Iridabenzenes from iridacyclopentadienes: Unusual C - C bond formation between unsaturated hydrocarbyl ligands

Article abstract of DOI:10.1021/om050529a

Iridabenzenes are produced by an unusual C - C coupling between the α-carbon of the alkynyl ligand and the δ-carbon of the neighboring 1,3-butadienyl ligand upon protonation of the β-carbon of the alkynyl ligand.

Full text of DOI:10.1021/om050529a

Organometallics 2005, 24, 4849-4852
4849
Iridabenzenes from Iridacyclopentadienes: Unusual
C-C Bond Formation between Unsaturated Hydrocarbyl
Ligands
Chong Shik Chin,* Hyungeui Lee, and Min-Sik Eum
Chemistry Department, Sogang University, Seoul, 121-742, Korea
Received June 27, 2005
Summary: Iridabenzenes are produced by an unusual
C-C coupling between the R-carbon of the alkynyl ligand
and the δ-carbon of the neighboring 1,3-butadienyl
ligand upon protonation of the â-carbon of the alkynyl
ligand.
the C-C bond formation between the alkynyl and
neighboring hydrocarbyl ligands.5
Introduction
Metallabenzenes are of interest to many chemists
since these metal-containing aromatic compounds show
some interesting reactivity compared with that of
organic aromatics.1 Metal-mediated carbon-carbon bond
forming reactions between alkynes have been utilized
to prepare metallabenzenes and related unsaturated
six-membered metallacycles (metallabenzynes and iso-
metallabenzenes).1,2 We recently reported the synthesis
of iridabenzenes from reactions of iridacyclopentadienes
with alkynes (eq 1).3 The C-C bond formation between
the hydrocarbyl ligands is initiated by protonation of
the â-carbon of the alkynyl ligand of 2, and further
protonation of the vinyl carbon in the presence of a base
(CH3CN) yields the stable iridabenzenes 3. It may also
be possible to prepare iridabenzenes via the intra-
molecular rearrangement of pent-2,4-dien-1-yl com-
plexes, M-C(dCHR)-CHdCH-CHdCH2, since a pent-
1,3-dien-1-yl-iridium has been suggested as the tran-
sient species that undergoes C-H activation to produce
iridabenzene.4 One can expect pent-2,4-dien-1-yl com-
plexes, M-C(dCHR)-CHdCH-CHdCH2, as the prod-
ucts of the reaction of cis-(alkynyl)(but-1,3-dien-1-yl)
complexes, M(-CtCR)(-CHdCH-CHdCH2), with pro-
ton through the C-C coupling reaction between the two
unsaturated hydrocarbyl ligands since the â-carbon of
the alkynyl ligand (M-CtCR) is well-known to be so
nucleophilic that it readily reacts with proton to initiate
We now wish to report another synthetic synthesis
of iridabenzenes via an unusual C-C bond forming
reaction between the R-carbon of the alkynyl and the
δ-carbon of the but-1,3-dien-1-yl ligands of cis-(alkynyl)-
(but-1,3-dien-1-yl)iridium complexes.
Results and Discussion
Newly prepared (η2-acetato)iridacyclopentadiene 4
reacts with alkynes (RCtCH) to produce new cis-
(alkynyl)(but-1,3-dien-1-yl)iridium 5, which is readily
protonated to give iridabenzenes 6 in high yields (eq 2).
Iridabenzenes 6 are also obtained from ligand substitu-
tion reactions of cis-bis(acetonitrile)iridabenzenes 33
with CH3CO2Na. It is likely that proton attacks the
â-carbon of the alkynyl group of 5 to cause the C-C
bond formation between the hydrocarbyl (alkynyl and
but-1,3-dien-1yl) ligands to give iridabenzenes 6 (see
below for the reaction mechanism). It is somewhat
(5) (a) Chin, C. S.; Lee, H.; Noh, S.; Park, H.; Kim, M. Organo-
metallics 2003, 22, 2119. (b) Chin, C. S.; Kim, M.; Lee, H. Organo-
metallics 2002, 21, 1679. (c) Chin, C. S.; Cho, H.; Won, G.; Oh, M.; Ok,
K. M. Organometallics 1999, 18, 4810. (d) Chin, C. S.; Lee, H.; Park,
H.; Kim, M. Organometallics 2002, 21, 3889. (e) Chin, C. S.; Kim, M.;
Lee, H.; Noh, S.; Ok, K. M. Organometallics 2002, 21, 4785. (f) Chin,
C. S.; Won, G.; Chong, D.; Kim, M.; Lee, H. Acc. Chem. Res. 2002, 35,
218. (g) Chin, C. S.; Kim, M.; Won, G.; Jung, H.; Lee, H. Dalton Trans.
2003, 2325. (h) Chin, C. S.; Maeng, W.; Chong, D.; Won, G.; Lee, B.;
Park, Y. J.; Shin, J. M. Organometallics 1999, 18, 2210. (i) Werner,
H.; Ilg, K.; Weberndo¨rfer, B. Organometallics 2000, 19, 3145. (j)
Jime´nez-Tenorio, M. A.; Jime´nez-Tenorio, M.; Puerta, M. C.; Valerga,
P. Organometallics 2000, 19, 1333. (k) Yang, J.-Y.; Huang, S.-L.; Lin,
Y.-C.; Liu, Y.-H.; Wang, Y. Organometallics 2000, 19, 269. (l) Bohana,
C.; Buil, M. L.; Esteruelas, M. A.; On˜ate, E.; Valero, C. Organometallics
1999, 18, 5176. (m) Bianchini, C.; Mantovani, N.; Marchi, A.; Marvelli,
L.; Masi, D.; Peruzzini, M.; Rossi, R.; Romerosa, A. Organometallics
1999, 18, 4501. (n) Slugovc, C.; Mereiter, K.; Schmid, R.; Kirchner, K.
J. Am. Chem. Soc. 1998, 120, 6175. (o) Huang, D.; Oliva´n, M.; Huffman,
J. C.; Eisenstein, O.; Caulton, K. G. Organometallics 1998, 17, 4700.
(p) O’Connor, J. M.; Hiibner, K.; Merwin, R.; Gantzel, P. K.; Fong, B.
S. J. Am. Chem. Soc. 1997, 119, 3631. (q) Ipaktschi, J.; Mirzaei, F.;
Demuth-Eberle, G. J.; Beck, J.; Serafin, M. Organometallics 1997, 16,
3965. (r) Yang, S.-M.; Chan, M. C.-W.; Cheung, K.-K.; Che, C.-M.; Peng,
S.-M. Organometallics 1997, 16, 2819. (s) Bianchini, C.; Innocenti, P.;
Peruzzini, M.; Romerosa, A.; Zanobini, F. Organometallics 1996, 15,
272.
* To whom correspondence should be addressed. E-mail: cschin@
sogang.ac.kr.
(1) (a) Lautens, M.; Klute, W.; Tam, W. Chem. Rev. 1996, 96, 49.
(b) Saito, S.; Yamamoto, Y. Chem. Rev. 2000, 100, 2901. (c) Burrows,
A. D.; Green, M.; Jeffery, J. C.; Lynam, J. M.; Mahon, M. F. Angew.
Chem., Int. Ed. 1999, 38, 3043.
(2) (a) Barrio, P.; Esteruelas, M. A.; On˜ate, E. J. Am. Chem. Soc.
2004, 126, 1946. (b) Xia, H.; He, G.; Zhang, H.; Wen, T. B.; Sung, H.
H. Y.; Williams, I. D.; Jia, G. J. Am. Chem. Soc. 2004, 126, 6862. (c)
Paneque, M.; Posadas, C. M.; Poveda, M. L.; Rendo´n, N.; Salazar, V.;
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T. B.; Zhou, Z. Y.; Jia, G. Angew. Chem., Int. Ed. 2001, 40, 1951. (e)
Wen, T. B.; Ng, S. M.; Houg, W. Y.; Zhou, Z. Y.; Lo, M. F.; Shek, L.-Y.;
Williams, I. D.; Lin, Z.; Jia, G. J. Am. Chem. Soc. 2003, 125, 884.
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10.1021/om050529a CCC: $30.25 © 2005 American Chemical Society
Publication on Web 08/30/2005

4850 Organometallics, Vol. 24, No. 20, 2005
Notes
unusual not to observe the conjugate trienes (RCHd
CH-CHdCH-CHdCH2) from the reactions of 5 with
H+ (eq 2) since it is well-established that the reactions
of alkynyl complexes with H+ cause the C-C coupling
reaction between the two R-carbons of the alkynyl and
a neighboring unsaturated hydrocarbyl ligand to give
conjugated polyenes and polyenynes.5 Complexes 5 do
not undergo the reductive elimination of the hydrocarbyl
ligands to give conjugated dienynes (R-CtC-CHd
CH-CHdCH2) even at 60 °C in CHCl3 in the absence
of H+. 1,3-Butadiene is liberated from reactions of 5 with
excess RCtCH to give cis-bis(alkynyl)iridium (Ir(η2-
O2CH3)(-CtCR)2(PPh3)2) and with H+ in the presence
of RCtCH to give unknown iridium complex(es).6
between the R-carbons of the alkynyl and but-1,3-dien-
1-yl ligands (pathway A), but support pathway B as the
main route in eq 4. The iridacyclohexadiene I-d(C4, C4)
may then be aromatized through the well-known 1,3-
shift reaction of hydrogen to produce iridabenzene 6a-
d(C4, C6)).
The sum of deuterium found at the two carbons
C4 and C6 of 6a-d(C4, C6) is somewhat less than 1.0
(ca. 0.7: ca. 0.4 at C4 and ca. 0.3 at C6) according to
To look into the reaction pathways of this C-C
coupling in detail as well as the following intramolecular
hydrogen transfer steps to give the final product irida-
benzene, two different deuterium-labeling experiments
have been carried out.
the integration of signals at δ 6.05 (Ir-CHdCH-CHd
C(4)H-C(CH2Ph) and 4.66 (Ir-CHdCH-CHdCH-C-
The reaction of 5a with D+ produces the iridabenzene
6a-d(C6), containing deuterium only at the sixth carbon
from the metal, the methylene carbon (-C(6)HDPh) (eq
3), which confirms the C-C coupling reaction being
initiated by the attack of D+ on the â-carbon of the
alkynyl ligand of 5a and the deuterium staying at the
same carbon during the following intramolecular re-
arrangements to give iridabenzene 6a-d(C6).
1
(C(6)H2Ph) ppm in the H NMR spectrum of 6a-d(C4,
C6) (see Supporting Information). It may be conceivable
that some of the deuterium is transferred during the
1,3-shift reaction of deuterium (or hydrogen) between
the intermediate I-d(C4, C4) and the iridabenzene 6a-
d(C4, C6), possibly to the solvent CHCl3 through the
H/D exchange mediated by the conjugate anion OTf-
(-OSO2CF3) present in the reaction mixture.
New iridium compounds, 4, 5, 6, and (Ir(η2-O2CCH3)-
(-CtCR)2 (PPh3)2) prepared in this study have been
1
unambiguously characterized by detailed spectral H,
1
13C, and 31P{1H} NMR, H,13C-HETCOR, IR (see Sup-
porting Information), and elemental analysis data.
Straightforward assignments were possible for the
signals in the NMR spectra of new compounds by
comparing with those for related compounds previously
reported.3,5,7
Two different reaction pathways (A and B in eq 4)
may be considered for the C-C bond formation between
the hydrocarbyl ligands of 5 to produce iridabenzene 6.
Pathway A includes the well-established C-C coupling
between the R-carbons of the two neighboring hydro-
carbyl ligands initiated by the protonation of the
â-carbon of the alkynyl ligand, whereas pathway B
involves the somewhat unusual C-C bond formation
between the R-carbon of the alkynyl ligand and the
δ-carbon of the but-1,3-dien-1-yl ligand.
1H NMR spectra of the isotopomers 5a-d(C4),
6a-d(C6), and 6a-d(C4, C6) clearly show decreases only
in the integration of the corresponding hydrogens,
i.e., at δ 4.82 for Ir-CHdCH-CHdCHcisHtrans and δ
4.68 for Ir-CHdCH-CHdCHcisHtrans of 5a; at δ 4.66
for [IrdCH-CHdCH-CHdC(CH2Ph) of 6a; at δ 6. 05
and 4.66 for the two hydrogens IrdCH-CHdCH-
The reaction of 4 with PhCtCD gives the isotopomer
5a-d(C4), having deuterium only at the δ-carbon (the
fourth carbon from the metal; 0.5 deuterium at the cis-
and trans-position, respectively) of the but-1,3-dien-1-
CHdC(CH2Ph) of 6a, respectively (see Supporting In-
formation).
1
yl ligand according to the H NMR spectral data (see
eq 4 and Supporting Information). The iridabenzene 6a-
d(C4, C6), obtained from the reaction of 5a-d(C4) with
H+, contains deuterium at the two carbons C4 and C6
(eq 4) and does not seem to have deuterium on the
R-carbon (C1) at all. These results unambiguously
exclude the possibility of the C-C bond formation
In summary, iridabenzenes [Ir(CHCHCHCHC(CH2R)-
L4)]+ (L4 ) (η2-O2CCH3)(PPh3)2; R ) Ph, p-C6H4CH3) are
prepared from the reactions of cis-(alkynyl)(but-1,3-dien-
1-yl)iridium [Ir(-CtCR)(-CHdCHCHdCH2)L4]+ with
(7) (a) Ara, I.; Berenguer, J. R.; Eguiza´bal, E.; Fornie´s, J.; Lalinde,
E.; Mart´ınez, F. Organometallics 1999, 18, 4344. (b) Ara, I.; Berenguer,
J. R.; Eguiza´bal, E.; Fornie´s, J.; Lalinde, E.; Mart´ın, A.; Mart´ınez, F.
Organometallics 1998, 17, 4578. (c) Ferna´ndez, F. J.; Alfonso, M.;
Schmalle, H. W.; Berke, H. Organometallics 2001, 20, 3122.
(6) The reactions of 5 with H+ in the presence of RCtCH (3 equiv)
produce a mixture of iridabenzene 6 and unknown iridium complex-
(es), and a small amount of 1,3-butadiene.

Notes
Organometallics, Vol. 24, No. 20, 2005 4851
H+. The plausible reaction mechanism involves (i)
proton attack on the â-carbon of the alkynyl ligand (Ir-
CtCPh) to form the vinylidene complex [Ir(dCdCHPh)-
(-CHdCH-CHdCH2)L4]+ and (ii) an unusual C-C
bond formation between the R-carbon of the vinyl-
idene ligand (Ir+dCdCHPh) and the δ-carbon of the
cis-but-1,3-dien-1-yl ligand (Ir-CHdCH-CHdCH2) to
CHCHdCH2), 130.99, 127.14, and 123.92 (s, CH carbons of
C6H5), 130.19 (s, Ir-CHdCHCHdCH2), 129.52 (s, Cipso carbons
of C6H5), 116.08 (br s, Ir-CHdCHCHdCH2), 111.14 (s, Ir-
CHdCHCHdCH2), 104.78 (s, Ph-CtC-Ir), 70.97 (t, J(C-P)
) 14 Hz, Ph-CtC-Ir), 23.58 (s, Ir-η2-O2CCH3). HETCOR (1H
(500 MHz) f 13C (126 MHz)): δ 7.44 f 116.08; ca. 6.9 f
138.15; 5.60 f 130.19; 4.82 and 4.68 f 111.14; 0.65 f 23.58.
31P{1H} NMR (81 MHz, CDCl3): δ 10.17 (s, PPh3). IR (KBr,
cm-1): 2113.4 (s, νCtC). Anal. Calcd for Ir1P2O2C50H43: C, 64.57;
H, 4.66. Found: C, 64.55; H, 4.68.
give the hexadienyl complex ([IrdCHCHdCHCH2-C-
(dCHPh)L4]+), which undergoes the well-known hydro-
gen 1,3-shift reaction to produce the iridabenzene
[IrCHCHCHCHC(CH2Ph)L4]+.
Experimental Section
General Procedures. A standard vacuum system and
Schlenk type glassware were used in most of the experiments
in handling metal complexes, although most of the compounds
are stable enough to be handled in air. PhCtCD, HOTf, and
Ir(-CHdCHCHdCH2)(-CtC-p-C6H4CH3)(η2-O2CCH3)-
(PPh3)2, 5b. 1H NMR (CDCl3, 500 MHz): δ 7.3-7.6 (m,
P(C6H5)3 and Ir-CHdCHCHdCH2, 31H), 6.90 (dt, J(H-H) )
16.5 Hz, J(H-H) ) 10.3 Hz, Ir-CHdCHCHdCH2, 1H), 6.27-
6.79 (AB system, p-C6H4CH3, 4H), 5.59 (t, J(H-H) ) 10.3 Hz,
Ir-CHdCHCHdCH2, 1H), 4.82 (d, J(H-H) ) 10.3 Hz, Ir-
CHdCHCHdCHcisHtrans, 1H), 4.68 (d, J(H-H) ) 16.5 Hz, Ir-
CHdCHCHdCHcisHtrans, 1H), 2.22 (s, p-C6H4CH3, 3H), 0.66 (s,
Ir-η2-O2CCH3, 3H). 13C NMR (CDCl3, 126 MHz): δ 185.93 (s,
Ir-η2-O2CCH3), 138.22 (s, Ir-CHdCHCHdCH2), 129.94 (s, Ir-
CHdCHCHdCH2), 130.80 and 127.90 (s, CH carbons of
p-C6H4CH3), 127.83 (s, Cipso carbons of p-C6H4CH3), 116.18 (br
s, Ir-CHdCHCHdCH2), 110.05 (s, Ir-CHdCHCHdCH2),
104.50 (s, p-tolyl-CtC-Ir), 68.95 (br s, p-tolyl-CtC-Ir), 23.57
(s, Ir-η2-O2CCH3), 21.08 (s, p-C6H4CH3). HETCOR (1H (500
MHz) f 13C (126 MHz)): δ ca. 7.4 f 116.18; 6.90 f 138.22;
5.59 f 129.94; 4.82 and 4.68 f 110.05; 2.22 f 21.08; 0.66 f
23.57. 1P{1H} NMR (CDCl3, 81 MHz): δ 10.11 (s, PPh3). IR
(KBr, cm-1): 2117 (νCtC). Anal. Calcd for Ir1P2O2C51H45: C,
64.88; H, 4.80. Found: C, 64.93; H, 4.81.
DOTf were purchased from Aldrich. [Ir(CHdCHCHdCH)-
(NCCH3)(CO) (PPh3)2]OTf was prepared by literature methods.4e
NMR spectra were measured using a Varian 200 or 500 MHz
spectrometer for 1H, 125.7 MHz for 13C, and 81 or 121.3 MHz
for 31P. Infrared spectra were obtained on a Nicolet 205.
Elemental analyses were performed at the Organic Chemistry
Research Center, Sogang University, using a Carlo Erba EA
1108.
Synthesis of Ir(CHdCHCHdCH)(η2-O2CCH3)(PPh3)2, 4.
To a solution of [Ir(CHdCHCHdCH) (NCCH3)(CO)(PPh3)2]OTf
(0.098 g, 0.1 mmol) in CHCl3 (10 mL) were added Me3NO
(0.019 g, 0.25 mmol) and CH3CN (0.012 g, 0.3 mmol), and the
reaction mixture was stirred at 25 °C under N2 for 30 min
before the pale yellow solution turned light brown. Excess
Me3NO and NMe3 were removed by extraction with H2O (2 ×
10 mL). A light brown solution of CHCl3 was stirred in the
presence of CH3CO2Na (0.15 mmol) at 25 °C for 3 h before
MeOH (30 mL) was added to precipitate beige microcrystals,
which were collected by filtration, washed with n-pentane (3
× 10 mL), and dried under vacuum. The yield was 0.097 g
Synthesis of [Ir(CHCHCHCHC(CH2Ph))(η2-O2CCH3)-
(PPh3)2](OTf), 6a. Both 6a and 6b were synthesized in the
same manner as described below for 6a. HOTf (11 µL, 0.12
mmol) was added to a solution of 5a (0.093 g, 0.1 mmol) in
CHCl3 (15 mL) at 25 °C, and the reaction mixture was stirred
for 5 min. Excess HOTf was removed by extraction with H2O.
Addition of n-pentane (10 mL) to the CHCl3 solution resulted
in beige microcrystals, which were collected by filtration,
washed with n-pentane (3 × 10 mL), and dried under vacuum.
The yield was 0.08 g and 79% based on 6a. 1H NMR (500 MHz,
CDCl3): δ 13.13 (d, J(H-H) ) 7.5 Hz, H1), 7.2-7.9 (m,
P(C6H5)3, H2 and H3, 32H), 6.28 (d, J(H-H) ) 7 Hz, C6H5,
2H), 6.02 (d, J(H-H) ) 8.5 Hz, H4, 1H), 4.63 (s, H6, 2H), 0.486
(s, Ir-η2O2CCH3, 3H). 13C NMR (126 MHz, CDCl3): δ 241.0
(br s, C5), 208.63 (br, C1), 187.4 (s, Ir-η2O2CCH3), 162.36 and
129.36 (both s, C2 and C3), 27.27 (s, C4), 56.65 (s, C6), 23.30
(s, Ir-η2O2CCH3), 134.5, 132.5, 128.9, and 124.7 (P(C6H5)3),
120.98 (q, J(C-F) ) 320.79 Hz, CF3SO3). HETCOR (1H (500
MHz) f 13C (126 MHz)): δ 13.13 f 208.63; ca. 7.6 f 162.36;
ca. 7.3 f 129.36; 6.02 f 127.27; 4.63 f 56.65; 0.486 f 23.30.
31P{1H} NMR (CDCl3; 81 MHz): δ 10.76 (s, PPh3). IR (KBr,
1
and 98% based on 4. H NMR (500 MHz, CDCl3): δ 7.3-7.5
(m, P(C6H5)3, 30H), 6.86 (m, Ir-CHdCHCHdCH, 2H), 5.63
(m, Ir-CHdCHCHdCH, 2H), 0.48 (s, Ir-η2-O2CCH3, 3H). 13
C
NMR (126 MHz, CDCl3): δ 183.5 (s, Ir-η2-O2CCH3), 143.6 (s,
Ir-CHdCHCHdCH), 132.9 (t, J(C-P) ) 8.0 Hz, Ir-CHd
CHCHdCH), 24.1 (s, Ir-η2-O2CCH3), 135.05, 129.81, 129.79,
and 127.48 (P(C6H5)3). HETCOR (1H (500 MHz) f 13C (126
MHz)): δ 0.48 f 24.1; 5.63 f 143.6; 6.86 f 132.9. 31P{1H}
NMR (81 MHz, CDCl3): δ 13.36 (s, PPh3). Anal. Calcd for
Ir1P2O2C42H37: C, 60.93; H, 4.50. Found: C, 60.90; H, 4.49.
Synthesis
of
Ir(-CHdCHCHdCH2)(CtCPh)(η2-
O2CCH3)(PPh3)2, 5a. Both 5a and 5b were synthesized in the
same manner as described below for 5a. A CHCl3 (10 mL)
solution of 4 (0.084 g, 0.1 mmol) and C6H5CtCH (0.010 g, 0.10
mmol) was stirred at 25 °C for 10 min before n-pentane (20
mL) was added to precipitate light yellow microcrystals, which
were collected by filtration, washed with n-pentane (3 × 10
mL), and dried under vacuum. The yield was 0.096 g and 98%
based on 5a. 1H NMR (500 MHz, CDCl3): δ 7.3-7.6 (m,
P(C6H5)3, 30H), 7.44 (d, J(H-H) ) 10 Hz, Ir-CHdCHCHd
CH2, 1H), 6.86-6.97 (m, metha- and para-protons of C6H5 and
Ir-CHdCHCHdCH2, 4H), 6.36 (d, J(H-H) ) 7 Hz, ortho-
protons of C6H5, 2H), 5.60 (t, J(H-H) ) 10 Hz, Ir-CHd
CHCHdCH2, 1H), 4.82 (d, J(H-H) ) 10 Hz, Ir-CHdCHCHd
CHcisHtrans, 1H), 4.68 (d, J(H-H) ) 17 Hz, Ir-CHdCHCHd
CHcisHtrans, 1H), 0.65 (s, Ir-η2-O2CCH3, 3H). 13C NMR (126
MHz, CDCl3): δ 185.98 (s, Ir-η2-O2CCH3), 138.15 (s, Ir-CHd
cm-1): 1263.6, 1155.6, and 1031.5 (s, νOTf ). Anal. Calcd for
-
Ir1P2O5S1F3C51H44: C, 56.71; H, 4.11; S, 2.97. Found: C, 56.75;
H, 3.97; S, 2.89.
[Ir(CHCHCHCHC(CH2-p-C6H4CH3))(η2-O2CCH3)(PPh3)2]-
1
(OTf), 6b. H NMR (CDCl3, 500 MHz): δ 13.12 (d, J(HH) )
7.0 Hz, H1), 7.1-7.7 (m, P(C6H5)3, H2 and H3, 32H), 6.15-
7.00 (AB type, p-C6H4CH3, 4H), 6.04 (d, J(HH) ) 8.5 Hz, H4,
1H), 4.62 (s, H6, 2H), 2.31 (s, p-C6H4CH3, 3H), 0.50 (s,
Ir-η2O2CCH3, 3H). 13C NMR (CDCl3, 125.7 MHz): δ 241.96 (br
s, C5), 208.3 (br, C1), 187.47 (s, Ir-η2O2CCH3), 162.40 and
130.76 (both s, C2 and C3), 129.74 and 129.53 (both s, CH
carbons of C6H4CH3), 127.43 (s, C4), 56.48 (s, C6), 23.44 (s,
Ir-η2O2CCH3), 21.32 (s, C6H4CH3), 134.6, 132.6, 129.0 and

4852 Organometallics, Vol. 24, No. 20, 2005
Notes
124.8 (P(C6H5)3), 121.2 (q, J(CF) ) 321.4 Hz, CF3SO3).
HETCOR (1H (500 MHz) f 13C (126 MHz)): δ 13.12 f 208.3;
ca. 7.6 f 162.40; ca. 7.3 f 130.76; 6.04 f 127.43; 4.62 f 56.48;
2.31 f 21.32; 0.50 f 23.44. 31P NMR (CDCl3, 81 MHz): δ 10.73
6.84-6.93 (m, meta- and para-protons of CtCC6H5, 6H), 6.14
(d, ortho-protons of CtCC6H5, 4H), 0.62 (s, Ir-η2-O2CCH3, 3H).
13C NMR (126 MHz; CDCl3): δ 188.1 (s, Ir-η2-O2CCH3), 131.3,
126.9, and 124.2 (s, CH carbons of Ir-CtCC6H5), 128.8 (s, ipso-
carbons of Ir-CtCC6H5), 103.9 (s, Ir-CtC), 60.8 (t, J(C-P)
) 13.0 Hz, Ir-CtC), 23.3 (s, Ir-η2-O2CCH3), 135.2, 130.2,
130.0, and 127.9 (P(C6H5)3). HETCOR (1H (500 MHz) f 13C
(126 MHz)): δ 6.91 f 126.9; 6.86 f 124.2; 6.14 f 131.3; 0.62
f 23.3. 31P{1H} NMR (81 MHz; CDCl3): δ 10.43 (s, PPh3). IR
(KBr, cm-1): 2118.4 (s, CtC). Anal. Calcd for Ir1P2O2C54H43:
C, 66.31; H, 4.43. Found: C, 66.25; H, 4.38.
(s, PPh3). IR (KBr, cm-1): 1262, 1155, and 1032 (νOTf ). Anal.
-
Calcd for Ir1P2O5S1F3C52H46: C, 57.08; H, 4.24; S, 2.93.
Found: C, 56.97; H, 4.01; S, 2.83.
Synthesis of Isotopomers Ir(-CHdCHCHdCHD)(Ct
CPh)(η2-O2CCH3)(PPh3)2, 5a-d(C4), [IrdCH-CHdCH-
CHdC(CHDPh)(η2-O2CCH3)(PPh3)2]+, 6a-d(C6), and
[IrdCH-CHdCH-CH1-yDydC(CH2-xDxPh)(η2-O2CCH3)-
(PPh3)2]+, 6a-d(C4, C6) (0.5 < x + y < 1). These isotopomers
were prepared in the same manner as described above for 5a
and 6a except that deuterium-containing reagents, DOTf and
PhCtCD, were used.
Acknowledgment. The authors wish to thank the
Korea Research Foundation (KRF) for their financial
support of this study through the Basic Science Re-
search Institute program (Grant No. KRF-2004-015-
C00251).
Synthesis of Ir (η2-O2CCH3)(-CtCC6H5)2(PPh3)2. A
CHCl3 (10 mL) solution of 5a (0.10 g, 0.093 mmol) and C6H5Ct
CH (0.010 g, 0.10 mmol) was stirred at 25 °C for 10 min before
n-pentane (20 mL) was added to precipitate light yellow
microcrystals, which were collected by filtration, washed with
n-pentane (3 × 10 mL), and dried under vacuum. The yield
was 0.11 g and 98% based on Ir(-CtCPh)2(η2-O2CCH3)(PPh3)2.
1H NMR (500 MHz; CDCl3): δ 7.18-7.77 (m, P(C6H5)3, 30H),
Supporting Information Available: 1H and 13C NMR
spectra of complexes 4, 5a, 5a-d(C4), 6a, 6a-d(C6), 6a-d(C4,
C6), and Ir(-CtCC6H5)2(η2-O2CCH3)(PPh3)2. This material is
available free of charge via the Internet at http://pubs.acs.org.
OM050529A