Carbene iridium(I) and iridium(III) complexes containing the metal center in different stereochemical environments

Article abstract of DOI:10.1021/om020069a

The mixed-ligand complex [IrCl(C₂H₄)(SbiPr₃)(PiPr₃)] (2), prepared from [IrCl(C₂H₄)-(PiPr₃)]₂ (1) and SbiPr₃, reacts not only with CO, diphenylacetylene, an

Full text of DOI:10.1021/om020069a

Organometallics 2002, 21, 2369-2381
2369
Ca r ben e Ir id iu m (I) a n d Ir id iu m (III) Com p lexes
Con ta in in g th e Meta l Cen ter in Differ en t Ster eoch em ica l
En vir on m en ts†
Dagmara A. Ortmann, Birgit Weberndo¨rfer, Kerstin Ilg,
Matthias Laubender, and Helmut Werner*
Institut fu¨r Anorganische Chemie, Universita¨t Wu¨rzburg, Am Hubland,
D-97074 Wu¨rzburg, Germany
Received J anuary 30, 2002
The mixed-ligand complex [IrCl(C2H4)(SbiPr3)(PiPr3)] (2), prepared from [IrCl(C2H4)-
(PiPr3)]2 (1) and SbiPr3, reacts not only with CO, diphenylacetylene, and H2 by ligand
substitution or oxidative addition but also with diaryldiazomethanes R2CN2 to give the four-
coordinate iridium(I) carbenes [IrCl(dCR2)(SbiPr3)(PiPr3)] (8-10) in 60-70% isolated yield.
In contrast, treatment of 2 and of the related cyclooctene derivative trans-[IrCl(C8H14)-
(SbiPr3)2] (12) with C5Cl4N2 affords the diazoalkane complexes trans-[IrCl(N2C5Cl4)(SbiPr3)-
(EiPr3)] (11, E ) P; 13, E ) Sb) without elimination of N2. Displacement of the stibine ligand
in 8-10 by PiPr3 leads to the corresponding bis(phosphine) compounds trans-[IrCl(dCR2)-
(PiPr3)2] (14-16), while the reaction of 8 (R ) C6H5) with NaC5H5 yields the half-sandwich-
type complex [(η5-C5H5)Ir(dCPh2)(PiPr3)] (17). Protonation of 17 with HCl occurs stepwise
to give via the iridium(III) alkyl [(η5-C5H5)IrCl(CHPh2)(PiPr3)] (20) the ring-substituted
isomer [(η5-C5H4CHPh2)IrHCl(PiPr3)] (21); however, if 17 is treated with HBF4, a cationic
complex is formed which probably contains a η3-coordinated benzylic ligand. The square-
planar iridium(I) carbenes 8 and 14 react with HBX4 (X ) F, ArF) to afford the ionic products
[IrHCl(dCPh2)(PiPr3)(EiPr3)]BX4 (23, 24, E ) P; 25, E ) Sb) and with HCl to give the
relatively labile octahedral species [IrHCl2(dCPh2)(PiPr3)(EiPr3)] (26, E ) P; 27, E ) Sb).
Treatment of 8 and 14 with ethene yields, besides [IrCl(C2H4)2(SbiPr3)2] (18) and/or trans-
[IrCl(C2H4)(PiPr3)2] (28), a mixture of two isomeric olefinic products CH2dCHCHPh2 (29)
and CH3CHdCPh2 (30), the ratio of which is independent of the ligand sphere of the iridium
precursor. The molecular structures of 13, 14, 17, and 24 have been determined by X-ray
crystallography.
In tr od u ction
order to find out how similar or how different their
reactivity is compared with the rhodium(I) counterparts.
However, attempts to obtain the four-coordinate com-
pound trans-[IrCl(C2H4)(SbiPr3)2], anticipated to be the
best starting material, from [IrCl(C2H4)2]2 and excess
SbiPr3 led instead to the formation of the five-coordinate
species [IrCl(C2H4)2(SbiPr3)2], which did not react
with diazoalkanes R′RCN2 to give trans-[IrCl(dCRR′)-
(SbiPr3)2].4
Therefore, we set out to develop another synthetic
route to iridium(I) carbenes and found, quite unexpect-
edly, that the mixed phosphine/stibine complex [IrCl-
(C2H4)(SbiPr3)(PiPr3)] is a suitable precursor to prepare
the target molecules. Here we describe the preparation
of square-planar, octahedral, and half-sandwich-type
iridium complexes containing IrdC(aryl)2 as a molecular
unit and discuss in particular their behavior toward
Bro¨nsted acids. Some of these results have already been
communicated.5
In the context of our studies on the chemistry of
square-planar complexes of the general composition
trans-[RhCl{dC(dC)nRR′}(PiPr3)2] (n ) 1, 2, and 4),1
we recently reported also a convenient synthetic route
to structurally related rhodium carbenes trans-[RhCl-
(dCRR′)(PiPr3)2].2 The key to success was to use instead
of trans-[RhCl(C2H4)(PiPr3)2] the more reactive bis(triiso-
propylstibine) derivative trans-[RhCl(C2H4)(SbiPr3)2] as
the precursor and, after it had been reacted with
R′RCN2 to give trans-[RhCl(dCRR′)(SbiPr3)2], to sub-
sequently replace the stibine ligands with triisopropyl-
phosphine. Since both trans-[RhCl(dCRR′)(SbiPr3)2] and
trans-[RhCl(dCRR′)(PiPr3)2] provide a rich chemistry
including novel C-C coupling reactions,2,3 we became
interested in preparing the corresponding iridium(I)
complexes trans-[IrCl(dCRR′)(EiPr3)2] (E ) Sb, P) in
† Dedicated to Professor Waldemar Adam on the occasion of his
65th birthday.
(1) (a) n ) 1: Werner, H.; Garcia Alonso, F. G.; Otto, H.; Wolf, J . Z.
Naturforsch., B 1988, 43, 722-726. (b) n ) 2: Werner, H.; Rappert,
T.; Wiedemann, R.; Wolf, J .; Mahr, N. Organometallics 1994, 13, 2721-
2727. (c) n ) 4: Kovacik, I.; Laubender, M.; Werner, H. Organome-
tallics 1997, 16, 5607-5609.
(2) Schwab, P.; Mahr, N.; Wolf, J .; Werner, H. Angew. Chem. 1993,
105, 1498-1500; Angew. Chem., Int. Ed. Engl. 1993, 32, 1480-1482.
(3) (a) Werner, H. J . Organomet. Chem. 1995, 500, 331-336. (b)
Werner, H.; Schwab, P.; Bleuel, E.; Mahr, N.; Steinert, P.; Wolf, J .
Chem. Eur. J . 1997, 3, 1375-1384. (c) Bleuel, E. Dissertation,
Universita¨t Wu¨rzburg, 2000.
(4) Werner, H.; Ortmann, D. A.; Gevert, O. Chem. Ber. 1996, 129,
411-417.
10.1021/om020069a CCC: $22.00 © 2002 American Chemical Society
Publication on Web 05/14/2002

2370 Organometallics, Vol. 21, No. 12, 2002
Ortmann et al.
Sch em e 1
Sch em e 2
Resu lts a n d Discu ssion
1. P r ep a r a tion , Su bstitu tion , a n d Hyd r ogen a -
tion Rea ction s of [Ir Cl(C2H4)(SbiP r 3)(P iP r 3)]. In
contrast to [IrCl(C8H14)(PiPr3)]2,6 which upon treatment
with SbiPr3 affords a mixture of products, the related
ethene-containing dimer 1 reacts with 2 equiv of triiso-
propylstibine in pentane at room temperature to give
the monomeric 16-electron complex 2 in nearly quan-
titative yield (Scheme 1). The bright orange solid, which
can be handled in air for a short period of time and
stored under argon at -30 °C for weeks, is relatively
unstable in solution and decomposes particularly in
dichloromethane quite rapidly. The 13C NMR spectrum
of 2 displays not only a doublet at δ 20.2 for the
PCHCH3 but also one at δ 17.5 for the SbCHCH3 carbon
atoms, the latter having a smaller 13C-31P coupling
constant of 6.1 Hz.
Passing a slow stream of CO through a solution of 2
in pentane for only ca. 10 s leads to the replacement of
the olefinic ligand and the generation of the monocar-
bonyl derivative 3, isolated in 80% yield. The IR
spectrum of the lemon-yellow, moderately air-sensitive
solid shows a strong ν(CO) stretching mode at 1926
cm-1, which is only slightly red-shifted compared with
the bis(phosphine) analogue trans-[IrCl(CO)(PiPr3)2].7
If treatment of 2 with CO is continued for ca. 1 min,
two new compounds are formed, which have been
identified by IR and NMR spectroscopy as [IrCl(CO)2-
(SbiPr3)2] and trans-[IrCl(CO)(PiPr3)2].7,8 We assume
that in the course of this reaction a short-lived mixed
stibine/phosphine intermediate [IrCl(CO)2(SbiPr3)(PiPr3)]
is generated, which conproportionates to give the ther-
modynamically more stable Ir(SbiPr3)2 and Ir(PiPr3)2
products.
pounds [IrCl(C2H4)2(SbiPr3)2] and trans-[IrCl(C2H4)-
(PiPr3)2], respectively.
The olefinic ligand of 2 can be displaced not only by
CO but also by diphenylacetylene and H2 (Scheme 2).
Treatment of 2 with C2Ph2 in pentane affords the substi-
tution product 5, which is the link between the bis-
(stibine) and bis(phosphine) analogues trans-[IrCl(C2-
Ph2)(SbiPr3)2]4 and trans-[IrCl(C2Ph2)(PiPr3)2].6 The
hydrogenation of 2 at room temperature leads to the
formation of a dihydridoiridium(III) species which is iso-
lated as a mixture of two isomers 7a and 7b. If the reac-
tion of 2 with H2 is carried out at -40 °C in pentane,
an oxidative addition occurs to give the octahedral com-
plex 6 as a pale yellow solid in 84% yield. Typical spec-
1
troscopic features of 6 are the two high-field H NMR
resonances for the cis-disposed hydrides at δ -10.89 and
-28.24 and the two sets of signals for the protons and
carbon atoms of the diastereotopic CH3 groups of the
SbiPr3 and PiPr3 ligands in the 1H and 13C NMR
spectra. The IR spectrum of 6 displays two bands for
the Ir-H stretching modes at 2201 and 2093 cm-1, the
positions being nearly identical to those of the related
bis(arsine) complex cis,trans-[IrH2Cl(C2H4)(AsiPr3)2].9
While in the absence of a dihydrogen atmosphere
compound 6 is stable and can be stored under argon for
days, in the presence of H2 it smoothly reacts at room
temperature to give 7a /7b and ethane. After removal
of the solvent and recrystallization from acetone at -78
°C a yellow microcrystalline solid was isolated which
1
partly converts to a yellow oil at ca. 20 °C. The H and
31P NMR spectra, both taken immediately after the
yellow solid is dissolved in C6D6, confirm the presence
of two isomers 7a and 7b, the ratio of which increases
from ca. 4:1 to 1:3 upon storing the solution for 3 days.
The four-coordinate compound 2 also reacts with C2H4
to give the bis(ethene) complex 4 (see Scheme 1). In
contrast to [IrCl(C2H4)2(SbiPr3)2],4 the stibine/phosphine
derivative 4 is rather labile, and after removing the
ethene atmosphere, the starting material 2 is regener-
ated. The 31P NMR spectrum of 4 shows a singlet
resonance at δ -3.4, which appears at significantly
higher field compared with 2 (δ 15.5). In C6D6 solution,
a slow rearrangement of 4 takes place, which finally
leads to the formation of the more symmetrical com-
1
Since the H NMR spectrum of the initially dominating
isomer 7a shows only one doublet in the high-field
region at δ -25.31, we assume that in 7a the hydrido
ligands are stereochemically equivalent and occupy two
basal positions of a trigonal bipyramid. The spectrum
of the thermodynamically favored isomer 7b exhibits
two doublet-of-doublet resonances at δ -15.93 and
-26.47, thus illustrating the inequivalence of the Ir-H
units. Moreover, the similar values of the 1H-31P
coupling constants (15.2 and 13.7 Hz) indicate that in
7b both hydrides are cis-disposed to the triisopropyl-
phosphine ligand. We note that even after storing the
(5) Ortmann, D. A.; Weberndo¨rfer, B.; Scho¨neboom, J .; Werner, H.
Organometallics 1999, 18, 952-954.
(6) Dziallas, M.; Ho¨hn, A.; Werner, H. J . Organomet. Chem. 1987,
330, 207-219.
(7) (a) Strohmeier, W.; Onoda, T. Z. Naturforsch., B 1968, 23, 1377-
1379. (b) Werner, H.; Ho¨hn, A. Z. Naturforsch., B 1984, 39, 1505-
1509.
(8) Ortmann, D. A.; Gevert, O.; Laubender, M.; Werner, H. Orga-
nometallics 2001, 20, 1776-1782.
(9) Werner, H.; Ortmann, D. A.; Ilg, K. Z. Anorg. Allg. Chem. 2000,
626, 2457-2462.

Carbene Ir(I) and Ir(III) Complexes
Organometallics, Vol. 21, No. 12, 2002 2371
Sch em e 3
room temperature affords the diarylcarbene complexes
8-10 in 60-70% isolated yield. The iridium carbenes
8-10 are more air-sensitive and thermally less stable
than the bis(stibine)rhodium analogues trans-
[RhCl(dCR2)(SbiPr3)2].2,3 However, under argon at -30
°C they can be stored without decomposition for weeks.
The most characteristic spectroscopic feature of 8-10
is the signal for the carbene carbon atom at, respec-
tively, δ 240.9 (8), 244.7 (9), and 235.7 (10) in the 13C
NMR spectra, which in each case is split into a doublet
due to 13C-31P coupling. With regard to the preparative
procedure for 8-10 it should be mentioned that the
starting materials 2 and R2CN2 have to be used in a
1:1 molar ratio since with excess diazoalkane a subse-
quent reaction of the iridium carbene occurs, leading
to a mixture of products which could not be exactly
identified.
The ethene-containing precursor 2 also reacts with
C5Cl4N2, but in this case no evolution of N2 can be
observed. From a pentane solution a green solid pre-
cipitates, which after recrystallization from acetone
correctly analyzes as [IrCl(N2C5Cl4)(SbiPr3)(PiPr3)] (11).
In contrast to the iridium carbenes 8-10, the diazoal-
kane derivative 11 is only slightly air-sensitive and less
soluble in ether and hexane. The cyclooctene complex
12 behaves similarly to 2 and upon treatment with C5-
Cl4N2 gives the bis(stibine) counterpart of 11 with an
analytical composition corresponding to 13 (see Scheme
3). According to the spectroscopic data of 11 and 13, we
assume that the diazoalkane ligand is end-on bonded
via the terminal nitrogen atom to the metal center.
Diagnostic for this type of coordination12 is an N-N
stretching vibration in the IR spectra at 1830-1840
cm-1 as well as a signal in the 13C NMR spectra at δ
63.8 (11) and 61.0 (13) for the N2C carbon atom.
Attempts to eliminate N2 from 11 or 13 and to transform
these compounds to the corresponding carbene com-
plexes [IrCl(dCC4Cl4)(SbiPr3)(EiPr3)] (E ) P, Sb) re-
mained unsuccessful.
F igu r e 1. Molecular diagram of compound 13. Selected
bond distances (Å) and angles (deg): Ir-Cl1 2.275(4), Ir-
Sb1 2.599(1), Ir-Sb2 2.598(1), Ir-N1 1.79(1), N1-N2
1.18(1), N2-C1 1.36(1); N1-Ir-Cl1 178.7(4), Sb1-Ir-Sb2
174.96(4), Cl1-Ir-Sb1 88.5(1), Cl1-Ir-Sb2 86.6(1), N1-
Ir-Sb1 91.2(3), N1-Ir-Sb2 93.8(4), Ir-N1-N2 172(1),
N1-N2-C1 136(1).
solution of 7a /7b in C6D6 under a H2 atmosphere for
one week, no conversion to [IrH2Cl(PiPr3)2]10 and [IrH2-
Cl(SbiPr3)2]4 takes place.
2. P r ep a r a t ion a n d Molecu la r St r u ct u r e of
Squ a r e-P la n a r a n d Ha lf-Sa n d w ich -Typ e Ir id iu m -
(I) Ca r ben es. In contrast to trans-[IrCl(C2H4)(PiPr3)2],
which does not cleanly react with Ph2CN2 to give trans-
[IrCl(dCPh2)(PiPr3)2],11 treatment of the mixed-ligand
compound 2 with diphenyldiazomethane as well as with
(p-C6H4Me)2CN2 and (p-C6H4Cl)2CN2 in benzene at
(10) (a) Hietkamp, S.; Stufkens, D. J .; Vrieze, K. J . Organomet.
Chem. 1977, 139, 347-356. (b) Werner, H.; Wolf, J .; Ho¨hn, A. J .
Organomet. Chem. 1985, 287, 395-407. (c) Garlaschelli, L.; Khan, S.
I.; Bau, R.; Longoni, G.; Koetzle, T. F. J . Am. Chem. Soc. 1985, 107,
7212-7213.
(11) Brandt, L.; Wolf, J .; Werner, H. J . Organomet. Chem. 1993,
444, 235-244.
(12) Dartiguenave, M.; Menu, M. J .; Deydier, E.; Dartiguenave, Y.;
Siebald, H. Coord. Chem. Rev. 1998, 178, 623-663.

2372 Organometallics, Vol. 21, No. 12, 2002
Ortmann et al.
Sch em e 4
The result of the X-ray crystal structure analysis of
13 is shown in Figure 1. The coordination sphere around
iridium is square-planar with trans-disposed stibine
ligands and an almost linear Cl-Ir-N1 axis. The N2C5-
Cl4 moiety possesses the “singly bent” geometry, as has
also been found for trans-[IrCl(N2C5Cl4)(PPh3)2].13 The
nitrogen, carbon, and chlorine atoms of the coordinated
N2C5Cl4 molecule lie in one plane which is not exactly
perpendicular to the plane containing Ir, Cl, Sb1, and
Sb2. The dihedral angle between the two planes is
77.1(5)°. The distance N1-N2 of 1.18(1) Å is halfway
between that of an N-N triple bond (1.098 Å in N2)14
and an N-N double bond (1.244 Å in PhNdNPh),15
being in agreement with the assumption that N2C5Cl4
is a moderate π-acceptor ligand. The result that the Ir-
Sb distances of 13 (2.599(1) and 2.598(1) Å) are nearly
identical to those of [IrHCl(η3-C3H5)(SbiPr3)2] (2.5642(5)
and 2.5569(7) Å)8 is noteworthy insofar as in the π-allyl-
(hydrido) complex the metal is in the oxidation state
+III.
F igu r e 2. Molecular diagram of compound 14. Selected
bond distances (Å) and angles (deg): Ir-P1 2.344(1),
Ir-P2 2.374(1), Ir-Cl 2.434(2), Ir-C1 1.887(5), C1-C2
1.487(7), C1-C8 1.509(7); P1-Ir-P2 162.21(5), P1-Ir-Cl
86.18(6), P1-Ir-C1 96.0(2), P2-Ir-Cl 86.28(6), P2-Ir-
C1 95.0(2), Ir-C1-C2 128.9(4), Ir-C1-C8 117.7(3), C2-
C1-C8 113.4(4).
In analogy with the rhodium carbenes trans-[RhCl-
(dCRR′)(SbiPr3)2],2,3 the Ir-SbiPr3 bond in the iridium
compounds 8-10 is also readily dissociable. Therefore,
treatment of a solution of 8-10 in pentane or benzene
at room temperature with an equimolar amount of PiPr3
affords the bis(phosphine) complexes 14-16 in good
yields (Scheme 4). While 14 and 15 could be isolated,
after recrystallization from acetone, as analytically pure
brown solids, 16 is much less stable and smoothly
decomposes in solution (in toluene even at -20 °C). It
has thus been characterized only by spectroscopic
techniques. The resonance for the carbene carbon atom
appears in the 13C NMR spectra of 14-16 at, respec-
tively, δ 234.7 (14), 245.5 (15), and 237.8 (16) and is
split into a triplet due to coupling with two 31P nuclei.
The X-ray crystal structure analysis of 14 confirmed
the proposed coordination geometry of the molecule
(Figure 2). Both the P1-Ir-P2 and Cl-Ir-C1 axes are
somewhat bent, the two bond angles (162.21(5)° and
166.7(2)°) being quite similar to those of the rhodium
counterpart trans-[RhCl(dCPh2)(PiPr3)2] (161.55(3)° and
166.24(9)°).3b The repulsive forces between the isopropyl
and phenyl groups of the PiPr3 and CPh2 ligands are
probably responsible for this bending. We assume that
steric effects also explain why the dihedral angle
between the planes [Ir,Cl,P1,P2] and [C1,C2,C8] is not
0° (as suggested by bonding arguments)18 but is 67.3(3)°
1
The H NMR spectra of 14-16 display for the PCHCH3
protons a doublet of virtual triplets which is typical for
square-planar iridium(I) compounds with the two PiPr3
ligands in trans disposition.6,16 With regard to the
lability of 16 we note that attempts to prepare stable
rhodium carbenes with RhdC(p-C6H4Cl)2 as a molecular
unit remained unsuccessful.17
(16) (a) Werner, H.; Ho¨hn, A. J . Organomet. Chem. 1984, 272, 105-
113. (b) Ho¨hn, A.; Werner, H. J . Organomet. Chem. 1990, 382, 255-
272. (c) Werner, H.; Ho¨hn, A.; Schulz, M. J . Chem. Soc., Dalton Trans.
1991, 777-781. (d) Wolf, J .; Lass, R. W.; Manger, M.; Werner, H.
Organometallics 1995, 14, 2649-2651. (e) Lass, R. W.; Steinert, P.;
Wolf, J .; Werner, H. Chem. Eur. J . 1996, 2, 19-23. (f) Werner, H.;
Lass, R. W.; Gevert, O.; Wolf, J . Organometallics 1997, 16, 4077-4088.
(g) Werner, H.; Ilg, K.; Weberndo¨rfer, B. Organometallics 2000, 19,
3145-3153.
(17) Schwab, P. Dissertation, Universita¨t Wu¨rzburg, 1994.
(18) Hofmann, P. In Transition Metal Carbene Complexes; Do¨tz, K.
H., Fischer, H., Hofmann, P., Kreissl, F. R., Schubert, U., Weiss, K.,
Eds.; Verlag Chemie: Weinheim, 1983; p 113.
(13) (a) Schramm, K. D.; Ibers, J . A. Inorg. Chem. 1980, 19, 1231-
1236. (b) Schramm, K. D.; Ibers, J . A. Inorg. Chem. 1980, 19, 2435-
2440.
(14) Huheey, J . E. Anorganische Chemie, Prinzipien von Struktur
und Reaktivita¨t, 1st ed.; Verlag Walter de Gruyter: Berlin-New York,
1988; p 115.
(15) Brown, C. J . Acta Crystallogr. 1966, 21, 153-158.

Carbene Ir(I) and Ir(III) Complexes
Organometallics, Vol. 21, No. 12, 2002 2373
Sch em e 5
and thus deviates significantly from the expected value.
The Ir-C1 bond length (1.887(5) Å) is longer than in
the vinylidene and butatrienylidene iridium analogues,
trans-[IrCl(dCdCHCO2Me)(PiPr3)2] (1.764(6) Å)16b and
trans-[IrCl(dCdCdCdCPh2)(PiPr3)2] (1.816(6) Å),19 and
is almost the same as in the methylene complex
[Ir(dCH2){κ3-N(SiMe2CH2PPh2)2}] (1.868(9) Å).20
The reactivity of the structurally related molecules 8
and 14 toward NaC5H5 is quite different. While the bis-
(phosphine) derivative 14 is completely inert toward
sodium cyclopentadienide (THF, room temperature), the
mixed-ligand compound 8 reacts under the same condi-
tions with NaC5H5 to give, after recrystallization from
pentane at -78 °C, the half-sandwich-type complex 17
in 70% yield. We note that in one case, when we used a
larger amount of the starting material 8 (ca. 0.5 mmol),
instead of a dark violet solid an oily substance was
isolated which contained besides 17 as the byproduct
some free SbiPr3. It could be separated from 17 via
F igu r e 3. Molecular diagram of compound 17. Selected
bond distances (Å) and angles (deg): Ir-P 2.262(2), Ir-
C1 1.904(5), Ir-C14 2.308(7), Ir-C15 2.266(7), Ir-C16
2.210(7), Ir-C17 2.239(7), Ir-C18 2.316(6), C1-C2 1.499(7),
C1-C8 1.492(7); P-Ir-C1 99.9(2), Ir-C1-C2 116.2(4),
C2-C1-C8 109.2(4).
1
conversion (with CH3I) to [CH3SbiPr3]I. The H NMR
spectrum of 17 displays a doublet for the C5H5 protons
at δ 4.92 and the 13C NMR spectrum a doublet for the
carbene carbon atom at δ 217.2. The most remarkable
spectroscopic feature, however, is the appearance of two
sets of signals for the carbon atoms of the phenyl rings
indicating that the rotation around the IrdC bond is
considerably hindered. A similar observation was re-
ported by Klein and Bergman for the analogous meth-
ylene compound [(η5-C5Me5)Ir(dCH2)(PMe3)].21 It is
worth mentioning that in contrast to this IrdCH2
species (generated upon photolysis of the metallacycle
[(η5-C5Me5)Ir(κ-C,O-CH2CMe2O)(PMe3)] at -60 °C) the
diphenylcarbene complex 17 is thermally quite stable
and decomposes only at temperatures above 93 °C.
The result of the X-ray crystal structure analysis
of 17 is shown in Figure 3. The iridium has a some-
what distorted trigonal coordination sphere if the
midpoint of the cyclopentadienyl ring is taken as one
coordination site. The Ir-C1 bond length (1.904(5) Å)
is practically identical to that in the related rhodium
carbene [(η5-C5H5)Rh(dCPh2)(CO)] (1.906(3) Å).22 The
Ir-Ccyclopentadienyl distances lie between 2.210(7) and
2.316(6) Å, reflecting the different binding properties
of the PiPr3 and CPh2 groups. We note that, to the best
of our knowledge, compound 17 is the first structurally
characterized iridium complex of the general composi-
tion [(η5-C5H5)Ir(L)(PR3)], where L is a carbene, vinyl-
idene, or allenylidene ligand.23
5 failed. Treatment of 184 with NaC5H5 in THF affords
the expected half-sandwich-type compound 19, which,
however, does not react even with an excess of Ph2CN2
1
by ligand exchange. The H and 13C NMR spectroscopic
data of 19 are rather similar to those of the correspond-
ing rhodium complex [(η5-C5H5)Rh(C2H4)(SbiPr3)]22 and
deserve no further comment.
3. R ea ct ion s of t h e Ir id iu m Ca r b en es w it h
Br o1n sted Acid s. While investigating the reactivity of
diphenylcarbenerhodium(I) compounds of the general
composition [(η5-L)Rh(dCPh2)(SbiPr3)] and [(η5-L)Rh-
(dCPh2)(PR3)] (L ) C5H5, C5H4SiMe3, C9H7),22,24 we
recently observed that upon treatment of [(η5-C5H5)Rh-
(dCPh2)(PiPr3)] with HCl or CF3CO2H a migratory
insertion of the CPh2 moiety into one of the C-H bonds
of the cyclopentadienyl ring occurs.25 From a labeling
study we concluded that initially, via addition of the
Bro¨nsted acid to the rhodium-carbene bond, a labile
intermediate [(η5-C5H5)RhX(CHPh2)(PiPr3)] is formed,
which quickly rearranges to the isomeric ring-substi-
tuted derivative [(η5-C5H4CHPh2)RhHX(PiPr3)].
The supposed M(CHPh2) species could be isolated for
M ) Ir. Treatment of a solution of 17 in pentane with
(23) (a) Fischer, H. In Transition Metal Carbene Complexes; Do¨tz,
K. H., Fischer, H., Hofmann, P., Kreissl, F. R., Schubert, U., Weiss,
K., Eds.; Verlag Chemie: Weinheim, 1983; p 1. (b) Bruce, M. I. Chem.
Rev. 1991, 91, 197-257. (c) Bruce, M. I. Chem. Rev. 1998, 98, 2797-
2858.
(24) (a) Bleuel, E.; Werner, H. C. R. Acad. Sci. Paris, Ser. IIc 1999,
341-349. (b) Bleuel, E.; Gevert, O.; Laubender, M.; Werner, H.
Organometallics 2000, 19, 3109-3114.
(25) (a) Herber, U.; Bleuel, E.; Gevert, O.; Laubender, M.; Werner,
H. Organometallics 1998, 17, 10-12. (b) Bleuel, E.; Schwab, P.;
Laubender, M.; Werner, H. J . Chem. Soc., Dalton Trans. 2001, 266-
273.
Attempts to prepare the stibine analogue of 17
following the sequence of reactions outlined in Scheme
(19) Ilg, K.; Werner, H. Angew. Chem. 2000, 112, 1691-1693;
Angew. Chem., Int. Ed. 2000, 39, 1632-1634.
(20) Fryzuk, M. D.; Huang, L.; McManus, N. T.; Paglia, P.; Rettig,
S. J .; White, G. S. Organometallics 1992, 11, 2790-2795.
(21) Klein, D. P.; Bergman, R. G. J . Am. Chem. Soc. 1989, 111,
3079-3080.
(22) Werner, H.; Schwab, P.; Bleuel, E.; Mahr, N.; Windmu¨ller, B.;
Wolf, J . Chem. Eur. J . 2000, 6, 4461-4470.

2374 Organometallics, Vol. 21, No. 12, 2002
Ortmann et al.
Sch em e 6
Sch em e 7
gaseous HCl results in a rapid change of color from
violet to orange-yellow and affords the slightly air-
sensitive alkyliridium(III) complex 20 in virtually quan-
titative yield (Scheme 6). Diagnostic for the metal-
bonded CHPh2 unit is a resonance in the 1H NMR
spectrum at δ 5.75 for the CH proton and a signal in
the 13C NMR spectrum at δ 24.6 for the substituted
methyl carbon atom. Due to 1H-31P and 13C-31P
couplings, these signals are split into doublets. Since
20 contains a chiral center, the CH3 groups of the
phosphine are diasterotopic and thus give rise to two
resonances (as doublets of doublets) in the 1H NMR
spectrum.
the ionic character of the compound. The 1H NMR
spectrum of 22 displays the resonance for the CHPh2
proton at δ 3.32 and thus at higher field (ca. 2.3 ppm)
1
compared to 20. Since in the H and 13C NMR spectra
of 22 the signals for the C6H5 protons and the phenyl
carbon atoms are relatively broad, we assume that the
diphenylmethyl ligand is coordinated as a substituted
η3-benzyl group and exhibits, at room temperature, a
fluxional behavior similarly to that of the structurally
related ruthenium compound [(η5-C5H5)Ru(η3-CHPh2)-
(PPh3)].27,28 Attempts to slow the fluctional process and
confirm the η3-coordination of the CHPh2 moiety by
spectroscopic means failed because the BF4 salt 22
precipitates even in CD2Cl2 below 0 °C.
Warming a solution of 20 in benzene for 2 min to
reflux temperature leads to a stepwise change of color
from orange-yellow to red and after ca. 10 s from red to
yellow. After removal of the solvent and recrystallization
from CH2Cl2/hexane the chloro(hydrido) complex 21 is
isolated as a yellow solid in 95% yield. We assume that
in the initial step of the isomerization a migration of
the CHPh2 unit from the metal to the five-membered
ring takes place to give the cyclopentadieneiridium(I)
intermediate [(η4-C5H5CHPh2)IrCl(PiPr3)]. Subsequently,
this intermediate could rearrange via an exo-H migra-
tion on the upper face of the ring to generate an isomer
with both an exo and an endo hydrogen, and final
migration of the endo-H from the ring to iridium would
lead to 21. Following the conversion of 20 to 21 in C6D6
by 1H NMR spectroscopy, the formation of a new species
can be observed for which the appearance of two
Like the half-sandwich-type complex 17, the square-
planar iridium(I) compounds 8 and 14 also react smoothly
29
with HBF4 or Brookhart’s acid HB(ArF)4 to afford the
cationic carbene(hydrido)iridium(III) derivatives 23-25
in 83-95% yield (Scheme 7). The red (or red-pink) solids
are thermally quite stable, are soluble in acetone and
dichloromethane, and can be stored under argon at room
temperature for days. While it is conceivable that in
solution (acetone or CH2Cl2) 1:1 adducts with a solvent
molecule are generated, the elemental analyses of 23-
1
doublets at δ 3.42 and 3.19 (with a H-1H coupling of
ca. 10 Hz) is characteristic. In agreement with previous
findings,25 we assign these signals to the ring-CH
protons of the cyclopentadiene ligand. In this context
we note that related rhodium compounds of the general
composition [(η4-diene)RhX(PR3)], being formally iso-
electronic to the supposed intermediate [(η4-C5H5CHPh2)-
IrCl(PiPr3)], exist and in one case (for X ) triflate and
PR3 ) PiPr3) have been characterized by X-ray crystal-
lography.26
(27) (a) Braun, T.; Gevert, O.; Werner, H. J . Am. Chem. Soc. 1995,
117, 7291-7292. (b) Braun, T. Dissertation, Universita¨t Wu¨rzburg,
1996.
(28) For pertinent papers on the dynamic behavior of η3-benzyl
complexes see: (a) Stu¨hler, H. O. Angew. Chem. 1980, 92, 475-476;
Angew. Chem., Int. Ed. Engl. 1980, 19, 468-469. (b) Bennett, M. A.;
McMahon, I. J .; Turney, T. W. Angew. Chem. 1982, 94, 373; Angew.
Chem., Int. Ed. Engl. 1982, 21, 379. (c) Mann, B. E. In Comprehensive
Organometallic Chemistry; Wilkinson, G., Stone, F. G. A., Abel, E. W.,
Eds.; Pergamon: Oxford, 1982; Vol. 3, Chapter 20, p 141. (d) Brookhart,
M.; Buck, R. C.; Danielson, E., III. J . Am. Chem. Soc. 1989, 111, 567-
574. (e) Spencer, J . L.; Crascall, L. E. J . Chem. Soc., Dalton Trans.
1992, 3445-3452. (f) Bennett, M. A.; Goh, L. Y.; McMahon, I. J .;
Mitchell, T. R. B.; Robertson, G. B.; Turney, T. W.; Wrickmasinghe,
W. A. Organometallics 1992, 11, 3069-3085. (g) Fryzuk, M. D.;
McConville, D. H.; Rettig, S. J . J . Organomet. Chem. 1993, 445, 245-
256. (h) Werner, H.; Scha¨fer, M.; Nu¨rnberg, O.; Wolf, J . Chem. Ber.
1994, 127, 27-38.
The reaction of 17 with HBF4 in ether leads to the
diphenylmethyliridium(III) complex 22, for which the
structure shown in Scheme 6 is proposed. The dark red
solid is readily soluble in methanol and dichloromethane
but insoluble in benzene and ether, in agreement with
(26) Bosch, M.; Laubender, M.; Weberndo¨rfer, B.; Werner, H. Chem.
Eur. J . 1999, 5, 2203-2211.
(29) Brookhart, M.; Grant, B.; Volpe, A. F., J r. Organometallics 1992,
11, 3920-3922.

Carbene Ir(I) and Ir(III) Complexes
Organometallics, Vol. 21, No. 12, 2002 2375
of gaseous HCl to 14 in benzene. If this reaction is
monitored by 31P NMR spectroscopy (in C6D6), after 1
min the signal of the starting material at δ 4.2 disap-
peared and is replaced by a new signal at δ 1.7, which
in analogy with the related allenylidene compound
[IrHCl2(dCdCdCPh2)(PiPr3)2]30 can be assigned to the
six-coordinate hydridoiridium(III) complex 26. The pres-
ence of an Ir-H bond is indicated by the high-field
resonance in the 1H NMR spectrum at δ -19.23, the
chemical shift of which is similar to that of [IrHCl2-
(dCdCdCPh2)(PiPr3)2] (δ -17.63). Attempts to isolate
26 by partial removal of the solvent and addition of
pentane led to a green solid, which besides the expected
product contains some impurities including 14. Equally
labile appears the mixed-ligand complex 27 (see Scheme
7), which has been prepared from 8 and excess HCl and
1
for which apart from the doublet at δ -18.78 in the H
NMR spectrum also a deep green color is characteristic.
We note in this context that upon treatment of trans-
[RhCl(dCPh2)(PiPr3)2] with HCl, the (red) pentacoor-
dinate alkylrhodium(III) derivative [RhCl2(CHPh2)-
(PiPr3)2] is formed, which seems to be significantly more
stable than the carbene(hydrido) isomer.3a
4. Rea ction s of th e Squ a r e-P la n a r Ir id iu m Ca r -
ben es w ith Alk en es a n d Alk yn es. The cationic irid-
ium(III) species [IrHCl(dCPh2)(PiPr3)(L)]+ (L ) PiPr3,
SbiPr3), which owing to the 16-electron configuration
and the coordination number five of the metal center
can be compared with the Grubbs-type catalyst [RuCl2-
(dCHPh)(PCy3)2],31 is completely inert toward olefins
such as ethene, 1-hexene, and cyclopentene. Even after
stirring a solution of 23, 24, or 25 in CD2Cl2 with an
excess of the respected olefin for 3-4 days, the starting
material can be recovered unchanged.
In contrast to the five-coordinate iridium(III) com-
plexes 23-25, the square-planar iridium(I) compounds
8 and 14 react slowly with C2H4 to give two new olefins,
29 and 30, in addition to the ethene derivatives 18 and
28, respectively (see Scheme 8). Due to the different
donor strength of SbiPr3 and PiPr3, it is not unexpected
that the reaction of 8 with C2H4 is faster than that of
14. The trisubstituted olefin 30, which is the product of
the catalytic reaction of C2H4 and Ph2CN2 with rhod-
ium(I) complexes such as [RhCl(PiPr3)2]2 and [RhCl-
(C2H4)2]2 as catalysts,32 is formally built up by two
carbene fragments, one originating from the CPh2 ligand
of 8 or 14 and the other from ethene. The dominating
terminal olefin 29 is obviously generated by insertion
of the CPh2 unit into one of the C-H bonds of ethene.
Although any mechanistic scheme for the formation of
the two isomers 29 and 30 from 8 or 14 remains highly
speculative, the assumption that a carbene(ethene)-
iridium complex [IrCl(dCPh2)(C2H4)(L)] or [IrCl(dCPh2)-
(C2H4)(PiPr3)(L)] (L ) PiPr3, SbiPr3) is involved in the
catalytic cycle seems to be reasonable. It is rather
surprising that in neither case, with 8 or with 14 and
C2H4 as starting materials, the formation of a third
isomer of composition C3H4Ph2, namely, 1,2-diphenyl-
F igu r e 4. Molecular diagram of compound 24 (the position
of the metal-bonded hydrogen atom H100 has been refined
isotropically). Selected bond distances (Å) and angles
(deg): Ir-Cl 2.378(2), Ir-P1 2.392(2), Ir-P2 2.409(2), Ir-
C1 1.921(7), C1-C30 1.474(8), C1-C40 1.481(9); Cl-Ir-
P1 86.05(6), Cl-Ir-P2 85.70(7), Cl-Ir-C1 158.66(18), C1-
Ir-P1 95.3(2), C1-Ir-P2 98.0(2), P1-Ir-P2 162.37(6), Ir-
C1-C30 128.8(5), Ir-C1-C40 115.5(4), C30-C1-C40
115.6(6).
25 reveal that in the solid state unsolvated species are
1
present. The H NMR spectra of 23-25 show a high-
field resonance (triplet) at, respectively, δ -28.84 (23),
-28.82 (24), and -31.20 (25) for the hydrido ligand,
whereas the 13C NMR spectra display a low-field signal
at about δ 266 for the carbene carbon atom. The
appearance of this 13C NMR signal at significantly lower
field compared to 8 and 14 could be due at least partly
to the fact that the carbene(hydrido) complexes are
cationic. A pertinent spectroscopic feature is that in both
the 1H and 13C NMR spectra of 23-25 two sets of
signals for the protons and carbon atoms of the C6H5
groups are observed, indicating that the two six-
membered rings are stereochemically not equivalent.
To elucidate the coordination geometry of the
IrH(dCPh2) derivatives, an X-ray crystal structure
analysis of 24 has been carried out. The molecular
diagram reveals (see Figure 4) that the two phosphines,
the chloride, and the carbene unit are linked in a
distorted square-planar fashion to the metal center,
forming together with the hydride a square pyramid.
Compared with the precursor compound 14, the Cl-
Ir-C1 axis of 24 is somewhat more bent (158.7(2)° vs
166.7(2)°), while the P1-Ir-P2 bond angle of 24 is
virtually identical to that of 14. The Ir-C1 bond length
of 24 (1.921(7) Å) is slightly longer than in 14 (1.887(5)
Å), which is probably due to the decrease of back-
bonding in the cationic species. This aspect is also
reflected in the slight elongation of the Ir-P1 and Ir-
P2 distances, which are 2.392(2) and 2.409(2) Å in 24
but 2.344(1) and 2.374(1) Å in 14.
The free coordination site of the carbene(hydrido)-
iridium(III) cations is readily occupied by chloride, and
thus upon addition of an aqueous solution of NaCl to a
solution of 23 in CD2Cl2, the neutral compound 26 is
formed. However, this molecule is quite labile and in
benzene/water eliminates HCl to regenerate 14. An
alternative route to 26 consists of the oxidative addition
(30) Ilg, K.; Werner, H. Chem. Eur. J . 2001, 7, 4633-4639.
(31) (a) Schwab, P.; France, M. B.; Ziller, J . W.; Grubbs, R. H. Angew.
Chem. 1995, 107, 2179-2181. (b) Schwab, P.; Grubbs, R. H.; Ziller, J .
W. J . Am. Chem. Soc. 1996, 118, 100-110. (c) Trnka, T. M.; Grubbs,
R. H. Acc. Chem. Res. 2001, 34, 18-29.
(32) (a) Wolf, J .; Brandt. L.; Fries, A.; Werner, H. Angew. Chem.
1990, 102, 584-586; Angew. Chem., Int. Ed. Engl. 1990, 29, 510-512.
(b) Werner, H. J . Organomet. Chem. 1994, 475, 45-55.

2376 Organometallics, Vol. 21, No. 12, 2002
Ortmann et al.
Sch em e 8
Sch em e 9
sides resonances for the PiPr3 protons and for phenyl
protons at around δ 6.1-7.3 a broadened singlet at δ
3.78, which owing to the chemical shift probably belongs
to the CH unit of a π-allyl system. The signal for the
corresponding carbon atom appears in the 13C NMR
spectrum at δ 32.1; its assignment is supported by
1
90DEPT measurements and the H-13C coupling con-
stant of 152.6 Hz. The suggested mode of binding of the
C3Ph4 fragment to iridium in 31 is at least partly
reminiscent of that of the CHPh2 unit in 22 (see Scheme
6), where the metal also possesses the oxidation state
+III. We note that a similar η1:η3-coordinated chelating
ligand originates through coupling of the IrdCH2 group
of the above-mentioned methylene complex [Ir(dCH2)-
{κ3-N(SiMe2CH2PPh2)2}] with butadiene.35
cyclopropane, has been observed.33 Moreover, we note
that the ratio of the two olefinic products 29 and 30 is
(within the limits of GC analysis) the same, which
indicates that a common intermediatespossibly the
four-coordinate species [IrCl(dCPh2)(C2H4)(PiPr3)]sis
involved. Attempts to detect this species spectroscopi-
cally by using the more labile compound 8 as the
precursor failed.
Con clu sion s
The stibine complex 8 also reacts (C6H6, 25 °C) with
excess cyclopentene. Besides two products containing
Ir(PiPr3) or Ir(PiPr3)2 as the molecular unit, three
organic molecules could be identified by GC/MS of which
one undoubtedly is diphenylmethylenecyclopentane.
The second compound (equally with m/z 234) is an
isomer of Ph2CdC5H8, presumably diphenylmethylcy-
clopentene, while the third (m/z 232) has two hydrogens
less and could also be a cyclopentene derivative. Since
none of the etheneiridium(I) complexes 2, 18, or 28
behaves as a catalyst for the reaction of Ph2CN2 with
olefins,32,34 a detailed analysis of the composition of the
organic products has not been carried out.
In contrast to 2, which upon treatment with diphe-
nylacetylene in pentane at room temperature gives
compound 5 by substitution of ethene (see Scheme 2),
the related stibine complex 8 reacts with C2Ph2 under
the same conditions to afford a C-C coupling product
31, for which the structure shown in Scheme 9 is
tentatively assigned. The 1H NMR spectrum of the
brown thermally stable solid displays (in CD2Cl2) be-
The present investigations have shown that in con-
trast to [IrCl(C2H4)2(SbiPr3)2] and trans-[IrCl(C2H4)-
(PiPr3)2] the mixed-ligand complex [IrCl(C2H4)(SbiPr3)-
(PiPr3)] (2) is a convenient starting material for the
preparation of four-coordinate iridium(I) carbenes 8-10.
While 2 reacts with diaryldiazomethanes to give the
carbene derivatives, the corresponding reaction of 2 with
C5Cl4N2 affords the diazoalkane compound 11 without
elimination of N2. Similarly to the rhodium(I) complexes
trans-[RhCl(dCR2)(SbiPr3)2], which upon treatment
with tertiary phosphines yield trans-[RhCl(dCR2)-
(PR3)2],2,3 the iridium analogues 8-10 equally react with
PiPr3 by ligand substitution to give the bis(phosphine)
counterparts 14-16. The lability of the Ir-SbiPr3 bond
in 8 has also been used for the preparation of the half-
sandwich-type compound 17, which is not accessible
from 14 and NaC5H5.
The square-planar representatives 8 and 14, contain-
ing a metal center with a 16-electron configuration, and
the cyclopentadienyl derivative 17, containing a metal
center with an 18-electron configuration, behave differ-
ently toward acids HBX4. While the 16-electron species
react with HBX4 (X ) F, ArF) via proton attack at
iridium(I) to give cationic complexes with IrH(dCPh2)
(33) Rhodium(II) complexes are very efficient catalysts for the
cyclopropanation of olefins with diazoalkanes; see: Padwa, A.; Austin,
D. J .; Price, A. T.; Semones, M. A.; Doyle, M. P.; Protopopova, M. N.;
Winchester, W. R.; Tran, A. J . Am. Chem. Soc. 1993, 115, 8669-8680,
and references therein.
(34) Werner, H.; Schneider, M. E.; Bosch, M.; Wolf, J .; Teuben, J .
H.; Meetsma, A.; Troyanov, S. I. Chem. Eur. J . 2000, 6, 3052-3059.
(35) Fryzuk, M. D.; Gao, X.; Rettig, S. J . Organometallics 1995, 14,
4236-4241.

Carbene Ir(I) and Ir(III) Complexes
Organometallics, Vol. 21, No. 12, 2002 2377
(81.0 MHz, C6D6): δ 41.8 (s). Anal. Calcd for C19H42ClIrOPSb:
C, 34.22; H, 6.35. Found: C, 33.98; H, 6.18.
as a molecular unit, treatment of 17 with HBF4 yields
a product having a CHPh2 ligand that is probably η3-
coordinated to the metal. The reaction of 17 with HCl
also generates an Ir(CHPh2) compound, but in this case
the diphenylmethyl unit is η1-bonded. The formation
(and structural characterization) of the cationic species
[IrHCl(dCPh2)(PiPr3)(EiPr3)]+ deserves particular at-
tention insofar as, to the best of our knowledge, stable
carbene(hydrido)iridium complexes with the metal in
either the oxidation state +I or +III are quite rare.36
Various attempts in our laboratory to generate related
carbene(hydrido)rhodium cations failed.3c,17 Finally it
should be noted that, although the iridium(I) carbenes
8 and 14 react with ethene by C-C coupling, no olefin
metathesis occurs and no IrdCH2 derivatives could be
isolated.
Gen er a tion of [Ir Cl(C2H4)2(P iP r 3)(SbiP r 3)] (4). A slow
stream of ethene was passed for 15 s through a solution of 2
(23 mg, 0.03 mmol) in C6D6 (0.4 mL) at room temperature.
The NMR spectra confirmed the formation of 4. Attempts to
isolate the bis(ethene) complex by concentrating the solution
at 5 °C in vacuo led to the regeneration of 2. Data for 4: 1H
NMR (200 MHz, C6D6): δ 3.10-3.50 (br m, 6 H, C2H4], 2.66
(m, 5 H, C2H4 and SbCHCH3), 2.29 (m, 3 H, PCHCH3), 1.47
(d, 3J (HH) ) 7.3 Hz, 18 H, SbCHCH3), 0.86 (dd, 3J (PH) ) 12.4,
3J (HH) ) 7.3 Hz, 18 H, PCHCH3). 31P NMR (81.0 MHz,
C6D6): δ -3.4 (s).
P r ep a r a tion of [Ir Cl(P h CtCP h )(P iP r 3)(SbiP r 3)] (5). A
solution of 2 (86 mg, 0.13 mmol) in pentane (10 mL) was
treated with diphenylacetylene (23 mg, 0.13 mmol) and stirred
for 3 h at room temperature. A smooth change of color from
orange to bright red occurred. The solvent was removed in
vacuo, and the residue was dissolved in acetone (1.5 mL). After
the solution was stored for 12 h at -78 °C, bright red crystals
precipitated, which were separated from the mother liquor,
washed with a small amount of acetone (-20 °C), and dried:
Exp er im en ta l Section
All reactions were carried out under an atmosphere of argon
by Schlenk techniques. Solvents were dried by known proce-
dures and distilled before use. The starting materials 1,6 12,8
and 184 were prepared as described in the literature. NMR
spectra were recorded on Bruker AC 200 and Bruker AMX
400 instruments at room temperature. IR spectra were re-
corded on a Bruker IFS 25 FT-IR and mass spectra on a
Hewlett-Packard G 1800 GCD instrument. Melting points
were measured by DTA. The term vt indicates a virtual triplet,
yield 75 mg (71%); mp 54 °C. IR (KBr): ν(CtC) 1831 cm-1
.
1H NMR (400 MHz, C6D6): δ 8.27 (m, 4 H, ortho-H of C6H5),
7.21 (m, 4 H, meta-H of C6H5), 7.06 (m, 2 H, para-H of C6H5),
2.38 (m, 3 H, PCHCH3), 2.05 (sept, 3J (HH) ) 7.6 Hz, 3 H,
3
SbCHCH3), 1.26 (d, J (HH) ) 7.6 Hz, 18 H, SbCHCH3), 0.86
(dd, 3J (PH) ) 13.1, 3J (HH) ) 7.2 Hz, 18 H, PCHCH3). 13C NMR
(100.6 MHz, C6D6): δ 129.9, 128.3, 126.2 (all s, C6H5), 71.8 (d,
2J (PC) ) 2.0 Hz, tCC6H5), 22.8 (d, 1J (PC) ) 25.4 Hz,
PCHCH3), 22.1 (s, SbCHCH3), 20.3 (s, PCHCH3), 18.2 (d,
3J (PC) ) 7.1 Hz, SbCHCH3). 31P NMR (162.0 MHz, C6D6): δ
14.9 (s). Anal. Calcd for C32H52ClIrPSb: C, 47.04; H, 6.41.
Found: C, 46.76; H, 6.13.
3
5
3
and N ) J (PH) + J (PH) or 1J (PC) + J (PC).
P r ep a r a tion of [Ir Cl(C2H4)(P iP r 3)(SbiP r 3)] (2). A sus-
pension of 1 (105 mg, 0.13 mmol) in pentane (5 mL) was
treated under stirring with SbiPr3 (52 µL, 0.25 mmol) at room
temperature. After 5 mL of benzene was added to the reaction
mixture, the solvent was evaporated in vacuo as long as a clear
orange solution was formed. The solution was stirred for 30
min and then brought to dryness in vacuo. The remaining
bright orange solid was washed twice with 1 mL portions of
pentane (0 °C) and dried: yield 159 mg (95%); mp 88 °C dec.
1H NMR (400 MHz, C6D6): δ 2.28 (br m, 10 H, SbCHCH3,
PCHCH3, and C2H4), 1.42 (d, 3J (HH) ) 7.4 Hz, 18 H, Sb-
P r ep a r a tion of [Ir H2Cl(C2H4)(P iP r 3)(SbiP r 3)] (6). A
slow stream of H2 was passed for 10 s through a solution of 2
(81 mg, 0.12 mmol) in pentane (10 mL) at -40 °C. A change
of color from orange to pale yellow occurred. The solution was
concentrated at -20 °C in vacuo to ca. 1 mL and then stored
at -78 °C for 12 h. Pale yellow crystals precipitated, which
were separated from the mother liquor and dried at 0 °C: yield
68 mg (84%); mp 58 °C dec. IR (KBr): ν(Ir-H) 2201, 2093 cm-1
.
3
3
1H NMR (200 MHz, C6D6): δ 3.18 (s, 4 H, C2H4), 2.38 (m, 3 H,
CHCH3), 1.23 (dd, J (PH) ) 12.6 Hz, J (HH) ) 7.0 Hz, 18 H,
PCHCH3). 13C NMR (100.6 MHz, C6D6): δ 22.1 (s, SbCHCH3),
3
PCHCH3), 2.25 (sept, J (HH) ) 7.2 Hz, 3 H, SbCHCH3), 1.33,
1
3
20.2 (d, J (PC) ) 25.4 Hz, PCHCH3), 20.0 (s, PCHCH3), 17.5
1.23 (both d, J (HH) ) 7.2 Hz, 9 H each, SbCHCH3), 1.20 (m,
(d, 3J (PC) ) 6.1 Hz, SbCHCH3), 14.0 (s, C2H4). 31P NMR (162.0
MHz, C6D6): δ 15.5 (s). Anal. Calcd for C20H46ClIrPSb: C,
36.02; H, 6.95. Found: C, 35.77; H, 6.70.
9 H, PCHCH3), 1.05 (dd, 3J (PH) ) 13.8, 3J (HH) ) 7.1 Hz, 9 H,
2
2
PCHCH3), -10.89 (dd, J (PH) ) 16.3, J (HH) ) 6.3 Hz, 1 H,
2
2
IrH), -28.24 (dd, J (PH) ) 13.2, J (HH) ) 6.3 Hz, 1 H, IrH).
13C NMR (50.3 MHz, C6D6): δ 41.7 (s, C2H4), 27.6 (d, 1J (PC) )
27.7 Hz, PCHCH3), 21.5, 21.3, 20.1, 19.9 (all s, SbCHCH3 and
PCHCH3), 17.9 (d, 3J (PC) ) 4.6 Hz, SbCHCH3). 31P NMR (81.0
MHz, C6D6): δ 26.5 (s). Anal. Calcd for C20H48ClIrPSb: C,
35.91; H, 7.23. Found: C, 35.17; H, 6.77.
P r ep a r a tion of [Ir Cl(CO)(P iP r 3)(SbiP r 3)] (3). A slow
stream of CO was passed for 10 s through a solution of 2 (119
mg, 0.18 mmol) in pentane (10 mL) at room temperature. A
quick change of color from orange to yellow occurred. The
solvent was evaporated in vacuo, the residue was dissolved in
pentane (2 mL), and the solution was stored for 12 h at -78
°C. Lemon-yellow crystals precipitated, which were separated
from the mother liquor, washed twice with 1 mL portions of
pentane (0 °C), and dried: yield 96 mg (80%); mp 146 °C. IR
P r ep a r a tion of [Ir H 2Cl(P iP r 3)(SbiP r 3)] (7a /7b). A solu-
tion of 6 (98 mg, 0.15 mmol) in hexane (20 mL) was stirred
under a H2 atmosphere (1 bar) for 30 min at room temperature.
A gradual change of color from pale yellow to yellow occurred.
After the solvent was evaporated in vacuo, the oily residue
was dissolved in acetone (1 mL), and the solution was stored
-78 °C for 12 h. A yellow microcrystalline solid precipitated,
which was separated from the mother liquor and dried (at
room temperature the solid is partly converted to an oil): yield
39 mg (42%). IR (KBr): ν(Ir-H) 2162, 2110 cm-1. Anal. Calcd
for C18H44ClIrPSb: C, 33.73; H, 6.92. Found: C, 33.88; H, 6.80.
NMR data for 7a : 1H NMR (400 MHz, C6D6): δ 2.41 (m, 3 H,
(KBr): ν(CO) 1926 cm-1 1H NMR (200 MHz, C6D6): δ 2.62
.
(m, 3 H, PCHCH3), 2.35 (sept, 3J (HH) ) 7.3 Hz, 3 H,
3
SbCHCH3), 1.42 (d, J (HH) ) 7.3 Hz, 18 H, SbCHCH3), 1.26
3
3
(dd, J (PH) ) 13.9 Hz, J (HH) ) 7.3 Hz, 19 H, PCHCH3). 13C
NMR (50.3 MHz, C6D6): δ 171.9 (d, 2J (PC) ) 10.2 Hz, CO),
1
24.4 (d, J (PC) ) 24.4 Hz, PCHCH3), 21.8 (s, SbCHCH3), 19.8
(s, PCHCH3), 19.0 (d, J (PC) ) 4.6 Hz, SbCHCH3). 31P NMR
3
3
PCHCH3), 2.15 (sept, J (HH) ) 7.6 Hz, 3 H, SbCHCH3), 1.44
(36) (a) Nemeh, S.; Flesher, R. J .; Gierling, K.; Maichle-Mo¨ssmer,
C.; Mayer, H. A.; Kaska, W. C. Organometallics 1998, 17, 2003-2008.
(b) Alias, F. M.; Poveda, M. L.; Sellin, M.; Carmona, E.; Gutierrez-
Puebla, E.; Monge, A. Organometallics 1998, 17, 4124-4126. (c) Alias,
F. M.; Poveda, M. L.; Sellin, M.; Carmona, E. J . Am. Chem. Soc. 1998,
120, 5816-5817. (d) Luecke, H. F.; Bergman, R. G. J . Am. Chem. Soc.
1998, 120, 11008-11009.
(d, 3J (HH) ) 7.6 Hz, 18 H, SbCHCH3), 1.21 (dd, 2J (PH) ) 13.7,
2
3J (HH) ) 7.6 Hz, 18 H, PCHCH3), -25.31 (d, J (PH) ) 20.2
Hz, 2 H, IrH). 31P NMR (81.0 MHz, C6D6): δ 50.9 (s). NMR
data for 7b: 1H NMR (400 MHz, C6D6): δ 2.38 (m, 3 H,
3
PCHCH3), 2.22 (sept, J (HH) ) 7.6 Hz, 3 H, SbCHCH3], 1.45

2378 Organometallics, Vol. 21, No. 12, 2002
Ortmann et al.
(d, 3J (HH) ) 7.6 Hz, 9 H, SbCHCH3), 1.38 (dd, 2J (PH) ) 13.7,
PCHCH3). 13C NMR (100.6 MHz, C6D6): δ 108.7, 99.3 (both s,
C4Cl4), 63.8 (s, CN2), 23.7 (d, 1J (PC) ) 25.4 Hz, PCHCH3), 21.8
(s, SbCHCH3), 19.8 (d, 3J (PC) ) 5.1 Hz, SbCHCH3), 19.6 (s,
PCHCH3). 31P NMR (81.0 MHz, C6D6): δ 28.9 (s). Anal. Calcd
for C23H42Cl5IrN2PSb: C, 31.80; H, 4.87; N, 3.22. Found: C,
31.82; H, 4.74; N, 3.21.
3
3J (HH) ) 6.8 Hz, 9 H, PCHCH3), 1.33 (d, J (HH) ) 7.6 Hz, 9
2
3
H, SbCHCH3), 1.09 (dd, J (PH) ) 13.7, J (HH) ) 6.8 Hz, 9 H,
2
2
PCHCH3), -15.93 (dd, J (PH) ) 15.2, J (HH) ) 6.1 Hz, 1 H,
IrH), -26.47 (dd, J (PH) ) 13.7, J (HH) ) 6.1 Hz, 1 H, IrH).
2
2
31P NMR (81.0 MHz, C6D6): δ 37.0 (s).
P r ep a r a tion of tr a n s-[Ir Cl(N2C5Cl4)(Sb iP r 3)2] (13). A
solution of 12 (49 mg, 0.06 mmol) in pentane (5 mL) was
treated with a solution of C5Cl4N2 (13 mg, 0.06 mmol) in ether
(3 mL) at room temperature. A rapid change of color from
orange to dark green occurred. The reaction mixture was
worked up as described for 11 to give a dark green microcrys-
talline solid: yield 45 mg (82%); mp 93 °C dec. IR (KBr): ν-
(N2) 1830 cm-1. 1H NMR (200 MHz, C6D6): δ 2.25 (sept, 3J (HH)
) 7.3 Hz, 6 H SbCHCH3), 1.25 (d, 3J (HH) ) 7.3 Hz, 36 H,
SbCHCH3). 13C NMR (100.6 MHz, C6D6): δ 108.1, 99.3 (both
s, C4Cl4), 61.0 (s, CN2), 21.8 (s, SbCHCH3), 20.2 (s, SbCHCH3).
Anal. Calcd for C23H42Cl5IrN2Sb2: C, 28.79; H, 4.41; N, 2.92.
Found: C, 28.76; H, 4.22; N, 2.75.
P r ep a r a tion of [Ir Cl(dCP h 2)(P iP r 3)(SbiP r 3)] (8). A
solution of 2 (121 mg, 0.18 mmol) in benzene (10 mL) was
treated with Ph2CN2 (35 mg, 0.18 mmol) at room temperature.
A change of color from orange to dark red, accompanied by an
evolution of gas, occurred. After the reaction mixture was
stirred at ca. 0.2 bar for 1 h, the solvent was evaporated in
vacuo and the residue recrystallized from acetone (2 mL).
Storing the solution at -78 °C for 12 h led to the formation of
a brown microcrystalline solid, which was washed with a small
amount of acetone (-20 °C) and dried: yield 105 mg (72%);
mp 42 °C dec. 1H NMR (200 MHz, C6D6): δ 7.87 (m, 4 H,
ortho-H of C6H5), 7.40 (m, 2 H, para-H of C6H5), 6.96 (m, 4 H,
3
meta-H of C6H5), 2.39 (m, 3 H, PCHCH3), 2.11 (sept, J (HH)
) 7.3 Hz, 3 H, SbCHCH3), 1.32 (d, 3J (HH) ) 7.3 Hz, 18 H,
P r ep a r a t ion of tr a n s-[Ir Cl(dCP h 2)(P iP r 3)2] (14). A
solution of 8 (200 mg, 0.28 mmol) in pentane (20 mL) was
treated with PiPr3 (55 µL, 0.28 mmol) and stirred for 45 min
at room temperature. The solvent was evaporated in vacuo
and the residue recrystallized from acetone (2 mL) at -78 °C
3
3
SbCHCH3), 1.19 (dd, J (PH) ) 13.2, J (HH) ) 7.3 Hz, 18 H,
PCHCH3). 13C NMR (50.3 MHz, C6D6): δ 240.9 (d, 2J (PC) )
7.6 Hz, IrdC), 175.3 (s, ipso-C of C6H5), 128.5, 127.9, 126.8
(all s, C6H5), 24.8 (d, 1J (PC) ) 24.2 Hz, PCHCH3), 22.0 (s,
SbCHCH3), 20.0 (s, PCHCH3), 18.9 (d, 3J (PC) ) 5.1 Hz,
SbCHCH3). 31P NMR (81.0 MHz, C6D6): δ 8.8 (s). Anal. Calcd
for C31H52ClIrPSb: C, 46.24; H, 6.51. Found: C, 46.49; H, 6.43.
P r ep a r a tion of [Ir Cl{dC(p-C6H4Me)2}(P iP r 3)(SbiP r 3)]
(9). This compound was prepared as described for 8 from 2
(112 mg, 0.17 mmol) and (p-C6H4Me)2CN2 (38 mg, 0.17 mmol).
Dark brown microcrystalline solid: yield 83 mg (59%); mp 24
1
to give a brown solid: yield 112 mg (56%); mp 83 °C dec. H
NMR (400 MHz, C6D6): δ 7.87 (br m, 4 H, ortho-H of C6H5),
7.42 (m, 2 H, para-H of C6H5), 6.96 (m, 4 H, meta-H of C6H5),
2.44 (m, 6 H, PCHCH3), 1.20 (dvt, N ) 13.2, 3J (HH) ) 7.0 Hz,
36 H, PCHCH3). 13C NMR (100.6 MHz, C6D6): δ 234.7 (t,
2J (PC) ) 8.9 Hz, IrdC), 175.0 (s, ipso-C of C6H5), 128.3, 128.2,
127.0 (all s, C6H5), 25.2 (vt, N ) 25.4 Hz, PCHCH3), 20.4 (s,
PCHCH3). 31P NMR (81.0 MHz, C6D6): δ 4.2 (s). Anal. Calcd
for C31H52ClIrP2: C, 52.12; H, 7.34; Ir, 26.91. Found: C, 51.92;
H, 7.35; Ir, 27.10.
1
°C dec. H NMR (200 MHz, C6D6): δ 7.91 (m, 4 H, ortho-H of
C6H4), 6.81 (m, 4 H, meta-H of C6H4), 2.44 (m, 3 H, PCHCH3),
2.17 (sept, 3J (HH) ) 7.3 Hz, 3 H, SbCHCH3), 1.73 (s, 6 H,
C6H4CH3), 1.36 (d, 3J (HH) ) 7.3 Hz, 18 H, SbCHCH3), 1.24
(dd, 3J (PH) ) 13.3, 3J (HH) ) 7.2 Hz, 18 H, PCHCH3). 13C NMR
(50.3 MHz, CD2Cl2): δ 244.7 (d, 2J (PC) ) 7.6 Hz, IrdC), 171.5
(s, ipso-C of C6H4), 137.3, 129.3, 128.6 (all s, C6H4), 25.0 (d,
1J (PC) ) 25.4 Hz, PCHCH3), 22.3 (s, C6H4CH3), 22.1 (s,
SbCHCH3), 20.1 (s, PCHCH3), 19.1 (d, 3J (PC) ) 5.1 Hz,
SbCHCH3). 31P NMR (81.0 MHz, C6D6): δ 9.9 (s). Anal. Calcd
for C33H56ClIrPSb: C, 47.57; H, 6.77; Ir, 23.07; Sb, 14.61.
Found: C, 47.33; H, 6.74; Ir, 22.75; Sb, 14.50.
P r ep a r a t ion of tr a n s-[Ir Cl{dC(p -C6H 4Me)2}(P iP r 3)2]
(15). This compound was prepared as described for 14 from 9
(250 mg, 0.30 mmol) and PiPr3 (64 µL, 0.33 mmol). Deep brown
1
microcrystalline solid: yield 136 mg (61%); mp 56 °C dec. H
NMR (200 MHz, C6D6): δ 7.89 (br m, 4 H, ortho-H of C6H4),
6.81 (m, 4 H, meta-H of C6H4), 2.50 (m, 6 H, PCHCH3), 1.73
(s, 6 H, C6H4CH3), 1.23 (dvt, N ) 13.2, 3J (HH) ) 7.0 Hz, 36 H,
PCHCH3). 13C NMR (50.3 MHz, C6D6): δ 245.5 (d, 2J (PC) )
8.9 Hz, IrdC), 172.2 (d, 3J (PC) ) 3.8 Hz, ipso-C of C6H4), 136.9,
129.0, 128.8 (all s, C6H4), 25.2 (vt, N ) 25.4 Hz, PCHCH3),
21.9 (s, C6H4CH3), 20.4 (s, PCHCH3). 31P NMR (81.0 MHz,
C6D6): δ 5.7 (s). Anal. Calcd for C33H56ClIrP2: C, 53.39; H,
7.60; Ir, 25.89; P, 8.34. Found: C, 53.32; H, 7.72; Ir, 26.20; P,
8.20.
P r epar ation of tr a n s-[Ir Cl{dC(p-C6H4Cl)2}(P iP r 3)2] (16).
A solution of 10 (83 mg, 0.10 mmol) in benzene (10 mL) was
treated with PiPr3 (19 µL, 0.10 mmol) and stirred for 2 h at
room temperature. After evaporation of the solvent in vacuo,
an oily brownish residue was obtained, which could not be
converted to a crystalline, analytically pure solid. Spectroscopic
data: 1H NMR (200 MHz, C6D6): δ 7.54 (m, 4 H, ortho-H of
C6H4), 6.92 (m, 4 H, meta-H of C6H4), 2.35 (m, 6 H, PCHCH3),
1.10 (dvt, N ) 13.5, 3J (HH) ) 7.3 Hz, 36 H, PCHCH3). 13C
NMR (50.3 MHz, C6D6): δ 237.8 (t, 2J (PC) ) 8.9 Hz, IrdC),
173.6 (s, ipso-C of C6H4), 133.2, 128.5, 128.3 (all s, C6H4), 25.0
(vt, N ) 25.4 Hz, PCHCH3), 20.2 (s, PCHCH3). 31P NMR (81.0
MHz, C6D6): δ 3.5 (s).
P r ep a r a t ion of [Ir Cl{dC(p -C6H 4Cl)2}(P iP r 3)(SbiP r 3)]
(10). This compound was prepared as described for 8 from 2
(112 mg, 0.17 mmol) and (p-C6H4Cl)2CN2 (38 mg, 0.17 mmol).
After recrystallization from pentane at -78 °C a brown
microcrystalline solid was obtained: yield 90 mg (61%); mp
1
39 °C dec. H NMR (200 MHz, C6D6): δ 7.57 (m, 4 H, ortho-H
of C6H4), 6.93 (m, 4 H, meta-H of C6H4), 2.30 (m, 3 H,
3
PCHCH3), 2.08 (sept, J (HH) ) 7.3 Hz, 3 H, SbCHCH3), 1.24
(d, 3J (HH) ) 7.3 Hz, 18 H, SbCHCH3), 1.12 (dd, 3J (PH) ) 13.5,
3J (HH) ) 7.3 Hz, 18 H, PCHCH3). 13C NMR (50.3 MHz,
2
C6D6): δ 235.7 (d, J (PC) ) 7.4 Hz, IrdC), 173.8 (s, ipso-C of
1
C6H4), 132.9, 129.0, 128.8 (all s, C6H4), 25.0 (d, J (PC) ) 25.9
Hz, PCHCH3), 21.9 (s, SbCHCH3), 19.9 (s, PCHCH3), 19.2 (d,
3J (PC) ) 4.6 Hz, SbCHCH3). 31P NMR (81.0 MHz, C6D6): δ
8.4 (s). Anal. Calcd for C31H50Cl3IrPSb: C, 42.59; H, 5.77.
Found: C, 42.13; H, 5.35.
P r ep a r a tion of [Ir Cl(N2C5Cl4)(P iP r 3)(SbiP r 3)] (11). A
solution of 2 (76 mg, 0.11 mmol) in pentane (10 mL) was
treated with C5Cl4N2 (25 mg, 0.11 mmol), which led to an
instantaneous change of color from orange to dark green. After
the reaction mixture was stirred for 30 min at room temper-
ature, a dark green solid precipitated, which was separated
from the mother liquor, washed with pentane (10 mL), and
recrystallized from acetone (4 mL) at -78 °C to give dark green
crystals: yield 90 mg (94%); mp 114 °C dec. IR (KBr): ν(N2)
P r ep a r a tion of [(η5-C5H5)Ir (dCP h 2)(P iP r 3)] (17). A solu-
tion of 8 (138 mg, 0.19 mmol) in THF (25 mL) was treated
with portions of ca. 15 mg of NaC5H5 (85.1 mg, 0.97 mmol),
and the mixture was stirred for 1 h at room temperature. The
solvent was evaporated in vacuo, the residue was dissolved in
pentane (20 mL), and the solution was filtered. After the
filtrate was brought to dryness in vacuo, the remaining red-
brown oil was recrystallized from pentane (2 mL) at -78 °C
to give a dark brown microcrystalline solid: yield 77 mg (70%);
mp 93 °C dec. 1H NMR (200 MHz, C6D6): δ 7.42 (m, 4 H,
1839 cm-1
.
1H NMR (200 MHz, C6D6): δ 2.33 (m, 6 H,
SbCHCH3 and PCHCH3), 1.27 (d, 3J (HH) ) 7.3 Hz, 18 H,
3
3
SbCHCH3), 1.12 (dd, J (PH) ) 14.2, J (HH) ) 6.9 Hz, 18 H,

Carbene Ir(I) and Ir(III) Complexes
Organometallics, Vol. 21, No. 12, 2002 2379
ortho-H of C6H5), 7.10 (m, 2 H, para-H of C6H5), 6.92 (m, 4 H,
meta-H of C6H5), 4.92 (d, 3J (PH) ) 1.1 Hz, 5 H, C5H5), 1.54
Hz, PCHCH3), 19.8, 19.5 (both s, PCHCH3). 31P NMR (81.0
MHz, C6D6): δ 37.5 (s). Anal. Calcd for C27H37ClIrP: C, 52.29;
H, 6.01. Found: C, 51.98; H, 5.78.
3
3
(dsept, J (PH) ) 13.1, J (HH) ) 6.9 Hz, 3 H, PCHCH3), 0.98
(dd, 3J (PH) ) 13.1, 3J (HH) ) 6.9 Hz, 18 H, PCHCH3). 13C NMR
P r ep a r a tion of [(η5-C5H5)Ir (η3-CHP h 2)(P iP r 3)]BF 4 (22).
A solution of 17 (73 mg, 0.09 mmol) in ether (20 mL) was
treated under stirring dropwise with a 54% solution of HBF4
in ether (ca. 0.1 mL) at room temperature. A dark red solid
precipitated, the formation of which was completed after ca.
30 min. The mother liquor was decanted, and the remaining
dark red solid was washed twice with 5 mL portions of ether
and dried. Owing to the elemental analysis, the product is the
monoetherate of 22: yield 47 mg (98%); mp 126 °C dec. 1H
NMR (200 MHz, CD2Cl2): δ 7.27 (br m, 10 H, C6H5), 4.91 (d,
3J (PH) ) 1.1 Hz, 5 H, C5H5), 3.32 (d, 3J (PH) ) 12.1 Hz,
2
(50.3 MHz, C6D6): δ 217.2 (d, J (PC) ) 12.7 Hz, IrdC), 175.8
3
(s, ipso-C of C6H5), 170.6 (d, J (PC) ) 6.4 Hz, ipso-C of C6H5),
127.1, 126.6, 125.0, 124.0, 123.4, 123.3 (all s, C6H5), 82.3 (d,
1
2J (PC) ) 3.8 Hz, C5H5), 28.0 (d, J (PC) ) 28.0 Hz, PCHCH3),
20.7 (s, PCHCH3). 31P NMR (81.0 MHz, C6D6): δ 27.8 (s). Anal.
Calcd for C27H36IrP: C, 55.55; H, 6.22. Found: C, 55.34; H,
6.09.
P r ep a r a tion of [(η5-C5H5)Ir (C2H4)(SbiP r 3)] (19). A solu-
tion of 18 (200 mg, 0.25 mmol) in THF (20 mL) was treated
with NaC5H5 (27 mg, 0.30 mmol) at -78 °C and after stirring
for 10 min slowly warmed to room temperature. The solvent
was evaporated in vacuo and the remaining yellow oil ex-
tracted twice with 10 mL portions of pentane. The combined
extracts were brought to dryness in vacuo, the residue was
dissolved in hexane (2 mL), and the solution was chromato-
graphed on Al2O3 (activity grade V, height of column 5 cm).
With hexane an off-white fraction was eluted which contained
mainly SbiPr3. Subsequent elution with THF afforded a yellow
fraction, which after removal of the solvent gave a yellow oil.
Since it still contained small amounts of SbiPr3, which could
not be removed by chromatography or recrystallization, com-
3
CH(C6H5)2), 2.34 (m, 3 H, PCHCH3), 1.31 (dd, J (HH) ) 7.3,
2J (PH) ) 14.5 Hz, 18 H, PCHCH3). 13C NMR (50.3 MHz, CD2-
Cl2): δ 140-124 (br m, C6H5), 88.0 (s, C5H5), 46.4 (d, 2J (PC) )
6.4 Hz, CH(C6H5)2), 27.4 (d, 1J (PC) ) 28.0 Hz, PCHCH3), 20.2
(s, PCHCH3). 19F NMR (188.3 MHz, CD2Cl2): δ -153.0 (s). 31
P
NMR (81.0 MHz, CD2Cl2): δ 13.0 (s). Anal. Calcd for C31H47
-
BF4IrOP: C, 49.93; H, 6.35. Found: C, 49.83; H, 5.99.
P r ep a r a tion of [Ir HCl(dCP h 2)(P iP r 3)2]BF 4 (23). A solu-
tion of 14 (61 mg, 0.09 mmol) in a 1:1 mixture of pentane/
CH2Cl2 (10 mL) was treated dropwise with a 50% aqueous
solution of HBF4 until the precipitation of a red solid was
finished. The solution was decanted, and the remaining
residue was washed with distilled water (5 mL) and then
extracted with CH2Cl2 (10 mL). The extract was concentrated
to ca. 5 mL in vacuo, and pentane (20 mL) was added. After
the suspension was stored for 12 h, a dark red solid precipi-
tated, which was separated from the mother liquor, washed
with pentane (5 mL), and dried: yield 65 mg (95%); mp 91 °C
dec. 1H NMR (400 MHz, CD2Cl2): δ 7.92, 7.85 (both m, 1 H
each, C6H5), 7.76, 7.55, 7.49, 7.44 (all m, 2 H each, C6H5), 2.30
1
pound 18 was characterized by spectroscopy. H NMR (C6D6,
200 MHz): δ 4.94 (s, 5 H, C5H5), 2.36, 2.00 (both m, 2 H each,
3
C2H4), 1.76 (sept, J (HH) ) 7.1 Hz, 3 H, SbCHCH3), 1.10 (d,
3J (HH) ) 7.1 Hz, 18 H, SbCHCH3). 13C NMR (C6D6, 50.3
MHz): δ 75.1 (s, C5H5), 21.3 (s, SbCHCH3), 16.1 (s, SbCHCH3),
-3.0 (s, C2H4).
P r ep a r a tion of [(η5-C5H5)Ir Cl(CHP h 2)(P iP r 3)] (20). A
slow stream of dry HCl was passed at room temperature
through a solution of 17 (163 mg, 0.28 mmol) in pentane (5
mL) until the color of the solution turned to orange-yellow.
Storing the solution for 1 h led to the formation of an orange-
yellow precipitate, which was separated from the mother
liquor, washed twice with 1 mL portions of pentane (0 °C),
3
(m, 6 H, PCHCH3), 1.11 (dvt, N ) 15.3, J (HH) ) 7.6 Hz, 18
H, PCHCH3), 1.03 (dvt, N ) 15.3, 3J (HH) ) 7.6 Hz, 18 H,
2
PCHCH3), -28.84 (t, J (PH) ) 12.2 Hz, 1 H, IrH). 13C NMR
(50.3 MHz, CD2Cl2): δ 266.5 (s, IrdC), 157.3, 154.6 (both s,
ipso-C of C6H5), 136.7, 135.0, 133.4, 131.2, 130.9, 125.7 (all s,
1
and dried: yield 172 mg (99%); mp 60 °C dec. H NMR (200
C6H5), 24.9 (vt, N ) 28.0 Hz, PCHCH3), 19.7 (s, PCHCH3). 31
P
MHz, CD2Cl2): δ 7.30 (m, 2 H, C6H5), 7.08 (m, 4 H, C6H5), 6.88
NMR (81.0 MHz, CD2Cl2): δ 38.2 (s). 19F NMR (188.3 MHz,
CD2Cl2): δ -153.6 (s). MS (FAB; o-nitrophenyloctyl ether as
matrix): m/z 715 (M+). Anal. Calcd for C31H53BClF4IrP2: C,
46.42; H, 6.66. Found: C, 46.79; H, 6.98.
(m, 4 H, C6H5), 5.75 (d, 3J (PH) ) 2.2 Hz, 1 H, CH(C6H5)2), 5.09
3
(d, J (PH) ) 1.5 Hz, 5 H, C5H5), 2.44 (m, 3 H, PCHCH3), 1.20
(dd, 3J (PH) ) 14.4, 3J (HH) ) 7.1 Hz, 12 H, PCHCH3), 0.81
(dd, 3J (PH) ) 12.6, 3J (HH) ) 7.1 Hz, 6 H, PCHCH3). 13C NMR
3
(50.3 MHz, CD2Cl2): δ 156.7, 151.0 (both d, J (PC) ) 2.8 Hz,
P r ep a r a tion of [Ir HCl(dCP h 2)(P iP r 3)2][B(Ar F )4] (24).
A solution of 14 (74 mg, 0.10 mmol) in pentane (5 mL) was
treated with [H(OEt2)2]B(ArF)4 (105 mg, 0.10 mmol) and stirred
for 2 h at room temperature. A viscous oily precipitate was
formed, which was separated from the mother liquor and then
suspended in pentane (5 mL). Irradiating the suspension in
an ultrasound bath for 5 min led to the formation of a red-
pink solid, which was separated from the solution, washed
twice with 2 mL portions of pentane, and dried: yield 136 mg
ipso-C of C6H5), 132.2, 127.6, 126.9, 126.8, 124.5, 123.0 (all s,
2
2
C6H5), 83.1 (d, J (PC) ) 2.8 Hz, C5H5), 24.6 (d, J (PC) ) 6.5
Hz, CHPh2), 25-22, 21-18 (both br m, PCHCH3 and PCHCH3).
31P NMR (81.0 MHz, C6D6): δ 5.5 (s). Anal. Calcd for C27H37
-
ClIrP: C, 52.29; H, 6.01. Found: C, 52.54; H, 5.90.
P r ep a r a tion of [(η5-C5H4CHP h 2)Ir HCl(P iP r 3)] (21). A
solution of 20 (120 mg, 0.19 mmol) in benzene (10 mL) was
stirred under reflux for 2 min, which led to a stepwise change
of color from orange-yellow to red and then from red to yellow.
After the reaction mixture was cooled to room temperature,
the solvent was removed in vacuo and the yellow oily residue
was dissolved in CH2Cl2 (1 mL). Hexane (10 mL) was added
and the solution concentrated in vacuo until yellow crystals
precipitated. After storing for 12 h at -78 °C, the crystals were
separated from the mother liquor, washed with a small amount
of pentane (-20 °C), and dried: yield 114 mg (95%); mp 106
1
(83%); mp 151 °C dec. H NMR (200 MHz, CD2Cl2): δ 7.83-
7.39 (br m, 22 H, C6H5 and BC6H3), 2.29 (m, 6 H, PCHCH3),
1.10, 1.02 (both dvt, N ) 14.5, 3J (HH) ) 7.3 Hz, 18 H each,
2
PCHCH3), -28.82 (t, J (PH) ) 13.1 Hz, 1 H, IrH). 13C NMR
(50.3 MHz, CD2Cl2): δ 266.7 (s, IrdC), 162.4 (q, 1J (BC) ) 49.6
Hz, ipso-C of ArF), 157.5, 154.7 (both s, ipso-C of C6H5), 136.6,
135.0, 133.4, 131.2, 130.8, 125.7 (all s, C6H5), 135.4 (br s,
ortho-C of ArF), 129.5 (qq, 2J (FC) ) 31.8, 4J (FC) ) 2.4 Hz,
1
°C dec. IR (KBr): ν(Ir-H) 2153 cm-1 1H NMR (200 MHz,
.
meta-C of ArF), 125.2 (q, J (FC) ) 272 Hz, CF3), 118.1 (br s,
para-C of ArF), 24.9 (vt, N ) 28.0 Hz, PCHCH3), 19.7 (s,
C6D6): δ 7.46 (m, 4 H, C6H5), 7.08 (m, 6 H, C6H5), 5.70 (d,
4J (PH) ) 2.2 Hz, 1 H, CH(C6H5)2), 4.93 (m, 2 H, C5H4), 4.49,
4.31 (both m, 1 H each, C5H4), 2.13 (m, 3 H, PCHCH3), 0.96
PCHCH3). 31P NMR (162.0 MHz, CD2Cl2): δ 38.3 (s). 19F NMR
(188.3 MHz, CD2Cl2): δ -125.2 (s). Anal. Calcd for C63H65
BClF24IrP2: C, 47.93; H, 4.15. Found: C, 47.85; H, 4.10.
-
3
3
(dd, J (PH) ) 13.9, J (HH) ) 7.3 Hz, 18 H, PCHCH3), -14.40
(d, J (PH) ) 33.4 Hz, 1 H, IrH). 13C NMR (50.3 MHz, C6D6):
P r ep a r a tion of [Ir HCl(dCP h 2)(P iP r 3)(SbiP r 3)][B(Ar F)4]
(25). This compound was prepared as described for 24 from
8 (104 mg, 0.13 mmol) and [H(OEt2)2]B(ArF)4 (130 mg, 0.13
mmol). Red-pink solid: yield 183 mg (85%); mp 146 °C dec.
1H NMR (200 MHz, CD2Cl2): δ 7.90-7.38 (br m, 22 H, C6H5
2
δ 143.4, 143.3 (both s, ipso-C of C6H5), 130.3, 130.2, 128.6,
128.5, 126.7, 126.6 (all s, C6H5), 121.8 (d, 2J (PC) ) 4.6 Hz,
CCHPh2), 84.0 (s, C5H4), 77.1 (d, 2J (PC) ) 9.2 Hz, C5H4), 74.8,
67.6 (both s, C5H4), 47.9 (s, CHPh2), 26.6 (d, 1J (PC) ) 31.4

2380 Organometallics, Vol. 21, No. 12, 2002
Ta ble 1. Cr ysta llogr a p h ic Da ta for 13, 14, 17, a n d 24
Ortmann et al.
13
14
17
24
formula
M
C
23H42Cl5IrN2Sb2
C31H52ClIrP2
714.32
C27H36IrP
583.73
C63H65BClF24IrP2
1578.55
959.54
cryst size, mm
cryst syst
space group
a, Å
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
0.40 × 0.20 × 0.10
0.20 × 0.15 × 0.11
triclinic
P1h (No. 2)
10.353(5)
12.153(4)
13.909(5)
94.04(2)
93.62(2)
114.16(2)
1585(1)
0.22 × 0.16 × 0.13
0.18 × 0.16 × 0.15
monoclinic
monoclinic
monoclinic
P21/c (No. 14)
14.474(3)
8.64(2)
28.061(6)
P21/n (No. 14)
11.017(2)
14.709(2)
15.374(3)
P21/c (No. 14)
12.6422(10)
15.2941(10)
35.961(3)
90
90
90
101.64(1)
90
3439(8)
96.006(9)
90
2477.7(7)
92.732(10)
90
6945.1(9)
Z
d
4
2
4
4
calcd, g cm-3
1.853
1.497
1.565
1.510
T, K
293(2)
1.998
ω/θ
48
173(2)
4.416
ω/θ
52.04
293(2)
0.138
ω/θ
49.90
173(2)
2.108
φ
50.04
34995
1223 [R(int) ) 0.0591]
8581
µ, mm-1
scan method
2θ(max), deg
total no. of rflns
no. of unique rflns
no. of obsd rflns
(I > 2σ(I))
no. of rflns used for
refinement
4775
6479
4496
4556 [R(int) ) 0.2752]
2892
6208 [R(int) ) 0.0324]
5555
4328 [R(int) ) 0.0206]
3565
4556
6208
4328
12 231
no. of params refined
399
328
269
986
final R indices (I > 2σ(I))a
R1 ) 0.0494,
wR2 ) 0.0841
R1 ) 0.0967,
wR2 ) 0.1174
1.122/-1.029
R1 ) 0.0319,
wR2 ) 0.0699
R1 ) 0.0393,
wR2 ) 0.0758
1.737/-1.275
R1 ) 0.0287,
wR2 ) 0.0612
R1 ) 0.0407,
wR2 ) 0.0696
0.697/-0.568
R1 ) 0.0471,
wR2 ) 0.1259
R1 ) 0.0701,
wR2 ) 0.1259
2.233/-1.598
R indices (all data)a
resid electron density,
e Å-3
a
w ) 1/[σ2(Fo2) + (0.0186P)2 + 38.8077P] (13), w ) 1/[σ2(Fo2) + (0.0226P)2 + 7.0221P] (14), w ) 1/[σ2(Fo2) + (0.0267P)2 + 4.9566P] (17),
w ) 1/[σ2(Fo2) + (0.0833P)2 + 0.0000P] (24), where P ) [Fo + 2Fc2]/3.
2
and BC6H3), 2.35 (sept, 3J (HH) ) 7.3 Hz, 3 H, SbCHCH3), 2.29
reaction mixture was stored for 3 h under an ethene atmo-
sphere, which led to a change of color from dark red to yellow.
The 31P NMR spectrum shows the quantitative conversion of
8 to a mixture of 18 and trans-[IrCl(C2H4)(PiPr3)2] (28).6 The
1H NMR spectrum indicates the formation of a mixture of 3,3-
diphenyl-1-propene (29) and 1,1-diphenyl-1-propene (30) in the
ratio of 1.85:1 (65%:35%).37 After the solution was filtered with
Al2O3 (neutral, activity grade I), the filtrate was investigated
by GC/MS. Under these conditions, the ratio of 29 to 30 was
2.3:1. It was proved by independent studies that neither
thermally or in the presence of Al2O3 does an isomerization of
29 to 30 occur.
3
(m, 3 H, PCHCH3), 1.25, 1.20 (both d, J (HH) ) 7.3 Hz, 9 H
3
3
each, SbCHCH3), 1.10, 1.05 (both dd, J (PH) ) 14.9, J (HH)
) 7.3 Hz, 9 H each, PCHCH3), -31.20 (d, 2J (PH) ) 11.4 Hz, 1
H, IrH). 13C NMR (50.3 MHz, CD2Cl2): δ 267.7 (s, IrdC), 162.4
(q, 1J (BC) ) 49.7 Hz, ipso-C of ArF), 157.0, 153.3 (both s, ipso-C
of C6H5), 136.4, 134.7, 132.8, 131.8, 131.0, 122.7 [all s, C6H5],
135.4 (br s, ortho-C of ArF), 129.5 (qq, 2J (FC) ) 31.7, 4J (FC) )
1
2.4 Hz, meta-C of ArF), 125.2 (q, J (FC) ) 272 Hz, CF3), 118.1
(br s, para-C of ArF), 25.3 (d, 1J (PC) ) 26.7 Hz, PCHCH3), 22.7,
22.6 (both s, SbCHCH3), 22.0, 21.8 (both s, PCHCH3), 19.6 (s,
SbCHCH3). 31P NMR (162.0 MHz, CD2Cl2): δ 39.9 (s). 19F NMR
(188.3 MHz, CD2Cl2): δ -125.2 (s). Anal. Calcd for C63H65
-
R ea ct ion of tr a n s-[Ir Cl(dCP h 2)(P iP r 3)2] (14) w it h
Eth en e. This experiment was carried out analogously as
described for 8 using 14 (42 mg, (0.06 mmol) and ethene as
starting materials. Since after 3 h at room temperature no
reaction occurred, the solvent (C6D6) was removed in vacuo.
The residue was dissolved in toluene-d6 (0.5 mL), the argon
atmosphere was replaced by ethene, and the reaction mixture
BClF24IrPSb: C, 45.33; H, 3.92. Found: C, 44.88; H, 3.86.
Gen er a tion of [Ir HCl2(dCP h 2)(P iP r 3)2] (26). A slow
stream of dry HCl was passed for 1 min through a solution of
14 (45 mg, 0.06 mmol) in C6D6 (0.6 mL) at room temperature.
A quick change of color from dark red to green occurred. The
composition of the product was determined spectroscopically.
1H NMR (200 MHz, CD2Cl2): δ 8.82 (m, 2 H, C6H5), 7.51 (m,
2 H, C6H5), 7.01 (m, 6 H, C6H5), 2.61 (m, 6 H, PCHCH3), 1.27,
1.19 (both dvt, N ) 14.5, 3J (HH) ) 7.3 Hz, 18 H each,
PCHCH3), -19.23 (br s, 1 H, IrH). 31P NMR (81.0 MHz, CD2-
Cl2): δ 1.7 (s).
1
was warmed for 2 h at 90 °C. Both the 31P and H NMR spectra
confirmed the quantitative conversion of 14 to 28 and the
formation of a mixture of 29 and 30 in the ratio of 1.80:1 (65%:
35%).37 After the solution was filtered with Al2O3 (neutral,
activity grade I), the filtrate was investigated by GC/MS to
reveal a ratio of 29 to 30 ) 2.2:1.
Gen er a tion of [Ir HCl2(dCP h 2)(P iP r 3)(SbiP r 3)] (27).
This compound was generated as described for 26 from 8 (32
P r epar ation of [Ir Cl(η1:η3-CP h dCP h CP h 2)(P iP r 3)] (31).
A solution of 8 (134 mg, 0.17 mmol) in pentane (15 mL) was
treated with diphenylacetylene (29 mg, 0.16 mmol) and stirred
for 3 h at room temperature. The initially clear dark red
solution became dulled, and a brown finely divided solid
started to precipitate. The formation of the solid was facilitated
by storing the suspension at -78 °C for 12 h. The mother liquor
1
mg, (0.04 mmol) and HCl. H NMR (200 MHz, C6D6): δ 7.65
(br m, 2 H, C6H5), 7.10, 6.87 (both m, 4 H each, C6H5), 2.50
(m, 3 H, PCHCH3), 2.27 (sept, 3J (HH) ) 7.3 Hz, 3 H,
SbCHCH3), 1.42, 1.34 (both d, 3J (HH) ) 7.3 Hz, 9 H each,
3
3
SbCHCH3), 1.24, 1.19 (both dd, J (PH) ) 14.0, J (HH) ) 7.3
Hz, 9 H each, PCHCH3), -18.78 (d, 2J (PH) ) 13.1 Hz, 1 H,
IrH). 31P NMR (81.0 MHz, C6D6): δ 4.3 (s).
(37) (a) Hernandez, D.; Larson, G. L. J . Org. Chem. 1984, 49, 4285-
4287. (b) Hixson, S. S.; Franke, L. A. J . Org. Chem. 1988, 53, 2706-
2711. (c) Araki, S.; Shimizu, T.; J ohar, P. S.; J in, S.-J .; Butsugan, Y.
J . Org. Chem. 1991, 56, 2538-2542. (d) Yamashita, T.; Shiomori, K.;
Yasuda, M.; Shima, K. Bull. Chem. Soc. J pn. 1991, 64, 366-374.
Reaction of tr a n s-[Ir Cl(dCP h 2)(P iP r 3)(SbiP r 3)] (8) with
Eth en e. A slow stream of ethene was passed for ca. 1 min
into a solution of 8 (30 mg, 0.04 mmol) in C6D6 (0.5 mL) at
room temperature. After the NMR tube was closed, the

Carbene Ir(I) and Ir(III) Complexes
Organometallics, Vol. 21, No. 12, 2002 2381
was decanted, and the residue was washed twice with 5 mL
portions of pentane (-20 °C) and dried: yield 91 mg (76%);
mp 124 °C dec. 1H NMR (200 MHz, CD2Cl2): δ 7.32, 6.98 (both
m, 16 H, C6H5), 6.57 (m, 2 H, C6H5), 6.08 (m, 1 H, C6H5), 3.78
(br s, 1 H, CH of π-bonded C6H5), 2.31 (m, 3 H, PCHCH3), 1.22,
1.03 (both m, 9 H each, PCHCH3). 13C NMR (50.3 MHz, CD2-
Cl2): δ 145.0 (d, J (PC) ) 4.9 Hz, ipso-C of C6H5), 143.8 (br),
140.4, 136.6 (both s, ipso-C of C6H5), 132.2 (br), 133.9, 131.3,
128.0, 127.7, 127.3, 127.0, 126.2, 123.1, 122.6 (all s, C6H5),
128.5, 114.3 (both s, CC6H5), 120.0, 109.7 (both br), 32.1 (s,
to be rotationally disordered over two independent positions
and refined anisotropically with restraints on interatomic
distances (DFIX) and on U(ij) (DELU, SIMU) with an occu-
pancy factor of 62:38; also one of the isopropyl groups of the
second stibane was found to be disordered and refined in the
same way with an occupancy factor of 79:21. The two highest
electron densities of 13 are less than 0.8 Å away from Cl1 and
Sb1. The four highest electron densities of 14 are all near that
of the iridium atom (<1.0 Å). The atoms of the cyclopentadienyl
ring in 17 were refined with restraints on U(ij) (DELU), and
the extinction coefficient was refined to 0.0037(2). Five of the
CF3 groups of the BArF anion in 24 were found rotationally
disordered and refined anisotropically with restraints on U(ij)
(DELU, SIMU) with the following occupancy factors: 86:14
(F1-F3), 55:45 (F4-F6), 58:42 (F10-F12), 51:49 (F13-F15),
74:26 (F19-F21). The metal-bonded hydrogen atom H100 of
24 was found in a differential Fourier synthesis and refined
isotropically with a fixed Ueq. The positions of all other
hydrogen atoms were calculated according to ideal geometry
and were refined by using the riding method, except for H100
of 24.
1
CH of π-bonded C6H5), 26.9 (d, J (PC) ) 29.4 Hz, PCHCH3),
20.7, 19.7 (both s, PCHCH3). 13C(1H) NMR (100.6 MHz, CD2-
Cl2), selected data: δ 32.1 (d, 1J (HC) ) 152.6 Hz, CH of
1
1
π-bonded C6H5], 26.9 (dd, J (HC) ) 128.4, J (PC) ) 29.4 Hz,
PCHCH3), 20.7, 19.7 (both q, 1J (HC) ) 127.2, PCHCH3). 31P
NMR (162.0 MHz, CD2Cl2): δ 26.1 (s). Anal. Calcd for C36H41
-
ClIrP: C, 59.04; H, 5.64. Found: C, 59.31; H, 6.18.
X-r a y Str u ctu r a l An a lysis of 13, 14, 17, a n d 24. Single
crystals of 13 and 14 were grown from acetone at -30 °C, those
of 17 from pentane at room temperature, and those of 24 from
ether/pentane at room temperature. The data were collected
on an Enraf-Nonius CAD4 diffractometer (13, 14, 17) or from
a shock-cooled crystal protected by an oil drop on a Stoe IPDS
diffractometer (24) using monochromated Mo KR radiation (λ
) 0.71 073 Å). Crystal data collection parameters are sum-
marized in Table 1. Intensity data were corrected by Lorentz
and polarization effects, and Lp and empirical absorption
corrections were applied for 13 (Ψ-scan method, minimum
transmission 89.46%), for 14 (Ψ-scan method, minimum
transmission 88.41%), and for 17 (Ψ-scan method, minimum
transmission 83.92%). The structure of 13 was solved by the
Patterson method (SHELXS-86), and the structures of 14, 17,
and 24 were solved by direct methods (SHELXS-86 for 17,
SHELXS-97 for 14, and 24).38 Atomic coordinates and aniso-
tropic displacement parameters were refined by full matrix
least-squares against Fo2 (SHELXL-93 for 13 and 17, SHELXL-
97 for 14 and 24).39 One of the stibane ligands of 13 was found
Ack n ow led gm en t . We thank the Deutsche For-
schungsgemeinschaft (Grant No. SFB 347) and the
Fonds der Chemischen Industrie for financial support,
the latter in particular for a Doktorandenstipendium
(to K.I.). Moreover, we gratefully acknowledge as-
sistance by R. Schedl and C. P. Kneis (DTA and
elemental analysis), F. Dadrich and Dr. G. Lange (mass
spectra), M.-L. Scha¨fer and Dr. W. Buchner (NMR
spectra), and BASF AG (gifts of chemicals).
Su p p or tin g In for m a tion Ava ila ble: Tables of data col-
lection parameters, bond lengths and angles, positional and
thermal parameters, and least-squares planes for 13, 14, 17,
and 24; data for these compounds are also given in CIF format.
This material is available free of charge via the Internet at
http://pubs.acs.org.
(38) Sheldrick, G. M. Acta Crystallogr., Sect. A 1990, 46, 467-473.
(39) Sheldrick, G. M. SHELXL-97, Program for Crystal Structure
Refinement; Universita¨t Go¨ttingen: Go¨ttingen, Germany, 1997.
OM020069A