Mechanistic investigation of the reaction of iridium dihydride complexes with organic acid chlorides

Article abstract of DOI:10.1021/om000039c

Treatment of Cp*(PMe₃)IrH₂ (1a) with aromatic and hindered aliphatic acid chlorides ClC-(O)R in benzene in the presence of an amine (N,N,N′,N′-tetramethyldiaminonaphthalene (7), (-)-sparteine (8), or triethylamine (9)), results in the formation of Ir(III) acyl hydride complexes, Cp*(PMe₃)Ir(C(O)R)H (R = C₆H₅, 3a; p-CH₃C₆H₄, 3b; p-CNC₆H₄, 3c; p-NO₂C₆H₄, 3d; p-CF₃C₆H₄, 3e; p-FC₆H₄, 3f; p-CH₃OC₆H₄, 3g; CHMe₂, 4; CHPh₂, 5; CMe₃, 6) with the accompanying precipitation of the corresponding ammonium chloride salt. Kinetic studies revealed the formation of 3-6 to be first order in 1a and acid chloride and zero order in amine. A Hammett correlation showed that the reaction rate is increased by electron-withdrawing groups on the aromatic ring of the aroyl chloride. Changing the substituent on the iridium-bound phosphine was found to have a significant steric effect along with an unexpected electronic effect. In contrast to the reaction seen with aroyl chlorides, the reaction of 1a with monosubstituted acetyl chlorides in the presence of Proton Sponge results in the formation of vinyl chloride complexes, Cp*(PMe₃)Ir(CH=CHR)(Cl) (R = H, 15a; CH₃, 15b; C₆H₅, 15c). On the basis of the kinetic results for the formation of 3-6, the formation of both acyl hydride and vinyl chloride complexes is proposed to occur via nucleophilic attack of the metal center at the carbonyl carbon as the first step.

Full text of DOI:10.1021/om000039c

Organometallics 2000, 19, 2073-2083
2073
Mech a n istic In vestiga tion of th e Rea ction of Ir id iu m
Dih yd r id e Com p lexes w ith Or ga n ic Acid Ch lor id es
Sara N. Paisner, Peter Burger, and Robert G. Bergman*
Department of Chemistry, University of California, Berkeley, California 94720
Received J anuary 18, 2000
Treatment of Cp*(PMe3)IrH2 (1a ) with aromatic and hindered aliphatic acid chlorides ClC-
(O)R in benzene in the presence of an amine (N,N,N′,N′-tetramethyldiaminonaphthalene
(7), (-)-sparteine (8), or triethylamine (9)), results in the formation of Ir(III) acyl hydride
complexes, Cp*(PMe3)Ir(C(O)R)H (R ) C6H5, 3a ; p-CH3C6H4, 3b; p-CNC6H4, 3c; p-NO2C6H4,
3d ; p-CF3C6H4, 3e; p-FC6H4, 3f; p-CH3OC6H4, 3g; CHMe2, 4; CHPh2, 5; CMe3, 6) with the
accompanying precipitation of the corresponding ammonium chloride salt. Kinetic studies
revealed the formation of 3-6 to be first order in 1a and acid chloride and zero order in
amine. A Hammett correlation showed that the reaction rate is increased by electron-
withdrawing groups on the aromatic ring of the aroyl chloride. Changing the substituent on
the iridium-bound phosphine was found to have a significant steric effect along with an
unexpected electronic effect. In contrast to the reaction seen with aroyl chlorides, the reaction
of 1a with monosubstituted acetyl chlorides in the presence of Proton Sponge results in the
formation of vinyl chloride complexes, Cp*(PMe3)Ir(CHdCHR)(Cl) (R ) H, 15a ; CH3, 15b;
C6H5, 15c). On the basis of the kinetic results for the formation of 3-6, the formation of
both acyl hydride and vinyl chloride complexes is proposed to occur via nucleophilic attack
of the metal center at the carbonyl carbon as the first step.
In tr od u ction
have been observed.14,18-21 However, most of the com-
plexes studied were metal carbonyl anions;6-8,14,15,17-19,21
the nucleophilicity of only a few neutral, 18-electron,
organometallic complexes have been evaluated quanti-
tatively.22-24 Previous work in our group has shown that
Cp*(PMe3)IrH2 (1a ) can be deprotonated using tert-
butyllithium, and the resulting anion acts as a nucleo-
phile in many types of reactions.25,26 In this report we
describe mechanistic studies of the reaction of this
coordinatively saturated electron-rich iridium hydride
with acid chlorides in the presence of amines. In light
of our previous results, we were interested in whether
this reaction occurs via the neutral complex or the
deprotonated metal anion.
Alkylation and acylation of organometallic anions via
nucleophilic displacement is a common method for the
formation of metal-carbon bonds.1-10 In these reactions,
the transition metal complex acts as the nucleophile.
The kinetics and mechanisms of these reactions have
received much attention since formal nucleophilic attack
by a metal complex is a key step in many catalytic
processes.2,11-17
The nucleophilicities of a number of organometallic
complexes have been compiled, and large differences
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Rea ctivity of 1 w ith Ben zoyl a n d Su bstitu ted
Acetyl Ch lor ides. Syn th esis of Cp*(P Me3)Ir (C(O)R)-
(H) Com p lexes. Previously, we reported the synthesis
of the acyl hydride Cp*(PMe3)Ir(C(O)C6H5)(H) (3a ) from
(7) Brinkman, K. C.; Blakeney, A. J .; Krone-Schmidt, W.; Gladysz,
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1977, 99, 250.
(14) Pearson, R. G.; Fidore, P. E. J . Am. Chem. Soc. 1980, 102, 1541,
and references therein.
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P. H. J . Am. Chem. Soc. 1986, 108, 6219.
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(20) Helvenston, M. C.; Castro, C. E. J . Am. Chem. Soc. 1992, 114,
8490.
(21) Dessy, R. E.; Pohl, R. L.; King, R. B. J . Am. Chem. Soc. 1980,
88, 5121.
(22) Werner, H. Angew. Chem., Int. Ed. Engl. 1983, 22, 927.
(23) Herrmann, W. A.; Plank, J .; Bauer, C.; Ziegler, M. L.; Guggolz,
E.; Alt, R. Z. Anorg. Allg. Chem. 1982, 487, 85.
(24) Plank, J .; Riedel, D.; Herrmann, W. A. Angew. Chem., Int. Ed.
Engl. 1980, 19, 937.
(15) Wang, P.; Atwood, J . D. J . Am. Chem. Soc. 1992, 114, 6424.
(16) Richardson, D. E.; Christ, C. S.; Sharpe, P.; Eyler, J . R.
Organometallics 1987, 6, 1819.
(25) Peterson, T. H.; Golden, J . T.; Bergman, R. G. Organometallics
1998.
(26) Gilbert, T. M.; Bergman, R. G. J . Am. Chem. Soc. 1985, 107,
3502.
(17) Wang, R.; Atwood, J . D. Organometallics 1993, 12, 4247.
10.1021/om000039c CCC: $19.00 © 2000 American Chemical Society
Publication on Web 04/21/2000

2074 Organometallics, Vol. 19, No. 11, 2000
Paisner et al.
{Cp*(PMe3)Ir(Li)(H)}n (Cp* ) pentamethylcyclopenta-
dienyl) and benzoic acid anhydride (eq 1).25 The iridate
was synthesized by deprotonation of Cp*(PMe3)IrH2 (1a )
with t-BuLi. This method, however, gave poor yields of
compound 3a due to the difficulty of isolating the
product cleanly. To solve these problems with the
synthetic route, a new method was developed.
Figu r e 1. ORTEP diagram ofCp*(PMe3)Ir(C(O)p-CH3C6H4)-
(H) (3b). Thermal ellipsoids are shown at 50% probability
levels. Hydrogen atoms (except H32) are omitted for clarity.
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 3b
Bond Lengths
Treatment of Cp*(PMe3)IrH2 (1a )27,28 with acid chlo-
rides ClC(O)R ((R ) C6H5, 2a; p-CH3C6H4, 2b; p-CNC6H4,
2c; p-NO2C6H4, 2d ; p-CF3C6H4, 2e; p-FC6H4, 2f; p-CH3-
OC6H4, 2g; CHMe2, 2h ; CHPh2, 2i; CMe3, 2j) in benzene
in the presence of an amine (N,N,N′,N′-tetramethyl-
diaminonaphthalene (7), (-)-sparteine (8), or triethyl-
amine (9)) results in the formation of yellow or orange
complexes Cp*(PMe3)Ir(C(O)R)H (R ) C6H5, 3a ; p-
CH3C6H4, 3b; p-CNC6H4, 3c; p-NO2C6H4, 3d; p-CF3C6H4,
3e; p-FC6H4, 3f; p-CH3OC6H4, 3g; CHMe2, 4; CHPh2,
5; CMe3, 6) with the precipitation of the corresponding
ammonium chloride salt.29 A representative example is
shown in eq 2. All the products exhibit similar spectro-
scopic characteristics. The hydride resonances in the 1H
NMR spectra appear as doublets at ca. δ -16.5 ppm
(depending on the acyl group). The resonance for the
phosphine in the 31P{1H} NMR spectrum is at ca. δ -38
ppm for 3-6.
Ir(1)-P(1)
C(1)-Ir(1)
C(1)-O(1)
Ir(1)-C(101)
Ir(1)-H(32)
2.239(1)
2.016(4)
1.238(5)
2.073(8)
1.58(5)
Bond Angles
P(1)-Ir(1)-C(1)
87.4(1)
126.2(1)
120.0(3)
127(1)
C(1)-Ir(1)-C(101)
Ir(1)-C(1)-C(2)
Ir(1)-C(1)-H(32)
F igu r e 2. Plot of the disappearance of 1a with time
obtained using flooding conditions. Conditions: [1a ] ) 4.00
× 10-2 M, [7] ) 0.242 M, [2a ] ) 0.408 M. Inset: Plot of
ln[1a ] vs time. The observed rate constant ) (2.04 ( 0.1)
X-r a y Cr ysta llogr a p h ic Stu d y of 3b. To investigate
the solid-state structure of compounds 3a -g, a single-
crystal X-ray diffraction study of compound 3b, R )
p-tolyl, was performed. X-ray quality crystals of 3b were
obtained by crystallization from pentane at -40 °C. An
ORTEP diagram is shown in Figure 1, selected bond
lengths and angles are listed in Table 1, and the crystal
and data collection parameters are listed in Table 2.
Compound 3b forms as an undisordered chiral crystal,
and only one enantiomer is shown. The hydride ligand
× 10-4 s-1
.
was located and refined isotropically; the Ir-H bond
distance was determined to be 1.58 Å. The observed
three-legged piano stool geometry is common for com-
plexes of this type.
Kin etic Stu d ies of th e Rea ction of 1a w ith Ben -
zoyl Ch lor id es. To gain further insight into the mech-
anism of the reaction, the concentration of reagent 1a
and products 3a -g were monitored over the course of
the reaction by 1H NMR spectroscopy. The reaction was
performed under pseudo-first-order conditions by em-
ploying a large excess of benzoyl chloride and 7. A
typical plot of the change in concentration of 1a over
time is shown in Figure 2, along with its corresponding
ln [1a ] versus time plot. These plots indicate a clean
(27) Kang, J . W.; Moseley, K.; Maitlis, P. M. J . Am. Chem. Soc. 1969,
91, 5970.
(28) Heinekey, D. M.; Hinkle, A. S.; Close, J . D. J . Am. Chem. Soc.
1996, 118, 5353.
(29) One referee asked about the result of treating 1a with 2a in
the absence of amine. This results in formation of a complex mixture
of products, several of which we were unable to identify, but including
a small amount of 3a .

Reaction of Iridium Dihydride
Organometallics, Vol. 19, No. 11, 2000 2075
F igu r e 5. Hammett correlation for the reaction of 1a with
para-substituted benzoyl chlorides in the presence of 7.
F igu r e 3. Rate dependence on [2a ] using flooding condi-
tions for the reaction with 1a and 7 (R2 ) 0.96) with the
intercept set at zero. Inset: Same rate dependence plot
with intercept not set at zero (R2 ) 0.97).
F igu r e 6. Amines used in the kinetic study.
different p-substituted benzoyl chlorides. Rate constants
were measured for the reaction of 1 and 7 with p-
methoxybenzoyl, p-toluoyl, benzoyl, and p-fluorometh-
ylbenzoyl chlorides. Qualitative t1/2 values were mea-
sured for p-trifluoromethyl, p-cyano, and p-nitrobenzoyl
chloride as the rates of reaction of 1a with these
substrates were too fast to measure conveniently by 1H
NMR spectroscopy.31 The initial concentrations of 1, acid
chloride, and 7 were kept constant for all runs. Electron-
withdrawing substituents on the acid chloride induced
a dramatic increase in the reaction rate relative to the
reaction with benzoyl chloride. A Hammett plot (Figure
5) of the results yielded a linear correlation with a F
value of 2.42. The half-life decreased from 5 h for
p-methoxybenzoyl chloride to 20 min for p-fluorobenzoyl
chloride. The t1/2 for p-nitrobenzoyl chloride was ap-
proximately 2 min.
F igu r e 4. Rate dependence on [7] measured using flooding
conditions for the reaction with 1a and 2a .
first-order dependence of the reaction rate on the
concentration of 1a .
By measuring the reaction rate with varied (excess)
concentrations of benzoyl chloride, we found the reaction
to be first order in benzoyl chloride as well. A plot of
the pseudo-first-order rate constant versus [benzoyl
chloride] is shown in Figure 3.30 A similar study
demonstrated that the reaction is zero order in the
concentration of 7 (Figure 4). From the kinetic data, an
experimental rate law was derived (eq 3). The rate
constants derived from the kinetic runs are shown in
Table 2.
-d[1]/dt ) k1[1][acid chloride]
(3)
Dep en d en ce on Am in e Str u ctu r e. The reaction
rate was measured in the presence of several different
amines to study the dependence on amine structure. The
reaction conditions were the same as those used for the
Hammett correlation. Five different amines were stud-
ied: N,N,N′,N′-tetramethyldiaminonaphthalene (7), (-)
sparteine (8), p-phenylpyridine (9), 2,6-dimethylpyridine
(10), and triethylamine (11) (Figure 6). Due to competi-
tive formation of Cp*(PMe3)IrCl2 along with the acyl
To test for radical intermediates, the reaction was run
in the presence of 5 equiv of a radical scavenger, 9,10-
dihydroanthracene (DHA). No changes in the product
composition or the qualitative rates of reaction were
observed.
Dep en d en ce of Rea ctivity on Acid Ch lor id e
St r u ct u r e. In an effort to better understand the
electronic effects in the reaction of 1 with acid chlorides,
a Hammett correlation study was undertaken using four
(31) Due to the thermal sensitivity of the products, determination
of ∆Hq and ∆Sq for the reaction with benzoyl chloride was unsuccessful.
Running the reaction above room temperature results in side products,
(30) Data taken initially showed more scatter, leading to ambiguity
with regard to the intercept and reaction order in [2a ]. Redetermina-
tion of some of the kinetic data improved the error and the reliability
of the order in [2a ]. We are grateful to a referee for calling our attention
to this problem.
and the temperature could not be reduced enough to provide
a
temperature range large enough to ensure good accuracy in the derived
activation parameters.

2076 Organometallics, Vol. 19, No. 11, 2000
Paisner et al.
Ta ble 2. Cr ysta l a n d Da ta Collection P a r a m eter s for 3b a n d 15a
3b
15a
empirical formula
fw
cryst color, habit
cryst dimens
cryst syst
C
15H33OPIr
C15OPClIrH27
482.02
yellow, prism
523.68
pale yellow, blades
0.32 × 0.22 × 0.08 mm
monoclinic
0.20 × 0.21 × 0.07 mm
orthorhombic
lattice type
lattice params
primitive
primitive
a ) 8.6780(1) Å
b ) 11.76704(2) Å
c ) 20.2744(1) Å
â ) 91.472(1)°
V ) 2069.62(4) Å3
P21/c (No. 14)
4
a ) 11.9627(2) Å
b ) 12.8214(1) Å
c ) 11.2949(2) Å
V ) 1732.40(4) Å3
space group
Z value
Dcalc
Pna21 (No. 33)
4
1.681 g/cm3
1.848 g/cm3
936.00
F000
1032.00
µ(Mo KR)
diffractometer
radiation
65.51 cm-1
79.66 cm-1
SMART CCD
Mo KR (λ ) 0.71069 Å)
SMART CCD
Mo KR (λ ) 0.71069 Å)
graphite monochromated
60.00 mm
-96 °C
ω (0.30 deg/frame)
10.0 s/frame
graphite monochromated
60.00 mm
10.0 s per frame
ω (0.30 deg/frame)
detector position
temperature
scan type
scan rate
2θmax
52.3°
51.9°
total: 8370
no. of reflns measd
total: 10 009
unique: 3870 (Rint ) 0.029)
Lorentz-polarization absorption
(Tmax ) 0.959, Tmin ) 0.441)
direct methods (SIR92)
full-matrix least-squares
0.0300
unique: 1826 (Rint ) 0.040)
corrections
Lorentz-polarization absorption
(Tmax ) 0.86, Tmin ) 0.62)
structure solution
refinement
p-factor
direct methods (SIR92)
full-matrix least-squares
0.03
anomalous dispersion
no. observations (I > 3.00σ(I))
no. variables
reflection/param ratio
residuals: R; Rw; Rall
goodness of fit indicator
max shift/error in final cycle
max peak in final diff map
min peak in final diff map
all non-hydrogen atoms
3074
226
13.60
0.020; 0.028; 0.027
1.15
all non-hydrogen atoms
2160
162
13.33
0.020; 0.023; 0.025
0.78
0
0.02
0.47 e/ Å3
0.90 e/Å3
-1.50 e/Å3
-0.59 e/ Å3
hydride product with p-phenylpyridine and 2,6-dimeth-
ylpyridine, rate constants were not measured in these
cases. In the case of the remaining three amines, the
measured rate constants are shown in Table 2. They
were, as expected, the same within error. This is
consistent with the zero-order rate dependence of the
amine determined previously in the kinetic studies.
Ra te Dep en d en ce on P h osp h in e Str u ctu r e. The
reaction of 1a -f (Cp*(PR3)IrH2: P(CH3)3, 1a ; P(CH2-
CH2CH3)3, 1b ; P(C6H5)(CH3)2, 1c; P(p-CH3OC6H4)-
(CH3)2, 1d ; P(p-CF3C6H4)(CH3)2, 1e; P(C6H5)3, 1f) with
benzoyl chloride and 7 was studied to determine the
effect on the reaction caused by changing the steric and
electronic properties of the phosphine. Compounds 1b-f
were synthesized using a method analogous to that used
to prepare the previously reported trimethylphosphine
complex 1a (1c-e from Cp*(L)IrCl2, L ) P(C6H5)(CH3)2
(28); P(p-CH3OC6H4)(CH3)2 (29); P(p-CF3C6H4)(CH3)2
(30), respectively).27,28
electronic effects, the rates of reaction of 1d and 1e were
determined. Electron-donating groups were found to
accelerate the rate of the reaction. However, the sensi-
tivity of the rate to changes in the substituent was
substantially weaker than that observed with the acid
chlorides, and so a full Hammett study was not carried
out.
Rea ction of 1 w ith Mon osu bstitu ted Acyl Ch lo-
r id es. Syn th esis of Cp *(P Me3)Ir (CHdCHR)Cl Com -
p lexes. Treatment of 1 with three monosubstituted acyl
chlorides (ClC(O)CH2R, R ) H, 2k ; Me, 2l; Ph, 2m ) in
the presence of 7 resulted in the formation of Cp*-
(PMe3)Ir(CHdCHR)(Cl) (H, 15a ; CH3, 15b; C6H5, 15c)
(eq 4). Compounds 15a -c have been characterized using
1
The reactions were monitored by H NMR spectros-
copy and carried out under conditions identical to those
used in the Hammett study. Compounds 1f and 1b were
unreactive toward benzoyl chloride in the presence of
7. Upon heating the reaction mixture, several products
were observed in both cases; the only easily identifiable
species was Cp*(PMe3)IrCl2. As a result, rate constants
were not determined in these two cases. The compounds
1c-e yielded the corresponding acyl hydrides (Cp*(RP-
(CH3)2)Ir(C(O)Ph)(H), R ) C6H5, 12; p-CH3OC6H4, 13;
p-CF3C6H4, 14). To separate phosphine steric and
1H NMR, 31P{1H} NMR, 13C{1H} NMR, IR spectroscopy,
elemental analysis, and in the case of the parent vinyl
chloride complex, 15a , X-ray crystallography.

Reaction of Iridium Dihydride
Organometallics, Vol. 19, No. 11, 2000 2077
Discu ssion
Mech a n ism of F or m a tion of Ir id iu m Acyl Hy-
d r id e. Three possible mechanisms for the formation of
3-6 are shown in Scheme 1. The two-electron mecha-
nisms (A and B) will be discussed first. The difference
between these two possible pathways hinges on whether
nucleophilic attack by iridium on the acid chloride
occurs as the rate-determining step (mechanism A) (eq
5), or deprotonation of 1 by the amine is the rate-
determining step (mechanism B) (eq 6, 7). If the initial
step involves deprotonation of 1 by the amine, followed
by nucleophilic attack of the resulting anion 17 on the
acid chloride, the rate law must include the amine
concentration. If, however, the initial step involves
nucleophilic attack of neutral 1 on the acid chloride to
form a cationic intermediate, then the amine concentra-
tion need not be part of the rate law. The observed first-
order rate dependence on [1a ] is consistent with both
mechanisms A (eq 5) and B (eq 6, i.e., k4 . k-3).
mechanism A rate ) k1[1][ClC(O)R] if k2 . k-1 (5)
F igu r e 7. ORTEP diagram of Cp*(PMe3)Ir(CHdCH2)Cl.
Thermal ellipsoids are shown at 50% probability levels.
Hydrogen atoms (except on the vinyl moiety) are omitted
for clarity.
mechanism B rate ) k3[1][NR3] if k4 . k-3
k3[1][NR3]
(6)
rate )
if k4 not . k-3
(7)
k-3 + k4[ClC(O)R]
Complex 15a exhibits three vinyl resonances in the
1H NMR spectrum at 5.3, 6.7, and 9.1 ppm. Each proton
is split by the two other neighboring protons as well as
by the phosphorus atom at iridium. The substituted
vinyl chlorides (15b, 15c) exhibit one resonance at δ 8.5
ppm for the proton R to iridium and one resonance in
the 6 ppm region for the proton â to iridium. In the 31P-
{1H} NMR spectrum the vinyl chloride complexes show
a singlet at -30 ppm. Compounds 15b and 15c form
only the trans product, as shown by a coupling constant
of 15 Hz between the R- and â-vinylic protons. In
solution 15b and 15c exist as a mixture of rotational
isomers. A similar observation was made previously
with a (bromo)(vinyl)iridium complex.32,33
X-ray quality crystals of Cp*(PMe3)Ir(CHdCH2)(Cl)
were obtained by crystallization from pentane at -40
°C. An ORTEP diagram is shown in Figure 7, selected
bond lengths and angles are given in Table 4, and
crystal and data collection parameters are given in
Table 2. The hydrogen atoms were observed on a
difference Fourier map and included calculated positions
but were not refined. There were no unusual bond
lengths or angles in the molecule.
The absence of any change in the observed rate
constant with varying amine concentrations demon-
strates that the amine is not involved in the rate-
determining step. This rules out deprotonation as the
first step. This conclusion is also supported by the lack
of noticeable change in the observed rate upon changing
the nature of the amine. Therefore, unless electron
transfer is involved (see below), we propose that the first
step is most likely nucleophilic attack by 1 on the acid
chloride followed by fast deprotonation of the cationic
iridium intermediate by the amine (mechanism A).
Mechanism A is further supported by the observed
Hammett correlation derived from the rate constants.
A F value of 2.4 indicates substantial charge develop-
ment in the rate-determining transition state, and this
suggests that there is a charge-separated intermediate
on the reaction pathway. Electron-withdrawing p-sub-
stituents on the acid chlorides increase the electrophi-
licity at the carbonyl carbon, increasing their rate of
reaction with nucleophiles. This is consistent with an
addition-elimination type of mechanism for this reac-
tion.
Deu ter iu m In cor p or a tion Stu d ies. Reaction of 1
with acetyl chloride-d3 resulted in 40% deuterium
incorporation into the R-hydrogen position of 15a and
70% deuterium incorporation in the â-hydrogen posi-
Electr on -Tr a n sfer Mech a n ism . It is possible that
the overall formation of a metal-carbon bond between
the iridium center of 1 and the acyl group of the acid
chloride takes place by an outer-sphere electron-transfer
mechanism. This alternative is illustrated as mecha-
nism C in Scheme 2. Here it is proposed that transfer
of an electron between the starting materials is the first
step, leading to dihydride radical cation 19 and acid
chloride radical anion 20, initially as partners in a
solvent cage. At this point several reaction pathways
are possible. One is loss of Cl- from 20, followed by
collapse of the resulting radical pair to acyl dihydride
cation 23, followed by proton transfer to give 3-6. A
related alternative would involve escape from the initial
solvent cage, giving the free (presumably solvated)
1
tions (as determined by H NMR spectroscopy). In the
reaction of 1-d2 with acetyl chloride, deuterium incor-
poration was determined to be 65% in the R-hydrogen
position and 30% in the â-hydrogen positions. The
reaction of 1-d2 with acetyl chloride-d3 resulted in 15a
having 100% deuterium incorporation in all three vinyl
positions.
(32) Stoutland, P. O.; Bergman, R. G. J . Am. Chem. Soc. 1985, 107,
7, 4581.
(33) Stoutland, P. O.; Bergman, R. G. J . Am. Chem. Soc. 1988, 110,
5732.

2078 Organometallics, Vol. 19, No. 11, 2000
Paisner et al.
Ta ble 3. Kin etic Da ta a
b
iridium complex
kobs
k1
(× 102 M)
amine (M)
0.083
acid chloride (M)
(× 104 s-1
)
(× 104 M-1 s-1
)
σpara
Acid Chloride Rate Dependence
1a
1a
1a
1a
1a
1a
1a
1a
1.04
7
7
7
7
7
7
7
7
2a
2a
2a
2a
2a
2a
2a
2a
0.051
0.100
0.227
0.386
0.396
0.500
0.633
0.792
0.250 ( 0.02
0.500 ( 0.03
0.905 ( 0.04
2.09 ( 0.1
2.68 ( 0.1
3.00 ( 0.2
3.73 ( 0.2
4.89 ( 0.3
4.83
4.85
4.02
5.40
6.76
6.00
5.89
6.17
0.962
3.95
3.87
2.00
2.66
4.07
5.03
0.109
0.225
0.278
0.134
0.271
0.285
0.280
av 5.49 ( 1.2
Amine Rate Dependence
1a
1a
1a
1a
1a
1a
4.00
3.87
3.90
4.00
3.70
3.94
7
7
7
7
8
9
0.242
0.529
0.230
0.225
0.223
0.258
2a
2a
2a
2a
2a
2a
0.408
0.396
0.400
0.227
0.280
0.263
2.04 ( 0.1
2.24 ( 0.1
2.09 ( 0.1
0.905 ( 0.04
1.44 ( 0.07
1.09 ( 0.05
5.00
5.66
5.40
4.02
5.13
4.14
av 4.89 ( 0.8
Hammett Correlation
1a
1a
1a
1a
4.00
4.07
4.00
4.04
7
7
7
7
0.277
0.280
0.242
0.292
2g
0.389
0.288
0.408
0.423
0.411 ( 0.02
0.565 ( 0.03
2.04 ( 0.1
1.04 ( 0.05
1.96 ( 0.1
5.00 ( 0.2
7.23 ( 0.4
-0.27
-0.17
0
2b
2a
2f
3.06 ( 0.2
0.06
Phosphine Rate Dependence
1d
1c
1e
4.05
3.90
3.83
7
7
7
0.289
0.332
0.260
2a
2a
2a
0.396
0.362
0.392
1.06 ( 0.05
0.830 ( 0.04
0.340 ( 0.02
2.68 ( 0.1
2.29 ( 0.1
0.868 ( 0.04
-0.27
0
0.54
a
b
A detailed explanation of the kinetic runs is given in the Experimental Section. Standard deviation based on mean value.
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 15a
products (<5% detectable) were observed. It therefore
seems unlikely that free radicals are involved in this
reaction. It is more difficult to rule out a completely
solvent-caged electron-transfer process. However, we
believe that in the cases of pivaldehyde and 2,2-
diphenylacetaldehyde decarbonylation of the acyl radi-
cals derived from these acid chlorides would be fast
enough (see rate constants in previous paragraph) that
this process would compete at least to some extent with
C-M bond formation in the caged radical pair. The fact
that we see good yields of iridium acyl hydrides in these
cases argues against the involvement of an outer-sphere
electron-transfer process.
Bond Lengths
Ir(1)-Cl(1)
C(1)-Ir(1)
Ir(1)-C(101)
Ir(1)-P(1)
C(1)-C(2)
2.4256(16)
2.064(8)
1.86300(10)
2.2619(17)
1.312(12)
Bond Angles
P(1)-Ir(1)-Cl(1)
86.32(6)
122.36(4)
127.0(7)
88.0(3)
C(1)-Ir(1)-C(101)
Ir(1)-C(1)-C(2)
Cl(1)-Ir(1)-C(1)
P(1)-Ir(1)-C(101)
122.36(4)
Ra te Dep en d en ce on th e P h osp h in e. The effects
on the rate caused by changing the substituents on the
iridium-bound phosphine appear to be more complicated
than those caused by changing the substituents on the
acid chloride. Increasing the size of the alkyl group, as
in Cp*(P(CH2CH2CH3)3)IrH2 (1b), or changing to three
aryl groups, as in Cp*(P(C6H5)3)IrH2 (1f), slowed the
rate to such an extent that no reaction detectable by
1H NMR spectroscopy occurred over a period of 5 days
at 25 °C. When only one methyl group in the PMe3
ligand was replaced by phenyl, as in Cp*(P(C6H5)-
(CH3)2)IrH2 (1c), conversion to acyl hydride product was
observed, but the rate was significantly slower than that
of the parent compound 1a . Because of the substantially
different electronic properties of alkyl and aryl groups,
these results are most reasonably interpreted as a
significant steric effect. That is, attaching groups larger
than methyl to the phosphorus atom makes the iridium
center sufficiently crowded that it is difficult for it to
attack the carbonyl carbon atom of the acid chloride.
radical cation and anion. Earlier work on one-electron
reduction of acid halides34 indicates that the acid
chloride radical anion should undergo rapid loss of
chloride ion, leading to acyl radical 22. This species can
then either return to the cage or undergo decarbonyla-
tion to CO and the corresponding alkyl or aryl radical.
With R ) Ph, this process is relatively slow (kCO ) 1.5
× 10-7 s-1 (gas-phase data)),35 but when R is a tertiary
or phenyl-substituted alkyl group, it is much faster (e.g.,
for R ) t-Bu kCO ) 7 × 105 s-1 and for R ) CHPh2 kCO
) 5.3 × 106 s-1).36-38
To test for the presence of acyl or alkyl free radicals,
the reaction was run in the presence of excess radical
scavenger, 9,10-dihydroanthracene (DHA). No alkanes
or aldehydes were detected by 1H NMR spectroscopy
under these conditions, nor did the rate or product
distribution change. In the absence of DHA, no R-R
(34) Lehr, G. F.; Turro, N. J . Tetrahedron 1981, 37, 3411.
(35) Solly, R. K.; Benson, S. W. J . Am. Chem. Soc. 1971, 93, 2127.
(36) Neville, A. G.; Brown, C. E.; Rayner, D. M.; Lusztyk, J .; Ingold,
K. U. J . Am. Chem. Soc. 1991, 113, 1869.
(37) Schuh, H.; Hamilton, E. J .; Paul, H.; Fischer, H. Helv. Chim.
Acta 1974, 57, 2011.
To investigate the effect of changing the electron
density at Ir without simultaneously modifying its steric
environment, we examined the rates of reaction of 1d
and 1e, the complexes with PMe2(p-OMeC6H4) and
(38) Tsentalovich, Y. P.; Fischer, H. J . Chem. Soc., Perkin Trans. 2
1994, 729.

Reaction of Iridium Dihydride
Organometallics, Vol. 19, No. 11, 2000 2079
Sch em e 1
Sch em e 2
PMe2(p-CF3C6H4) ligands, respectively, and compared
them with that of the PMe2Ph complex 1c. Although
the p-methoxy group is resonance-donating and induc-
tively electron-withdrawing, this phosphine has been
shown to accelerate the SN2-type reactions of other
iridium complexes, and so the donating effect domi-
nates. In Vaska’s complex, replacing the para H of the
triphenylphosphine ligands with electron-donating para
substituents was found to result in a large increase in
rate of oxidative addition.39 The rate constants mea-
sured for the reaction of 1d and 1e with benzoyl chloride
showed that electron-donating groups on the phosphine
increased the rate of reaction. Although a full Hammett
study was not carried out, it was clear from the two

2080 Organometallics, Vol. 19, No. 11, 2000
Paisner et al.
substituents examined that, qualitatively, the sensitiv-
ity to p-substituents on the phosphine-aryl group is
substantially weaker than that observed with the p-
substituted acid chlorides (i.e., a low apparent F value).
In view of the effect observed in other systems, this is
a surprising result. We suggest that the iridium center
may be “soft” enough to provide sufficient polarizability
for fast SN2 substitution even when modestly electron-
withdrawing (or donating) groups are present. The
“harder” acyl carbon of the acid chloride may not be able
to adjust its electron density distribution as readily, and
so responds more strongly to substitution changes. To
our knowledge, this type of effect has not been explicitly
observed or commented upon previously. Examples of
this behavior in other systems would therefore be of
interest. Alternatively, it is possible that the small F
value is due to the physical distance between the para
substituent and the iridium center such that it has only
a small effect on the rate of reaction of 1c-e.
The proposed mechanism is quite different from that
observed in many amine-catalyzed reactions of carbonyl
compounds40,41 for which it is thought that the amine
attacks the carbonyl carbon first, forming a transient
tetrahedral intermediate. Upon displacement of the
leaving group, a quaternary acylammonium salt is
thought to form. This salt is then susceptible to attack
by a nucleophile to form the product. Once again, the
lack of rate dependence on the amine makes this an
unlikely mechanism for our system.
J ohnson42 has described the factors that determine
whether a reaction follows a nucleophilic versus a base-
catalyzed pathway. Nucleophilic attack mechanisms are
favored by good leaving groups, highly electrophilic acyl
groups, and strongly basic nucleophiles. The formation
of 3-6 seems to follow this pattern. That Cp*(P(CH3)3)-
IrH2 (1a ) can act as a Lewis base has been demonstrated
elsewhere as well. Golden, Bergman and Anderson have
shown that 1a reacts with organoaluminum complexes
to form an adduct of the form (Cp*(P(CH3)3)Ir(H)2-
(AlPh3).43 This observation supports the first step in our
mechanism. In contrast, J ones has found that Cp*-
(PMe3)RhH2 reacts with C6F6 by a pathway postulated
to involve initial deprotonation of the dihydride by F-
at elevated temperatures.44 The iridium and rhodium
systems are therefore isoelectronic and isostructural
dihydrides that exhibit alternative reactivity patterns.
P r op osed Mech a n ism for th e F or m a tion of Alk -
en yl Com p lexes 15a -c. We have less experimental
information about the mechanism of formation of alk-
enyl complexes 15a -c. However, a possible pathway for
their formation is outlined in Scheme 2. We suggest that
the first step is similar to that in the formation of 3,
resulting in the charge-separated intermediate 24. From
this intermediate two possible pathways can be imag-
ined. The Proton Sponge can either remove an iridium-
bound hydrogen to form an acyl hydride complex (4, 5),
a process that might be reversible when the RCH2 group
is relatively electron-rich, or remove a proton from the
R-carbon of the acyl group to form a vinyl enolate
intermediate (25).45 The enolate can then rearrange to
enol 26, which upon loss of water, gives a vinylidene
intermediate, 27.46 Addition of HCl from the ammonium
chloride salt across the iridium-carbon double bond
results in formation of 15a -c.
1
The hydride resonance in the H NMR spectrum at δ
-16 ppm observed during the formation of 15c has a
chemical shift similar to those of acyl complexes 3-6.
This suggests that acyl hydride formation is a side
pathway in the formation of the vinyl chloride species.
This first step is apparently reversible, as no iridium
acyl hydride product is observed in the final reaction
mixture by 1H NMR spectroscopy. Compounds 15a and
15b are likely to form by the same pathway as that
which gives 15c.
Con clu sion s
We have found that in the presence of tertiary amines
Cp*(PMe3)IrH2 reacts cleanly with aroyl and sterically
hindered aliphatic chlorides to give a series of stable
acyliridium hyrides 3-6. A detailed investigation of the
mechanism of this reaction, involving kinetics and
substituent effect studies, has been carried out. These
establish that the reaction rate is zero order in amine
concentration and so does not proceed by initial depro-
tonation of the hydride. Instead, it involves direct
nucleophilic attack of the iridium center at the carbon
atom of the acyl chloride, followed by rapid chloride loss
and subsequent deprotonation of the resulting inter-
mediate by amine. Hammett studies showed that large
changes in rate are caused by changing substituents at
the para position of substituted benzoyl chlorides, but
relatively small changes in rate are induced by modify-
ing the substituents on the iridium-bound phosphine
aryl groups. We suggest that, despite its formal +3
oxidation state, the iridium center appears to be polar-
izable (“soft”) enough to be relatively unaffected in SN2
reactions by electron-withdrawing or -donating groups
on the attached phosphine substituent.
With monosubstituted acetyl chlorides, the reaction
takes a different overall course, leading to vinyl iridium
chloride complexes 15a -c. We have obtained less
quantitative information about this reaction, but we
believe that it also proceeds by initial nucleophilic attack
of Ir on the acid chloride. In this case, however, the
product-forming step involves deprotonation at the
R-carbon of the acyl fragment, rather than at the Ir
center, leading to an Ir-substituted enolate. Proton shift,
loss of water, and addition of HCl then leads to the final
product.
Exp er im en ta l Section
Gen er a l P r oced u r es. Unless otherwise noted, all reactions
and manipulations were performed in a Vacuum Atmospheres
(39) Ugo, R.; Pasini, A.; Fusi, A.; Cenini, S. J . Am. Chem. Soc. 1972,
94, 7364.
(45) A question raised by a referee was the method by which it was
determined that 4 or 5 reacted with 7‚HCl to yield 24 and then
eventually 15. This was determined by following the formation of 15c
via1H NMR spectroscopy. Initially a hydride resonance at ca. -16 ppm,
which is suggestive of an acyl hydride complex, grows in. This
resonance subsequently disappears as the reaction goes to completion.
These observations support our mechanism.
(40) Hubbard, P.; Brittain, W. J . J . Org. Chem. 1998, 63, 677.
(41) Fersht, A. R.; J encks, W. P. J . J . Am. Chem. Soc. 1970, 92, 5432.
(42) J ohnson, S. L. Advances in Physical Organic Chemistry;
Academic Press: London, 1967; Vol. 5, pp 271-317.
(43) Golden, J . T.; Peterson, T. H.; Holland, P. L.; Bergman, R. G.;
Andersen, R. A. J . Am. Chem. Soc. 1998, 120, 223.
(44) Edelbach, B. L.; J ones, W. D. J . Am. Chem. Soc. 1997, 119,
7734.
(46) Werner, H.; Schulz, M.; Windmu¨ller, B. Organometallics 1995,
14, 3659.

Reaction of Iridium Dihydride
Organometallics, Vol. 19, No. 11, 2000 2081
recirculating inert atmosphere glovebox or using standard
Schlenk and vacuum techniques. Glassware was dried in an
oven at 150 °C before use. All 31P{1H} and 19F{1H} NMR
spectra were obtained using a Bruker AMX-400 MHz spec-
trometer (162.1 MHz for 31P{1H} spectra, 376.5 MHz for 19F-
{1H} spectra). All 1H and 13C{1H} NMR spectra were obtained
using a Bruker DRX 500 MHz spectrometer (500.1 MHz for
1H NMR spectra, 125.8 MHz for 13C{1H} NMR spectra). Unless
otherwise indicated, NMR spectra were recorded as C6D6
solutions. Coupling patterns are reported as the number of
lines observed for a particular resonance (e.g., “t” refers to an
observed three-line 1:2:1 pattern) even in cases where other
(usually smaller) coupling might have been expected to appear.
IR spectra were recorded on a Mattson Galaxy Series FTIR
3000 spectrometer as benzene solutions in a NaCl-plated
solution cell or as KBr pellets. IR frequencies are reported in
cm-1. Elemental analyses were performed at the University
of California, Berkeley Microanalytical Facility, on a Perkin-
Elmer 2400 Series II CHNO/S analyzer.
In a typical run, 1a (15.7 mg, 0.0387 mmol), the internal
standard (59.6 mg, 0.278 mmol), and 7 (9.2 mg, 0.0547 mmol)
were weighed into a 1.0 mL volumetric flask. The solids were
dissolved in approximately 0.5 mL of benzene-d6
, and to this
solution benzoyl chloride (44.8 µL, 0.386 mmol) was added via
syringe. The volumetric flask was quickly filled to the 1.0 mL
line with more benzene-d6, and a sample was transferred to a
thick-walled Pyrex NMR tube. This tube was taken out of the
glovebox, frozen in liquid N2, and sealed under vacuum. The
sealed tube was kept frozen until it was placed in the NMR
probe, after which a timed run with (in this case) a 600 s delay
between pulses was begun.
Compounds 1a -f were synthesized from IrCl3‚3H2O accord-
ing to the literature procedure.28 The synthesis of 3a is used
as a representative example for the synthesis of 3-6, and the
synthesis of 15a is used as a representative example for the
synthesis of 15a -c.
Cp *(P Me3)Ir [C(O)C6H5]H (3a ). A solution of 1a (97 mg,
0.25 mmol) in benzene (2 mL) was added to a solution of 2a
(40 mg, 0.28 mmol) and 7 (65 mg, 0.30 mmol) in benzene (5
mL). The solution immediately turned a pale yellow. After
stirring for 18 h, the bright yellow solution was filtered to
remove the amine hydrochloride salt and the solvent was
removed in vacuo to give a yellow oil. The yellow oil was
dissolved in pentane (10 mL) (or Et2O) and filtered through
SiO2 (100 mg). Removal of the solvent in vacuo afforded a
yellow powder, which was recrystallized from pentane to give
63 mg (33%) of 3a as yellow crystals. In the presence 5 equiv
of 9,10-dihydroanthracene (DHA), no changes were observed
in the yields of 3a as observed by 1H NMR spectroscopy. IR
(C6H6): 3101, 3058, 3054, 2972, 1964, 1670, 1507, 1393, 1172,
Sealed NMR tubes were prepared by attaching an NMR
tube directly to a Kontes vacuum stopcock with a Cajon
adapter and flame sealing. Reactions with gases involved
condensation of a known pressure of a gas from a bulb of
known volume into the reaction vessel at -196 °C. The
pressure was determined with an MKS Baratron gauge
attached to a high-vacuum line.
Unless otherwise noted, reagents were purchased from
commercial suppliers and used without further purification.
Silica gel (Merck, 60A, 230-400 mesh, grade 9385) was dried
in vacuo at 200 °C for 48 h. Diethyl ether and tetrahydrofuran
were distilled from sodium/benzophenone ketyl under N2.
Pentane, hexanes, benzene, and toluene were either distilled
from purple sodium/benzophenone ketyl under N2 or passed
through a column of activated alumina collected under and
sparged with N2 prior to use. Methylene chloride was either
distilled from CaH2 or passed through a column of activated
alumina collected under and sparged with N2 prior to use.
Deuterated benzene and tetrahydrofuran were distilled from
sodium/benzophenone ketyl under N2 and degassed with three
freeze-pump-thaw cycles. Deuterated methylene chloride and
chloroform were distilled from CaH2 and degassed with three
freeze-pump-thaw cycles. Trimethylphosphine and tris-(n-
propyl)phosphine were vacuum transferred from sodium. The
compounds (p-MeOC6H4)P(CH3)2 and (p-CF3C6H4)P(CH3)2 were
synthesized according to a modified literature procedure. (-)-
Sparteine was dried over 4 Å molecular sieves and degassed
with three freeze-pump-thaw cycles. Triethylamine was
dried over sodium and vacuum distilled. All acid chlorides were
distilled under N2 prior to use.
Kin etics. The reactions were analyzed by 1H NMR spec-
troscopy in benzene-d6 solution by integration of the Cp*
resonance of 1 versus the Cp* resonance of 3. All data were
collected at 301 K (standardized using ethylene glycol). One
equivalent of trimethoxybenzene relative to 1 was used as an
internal standard in all runs. Reaction progress was followed
to greater than three half-lives. The initial concentrations of
1, aryl acid chloride, and 7 were set at concentrations near
0.04, 0.4, and 0.4 M, respectively, for all runs except where
stated otherwise.
1033, 978, 849, 651, 647, 475, 433, 412 cm-1 1H NMR:
. δ
-16.28 (d, 1 H, J P-H ) 36 Hz), 1.24 (d, 9 H, J P-H ) 10 Hz),
1.76 (d, 15 H, J P-H ) 2 Hz), 7.23 (t, 1 H, J H-H ) 14 Hz), 7.29
(t, 2 H, J H-H ) 15 Hz), 8.26 (d, 2 H, J H-H ) 7 Hz). 13C{1H}
NMR: δ 10.04, 18.5 (d, J C-P ) 37 Hz), 93.7, 127.1, 128.0, 129.1,
129.8, 131.1. 31P{1H} NMR: δ -37.9. Anal. Calcd for C20H30
IrOP: C, 47.12; H, 6.0. Found: C, 47.13; H, 5.93.
-
Cp *(P Me3)Ir [C(O)-p-CH3C6H4]H (3b). Complex 1 (147
mg, 0.390 mmol), 2b (70 mg, 0.45 mmol), and 7 (97 mg, 0.45
mmol) were dissolved in benzene (6 mL). Stirring for 72 h and
workup as described above resulted in 78 mg (39%) of 3b as
yellow crystals. Using 8, yield ) 42%; using 9, yield ) 39%.
IR (KBr): 2977, 2890, 1552, 1397, 1279, 1245, 1031, 961, 876,
650, 612 cm-1 1H NMR: δ -16.26 (d, 1 H, J P-H ) 36 Hz),
.
1.26 (d, 9 H, J P-H ) 10 Hz), 1.80 (d, 15 H, J P-H ) 2 Hz), 2.11
(s, 3 H), 7.12 (d, 2 H, J H-H ) 8 Hz), 8.25 (d, 2 H, J H-H ) 8 Hz).
13C{1H} NMR: δ 10.1, 18.5 (d, J C-P ) 37 Hz), 20.9, 93.6, 114.5,
127.8, 128.0, 138.9, 151.8. 31P{1H} NMR: δ -37.8. Anal. Calcd
for C21H32IrOP: C, 48.17; H, 6.16. Found: C, 47.92; H, 6.22.
Cp *(P Me3)Ir [C(O)-p-CNC6H4]H (3c). Complex 1 (52.1 mg,
0.0138 mmol), 2c (23.2 mg, 0.140 mmol), and 7 (30.0 mg, 0.140
mmol) were dissolved in benzene (6 mL). Stirring for 1 h and
workup as described above resulted in the formation of 36 mg
(51%) of 3c as orange crystals. IR (C6H6): 3074, 3070, 2954,
2890, 2226, 2098, 1960, 1572, 1532, 1282, 1002, 957, 885, 760,
1
753, 487 cm-1. H NMR: δ -16.5 (d, 1 H, J P-H ) 36 Hz), 1.23
(d, 9 H, J P-H ) 10 Hz), 1.62 (d, 15 H, J P-H ) 2 Hz), 7.25 (d, 1
H, J H-H ) 8 Hz), 7.85 (d, 1 H, J H-H ) 8 Hz). 13C{1H} NMR: δ
10.5, 19.0 (d, J C-P ) 37 Hz,), 94.5, 113.3, 119.6, 128.7, 129.2,
131.8, CN not observed. 31P{1H} NMR: δ -37.5. Anal. Calcd
for C21H29IrNOP: C, 47.18; H, 5.49. Found: C, 47.16; H, 5.47.
Cp *(P Me3)Ir [C(O)-p -NO2C6H 4]H (3d ). Complex 1 (78.8
mg, 0.208 mmol), 2d (40.3 mg, 0.217 mmol), and 7 (49.9 mg,
0.233 mmol) were dissolved in benzene (6 mL). Stirring for 1
h and workup as above resulted in the formation of 52.7 mg
(46%) of 3d as orange crystals. IR (C6H6): 3089, 3066, 2950,
A series of reactions were conducted increasing the concen-
tration of [2a ] from 0.05 to 0.8 M acid chloride to determine
the order in acid chloride. A third series of reactions were done
in which [1a ] and [2a ] were kept constant and the concentra-
tion of [7] was increased from 0.2 to 0.5 M.
Rate constants were also measured for the reaction of 1a
and Proton Sponge with p-methoxybenzoyl, p-toluoyl, benzoyl,
and p-fluoromethylbenzoyl chlorides. Qualitative t1/2 values
were measured for p-trifluoromethyl, p-cyano, and p-nitroben-
zoyl chloride, as they were too fast to measure conveniently
2098, 1950, 1830, 1564, 1497, 1344, 1212, 1010, 995, 876, 790,
1
650, 634, 498, 430 cm-1. H NMR: δ -16.45 (d, 1 H, J P-H
)
36 Hz), 1.14 (d, 9 H, J P-H ) 10 Hz), 1.59 (s, 15 H, J P-H ) 2
Hz), 7.84 (d, 2 H, J H-H ) 8 Hz), 7.97 (d, 2 H, J H-H ) 8 Hz).
1
by H NMR at the same temperature.

2082 Organometallics, Vol. 19, No. 11, 2000
Paisner et al.
13C{1H} NMR: δ 10.5, 19.1 (d, J C-P ) 37 Hz), 94.5, 123.2,
128.7, 132.4, 148.7, 158.4. 31P{1H} NMR: δ -37.9. Anal. Calcd
for C20H29IrNO3P: C, 43.31; H, 5.27. Found: C, 43.56; H, 5.55.
Cp *(P Me3)Ir [C(O)-p-CF 3C6H4]H (3e). Complex 1 (72.2
mg, 0.191 mmol), 2e (47.1 mg, 0.225 mmol), and 7 (59.8 mg,
0.279 mmol) were dissolved in benzene (6 mL). Stirring for 48
h and workup as above resulted in the formation of 72.2 mg
(65%) of 3e as yellow crystals. IR (C6H6): 3058, 2905, 2096,
) 36 Hz), 1.19 (d, 9 H, J P-H ) 5 Hz), 1.274 (s, 9 H), 1.82 (d, 15
H, J P-H ) 2 Hz). 13C{1H} NMR: δ 11.2, 19.8 (d, J C-P ) 37
Hz), 29.9, 57.1, 94.4, 248.0. 31P{1H} NMR: δ 39.46 ppm. Anal.
Calcd for C18H34IrOP: C, 44.15; H, 7.00. Found: C, 44.17; H,
7.40.
Cp *(P Me3)Ir (Cl)(CHCH2) (15a ). Complex 1 (99.3 mg,
0.245 mmol), 2k (22.1 mg, 0.281 mmol), and 7 (62.3 mg, 0.291
mmol) were dissolved in benzene (6 mL). Upon stirring for 18
h the solvent was removed in vacuo to give a yellow oil. The
yellow oil was dissolved in pentane (10 mL) and filtered
through SiO2 (100 mg). Removal of the solvent in vacuo
afforded a yellow powder, which was recrystallized from
pentane. This resulted in the formation of 69.6 mg (61%) of
15a as yellow crystals. IR: 2903, 2099, 1603, 1573, 1555, 1455,
1564, 1482, 1322, 1124, 1002, 980, 860, 720, 490 cm-1
.
1H
NMR: δ -16.35 (d, 1 H, J P-H ) 36 Hz), 1.25 (d, 6 H, J P-H
)
10 Hz), 1.67 (s, 15 H, J P-H ) 1 Hz), 7.52 (d, 1 H, J H-H ) 8 Hz),
8.08 (d, 1 H, J H-H ) 8 Hz). 13C{1H} NMR: δ 9.9, 18.4 (d, J C-P
) 37 Hz), 93.7, 113.5, 124.2, 124.5, 127.5, 128.8, 131.1. 31P-
{1H} NMR: δ -37.8. 19F{1H} NMR: δ -61.8. Anal. Calcd for
C
21H29IrOPF3: C, 43.67; H, 5.06. Found: C, 43.71; H, 5.28.
1414, 1278, 1144 cm-1 1H NMR: δ 1.19 (d, 9 H, J P-H ) 11
.
Hz), 1.48 (d, 15 H, J P-H ) 2 Hz), 5.36 (ddd, 1 H, J H-H ) 15
Hz, J H-H ) 10 Hz, J H-P ) 2 Hz), 6.68 (ddd, J H-H ) 15 Hz,
Cp *(P Me3)Ir [C(O)-p-F C6H4]H (3f). Complex 1 (93.1 mg,
0.247 mmol), 2f (45.3 mg, 0.286 mmol), and 7 (58.4 mg, 0.273
mmol) were dissolved in benzene (6 mL). Stirring for 72 h and
workup as above resulted in the formation of 69.8 mg (54%)
of 3f as yellow crystals. IR (C6H6): 3117 (s), 3058 (s), 2902
(w), 2101 (w), 1822 (d), 1594 (s), 1561 (s), 1488 (s), 1095, 987,
J H-H ) 10 Hz, J H-P ) 2 Hz), 9.11 (ddd, J H-H ) 15 Hz, J H-H
)
10 Hz, J H-P ) 1 Hz). 13C{1H} NMR: δ 9.3, 13.9 (d, J C-P ) 37
Hz), 92.6, 118.4, 145.4. 31P{1H} NMR: δ -30.8. Anal. Calcd
for C15H27ClIrP: C, 38.66; H, 5.84. Found: C, 38.82; H, 6.09.
Cp *(P Me3)Ir (Cl)(CHCHCH3) (15b). Complex 1 (80.6 mg,
0.199 mmol), 2l (23.4 mg, 0.253 mmol), and 7 (46.5 mg, 0.217
mmol) were dissolved in benzene (5 mL). Stirring for 18 h and
workup as above resulted in the formation of 44.9 mg (47%)
of rotational isomers of 15b as yellow crystals (major:minor,
4:1). IR (both isomers): 2959, 2914, 2844, 1584, 1446, 1377,
1
964, 896, 653, 627, 598, 483 (s) cm-1. H NMR: δ -16.36 (d,
1 H, J P-H ) 36 Hz), 1.22 (d, 9 H, J P-H ) 11 Hz), 1.74 (s, 15 H,
J P-H ) 1 Hz), 6.92 (t, 2 H, J H-H ) 17 Hz), 8.17 (t, 2 H, J H-H
)
14 Hz). 13C{1H} NMR: δ 10.0, 18.4 (d, J C-P ) 37 Hz), 93.5,
113.5, 127.5, 128.0, 129.5, 131.1. 31P{1H} NMR: δ -37.8. 19F-
{1H} NMR: δ -113. Anal. Calcd for C20H29IrOPF: C, 45.53;
H, 5.54. Found: C, 45.20; H, 5.74.
1278, 1210, 1152, 1073, 1209, 957, 855, 734, 681, 616 cm-1
.
1H NMR major isomer: δ 1.19 (d, 9 H, J P-H ) 11 Hz), 1.49 (d,
15 H, J P-H ) 2 Hz), 2.06 (d, 3 H, J H-H ) 6 Hz), 5.43 (m, 1 H),
8.25 (d, 1 H, J H-H ) 12 Hz); minor isomer: δ 1.25 (d, 9 H,
J P-H ) 11 Hz), 1.51 (d, 15 H, J P-H ) 2 Hz), 1.75 (d, 3 H, J H-H
) 5 Hz), 6.81 (m, 1 H), 8.35 (m, 1 H). 13C{1H} NMR δ major
and minor isomers: 9.3, 9.5, 14.0 (d, J C-P ) 37 Hz), 14.3 (d,
J C-P ) 37 Hz), 25.39, 25.40 92.40, 92.53, 126.6, 132.8 ppm.
31P{1H} NMR major isomer: δ -30.7; minor isomer: δ -34.6
ppm. Anal. Calcd for C11H29IrPCl: C, 40.03; H, 6.09. Found:
C, 39.93; H, 6.22.
Cp *(P Me3)Ir [C(O)-p-OCH3 C6H4]H (3g). Complex 1 (72.3
mg, 0.192 mmol), 2g (34.9 mg, 0.205 mmol), and 7 (44.9 mg,
0.210 mmol) were dissolved in benzene (6 mL). Stirring for 5
days and workup as above resulted in the formation of 72.3
mg (70%) of 3g as yellow crystals. IR (C6H6): 2977, 2901, 2101,
1829, 1581, 1552, 1522, 1495, 1182, 1002, 879, 728, 708, 654,
598, 476 cm-1. 1H NMR: δ -16.29 (d, 1 H, J P-H )36 Hz), 1.27
(d, 9 H, J P-H ) 10 Hz), 1.82 (s, 15 H, J P-H ) 2 Hz), 3.30 (s, 3
H), 6.37 (d, 2 H, J H-H ) 9 Hz), 7.85 (d, 2 H, J H-H ) 9 Hz).
13C{1H} NMR: δ 10.7, 19.2 (d, J C-P ) 37 Hz), 55.1, 94.2, 112.8,
128.7, 131.8, 148.0, 161.9. 31P{1H} NMR: δ -37.7. Anal. Calcd
for C21H32IrO2P: C, 46.74; H, 5.98. Found: C, 47.13; H, 6.23.
Cp *(P Me3)Ir [C(O)CHMe2]H (4). Complex 1 (80.9 mg,
0.199 mmol), 2h (19.8 mg, 0.186 mmol), and 7 (45.7 mg, 0.213
mmol) were dissolved in benzene (6 mL). Stirring for 48 h and
workup as above resulted in the formation of 52.5 mg (59%)
of 4 as yellow crystals. Compounds 4 decomposed at ambient
temperature over 24 h. IR (KBr): 2959, 2909, 2857, 2093, 1591,
1459, 1419, 1378, 1277, 1069, 1029, 959, 927, 841, 769, 728,
Cp *(P Me3)Ir (Cl)(CHCHC6H5) (15c). Complex 1 (89.0 mg,
0.219 mmol), 2m (44.1 mg, 0.285 mmol), and 7 (51.7 mg, 0.241
mmol) were dissolved in benzene (7 mL). Stirring for 18 h and
workup as above resulted in the formation of 77.1 mg (65%)
of 15c as yellow crystals. IR: 2959, 2917, 1594, 1579, 1552,
1483, 1441, 1373, 1278, 1168, 1071, 1028, 973, 953, 849, 814,
1
746, 733, 695, 677, 610, 543, 502, 467 cm-1. H NMR: δ 1.14
(d, 9 H, J P-H ) 11 Hz), 1.49 (d, 15 H, J P-H ) 2 Hz), 6.63 (dd,
1 H, J H-H ) 17 Hz, J P-H ) 3 Hz), 7.04 (t, 1 H, J H-H ) 7 Hz),
7.23 (t, 2 H, J H-H ) 7.5 Hz), 7.46 (d, 2H, J H-H ) 7 Hz), 9.63
(dd, 1 H, J H-H ) 17 Hz, J P-H ) 2 Hz). 13C{1H} NMR (C6D6):
δ 9.3, 14.1 (d, J C-P ) 37 Hz), 92.9, 125.2, 125.4, 129.1, 134.7,
139.6, 143.7. 31P{1H} NMR (C6D6): δ -30.17. Anal. Calcd for
1
679, 637 cm-1. H NMR: δ -17.0 (d, 1 H, J P-H ) 36 Hz), 1.17
(d, 3 H, J H-H ) 7 Hz), 1.21 (d, 9 H, J P-H ) 10 Hz), 1.25 (d, 3
H, J H-H ) 7 Hz), 1.85 (d, 15 H, J P-H ) 2 Hz), 3.00 (m, 1 H).
13C{1H} NMR: δ 10.9, 19.2 (d, J C-P ) 37 Hz), 19.5, 19.8, 64.9,
94.6, 226.6. 31P{1H} NMR: δ -39.4. FAB ES MS Calcd for
C
16H31PIrCl: C, 46.53; H, 5.76. Found: C, 46.21; H, 6.12.
C
17H32OP193Ir+7Li: 481.1962. Found: 481.1957.
Cp *(P P h Me2)Ir Cl2 (28). To a red/orange solution of
Cp *(P Me3)Ir [C(O)CHP h 2]H (5). Complex 1 (99.0 mg,
[Cp*IrCl2]2 (1.01 g, 1.26 mmol) in CH2Cl2 (75 mL, sparged with
N2) was added P(C6H5)(CH3)2 (0.21 mL, 1.47 mmol) via syringe
to give a bright orange solution. After stirring for 18 h, the
solvent was removed in vacuo to give an orange powder. This
powder was passed through a SiO2 column with Et2O/CH2Cl2
(3:1) as the eluent. The solvent was removed in vacuo to give
1.13 g (83%) of the product as an orange powder. IR: 2983,
2914, 1434, 1106, 1034, 951, 912, 847, 760, 720, 701, 492, 438
0.244 mmol), 2i (56.8 mg, 0.246 mmol), and 7 (54.2 mg, 0.253
mmol) were dissolved in benzene (5 mL). Stirring for 24 h and
workup as above resulted in the formation of 99.1 mg (68%)
of 5 as yellow crystals. IR: 2096, 1602, 1498, 1447, 1419, 1203,
1
1169, 1084, 1030, 939, 852, 797, 730, 703, 678, 607 cm-1. H
NMR: δ -16.7 (d, 1 H, J P-H ) 36 Hz), 1.07 (d, 9 H, J P-H ) 10
Hz), 1.70 (d, 15 H, J P-H ) 2 Hz), 5.95 (s, 1 H). 13C{1H} NMR:
δ 10.8, 20.7 (d, J C-P ) 37 Hz), 90.4, 93.6, 125.5, 125.8, 128.9,
129.4, 142.3. 31P{1H} NMR (C6D6): δ -39.75. Anal. Calcd for
23H36PIrO: C, 54.16; H, 5.89. Found: C, 53.93; H, 6.23.
Cp *(P Me3)Ir [C(O)-ter t-C4H9]H (6). Complex 1 (101 mg,
0.248 mmol), 2j (35.9 mg, 0.297 mmol), and 7 (65.4 mg, 0.305
mmol) were dissolved in benzene (6 mL). Stirring for 18 h and
workup as above resulted in the formation of 61.3 mg (51%)
of 6 as yellow crystals. IR: 2975, 2943, 2902, 2085, 1573, 1479,
1453, 1418, 1375, 1349, 1280, 1027, 955, 938, 888, 855, 800,
762, 728, 681, 668, 612 cm-1. 1H NMR: δ -17.00 (d, 1 H, J P-H
1
cm-1. H NMR (CD2Cl2): δ 1.42 (d, 15 H, J P-H ) 2 Hz), 1.86
(d, 6 H, J P-H ) 11 Hz), 7.44 (m, 3 H; meta and para positions
are overlapped), 7.65 (m, 2 H). 13C{1H} NMR (C6D6): δ 8.6,
12.86 (d, J C-P ) 40 Hz), 91.3, 130.5, 131.0, 131.6, 131.7. 31P-
{1H} NMR (C6D6): δ -19.66. Anal. Calcd for C13H26PIrCl2: C,
40.30; H, 4.88. Found: C, 40.42; H, 5.17.
Cp *(P P h Me2)Ir H2 (1c). Cp*PhMe2IrCl2 (1.02 g, 1.80 mmol)
was treated with Zn powder (3.20 g, 48.9 mmol) and acetic
acid (2.5 mL, 43.4 mol) in methanol (100 mL, N2 sparged) as
described previously for the preparation for 1a to give 852 mg
C

Reaction of Iridium Dihydride
Organometallics, Vol. 19, No. 11, 2000 2083
(96%) of 1c as a tan oil. IR: 2972, 2905, 2089, 1476, 1434,
55.1, 94.5, 113.4, 114.1, 127.8, 129.9, 130.0, 133.2, 134.5, 155.5,
161.5. 31P{1H} NMR: δ -23.62. Anal. Calcd for C26H34IrOP:
C, 51.90; H, 5.69. Found: C, 51.62; H, 5.74.
1
1379, 1277, 1101, 937, 909, 842, 720, 696, 493, 461 cm-1. H
NMR: δ -17.14 (d, 1 H, J P-H ) 32 Hz), 1.64 (d, 6 H, J P-H
)
10 Hz), 1.99, (d, 15 H, J P-H ) 1 Hz), 7.05 (t, 1 H, J H-H ) 7
Hz), 7.15 (t, 2 H, J H-H ) 7 Hz), 7.59 (dd, 2 H, J H-H ) 8 Hz,
J P-H ) 8 Hz). 13C{1H} NMR: δ 11.6, 24.7 (d, J C-P ) 40 Hz),
92.0, 129.4, 130.1, 131.6, 131.7 ppm. 31P{1H} NMR: δ -25.83
ppm. Anal. Calcd for C18H28PIr: C, 46.23; H, 6.04. Found: C,
46.32; H, 6.31.
Cp *[(p-CF 3C6H4)P (CH3)2]Ir Cl2 (30). To a red/orange solu-
tion of [Cp*IrCl2]2 (523 mg, 0.657 mmol) in CH2Cl2 (80 mL,
sparged with N2) was added (p-CF3C6H4)P(CH3)2 (289 mg, 1.40
mmol) via syringe to give a bright orange solution. After
stirring for 18 h, the solvent was removed in vacuo to give an
orange powder. This powder was passed through a column
with Et2O/CH2Cl2 (3:1) as the eluent. The solvent was removed
in vacuo to give 559 mg (70%) of the product as an orange
powder. IR: 3056, 2982, 2920, 1609, 1503, 1450, 1397, 1377,
1325, 1280, 1167, 1128, 1061, 1029, 1016, 948, 918, 842, 747,
Cp *(P P h Me2)Ir (C(O)P h )(H) (12). Cp*(PPhMe2)IrH2 (91.4
mg, 0.195 mmol), benzoyl chloride (23.0 uL, 0.198 mmol), and
7 (41.8 mg, 0.195 mmol) were dissolved in benzene (5 mL).
Stirring for 4 days and workup as described for the acyl
hydrides above resulted in 43 mg (39%) of 12 as yellow
crystals. IR (C6H6): 2968, 2907, 2156, 2096, 1540, 1477, 1432,
1
712, 691, 600, 506, 492, 450, 418 cm-1. H NMR (CD2Cl2): δ
1.45 (d, 15 H, J P-H ) 3 Hz), 1.91 (d, 9 H, J P-H ) 12 Hz), 7.72
(d, 2 H, J H-H ) 8 Hz), 7.95 (t, 2 H, J P-H ) 18.5 Hz, J H-H ) 8
Hz). 13C{1H} NMR: δ 8.7, 12.7 (J C-P ) 40 Hz), 92.1, 125.6,
131.9, 132.0, 134.3, 140.1. 31P{1H} NMR: δ -16.4. 19F{1H}
NMR: δ -61.7. Anal. Calcd for C19H25F3PCl2Ir: C, 37.75; H,
4.17. Found: C, 37.78; H, 4.16.
Cp *[(p- CF 3C6H4)P (CH 3)2]Ir H 2 (1e). Cp*[(p-CF3C6H4)P-
(CH3)2]IrCl2 (539 mg, 0.893 mmol) was treated with Zn powder
(1.77 g, 26.6 mmol) and acetic acid (1.2 mL, 20.8 mol) in
methanol (60 mL, sparged) using the same procedure as
described previously for the preparation of 1a to give 308 mg
(65%) of 1e as a tan powder. IR: 2964, 2905, 2096, 1609, 1471,
1394, 1325, 1165, 1121, 1061, 1016, 944, 916, 848, 824, 715,
691, 598, 505, 494, 431, 415 cm-1. 1H NMR: δ -17.13 (d, 1 H,
J P-H ) 32 Hz), 1.55 (d, 9 H, J P-H ) 10 hz), 7.38 (d, 2 H, J H-H
) 8 Hz), 7.45 (t, 2 H, J P-H ) 18 Hz, J H-H ) 9 Hz). 13C{1H}
NMR: δ 11.5, 24.2 (d, J C-P ) 49 Hz), 92.2 (d, J C-P ) 5 Hz),
124.8, 131.7, 132.1, 142.1, 146.3. 31P{1H} NMR: δ -25.2. 19F-
{1H} NMR: δ -62.2. Anal. Calcd for C19H27F3IrP: C, 42.61;
H, 5.08. Found: C, 42.99; H, 5.32.
1379, 1105, 1071, 1027, 942, 914, 879, 744, 693, 494, 439 cm-1
.
1H NMR: δ -15.85, (1 H, d, J P-H ) 40 Hz), 1.40 (3 H, d, J P-H
) 11 Hz), 1.61 (15 H, d, J P-H ) 2 Hz), 1.71 (3 H, d, J P-H ) 11
Hz), 7.02 (1 H, td, J H-H ) 8 Hz, J P-H ) 2 Hz), 7.11 (2 Hz, td,
J H-H ) 8 Hz, J P-H ) 2 Hz), 7.213 (1 H, t, J H-H ) 8 Hz), 7.31
(2 H, t, J H-H ) 8 Hz), 7.53 (2 H, td, J H-H ) 7 Hz, J P-H ) 3
Hz), 8.29 (2 H, d, J H-H ) 7 Hz). 13C{1H} NMR: δ 10.2, 14.6 (d,
J C-P ) 37 Hz), 22.4 (d, J C-P ) 39 Hz), 94.5, 127.8, 129.7 (d,
J C-P ) 3 Hz), 129.9, 130.0, 131.5 (d, J C-P ) 10 Hz), 132.5,
138.0, 138.4, 155.3. 31P{1H} NMR: δ -21.90. Anal. Calcd for
C
25H32IrOP: C, 52.52; H, 5.64. Found: C, 52.40; H, 5.60.
Cp *[(p-MeOC6H4)P (CH3)2]Ir Cl2 (29). To a red/orange
solution of [Cp*IrCl2]2 (505 mg, 0.634 mmol) in CH2Cl2 (80 mL,
sparged with N2) was added (p-MeOC6H4)P(CH3)2 (242 mg,
1.44 mmol) via syringe to give a bright orange solution. After
stirring for 18 h, the solvent was removed in vacuo to give an
orange powder. This powder was passed through a SiO2
column with Et2O/CH2Cl2 (3:1) as the eluent. The solvent was
removed in vacuo to give 551 mg (77%) of the product as an
orange powder. IR: 2980, 2915, 1593, 1506, 1462, 1412, 1376,
1290, 1250, 1194, 1110, 1023, 942, 913, 844, 704, 620, 538,
Cp *[(p- CF 3C6H4)P (CH3)2]Ir [C(O)P h ](H) (14). Cp*[(p-
CF3C6H4)P(CH3)2]IrH2 (97.8 mg, 0.183 mmol), benzoyl chloride
(30.1 µL, 0.258 mmol), and 7 (49.0 mg, 0.229 mmol) were
dissolved in benzene (6 mL). After stirring for 4 days, 68 mg
(57%) of 14 as yellow crystals was observed. IR (KBr): 3468,
3072, 2975, 2911, 2085, 1593, 1555, 1440, 1394, 1288, 1169,
1147, 1124, 1061, 1014, 940, 915, 878, 843, 825, 747, 730, 712,
494, 425 cm-1 1H NMR (CD2Cl2): δ 1.43 (d, 15 H, J P-H ) 2
.
Hz), 1.80 (d, 6 H, J P-H ) 16 Hz), 3.81 (s, 3 H), 6.95 (dd, 2 H,
J H-H ) 7 Hz, J P-H ) 2 Hz), 7.67 (dd, 2 H, J H-H ) 11 Hz, J P-H
) 9 Hz). 13C{1H} NMR: δ 8.1, 12.6 (d, J C-P ) 40 Hz), 55.2,
91.2, 113.7, 125.4, 132.5, 161.4 ppm. 31P{1H} NMR: δ -17.80.
Anal. Calcd for C19H28Cl2IrOP: C, 20.28; H, 4.98. Found: C,
40.46; H, 5.26.
692, 667, 625, 598, 506, 488, 407 cm-1
.
1H NMR: δ -15.90
) 10 Hz), 1.53 (15H,
(1H, d, J P-H ) 40 Hz), 1.33 (3H, d, J
P-H
d, J
) 2 Hz), 1.60 (3H, d, J
) 11 Hz), 7.21 (1H, tt, J
P-H
P-H
Cp *[(p-MeOC6H4)P (CH3)2]Ir H2 (1d ). Cp*[(p-MeOC6H4)P-
(CH3)2]IrCl2 (566 mg, 0.876 mmol) was treated with Zn powder
(1.60 g, 24.5 mmol) and acetic acid (1.2 mL, 20.8 mol) in
methanol (60 mL, sparged) using the same procedure as
described previously for the preparation of 1a to give 425 mg
(97%) of 1d as a tan oil. IR: 3426, 2919, 2081, 1595, 1499,
1289, 1250, 1179, 1100, 1031, 910, 826, 710, 527, 440, 404
cm-1. 1H NMR: δ -17. 13 (d, 1 H, J P-H ) 40 Hz), 1.68 (d, 6 H,
J P-H ) 16 Hz), 2.05 (d, 15 H, J P-H ) 2 Hz), 3.25 (s, 3 H), 6.80
(dd, 2 H, J H-H ) 8 Hz, J P-H ) 2 Hz), 7.60 (dd, 2 H, J H-H ) 12
) 7 Hz, J
) 2 Hz), 7.303 1H, (td, J
) 8 Hz, J
H-H P-H
H-H
P-H
) 2 Hz), 7.37 (1H, d, J
) 8 Hz), 7.46 (1H, t, J
) 9 Hz),
H-H
H-H
8.23 (1H, dd, J
) 9 Hz, J
) 2 Hz). 13C{1H} NMR: δ
H-H
P-H
10.1, 14.9 (d, J C-P ) 37 Hz), 22.1 (d, J C-P ) 38 Hz), 94.6, 124.9
(m), 125.0, 127.9, 129.8, 130.2 (d, J C-P ) 13 Hz), 131.8 (d, J C-P
) 40 Hz), 131.9 (d, J C-F ) 64 Hz), 142.6, 143.0, 154.9. 31P{1H}
NMR: δ -21.6, 19F{1H} NMR: δ -62.3. Anal. Calcd for
C
26H31F3IrOP: C, 48.82; H, 4.88. Found: C, 48.60; H, 4.99.
Hz, J P-H ) 8 Hz) ppm. 13C{1H} NMR: δ 10.9, 24.4 (d, J C-P
)
Ack n ow led gm en t. We are grateful to the National
40 Hz), 54.3, 91.2, 112.9, 132.5, 132.6, 160.5 ppm. 31P{1H}
NMR: δ -27.3 ppm. Anal. Calcd for C19H30IrOP: C, 45.86; H,
6.08. Found: C, 46.09; H, 6.28.
Science Foundation (Grant No. CHE-9633374) and the
J ohn Simon Guggenheim Memorial Foundation for
generous financial support. The authors would also like
to thank Dr. Frederick Hollander, director of the UC
Berkeley College of Chemistry X-ray Diffraction Facility
(CHEXRAY) for carrying out the crystallographic de-
terminations and Dr. Hans F. Luecke for helpful dis-
cussions.
Cp *[(p-MeOC6H4)P (CH3)2]Ir [C(O)P h ](H) (13). Cp*[(p-
MeOC6H4)P(CH3)2]IrH2 (102 mg, 0.204 mmol), benzoyl chloride
(30.1 mg, 0.214 mmol), and 7 (44.2 mg, 0.206 mmol) were
dissolved in benzene (6 mL). Stirring for 7 days and workup
as described above resulted in the formation of 82.1 mg (67%)
of 13 as yellow crystals. IR: 3449, 3070, 2972, 2909, 2081,
1593, 1555, 1498, 1289, 1247, 1180, 1145, 1105, 1026, 940, 915,
Su p p or tin g In for m a tion Ava ila ble: Data collection and
refinement details and listings of atomic coordinates, thermal
parameters, bond lengths, and bond angles of both crystallo-
graphically characterized complexes and assignments of 13C-
{1H} NMR spectroscopic data. This material is available free
of charge via the Internet at http://pubs.acs.org.
1
878, 830, 799, 755, 688, 646, 529, 493, 433 cm-1. H NMR: δ
-15.80 (d, 1 H, J P-H) 40 Hz), 1.40 (3 H, d, J P-H ) 11 Hz),
1.63 (15 H, d, J P-H ) 2 Hz), 1.68 (3 H, d, J P-H ) 11 Hz), 3.23
(3 H, s), 6.74 (dd, 2 H, J H-H ) 9 Hz, J P-H ) 1 Hz), 7.18 (1 H,
t, J H-H ) 8 Hz), 7.28 (2 H, t, J H-H ) 8 Hz), 7.50 (2 H, td, J H-H
) 9 Hz, J P-H ) 2 Hz), 8.27 (2 H, d, J H-H ) 7 Hz). 13C{1H}
NMR: δ 10.3, 15.6 (d, J C-P ) 37 Hz), 22.8 (d, J C-P ) 44 Hz),
OM000039C