5446-5449. Knick-
meier, M.; Erker, G.; Fox, T. J. Am. Chem. Soc. 1996, 118, 9623-9630.

Metal-Metal-Bonded Early-Late Heterobimetallics
Table 2. Selected Structural Parameters of the [C5H4-PR2]2ZrX2 Complexes 5 and 9
5a16
9a 5b 9b 5c 9c
Organometallics, Vol. 24, No. 2, 2005 217
compd
9d
R
X
Ph
Ph
Cl
96.10(5)
127.7
-170.8
7.58
i-Pr
i-Pr
Cy
Cy
Cl
94.20(3)
130.1
-103.3
5.13
t-Bu
CH3
CH3
Cl
CH3
Cl
X-Zr-X, deg
Cp-Zr-Cp, deg
θ,a deg
92.9(2)
130.2
92.3(3)
133.9
96.8
95.34(3)
130.5
-102.6
5.26
93.0(1)
135.0
-91.9
4.98
93.66(2)
132.4
93.2
P1‚‚‚P2, Å
7.59
5.10
4.89
a Torsional angle between the substituent vectors, expressed as C(Cp)-Cp(centroid)-Cp(centroid)-C(Cp).
Figure 2. Molecular structure of complex 9b. Selected
bond lengths (Å) and angles (deg): Zr-Cl1 ) 2.4439(6),
P1-C1 ) 1.834(2), P1-C11 ) 1.859(2), P1-C14 ) 1.868(2);
Figure 3. View of the molecular structure of the hetero-
bimetallic Zr-Rh complex 7a. Selected bond lengths (Å)
and angle (deg) (values for the second molecule in brack-
ets): Zr1-C1 ) 2.290(7) [2.278(6)], Zr1-Rh1 ) 2.865(1)
[2.860(1)], Rh1-C91 ) 1.877(7) [1.876(7)], Rh1-P11 )
2.306(2) [2.302(2)], Rh1-P21 ) 2.319(2) [2.318(2)], Rh1-
P31 ) 2.386(2) [2.389(2)], C91-O91 ) 1.146(7) [1.156(7)];
C1-Zr1-Rh1 ) 107.1(2) [107.3(2)], Zr1-Rh1-P11 ) 77.2(1)
[76.7(1)], Zr1-Rh1-P21 ) 79.0(1) [78.9(1)], Zr1-Rh1-P31
) 175.3(1) [173.4(1)], Zr1-Rh1-C91 ) 80.9(2) [80.1(2)],
P11-Rh1-P21 ) 119.0(1) [119.8(1)], P11-Rh1-P31 )
102.2(1) [104.6(1)], P11-Rh1-C91 ) 114.4(2) [111.3(2)],
P21-Rh1-P31 ) 105.3(1) [105.7(1)], P21-Rh1-C91 )
115.8(2) [117.4(2)], P31-Rh1-C91 ) 95.3(2) [93.4(2)],
Rh1-C91-O91 ) 173.5(6) [175.9(6)]; C1-Zr1-Rh1-C91
) 15.6(3) [22.8(3)].
Cl1-Zr-Cl1* ) 95.34(3), C1-P1-C11 ) 101.89(8), C1-
P1-C14 ) 99.49(8), C11-P1-C14 ) 102.79(9).
ligand21 was treated with HRh(CO)(PPh3)3 (6) as previ-
ously described by us16 to yield the Zr-Rh-bonded
heterobimetallic product 7a. It was extremely difficult
to separate the organometallic products from such
reactions from the liberated triphenylphosphine. This
was due to their similar solubilities, but in addition it
turned out that the products 7 were rather unstable in
the complete absence of PPh3. The observed unusual
chemical features of the corresponding -P(isopropyl)2-
and -P(cyclohexyl)2-substituted products (7b,c; see
below) may offer some explanation for this unexpected
behavior. Complex 7a can best be obtained free of PPh3
by Soxhlet extraction of the solid for 2 days with pentane
under strictly anhydrous conditions. Complex 7a had
previously only been characterized spectroscopically. By
slow evaporation of the solvent from a toluene solution,
we were now able to obtain single crystals of 7a that
allowed an X-ray crystal structure analysis of this
example of the novel Zr-Rh-bonded early-late hetero-
bimetallic complex type.
In the crystal two independent molecules of complex
7a were found (Figure 3). They are chemically equiva-
lent. Values of the second molecule will be given in
brackets. In 7a the zirconium center is pseudotetrahe-
drally coordinated to a pair of η5-bonded C5H4-[P]
ligands (the Zr-C(Cp) bond lengths are within a small
range between 2.435(8) and 2.567(6) Å [2.461(6)-2.570-
(6) Å]), a σ-methyl group (Zr-C1 ) 2.290(7) Å [2.278(6)
Å]), and the rhodium center. The Zr-Rh distance
amounts to 2.865(1) Å [2.860(1) Å]. This is between the
values of the sum of the Zr/Rh covalent radii (2.70 Å)
and the sum of the metal atom radii (2.91 Å), and this
probably indicates the presence of a strong Zr-Rh
metal-metal bond in these types of complexes. To our
knowledge, the metal-metal distance in 7a represents
the second shortest Zr-Rh bonding interaction observed
so far.
The Rh1-Zr1-CH3 angle in 7a amounts to the typical
107.1(2)° [107.3(2)°]. The Rh center in complex 7a shows
a distorted-trigonal-bipyramidal coordination geometry.
In this arrangement the chelate (Cp)-PPh2 donor
ligands and the single CO group occupy the three
equatorial positions (bond lengths Rh1-C91 ) 1.877(7)
Å [1.876(7) Å] and C91-O92 ) 1.146(7) Å [1.156(7) Å]
(angle Rh1-C91-O92 ) 173.5(6)° [175.9(6)°]), Rh1-P11
) 2.306(2) Å [2.302(2) Å], and Rh1-P21 ) 2.319(2) Å
[2.318(2) Å]; bond angles P11-Rh1-P21 ) 119.0(1)°
[119.8(1)°], P11-Rh1-C91 ) 114.4(2)° [111.3(2)°], and
P21-Rh1-C91 ) 115.8(2)° [117.4(2)°]). The axial posi-
tions are occupied by the remaining PPh3 ligand (Rh-
P31 ) 2.386(2) Å [2.389(2) Å]; this Rh-P bond is slightly
longer than the adjacent ones) and the Zr center (angle
Zr1-Rh1-P31 ) 175.3(1)° [173.4(1)°]). All three angles
between Ph3P and the cis ligands are slightly larger
(21) Tikkanen, W.; Ziller, J. P. Organometallics 1991, 10, 2266-
2273.

218 Organometallics, Vol. 24, No. 2, 2005
Cornelissen et al.
54.6; 1H NMR, δ 6.23, 6.02, 4.80, 3.77 (C5H4), 1.48, 1.40,
1.14, 1.00 (diastereotopic CH3 of the two pairs of
isopropyl groups at P)).
Scheme 4
The stoichiometric coproduct 11b was formed from
7b by dissociation of the carbon monoxide ligand. The
complex also features the typical NMR signals of the
rigid [C5H4-P(i-Pr)2]2Zr-Rh framework (1H, δ 6.00,
5.91, 5.50, 4.75 (C5H4), 1.41, 1.38, 1.13, 0.93 (i-PrCH3))
characterized by the typical cis/trans differentiation of
the pairs of C5H4- and isopropyl resonances. The 31P
NMR signal of the remaining PPh3 ligand at Rh occurs
2
at δ 33.4 (dt) with a JPP coupling constant of 25.1 Hz
that is typically observed at the intact heterobimetallic
metal-metal-bonded Zr-Rh framework (1JRhP ) 166.3
Hz). The -P(i-Pr)2 31P NMR resonance of complex 11b
than the ideal 90° (P31-Rh1-P11 ) 102.2(1)° [104.6(1)°],
P31-Rh1-P21 ) 105.3(1)° [105.7(1)°], and P31-Rh1-
C91 ) 95.3(2)° [93.4(2)°]). The three equatorial ligands
are leaning slightly over to zirconium (P11-Rh1-Zr1
) 77.2(1)° [76.7(1)°] and P21-Rh1-Zr1 ) 79.0(1)°
[78.9(1)°]). This effect is not only observed inside the
chelate framework but also includes the CtO ligand,
although here this structural effect is slightly less
pronounced (C91-Rh1-Zr1 ) 80.9(2)° [80.1(2)°]).
The bis(diisopropylphosphino-cyclopentadienyl)zir-
conium dimethyl reagent (5b) initially reacts in a
similar way with the hydridocarbonylrhodium(I) com-
plex 6. We observed methane evolution22 with formation
of the heterobimetallic complex 7b (see Scheme 4).
Complex 7b features two 31P NMR resonances in
toluene-d8 at 273 K in a 2:1 intensity ratio: the signal
of the single remaining PPh3 ligand occurs at δ 47.8 as
1
occurs at δ 33.2 (243 K, d8-toluene, dd, JRhP ) 195.9
2
Hz, JPP ) 25.1 Hz). The remaining methyl group at
1
zirconium gives rise to H/13C NMR signals at δ -0.26
3
(d, JPH ) 3.8 Hz)/δ 14.2 (at 243 K).
The observed small coupling with the PPh3 ligand at
Rh causes us to believe that this methyl group is
bridging between the early and the late metal inside
the very rigid framework of complex 11b.
The [C5H4-P(cyclohexyl)2)]2ZrMe2 (5c) system reacts
similarly with [HRh(CO)(PPh3)3] (6). At -30 °C in
toluene solution it rapidly forms the primary product
7c with evolution of methane. Compound 7c shows the
typical NMR features of this dimetallic Zr-Rh complex
type (1H, δ 6.86, 6.21, 4.71, 4.17 (C5H4), -0.26 (Zr-CH3);
31P, δ 51.0 (dt, 1JRhP ) 116.1 Hz, 2JPP ) 32.6 Hz, PPh3),
23.1 (dd, 1JRhP ) 152.8 Hz, 2JPP ) 32.6 Hz, -PCy2); 13C,
δ 193.2 (CO), 29.1 (1JCH ) 118.3 Hz, Zr-CH3 at 243 K).
Again, complex 7c is not very stable at room temper-
ature. During ca. 12 h at ambient temperature it reacted
further to give a mixture of the products 10c and 11c.
In this case the dimetallic Zr-Rh dicarbonyl complex
10c showed only a low solubility in toluene and pre-
cipitated from the solution as dark red crystals. Again,
the Zr-Rh dicarbonyl 10c could be prepared alterna-
tively by treatment of 7c with carbon monoxide. Forma-
tion of 10c occurred instantaneously, and the product
was isolated in close to quantitative yield. It features
the typical NMR spectra of this type of complexes (10c
in d5-bromobenzene; 1H, δ 6.44, 6.24, 5.15, 4.20 (C5H4),
-0.76 (Zr-CH3); 13C, δ 28.9 (1JCH ) 117.0 Hz, Zr-CH3)),
and it was characterized by X-ray diffraction (see below).
a doublet of triplets with coupling constants of 1JRhP
)
112.1 Hz and 2JPP ) 34.4 Hz, and the signal of the pair
of symmetry-equivalent -P(i-Pr)2 units is observed at
1
2
1
δ 33.7 (dd, JRhP ) 154.5 Hz, JPP ) 34.4 Hz). The H
NMR spectrum of 7b shows four C5H4 signals (δ 6.64,
6.10, 4.82, 4.17), and it features the resonances of the
four diastereotopic isopropyl methyl groups (δ 1.23, 1.18,
1.10, 0.90). The 1H NMR signal of the Zr-CH3 σ-ligand
of 7b appears at δ -0.46 (13C δ 29.0), and the CO 13C
NMR resonance was located at δ 194.5. Complex 7b
exhibits a ν(CO) IR band at 1879 cm-1
.
Complex 7b is not stable at room temperature for a
prolonged time. At room temperature it reacts within
days to give two new compounds (10b and 11b). After
1 week ca. 20% of 7b reacted to give these new
compounds. Increasing the temperature to 373 K results
in the rapid formation of an equilibrium mixture of ca.
7% of 7b and 93% of the 10b/11b mixture. Cooling shifts
the equilibrium ratio back toward the starting material
(7b:10b/11b ) 19:81 (353 K), 40:60 (313 K), 65:35 (283
K)).
Complex 11c also features the typical NMR reso-
nances of the rigid [(C5H4-PR2)2]Zr-Rh(PPh3) frame-
work (31P, δ 34.5 (dt, 1JRhP ) 164.4 Hz, 2JPP ) 25.2 Hz,
1
2
1
PPh3), 26.3 (dd, JRhP ) 196.1 Hz, JPP ) 25.2 Hz); H,
δ 6.09, 5.94, 5.61, 4.84 (C5H4)). The 1H/13C NMR
resonances of the [Zr]-CH3 σ-ligand of 11c occur at δ
-0.29 (d, 3JPH ) 3.4 Hz)/δ 14.4 (1JCH ) 120.7 Hz). Again,
the observed coupling with the PPh3 phosphorus and
the marked high-field shift of the 13C NMR resonance
may indicate bridging of the methyl group across the
Zr-Rh bond in complex 11c.
The product 10b was obtained independently as a
single product by bubbling CO gas through a toluene
solution of 7b at -30 °C. Complex 10b contains two CO
ligands at rhodium (ν 1959 and 1913 cm-1 13C NMR δ
;
213.3 and 191.5). It features a σ-CH3 ligand at zirconium
(1H NMR, δ -0.83; 13C NMR, δ 28.9). The H3CZr-Rh-
(CO)2 subunit is held together by the typical rigid
framework made up of the pair of Cp-P(i-Pr)2 ligands
located above and below the σ skeleton (31P NMR, δ
Complex 10c was characterized by X-ray diffraction
(see Figure 4). Its general framework is very similar to
that of complex 7a. Complex 10c features a strong Zr-
Rh interaction (2.893(1) Å) between the pseudo-trigonal
bipyramidally coordinated Rh and the pseudotetrahe-
dral Zr centers. The apical Rh-CO linkage (Rh-C3 )
1.911(4) Å, C3-O3 ) 1.147(5) Å, angle Rh-C3-O3 )
(22) Renaut, P:; Tainturier, G.; Gautheron, B. J. Organomet. Chem.
1978, 150, C9-C10. Norton, J. R. Acc. Chem. Res. 1979, 12, 139-145.

Metal-Metal-Bonded Early-Late Heterobimetallics
Organometallics, Vol. 24, No. 2, 2005 219
Figure 5. View of the molecular structure of the µ-acetyl
Zr-Rh complex 12b. Selected bond lengths (Å) and angles
(deg): Zr-Cl1 ) 2.552(1), Zr-O1 ) 2.216(2), Zr-Rh )
2.966(1), Rh-Cl2 ) 2.436(1), Rh1-C1 ) 1.916(2), Rh-P1
) 2.308(1), Rh-P2 ) 2.322(1), O1-C1 ) 1.271(3), C1-C2
) 1.511(3); Cl1-Zr-Rh ) 138.92(2), O1-Zr-Rh ) 63.99(4),
Cl1-Zr1-O1 ) 75.04(4), Zr-Rh-P1 ) 81.72(2), Zr-Rh-
P2 ) 82.21(2), Zr-Rh-C1 ) 67.13(6), Zr-Rh-Cl2 )
119.73(2), P1-Rh-P2 ) 162.29(2), P1-Rh-C1 ) 90.37-
(6), P1-Rh1-Cl2 ) 91.64(2), P2-Rh-C1 ) 90.22(6), P2-
Rh-Cl2 ) 89.89(2), C1-Rh-Cl2 ) 173.07(6), Zr1-O1-
C1 ) 105.7(1), O1-C1-C2 ) 114.6(2), O1-C1-Rh )
123.0(2), C2-C1-Rh ) 122.4(2).
Figure 4. Projection of the molecular geometry of the
heterobimetallic Zr-Rh complex 10c. Selected bond lengths
(Å) and angles (deg): Zr-C1 ) 2.312(4), Zr-Rh ) 2.893(1),
Rh-C2 ) 1.869(4), Rh-C3 ) 1.911(4), Rh-P1 ) 2.337(1),
Rh-P2 ) 2.328(1), C2-O2 ) 1.155(5), C3-O3 ) 1.147(5);
C1-Zr-Rh ) 108.1(1), Zr-Rh-P1 ) 78.95(3), Zr-Rh-P2
)
78.37(3), Zr-Rh-C2 ) 77.15(12), Zr-Rh-C3 )
175.05(13), P1-Rh-P2 ) 123.97(4), P1-Rh-C2 ) 114.60-
(13), P1-Rh-C3 ) 98.36(13), P2-Rh-C2 ) 109.09(13),
P2-Rh-C3 ) 99.98(13), C2-Rh-C3 ) 107.8(2), Rh-C2-
O2 ) 170.8(4), Rh-C3-O3 ) 179.3(4); C1-Zr-Rh-C2 )
-4.4(2), C1-Zr-Rh-C3 ) 171.7(2).
Scheme 5
179.3(4)°) is slightly longer than the equatorial Rh-CO
bond (Rh-C2 ) 1.869(4) Å). The Rh-P1 (2.337(1) Å)
and Rh-P2 (2.328(1) Å) vectors are slightly leaning over
to Zr (angles Zr-Rh-P1 ) 78.95(3)°, Zr-Rh-P2 )
78.37(3)°, and Zr-Rh-C2 ) 77.15(12)°) inside the
distorted-trigonal-bipyramidal coordination geometry at
Rh (angles P1-Rh-P2 ) 123.97(4)°, P1-Rh-C2 )
114.60(13)°, P2-Rh-C2 ) 109.09(13)°). The Zr-Rh-
C3 angle between the Zr-Rh and the trans-Rh-CO
vectors amounts to 175.05(13)°, and the angle between
the cis-CO ligands at rhodium was found at 107.8(2)°
(C2-Rh-C3). The methyl group at the adjacent zirco-
nium center features a typical Zr-C(sp3) σ-bond dis-
tance (Zr-C1 ) 2.312(4) Å, angle C1-Zr-Rh )
108.1(1)°), and the C5H4-[P] rings are rather uniformly
η5-coordinated to the early-metal center (Zr-C(Cp)
ranging from 2.465(4) to 2.551(4) Å).
The complexes 7b,c are not stable in chlorinated
hydrocarbon solvents. When the reaction between, for
example, 5b with [HRh(CO)(PPh3)3] (6) was carried out
in dichloromethane or when the heterobimetallic prod-
uct 7b was dissolved in dichloromethane solvent at
ambient temperature, a practically quantitative conver-
sion to a single new product (12b) was observed. The
same product (12b) was obtained when the heterobi-
metallic Zr-Rh dicarbonyl complex 10b was kept in
dichloromethane at room temperature for a prolonged
time (16 h). The corresponding -P(cyclohexyl)2-substi-
tuted system (12c) was obtained by any of the three
methods starting from 5c, 7c, or 10c by analogous
reactions with dichloromethane (see Scheme 5).
(2.966(1) Å) in complex 12b (see Figure 5) is slightly
larger than in the other Zr-Rh structures that were
determined in this study, but this probably still repre-
sents a metal-metal-bonded interaction. The Zr-Rh
bond in 12b is bridged by a µ(C,O)-acetyl ligand that
was formed by an intramolecular CO insertion in a
metal-carbon bond across the Zr-Rh linkage. Since
such CO insertion reactions mechanistically are always
migratory insertions,23 our observation that the µ-Od
CMe ligand is oxygen-coordinated to zirconium and
carbon-bonded to rhodium is not unexpected. The Zr-O
bond length amounts to 2.216(2) Å.24 The CdO bond
length is 1.271(3) Å (C1-O1). The Rh-C1 bond25 is
rather short at 1.916(2) Å, which may indicate some
Rh-C multiple-bond character26 inside the planar
µ-acetyl (Zr-Rh) four-membered ring (see Scheme 6).
The Zr-O1-C1 angle is found at 105.7(1)°, and the O1-
C1-Rh angle amounts to 123.0(2)°.
(23) Erker, G. Acc. Chem. Res. 1984, 17, 103-109.
(24) Erker, G.; Mena, M.; Hoffmann, U. Menjo´n, B.; Petersen, J. L.
Organometallics 1991, 10, 291-298.
(25) Hill, A. F.; White, A. J. P.; Williams, D. J.; Wilton-Elu, J. D. E.
T. Organometallics 1998, 17, 3152-3154.
The complexes 12b,c were both characterized by
X-ray crystal structure analyses. The Zr-Rh distance

220 Organometallics, Vol. 24, No. 2, 2005
Cornelissen et al.
Scheme 6
In the µ-acetyl(Zr-Rh) complex 12b the rhodium
center features a square-pyramidal coordination envi-
ronment with the trans phosphines, a chloride (Cl2) and
the acetyl carbon atom C1 being placed in the basal
plane (Rh-P1 ) 2.308(1) Å, Rh-P2 ) 2.322(1) Å, Rh-
Cl2 ) 2.436(1) Å) and the zirconium atom in the apical
position (see Figure 5). Consequently, the interligand
angles at the base are all very close to ideal 90° (C1-
Rh-P1 ) 90.37(6)°, C1-Rh-P2 ) 90.22(6)°, Cl2-Rh-
P1 ) 91.64(2)°, Cl2-Rh-P2 ) 89.89(2)°), although all
four ligands are leaning slightly over to zirconium (C1-
Rh-Cl2 ) 173.07(6)°, P1-Rh-P2 ) 162.29(2)°). The
Zr-O1 vector is bisecting the Rh-Zr-Cl angle inside
the metallocene σ-ligand plane (Cl1-Zr-O1 ) 75.04-
(4)°, Zr-Cl1 ) 2.552(1) Å). The cyclopentadienyl ligands
at the zirconium center are rather uniformly η5 coordi-
nated, with the Zr-C(Cp) bond lengths ranging from
2.490(2) to 2.561(2) Å.
Figure 6. Molecular structure of complex 12c. Selected
bond lengths (Å) and angles (deg) (values for the second
molecule in brackets): Zr1-Cl2 ) 2.551(1) [2.553(1)], Zr1-
O1 ) 2.211(2) [2.213(2)], Zr1-Rh1 ) 2.980(1) [2.983(1)],
Rh1-Cl1 ) 2.440(1) [2.434(1)], Rh1-C2 ) 1.906(3)
[1.931(3)], Rh1-P1 ) 2.317(1) [2.313(1)], Rh1-P2 ) 2.325-
(1) [2.327(1)], O1-C2 ) 1.253(3) [1.211(4)], C2-C3 )
1.512(4) [1.508(5)]; Cl2-Zr1-Rh1 ) 137.96(2) [138.05(2)],
O1-Zr1-Rh1 ) 63.76(5) [63.48(6)], Cl2-Zr1-O1 ) 74.25-
(6) [74.84(6)], Zr1-Rh1-P1 ) 81.21(2) [81.35(2)], Zr1-
Rh1-P2 ) 81.40(2) [81.19(2)], Zr1-Rh1-C2 ) 66.08(9)
[65.28(9)], Zr1-Rh1-Cl1 ) 125.79(2) [127.72(2)], P1-
Rh1-P2 ) 160.45(3) [160.44(3)], P1-Rh1-C2 ) 90.81(8)
[90.73(8)], P1-Rh1-Cl1 ) 92.40(3) [92.98(3)], P2-Rh1-
C2 ) 90.25(8) [89.93(9)], P2-Rh1-Cl1 ) 90.56(3) [90.76(3)],
C2-Rh1-Cl1 ) 168.06(10) [166.91(9)], Zr1-O1-C2 )
105.1(2) [105.6(2)], O1-C2-C3 ) 114.7(3) [115.3(3)], O1-
C2-Rh1 ) 125.0(2) [125.3(2)], C3-C2-Rh1 ) 120.4(2)
[119.3(2)].
Complex 12c shows an analogous structure in the
crystal, only that two crystallographically independent
molecules were observed (bonding parameters of the
second molecule are listed in brackets). In 12c the Zr-
Rh bond length amounts to 2.980(1) Å [2.983(1) Å], and
the Rh-carbon bond to the (Zr-Rh) µ-acetyl ligand is
1.906(3) Å (Rh-C2; see Figure 6) [1.931(3) Å]. The acetyl
CdO bond length in 12c amounts to 1.253(3) Å [1.211-
(4) Å]. Again, the coordination geometry at Rh is square
planar (Rh-P1 ) 2.317(1) Å [2.313(1) Å], Rh-P2 )
2.325(1) Å [2.327(1) Å], Rh-Cl1 ) 2.440(1) Å [2.434(1)
Å]; angles C2-Rh-Cl1 ) 168.06(10)° [166.91(9)°], P1-
Rh-P2 ) 160.45(3)° [160.44(3)°]). The Zr-O1 bond
length in 12c is 2.211(2) Å [2.213(2) Å], and the Cl2-
Zr-O1 σ-bond angle was found at 74.25(6)° [74.86(6)°]
(Zr-Cl2 ) 2.551(1) Å [2.553(1) Å]). In 12c the Zr-C(Cp)
bond lengths are also found in a rather small range
between 2.479(3) and 2.542(3) Å [2.466(3)-2.546(3) Å].
In solution complex 12b is characterized by a very
signal of complex 12c was located at δ 2.45 (in d2-
dichloromethane at 298 K).
Some Conclusions
The metal-metal-bonded framework of the heterobi-
metallic complexes 7-12 behaves like an array of metal
atoms that cooperatively determine the reactivity of
their coordinated σ ligands by their special electronic
features and at the same time influence the equilibrium
of potential coupling or dissociation products. The
observed reactions indicate that ligand dissociation from
rhodium inside the heterodimetallic Zr-Rh complexes
is easily achieved. It is probably much facilitated by a
stabilization of Rh in the product by neighboring-group
participation of the [Zr]-CH3 ligand (potentially the
rate of ligand dissociation is increased by anchimeric
assistance by the H3C-[Zr] group). Principally, this
process can lead to CO cleavage from rhodium to yield
the stable product 11, which is observed, or alternatively
to PPh3 liberation. The primary product (13) of the
1
typical 13C NMR µ-acyl resonance at δ 290.3 (dt, JRhC
2
1
) 30.6 Hz, JPC ) 8.1 Hz; 12c, δ 289.0, JRhC ) 23
Hz).27,28 The ligand framework of 12b shows a 31P NMR
resonance at δ 27.5 (1JRhP ) 127.6 Hz; 12c, δ 19.7) and
it features again the typical sets of four C5H4 1H NMR
multiplets (δ 6.49, 6.34, 6.00, 5.90) and the resonances
of two pairs of diastereotopic isopropyl methyl groups
(δ 1.53, 1.50, 1.35, 1.32). The OC(CH3) 1H/13C NMR
signals of complex 12b were monitored at δ 2.47/40.4
(1JCH ) 127.4 Hz). The corresponding COCH3 1H NMR
(28) Kreiter, C. G.; Franzreb, K.-H.; Sheldrick, W. S. J. Organomet.
Chem. 1984, 270, 71-79. Erker, G.; Lecht, R.; Tsay, Y.-H.; Kru¨ger, C.
Chem. Ber. 1987, 120, 1763-1765. Adams, H.; Bailey, N. A.; Mann,
B. E.; Manuel, C. P. Inorg. Chim. Acta 1992, 198, 111-118. Torkelson,
J. R.; Antwi-Nsiah, F. H. McDonald, R.; Cowie, M.; Pruis, J. G.;
Jalkanen, K. J.; DeKock, R. L. J. Am. Chem. Soc. 1999, 121, 3666-
3683. Nombel, P.; Lugan, N.; Donnadieu, B.; Lavigne, G. Organome-
tallics 1999, 18, 187-196. Jime´nez, M. V.; Sola, E.; Egea, M. A.; Huet,
A.; Francisco, A. C.; Lahoz, F. J.; Oro, L. A. Inorg. Chem. 2000, 39,
4868-4878. McConnell, A. E. C.; Foster, D. F.; Pogorzelec, P.; Slawin,
A. M. Z.; Law, D. J.; Cole-Hamilton, D. J. Dalton 2003, 510-512.
Trepanier, S. J.; McDonald, R.; Cowie, M. Organometallics 2003, 22,
2638-2651.
(26) Durfee, L. D.; Rothwell, I. P. Chem. Rev. 1988, 88, 1059-1079.
Adams, H.; Bailey, N. A.; Mann, B. E. Manuel, C. P.; Spencer, C. M.;
Kent, A. G. J. Chem. Soc., Dalton Trans. 1988, 489-496. He, X.;
Maisonnat, A.; Dahan, F.; Poilblanc, R. New J. Chem. 1990, 14, 313-
315. Gonsalvi, L.; Adams, H.; Sunley, G. J.; Ditzel, E.; Haynes, A. J.
Am. Chem. Soc. 2002, 124, 13597-13612.
(27) Christou, V.; Wuller, S. P.; Arnold, J. J. Am. Chem. Soc. 1993,
115, 10545-10552. Guo, Z.; Swenson, D. C.; Guram, A. S.; Jordan, R.
F. Organometallics 1994, 13, 766-773.

Metal-Metal-Bonded Early-Late Heterobimetallics
Organometallics, Vol. 24, No. 2, 2005 221
Scheme 7
Chart 2
analyses were performed with a Foss-Heraeus CHN-O-Rapid
instrument, and a Nicolet 5DXC FT-IR-spectrometer was used
for IR spectra. NMR spectra were measured using a Bruker
AC 200 P or a Varian Unity Plus 600 NMR spectrometer. Most
assignments were based on a series of 2D NMR experiments.
Numbering used for listing of the NMR data is depicted in
Chart 2.
X-ray Crystal Structure Analysis. Data sets were col-
lected with Enraf-Nonius CAD4 and Nonius KappaCCD dif-
fractometers, equipped with a Nonius FR591 rotating anode
generator. Programs used: data collection EXPRESS29 and
COLLECT,30 data reduction MolEN31 and Denzo-SMN,32 ab-
sorption correction for CCD data SORTAV,33 structure solution
SHELXS-97,34 structure refinement SHELXL-97,35 graphics
DIAMOND36 and SCHAKAL.37
competing phosphine cleavage pathway from 7 was not
observed as a stable product in our reaction systems,
but it is likely to occur. It is reasonable to assume that
this reactive intermediate has picked up a CO molecule
from the solution (or from 7) with formation of the
observed (Zr-Rh) dicarbonyl complex 10 (see Scheme
7).
The formation of the µ-acetyl (Zr-Rh) products (12)
upon treatment of 7 with CH2Cl2 is likely to also proceed
via such a reactive intermediate. It is quite conceivable
that migratory CO insertion is likely to occur at the
stage of 13 to eventually lead to a reactive µ-acetyl (Zr-
Rh) species (14) that is able to pick up two chlorine
atoms from the solvent to yield the stable complexes 12.
Although we were not yet able to identify the corre-
sponding organic products, this pathway seems to be
so highly effective that it completely overrides the
otherwise predominant equilibration of 7 with the
products 10 and 11.
Our observations show that the reactions between
fundamental small organic building blocks attached to
the metal components of a ligand-stabilized (but not
ligand-dominated) pair of early-late metals across the
Zr-Rh metal-metal bond has a strong cooperative
moment, similar as it may be at a variety of heteroge-
neous metal-induced reaction systems that involve
combinations of metal components. In these easily
available molecular models of such systems, we may be
able to study fundamental reaction steps by very direct
analytical techniques that might be of value for under-
standing more complex reaction cascades at mixed-
metal compounds, and potentially we will see whether
novel reaction pathways of organic intermediates can
be induced if they are allowed to react at such metal-
metal-bonded templates. The synthetic technique that
we have used for the generation of the heterobimetallic
complexes described and discussed in this article may
make such systems readily available.
Preparation of Bis[η5-(diphenylphosphino)cyclopen-
tadienyl]dimethylzirconium (5a). Methyllithium (19.7 mL,
31.6 mmol, 1.6 M in diethyl ether) was slowly added to a
stirred solution of bis[η5-(diphenylphosphino)cyclopentadienyl]-
dichlorozirconium (9a; 9.45 g, 14.3 mmol) in toluene (100 mL)
at -78 °C. Over 30 min the temperature was raised to 0 °C,
and stirring was continued for 2 h at room temperature. The
resulting slurry was filtered over a bed of Celite, and the
volume was reduced to 5 mL. After the addition of pentane
(50 mL) the product was collected by filtration, washed three
times with pentane, and dried in vacuo to yield 7.45 g (12.0
mmol, 84%) of compound 5a. 1H NMR (CD2Cl2, 200.13 MHz):
δ 7.32 (m, 20H, C6H5), 6.12 (m, 4H, C5H4), 5.98 (m, 4H, C5H4),
-0.41 (s, 6H, Zr-CH3). 31P{1H} NMR (CD2Cl2, 81.0 MHz): δ
-18.9 (s, PPh2).
Preparation of Bis[η5-(diisopropylphosphino)cyclo-
pentadienyl]dimethylzirconium (5b). Methyllithium (19.3
mL, 30.9 mmol, 1.6 M in diethyl ether) was slowly added to a
stirred solution of bis[η5-(diisopropylphosphino)cyclopentadienyl]-
dichlorozirconium (9b; 7.16 g, 13.6 mmol) in toluene (100 mL)
at -78 °C. Over 30 min the temperature was raised to 0 °C,
and stirring was continued for 2 h at room temperature. The
resulting slurry was filtered over a bed of Celite, and the
solvent was removed in vacuo. The residue was dissolved in
pentane (3 mL) and stored at -30 °C for one night. Precooled
perfluoromethylcyclohexane (30 mL) was added at -30 °C, and
the microcrystalline product was collected by filtration, washed
with perfluoromethylcyclohexane, and dried in vacuo to yield
5.88 g (12.2 mmol, 89%) of compound 5b. Single crystals were
obtained by cooling a concentrated solution in heptane to -20
°C for 2 days. Mp: 218 °C dec. Anal. Calcd for C24H42P2Zr
(483.8): C, 59.59; H, 8.75. Found: C, 59.21; H, 8.63. 1H NMR
(CD2Cl2, 599.11 MHz): δ 6.30 (ps t, 4H, 3-H), 6.20 (m, 4H,
2-H), 1.95 (sept d, 3JHH ) 7.1 Hz, 2JPH ) 1.4 Hz, 4H, CH), 1.12
3
3
3
(dd, JPH ) 13.6 Hz, JHH ) 7.1 Hz, 12H, CH3), 0.92 (dd, JPH
(29) EXPRESS; Nonius BV, 1994.
(30) COLLECT; Nonius BV, 1998.
(31) Fair, K. MolEN; Enraf-Nonius BV, 1990.
(32) Otwinowski, Z.; Minor, W. Methods Enzymol. 1997, 276, 307-
326.
(33) Blessing, R. H. Acta Crystallogr. 1995, A51, 33-37. Blessing,
R. H. J. Appl. Crystallogr. 1997, 30, 421-426.
(34) Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467-473.
(35) Sheldrick, G. M. Universita¨t Go¨ttingen, Go¨ttingen, Germany,
1997.
(36) Brandenburg, K. Universita¨t Bonn, Bonn, Germany, 1997.
(37) Keller, E. Universita¨t Freiburg, Freiburg, Germany, 1997.
Experimental Section
General Considerations. All reactions were carried out
under argon using Schlenk-type glassware or in a glovebox.
Solvents, including deuterated solvents used for NMR spec-
troscopy, were dried and distilled prior to use. Elemental

222 Organometallics, Vol. 24, No. 2, 2005
Cornelissen et al.
1
) 12.2 Hz, 3JHH ) 7.1 Hz, 12H, CH3), -0.32 (s, 6H, Zr-CH3).
(d, JPC ) 35.1 Hz, C-1), 117.5 (m, C-2), 114.6 (m, C-3), (m,
1
1
13C{1H} NMR (CD2Cl2, 150.6 MHz): δ 118.4 (d, JPC ) 24.6
33.4 (d, JPC ) 22.1 Hz, C(CH3)3), 33.1 (s, Zr-CH3), 30.9 (d,
Hz, C-1), 115.5 (m, C-2), 114.1 (m, C-3), 32.2 (t, JPC ) 3.4 Hz,
Zr-CH3), 24.0 (d, 1JPC ) 12.8 Hz, CH), 20.2 (d, 2JPC ) 3.0 Hz,
CH3), 20.1 (d, 2JPC ) 6.0 Hz, CH3). 31P{1H} NMR (CD2Cl2, 81.02
MHz): δ 2.3 (s, P(i-Pr)2).
2JPC ) 13.7 Hz, C(CH3)3). 31P{1H} NMR (CD2Cl2, 81.02 MHz):
δ 31.7 (s, P(tBu)2).
Reaction of (Cp-PPh2)2Zr(CH3)2 (5a) with HRh(CO)-
(PPh3)3 (6). Formation of 7a. Precooled dichloromethane (1
mL) was added to a mixture of 5a (62 mg, 0.10 mmol) and 6
(92 mg, 0.10 mmol) at room temperature. The color changed
to dark red, and gas evolution occurred. After 30 min the
solvent was removed in vacuo and the solid was extracted with
pentane for 2 days to yield 35 mg (0.04 mmol, 40%) of
compound 7a as a brown powder. Single crystals were obtained
by slow evaporation of the solvent of a solution in toluene. 1H
NMR (CD2Cl2, 200.13 MHz): δ 7.43-7.02, 6.85 (2 m, 35H,
C6H5), 6.62 (s, 2H, C5H4), 6.40 (m, 2H, C5H4), 5.31 (m, 2H,
C5H4), 4.11 (s, 2H, C5H4), -0.82 (s, 3H, CH3). 31P{1H} NMR
(CD2Cl2, 81.02 MHz): δ 45.5 (dt, 1JRhP ) 110.3 Hz, 2JPP ) 36.5
X-ray Crystal Structure Analysis for 5b: formula
C24H42P2Zr, Mr ) 483.74, colorless crystal 0.40 × 0.25 × 0.15
mm, a ) 8.680(2) Å, b ) 11.311(1) Å, c ) 14.041(2) Å, R )
89.14(1)°, â ) 87.76(1)°, γ ) 67.47(1)°, V ) 1272.4(4) Å3, Fcalcd
) 1.263 g cm-3, µ) 5.65 cm-1, no absorption correction (0.806
e T e 0.920), Z ) 2, triclinic, space group P1h (No. 2), λ )
0.710 73 Å, T ) 223 K, ω/2θ scans, 5518 reflections collected
(+h, (k, (l), (sin θ)/λ ) 0.62 Å-1, 5162 independent (Rint
)
0.021) and 4309 observed reflections (I g 2σ(I)), 254 refined
parameters, R1 ) 0.066, wR2 ) 0.215, maximum (minimum)
residual electron density 1.75 (-1.97) e Å-3, hydrogen atoms
calculated and refined as riding atoms.
1
2
Hz, PPh3), 26.1 (dd, JRhP ) 161.3 Hz, JPP ) 36.5 Hz, PPh2).
Preparation of Bis[η5-(dicyclohexylphosphino)cyclo-
pentadienyl]dimethylzirconium (5c). Methyllithium (13.0
mL, 20.8 mmol, 1.6 M in diethyl ether) was slowly added to a
stirred solution of bis[η5-(dicyclohexylphosphino)cyclopen-
tadienyl]dichlorozirconium (9c; 6.46 g, 9.4 mmol) in toluene
(100 mL) at -78 °C. Over 30 min the temperature was raised
to 0 °C, and stirring was continued for 1 h at 0 °C. The
resulting slurry was filtered over a bed of Celite, and the
solvent was removed in vacuo. After the addition of pentane
(20 mL) the product was collected by filtration, washed with
three small portions of pentane, and dried in vacuo to yield
5.00 g (7.8 mmol, 82%) of compound 5c. Single crystals were
obtained by cooling a concentrated solution in toluene to -30
°C for 1 day. Mp: 237 °C dec. Anal. Calcd for C36H58P2Zr
(644.0): C, 67.14; H, 9.08. Found: C, 66.78; H, 8.69. 1H NMR
(CD2Cl2, 400.14 MHz): δ 6.28 (ps t, 4H, 3-H), 6.18 (ps t, 4H,
2-H), 1.89-1.56 (m, 24H, C6H11), 1.36-1.21 (m, 16 H, C6H11),
0.95 (m, 4 H, C6H11), -0.34 (s, 6H, Zr-CH3). 13C{1H} NMR
(CD2Cl2, 100.63 MHz): δ 118.6 (d, 1JPC ) 23.3 Hz, C-1), 115.9
(m, C-2), 114.1 (m, C-3), 34.2 (d, JPC ) 12.9 Hz, C6H11), 31.8
(t, 3JPC ) 3.6 Hz, Zr-CH3), 31.1 (d, JPC ) 12.9 Hz, C6H11), 30.7
(d, JPC ) 12.9 Hz, C6H11), 27.9 (d, JPC ) 10.1 Hz, C6H11), 27.7
(d, JPC ) 9.1 Hz, C6H11), 26.9 (s, C6H11). 31P{1H} NMR (CD2-
Cl2, 80.02 MHz): δ -6.1 (s, PCy2).
IR (CH2Cl2): νj(CO) 1977 cm-1
.
X-ray Crystal Structure Analysis for 7a: formula C54H46-
OP3RhZr, Mr ) 997.95, red crystal 0.15 × 0.10 × 0.05 mm, a
) 24.970(1) Å, b ) 12.621(1) Å, c ) 28.554(1) Å, V ) 8998.7(9)
Å3, Fcalcd ) 1.473 g cm-3, µ ) 7.44 cm-1, empirical absorption
correction (0.897 e T e 0.964), Z ) 8, orthorhombic, space
group Pca21 (No. 29), λ ) 0.710 73 Å, T ) 198 K, ω and æ scans,
61 070 reflections collected ((h, (k, (l), (sin θ)/λ ) 0.62 Å-1
,
17 442 independent (Rint ) 0.086) and 12 617 observed reflec-
tions (I g 2σ(I)), 1083 refined parameters, R1 ) 0.051, wR2 )
0.082, maximum (minimum) residual electron density 0.53
(-0.42) e Å-3, hydrogen atoms calculated and refined as riding
atoms, two almost identical molecules in the asymmetric unit,
crystal seems to be a racemic twin.
Reaction of (Cp-P(i-Pr)2)2Zr(CH3)2 (5b) with HRh(CO)-
(PPh3)3 (6). Formation of 7b, 10b, and 11b. Precooled d8-
toluene (1 mL) was added to a mixture of 5b (22 mg, 45.4 µmol)
and 6 (42 mg, 45.4 µmol) at room temperature. The color
changed to brownish dark red, and gas evolution occurred.
After 5 min the solvent of the crude mixture was removed and
the residue washed with pentane (0.5 mL) and dried in vacuo
to yield 11 mg of a brown powder. If the crude mixture was
stored at room temperature for a few weeks or heated to
elevated temperatures, disproportionation of 7b to 10b and
11b can be observed via NMR experiment.
Data for 7b are as follows. Anal. Calcd for C42H54OP3-
RhZr‚0.6C18H15P (1019.3): C, 62.21; H, 6.23. Found: C, 62.37;
H, 5.88. 1H NMR (C7D8, 599.11 MHz, 298 K): δ 7.35 (br s,
18H, C6H5), 6.99 (m, 27H, C6H5), 6.64 (br, 2H, 2-H), 6.10 (m,
2H, 3-H), 4.86 (m, 2H, 4-H), 4.22 (br, 2H, 5-H), 2.37 (sept., J
) 7.2 Hz, 2H, 9-H), 1.65 (sept., J ) 7.0, 2H, 6-H), 1.21 (ps q,
6H, 10-H), 1.18 (ps q, 6H, 11-H), 1.09 (ps q, 6H, 7-H), 0.93 (ps
q, 6H, 8-H), -0.49 (m, 3H, Zr-CH3). 13C{1H} NMR (C7D8, 150.7
MHz, 298 K): δ 194.7 (CO, resonance acquired from the 1H-
13C ghmbc experiment), 134.2 (d, J ) 17.8 Hz, C6H5), 128.5
(br s, C6H5), 115.9 (s, C-3), 114.3 (t, J ) 4.5 Hz, C-2), 107.3
(m, C-4), 106.2 (ps t, C-1), 100.6 (m, C-5), 30.5, 30.4
(C-6, C-9), 28.9 (Zr-CH3), 22.0 (C-7), 21.6 (C-10), 20.1 (t, J )
3.2 Hz, C-8), 19.7 (C-11) (some 13Carom resonances are not listed
due to the complexity of the 13C NMR spectra). 31P{1H} NMR
X-ray Crystal Structure Analysis for 5c: formula
C36H58P2Zr, Mr ) 643.98, colorless crystal 0.35 × 0.35 × 0.30
mm, a ) 10.269(1) Å, b ) 14.541(1) Å, c ) 23.755(1) Å, â )
99.39(1)°, V ) 3499.6(4) Å3, Fcalcd ) 1.222 g cm-3, µ) 4.27 cm-1
,
empirical absorption correction (0.865 e T e 0.883), Z ) 4,
monoclinic, space group C2/c (No. 15), λ ) 0.710 73 Å, T )
198 K, ω and æ scans, 15 483 reflections collected ((h, (k,
(l), (sin θ)/λ ) 0.68 Å-1, 4292 independent (Rint ) 0.028) and
3723 observed reflections (I g 2σ(I)), 178 refined parameters,
R1 ) 0.031, wR2 ) 0.072, maximum (minimum) residual
electron density 0.32 (-0.46) e Å-3, hydrogen atoms calculated
and refined as riding atoms.
Preparation of Bis[η5-(di-tert-butylphosphino)cyclo-
pentadienyl]dimethylzirconium (5d). Methyllithium (4.5
mL, 7.26 mmol, 1.6 M in diethyl ether) was slowly added to a
stirring solution of bis[η5-(di-tert-butylphosphino)cyclopenta-
dienyl]dichlorozirconium (9d; 1.88 g, 3.2 mmol) in toluene (50
mL) at -78 °C. Over 30 min the temperature was raised to 0
°C and stirring was continued for 1 h at 0 °C. The resulting
slurry was filtered over a bed of Celite, and the solvent was
removed in vacuo. After the residue was dissolved in pentane
(5 mL), perfluoromethylcyclohexane (20 mL) was added and
the product was collected by filtration, washed with perfluo-
romethylcyclohexane, and dried in vacuo to yield 1.37 g (2.54
mmol, 78%) of compound 5d. Mp: 96 °C. Anal. Calcd for
C28H50P2Zr (539.9): C, 62.29; H, 9.34. Found: C, 62.54; H, 8.89.
1H NMR (CD2Cl2, 599.11 MHz): δ 6.39 (m, 4H, C5H4), 6.36
1
(C7D8, 242.53 MHz, 298 K): δ 47.2 (br s, PPh3), 33.9 (d, JRhP
) 154.3 Hz, P(i-Pr)2). IR (toluene): νj(CO) 1879 cm-1
.
1
Data for 11b are as follows. H NMR (C7D8, 599.11 MHz,
298 K): δ 6.00 (m, 2H, 2-H), 5.91 (m, 2H, 3-H), 5.50 (m, 2H,
5-H), 4.75 (m, 2H, 4-H), 2.44 (m, 2H, 6-H), 2.02 (m, 2H, 9-H),
1.41 (m, 6H, 7-H), 1.38 (m, 6H, 8-H), 1.13 (m, 6H, 10-H), 0.93
(m, 6H, 11-H), -0.35 (d, 3JPH ) 3.2 Hz, 3H, CH3). 13C{1H} NMR
(C7D8, 150.6 MHz, 298 K): δ 116.5 (m, C-1), 114.4 (m, C-2),
112.6 (m, C-3), 109.1 (m, C-4), 103.1 (m, C-5), 32.1 (m, C-6),
30.4 (m, C-9), 23.1 (m, C-7), 21.7 (m, C-8), 20.6 (m, C-10), 19.7
(m, C-11), 14.2 (m, CH3). 31P{1H} NMR (C7D8, 81.02 MHz, 298
3
(m, 4H, C5H4), 1.14 (d, JPH ) 11.2 Hz, 36H, C(CH3)3), -0.27
(s, 6H, Zr-CH3). 13C{1H} NMR (CD2Cl2, 150.6 MHz): δ 120.4
K): δ 33.6 (d, JRhP ) 188.4 Hz, P(i-Pr)2).
1

Metal-Metal-Bonded Early-Late Heterobimetallics
Organometallics, Vol. 24, No. 2, 2005 223
Reaction of (Cp-PCy2)2Zr(CH3)2 (5c) with HRh(CO)-
(PPh3)3 (6) in Toluene. Formation of 7c, 10c, and 11c.
Precooled (-30 °C) d8-toluene was added to a stirred mixture
of 5c (64 mg, 0.1 mmol) and 6 (92 mg, 0.1 mmol) at room
temperature. After one night complex 10c occurs as a dark
red crystalline material. The supernatant solution contains the
compounds 10c, 7c, and 11c in a ratio of 1:11:16 and
triphenylphosphine. The solid was collected by filtration,
washed twice with toluene (0.5 mL each), and dried in vacuo
to yield 25 mg (28 µmol, 56%) of compound 10c.
pentane, and the product was collected by filtration, washed
three times with pentane, and dried in vacuo.
Preparation of Lithium (Diphenylphosphino)cyclo-
pentadienide (8a). Following the general procedure freshly
distilled chlorodiphenylphosphine (31.71 mL, 38.18 g, 0.18 mol)
was reacted with lithium cyclopentadienide (12.73 g, 0.18 mol)
and subsequently with n-butyllithium (110.3 mL, 0.18 mol,
1.6 M in hexane) to yield 36.38 g (0.14 mol, 80%) of compound
8a. 1H NMR (d8-THF, 200.13 MHz): δ 7.35-7.20 (m, 4H,
o-C6H5), 7.20-7.00 (m, 6H, m-C6H5 and p-C6H5), 6.00-5.93 (m,
4H, C5H4). 31P{1H} NMR (d8-THF, 81.02 MHz): δ -18.8 (s,
PPh2).
Carbonyl[bis(η5-(dicyclohexylphosphino)cyclopen-
tadienyl)methylzirconium-K2P,P′](triphenylphosphine)-
rhodium (Rh-Zr) (7c). 1H NMR (C7D8, 599.11 MHz, 298
K): δ 6.81 (s, 2H, 2-H), 6.20 (s, 2H, 3-H), 4.91 (m, 2H, 4-H),
4.32 (m, 2H, 5-H), 2.52 (m, 4H, 6-H + CyB), 2.13 (m, 2H, CyA),
2.03 (m, 2H, CyB), 1.69 (m, 4H, CyA + CyB), 1.59 (m, 2H, CyA),
1.56 (m, 2H, CyB), 1.53 (m, 4H, CyA), 1.47 (m, 2H, CyB), 1.41
(m, 2H, CyB), 1.32 (m, 2H, CyA), 1.25 (m, 4H, CyB), 1.11 (m,
2H, CyA), 1.10 (m, 2H, 6-H), 1.07 (m, 2H, CyA), 1.05 (m, 2H,
CyB), 1.04 (m, 2H, CyA), 1.00 (m, 2H, CyA), 0.94 (m, 2H, CyB),
-0.42 (s, 3H, CH3). 13C{1H} NMR (C7D8, 150.6 MHz, 298 K):
δ 116.6 (s, C-3), 114.2 (m, C-2), 107.2 (m, C-1), 106.7 (m, C-4),
100.4 (m, C-5), 44.2 (m, C-6), 43.4 (m, C-7), 32.9 (s, CyA), 30.9
(m, CyB), 30.5 (m, CyB), 30.1 (m, CyA), 29.2 (m, CyA), 29.1 (m,
CyA), 29.0 (s, CH3), 28.7 (m, CyB), 27.8 (m, CyB), 27.1 (m, CyA),
26.8 (m, CyB). 31P{1H} NMR (C7D8, 242.53 MHz, 298 K): δ
Preparation of Lithium (Diisopropylphosphino)cy-
clopentadienide (8b). Following the general procedure chlo-
rodiisopropylphosphine (21.65 g, 0.14 mol) was reacted with
lithium cyclopentadienide (9.81 g, 0.14 mol) and subsequently
with n-butyllithium (9.81 g, 0.14 mol, 1.6 M in hexane) to yield
21.94 g (0.12 mmol, 86%) of compound 8b. Mp: 81 °C. Anal.
Calcd for C11H18PLi (188.2): C, 70.21; H, 9.64. Found: C,
69.46; H, 9.57. 1H NMR (C6D6, 200.13 MHz): δ 5.74 (ps s, 4H,
3
2
C5H4), 1.87 (sept d, JHH ) 7.0 Hz, JPH ) 2.7 Hz, 2H, CH),
1.12 (dd, 3JHH ) 7.0 Hz, 3JPH ) 1.0 Hz, 6H, CH3), 1.06 (d, 3JHH
) 7.0 Hz, 6H, CH3). 13C{1H} NMR (C6D6, 50.32 MHz): 111.7
(d, 2JPC ) 9.1 Hz, C-2), 109.7 (d, 1JPC ) 7.4 Hz, C-1), 106.6 (d,
1
2
3JPC ) 5.8 Hz, C-3), 23.6 (d, JPC ) 9.1 Hz, CH), 20.6 (d, JPC
) 28.2 Hz, CH3) 20.4 (d, JPC ) 30.7 Hz, CH3). 31P{1H} NMR
2
(C6D6, 81.02 MHz): δ 0.1 (s, P(iPr)2). 31P{1H} NMR (d8-THF,
81.02 MHz): δ 3.1 (s, P(iPr)2).
1
49.9 (very broad, PPh3), 23.0 (d, JRhP ) 152.7 Hz, PCy2).
Bis(carbonyl)[bis(η5-(dicyclohexylphosphino)cyclo-
pentadienyl)methylzirconium-K2 P,P′]rhodium (Rh-Zr)
(10c). Anal. Calcd for C37H55O2P2RhZr (787.9): C, 56.40; H,
Preparation of Lithium (Dicyclohexylphosphino)cy-
clopentadienide (8c). Following the general procedure chlo-
rodicyclohexylphosphine (10.43 mL, 10.99 g, 47.0 mmol) was
reacted with lithium cyclopentadienide (3.39 g, 47.0 mmol) and
subsequently with n-butyllithium (29.4 mL, 47.0 mol, 1.6 M
in hexane) to yield 12.43 g (46.3 mmol, 99%) of compound 8c.
Mp: 213 °C. Anal. Calcd for C17H26LiP (268.3): C, 76.10; H,
9.77. Found: C, 75.85; H, 10.28. 1H NMR (d8-THF, 200.13
MHz): δ 5.90 (m, 2H, C5H4), 5.84 (m, 2H, C5H4), 1.69, 1.36-
1.01 (2 m, 22H, C6H11). 13C{1H} NMR (d8-THF, 50.32 MHz):
δ 107.4 (d, 2JPC ) 17.8 Hz, C-2), 100.8 (d, 3JPC ) 7.5 Hz, C-3),
1
7.04. Found: C, 56.76; H, 6.75. H NMR (C7D8, 599.11 MHz,
298 K): δ 6.37 (br m, 2H, 2-H), 6.07 (br m, 2H, 3-H), 4.83 (br
m, 2H, 4-H), 3.95 (br m, 2H, 5-H), 2.59 (br m, 2H, Cy), 2.34
(m, 2H, Cy), 2.20-1.03 (m, 40H, Cy), -0.76 (br s, 3H, CH3).
31P{1H} NMR (C7D8, 81.02 MHz): δ 46.8 (d, 1JRhP ) 149.4 Hz,
PCy2). IR (KBr): νj(CO) 1930, 1862 cm-1
.
[Bis(η5-(dicyclohexylphosphino)cyclopentadienyl)zir-
conium-K2 P,P′](µ-methyl)(triphenylphosphine)rhodium
1
(Rh-Zr) (11c). H NMR (C7D8, 599.11 MHz, 298 K): δ 7.45
1
99.7 (d, JPC ) 5.1 Hz, C-1), 30.0 (d, JPC ) 12.7 Hz, C6H11),
(m, 6H, o-C6H5), 7.04 (m, 6H, m-C6H5), 6.96 (m, 3H, p-C6H5),
6.09 (m, 2H, 2-H), 5.94 (m, 2H, 3-H), 5.61 (m, 2H, 5-H), 4.84
(m, 2H, 4-H), 2.37 (m, 2H, Cy, resonances are acquired from
26.7 (d, JPC ) 17.8 Hz, C6H11), 25.5 (d, JPC ) 10.2 Hz, C6H11),
23.6 (d, JPC ) 15.2 Hz, C6H11), 23.5 (s, C6H11), 22.8 (s, C6H11).
31P{1H} NMR (d8-THF, 81.02 MHz): δ -11.8 (s, PCy2).
Preparation of Lithium (Di-tert-butylphosphino)cy-
clopentadienide (8d). Following the general procedure chlo-
rodi-tert-butylphosphine (5.49 g, 29.2 mmol) was reacted with
sodium cyclopentadienide (2.57 g, 29.2 mmol) and subse-
quently with n-butyllithium (18.3 mL, 29.2 mol, 1.6 M in
hexane) to yield 1.49 g (6.9 mmol, 24%) of compound 8d. Mp:
224 °C. Anal. Calcd for C13H22LiP (216.2): C, 72.21; H, 10.26.
Found: C, 71.89; H, 10.14. 1H NMR (d8-THF, 200.13 MHz): δ
1
1
the H-1H TOCSY and the two-dimensional H-13C correla-
tion experiments), 2.25 (m, 4H, CyA + CyB), 2.14 (m, 2H, 6-H),
1.96 (m, 2H, 7-H), 1.85 (m, 2H, CyA), 1.80 (m, 2H, CyB), 1.77
(m, 2H, CyA), 1.72 (m, 2H, CyA), 1.62 (m, 2H, CyA), 1.61 (m,
2H, CyB), 1.56 (m, 2H, CyA), 1.51 (m, 2H, CyB), 1.39 (m, 6H,
CyA + CyB), 1.25 (m, 2H, CyA), 1.23 (m, 2H, CyB), 1.22 (m, 2H,
CyA), 1.00 (m, 2H, CyB), 0.98 (m, 2H, CyB), 0.65 (m, 2H, CyB),
-0.29 (d, 3JPH ) 3.4 Hz, 3H, CH3). 13C{1H} NMR (C7D8, 150.6
1
3
MHz, 298 K): δ 140.3 (m, i-C6H5), 133.7 (d, JPC ) 15.3 Hz,
6.03 (m, 2H, C5H4), 5.84 (m, 2H, C5H4), 1.12 (d, JPH ) 10.6
Hz, 18H, CH3). 13C{1H} NMR (d8-THF, 50.32 MHz): δ 114.6
o-C6H5), 128.2 (m, m-C6H5), 125.4 (s, p-C6H5), 115.4 (m, C-1),
114.7 (m, C-2), 112.5 (m, C-3), 108.9 (m, C-4), 103.2 (m, C-5),
44.6 (m, C-6), 41.9 (m, C-7), 34.0 (m, CyA), 31.6 (m, CyA), 31.2
(m, CyB), 29.7 (m, CyB), 29.2 (m, CyA), 28.7 (m, CyA + CyB),
1
(d, JPC ) 21.5 Hz, C5H4), 106.7 (d, JPC ) 9.9 Hz, C-1), 105.4
(d, JPC ) 8.2 Hz, C5H4), 32.6 (d, 1JPC ) 21.6 Hz, C(CH3)3), 31.5
2
(d, JPC ) 14.9 Hz, C(CH3)3). 31P{1H} NMR (d8-THF, 81.02
1
27.8 (m, CyB), 27.0 (m, CyA + CyB), 14.4 (s, JCH ) 120.7 Hz,
MHz): δ 25.3 (s, P(tBu)2).
CH3). 31P{1H} NMR (C7D8, 242.53 MHz, 298 K): δ 34.5 (dt,
1JRhP ) 164.4 Hz, 2JPP ) 25.2 Hz, PPh3), 26.3 (dd, 1JRhP ) 196.1
Phosphino-Substituted Zirconocene Dichlorides 9.
General Procedure. A Schlenk flask was charged with
phosphino-substituted cyclopentadienide (10 mmol) and zir-
conium tetrachloride (5 mmol). After the addition of precooled
toluene (50 mL) and THF (0.2 mL) at -78 °C, the solution
was warmed to room temperature overnight. The resulting
slurry was filtered over a bed of Celite, and the volume of the
filtrate was reduced to 5 mL. Subsequent addition of pentane
leads to the formation of a slightly yellow precipitate, which
was collected by filtration, washed three times with pentane,
and dried in vacuo.
2
Hz, JPP ) 25.2 Hz, PCy2).
Phosphino-Substituted Cyclopentadienides 8. Gen-
eral Procedure. Chlorophosphine (10 mmol) with the desired
substituents was slowly added to a solution of lithium cyclo-
pentadienide (8a-c; 10 mmol) or sodium cyclopentadienide
(8d; 10 mmol) in THF (10 mL) at -78 °C. The solution was
warmed to room temperature overnight, and the solvent was
removed in vacuo. Toluene (10 mL) was added, and the slurry
was filtered over a bed of Celite. n-Butyllithium (10 mmol, 1.6
M in hexane) was then added to the filtrate at -78 °C. The
solution was warmed to room temperature overnight, and the
solvent was removed in vacuo. The residue was stirred with
Preparation of Bis[η5-(diphenylphosphino)cyclopen-
tadienyl]dichlorozirconium (9a). Following the general
procedure lithium (diphenylphosphino)cyclopentadienide (8a;

224 Organometallics, Vol. 24, No. 2, 2005
Cornelissen et al.
13.00 g, 50.7 mmol) was reacted with zirconium tetrachloride
(5.91 g, 25.4 mmol) to yield 11.54 g (19.3 mmol, 76%) of
compound 9a. Single crystals were obtained by cooling a
concentrated solution in toluene to -30 °C for 1 day. 1H NMR
(CD2Cl2, 599.11 MHz): δ 7.33 (m, 20H, C6H5), 6.39, (m, 4H,
2-H), 6.35 (m, 5H, 3-H). 13C{1H} NMR (CDCl3, 50.32 MHz): δ
136.8 (d, 1JPC ) 12 Hz, i-C6H5), 133.9 (d, 2JPC ) 20 Hz, o-C6H5),
129.3 (s, p-C6H5), 128.5 (d, 3JPC ) 7 Hz, m-C6H5), 125.1 (d, 1JPC
104.75(1)°, V ) 3394.4(4) Å3, Fcalcd ) 1.340 g cm-3, µ ) 5.97
cm-1, empirical absorption correction (0.890 e T e 0.943), Z
) 4, monoclinic, space group P21/c (No. 14), λ ) 0.710 73 Å, T
) 198 K, ω and æ scans, 20 971 reflections collected ((h, (k,
(l), (sin θ)/λ ) 0.65 Å-1, 7781 independent (Rint ) 0.043) and
5796 observed reflections (I g 2σ(I)), 352 refined parameters,
R1 ) 0.047, wR2 ) 0.102, maximum (minimum) residual
electron density 1.71 (-1.08) e Å-3, hydrogen atoms calculated
and refined as riding atoms.
2
) 17 Hz, C-1), 122.1 (d, JPC ) 10 Hz, C-2), 118.2 (s, C-3).
31P{1H} NMR (CD2Cl2, 242.53 MHz, 298 K): δ -17.3 (s, PPh2).
X-ray Crystal Structure Analysis for 9a: formula C34H28-
Cl2P2Zr, Mr ) 660.62, yellow crystal 0.20 × 0.20 × 0.10 mm,
a ) 9.360(1) Å, b ) 12.047(1) Å, c ) 14.230(1) Å, R ) 101.32(1)°,
â ) 97.43(1)°, γ ) 103.58(1)°, V ) 1503.3(2) Å3, Fcalcd ) 1.459
g cm-3, µ ) 6.72 cm-1, empirical absorption correction (0.877
e T e 0.936), Z ) 2, triclinic, space group P1h (No. 2), λ )
0.710 73 Å, T ) 198 K, ω and æ scans, 17 932 reflections
collected ((h, (k, (l), (sin θ)/λ ) 0.60 Å-1, 5269 independent
(Rint ) 0.070) and 3883 observed reflections (I g 2σ(I)), 352
refined parameters, R1 ) 0.054, wR2 ) 0.089, maximum
Preparation of Bis[η5-(di-tert-butylphosphino)cyclo-
pentadienide]dichlorozirconium (9d). Following the gen-
eral procedure lithium (di-tert-butylphosphino)cyclopenta-
dienide (8d; 2.50 g, 11.6 mmol) was reacted with zirconium
tetrachloride (1.35 g, 5.8 mmol) to yield 2.23 g (3.8 mmol, 66%)
of compound 9d. Single crystals were obtained by slow
evaporation of the solvent of a solution in toluene. Mp: 212
°C. Anal. Calcd for C26H44P2Cl2Zr (580.7): C, 53.78; H, 7.64.
1
Found: C, 54.11; H, 7.63. H NMR (CD2Cl2, 200.13 MHz): δ
3
6.94 (m, 4H, C5H4), 6.54 (m, 4H, C5H4), 1.19 (d, JPH ) 11.5
Hz, CH3). 13C{1H} NMR (CD2Cl2, 50.32 MHz): 125.9 (m, C5H4),
118.3 (m, C5H4), 33.8 (d, 1JPC ) 22.1 Hz, C(CH3)3), 30.8 (d, 2JPC
) 14.0 Hz, C(CH3)3), C-1 could not be detected. 31P{1H} NMR
(CD2Cl2, 81.02 MHz): δ 34.4 (s, P(t-Bu)2).
(minimum) residual electron density 0.29 (-0.36) e Å-3
,
hydrogen atoms calculated and refined as riding atoms.
Preparation of Bis[η5-(diisopropylphosphino)cyclo-
pentadienide]dichlorozirconium (9b). Following the gen-
eral procedure lithium (diisopropylphosphino)cyclopentadienide
(8b; 9.50 g, 50.5 mmol) was reacted with zirconium tetrachlo-
ride (5.88 g, 25.2 mmol) to yield 11.54 g (19.3 mmol, 76%) of
compound 9b. Single crystals were obtained by cooling a
concentrated solution in toluene to -30 °C for 1 day. Mp: 118
°C. Anal. Calcd for C22H36Cl2P2Zr (524.6): C, 50.37; H, 6.92.
X-ray Crystal Structure Analysis for 9d: formula C26H44-
Cl2P2Zr‚2CH2Cl2, Mr ) 750.52, light yellow crystal 0.40 × 0.30
× 0.20 mm, a ) 24.693(1) Å, b ) 17.604(1) Å, c ) 8.137(1) Å,
â ) 96.65(1)°, V ) 3513.3(5) Å3, Fcalcd ) 1.419 g cm-3, µ ) 8.78
cm-1, empirical absorption correction (0.720 e T e 0.844), Z
) 4, monoclinic, space group C2/c (No. 15), λ ) 0.710 73 Å, T
) 198 K, ω and æ scans, 13 483 reflections collected ((h, (k,
(l), (sin θ)/λ ) 0.66 Å-1, 4172 independent (Rint ) 0.032) and
3775 observed reflections (I g 2σ(I)), 174 refined parameters,
R1 ) 0.024, wR2 ) 0.061, maximum (minimum) residual
electron density 0.33 (-0.43) e Å-3, hydrogen atoms calculated
and refined as riding atoms.
1
Found: C, 49.50; H, 7.05. H NMR (CD2Cl2, 599.11 MHz): δ
3
6.68 (m, 4H, 2-H), 6.53 (m, 4H, 3-H), 2.05 (sept, JHH ) 7.1
2
3
Hz, 2H, CH), 1.15 (dd, JPH ) 13.7 Hz, JHH ) 7.1 Hz, 6H,
3
1
CH3), 0.99 (dd, JPH ) 12.7 Hz, JHH ) 7.1 Hz, 6H, CH3).
13C{1H} NMR (CD2Cl2, 100.63 MHz): δ 124.9 (d, JPC ) 30.6
1
1
Preparation of Dicarbonyl[bis(η5-(diisopropylphos-
phino)cyclopentadienyl)methylzirconium-K2P,P′]rhod-
ium (Rh-Zr) (10b). Precooled (-30 °C) toluene was added
to a stirred mixture of 5b (22 mg, 45 µmol) and 6 (42 mg, 45
µmol) at room temperature. After 1 min CO was bubbled
through the dark brownish solution until the color stayed dark
red for 2 s. The volume was reduced in vacuo, and the solution
was stored at -30 °C for 2 days. Collection of the solid by
filtration and drying in vacuo yielded 14 mg of compound 10b
as a microcrystalline solid. Anal. Calcd for C25H39O2P2RhZr
(627.7): C, 47.84; H, 6.26. Found: C, 48.46; H, 5.71. 1H NMR
(C7D8, 599.11 MHz, 298 K): δ 6.23 (m, 2H, 2-H), 6.02 (m, 2H,
3-H), 4.80 (m, 2H, 4-H), 3.77 (m, 2H, 5-H), 2.39 (m, 2H, 9-H),
1.48 (m, 6H, 10-H), 1.40 (m, 8H, 6-H, 11-H), 1.14 (m, 6H, 7-H),
1.00 (m, 6H, 8-H), -0.83 (m, 3H, CH3). 13C{1H} NMR (C7D8,
Hz, C-1), 123.5 (m, C-2), 118.4 (m, C-3), 24.2 (d, JPC ) 12.9
2
2
Hz, CH), 20.4 (d, JPC ) 20.1 Hz, CH3), 20.2 (d, JPC ) 23.1
Hz, CH3). 31P{1H} NMR (CD2Cl2, 242.53 MHz): δ 5.1 (s, P(i-
Pr)2).
X-ray Crystal Structure Analysis for 9b: formula C22H36-
Cl2P2Zr, Mr ) 524.57, colorless crystal 0.35 × 0.15 × 0.10 mm,
a ) 8.656(1) Å, b ) 20.384(1) Å, c ) 14.203(1) Å, â ) 93.21-
(1)°, V ) 2502.1(4) Å3, Fcalcd ) 1.393 g cm-3, µ ) 7.87 cm-1
,
empirical absorption correction (0.770 e T e 0.926), Z ) 4,
monoclinic, space group C2/c (No. 15), λ ) 0.710 73 Å, T )
198 K, ω and æ scans, 12 320 reflections collected ((h, (k,
(l), (sin θ)/λ ) 0.66 Å-1, 2981 independent (Rint ) 0.045) and
2538 observed reflections (I g 2σ(I)), 127 refined parameters,
R1 ) 0.030, wR2 ) 0.062, maximum (minimum) residual
electron density 0.24 (-0.54) e Å-3, hydrogen atoms calculated
and refined as riding atoms.
1
2
150.6 MHz, 298 K): δ 213.3 (dt, JRhC ) 60.3 Hz, JPC ) 14.8
Hz, CO), 191.5 (dt, 1JRhC ) 76.6 Hz, 2JPC ) 10.9 Hz, CO), 115.5
(m, C-3), 114.8 (m, C-2), 108.3 (m, C-4), 101.2 (dd, J ) 16.6
Hz, J ) 14.1 Hz, C-1), 100.4 (m, C-5), 30.3 (m, C-6), 30.1 (m,
C-9), 28.9 (m, JCH ) 123 Hz, CH3), 20.8 (m, C-7), 20.7 (m, C-11),
20.3 (m, C-10), 19.6 (m, C-8). 31P{1H} NMR (C7D8, 242.53 MHz,
Preparation of Bis[η5-(dicyclohexylphosphino)cyclo-
pentadienide]dichlorozirconium (9c). Following the gen-
eral procedure lithium (dicyclohexylphosphino)cyclopentadienide
(8c; 8.00 g, 29.8 mmol) was reacted with zirconium tetrachlo-
ride (3.47 g, 14.9 mmol) to yield 8.05 g (11.8 mmol, 79%) of
compound 9c. Single crystals were obtained by slow evapora-
tion of the solvent of a solution in heptane. Mp: 173 °C. Anal.
Calcd for C34H52Cl2P2Zr (684.9): C, 59.63; H, 7.65. Found: C,
57.12; H, 7.36. 1H NMR (CD2Cl2, 599.11 MHz): δ 6.67 (m, 4H,
C5H4), 6.49 (m, 4H, C5H4), 1.84 (m, 12H, C6H11), 1.69 (m, 12H,
C6H11), 1.36-1.13 (m, 16H, C6H11), 0.97 (m, 4H, C6H11). 13C{1H}
NMR (CD2Cl2, 100.63 MHz): δ 124.4 (d, 1JPC ) 29.8 Hz, C-1),
124.1 (m, C5H4), 118.4 (m, C5H4), 34.1 (d, JPC ) 13.7 Hz, C6H11),
31.1 (d, JPC ) 12.1 Hz, C6H11), 30.7 (d, JPC ) 12.9 Hz, C6H11),
27.8 (d, JPC ) 10.5 Hz, C6H11), 27.6 (d, JPC ) 9.7 Hz, C6H11),
26.8 (d, JPC ) 1.6 Hz, C6H11). 31P{1H} NMR (CD2Cl2, 242.53
MHz): δ -3.0 (s, PCy2).
1
298 K): δ 54.6 (d, JRhP ) 150.6 Hz, P(i-Pr)2). IR (CH2Cl2):
νj(CO) 1959, 1913 cm-1
.
Preparation of Dicarbonyl[bis(η5-(dicyclohexylphos-
phino)cyclopentadienyl)methylzirconium-K2P,P′]rhod-
ium (Rh-Zr) (10c). Precooled (-30 °C) toluene was added
to a stirred mixture of 5c (32 mg, 50 µmol) and 6 (46 mg, 50
µmol) at room temperature. The solution was stirred for 5 min
at room temperature before CO was bubbled through it for 10
min. Immediately an orange precipitate appeared. The solid
was collected by filtration, washed once with toluene (1 mL)
and pentane (1 mL), and dried in vacuo to yield 31 mg of
compound 10c. Anal. Calcd for C37H55O2P2RhZr (787.9): C,
56.40; H, 7.04. Found: C, 56.76; H, 6.75. 1H NMR (d5-
bromobenzene, 599.11 MHz, 298 K): δ 6.44 (m, 2H, 2-H), 6.24
(m, 2H, 3-H), 5.15 (m, 2H, 4-H), 4.20 (m, 2H, 5-H), 2.62 (m,
X-ray Crystal Structure Analysis for 9c: formula C34H52-
Cl2P2Zr, Mr ) 684.82, light yellow crystal 0.20 × 0.15 × 0.10
mm, a ) 14.049(1) Å, b ) 21.756(1) Å, c ) 11.484(1) Å, â )

Metal-Metal-Bonded Early-Late Heterobimetallics
Organometallics, Vol. 24, No. 2, 2005 225
2H, 17-H), 2.56 (m, 2H, 13-H), 2.26-2.18 (m, 4H, 8-H, 12-H),
1.98 (m, 2H, 7-H), 1.85 (m, 4H, 14-H, 16-H), 1.81-1.68 (m,
12H, 9-H, 11-H, 13-H, 15-H, 17-H), 1.63 (m, 2H, 10-H), 1.47
(m, 2H, 8-H), 1.35 (m, 4H, 14-H, 16-H), 1.28-1.21 (m, 6H, 6-H,
7-H, 15-H), 1.14 (m, 4H, 9-H, 10-H), -0.76 (s, 3H, CH3).
13C{1H} NMR (d5-bromobenzene, 150.6 MHz, 298 K): δ 190.8
(CO, acquired from the 1H-13C ghmbc experiment), 115.5 (m,
C-3), 114.4 (m, C-2), 108.0 (m, C-4), 100.0 (m, C-5), 41.6 (m,
C-12), 40.9 (m, C-6), 31.6 (s, C-11, C-17), 31.5 (s, C-8), 30.4
P1h (No. 2), λ ) 0.710 73 Å, T ) 198 K, ω and æ scans, 12 918
reflections collected ((h, (k, (l), (sin θ)/λ ) 0.66 Å-1, 6555
independent (Rint ) 0.035) and 5902 observed reflections (I g
2σ(I)), 289 refined parameters, R1 ) 0.027, wR2 ) 0.065,
maximum (minimum) residual electron density 0.57 (-0.62)
e Å-3, hydrogen atoms calculated and refined as riding atoms.
Formation of (µ-Acetyl-1KO:2KC)[bis(η5-(dicyclohexyl-
phosphino)cyclopentadienyl)chlorozirconium-K2P,P′]-
chlororhodium (Rh-Zr) (12c). (a) Reaction of 5c with 6.
Dichloromethane (1.5 mL) was added to a stirred mixture of
5c (129 mg, 0.2 mmol) and 6 (184 mg, 0.2 mmol). Immediately
the solution turned dark red and gas evolution occurred. After
5 min. the orange solid was collected by filtration, washed
twice with precooled (-30 °C) dichloromethane and dried in
vacuo to yield 129 mg of an orange powder.
1
(m, C-13), 29.5 (m, C-7), 28.9 (s, JCH ) 117.0 Hz, CH3), 28.1
(m, C-9, C-14, C-16), 26.7 (s, C-15), 26.5 (s, C-10), n.o. (C-1).
31P{1H} NMR (d5-bromobenzene, 242.53 MHz, 298 K): δ 46.1
(d, JRhP ) 149.1 Hz, PPh2). IR (CH2Cl2): νj(CO) 1930, 1862
cm-1
.
X-ray Crystal Structure Analysis for 10c: formula
C44H63O2P2RhZr, Mr ) 880.01, red crystal 0.25 × 0.20 × 0.10
mm, a ) 33.117(1) Å, b ) 15.246(1) Å, c ) 21.888(1) Å, â )
130.74(1)°, V ) 8373.3(7) Å3, Fcalcd ) 1.396 g cm-3, µ ) 7.54
cm-1, empirical absorption correction (0.834 e T e 0.928), Z
) 8, monoclinic, space group C2/c (No. 15), λ ) 0.710 73 Å, T
) 198 K, ω and æ scans, 27 335 reflections collected ((h, (k,
(l), (sin θ)/λ ) 0.66 Å-1, 9924 independent (Rint ) 0.058) and
6656 observed reflections (I g 2σ(I)), 420 refined parameters,
R1 ) 0.050, wR2 ) 0.104, maximum (minimum) residual
electron density 1.20 (-0.66) e Å-3, hydrogen atoms calculated
and refined as riding atoms.
(b) Reaction of 7c with CH2Cl2. A solution of 7c in toluene
was prepared from 5c (32 mg, 50.0 µmol) and 6 (46 mg, 50
µmol) at -30 °C as described above. After 1 min dichlo-
romethane (3.2 µL, 50 µmol) was added to the crude mixture
and the color changed slowly to orange to form compound 12c.
(c) Reaction of 10b with CH2Cl2. A solution of 10c (8.0
mg, 9.1 µmol) in d2-dichloromethane (1 mL) was stirred for
1.5 h at room temperature. Subsequently the solvent was
removed in vacuo to yield 7.5 mg of compound 12c. Anal. Calcd
for C36H55Cl2OP2RhZr‚2CH2Cl2 (1000.7): C, 45.61; H, 5.94.
Found: C, 46.22; H, 6.89. 1H NMR (CD2Cl2, 599.11 MHz, 298
K): δ 6.47 (m, 2H, 3-H), 6.30 (br, 2H, 4-H), 5.91 (m, 2H, 5-H),
5.79 (m, 2H, 2-H), 3.54 (m, 2H, 6-H), 2.45 (s, 3H, CH3), 2.40
(m, 2H, Cy), 2.26 (m, 4H, Cy), 2.06 (m, 4H, Cy), 1.86-1.21 (m,
32H, Cy). 13C{1H} NMR (CD2Cl2, 150.6 MHz, 298 K): δ 289.0
Formation of (µ-Acetyl-1KO:2KC)[bis(η5-(diisopropyl-
phosphino)cyclopentadienyl)chlorozirconium-K2P,P′]-
chlororhodium (Rh-Zr) (12b). (a) Reaction of 5b with
6. Precooled (-30 °C) d2-dichloromethane (1 mL) was added
to a stirred mixture of 5b (22 mg, 45.4 µmol) and 6 (42 mg,
45.4 µmol). After 5 min at room temperature complete conver-
sion to compound 12b was observed by NMR spectroscopy. To
remove part of the triphenylphosphine, the solvent was
removed in vacuo. The crude product was washed once with
pentane (0.5 mL) and dried in vacuo to yield 34 mg of an
orange powder.
(b) Reaction of 7b with CH2Cl2. A solution of 7b in
toluene was prepared from 5b (24 mg, 50.1 µmol) and 6 (46
mg, 50 µmol) as described above. Dichloromethane (3.2 µL,
50 µmol) was added to the crude mixture, and the color
changed slowly to orange. After 1 h the orange solid was
collected by filtration, washed with toluene (0.5 mL), and dried
in vacuo to yield 42 mg of an orange solid (12b).
1
1
(dm, JRhC ) 23.3 Hz, CO), 125.6 (m, C-1), 121.1 (s, JCH
)
)
)
)
1
1
181 Hz, C-3), 113.2 (m, JCH ) 175 Hz, C-4), 110.7 (s, JCH
1
1
176 Hz, C-2), 105.3 (m, JCH ) 177 Hz, C-5), 39.0 (s, JCH
1
1
124 Hz, CH3), 37.8 (m, JCH ) 119 Hz, C-7), 35.0 (m, JCH
131 Hz, C-6), 31.8 (m, CyB), 30.8 (s, CyA), 30.7 (s, CyB), 30.4
(s, CyA), 28.6 (m, CyA), 28.0 (m, CyB), 27.9 (m, CyA + CyB),
27.0 (s, CyA), 26.7 (s, CyB). 31P{1H} NMR (CD2Cl2, 242.53 MHz,
298 K): δ 19.7 (d, 1JRhP ) 126.8 Hz, PCy2). IR (CH2Cl2): νj(CO)
1434 cm-1
.
X-ray Crystal Structure Analysis for 12c: formula
C36H55Cl2OP2RhZr‚C7H8, Mr ) 922.90, orange crystal 0.25 ×
0.20 × 0.05 mm, a ) 34.575(1) Å, b ) 10.989(1) Å, c ) 23.485-
(1) Å, â ) 109.66(1)°, V ) 8402.8(9) Å3, Fcalcd ) 1.459 g cm-3
,
µ ) 8.76 cm-1, empirical absorption correction (0.811 e T e
0.958), Z ) 8, monoclinic, space group P21/c (No. 14), λ )
0.710 73 Å, T ) 198 K, ω and æ scans, 47 132 reflections
collected ((h, (k, (l), (sin θ)/λ ) 0.66 Å-1, 19 583 independent
(Rint ) 0.051) and 14 192 observed reflections (I g 2σ(I)), 905
refined parameters, R1 ) 0.040, wR2 ) 0.078, maximum
(c) Reaction of 10b with CH2Cl2. A solution of 10b (32
mg, 50 µmol) in dichloromethane (2 mL) was stirred for 16 h
at room temperature. Subsequently the solvent was removed
in vacuo to yield 30 mg of compound 12b. Anal. Calcd for
C24H39Cl2OP2RhZr (670.5): C, 42.99; H, 5.86. Found: C, 42.92;
H, 6.14. 1H NMR (CD2Cl2, 599.11 MHz, 298 K): δ 6.49 (m,
2H, 3-H), 6.34 (m, 2H, 4-H), 6.00 (m, 2H, 5-H), 5.90 (m, 2H,
2-H), 3.77 (m, 2H, 6-H), 2.47 (m, 3H, CH3), 1.82 (m, 2H, 9-H),
1.53 (m, 6H, 7-H), 1.50 (m, 6H, 10-H), 1.35 (m, 6H, 11-H), 1.32
(m, 6H, 8-H). 13C{1H} NMR (CD2Cl2, 150.6 MHz, 298 K): δ
290.3 (dt, 1JRhC ) 30.6 Hz, 2JPC ) 8.1 Hz, CO), 126.8 (m, C-1),
120.6 (m, C-3), 113.6 (m, C-4), 111.1 (m, C-2), 105.9 (m, C-5),
(minimum) residual electron density 0.60 (-0.67) e Å-3
,
hydrogen atoms calculated and refined as riding atoms, two
almost identical molecules in the asymmetric unit.
Acknowledgment. Generous financial support from
the Deutsche Forschungsgemeinschaft and the Fonds
der Chemischen Industrie is gratefully acknowledged.
We cordially thank Prof. C. Elsevier and co-workers for
helping us with some NMR experiments.
1
40.4 (m, JCH ) 127.4 Hz, CH3), 27.5 (m, C-9), 25.3 (m, C-6),
21.5 (m, C-10), 19.9 (m, C-7 + C-8), 19.5 (m, C-11). 31P{1H}
1
NMR (CD2Cl2, 242.53 MHz, 298 K): δ 27.5 (d, JRhP ) 127.6
Hz, P(i-Pr)2). IR (CH2Cl2): νj(CO) 1434 cm-1
.
Supporting Information Available: CIF files giving
details of the X-ray crystal structure analysis (5b,c, 7a, 9a-
d, 10c, and 12b,c) and text giving additional spectroscopic
data. This material is available free of charge via the Internet
at http://pubs.acs.org.
X-ray Crystal Structure Analysis for 12b: formula
C24H39Cl2OP2RhZr, Mr ) 670.52, orange crystal 0.15 × 0.15 ×
0.05 mm, a ) 9.290(1) Å, b ) 11.545(1) Å, c ) 14.362(2) Å, R
) 98.4(1)°, â ) 97.70(1)°, γ ) 112.41(1)°, V ) 1380.2(2) Å3,
Fcalcd ) 1.613 g cm-3, µ ) 13.00 cm-1, empirical absorption
correction (0.829 e T e 0.938), Z ) 2, triclinic, space group
OM049346Z