Reactions of iridium and rhodium complexes containing η2-benzyne, η2-tetrafluorobenzyne, and η2-trifluorobenzyne ligands. Differential rates of arene elimination by protonation of isomeric fluoroaryl complexes and restricted rotation of PMe3 ligands in ortho-iodo and ortho-bromoaryl complexes

Article abstract of DOI:10.1021/om030048w

Treatment of the tetrafluorobenzyne complex Cp*Ir(η²-C₆F₄)(PMe₃) (1) with MeCO₂H affords the tetrafluorophenyl complex Cp*Ir(2,3,4, 5,-C₆F₄H)(PMe₃)(O₂CMe) (2), which, on treatment with NaBH₄, affords the hydride complex Cp*Ir(2,3,4,5,-C₆F₄H)(PMe₃)H (3). Treatment of 3 with n-BuLi affords the trifluorobenzyne complex Cp*Ir(3,4,5-C₆F₃H)(PMe₃) (4). Treatment of 4 with MeCO₂H gives a mixture of two protonation products, Cp*Ir(2,3,4-C₆F₃H₂)(PMe₃) (O₂CMe) (5) and Cp*Ir(3,4,5-C₆F₃ H₂)(PMe₃)(O₂CMe) (6) in an 8:1 ratio. Treatment of the 5/6 mixture with CF₃CO₂H affords 1,2,3-C₆F₃H₃ and Cp*Ir (O₂CCF₃)₂(PMe₃) but at dramatically different rates, with 5 reacting significantly faster than 6. Treatment of 1a with Br₂, I₂, or MeI gives the oxidative addition products Cp*Ir(2-C₆BrF₄)Br(PMe₃) (7), Cp*Ir(2-C₆IF₄)I(PMe₃) (8), or Cp*Ir(2-C₆MeF₄)I(PMe₃) (9), respectively. The variable-temperature proton NMR spectra of complexes 7 and 8 reveal an unusual restricted rotation about the Ir-PMe₃ bonds on the NMR time scale (7, ΔG^? = 39 ± 2 kJ mol^-1; 8, ΔG^? = 38 ± 2 kJ mol^-1). Similarly, treatment of Cp*Rh(η²-C₆F₄) (PMe₃) (1b) with I₂ leads to formation of Cp*Rh(2-C₆IF₄)I(PMe₃) (10), which also exhibits restricted rotation about the metal-phosphorus bond (ΔG^? = 44 ± 2 kJ mol^-1). While the tetrafluorobenzyne complex (1a) is unreactive toward CO, the hydrocarbon analogue Cp*Ir(η²-C₆H₄) (PMe₃) (1c) does react to give the CO monoinsertion product (11). Compound 1c also reacts with I₂ to afford Cp*Ir(2-C₆IH₄)I(PMe₃) (12), which also shows restricted rotation about the Ir-PMe₃ bond (ΔG^? = 43 ± 2 kJ mol^-1). X-ray crystal structures of complexes 3, 4, 5, 7, 8, 10, and 11 are reported.

Full text of DOI:10.1021/om030048w

2134
Organometallics 2003, 22, 2134-2141
Rea ction s of Ir id iu m a n d Rh od iu m Com p lexes
Con ta in in g η2-Ben zyn e, η2-Tetr a flu or oben zyn e, a n d
η2-Tr iflu or oben zyn e Liga n d s. Differ en tia l Ra tes of Ar en e
Elim in a tion by P r oton a tion of Isom er ic F lu or oa r yl
Com p lexes a n d Restr icted Rota tion of P Me3 Liga n d s in
or th o-Iod o a n d or th o-Br om oa r yl Com p lexes
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 anuary 22, 2003
Treatment of the tetrafluorobenzyne complex Cp*Ir(η2-C6F4)(PMe3) (1) with MeCO2H
affords the tetrafluorophenyl complex Cp*Ir(2,3,4,5,-C6F4H)(PMe3)(O2CMe) (2), which, on
treatment with NaBH4, affords the hydride complex Cp*Ir(2,3,4,5,-C6F4H)(PMe3)H (3).
Treatment of 3 with n-BuLi affords the trifluorobenzyne complex Cp*Ir(3,4,5-C6F3H)(PMe3)
(4). Treatment of 4 with MeCO2H gives a mixture of two protonation products, Cp*Ir(2,3,4-
C6F3H2)(PMe3)(O2CMe) (5) and Cp*Ir(3,4,5-C6F3H2)(PMe3)(O2CMe) (6) in an 8:1 ratio.
Treatment of the 5/6 mixture with CF3CO2H affords 1,2,3-C6F3H3 and Cp*Ir(O2CCF3)2(PMe3)
but at dramatically different rates, with 5 reacting significantly faster than 6. Treatment of
1a with Br2, I2, or MeI gives the oxidative addition products Cp*Ir(2-C6BrF4)Br(PMe3) (7),
Cp*Ir(2-C6IF4)I(PMe3) (8), or Cp*Ir(2-C6MeF4)I(PMe3) (9), respectively. The variable-
temperature proton NMR spectra of complexes 7 and 8 reveal an unusual restricted rotation
about the Ir-PMe3 bonds on the NMR time scale (7, ∆Gq ) 39 ( 2 kJ mol-1; 8, ∆Gq ) 38 (
2 kJ mol-1). Similarly, treatment of Cp*Rh(η2-C6F4)(PMe3) (1b) with I2 leads to formation of
Cp*Rh(2-C6IF4)I(PMe3) (10), which also exhibits restricted rotation about the metal-
phosphorus bond (∆Gq ) 44 ( 2 kJ mol-1). While the tetrafluorobenzyne complex (1a ) is
unreactive toward CO, the hydrocarbon analogue Cp*Ir(η2-C6H4)(PMe3) (1c) does react to
give the CO monoinsertion product (11). Compound 1c also reacts with I2 to afford Cp*Ir(2-
C6IH4)I(PMe3) (12), which also shows restricted rotation about the Ir-PMe3 bond (∆Gq ) 43
( 2 kJ mol-1). X-ray crystal structures of complexes 3, 4, 5, 7, 8, 10, and 11 are reported.
In tr od u ction
markably unreactive, early transition metal complexes
of benzyne have been shown to undergo a rich insertion
chemistry with substrates such as alkenes, alkynes,
ketones, nitriles, CO, CO2, CS2, and even metal carbonyl
complexes.2 These insertions are often regioselective and
lead to a large variety of new metallacycles and organic
compounds. Zirconium-benzyne complexes in particular
have been used extensively in organic synthesis.7,8 Late
transition metal benzyne complexes have also been
thoroughly studied and shown to have a rich insertion
chemistry.3,9,10
There are many examples of transition metal com-
plexes containing the benzyne (η2-C6H4) ligand, and
their reaction chemistry has been studied extensively.1-4
With the exception of complexes of the type Re(η2-C6H3-
Me)(2-MeC6H4)2(PMe2R)2]+, their neutral precursors,5
and Ta(η2-C6H4)Cp(C2B4H4Et2)(PMe3),6 which are re-
* Corresponding author.
† Dartmouth College.
‡ University of Delaware.
We have described previously the syntheses and
molecular structures of tetrafluorobenzyne complexes
of iridium (1a ) and rhodium (1b) and the analogous
benzyne complex of iridium (1c).11,12 Here we report
(1) Retbøll, M.; Edwards, A. J .; Rae, A. D.; Willis, A. C.; Bennett,
M. A.; Wenger, E. J . Am. Chem. Soc. 2002, 124, 8348-8360.
(2) Bennett, M. A.; Schwemlein, H. P. Angew. Chem., Int. Ed. Engl.
1989, 28, 1296-1320.
(3) Bennett, M. A.; Wenger, E. Chem. Ber./ Recl. 1997, 130, 1029-
1042.
(4) J ones, W. M.; Klosin, J . Adv. Organomet. Chem. 1998, 42, 147-
221.
(5) Arnold, J .; Wilkinson, G.; Hussain, B.; Hursthouse, M. B.
Organometallics 1989, 8, 415-420.
(6) Houseknecht, K. L.; Stockman, K. E.; Sabat, M.; Finn, M. G.;
Grimes, R. N. J . Am. Chem. Soc. 1995, 117, 1163-1164.
(7) Buchwald, S. L.; Nielsen, R. B. Chem. Rev. 1988, 88, 1047-1058.
(8) Broene, R. D.; Buchwald, S. L. Science 1993, 261, 1696.
(9) Hartwig, J . F.; Bergman, R. G.; Andersen, R. A. J . Am. Chem.
Soc. 1991, 113, 3404-3418.
(10) Hartwig, J . F.; Andersen, R. A.; Bergman, R. G. J . Am. Chem.
Soc. 1989, 111, 2717-2719.
10.1021/om030048w CCC: $25.00 © 2003 American Chemical Society
Publication on Web 03/29/2003

Reactions of Iridium and Rhodium Complexes
Organometallics, Vol. 22, No. 10, 2003 2135
1
some examples of their reaction chemistry.
ously used H/19F HOESY spectroscopy to show that the
fluorine closer to the hydride ligand or to the PMe3
1
ligand is the one that couples more strongly to H or
31P, respectively.12 Therefore, in the major isomer 3a ,
the ortho-fluorine should be oriented toward the PMe3
ligand. Indeed, the 31P{1H} resonance of the major
isomer appears as a doublet with coupling to the ortho-
fluorine (4J PF ) 5 Hz), while that of the minor isomer
appears as a singlet. The major isomer 3a observed in
solution is also that observed in the solid state (see
below).
Resu lts a n d Discu ssion
As observed previously for other fluoroaryl(hydrido)
complexes,11,12 treatment of 3 with excess n-BuLi pro-
duces the expected trifluorobenzyne complex Cp*Ir(η2-
3,4,5-C6F3H)(PMe3) (4). The ethyl(tetramethyl)cyclo-
pentadienyl analogue of 4 has been reported previously
and shows restricted rotation about the Ir-benzyne
bond.12 Treatment of 4 with acetic acid produces a
mixture of two compounds, Cp*Ir(2,3,4-C6F3H2)(PMe3)(O2-
CMe) (5) and Cp*Ir(3,4,5-C6F3H2)(PMe3)(O2CMe) (6), in
a ratio of 8:1. Evidently, the two inequivalent ipso-
carbon atoms on the benzyne ligand are protonated at
different rates. The preference for attack at the ipso-
carbon that is ortho to the ring carbon bearing hydrogen
may be due to a difference in charge distribution on the
unsymmetrical η2-C6F3H ligand. The 19F NMR spectrum
of the minor product 6 consists of a triplet of triplets at
Transition metal benzyne complexes, particularly
those of late transition metals, such as Ni(η2-C6H4)(Cy2-
PCH2CH2PCy2)2,13 and Ru(η2-C6H4)(PMe3)4,9,10 have
been shown to undergo addition reactions with a variety
of electrophiles such as acids, alcohols, amines, CH3-
CN, H2O, I2, and MeI. In each case, addition across the
M-C(η2-benzyne) bond occurs to give an ortho-substi-
tuted phenyl complex. Only the unusual complexes [Re-
(η2-C6MeH3)(2-MeC6H4)2(PMe2R)2]+ and their neutral
precursors5 appear to be unreactive to electrophiles,
even including excess CF3SO3H.
Treatment of Cp*Ir(η2-C6F4)(PMe3) (1a ) with either
1 equiv or an excess of acetic acid produces the expected
addition product Cp*Ir(2,3,4,5-C6F4H)(PMe3)(O2CMe)
(2). Presumably, the reaction proceeds by protonation
of one of the equivalent coordinated benzyne carbon
atoms to give an aryl ring, followed by trapping of the
acetate anion by the metal center. Notably, even a large
excess of acetic acid does not cause protonation of the
Ir-aryl bond to afford free arene.
4
-171.9 ppm (3J FF ) 20.0 Hz, J FH ) 8.0 Hz), corre-
sponding to the para-fluorine atom, and a broad singlet
at -141.4 ppm, corresponding to the meta-fluorine
atoms. On cooling a solution of the 5/6 mixture in CD2-
Cl2 to -75 °C, the broad peak at -141.4 ppm broadens
further, virtually disappearing at -35 °C, and then
separates into two separate broad peaks at -141.3 and
-139.9 ppm, indicating slowing of rotation about the
Ir-C6F3H2 bond. While no attempts were made to
separate the mixture of 5 and 6 in bulk, a crystal of
pure 5 was obtained and characterized by X-ray dif-
fraction (see below).
Treatment of 2 with NaBH4 produces the analogous
hydride complex Cp*Ir(2,3,4,5-C6F4H)(PMe3)H (3). The
1H, 19F, and 31P{1H} NMR spectra of 3 are broad at room
temperature. On cooling to -40 °C, the broad reso-
nances separate into two sets of sharp resonances in a
ratio of 2.3:1, corresponding to two rotamers about the
Ir-C6F4H bond. It is of interest to note that the Ir-H
resonance in the 1H NMR spectrum of the major isomer
3a appears as a doublet coupled only to 31P (2J HP ) 35.5
Hz), while the analogous Ir-H resonance of the minor
isomer 3b appears as a doublet of doublets with an
In contrast to the lack of reactivity with acetic acid,
treatment of the 5/6 mixture with excess trifluoroacetic
acid resulted in cleavage of the Ir-aryl bonds to produce
1,2,3-C6F3H3.14 The iridium product was the bis-trifluo-
roacetate complex Cp*Ir(O2CCF3)2(PMe3), which was
isolated and characterized. Analogous treatment with
CF3CO2D resulted in formation of C6-1,2,3-F3-4-DH2 as
the major organic product (identified by three inequiva-
lent fluorine resonances in the 19F NMR spectrum. The
corresponding organic product, C6-1,2,3-F3-5-DH2, pro-
duced by reaction of the minor isomer (6) with CF3-
CO2D, was not observed by NMR, probably due to
masking by the resonances of the major organic product.
Interestingly, the relative rates of reaction of 5 and 6
with excess CF3CO2H in CD2Cl2 solution appear to be
significantly different. Within 5 min, complex 5 was
completely converted to 1,2,3-C6F3H3 and Cp*Ir(O2-
CCF3)2(PMe3), but a significant amount of 6 remained
unreacted even after 2 h. Only after about 24 h was
complex 6 completely consumed. The large difference
additional coupling to the ortho-fluorine atom (2J HP
)
4
37.5 Hz, J HF ) 12.5 Hz). This strongly suggests that,
in the minor isomer 3b, the ortho-fluorine atom on the
C6F4H ring is oriented toward the hydride ligand. In
related fluoroaryl(hydrido) complexes we have previ-
(12) Hughes, R. P.; Laritchev, R. B.; Williamson, A.; Incarvito, C.
D.; Zakharov, L. N.; Rheingold, A. L. Organometallics 2002, 21, 4873-
4885.
(13) Bennett, M. A.; Hambley, T. W.; Roberts, N. K.; Robertson, G.
B. Organometallics 1985, 4, 1992-2000.
(14) Ernst, L.; Wray, V. J . Magn. Reson. 1977, 28, 373-375.
(11) Hughes, R. P.; Williamson, A.; Sommer, R. D.; Rheingold, A.
L. J . Am. Chem. Soc. 2001, 123, 7443-7444.

2136 Organometallics, Vol. 22, No. 10, 2003
Hughes et al.
Sch em e 1
ligand. X-ray structural analysis (see below) shows this
conformation in the solid state. At room temperature,
1
the H, 19F, and 31P NMR spectra of 7a are sharp and
1
well resolved, except for the H NMR resonance corre-
sponding to the methyl groups on phosphorus, which
appears as a broad hump. Warming a CD2Cl2 solution
of 7a /7b to 35 °C results in a sharpening of the PMe3
resonance of 7a to the expected doublet of doublets (2J HP
) 10.5 Hz, 6J HF ) 1.5 Hz). The corresponding resonance
of 7b could not be observed, presumably due to overlap
with other resonances. However, on stepwise cooling to
-80 °C, the broad PMe3 resonance broadens further,
disappears into the baseline, and then reappears as
three separate resonances in a ratio of 3:3:3. Two of the
resonances appear as doublets due to coupling to 31P
and the other as a doublet of doublets due to additional
6
coupling to the ortho-fluorine (2J HP ) 9.5 Hz, J HF
)
3.5 Hz). Analogous observations of the resonances of 7b
were not possible due to the low concentration of this
isomer. These data are consistent only with slowing of
rotation about the Ir-PMe3 bond to produce three
separate environments for the methyl groups. At -80
°C, one of these environments is evidently located in
closer proximity to the ortho-fluorine atom than the
other two, resulting in a significant H-F coupling
constant, approximately 3 times larger than the site
exchange averaged coupling observed at 35 °C. There
are several reports of restricted rotation about M-P
bonds in phosphine complexes of transition metals. This
phenomenon has been observed for PMe2Ph,15-17 PPh3,18,19
20
and PEt3 ligands, but to our knowledge has not been
observed previously for PMe3. Using line shape analysis
of the spectra of 7a , the free energy of activation (∆Gq)
for rotation about the Ir-PMe3 bond was calculated to
be 39 ( 2 kJ /mol. In contrast to the behavior of the PMe3
resonance, the two Cp* resonances for 7a and 7b do not
coalesce at 35 °C, indicating a significant barrier to
rotation about the Ir-aryl bond.
The corresponding iodo complex 8 exists as only one
observable isomer, and the 31P{1H} resonance appears
as a doublet with a large P-F coupling constant (4J PF
) 38.3 Hz), indicating that the ortho-fluorine is proximal
to the PMe3 ligand, as shown and as observed in the
solid state structure of 8 (see below). The 1H NMR
spectrum of complex 8 also shows broad resonances
corresponding to the PMe3 ligand, which separate into
three separate resonances on cooling to -75 °C. The
value of ∆Gq for rotation about the Ir-PMe3 bond in 8
was calculated to be 39 ( 2 kJ /mol.
in rates may be due to the effects of π-donor fluorine
stabilization on the relative stabilities of the intermedi-
ate protonated complexes as shown in Scheme 1, as-
suming that the mechanism of arene elimination is
effectively an electrophilic aromatic substitution reac-
tion. The putative carbocation obtained from 5 has
fluorines in the ortho- and para-positions relative to the
site of protonation, while that derived from 6 has only
one stabilizing π-donor fluorine in the para-position.
This interpretation may be simplistic, as it takes into
consideration only the stability of the Wheland inter-
mediates and ignores possible differences in activation
energy barriers, but it provides a satisfying qualitative
rationale.
Treatment of 1a with Br2 or I2 affords the correspond-
ing addition products Cp*Ir(2-C6BrF4)Br(PMe3) (7) and
Cp*Ir(2-C6IF4)I(PMe3) (8). The 1H, 19F, and 31P NMR
spectra of 7 show two isomers in a ratio of 9:1 at 35 °C.
The 31P{1H} NMR spectrum of the major isomer appears
as a doublet with a large coupling to the ortho-fluorine
on the aryl ring (4J PF ) 31.7 Hz), while that of the minor
isomer appears only as a singlet. By analogy to previous
arguments (vide supra) the two isomers are rotamers
about the Ir-C6BrF5 bond, with the major isomer
corresponding to rotamer 7a , in which the ortho-fluorine
Addition of 1 equiv of I2 to the rhodium benzyne
complex Cp*Rh(η2-C6F4)(PMe3) (1b) affords the expected
addition product Cp*Rh(2-C6IF4)I(PMe3) (9). Like the
analogous iridium complex, 9 exhibits restricted rotation
(15) Lyons, L. J .; Anderson, L. L.; Crane, R. A.; Treichel, P. M.
Organometallics 1991, 10, 587-591.
(16) Deeming, A. J .; Doherty, S.; Marshall, J . E. Polyhedron 1991,
10, 1857-1864.
(17) Li, L.; Decken, A.; Sayer, B. G.; McGlinchey, M. J .; Bregaint,
P.; Thepot, J . Y.; Toupet, L.; Hamon, J . R.; Lapinte, C. Organometallics
1994, 13, 682-689.
(18) Chudek, J . A.; Hunter, G.; MacKay, R. L.; Kremminger, P.;
Schlogl, K.; Weissensteiner, W. J . Chem. Soc., Dalton Trans. 1990,
2001-2005.
(19) Chudek, J . A.; Hunter, G.; MacKay, R. L.; Farber, G.; Weis-
sensteiner, W. J . Organomet. Chem. 1989, 377, C69-C72.
(20) Crocker, C.; Goodfellow, R. J .; Gimeno, J .; Uson, R. J . Chem.
Soc., Dalton Trans. 1977, 1448-1452.
substituent is directed more closely toward the PMe3

Reactions of Iridium and Rhodium Complexes
Organometallics, Vol. 22, No. 10, 2003 2137
Ta ble 1. Cr ysta l Da ta a n d Su m m a r y of X-r a y Da ta Collection
3
4
5
7
8
10
11
formula
fw
space group
a, Å
b, Å
c, Å
C
19H26F4IrP
C19H25F3IrP
533.56
P1h
C21H29F3IrO2P
593.61
P21/n
8.5763(6)
18.8678(13)
13.7218(10)
90
92.905(2)
90
2217.6(3)
4
C19H24Br2F4IrP
711.37
P21/c
8.5001(4)
16.2603(8)
15.4398(8)
90
91.8590(10)
90
C19H24F4I2IrP
805.35
P1h
C19H24F4I2PRh
716.06
P1h
C20H28IrOP
507.59
P21/n
8.7308(6)
24.4873(16)
9.2704(6)
90
99.7860(10)
90
1953.1(2)
4
553.57
P21/c
9.3766(2)
17.2097(2)
12.5355(2)
90
95.0640(10)
90
2014.94(6)
4
8.6507(6)
9.1369(8)
12.7089(8)
90.162(5)
90.871(4)
105.362(4)
968.49(12)
2
8.4708(1)
10.0492(1)
14.0363(2)
86.016(1)
79.914(1)
71.818(1)
1117.50(2)
2
8.438(4)
10.029(5)
14.079(6)
85.748(8)
79.314(9)
72.045(7)
1113.5(8)
2
R, deg
â, deg
γ, deg
V, Å3
2132.88(18)
4
Z
D(calcd), g/cm3
abs coeff, mm-1
R(F), %a
Rw(F2), %a
temp, K
diffractometer
radiation
1.825
6.740
2.25
6.07
1.830
7.000
2.72
8.36
1.778
6.131
3.17
7.13
2.215
10.118
2.76
7.34
173(2)
Siemens P4
Mo KR 0.71073 Å
2.393
8.843
4.34
8.17
2.136
3.646
2.11
5.63
1.726
6.920
5.02
11.25
173(2)
173(2)
173(2)
173(2)
223(2)
100(2)
Quantity minimized ) Rw(F2) ) ∑[w(Fo - Fc2)2]/∑[(wFo2)2]1/2; R ) ∑∆/∑(Fo), ∆ ) |(Fo - Fc)|.
a
2
about the Rh-P bond, which can be “frozen-out” on
cooling to -75 °C. The 31P{1H} NMR spectrum appears
as a doublet of doublets due to coupling with rhodium
(1J PRh ) 142.8 Hz) and with the ortho-fluorine substitu-
ent (4J PF ) 48.9 Hz). As discussed above, the very large
P-F coupling constant corresponds to a short distance
between the two atoms. The free energy of activation
for rotation about the Rh-PMe3 bond in 9 was calcu-
lated to be 44 ( 2 kJ /mol.
isomer can be observed at -80 °C, but the decoalescence
behavior of the minor isomer could not be observed
accurately due to its low concentration. However, the
barrier to rotation about the Ir-P bond for the major
isomer was calculated by line shape analysis to be 43
( 2 kJ /mol, a value not significantly different from the
other examples described above.
In contrast to its rapid reactions with Br2 and I2,
complex 1a undergoes reaction with excess MeI only
after prolonged heating (110 °C, 84 h). The product is
the expected addition product Cp*Ir(2-C6MeF4)I(PMe3)
(10), for which only one isomer is observed. The 31P-
{1H} resonance appears as a doublet with a large P-F
coupling constant (4J PF ) 33.9 Hz). In complex 10, the
PMe3 resonance in the 1H NMR spectrum at room
temperature is sharp and well resolved into the usual
doublet of doublets, indicating a much lower barrier to
rotation about the Ir-P bond. Further NMR studies on
this complex were not performed.
Unlike most known benzyne complexes, 1a is remark-
ably inert to insertion of unsaturated molecules. Pro-
longed treatment with CO, CH2dCH2, or CH2dCHCO2-
Me at 80 °C in benzene solution does not result in any
reaction, and the starting material is recovered un-
changed. In contrast, the hydrocarbon analogue 1c does
react with CO to afford a monoinsertion product 11,
characterized spectroscopically and crystallographically.
As with its tetrafluorobenzyne analogue 1a , the hydro-
carbon complex 1c also reacts with I2 to afford an
analogous complex 12. Complex 12 exists in C6D6
solution as a 12:1 mixture of rotamers about the Ir-
aryl bond, while in CD2Cl2 solution the ratio is 5:1. In
CD2Cl2 both rotamers show restricted rotation about
their respective Ir-PMe3 bonds. The resonances for the
individual methyl groups in the PMe3 ligands of each
Cr ysta l Str u ctu r es
Details of the crystallographic determinations for
complexes 3, 4, 5, 7, 8, 10, and 11 are collected in Table
1, and ORTEP diagrams and atom labeling schemes are
illustrated in Figures 1-7. Selected distances and
angles are collected in Table 2. For the aryl complexes
3, 5, 7, 8, and 10, a set of projections viewed down the
M-C bond to the aryl ligand is provided in Figure 8.
All these compounds show the expected three-legged
piano-stool structure. All the structures contain an
ortho-fluorine on the aryl ring that is proximal to PMe3,
providing a common point of comparison in all cases.
Comparison of the structures of 3 and 5 illustrates that
replacement of the hydride ligand by acetate is not
accompanied by any significant lengthening of the Ir-
aryl bond, but does result in significant increases in the
Ir-P and Ir-Cp* centroid distances. The other notable
change is the canting of the aryl ring away from acetate
toward PMe3, with a dramatic decrease in the P-F(ortho)
distance from 3.66 to 3.26 Å, as illustrated in Figure 8.
As shown in Figure 8, the Ir and the ipso- and para-
carbons of the aryl ring are essentially eclipsed. The
degree and direction of aryl ring canting are clearly

2138 Organometallics, Vol. 22, No. 10, 2003
Hughes et al.
F igu r e 3. ORTEP plot and atom-numbering scheme for
complex 5. Ellipsoids are shown at the 30% probability
level, and H atoms are excluded for clarity.
F igu r e 1. ORTEP plot and atom-numbering scheme for
complex 3. Ellipsoids are shown at the 30% probability
level, and H atoms are excluded for clarity, except for H1.
F igu r e 4. ORTEP plot and atom-numbering scheme for
complex 7. Ellipsoids are shown at the 30% probability
level, and H atoms are excluded for clarity.
F igu r e 2. ORTEP plot and atom-numbering scheme for
complex 4. Ellipsoids are shown at the 30% probability
level, and H atoms are excluded for clarity. Selected bond
distances and angles: Ir1-C14 2.031(6), Ir1-C15 2.049(5),
Ir1-P1 2.2412(15), C14-C19 1.349(8), C14-C15 1.356(8),
C15-C16 1.332(8), C16-C17 1.393(9), C17-C18 1.348(9),
C18-C19 1.379(9): C14-Ir1-C15 38.8(2), C14-Ir1-P1
90.83(17), C15-Ir1-P1 90.60(16), C19-C14-C15 121.2(5),
C16-C15-C14 120.6(5), C15-C16-C17 119.4(5), C18-
C17-C16 119.8(5), C17-C18-C19 120.2(5), C14-C19-
C18 118.7(5).
controlled by the steric interaction between the ortho-
aryl substituent and its proximal ligand, as has previ-
ously been discussed for other fluoroaryl analogues.12
Introduction of the ortho-bromo or -iodo substituents in
complexes 7, 8, and 10 results in two significant
changes, presumably driven by the repulsive interaction
between the ortho-Br (or I) and its proximal bromo (or
iodo) ligand on the metal. The first is an even more
pronounced canting of the aryl ring toward PMe3, and
the second is a bending of the aryl such that the para-
carbon is no longer eclipsed with the metal and the ipso-
aryl carbon atom, but is displaced toward PMe3. Both
these distortions result in diminished values of the
P-F(ortho) distances to less than 3 Å, and this increased
steric congestion around the PMe3 ligand is presumably
responsible for the increased barrier to rotation about
the M-PMe3 bond observed in solution. Increased steric
F igu r e 5. ORTEP plot and atom-numbering scheme for
complex 8. Ellipsoids are shown at the 30% probability
level, and H atoms are excluded for clarity.
congestion at the metal center in these three compounds
is also revealed by slightly increased M-C(aromatic),
M-Cp* centroid, and M-P distances.
The crystal structure of the trifluorobenzyne complex
4 shows no remarkable differences from its tetrafluo-
robenzyne analogues.11,12 The ortho-fluorine is disor-
dered between the two possible positions. The structure
of the CO insertion product 11 likewise contains no
remarkable features. Selected bond distances and angles
for each compound are included in the figure captions
for these structures.

Reactions of Iridium and Rhodium Complexes
Organometallics, Vol. 22, No. 10, 2003 2139
C21H28F4IrO2P: C, 41.24; H, 4.61. Found: C, 41.61; H, 4.78.
2
1H NMR (CDCl3, 300 MHz, 21 °C): δ 1.38 (d, J HP ) 10.8 Hz,
9H, PMe3), 1.63 (d, 4J HP ) 1.8 Hz, 15H, Cp*), 7.35 (ddddd, 3J HF
4
5
4
4
) 12.4 Hz, J HF ) 9.9 Hz, J HF ) 3.1 Hz, J HF ) ∼2 Hz, J HP
) 1.2 Hz, 1H, C6F4H). 19F NMR (CDCl3, 282.2 MHz, 21 °C): δ
-165.8 (ddd, J FF ) 21 Hz, J FF ) 19 Hz, J FH ) 10 Hz,
p-C6F4H), -160.6 (ddd, 3J FF ) 30 Hz, 3J FF ) 19 Hz, 5J FH ) 3.1
Hz, m-C6F4H), -143.8 (ddd, J FF ) 21 Hz, J FF ) 14 Hz, J FH
) 12 Hz, m-C6F4H), -116.3 (dd, J FF ) 30 Hz, J FF ) 14 Hz,
o-C6F4H). 31P{1H}NMR (CDCl3, 121.4 MHz, 21 °C): δ -32.8
(PMe3).
3
3
4
3
5
3
3
5
Cp *Ir (2,3,4,5-C6F 4H)(P Me3)H (3). To a mixture of Cp*Ir-
(2,3,4,5-C6F4H)(PMe3)(O2CMe) (2, 75 mg, 0.123 mmol) and
NaBH4 (0.2 g, 5.3 mmol) was added EtOH (15 mL), and the
resultant yellow solution stirred for 1 h. The volatiles were
removed in vacuo, and the solid residue was extracted into
hexanes and filtered. Removal of solvent gave an off-white
solid. Yield: 67 mg, 98%. X-ray quality crystals were grown
by storage of a concentrated solution in hexanes at -30 °C.
Anal. Calcd for C19H26F4IrP: C, 41.22; H, 4.73. Found: C,
41.28; H, 4.80. The compound exists in solution as two
rotamers in a ratio of 2.3:1. Major rotamer 3a : 1H NMR (CD2-
Cl2, 300 MHz, -40 °C): δ -17.30 (d, 2J HP ) 35.5 Hz, 1H, IrH),
F igu r e 6. ORTEP plot and atom-numbering scheme for
complex 10. Ellipsoids are shown at the 30% probability
level, and H atoms are excluded for clarity.
2
4
1.32 (d, J HP ) 10.5 Hz, 9H, PMe3), 1.83 (d, J HP ) 1.5 Hz,
3
4
15H, Cp*), 7.10 (ddm, J HF ) 12.7 Hz, J HF ) 9.9 Hz, 1H,
C6F4H). 19F NMR (CD2Cl2, 282.2 MHz, -40 °C): δ -167.1 (ddd,
3J FF ) 22 Hz, J FF ) 19 Hz, J FH ) 10 Hz, p-C6F4H), -160.1
3
4
3
3
3
(dd, J FF ) 34 Hz, J FF ) 19 Hz, m-C6F4H), -145.2 (ddd, J FF
5
3
) 22 Hz, J FF ) 14 Hz, J FH ) 13 Hz, m-C6F4H), -112.6 (dd,
3J FF ) 34 Hz, J FF ) 14 Hz, o-C6F4H). 31P{1H}NMR (CD2Cl2,
5
4
121.4 MHz, -40 °C): δ -38.1 (d, J PF ) 5 Hz, PMe3). Minor
rotamer (3b): 1H NMR (CD2Cl2, 300 MHz, -40 °C): δ -16.54
2
4
2
(dd, J HP ) 37.5 Hz, J HF ) 12.5 Hz, 1H, IrH), 1.29 (d, J HP
)
4
10.0 Hz, 9H, PMe3), 1.83 (d, J HP ) 1.5 Hz, 15H, Cp*), 6.84
3
4
(ddm, J HF ) 12.7 Hz, J HF ) 8.9 Hz, 1H, C6F4H). 19F NMR
3
(CD2Cl2, 282.2 MHz, -40 °C): δ -167.3 (ddd, J FF ) 22 Hz,
3J FF ) 20 Hz, J FH ) 9 Hz, p-C6F4H), -159.2 (dd, J FF ) 32
4
3
F igu r e 7. ORTEP plot and atom-numbering scheme for
complex 11. Ellipsoids are shown at the 30% probability
level, and H atoms are excluded for clarity. Selected bond
distances and angles: Ir1-C11 2.064(8), Ir1-C17 2.084(8),
Ir1-P1 2.256(2), O1-C17 1.214(10), C11-C12 1.376(12),
C11-C16 1.410(12),C12-C13 1.413(14),C13-C14 1.390(15),
C14-C15 1.372(13), C15-C16 1.405(11), C16-C17
1.479(12): O1-C17-C16 128.4(8), O1-C17-Ir1 135.2(7),
C12-C11-Ir1 140.8(7), O1-C17-C16 128.4(8).
3
3
5
Hz, J FF ) 20 Hz, m-C6F4H), -145.3 (ddd, J FF ) 22 Hz, J FF
3
3
) 13 Hz, J FH ) 13 Hz, m-C6F4H), -109.1 (ddd, J FF ) 32 Hz,
5J FF ) 13 Hz, J FH ) 12.5 Hz, o-C6F4H). 31P{1H} NMR (CD2-
4
Cl2, 121.4 MHz, -40 °C): δ -35.8 (s, PMe3).
Cp *Ir (η2-3,4,5-C6F 3H)(P Me3) (4). To a solution of Cp*Ir-
(2,3,4,5-C6F4H)(PMe3)H (3, 102 mg, 0.184 mmol) in hexanes
(15 mL) at -78 °C was added a solution of n-BuLi in hexanes
(0.66 mL, 2.8 M, 1.8 mmol). The resultant yellow solution was
allowed to warm to room temperature and was stirred for 24
h to give an orange cloudy solution. Cooling in an ice-bath,
followed by addition of ca. 1 mL of MeOH, and then removal
of volatiles in vacuo gave a yellow solid, which was extracted
into hexanes and filtered. Removal of solvent from the filtrate
in vacuo gave an off-white oily solid, which was recrystallized
by slow evaporation of a hexane solution. Yield: 38 mg, 38%.
Anal. Calcd for C19H25F3IrP: C, 42.77; H, 4.72. Found: C,
42.76; H, 4.66. 1H NMR (C6D6, 300 MHz, 21 °C): δ 0.71 (d,
Exp er im en ta l Section
All reactions were performed in oven-dried glassware, using
standard Schlenk techniques, under an atmosphere of nitro-
gen, which 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 on a Varian Unity Plus 300 or 500 FT spectrometer.
1H 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 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).
Starting complexes 1a -c were prepared as described previ-
ously.11,12
Cp *Ir (2,3,4,5-C6F 4H)(P Me3)(O2CMe) (2). To a solution of
Cp*Ir(η2-C6F4)(PMe3) (1a , 194 mg, 0.352 mmol) in toluene (20
mL) was added MeCO2H (0.2 mL, 3.49 mmol). The resultant
yellow solution was allowed to stir for 1 min, and then the
solvent was removed in vacuo to afford a brown oil. A
crystalline dull yellow solid was obtained by slow evaporation
of a hexane solution. Yield: 136 mg, 63%. Anal. Calcd for
2J HP ) 10.2 Hz, 9H, PMe3), 1.68 (d, J HP ) 1.8 Hz, 15H, Cp*),
4
3
4
5
4
6.95 (dddd, J HF ) 2.8 Hz, J HF ) 3.4 Hz, J HF ) 3 Hz, J HP
)
1.2 Hz, 1H, C6F3H). 19F NMR (C6D6, 282.2 MHz, 21 °C): δ
3
3
5
-161.2 (ddd, J
) 29.0 Hz, J FF ) 10.7 Hz, J FH ) 3.4 Hz,
FF
m-C6F3H), -141.1 (d, 3J
) 29 Hz, o-C6F3H), -136.7 (dd, 3J FF
FF
) 10.7 Hz, 3J FH ) 2.8 Hz, m-C6F3H). 31P{1H}NMR (C6D6, 121.4
MHz, 21 °C): δ -37.7 (PMe3).
Cp *Ir (2,3,4-C6F 3H 2)(P Me3)(O2CMe) (5)/Cp *Ir (3,4,5-C6-
F 3H2)(P Me3)(O2CMe) (6). To a solution of Cp*Ir(η2-3,4,5-
C6F3H)(PMe3) (4, 38 mg, 0.071 mg) in toluene (5 mL) was
added MeCO2H (0.1 mL, 1.7 mmol). The yellow solution was
stirred for 20 min and then the solvent removed in vacuo to
afford a yellow oily solid. Yield: 38 mg, 92% (both isomers).
The product, which was a mixture of 5 and 6 in a ratio of 8:1,
was recrystallized by slow evaporation of a hexane solution.
Anal. Calcd for C21H29F3IrO2P: C, 42.49; H, 4.92. Found: C,
1
42.63; H, 5.05. 5: H NMR (CDCl3, 500 MHz, 21 °C): δ 1.38

2140 Organometallics, Vol. 22, No. 10, 2003
Hughes et al.
Ta ble 2. Selected Dista n ces (Å) a n d An gles (d eg) for Ar yl Com p lexes 3, 5, 7, 8, a n d 10
3
5
7
8
10
M-C(aromatic)
M-P
2.062(3)
2.2384(8)
2.067(5)
2.2822(14)
2.120(3)
2.101(4)
2.122(6)
2.112(3)
2.995(13)
2.7005(12)
1.864(5)
121.44(10)
127.11(11)
123.09(11)
95.40(9)
96.37(8)
83.87(2)
2.97
2.2887(11)
2.5522(5)
1.860(5)
121.83(12))
129.10(12)
123.29(11)
93.88(12)
94.46(12)
83.75(3)
2.2987(17)
2.7168(5)
1.864(5)
121.82(10)
127.89(10)
123.34(11)
94.61(18)
95.31(17)
83.79(5)
M-X
M-Ct(01)a
Ct(01)-M-C
Ct(01)-M-P
Ct(01)-M-X
C-M-P(1)
C-M-X
1.889(5)
126.56(11)
134.19(12)
1.846(5)
124.54(11)
130.86(11)
130.72(11)
90.58(14)
87.40(17)
77.19(11)
3.26
88.84(8)
P-M-X
P-F(ortho)b
3.66
2.99
2.97
a
b
Ct(01) ) centroid of Cp* ring. Distance from P to the proximal ortho-fluorine on the aryl ring.
F igu r e 8. Projections viewed down the M-C bond to the aryl ligand for the aryl complexes 3, 5, 7, 8, and 10. Ellipsoids
are shown at the 30% probability level, and Cp* carbon atoms, hydrogen atoms, and phosphorus methyl groups are excluded
for clarity.
2
4
(d, J HP ) 10.5 Hz, 9H, PMe3), 1.63 (d, J HP ) 2.0 Hz, 15H,
Cp*), 2.05 (s, 3H, OAc), 6.79 (dddd, 3J HF ) 10.0 Hz, 3J HH ) 8.7
Hz, 4J HF ) 7.0 Hz, 5J HF ) 2.0 Hz, 1H, m-C6H2F3), 7.33 (ddddd,
in vacuo, and the solid residue was recrystallized from CH2-
Cl2/heptane to afford orange crystals. Yield: 7 mg, 90%. Anal.
Calcd for C19H24Br2F4IrP: C, 32.08; H, 3.40. Found: C, 32.20;
H, 3.44. The compound exists in solution as a mixture of two
isomers in a ratio of 9:1 at 35 °C. Major isomer 7a : 1H NMR
3J HH ) 8.7 Hz, J HF ) 6.8 Hz, J HF ) 5.1 Hz, J HF ) 2.7 Hz,
4
4
5
4J HP ) 1.3 Hz, 1H, o-C6H2F3). 19F NMR (CDCl3, 282.2 MHz,
3
3
4
2
6
21 °C): δ -165.3 (dddd, J FF ) 28.8 Hz, J FF ) 18.1 Hz, J FH
) 7.0 Hz, 5J FH ) 2.7 Hz, m-C6F4H), -146.6 (dddd, 3J FF ) 18.1
(CD2Cl2, 500 MHz, 35 °C): δ 1.65 (dd, J HP ) 10.5 Hz, J HF )
1.5 Hz, 9H, PMe3), 1.72 (d, 4J HP ) 2.0 Hz, 15H, Cp*); (CD2Cl2,
3
4
4
2
Hz, J FH ) 10.0 Hz, J FH ) 6.8 Hz, J FF ) 4.6 Hz, p-C6F4H),
-112.8 (br, d, 3J FF ) 28.8 Hz, o-C6F4H). 31P{1H} NMR (CDCl3,
121.4 MHz, 21 °C): δ -32.0 (PMe3). 6: 1H NMR (CDCl3, 500
500 MHz, -80 °C) δ 1.25 (d, J HP ) 11 Hz, 3H, PMe), 1.63 (d,
2
4J HP ) 2.0 Hz, 15H, Cp*), 1.68 (d, J HP ) 10.5 Hz, 3H, PMe),
2
6
1.73 (dd, J HP ) 9.5 Hz, J HF ) 3.5 Hz, 3H, PMe). 19F NMR
2
3
MHz, 21 °C): δ 1.36 (d, J HP ) 10.5 Hz, 9H, PMe3), 1.58 (d,
(CD2Cl2, 470.3 MHz, 21 °C): δ -160.8 (dd, J FF ) 22.6 Hz,
4J HP ) 2.0 Hz, 15H, Cp*), 2.10 (s, 3H, OAc), 7.10 (br, t, 3J HF
)
3J FF ) 19.7 Hz, p-C6F4Br), -159.1 (dd, J FF ) 32.4 Hz, J FF
)
3
3
8 Hz, 2H, C6H2F3). 19F NMR (CDCl3, 282.2 MHz, 21 °C): δ
19.7 Hz, m-C6F4Br), -120.9 (dd, J FF ) 22.6 Hz, J FF ) 8.9
3 4
3
5
3
4
-171.9 (tt, J FF ) 20.0 Hz, J FH ) 8.0 Hz, p-C6H2F3), -141.4
(br, s, m-C6H2F3). 31P{1H}NMR (CDCl3, 121.4 MHz, 21 °C): δ
-31.5 (PMe3).
Hz, m-C6F4Br), -100.2 (ddd, J FF ) 32.4 Hz, J FP ) 31.4 Hz,
5J FF ) 8.9 Hz, o-C6F4Br). 31P{1H}NMR (CD2Cl2, 121.4 MHz,
4
21 °C): δ -36.7 (d, J PF ) 31.7 Hz, PMe3).
Rea ction of 5/6 w ith Tr iflu or oa cetic Acid . In an NMR
tube, a solution of a mixture of complexes 5 and 6, prepared
as above, was treated with a 10-fold excess of CF3CO2H.
Monitoring of the solution showed disappearance of the
resonances of 5 within 5 min, while the resonances of 6
remained for 24 h. The only organic product was 1,2,3-C6F3H3,
identified by its NMR spectrum.14 Removal of the solvent
afforded Cp*Ir(O2CCF3)2(PMe3) as a yellow solid. Anal. Calcd
for C17H24F6IrO4P: C, 32.43; H, 3.84. Found: C, 32.38; H, 3.82.
1H NMR (CD2Cl2, 300 MHz, 21 °C): δ 1.56 (d, 2J HP ) 11.1 Hz,
Minor isomer 7b: 1H NMR (CD2Cl2, 500 MHz, 35 °C): δ
4
1.70 (d, J HP ) 2.0 Hz, 15H, Cp*). PMe3 signals not observed.
19F NMR (CD2Cl2, 470.3 MHz, 21 °C): δ -158.2 (dd, J FF
)
3
3
3
28.2 Hz, J FF ) 19.3 Hz, m-C6F5), -122.5 (dd, J FF ) 22.1 Hz,
5J FF ) 8.9 Hz, m-C6F5), -94.2 (dd, J FF ) 28.2 Hz, J FF ) 8.9
Hz, o-C6F5). para-C6F4Br fluorine resonance obscured. 31P{1H}
NMR (CD2Cl2, 121.4 MHz, 21 °C): δ -40.6 (s, PMe3).
3
5
Cp *Ir (2-C6IF 4)(P Me3)I (8). To a solution of Cp*Ir(η2-C6F4)-
(PMe3) (1a , 6.6 mg, 0.012 mmol) in CD2Cl2 (0.3 mL) in an NMR
tube was added a solution of I2 (3.0 mg, 0.012 mmol) in CD2-
Cl2 (0.3 mL). A yellow solution was obtained. NMR spectro-
scopy showed quantitative conversion to the desired product.
Orange crystals were obtained by removal of solvent and
recrystallization from CH2Cl2/heptane.Anal.Calcd for C19H24I2F4-
9H, PMe3), 1.64 (d, J HP ) 2.1 Hz, 15H, Cp*). 19F NMR (CD2-
4
Cl2, 282.2 MHz, 21 °C): δ -75.3 (s, CF3). 31P{1H} NMR (CD2-
Cl2, 121.4 MHz, 21 °C): δ -14.8.
Cp *Ir (2-C6Br F 4)(P Me3)Br (7). To a solution of Cp*Ir(η2-
C6F4)(PMe3) (1a , 6.0 mg, 0.011 mmol) in CD2Cl2 (0.6 mL) was
added Br2 (0.8 µL, 0.016 mmol). The volatiles were removed
IrP: C, 28.34; H, 3.00. Found: C, 28.44; H, 2.75. 1H NMR (CD2-
4
Cl2, 500 MHz, 21 °C): δ 1.76 (br, 9H, PMe3), 1.81 (d, J HP
)

Reactions of Iridium and Rhodium Complexes
2.5 Hz, 15H, Cp*); (CD2Cl2, 500 MHz, -75 °C) δ 1.38 (d, J HP
Organometallics, Vol. 22, No. 10, 2003 2141
2
precipitate formed. The solid was filtered and crystallized from
toluene (95%). Anal. Calcd for C29H28I2IrP: C, 31.11; H, 3.85.
Found: C, 31.44; H, 3.60. The compound exists as two
rotamers about the Ir-C bond in solution. In C6D6 the ratio
is 12:1, while in CD2Cl2 it is 5:1.
2
) 10.5 Hz, 3H, PMe), 1.73 (s, br, 15H, Cp*), 1.76 (dd, J HP
)
9.5 Hz, 6J HF ) 5.5 Hz, 3H, PMe), 1.88 (2J HP ) 10 Hz, 3H, PMe).
3
19F NMR (CD2Cl2, 282.2 MHz, 21 °C): δ -162.0 (dd, J FF
)
3
3
24.8 Hz, J FF ) 19.2 Hz, p-C6F4I), -159.7 (dd, J FF ) 32.2 Hz,
3
5
1
3J FF ) 19.2 Hz, m-C6F4I), -101.7 (dd, J FF ) 24.8 Hz, J FF
)
Ma jor r ota m er : H NMR (C6D6, 500 MHz, 21 °C): δ 1.44
3
4
9.0 Hz, m-C6F4I), -96.4 (ddd, J FF ) 32.2 Hz, J FP ) 38.3 Hz,
(d, 4J HP ) 1.8 Hz, 15H, Cp*), 1.64 (d, 2J HP ) 9.9 Hz, 9H, PMe3),
5J FF ) 9.0 Hz, o-C6F4I). 31P{1H} NMR (CD2Cl2, 121.4 MHz, 21
6.49 (ddd, J HH ) 7.5 Hz, J HH ) 7.5 Hz, J HH ) 1.5 Hz, 1H,
3
3
4
4
3
3
4
°C): δ -43.2 (d, J PF ) 38.3 Hz, PMe3).
C6H4I), 6.85 (ddd, J HH ) 7.5 Hz, J HH ) 7.5 Hz, J HH ) 1.5
3 4
Cp *Rh (2-C6IF 4)(P Me3)I (9). To a solution of Cp*Rh(η2-
C6F4)(PMe3) (1b, 35 mg, 0.076 mmol) in CH2Cl2 (10 mL) was
added a solution of I2 (19 mg, 0.075 mmol) in CH2Cl2 (1 mL).
The solvent was removed in vacuo to give a purple solid. The
solid was then dissolved in toluene and passed through a
column (silica, toluene). The first, yellow band was discarded,
and the second, red band was collected. The solvent was
removed in vacuo and the residual solid recrystallized from
CH2Cl2/heptane to give purple crystals. Yield: 20 mg, 37%.
Anal. Calcd for C19H24F4I2PRh: C, 31.87; H, 3.38. Found: C,
Hz,1H, C6H4I), 7.965 (dd, J HH ) 7.5 Hz, J HH ) 1.5 Hz, 1H,
3
4
4
C6H4I), 8.83 (ddd, J HH ) 7.5 Hz, J HH ) 1.5 Hz, J HP ) 0.75
Hz, 1H, C6H4I). 31P{1H} NMR (C6D6, 202.4 MHz, 21 °C): δ
1
-49.75 (s, PMe3). H NMR (CD2Cl2, 500 MHz, 21 °C): δ 1.70
4
2
(d, J HP ) 1.8 Hz, 15H, Cp*), 1.895 (bd, J HP ) 9.9 Hz, 9H,
3
3
4
PMe3), 6.445 (ddd, J HH ) 7.5 Hz, J HH ) 7.5 Hz, J HH ) 1.5
3
3
4
Hz, 1H, C6H4I), 6.66 (ddd, J HH ) 7.5 Hz, J HH ) 7.5 Hz, J HH
3
4
) 1.5 Hz,1H, C6H4I), 7.65 (dd, J HH ) 7.5 Hz, J HH ) 1.5 Hz,
3
4
4
1H, C6H4I), 8.235 (ddd, J HH ) 7.5 Hz, J HH ) 1.5 Hz, J HP
)
0.75 Hz, 1H, C6H4I). 31P{1H} NMR (CD2Cl2, 202.4 MHz, 21
°C): δ -48.92 (s, PMe3). 1H NMR (CD2Cl2, 500 MHz, -75 °C):
1
32.01; H, 3.26. H NMR (CDCl3, 300 MHz, 21 °C): δ 1.66 (br,
d, 2J HP ) 9.6 Hz, 9H, PMe3), 1.79 (d, 4J HP ) 3.9 Hz, 15H, Cp*);
δ 1.57 (bd, J HP ) 11 Hz, 3H, PMe3), 1.87 (bd, J HP ) 9 Hz,
3H, PMe3), 1.97 (bd, J HP ) 9.5 Hz, 3H, PMe3)
Min or r ota m er : H NMR (C6D6, 500 MHz, 21 °C): δ 1.49
2
2
2
2
(CD2Cl2, 500 MHz, -75 °C) δ 1.25 (d, J HP ) 11.0 Hz, 3H,
1
PMe3), 1.68 (1H, PMe3 obscured by Cp* resonance), 1.70 (d,
2
4J HP ) 3.0 Hz, 15H, Cp*), 1.80 (d, J HP ) 10.0 Hz, 3H, PMe3).
4
(d, J HP ) 1.8 Hz, 15H, Cp*), PMe3), 6.47 (ddd, 1H, C6H4I),
3
19F NMR (CDCl3, 282.2 MHz, 21 °C): δ - 161.2 (dd, J FF
)
3
3
4
6.79 (ddd, J HH ) 7.5 Hz, J HH ) 7.5 Hz, J HH ) 1.5 Hz, 1H,
3
3
3
4
24.8 Hz, J FF ) 19.0 Hz, p-C6F5), -159.2 (dd, J FF ) 33.3 Hz,
C6H4I), 8.19 (dd, J HH ) 7.5 Hz, J HH ) 1.5 Hz, 1H, C6H4I),
due to overlap of the PMe3 resonance and one of the aryl
resonances could not be observed. 31P{1H} NMR (C6D6, 202.4
MHz, 21 °C): δ -41.55 (s, PMe3). 1H NMR (CD2Cl2, 500 MHz,
3
5
3J FF ) 19.0 Hz, m-C6F5), -101.8 (dd, J FF ) 24.8 Hz, J FF
)
3
4
9.9 Hz, m-C6F5), -94.9 (ddm, J FF ) 33.3 Hz, J FP ) 48.9 Hz,
o-C6F5). 31P{1H} NMR (CDCl3, 121.4 MHz, 21 °C): δ 0.4 (dd,
4
1J PRh ) 142.8 Hz, J PF ) 48.9 Hz, PMe3).
4
21 °C): δ 1.76 (d, J HP ) 1.8 Hz, 15H, Cp*), 6.44 (ddd, 1H,
Cp *Ir (2-C6MeF 4)(P Me3)I (10). A mixture of Cp*Ir(η2-
C6F4)(PMe3) (1a , 6.0 mg, 0.011 mmol) and MeI (0.02 mL, 0.3
mmol) in C6D6 (0.7 mL) was heated in an NMR tube at 105 °C
for 84 h. NMR spectroscopy showed quantitative conversion
to the desired product. The product was obtained in crystalline
form by removal of solvent and recrystallization from CH2Cl2/
heptane, yielding orange crystals. Anal. Calcd for C20H27F4-
IIrP: C, 34.64; H, 3.92. Found: C, 34.93; H, 3.66. 1H NMR
3
3
4
C6H4I), 6.80 (ddd, J HH ) 7.5 Hz, J HH ) 7.5 Hz, J HH ) 1.5
Hz, 1H, C6H4I), 7.22 (dm, 3J HH ) 7.5 Hz, 1H, C6H4I), 7.81 (dd,
3J HH ) 7.5 Hz, J HH ) 1.5 Hz, 1H, C6H4I), due to overlap of
4
the PMe3 resonance could not be observed. 31P{1H} NMR (CD2-
Cl2, 202.4 MHz, 21 °C): δ -40.27 (s, PMe3). 1H NMR (CD2Cl2,
500 MHz, -75 °C): δ 1.40 (bd, 2J HP ) 11 Hz, 3H, PMe3), 1.655
(bd, 2J HP ) 10 Hz, 3H, PMe3), 1.85 (bd, overlapping, 3H, PMe3).
Cr ysta llogr a p h ic Deter m in a tion s. Crystal, data collec-
tion, and refinement parameters are collected in Table 1.
Systematic absences in the diffraction data 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 syntheses, and refined by
full-matrix least-squares procedures. SADABS absorption
corrections were applied to 3 and 8, and DIFABS absorption
corrections to 4 and 5.21 All non-hydrogen atoms were refined
with anisotropic displacement coefficients, and hydrogen atoms
were treated as idealized contributions.
4
(CDCl3, 300 MHz, 21 °C): δ 1.76 (d, J HP ) 2.4 Hz, 15H, Cp*)
2
6
1.77 (dd, J HP ) 9.6 Hz, J HF ) 2.1 Hz, 9H, PMe3) 2.45 (dd,
4J HF ) 5.4 Hz, J HF ) 1.5 Hz, 3H, C6F4Me). 19F NMR (CDCl3,
5
282.2 MHz, 21 °C): δ - 165.7 (dd, 3J FF ) 21.4 Hz, 3J FF ) 19.8
3
3
Hz, p-C6F4Me), -164.0 (dd, J FF ) 32.5 Hz, J FF ) 19.8 Hz,
3
5
4
m-C6F4Me), -138.4 (ddq, J FF ) 21.4 Hz, J FF ) 10.4 Hz, J FH
) 5.4 Hz, m-C6F4Me), -106.0 (ddd, 3J FF ) 32.5 Hz, 4J FP ) 33.9
Hz, J FF ) 10.4 Hz, o-C6F4Me). 31P{1H} NMR (CDCl3, 121.4
5
4
MHz, 21 °C): δ -45.0 (d, J PF ) 33.9 Hz, PMe3).
Cp *Ir (P Me3)(C6H4CO) (11). A solution of Cp*Ir(PMe3)-
(C6H4) (1c, 22 mg (0.046 mmol) in dry toluene (10 mL) was
placed in a Schlenk flask, and the flask was evacuated and
backfilled with CO gas. The resultant pale green solution was
stirred for 2 h under reflux, during which time the color of
the solution changed to yellow. The mixture was cooled, the
solvent removed in vacuo, and the resultant solid crystallized
from dry hexanes to give X-ray quality crystals (22 mg; 95%).
Anal. Calcd for C30H28IrOP: C, 47.32; H, 5.56. Found: C, 47.12;
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 for generous financial sup-
port.
H, 5.24. IR (toluene): 1653, 1697 cm-1
.
1H NMR (C6D6, 300
2
MHz, 22 °C): δ 0.96 (d, J HP ) 9.9 Hz, 9H, PMe3), 1.74 (d,
4J HP ) 1.5 Hz, 15H, Cp*), 6.87 (m, 2H, C6H4), 7.20 (m, 2H,
C6H4). 31P{1H} NMR (C6D6, 121.4 MHz, 22 °C): δ -34.72 (s,
PMe3).
Su p p or tin g In for m a tion Ava ila ble: Atomic fractional
coordinates, bond distances and angles, and anisotropic ther-
mal parameters for complexes 3, 4, 5, 7, 8, 10, and 11 are
available free of charge via the Internet at http://pubs.acs.org.
Cp *Ir (2-C6IH4)(P Me3)I (12). To a solution of Cp*Ir(PMe3)-
(C6H4) (1c, 33 mg, 0.069 mmol) in dry hexanes (15 mL) was
added dropwise a solution of I2 (17 mg, 0.065 mmol, 0.95 equiv)
in dry hexanes (purple). An instantaneous reaction was
observed to give an orange saturated solution from which a
OM030048W
(21) Walker, N.; Stuart, D. Acta Crystallogr. Sect. A 1983, 39, 158-
166.