Iridium and rhodium complexes containing fluorinated phenyl ligands and their transformation to η2-Benzyne complexes, including the parent benzyne complex IrCp*(PMe3)(C6H4)

Article abstract of DOI:10.1021/om0204787

The iridium and rhodium complexes containing fluorinated phenyl ligands were discussed. The crystal structures of these complexes were discussed and the 'through-space' nature of some coupling constants was confirmed. The transformation of these complexes

Full text of DOI:10.1021/om0204787

Organometallics 2002, 21, 4873-4885
4873
Ir id iu m a n d Rh od iu m Com p lexes Con ta in in g
F lu or in a ted P h en yl Liga n d s a n d Th eir Tr a n sfor m a tion
to η2-Ben zyn e Com p lexes, In clu d in g th e P a r en t Ben zyn e
Com p lex Ir Cp *(P Me3)(C6H4)
Russell P. Hughes,*,† Roman B. Laritchev,† Alex Williamson,†
Christopher D. Incarvito,‡ Lev N. Zakharov,‡ and Arnold L. Rheingold‡
Departments of Chemistry, 6128 Burke Laboratory, Dartmouth College,
Hanover, New Hampshire 03755, and University of Delaware, Newark, Delaware 19716
Received J une 19, 2002
Treatment of IrCp*(CO)2 (1) with C6F5I in benzene under reflux gives the oxidative addition
product IrCp*(C6F5)(CO)I (2). Treatment of 2 with PMe3 gives IrCp*(C6F5)(PMe3)I (3), which,
on treatment with AgO3SCF3 in the presence of traces of water, affords the cationic complex
[IrCp*(C6F5)(PMe3)(OH2)]O3SCF3 (4). Treatment of 4 with 1,8-bis(dimethylamino)naphtha-
lene (Proton Sponge) affords the hydride complex IrCp*(C6F5)(PMe3)H (5), which reacts with
n-BuLi to give the tetrafluorobenzyne complex IrCp*(η2-C6F4)(PMe3) (6) in high yield.
Similarly, treatment of RhCp*(CO)2 (7) with C6F5I in toluene at 80 °C affords a pentafluo-
rophenyl complex of rhodium, RhCp*(C6F5)(CO)I (8). Treatment of 8 with PMe3 at room
temperature affords RhCp*(C6F5)(PMe3)I (9), which reacts with NaBH4 to give RhCp*(C6F5)-
(PMe3)H (10). Treatment of 10 with n-BuLi gives the rhodium tetrafluorobenzyne complex
RhCp*(η2-C6F4)(PMe3) (11) in high yield. Treatment of IrCp*(CO)2 with 1-fluoro-2-iodoben-
zene in toluene under reflux gives the oxidative addition product IrCp*(2-C6FH4)(CO)I (12),
which is converted to IrCp*(2-C6FH4)(PMe3)I (13) by treatment with PMe3. Treatment of 13
with NaBH4 gives IrCp*(2-C6FH4)(PMe3)H (14), which, on treatment with n-BuLi, is
converted to a mixture of the nonfluorinated benzyne complex IrCp*(η2-C6H4)(PMe3) (15)
and the phenyl butyl complex IrCp*(C6H5)(n-Bu)(PMe3) (16). Treatment of Ir(C5Me4Et)(CO)2
with 2,3,4,5-tetrafluorobenzoyl chloride at 110 °C under reflux gives the oxidative addition
product Ir(C5Me4Et)(2,3,4,5-C6F4H)(CO)Cl (17), which on treatment with PMe3 gives Ir(C5-
Me4Et)(C6F4H)(PMe3)Cl (18). Using analogous methodology this was converted to the
unsymmetrical trifluorobenzyne complex Ir(C5Me4Et)(η2-3,4,5-C6F3H)(PMe3) (21), in which
the benzyne ligand is shown to be stereochemically rigid on the NMR time scale, allowing
a minimum value for the rotational barrier about the iridium-benzyne bond to be estimated
at 20.3 kcal mol-1. The crystal structures of complexes 2, 3, 9, 11-15, 17, and 18 are reported
1
and discussed, and the “through-space” nature of some coupling constants between 31P, H,
and 19F is confirmed using heteronuclear Overhauser enhancement (HOESY) NMR
spectroscopy.
In tr od u ction
of an aryl halide to a metal complex with a cyclopen-
tadienyl ligand.8 Examples of oxidative addition reac-
tions of perfluorinated aryl halides to transition metals
seem to be restricted to reactions with transition-metal
powders or atoms9-11 and to examples of oxidative
addition of hexafluorobenzene to metal complexes, in
which C6F6 undergoes cleavage of a C-F bond to
produce pentafluorophenyl fluoride complexes.8,12,13
Many examples of η2-benzyne complexes have been
reported in the literature14-16 and include examples
There are many examples of oxidative addition reac-
tions involving aryl halides and low-valent metal
complexes.1-7 However, to the best of our knowledge,
there is only one example involving oxidative addition
† Dartmouth College.
‡ University of Delaware.
(1) Gallasch, D. P.; Tiekink, E. R. T.; Rendina, L. M. Organometallics
2001, 20, 3373-3382.
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K. Organometallics 2001, 20, 2704-2715.
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H.; Milstein, D. J . Am. Chem. Soc. 2000, 122, 7723-7734.
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F. J . Organomet. Chem. 2000, 601, 201-210.
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R. N. J . Am. Chem. Soc. 1993, 115, 1429-1440.
10.1021/om0204787 CCC: $22.00 © 2002 American Chemical Society
Publication on Web 10/04/2002

4874 Organometallics, Vol. 21, No. 22, 2002
Hughes et al.
from early17-20 and late15,21-23 transition metals. While
benzyne complexes of early transition metals,17,18,20 and
of ruthenium,23 can be synthesized using thermally
induced â-elimination of methane or benzene from aryl
methyl and diaryl complexes, respectively, this method
is not useful for group 10 complexes, due to competing
reductive elimination of the σ-bound carbon ligands.
Instead, benzyne complexes of nickel and platinum have
been synthesized by reduction of preformed (2-haloaryl)-
metal(II) halide complexes.15,21,22 Benzyne complexes of
both ruthenium and nickel have been shown to undergo
a variety of insertion reactions with unsaturated mol-
ecules and addition reactions with electrophiles.15,21-23
In a preliminary communication, we described the
synthesis of the first example of an η2-tetrafluoroben-
zyne transition metal complex using a route different
from those previously described.24 Here we provide a
detailed account of this work, with a full examination
of the preparations and properties of the precursor
compounds and the fluorinated benzyne product. Exten-
sions to the syntheses and properties of an analogous
rhodium tetrafluorobenzyne complex and to an iridium
complex of the parent hydrocarbon benzyne ligand are
also presented.
the reaction conditions to ensure good yields of 2. When
hexane is used as the reaction solvent, reflux conditions
provide negligible conversion to the desired product.
Refluxing toluene leads to formation of a large amount
of IrCp*I2(CO), together with other unidentified decom-
position products. Best results are achieved when a
benzene solution is heated under gentle reflux for 40 h.
The product, after recrystallization, contains about 10%
IrCp*I2(CO) together with a small amount of unidenti-
fied decomposition product, but complex 2 is easily
purified by column chromatography. The 19F NMR
spectrum of this compound shows broad signals for the
ortho and meta fluorine atoms on the pentafluorophenyl
ring. We attribute this to restricted rotation about the
Ir-C bond on the NMR time scale, a phenomenon that
has been observed previously in transition metal pen-
tafluorophenyl complexes8,13,28-34 and has been at-
tributed to combinations of steric hindrance from other
ligands and high electron density on the metal, resulting
in stronger dπ-pπ interactions.
Resu lts a n d Discu ssion
The iridium(I) complex IrCp*(CO)2 (1) readily under-
goes oxidative addition reactions with a variety of
fluorinated alkyl iodides at room temperature.25-27 In
Treatment of complex 2 with PMe3 in refluxing
toluene gives the trimethylphosphine complex IrCp*-
(C6F5)(PMe3)I (3). The 19F NMR spectrum of 3 comprises
contrast, more vigorous conditions are required for the
analogous oxidative addition reaction with C6F5I to form
IrCp*(C6F5)(CO)I (2). Careful attention must be paid to
(14) Bennett, M. A.; Schwemlein, H. P. Angew. Chem., Int. Ed. Engl.
1989, 28, 1296-1320.
five distinct resonances, indicating that rotation about
the Ir-C6F5 bond is slow on the NMR time scale. It is
interesting to note that, in this complex, the protons of
the PMe3 ligand couple with only one of the ortho
(15) Bennett, M. A.; Wenger, E. Chem. Ber./ Recl. 1997, 130, 1029-
1042.
(16) J ones, W. M.; Klosin, J . Adv. Organomet. Chem. 1998, 42, 147-
221.
(17) McLain, S. J .; Schrock, R. R.; Sharp, P. R.; Churchill, M. R.;
Youngs, W. J . J . Am. Chem. Soc. 1979, 101, 263-265.
(18) Buchwald, S. L.; Watson, B. T.; Huffman, J . C. J . Am. Chem.
Soc. 1986, 108, 7411-7413.
(19) Buijink, J . K. F.; Kloetstra, K. R.; Meetsma, A.; Teuben, J . H.;
Smeets, W. J . J .; Spek, A. L. Organometallics 1996, 15, 2523-2533.
(20) Wada, K.; Pamplin, C. B.; Legzdins, P. J . Am. Chem. Soc. 2002,
124, 9680-9681.
(21) Bennett, M. A.; Hambley, T. W.; Roberts, N. K.; Robertson, G.
B. Organometallics 1985, 4, 1992-2000.
fluorine atoms of the pentafluorophenyl ligand (6J HF
)
1.5 Hz). This is a “six-bond” coupling constant and is
likely to contain a strong component of through-space,
as opposed to through-bond, coupling. Remote H-F
coupling of ortho fluorines with protons has been seen
in other C6F5 complexes and has also been attributed
(28) Leblanc, J . C.; Moise, C. Org. Magn. Reson. 1980, 14, 157-
160.
(29) Casares, J . A.; Espinet, P.; Martinez-Ilarduya, J . M.; Lin, Y.-
S. Organometallics 1997, 16, 770-779.
(30) Uson, R.; Fornies, J .; Espinet, P.; Lalinde, E.; J ones, P. G.;
Sheldrick, G. M. J . Chem. Soc., Dalton Trans. 1982, 12, 2389-2395.
(31) Corradi, M. M.; Pindado, G. J .; Sarsfield, M. J .; Thornton-Pett,
M.; Bochmann, M. Organomet. 2000, 19, 1150-1159.
(32) Torre, F. G. d. l.; Hoz, A. d. l.; J alon, F. A.; Manzano, B. R.;
Rodriguez, A. M.; Elguero, J .; Martinez-Ripoll, M. Inorg. Chem. 2000,
39, 1152-1162.
(22) Bennett, M. A.; Dirnberger, T.; Hockless, D. C. R.; Wenger, E.;
Willis, A. C. J . Chem. Soc., Dalton Trans. 1998, 271-278.
(23) Hartwig, J . F.; Bergman, R. G.; Andersen, R. A. J . Am. Chem.
Soc. 1991, 113, 3404-3418.
(24) Hughes, R. P.; Williamson, A.; Sommer, R. D.; Rheingold, A.
L. J . Am. Chem. Soc. 2001, 123, 7443-7444.
(25) Hughes, R. P.; Smith, J . M. J . Am. Chem. Soc. 1999, 121, 6084-
6085.
(26) Hughes, R. P.; Smith, J . M.; Liable-Sands, L. M.; Concolino, T.
E.; Lam, K.-C.; Incarvito, C.; Rheingold, A. L. J . Chem. Soc., Dalton
Trans. 2000, 873-879.
(27) Hughes, R. P.; Lindner, D. C.; Smith, J . M.; Zhang, D.; Incarvito,
C. D.; Lam, K.-C.; Liable-Sands, L. M.; Sommer, R. D.; Rheingold, A.
L. J . Chem. Soc., Dalton Trans. 2001, 2270-2278.
(33) Bennett, R. L.; Bruce, M. I.; Gardner, R. C. F. J . Chem. Soc.,
Dalton Trans. 1973, 2653-2657.
(34) Crocker, C.; Goodfellow, R. J .; Gimeno, J .; Uson, R. J . Chem.
Soc., Dalton Trans. 1977, 1448-1452.

Ir and Rh Complexes with Fluorinated Ph Ligands
Organometallics, Vol. 21, No. 22, 2002 4875
to through-space coupling.28,33 Clearly, the favored
conformation for the C6F5 ligand orients one of the ortho
fluorine atoms closer to the PMe3 ligand than the other
ortho fluorine atom, as borne out by the solid-state
structure (see below). The 31P{1H} NMR spectrum of 3
appears as a doublet (4J PF ) 19 Hz) arising from
coupling of the phosphorus atom with the same ortho
fluorine atom. But which fluorine atom is responsible
for this coupling: the proximal ortho fluorine, or its
distal analogue? Each is a candidate for six-bond
coupling. 1H/19F HOESY experiments have been shown
to be very useful indicators of ion-pair proximity be-
tween protons and fluorine atoms in organometallic
salts.35 An analogous experiment for 3 shows a signifi-
cant cross-peak between the hydrogen atoms of the
PMe3 ligand and the same ortho fluorine atom that
exhibits the F-P coupling, but no cross-peak to the
other ortho fluorine atom. The HOESY experiment also
shows significant cross-peaks between both ortho fluo-
rine atoms and the Cp* ligand protons. These data are
consistent with a pentafluorophenyl ring conformation
similar to that observed in the solid state (see below),
and as shown in the drawing. Since the HOESY cross-
peaks are dependent only on distance, this provides
confirmation that the J coupling between 31P and 19F
in this compound, and presumably in other analogues,
occurs selectively to the proximal ortho fluorine.
described for analogous fluoroalkyl complexes contain-
ing water ligands.27,36 A combination of both pathways
may be more likely, given the precedent for each, and
we have not attempted to distinguish between them.
We have shown previously that 1,8-bis(dimethylami-
no)naphthalene (Proton Sponge) can behave as a hy-
dride donor, and we have used this extensively in the
preparation of Group 9 metal (fluoroalkyl)hydride com-
plexes from cationic precursors.37 In the same way,
complex 4a reacts with proton sponge in toluene at room
temperature to give the hydride complex IrCp*(C6F5)-
(PMe3)H (5). A slightly less pure sample of 5 can be
obtained by direct reaction of 3 and NaBH4 in refluxing
2-propanol, but in this case it is difficult to remove the
last traces of solvent from the product, and the alcohol
interferes with subsequent chemistry. This complex has
been reported previously by Bergman38 from the reac-
tion of [IrCp*(PMe3)H]-Li+ with C6F6. The 19F NMR
spectrum of 5 also contains five separate fluorine
resonances, indicating slow rotation about the Ir-C6F5
bond. While the 31P{1H} NMR spectrum of this com-
pound was initially reported as a singlet,38 we observe
Treatment of complex 3 with AgO3SCF3 in toluene
and subsequent exposure to moist air affords [IrCp*-
1
(C6F5)(PMe3)(OH2)]O3SCF3 (4a ). The 19F, H, and 31P
4
it as a doublet of doublets (4J PF ) 6.8 Hz, J PF ) 2.9
Hz), due to inequivalent coupling to each ortho fluorine
atom of the pentafluorophenyl ligand. It is interesting
that the molecular structure of a related aryl hydrido
complex (see below) shows a conformation of the aryl
ligand different from that observed when the adjacent
ligand is more bulky than H, in which the two ortho
positions are closer to phosphorus, perhaps explaining
the less selective J values compared to those of other
complexes.
NMR spectra of 4a in CD2Cl2 are broad at room
temperature. When the temperature is lowered to -40
°C, the 19F NMR spectrum decoalesces into two sets of
resonances, which we attribute to [IrCp*(C6F5)(PMe3)-
(OH2)]O3SCF3 (4a ) and IrCp*(C6F5)(PMe3)O3SCF3 (4b).
The ratio of 4a and 4b is variable and depends on the
moisture content of the CD2Cl2 (the relative concentra-
tion of 4b being higher when air is excluded from the
NMR tube). At -40 °C, the 19F resonances of 4a are
sharp and exist as five individual resonances, showing
that the Ir-C6F5 rotation is slow at this temperature.
However, the resonances due to the ortho and meta
fluorines of 4b are broad at this temperature, but on
further cooling to -75 °C, the spectrum sharpens into
five individual resonances. These observations can be
explained either by slowing of Ir-C6F5 rotation as the
temperature is lowered, as observed in other C6F5
complexes,8,13,29 or to a situation in which the C6F5 ring
is conformationally rigid, with rapid dissociation of
water, inversion at the metal, and reassociation of water
being the process resulting in exchange of fluorine
resonances. A similar phenomenon has already been
Treatment of complex 5 with 10 equiv of a solution of
n-BuLi in hexanes effects slow conversion to the tet-
rafluorobenzyne complex IrCp*(η2-C6F4)(PMe3) (6). The
excess of lithiation reagent is used to give a convenient
reaction time. We have proposed24 that the mechanism
of the reaction involves deprotonation of the Ir-H
(36) Hughes, R. P.; Lindner, D. C.; Rheingold, A. L.; Liable-Sands,
L. M. J . Am. Chem. Soc. 1997, 119, 11544-11545.
(37) Hughes, R. P.; Kovacik, I.; Lindner, D. C.; Smith, J . M.;
Willemsen, S.; Zhang, D.; Guzei, I. A.; Rheingold, A. L. Organometallics
2001, 20, 3190-3197.
(38) Peterson, T. H.; Golden, J . T.; Bergman, R. G. Organometallics
1999, 18, 2005-2020.
(35) Zuccaccia, C.; Bellachioma, G.; Cardaci, G.; Macchioni, A. J .
Am. Chem. Soc. 2001, 123, 11020-11028.

4876 Organometallics, Vol. 21, No. 22, 2002
Hughes et al.
bond,38,39 followed by elimination of an ortho fluorine
atom and formation of LiF. The 13C{1H} NMR spectrum
of 6 shows a multiplet at δ 84.2 ppm corresponding to
the coordinated carbon atoms of the benzyne ligand.
This is a very high field chemical shift relative to those
of previously reported benzyne complexes, which fall in
the range 141.8-230.5 ppm.16 The ortho and meta
carbon atoms on the benzyne ligand resonate as dou-
blets at δ 135.3 and 142.8 ppm (1J CF ) 253 Hz).
complex of iridium using the same method. Treatment
of 1 with 1-fluoro-2-iodobenzene in toluene under reflux
affords the monofluorophenyl complex IrCp*(2-C6FH4)-
(CO)I (12). Treatment of this complex with PMe3 leads
to formation of IrCp*(2-C6FH4)(PMe3)I (13). Complex 13
To confirm the generality of this synthetic approach
to tetrafluorobenzyne complexes, we explored the chem-
istry of analogous pentafluorophenyl complexes of rhod-
ium. Treatment of RhCp*(CO)2 (7) with C6F5I in toluene
in an oil bath at 80 °C affords the oxidative addition
product RhCp*(C6F5)(CO)I (8), which is generally con-
taminated with a small amount of RhCp*I2(CO). Puri-
fication is easily achieved by column chromatography.
Like the iridium analogue, the 19F NMR spectrum
exhibits broad peaks corresponding to the ortho and
meta fluorines of the pentafluorophenyl ring. Treatment
of 7 with PMe3 in toluene at room temperature cleanly
produces the trimethylphosphine complex RhCp*(C6F5)-
(PMe3)I (9). The 19F NMR spectrum of this complex, like
its iridium analogue, shows five individual resonances
corresponding to each of the fluorine atoms of the
pentafluorophenyl ring. The 31P{1H} NMR spectrum
exists as a doublet of doublets with a phosphorus-
rhodium coupling constant of 144.3 Hz and a single
phosphorus-fluorine coupling constant of 25.3 Hz, due
to coupling with the proximal ortho fluorine.
Treatment of 9 with NaBH4 in THF at 50 °C for 16 h
affords the highly air-sensitive compound RhCp*(C6F5)-
(PMe3)H (10). This compound was previously reported
by J ones,40 who obtained it by heating a mixture of
RhCp*(PMe3)H2 and C6F6 at 85 °C in d5-pyridine. As
observed in the 1H NMR spectrum of the iridium
analogue, the hydride ligand of 10 couples with both of
the inequivalent ortho fluorine atoms. However, in this
case the coupling constants are equivalent, forming a
triplet pattern (4J PF ) 9.3 Hz), so it not possible to
distinguish between a static structure, in which both
coupling constants are fortuitously equal, and a struc-
ture containing a rapidly rotating aryl ring, in which
they are averaged. To obtain a pure sample of the
required rhodium-benzyne complex, it is necessary to
treat a freshly synthesized sample of 10 with 1.3 equiv
of n-BuLi at -78 °C. After this mixture is stirred for 1
h at room temperature, conversion to RhCp*(η2-C6F4)-
(PMe3) (11) is complete and clean. This reaction rate is
in contrast to the much slower reaction of the Ir
analogue (vide supra), which requires a large excess of
BuLi to proceed at a convenient rate. Complex 11 is air-
sensitive in solution and decomposes in air in the solid
state over a few days. The 19F NMR spectrum shows
the expected AA′XX′ coupling pattern with extra rhod-
ium coupling observed for the two ortho fluorines (4J FRh
) 4.5 Hz). The structure was confirmed by X-ray
diffraction (see below).
is converted to IrCp*(2-C6FH4)(PMe3)H (14) by reaction
with NaBH4 in EtOH at 70 °C. It is not possible to
deduce from the room-temperature NMR spectra of 13
whether there is facile or restricted rotation about the
Ir-C6FH4 bond on the NMR time scale, as only a single
fluorine resonance is observed, showing a coupling (4J FP
) 10.5 Hz) to phosphorus. However, in complex 14 at
room temperature, the 1H, 19F, and 31P NMR spectra
are broad and decoalesce at -60 °C into two sets of
resonances in a ratio of 2.8:1, which leads us to deduce
that the Ir-C6FH4 rotation is relatively fast on the NMR
time scale at room temperature. The major rotamer
shows a coupling (4J FP ) 4.4 Hz) between the single F
and P, indicating it to be the proximal isomer; the minor
(distal) rotamer shows no such coupling. Therefore, in
a sterically more hindered complex such as 13, we
conclude that rotation about the Ir-C6FH4 bond is slow
on the NMR time scale at room temperature. Treatment
of 14 with 10 equiv of n-BuLi and stirring for 4 h at
room temperature leads, after workup, to formation of
the benzyne complex IrCp*(η2-C6H4)(PMe3) (15) together
with small amounts of starting material and the phenyl
n-butyl complex IrCp*(C6H5)(n-Bu)(PMe3) (16). The
relative amount of 16 increases if the reaction is allowed
to proceed for longer periods or is conducted at a higher
temperature. The benzyne complex 15 is separated by
slow evaporation of a hexane solution to produce large
transparent crystals. The butyl complex 16 can be
separated by column chromatography (silica, hexanes)
and exists as a transparent oil. For complex 15, the
aromatic region of the phosphorus-decoupled proton
NMR spectrum shows the expected AA′XX′ coupling
pattern. The 13C NMR spectrum shows a doublet at
To explore the generality of the synthetic method for
formation of nonfluorinated η2-benzyne complexes, we
approached the synthesis of a nonfluorinated benzyne
(39) Golden, J . T.; Peterson, T. H.; Holland, P. L.; Bergman, R. G.;
Andersen, R. A. J . Am. Chem. Soc. 1998, 120, 223-224.
(40) Edelbach, B. L.; J ones, W. D. J . Am. Chem. Soc. 1997, 119,
7734-7742.

Ir and Rh Complexes with Fluorinated Ph Ligands
Organometallics, Vol. 21, No. 22, 2002 4877
107.9 ppm (2J CP ) 9.2 Hz) which corresponds to the ipso
carbon atoms of the benzyne ligand. This is downfield
from the corresponding value for the tetrafluorobenzyne
analogue (6) by 23.7 ppm but still significantly upfield
from those of other reported benzyne complexes. The
ortho and meta carbon atoms of the benzyne ligand
resonate as singlets at 116.3 and 126.9 ppm, both
significantly upfield from those in the tetrafluoro-
benzyne analogue (6).
Et)(CO-2,3,4,5-C6F4H)(CO)Cl, which slowly decarbony-
lates on heating. Indeed, NMR examinations of aliquots
The rotational barrier about a metal-benzyne bond
in mononuclear η2-benzyne complexes has previously
been addressed. The first report, by Schrock, of a
structurally characterized mononuclear benzyne com-
plex, Cp*Ta(Me)2(C6H4),17 states that the benzyne ligand
is rapidly rotating in solution. A later report by Wilkin-
son41 indicates that, for the complex [Re(η2-C6H3Me)-
(C6H4Me)2(PMe3)2]O3SCF3, rotation about the Re-
benzyne bond is slow on the NMR time scale up to 100
°C. Also, Bennett21 has shown that, for the complex
Ni(η2-C6H4)(Cy2PCH2CH2PCy2), rotation about the
Ni-benzyne bond is slow on the NMR time scale at
room temperature.
during the reaction show initial formation of a transient
C6F4H-containing complex, which slowly converts to the
desired compound 17, but no attempts were made to
isolate this intermediate. Treatment of 17 with PMe3
produces Ir(C5Me4Et)(2,3,4,5-C6F4H)(PMe3)Cl (18), also
The IrCp*(PMe3) fragment is isolobal with CH2,42 and
a relatively high barrier to rotation of the coordinated
alkene or alkyne is expected.43 However, to examine the
rotational barrier about the Ir-benzyne bond in an
iridium benzyne complex of the type IrCp*(PMe3)(η2-
benzyne) in which each side of the benzyne ligand is
related by a symmetry plane, it is necessary to introduce
some asymmetry into the molecule to provide inequiva-
lent sites that are exchanged by benzyne ligand rotation.
Replacing one of the fluorine substituents on the ben-
zyne ligand by a different atom breaks the symmetry,
and restricted rotation about the Ir-benzyne bond
makes the metal a stereocenter whose configuration is
inverted by benzyne rotation. An indirect reporter group
is incorporated using an ethyltetramethylcyclopentadi-
enyl ligand; the stereocenter at Ir generates four C-Me
environments and diastereotopic protons of the CH2
group, and rapid inversion by virtue of benzyne rotation
would cause pairwise exchange of C-Me groups and
remove the diastereotopic inequivalence of the CH2
protons. We chose as our target molecule Ir(C5Me4Et)-
(η2-3,4,5-C6F3H)(PMe3).
Synthesis of Ir(C5Me4Et)(CO)2 was achieved from [Ir-
(C5Me4Et)Cl2]2 and Fe3(CO)12, using the method devel-
oped by Maitlis for the Cp* analogue.44 Due to the
commercial unavailability of any isomers of iodotet-
rafluorobenzene, we opted to attempt oxidative addition
of 2,3,4,5-tetrafluorobenzoyl chloride to this dicarbonyl
precursor to give a benzoyl complex that could be
decarbonylated to give the required aryl group. To our
delight, heating a mixture of 2,3,4,5-tetrafluorobenzoyl
chloride and Ir(C5Me4Et)(CO)2 at 110 °C for 48 h
produces Ir(C5Me4Et)(2,3,4,5-C6F4H)(CO)Cl (17), which
was purified by column chromatography and character-
ized crystallographically (see below). Formation of 17
presumably proceeds via the benzoyl complex Ir(C5Me4-
crystallographically characterized, which was then con-
verted to [Ir(C5Me4Et)(2,3,4,5-C6F4H)(PMe3)(OH2)]O3-
SCF3 (19) by treatment with AgO3SCF3. Treatment of
19 with Proton Sponge affords Ir(C5Me4Et)(2,3,4,5-
C6F4H)(PMe3)H (20), which was converted to the desired
benzyne complex Ir(C5Me4Et)(η2-3,4,5-C6F3H)(PMe3) (21)
by treatment with 10 equiv of n-BuLi. At room temper-
1
ature, the H NMR spectrum of 21 shows that one of
the sets of ring-bound methyl substituents on the C5-
Me4Et ligand is split into two signals, indicating the
presence of a stereocenter at the metal. Consequently,
at room temperature the rotation about the Ir-benzyne
bond is slow on the NMR time scale. Heating to 100 °C
in d10-xylene does not produce any sign of coalescence,
and therefore, a minimum barrier to rotation of 20.3
kcal mol-1 can be calculated.
Cr ysta l Str u ctu r es. (a ) Flu or in a ted P h en yl Com -
p lexes. ORTEP diagrams of the molecular structures
of the fluorinated phenyl complexes 2, 3, 9, 12-14, 17,
and 18 are presented in Figures 1-8, respectively, and
details of the crystallographic determinations are com-
piled in Table 1. The atom-numbering scheme for each
complex is self-consistent, and selected bond distances
and angles are assembled in Table 2. The hydride
complex 14 contains two molecules in the asymmetric
unit, but the hydride ligand was not found. In addition,
the fluorine atom in 14 is disordered between C(2) and
C(6), with the major occupancy site (F(21)) at C(2); this
is the structure illustrated for each molecule. Each of
the eight structures shows the expected three-legged
(41) Arnold, J .; Wilkinson, G.; Hussain, B.; Hursthouse, M. B.
Organometallics 1989, 8, 415-420.
(42) Hoffmann, R. Angew. Chem., Int. Ed. Engl. 1982, 10, 711-724.
(43) Albright, T. A.; Hoffmann, R.; Thibeault, J . C.; Thorn, D. L. J .
Am. Chem. Soc. 1979, 101, 3801-3812.
(44) Kang, J . W.; Moseley, K.; Maitlis, P. M. J . Am. Chem. Soc. 1969,
91, 5970-5977.

4878 Organometallics, Vol. 21, No. 22, 2002
Hughes et al.
F igu r e 4. ORTEP diagram of the non-hydrogen atoms of
compound 12, with thermal ellipsoids shown at the 30%
level.
F igu r e 1. ORTEP diagram of the non-hydrogen atoms of
compound 2, with thermal ellipsoids shown at the 30%
level.
F igu r e 2. ORTEP diagram of the non-hydrogen atoms of
compound 3, with thermal ellipsoids shown at the 30%
level.
F igu r e 5. ORTEP diagram of the non-hydrogen atoms of
compound 13, with thermal ellipsoids shown at the 30%
level.
F igu r e 3. ORTEP diagram of the non-hydrogen atoms of
compound 9, with thermal ellipsoids shown at the 30%
level.
F igu r e 6. ORTEP diagram of the non-hydrogen atoms of
one of the crystallographically independent molecules of
compound 14, with thermal ellipsoids shown at the 30%
level.
piano-stool geometry. Figure 9 contains projections of
these structures, with only the ring centroid included;
each projection is viewed down the Ir-C(1) bond, with
the M-Ct(01) vector perpendicular. The angles between
the ligands comprising the legs of the piano stool are
all close to 90°, while those between Ct(01) and the other
ligands are much more obtuse and lie in the 120-130°
range. The M-C(1) distances are not significantly

Ir and Rh Complexes with Fluorinated Ph Ligands
Organometallics, Vol. 21, No. 22, 2002 4879
F igu r e 7. ORTEP diagram of the non-hydrogen atoms of
compound 17, with thermal ellipsoids shown at the 30%
level.
F igu r e 8. ORTEP diagram of the non-hydrogen atoms of
compound 18, with thermal ellipsoids shown at the 30%
level.
different in any of the compounds, except for hydride
complex 14, in which they are slightly smaller (Table
2). The effect of replacing Ir by Rh is insignificant, as
judged by metric parameters for compounds 3 and 9.
The effect of replacing a CO ligand with a PMe3 ligand
is a general increase in the bond angles between the
monodentate ligands, as judged by data for 2 and 3.
Although the M-C(1) distances to the phenyl rings
are statistically identical, there are significant differ-
ences in the orientation of the phenyl ring with respect
to the rest of the molecule, as shown in Figure 9. These
structural differences are quantified as the torsion
angles Ct(01)-M-C(1)-C(2) and Ct(01)-M-C(1)-C(6)
and the angle M-C(1)-C(4), as presented in Table 2.
In the carbonyl iodo complexes 2 and 12 the aryl rings
are canted toward the CO ligand and away from the
iodide. In 12 this canting is less, probably due in part
to the absence of a fluorine on C(6), with consequently
less steric interaction with I(1). When the iodide is
replaced by the smaller chloride ligand, and without a
fluorine on C(6) as in 17, the aryl ring lies almost
perpendicular to the M-Ct(01) vector. Comparison of
2 and 3 illustrates the effect of replacing CO with PMe3;
the additional repulsion between PMe3 and F(21) results

4880 Organometallics, Vol. 21, No. 22, 2002
Ta ble 2. Selected Dista n ces (Å) a n d An gles (d eg) in F lu or op h en yl Com p lexes
Hughes et al.
2
12
17
3
9
18
13
14b
M-C(1)
M-P(1)
M-C(20)
M-X
2.093(5)
2.086(3)
2.085(3)
2.086(3)
2.079(3)
2.075(2)
2.088(6)
2.055(8), 2.068(8)
2.2899(8) 2.2962(10) 2.2839(7) 2.2783(19) 2.234(2), 2.231(2)
1.880(6)
1.916(5)
1.878(3)
2.7010(4) 2.6876(3) 2.4000(7) 2.7320(3) 2.7234(4)
1.864(5) 1.882(5) 1.858(5) 1.856(5) 1.850(5)
2.4120(6) 2.7257(6)
1.845(5) 1.853(5)
M-Ct(01)a
1.893(5), 1.890(5)
Ct(01)-M-C(1)
Ct(01)-M-P(1)
Ct(01)-M-C(20)
Ct(01)-M-X
C(1)-M-P(1)
C(1)-M-C(20)
C(1)-M-X
125.59(5) 121.61(5) 124.13(5) 121.26(5) 120.81(5)
129.53(5) 128.81(5)
129.58(6) 130.40(5) 129.37(5)
124.84(5) 123.02(5)
131.70(5) 130.56(5)
126.09(5), 125.17(5)
133.26(5), 133.00(5)
122.27(4) 122.90(5) 121.51(5) 122.36(5) 122.31(5)
123.42(5) 121.65(5)
93.90(8)
94.21(10)
90.69(7)
92.02(18)
90.0(2), 90.9(2)
90.03(6)
91.10(5)
91.22(14) 90.08(12)
89.65(9) 88.65(8)
92.87(8)
86.74(2)
94.10(10)
87.05(3)
88.63(7)
84.14(2)
90.48(18)
87.83(5)
P(1)-M-X
C(20)-M-X
86.29(6)
176.8(6)
89.91(11) 91.89(9)
M-C(1)-C(4)
173.4(5)
96.6(5)
75.7(6)
178.0(5)
93.2(5)
84.2(5)
169.1(6)
91.6(5)
73.9(5)
169.1(6)
91.5(5)
74.5(5)
176.1(5)
75.4(5)
99.3(5)
170.5(5)
88.7(5)
79.8(5)
177.9(5), 176.2(5)
80.8(5), 84.2(5)
94.2(6), 90.7(6)
Ct(01)-M-C(1)-C(2)c 103.8(6)
Ct(01)-M-C(1)-C(6)c 76.2(6)
a
b
Ct(01) ) centroid of [C(7) - C(11)]. Two independent molecules in asymmetric unit. c Torsion angle.
in a dramatic reduction in the Ct(01)-M-C(1)-C(2)
angle, from 104° to 76°, but without a significant
reduction in the Ct(01)-M-C(1)-C(6) angle, which
remains at 76°. The distortion is accommodated not by
a simple rotation of the aryl ring about the M-C(1)
bond, as might be expected, but instead by a distortion
of the whole aryl ring, up toward the Cp*, as shown in
Figure 9, and quantified by the contraction of the
M-C(1)-C(4) angle from 177° to 173°. An almost
identical distortion is observed in the structure of 9. In
the absence of a fluorine on C(6), as in 18, the aryl ring
can cant away from PMe3 toward iodide, but there is
still a analogous out-of-plane distortion of the aryl ring
toward Cp*. In the chloro and hydrido complexes 18 and
14, reduced steric interaction between C(6), which does
not bear a fluorine, and the adjacent Cl or H ligands
leads to structures in which the aryl ring cants toward
the smaller ligand and shows a much smaller out-of-
plane distortion.
(b) Ben zyn e Com p lexes. The structure of the iri-
dium complex of tetrafluorobenzyne 6 was reported in
our original communication,24 and those of the rhodium
analogue 11 and the iridium benzyne complex 15 are
described here. ORTEP plots are provided in Figures
10 and 11; the atom-numbering system is different from
that of the previously described phenyl complexes (vide
supra) but, to facilitate comparisons, is identical with
that already published for 6.24 The rhodium complex 11
exists as two independent molecules in the asymmetric
unit, thereby providing two independent sets of metric
parameters, but complex 15, containing the parent
benzyne ligand, lies on a crystallographic plane of
symmetry, reducing the number of independent param-
eters. Details of the crystallographic determinations are
provided in Table 1, and selected bond lengths and
angles for 11 and 15 along with comparison values for
6 are provided in Table 3.
bond. In structure 6, the phosphine adopts a conforma-
tion in which the corresponding P-C(17) bond eclipses
the Ir-C(12) bond less, while in 11 the crystallographi-
cally imposed symmetry makes this point moot. Con-
sequently, it seems likely that significant differences in
M-C bond lengths in 11 are the result of steric effects
with the phosphine ligand.
Although the M-C distances are not significantly
different between 6 and 15, one effect of fluorination in
the benzyne ligand appears to be a slight decrease in
the M-P(1) distance and a slight increase in the M-
Ct(01) distance in 15, compared to those in 6, and also
in rhodium analogue 11. These crystallographic differ-
ences are slight and are not likely to be chemically
significant. In our communication concerning the struc-
ture of 6, we noted the different pattern of bond lengths
around the tetrafluorobenzyne ring in comparison to
those of other benzyne complexes,24 with C(14)-C(15)
being the shortest bond. The pattern of bond distances
around the hydrocarbon benzyne ligand in 15 and in
the tetrafluorobenzyne ligands of the two independent
molecules of 11 are not as significantly different as those
in 6. Moreover, the distance between the coordinated
benzyne carbon atoms C(11)-C(12) is significantly
longer in 6 than in either the hydrocarbon complex 15
or the fluorocarbon analogue 11, which are insignifi-
cantly different from one another. The interpretation
of bond distances in these compounds in terms of effects
induced by fluorine seems to have been premature.
The temptation to overinterpret metric parameters
obtained from crystallographic studies of these com-
pounds is illustrated by a comparison of the planarity
of the M-benzyne system in each compound, as quanti-
fied by the dihedral angle between the least-squares
planes M-C(11)-C(12) and C(11) through C(16). For
complex 6 this angle is 171.5(4)°, significantly different
from that of 175.6(4)° in 15. However, the two indepen-
dent molecules of compound 11 show values of 170.4(3)
and 176.1(3)°, a larger spread than for the two other
compounds, and one that must be attributed to crystal
packing forces,45 rather than to differences between the
fluorinated and hydrocarbon ligands. Clearly, the
M-benzyne bond is easily deformed by such puckering.
The distances from the metal to the ligated benzyne
carbon atoms C(11) and C(12) are not significantly
different between the tetrafluorobenzyne complex 6 and
its hydrocarbon analogue 15, with averaged values
being identical at 2.062(5) and 2.062(3) Å, respectively.
In the rhodium-tetrafluorobenzyne analogue 11 there
is significant asymmetry between the two Rh-C dis-
tances in each independent molecule, with each struc-
ture having the P-C(17) bond eclipsing the Rh-C(12)
(45) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson,
D. G.; Taylor, R. J . Chem. Soc., Dalton Trans. 1989, S1-S83.

Ir and Rh Complexes with Fluorinated Ph Ligands
Organometallics, Vol. 21, No. 22, 2002 4881
F igu r e 9. Partial ORTEP diagrams showing projections of compounds 2, 12, 17, 3, 9, 13, 18, and 14 as viewed down the
M-C(1) bond. The cyclopentadienyl rings are omitted, and only the centroid of these rings (Ct(01)) is shown, oriented
perpendicular to the M-C(1) bond.
Con clu d in g Rem a r k s
Exp er im en ta l Section
All reactions were performed in oven-dried glassware, using
standard Schlenk techniques under an atmosphere of nitrogen
that had been deoxygenated over BASF catalyst and dried over
Aquasorb, or in a Braun Drybox. Methylene chloride, hexane,
diethyl ether, and toluene were dried over an alumina column
under nitrogen. IR spectra were recorded on a Perkin-Elmer
FTIR 1600 series spectrometer. NMR spectra were recorded
The synthesis of fluorinated and nonfluorinated ben-
zyne ligands from fluoroaryl hydrido complexes has been
extended. The reaction appears to be general, at least
for compounds of Ir and Rh. Detailed interpretations of
structural differences between benzyne and tetrafluo-
robenzyne complexes using crystallographic means are
inappropriate, as crystal-packing forces clearly have a
greater impact on their structures than do chemical
differences between the fluorinated and nonfluorinated
ligands.
1
on a Varian Unity Plus 300 or 500 FT spectrometer. H NMR
spectra were referenced to the protio impurity in the solvent;
C6D6 (δ 7.16 ppm), CDCl3 (δ 7.27 ppm), CD2Cl2 (δ 5.32 ppm).
19F NMR spectra were referenced to CFCl3 (0.00 ppm), and

4882 Organometallics, Vol. 21, No. 22, 2002
Hughes et al.
Ta ble 3. Selected Dista n ces (Å) a n d An gles (d eg)
in Ben zyn e Com p lexes
11b
624
2.0q58(5) 2.062(3)
2.046(5) 2.062(3)
15c
M-C(11)
2.023(3), 2.015(3)
2.067(3), 2.049(3)
M-C(12)
M-P(1)
2.2671(9), 2.2614(9) 2.2573(13) 2.2347(13)
M-Ct(01)a
C(11)-C(12)
C(12)-C(13)
C(13)-C(14
C(14)-C(15)
C(15)-C(16)
C(16)-C(11)
1.860(3), 1.858(3)
1.349(5), 1.343(5)
1.350(5), 1.343(5)
1.409(6), 1.402(6)
1.363(6), 1.382(7)
1.390(6), 1.374(6)
1.353(5), 1.357(5)
1.858(3)
1.374(7)
1.357(7)
1.393(8)
1.355(9)
1.418(9)
1.360(7)
1.877(4)
1.350(7)
1.376(5)
1.415(5)
1.372(8)
1.415(5)
1.376(5)
C(11)-C(12)-C(13) 120.6(3), 122.3(4)
C(12)-C(13)-C(14) 118.1(4), 117.2(4)
C(13)-C(14)-C(15) 120.0(4), 120.3(4)
C(14)-C(15)-C(16) 121.0(4), 120.2(4)
C(15)-C(16)-C(11) 116.8(4), 117.9(4)
C(16)-C(11)-C(12) 123.6(4), 122.1(4)
122.4(5)
117.5(5)
121.2(5)
120.3(5)
117.8(5)
120.6(5)
133.9(4)
123.2(2)
115.2(4)
121.6(2)
121.6(2)
115.2(4)
123.2(2)
132.9(4)
Ct(01)-M-P(1)
133.4(4), 133.3(4)
F igu r e 10. ORTEP diagram of the non-hydrogen atoms
of one of the crystallographically independent molecules
of compound 11, with thermal ellipsoids shown at the 30%
level.
a
b
Ct(01) ) centroid of Cp* [C(1) - C(5)]. Two independent
molecules in asymmetric unit. c For consistency within this table,
atoms in compound 15 that are related by the crystallographic
symmetry plane have been numbered differently, to be consistent
with the numbering scheme in the other two structures: i.e., C(12)
) C(11)′, C(13) ) C(16)′, C(14) ) C(15)′.
21 °C): δ 2.06 (s, 15H, Cp*). 19F NMR (CDCl3, 282.2 MHz, 21
°C): δ -163.0 (br, m-C6F5), -159.8 (dd, 3J FF ) 20.0 Hz, 3J FF
20.0 Hz, p-C6F5), -111.1 (br, o-C6F5), -108.6 (br, o-C6F5).
)
Ir Cp *(C6F 5)(P Me3)I (3). To a solution of IrCp*(C6F5)(CO)I
(2; 137.5 mg, 0.212 mmol) in toluene (15 mL) was added PMe3
(0.030 mL, 0.29 mmol). The resultant solution was refluxed
for 3.5 h, cooled to room temperature, and filtered through
Celite. The solvent was removed in vacuo from the filtrate and
the residual solid recrystallized from CH2Cl2/hexanes. Yield:
127 mg, 86%. Anal. Calcd for C19H24F5IIrP: C, 32.72; H, 3.47.
1
Found: C, 32.52; H, 3.23. H NMR (CDCl3, 300 MHz, 21 °C):
2
6
δ 1.78 (dd, J HP ) 10.2 Hz, J HF ) 1.5 Hz, 9H, PMe3), 1.81 (d,
4J HP ) 2.4 Hz, 15H, Cp*). 19F NMR (CDCl3, 282.2 MHz, 21
3
3
5
°C): δ - 165.7 (dddd, J FF ) 32.0 Hz, J FF ) 20.0 Hz, J FF
)
4
3
8.5 Hz, J FF ) 4.0 Hz, m-C6F5), -163.4 (dddd, J FF ) 29.0 Hz,
3J FF ) 20.0 Hz, J FF ) 7.5 Hz, J FF ) 4.0 Hz, m-C6F5), -162.4
5
4
3
3
3
F igu r e 11. ORTEP diagram of the non-hydrogen atoms
of compound 15, with thermal ellipsoids shown at the 30%
level. Atoms labeled with a prime (′) are crystallographi-
cally related to their unprimed analogues by a plane of
symmetry containing P(1), Ir(1), and C(4).
(dd, J FF ) 20.0 Hz, J FF ) 20.0 Hz, p-C6F5), -113.6 (dd, J FF
4
3
) 32.0 Hz, J FP ) 19.0 Hz, o-C6F5), -102.3 (ddd, J FF ) 29.0
Hz, 5J FF ) 8.5 Hz, 4J FF ) 6.0 Hz, o-C6F5). 31P{1H}NMR (CDCl3,
4
121.4 MHz, 21 °C) δ -43.3 (d, J PF ) 19.0 Hz, PMe3).
[Ir Cp *(C6F 5)(P Me3)(OH2)]O3SCF 3 (4a ) a n d Ir Cp *(C6F 5)-
(P Me3)O3SCF 3 (4b). A solution of IrCp*(C6F5)(PMe3)I (3; 500
mg, 0.717 mmol) in toluene (20 mL) was added slowly dropwise
to rapidly stirred AgO3SCF3 (221 mg, 0.860 mmol), and the
resultant suspension was stirred for 30 min. The mixture was
filtered through Celite and the filtrate reduced in vacuo to a
yellow solid, which was recrystallized from CH2Cl2/hexanes.
Yield: 519 mg, 98%. Anal. Calcd for C20H26F8IrO4PS: C, 33.38;
H, 3.64. Found: C, 33.33; H, 3.16. [IrCp*(C6F5)(PMe3)(OH2)]O3-
SCF3 (4a ): 1H NMR (CD2Cl2, 500 MHz, -40 °C) δ 1.51 (d, 2J HP
31P{1H} NMR spectra were referenced to 85% H3PO4 (0.00
ppm). Coupling constants are reported in hertz. Elemental
analyses were performed by Schwartzkopf (Woodside, NY).
Iodopentafluorobenzene and 2,3,4,5-tetrafluorobenzoyl chloride
(Lancaster) and pentamethylcyclopentadiene and ethyltetra-
methylcyclopentadiene (Aldrich) were used as received. Cp*M-
(CO)2 (M ) Ir, Rh)44 and [Ir(C5Me4Et)Cl2]246 were prepared by
the literature methods.
Ir Cp *(C6F 5)(CO)I (2). To a solution of IrCp*(CO)2 (756 mg,
1.97 mmol) in benzene (40 mL) was added C6F5I (0.30 mL,
2.25 mmol), and the resultant solution was gently refluxed for
40 h to give an orange-purple solution. Removal of solvent,
followed by recrystallization of the solid residue from CH2Cl2/
hexanes, gave a brown crystalline solid (1.090 g), containing
the desired product, contaminated with about 5% of IrCp*-
(CO)I2. Complete purification was achieved by passing through
a Florisil column (CH2Cl2/hexanes, 50:50) to give 2 as a yellow
crystalline solid (80%). Anal. Calcd for C17H15F5IIrO: C, 31.44;
H, 2.33. Found: C, 31.47; H, 2.22. 1H NMR (CDCl3, 300 MHz,
4
) 11.0 Hz, 9H, PMe3), 1.62 (d, J HP ) 1.5 Hz, 15H, Cp*); 19F
NMR (CD2Cl2, 470.3 MHz, -40 °C) δ - 160.9 (ddd, 3J FF ) 20.0
3
5
3
Hz, J FF ) 30.5 Hz, J FF ) 7.0 Hz, m-C6F5), -160.6 (ddd, J FF
3
5
) 20.0 Hz, J FF ) 29.0 Hz, J FF ) 7.5 Hz, m-C6F5), -158.5
(dd, 3J FF ) 20.0 Hz, 3J FF ) 20.0 Hz, p-C6F5), -121.8 (d, 3J FF
)
3
5
29.0 Hz, o-C6F5), -112.8 (ddd, J FF ) 30.5 Hz, J FF ) 7.5 Hz,
4J FP ) 11.0 Hz, o-C6F5), -77.7 (s, O3SCF3); 31P{1H} NMR (CD2-
4
Cl2, 202.3 MHz, -75 °C) δ -22.9 (d, J PF ) 11.1 Hz, PMe3).
IrCp*(C6F5)(PMe3)O3SCF3 (4b): 1H NMR (CD2Cl2, 300 MHz,
21 °C) δ 1.62 (d, 2J HP ) 10.8 Hz, 9H, PMe3), 1.69 (t, 4J HP ) 2.1
Hz, 15H, Cp*); 19F NMR (CD2Cl2, 470.3 MHz, -75 °C) δ -
162.5 (m, m-C6F5), -161.7 (m, m-C6F5), -159.8 (dd, 3J FF ) 20.5
3
3
Hz, J FF ) 20.5 Hz, p-C6F5), -114.7 (d, J FF ) 30 Hz, o-C6F5),
-113.8 (d, J FF ) 27 Hz, o-C6F5), -77.6 (s, O3SCF3); 31P{1H}
3
(46) Dooley, T.; Fairhurst, G.; Chalk, C. D.; Tabatabaian, K.; White,
C. Transition Met. Chem. 1978, 3, 299-302.
NMR (CD2Cl2, 202.3 MHz, -75 °C) δ -18.9 (m).

Ir and Rh Complexes with Fluorinated Ph Ligands
Organometallics, Vol. 21, No. 22, 2002 4883
Ir Cp *(C6F 5)(P Me3)H (5). (a) A solution of [IrCp*(C6F5)-
(PMe3)(OH2)]O3SCF3 (4a ; 280 mg, 0.380 mmol) and 1,8-bis-
(dimethylamino)naphthalene (79 mg, 0.369 mmol) in toluene
(20 mL) was stirred for 3 h. The solvent was removed in vacuo
the residual solid suspended in hexanes (15 mL), and the
suspension stirred vigorously for 5 min. The solvent was
removed in vacuo, the residual solid was extracted into
hexanes (15 mL), and the suspension was filtered. The
colorless filtrate was reduced in vacuo to a white solid. Yield:
190 mg, 88%.
Rh Cp *(C6F 5)(P Me3)I (9). To a solution of IrCp*(C6F5)(CO)I
(8; 284 mg, 0.507 mmol) in toluene (20 mL) was added PMe3
(0.068 mL, 0.66 mmol) and the resultant solution stirred at
room temperature for 2.5 h to give a vibrant orange solution.
The volatiles were removed in vacuo and the residual orange
solid recrystallized from CH2Cl2/hexanes. Yield: 299 mg, 97%.
Anal. Calcd for C19H24F5IPRh: C, 37.52; H, 3.98. Found: C,
1
37.67; H, 3.87. H NMR (CDCl3, 300 MHz, 21 °C): δ 1.68 (d,
4
2J HP ) 10.2 Hz, 9H, PMe3), 1.79 (d, J HP ) 3.3 Hz, 15H, Cp*).
3
19F NMR (CDCl3, 282.2 MHz, 21 °C): δ - 164.7 (ddddd, J FF
3
5
4
4
) 34.2 Hz, J FF ) 21 Hz, J FF ) 8.5 Hz, J FF ) 4.0 Hz, J FRh
)
(b) A less pure sample was obtained by reaction of IrCp*-
3
3
3.7 Hz, m-C6F5), -162.5 (ddm, J FF ) 31.3 Hz, J FF ) 21 Hz,
(C6F5)(PMe3)I (3) and NaBH4 in refluxing 2-propanol:
a
3
3
m-C6F5), -161.3 (dd, J FF ) 21 Hz, J FF ) 21 Hz, p-C6F5),
mixture of IrCp*(C6F5)(PMe3)I (70 mg, 0.100 mmol) and
NaBH4 (50 mg, 1.32 mmol) in 2-propanol (15 mL) was heated
under reflux for 4 h. The solvent was removed, the solid
residue extracted into hexanes, and the mixture filtered. The
colorless filtrate was reduced in vacuo to a yellow oil, which
solidified on standing to a tan solid. The product was contami-
nated with entrained 2-propanol. 1H NMR (C6D6, 300 MHz,
3
4
5
-112.5 (ddddd, J FF ) 34.2 Hz, J FP ) 25.3 Hz, J FF ) 7 Hz,
4J FF ) 8 Hz, J FRh ) 7 Hz, o-C6F5), -98.0 (dddd, J FF ) 31.3
3
3
Hz, J FF ) 8.5 Hz, J FF ) 8 Hz, J FRh ) 2.5 Hz, o-C6F5). 31P-
5
4
3
{1H} NMR (CDCl3, 121.4 MHz, 21 °C): δ 0.6 (dd, 1J PRh ) 144.3
4
Hz, J PF ) 25.3 Hz, PMe3).
Rh Cp *(C6F 5)(P Me3)H (10). A mixture of RhCp*(C6F5)-
(PMe3)I (9; 10 mg, 0.016 mmol) and NaBH4 (10 mg, 0.26 mmol)
in d8-THF (0.7 mL) was heated in an evacuated J . Young NMR
tube in an oil bath at 50 °C for 16 h. The solution slowly
changed from orange to colorless. NMR showed complete
conversion to the desired product. Yield: quantitative. 1H NMR
2
4
21 °C): δ -16.48 (dd, J HP ) 37.8 Hz, J HF ) 10.8 Hz, 1H,
2
4
Ir-H), 0.97 (d, J HP ) 9.9 Hz, 9H, PMe3), 1.70 (dd, J HP ) 1.8
Hz, J HH ) 0.8 Hz, 15H, Cp*). 19F NMR (C6D6, 282.2 MHz, 21
4
3
3
5
°C): δ - 165.7 (dddd, J FF ) 35.0 Hz, J FF ) 20.5 Hz, J FF
)
4
3
9.5 Hz, J FF ) 4.0 Hz, m-C6F5), -164.6 (dddd, J FF ) 31.5 Hz,
2
3J FF ) 20.5 Hz, J FF ) 9.0 Hz, J FF ) 4.0 Hz, m-C6F5), -164.2
5
4
(d8-THF, 500 MHz, 21 °C): δ -12.80 (ddd, J HP ) 48.5 Hz,
4
2
1J HRh ) 25.5 Hz, J HF ) 10.5 Hz, 1H, Rh-H), 1.23 (d, J HP
)
3
3
3
(dd, J FF ) 20.5 Hz, J FF ) 20.5 Hz, p-C6F5), -111.8 (dm, J FF
) 35.0 Hz, o-C6F5), -107.6 (dd., 3J FF ) 31.5 Hz, 5J FF ) 9.5 Hz,
4J FH ) 11.0 Hz, o-C6F5). 31P{1H} NMR (C6D6, 121.4 MHz, 21
10.5 Hz, 9H, PMe3), 1.85 (d, 4J HP ) 2.5 Hz, 15H, Cp*). 19F NMR
(d8-THF, 470.4 MHz, 21 °C): δ -163.0 (m, m-C6F5), -162.4
3
3
4
4
(m, m-C6F5), -162.0 (dd, J FF ) 20 Hz, J FF ) 20 Hz, p-C6F5),
°C): δ -44.5 (dd, J PF ) 6.8 Hz, J PF ) 2.9 Hz, PMe3).
-107.4 (dm, J FF ) 37 Hz, o-C6F5), -102.4 (m, o-C6F5). 31P-
3
Ir Cp *(η2-C6F 4)(P Me3) (6). To a solution of IrCp*(C6F5)-
(PMe3)H (190 mg, 0.332 mmol) in hexanes (20 mL) at -78 °C
was added a solution of n-BuLi in hexanes (1.0 mL, 3.8 M, 3.8
mmol). The resultant yellow solution was warmed to room
temperature and was stirred for 20 h. The resultant murky
yellow solution was cooled in an ice bath, and ca. 2 mL of
MeOH was added to the stirred solution. Removal of volatiles
in vacuo gave a yellow solid, which was extracted into hexanes
and the mixture filtered. Removal of solvent in vacuo gave an
off-white solid. Yield: 181 mg, 99%. X-ray-quality crystals were
grown by slow evaporation of a hexane solution; details of the
{1H} NMR (C6D6, 121.4 MHz, 21 °C): δ 9.3 (ddd, 1J PRh ) 142.2
4
4
Hz, J PF ) 9.3 Hz, J PF ) 9.3 Hz, PMe3).
Rh Cp *(η2-C6F 4)(P Me3) (11). To a solution of RhCp*(C6F5)-
(PMe3)H (10; freshly prepared from RhCp*(C6F5)(PMe3)I (76
mg, 0.0125 mmol) and NaBH4) in hexanes (15 mL) at -78 °C
was added a solution of n-BuLi in hexanes (0.06 mL, 2.8 M,
0.017 mmol). The resultant yellow solution was warmed to
room temperature and was stirred for 1 h. An orange-yellow
cloudy solution was produced. Cooling to 0 °C and addition of
1 mL of MeOH to the stirred solution, followed by removal of
volatiles in vacuo, extraction into hexanes, and filtration, gave
a pale yellow filtrate which was reduced in vacuo to a pale
yellow solid. Yield: 48 mg, 84%. X-ray-quality crystals were
grown by slow evaporation of a hexane solution and subse-
quent washing with hexanes. Anal. Calcd for C19H24F4PRh:
C, 49.37; H, 5.23. Found: C, 48.74; H, 5.34. 1H NMR (C6D6,
structural determination appear elsewhere.24 Anal. Calcd for
1
C
19H24F4IrP: C, 41.37; H, 4.39. Found: C, 41.48; H, 4.31. H
2
NMR (C6D6, 300 MHz, 21 °C): δ 0.67 (d, J HP ) 9.9 Hz, 9H,
PMe3), 1.65 (d, 4J HP ) 1.5 Hz, 15H, Cp*). 13C{1H} NMR (C6D6,
3
125.7 MHz, 21 °C): δ 10.15 (d, J CP ) 0.75 Hz, C5Me5), 17.90
1
2
(d, J CP ) 38.2 Hz, PMe3), 84.2 (m, i-C6F4), 92.46 (d, J CP
)
2
3
3.5 Hz, C5Me5), 135.28 (dm, 1J CF ) 252 Hz, o- or m-C6F4), 142.8
(dm, 1J CF ) 253 Hz, o- or m-C6F4). 19F NMR (C6D6, 282.2 MHz,
300 MHz, 21 °C): δ 0.49 (dd, J HP ) 9.9 Hz, J HRh) 1.2 Hz,
9H, PMe3), 1.59 (dd, 4J HP ) 2.7 Hz, 3J HRh ) 0.6 Hz, 15H, Cp*).
19F NMR (C6D6, 282.2 MHz, 21 °C): δ -149.4 (m (FAFA′FXFX′),
3
3
21 °C): δ -151.5 (m (FAFA′FXFX′), J F(XX′) ) 40.8 Hz, J F(AX)
)
3J F(XX′) ) 41.3 Hz, 3J F(AX) ) 30.0 Hz, 5J F(AA′) ) 11.8 Hz, J F(AX′)
)
5
29.3 Hz, J F(AA′) ) 11.5 Hz, J F(AX′) ) 1.2 Hz, m-C6F4), -143.5
4
4
3
3
1.4 Hz, m-C6F4), -141.6 (dm (FAFA′FXFX′), J FRh ) 4.5 Hz,
(dm (FAFA′FXFX′), J FP ) 1.4 Hz, J F(XX′) ) 40.8 Hz, J F(AX)
)
3J F(XX′) ) 41.3 Hz, 3J F(AX) ) 30.0 Hz, 5J F(AA′) ) 11.8 Hz, J F(AX′)
)
29.3 Hz, J F(AA′) ) 11.5 Hz, J F(AX′) ) 1.2 Hz, o-C6F4). 31P{1H}
5
1.4 Hz, o-C6F4). 31P{1H} NMR (C6D6, 121.4 MHz, 21 °C): δ
NMR (C6D6, 121.4 MHz, 21 °C): δ -37.2 (PMe3). 13C{1H} NMR
1
3
-1.46 (d, J PRh ) 167 Hz, PMe3).
(C6D6, 125.7 MHz, 21 °C): δ 10.15 (d, J CP ) 0.75 Hz, C5Me5),
17.90 (d, 1J CP ) 38.2 Hz, PMe3), 84.2 (m, i-C6F4), 92.46 (d, 2J CP
Ir Cp *(2-C6F H4)(CO)I (12). To a solution of IrCp*(CO)2 (545
mg, 1.42 mmol) in toluene (50 mL) was added 2-fluoro-1-
iodobenzene (0.35 mL, 0.665 g, 3.0 mmol). The mixture was
heated in an oil bath at 140 °C for 48 h. A reddish brown
solution was produced, and this was cooled to room temper-
ature. The solvent was removed in vacuo to produce a brown
solid, which was purified by column chromatography (silica;
toluene). The resultant yellow solution was reduced in vacuo
to a yellow solid, which was recrystallized from CH2Cl2/
hexanes to give X-ray-quality crystals. Yield: 535 mg, 65%.
Anal. Calcd for C17H19FIIrO: C, 35.36; H, 3.32. Found: C,
1
) 3.5 Hz, C5Me5), 135.28 (dm, J CF ) 252 Hz, o- or m-C6F4),
1
142.8 (dm, J CF ) 253 Hz, o- or m-C6F4).
Rh Cp *(C6F 5)(CO)I (8). To a sample of RhCp*(CO)2 (238
mg, 0.809 mmol) in toluene (20 mL) was added C6F5I (0.14
mL, 1.05 mmol) and the solution stirred in an oil bath at 80
°C for 48 h. The volume of the resultant red solution was
reduced in vacuo and the mixture passed through a column
(silica, toluene). The first, orange band was discarded, and the
second, red band was collected. The solvent was removed to
give a brown-orange solid, which was recrystallized from CH2-
Cl2/hexanes. Yield: 345 mg, 76%. Anal. Calcd for C17H15F5-
1
35.48; H, 3.17. H NMR (CDCl3, 300 MHz, 22 °C): δ 1.95 (s,
1
15H, Cp*), 6.85 (m, 2H, C6H4F), 6.94 (m, 1H, C6H4F), 7.67 (m,
1H, C6H4F). 19F NMR (CDCl3, 300 MHz, 22 °C): δ 87.79 (m,
C6H4F).
Ir Cp *(2-C6F H4)(P Me3)I (13). A solution of IrCp*(CO)-
(C6H4F)I (12; 215 mg, 0.37 mmol) in dry toluene (50 mL) was
IORh: C, 36.45; H, 2.70. Found: C, 36.20; H, 2.79. H NMR
(CDCl3, 300 MHz, 21 °C): δ 2.01 (s, 15H, Cp*). 19F NMR
(CDCl3, 282.2 MHz, 21 °C): δ -162.2 (br, m-C6F5), -159.1 (dd,
3J FF ) 19.5 Hz, 3J FF ) 19.5 Hz, p-C6F5), -110 (br, o-C6F5), -105
(br, o-C6F5).

4884 Organometallics, Vol. 21, No. 22, 2002
Hughes et al.
degassed, and PMe3 (0.06 mL, 0.042 g, 0.56 mmol) was added
by syringe. The reaction mixture was heated under reflux for
3 h and cooled to room temperature. All volatiles were removed
under vacuum, and the residue was crystallized from CH2Cl2/
hexanes to give crystals of X-ray quality. Yield: 217 mg, 92%.
Anal. Calcd for C19H28FIIrP: C, 36.48; H, 4.51. Found: C,
Hz, 2H, o-C6H5). 13C{1H} NMR (CDCl3, 125.7 MHz, 22 °C) δ
1.36 (d, 2J CP ) 9.3 Hz, R-CH2), 9.09 (d, 3J CP ) 0.75 Hz, C5Me5),
1
14.07 (s, δ-CH2), 15.53 (d, J CP ) 35.8 Hz, PMe3), 29.2 (s, 1C,
3
2
γ-CH2), 39.06 (d, J CP ) 4.9 Hz, â-CH2), 93.00 (d, J CP ) 3.6
Hz, C5Me5), 120.21 (s, p-C6H5), 126.34 (s, m-C6H5), 137.79 (d,
2J CP ) 12.6 Hz, i-C6H5), 139.63 (d, 3J CP ) 3.3 Hz, o-C6H5). 31P-
{1H} NMR (C6D6, 121.4 MHz, 22 °C): δ -39.8 (s, PMe3).
Ir (C5Me4Et)(CO)2. A solution of [Ir(C5Me4Et)Cl2]2 (301 mg,
0.730 mmol) and Fe3(CO)12 (methanol stabilized, 300 mg, 0.59
mmol) in benzene (50 mL) was heated under reflux in air for
16 h to give a brown murky solution. The mixture was cooled
to room temperature and then filtered through Celite. If any
green color remained in the solution, it was allowed to stand
in air for 24 h. The solvent was then removed in vacuo and
the solid residue extracted into hexanes and then filtered
through Celite. The solvent was removed to give a brown oil,
which became a waxy dark yellow solid on standing. Yield:
243 mg, 84%. 1H NMR (CDCl3, 500 MHz, 21 °C): δ 1.09 (t,
3J HH ) 7.5 Hz, 3H, CH2CH3), 2.17 (s, 6H, C5Me4Et), 2.18 (s,
1
36.58; H, 4.38. H NMR (CDCl3, 300 MHz, 22 °C): δ 1.67 (d,
4
2J HP ) 10.5 Hz, 9H, PMe3), 1.74 (d, J HP ) 1.8 Hz, 15H, Cp*),
6.72 (m, 2H, C6H4F), 6.83 (m, 1H, C6H4F), 8.08 (m, 1H, C6H4F).
4
19F NMR (CDCl3, 282.2 MHz, 22 °C): δ 88.27 (m, J FP ) 10.5
Hz, 1F, C6H4F). 31P{1H} NMR (CDCl3, 121.4 MHz, 22 °C): δ
4
43.66 (d, J FP ) 10.5 Hz, PMe3)
Ir Cp *(P Me3)(2-C6F H4)H (14). IrCp*(PMe3)(C6H4F)I (13;
215 mg, 0.37 mmol) was placed in a Schlenk flask, and ethanol
(50 mL of 95%) and NaBH4 (130 mg, 3.4 mmol) were added.
The reaction mixture was heated to 60-70 °C, and the
resultant yellow solution was stirred for 30 min until it became
colorless. All volatiles were removed under vacuum. The
residue was extracted with dry hexane, the resultant solution
was filtered, and almost all the hexane was removed under
vacuum. The solution was cooled, and crystals of X-ray quality
3
6H, C5Me4Et), 2.46 (q, J HH ) 7.5 Hz, 2H, CH2CH3).
Ir (C5Me4Et)(2,3,4,5-C6F 4H)(CO)Cl (17). A solution of Ir-
(C5Me4Et)(CO)2 (16; 243 mg, 0.611 mmol) and 2,3,4,5-tet-
rafluorobenzoyl chloride (0.16 mL, 1.2 mmol) in toluene (15
mL) was heated in an oil bath at 110 °C for 48 h to give a
yellow solution. The solvent was removed in vacuo and the
solid residue purified by column chromatography (silica, 1:1
toluene/CH2Cl2). The yellow band was collected and the solvent
removed in vacuo to give a yellow solid, which was recrystal-
lized from CH2Cl2/hexanes. Yield: 252 mg, 74%. Anal. Calcd
for C18H18ClF4IrO: C, 39.02; H, 3.28. Found: C, 38.92; H, 3.32.
were obtained. Yield: 148 mg, 87%. Anal. Calcd for C19H29
-
FIrP: C, 45.68; H, 5.85. Found: C, 45.96; H, 5.75. Major
rotamer: 1H NMR (CD2Cl2, 500 MHz, -60 °C) δ -17.44 (d,
2J HP ) 35.5 Hz, 1H, Ir-H), 1.28 (d, 2J HP ) 10.0 Hz, 9H, PMe3),
1.81 (m, 15H, Cp*), 6.50 (m, 1H, C6H4F), 6.58 (m, 1H, C6H4F),
6.75 (m, 1H, C6H4F), 7.49 (m, 1H, C6H4F); 19F NMR (CD2Cl2,
470.3 MHz, -60 °C) δ 87.79 (br, 1F, C6H4F); 31P{1H} NMR
4
(CD2Cl2, 202.35 MHz, -60 °C) δ -41.33 (d, J FP ) 4.4 Hz, 1P,
PMe3). Minor rotamer: 1H NMR (CD2Cl2, 500 MHz, -60 °C)
δ -16.73 (dd, 2J HP ) 37.3 Hz, 4J HF ) 10.3 Hz, 1H, Ir-H), 1.25
3
1H NMR (C6D6, 500 MHz, 21 °C): δ 0.87 (t, J HH ) 8.0 Hz,
2
(d, J HP ) 10.0 Hz, 9H, PMe3), 1.81 (m, 15H, Cp*), 6.58 (m,
3H, CH2CH3), 1.76 (s, 3H, C5Me4Et), 1.78 (s, 3H, C5Me4Et),
3
1H, C6H4F), 6.63 (m, 1H, C6H4F), 6.75 (m, 1H, C6H4F), 7.29
(m, 1H, C6H4F); 19F NMR (CD2Cl2, 470.3 MHz, -60 °C) δ 84.82
(s, 1F, C6H4F); 31P{1H} NMR (CD2Cl2, 202.35 MHz, -60 °C) δ
-38.57 (s, 1P, PMe3).
1.86 (s, 3H, C5Me4Et), 1.90 (s, 3H, C5Me4Et), 2.17 (q, J HH
)
3
4
8.0 Hz, 2H, CH2CH3), 6.57 (dddd, J HF ) 10.8 Hz, J HF ) 8.9
Hz, 5J HF ) 2.8 Hz, 4J HF ) 1.9 Hz, 1H, C6F4H). 19F NMR (CDCl3,
470.3 MHz, 21 °C): δ -162.6 (ddd, 3J FF ) 21.2 Hz, 3J FF ) 18.8
Hz, 4J FH ) 8.9 Hz, p-C6F4H), -158.4 (ddd, 3J FF ) 26.8 Hz, 3J FF
) 18.8 Hz, J FH ) 2.8 Hz, m-C6F4H), -141.9 (ddd, J FF ) 21.2
Hz, J FF ) 12.7 Hz, J FH ) 10.8 Hz, m-C6F4H), -115.9 (ddd,
Ir Cp *(η2-C6H4)(P Me3) (15). To a solution of IrCp*(PMe3)(2-
C6FH4)H (14; 110 mg, 0.220 mmol) in hexanes (25 mL) was
added a solution of n-BuLi in hexane (1.0 mL, 2.8 M, 2.2
mmol). The resultant yellow solution was stirred for 4 h at
room temperature. Cooling to 0 °C and addition of ∼0.3 mL of
MeOH to the stirred solution, followed by removal of volatiles
in vacuo, gave an off-white solid which was extracted into
hexanes and filtered. Pale yellow crystals were grown by slow
evaporation of a hexane solution. Yield: 65 mg, 62%. Anal.
Calcd for C19H28IrP: C, 47.58; H, 5.88. Found: C, 47.29; H,
5
3
5
3
3J FF ) 26.8 Hz, J FF ) 12.7 Hz, J FH ) 1.9 Hz, o-C6F4H).
Ir (C5Me4Et)(2,3,4,5-C6F 4H)(P Me3)Cl (18). A solution of Ir-
(C5Me4Et)(2,3,4,5-C6F4H)(CO)Cl (17; 241 mg, 0.435 mmol) and
PMe3 (0.06 mL, 0.58 mmol) in toluene (15 mL) was heated in
an oil bath at 95 °C for 16 h. The resultant yellow solution
was reduced in vacuo to a yellow solid, which was recrystal-
lized from CH2Cl2/hexanes. Yield: 244 mg, 93%. Anal. Calcd
for C20H27ClF4IrP: C, 39.90; H, 4.52. Found: C, 40.02; H, 4.54.
5
4
1
2
5.79. H NMR (C6D6, 300 MHz, 22 °C): δ 0.85 (d, J HP ) 9.9
4
1H NMR (CDCl3, 300 MHz, 21 °C): δ 1.04 (t, J HH ) 7.5 Hz,
3
Hz, 9H, PMe3), 1.85 (d, J HP ) 1.8 Hz, 15H, Cp*), 7.08 (m
3
3
5
3H, CH2CH3), 1.46 (d, 2J HP ) 10.8 Hz, 9H, PMe3), 1.61 (d, 4J HP
(HAHA′HXHX′), J H(XX) ) 7.0 Hz, J H(AX) ) 6.1 Hz, J H(AA′) ) 1.7
4
3
) 2.4 Hz, 6H, C5Me4Et), 1.67 (d, 4J HP ) 2.4 Hz, 3H, C5Me4Et),
Hz, J H(AX′) ) 0.5 Hz), 7.40 (m (HAHA′HXHX′), J H(XX) ) 7.0 Hz,
3J H(AX) ) 6.1 Hz, J H(AA′) ) 1.7 Hz, J H(AX′) ) 0.5 Hz). 13C{1H}
5
4
4
3
1.68 (d, J HP ) 1.8 Hz, 3H, C5Me4Et), 2.01 (q, J HH ) 7.5 Hz,
2H, CH2CH3), 6.62 (ddddd, 3J HF ) 12.0 Hz, 4J HF ) 9.6 Hz, 4J HF
3
NMR (C6D6, 125.7 MHz, 22 °C): δ 10.84 (d, J CP ) 1.15 Hz,
1
2
) 3 Hz, J HF ) 3 Hz, J HP ) 1.2 Hz, 1H, C6F4H). 19F NMR
5
4
C5Me5), 18.70 (d, J CP ) 37.6 Hz, PMe3), 92.38 (d, J CP ) 3.8
2
3
Hz, C5Me5), 107.88 (d, J CP ) 9.2 Hz, i-C6H4), 116.27 (s, o- or
(CDCl3, 470.3 MHz, 21 °C): δ -165.7 (ddd, J FF ) 21.2 Hz,
m-C6H4), 126.85 (s, o- or m-C6H4). 31P{1H} NMR (C6D6, 121.4
MHz, 22 °C): δ -37.52 (s, PMe3).
3
3
3J FF ) 18.9 Hz, J FH ) 9.6 Hz, p-C6F4H), -160.6 (ddd, J FF
)
3
5
30.5 Hz, J FF ) 18.9 Hz, J FH ) 3 Hz, m-C6F4H), -143.7 (ddd,
3J FF ) 21.2 Hz, J FF ) 13.5 Hz, J FH ) 12.0 Hz, o-C6F4H),
5
3
Ir Cp *(C6H5)(P Me3)(n -Bu ) (16). To a solution of IrCp*-
(PMe3)(2-C6FH4)H (14; 40 mg, 0.08 mmol) in hexanes (20 mL)
was added a solution of n-BuLi in hexane (0.3 mL, 2.8 M, 0.8
mmol). The resultant yellow solution was stirred for 2 h at 60
°C. Cooling to 0 °C and addition of ∼0.3 mL of MeOH to the
stirred solution, followed by removal of volatiles in vacuo, gave
an off-white solid which was extracted with hexanes and
filtered. Removal of solvent in vacuo gave a colorless oil, which
was purified by column chromatography (silica, hexanes).
Yield: 20 mg, 48%. Adequate microanalysis results could not
be obtained, and the complex was characterized only spectro-
3
5
4
-117.2 (dddd, J FF ) 30.5 Hz, J FF ) 13.5 Hz, J FH ) 3 Hz,
4J FP ) 6.1 Hz, o-C6F4H). 31P{1H} NMR (CDCl3, 202.3 MHz, 21
4
°C): δ - 35.0 (d, J PF ) 6.1 Hz).
[Ir (C5Me4Et)(2,3,4,5-C6F 4H)(P Me3)(OH2)]O3SCF 3 (19). A
solution of Ir(C5Me4Et)(2,3,4,5-C6F4H)(PMe3)Cl (18; 244 mg,
0.333 mmol) in toluene (20 mL) was added dropwise to rapidly
stirred AgO3SCF3 (114 mg, 0.444 mmol) to form a yellow
solution with a white precipitate. The mixture was stirred for
1.5 h and then filtered through Celite to give a yellow filtrate.
The solvent was removed in vacuo from the filtrate, the
residual solid dissolved in CH2Cl2, and this solution filtered
again through Celite. Addition of hexanes to the filtrate and
removal of the CH2Cl2 in vacuo gave an orange precipitate.
Yield: 281 mg, 95%. Anal. Calcd for C21H29F7IrO4PS: C, 34.38;
1
3
scopically. H NMR (CD2Cl2, 500 MHz, 22 °C): δ 0.91 (t, J HH
) 7.2 Hz, 3H, CH3), 1.35 (d, 2J HP ) 9.6 Hz, 9H, PMe3), 1.59 (d,
4J HP ) 2.1 Hz, 15H, Cp*), 6.75 (tm, 3J HH ) 7.0 Hz, 1H, p-C6H5),
3
3
6.80 (tm, J HH ) 7.0 Hz, 2H, m-C6H5), 7.16 (dm, J HH ) 8.0

Ir and Rh Complexes with Fluorinated Ph Ligands
Organometallics, Vol. 21, No. 22, 2002 4885
2
3
H, 3.98. Found: C, 34.46; H, 3.91. 1H NMR (CD2Cl2, 300 MHz,
0.72 (d, J HP ) 9.9 Hz, 9H, PMe3), 0.93 (t, J HH ) 7.5 Hz, 3H,
3
2
4
4
21 °C): δ 1.05 (t, J HH ) 7.5 Hz, 3H, CH2CH3), 1.53 (d, J HP
)
CH2CH3), 1.67 (d, J HP ) 1.8 Hz, 3H, C5Me4Et), 1.68 (d, J HP
) 1.8 Hz, 3H, C5Me4Et), 1.71 (d, 4J HP ) 1.8 Hz, 6H, C5Me4Et),
2.06 (q, 3J HH ) 7.5 Hz, 2H, CH2CH3), 7.43 (dddd, 3J HF ) 3 Hz,
4J HF ) 3 Hz, 5J HF ) 3 Hz, 4J HP ) 0.9 Hz, 1H, C6F3H). 19F NMR
(C6D6, 282.2 MHz, 21 °C): δ -161.2 (ddd, 3J FF ) 29.1 Hz, 3J FF
10.8 Hz, 9H, PMe3), 1.63 (br, 3H, C5Me4Et), 1.67 (br, 3H, C5Me4-
3
Et), 1.70 (br, 6H, C5Me4Et), 2.08 (q, J HH ) 7.5 Hz, 2H, CH2-
3
4
4
CH3), 7.11 (ddddd, J HF ) 11.4 Hz, J HF ) 9.3 Hz, J HF ) 3.3
Hz, 5J HF ) 3.3 Hz, 4J HP ) 1 Hz, 1H, C6F4H). 19F NMR (CDCl3,
470.4 MHz, 21 °C): δ -163.8 (br, p-C6F4H), -158.3 (br,
m-C6F4H), -141.8 (br, m-C6F4H), -116.7 (br, o-C6F4H), -79.2
(s, O3SCF3). 31P{1H} NMR (CDCl3, 121.4 MHz, 21 °C): δ -22.0
(br).
4
3
) 10.7 Hz, J FH ) 3.1 Hz, m-C6F3H), -141.2 (d, J FF ) 29.1
3
3
Hz, o-C6F3H), -136.8 (dd, J FF ) 10.7 Hz, J FH ) 3 Hz,
m-C6F3H). 31P{1H} NMR (C6D6, 121.4 MHz, 21 °C): δ - 35.8
4
(d, J PF ) 1.6 Hz).
Ir (C5Me4Et)(2,3,4,5-C6F 4H)(P Me3)H (20). A solution of [Ir-
(C5Me4Et)(2,3,4,5-C6F4H)(PMe3)(OH2)]O3SCF3 (19; 263 mg,
0.358 mmol) and Proton Sponge (74 mg, 0.35 mmol) in toluene
(15 mL) was stirred for 2.5 h. The solvent was removed in
vacuo, the residue extracted into hexanes, and the extract
filtered. The solvent was removed from the filtrate to give an
off-white solid. The solid was dissolved in hexanes (15 mL)
and left to stand at -30 °C for 3 h. A yellow precipitate
developed, which was removed by filtration. Removal of solvent
from the filtrate gave a pale yellow oil, which solidified on
standing. Yield: 198 mg, 97%. Crystals were grown by
standing a concentrated hexane solution at -30 °C for 16 h.
Anal. Calcd for C20H28F4IrP: C, 42.32; H, 4.97. Found: C,
42.33; H, 4.88. 1H NMR (C6D6, 300 MHz, 21 °C): δ -17.17
Cr ysta llogr a p h ic Str u ctu r a l Deter m in a tion s. Crystal
data and data collection and refinement parameters are
collected in Table 1. Systematic absences in the diffraction data
for 2 and 11-13 and statistics of intensity for 3, 9, 14, 15, 18,
and 19 are uniquely consistent for the reported space groups
and yielded chemically reasonable and computationally stable
results on refinement. The structures were solved using direct
methods, completed by subsequent difference Fourier synthe-
ses, and refined by full-matrix least-squares procedures.
SADABS absorption corrections47 were applied to all struc-
tures. All non-hydrogen atoms were refined with anisotropic
displacement coefficients, and hydrogen atoms were treated
as idealized contributions.
Compounds 11 and 14 crystallized with two independent
molecules in the asymmetric unit. In compound 14 the single
ortho fluorine is disordered in each molecule between locations
F(21) and F(61). The disorder was successfully modeled with
an F(21)/F(61) occupancy ratio of 0.70/0.30 in molecule 1 and
0.59/0.41 in molecule 2.
2
3
(br, d, J HP ) 35 Hz, 1H, Ir-H), 0.88 (t, J HH ) 7.5 Hz, 3H,
2
CH2CH3), 0.98 (d, br, J HP ) 9.9 Hz, 9H, PMe3), 1.66 (br, 3H,
C5Me4Et), 1.67 (br, 3H, C5Me4Et), 1.70 (br, 3H, C5Me4Et), 1.71
3
(br, 3H, C5Me4Et), 2.08 (q, J HH ) 7.5 Hz, 2H, CH2CH3), 7.43
(br, 1H, C6F4H); a minor isomer was distinguishable only as a
broad hump at -16.2 ppm. 19F NMR (C6D6, 282.2 MHz, 21
°C): δ -167.1 (br, p-C6F4H), -160.6 (br, m-C6F4H), -145.2 (br,
m-C6F4H), -113.9 (br, o-C6F4H); a minor isomer was distin-
guishable as small broad peaks at -159.4, -146.0, and -109.0
ppm. 31P{1H} NMR (C6D6, 121.4 MHz, 21 °C): δ -44.2 (br); a
minor isomer was distinguishable as a broad hump at -42.5
ppm.
All software and sources of scattering factors are contained
in the SHELXTL program libraries (various versions, G.
Sheldrick, Bruker AXS, Madison, WI).
Ack n ow led gm en t. R.P.H. is grateful to the Na-
tional Science Foundation and to the donors of the
Petroleum Research Fund, administered by the Ameri-
can Chemical Society, for generous financial support.
Ir (C5Me4Et)(η2-3,4,5-C6F 3H)(P Me3) (21). To a solution of
Ir(C5Me4Et)(2,3,4,5-C6F4H)(PMe3)H (20; 126 mg, 0.222 mmol)
in hexanes (15 mL) was added a solution of n-BuLi in hexanes
(0.8 mL, 2.8 M, 2.2 mmol). The mixture was stirred for 22 h
to give a yellow cloudy solution. The mixture was cooled in an
ice bath, MeOH (2 mL) was added, and then the volatiles were
removed in vacuo. The solid residue was extracted into
hexanes and filtered. The filtrate was reduced in vacuo to a
pale brown oil. Yield: 120 mg, 99%. Crystals were obtained
by allowing a concentrated hexanes solution to stand at -30
°C for 24 h. Anal. Calcd for C20H27F3IrP: C, 43.87; H, 4.97.
Found: C, 43.96; H, 5.09. 1H NMR (C6D6, 300 MHz, 21 °C): δ
Su ppor tin g In for m ation Available: Tables giving atomic
fractional coordinates, bond distances and angles, and aniso-
tropic thermal parameters for complexes 2, 3, 9, 11-15, 17,
and 18. This material is available free of charge via the
Internet at http://pubs.acs.org.
OM0204787
(47) Sheldrick, G. M. SADABS v2.01: Bruker/Siemens Area Detec-
tor Absorption Correction Program; Bruker AXS, Madison, WI, 1998.