Complexes of Ir3(CO)3(η5-C9H 7)3 with metal fragment electrophiles

Article abstract of DOI:10.1021/om960460u

The reactions of C_3v Ir₃(μ-CO)₃(η⁵-C₉H ₇)₃ (1) with various metal electrophiles yield the cationic tetranuclear clusters [Ir₃{M(PPh₃)}(CO)₃(η⁵-C ₉H₇)₃][PF₆] (2, M = Cu; 3, M = Ag; 5, M = Au), [Ir₃Tl(μ-CO)₃(η⁵-C₉H ₇)₃][PF₆] (4), and [Ir₃(HgR)(CO)₃(η⁵-C₉H ₇)₃][PF₆] (6, R = Ph; 7, R = W(CO)₃(μ-C₅H₅)). Compounds 5-7 are best prepared via compound 4. The structures of compounds 4 and 5 have been determined by X-ray diffraction. The C_3v, symmetry of the parent cluster 1 is maintained in the structure of 4. The molecule consists of a triangle of iridium atoms, each edge of which has a bridging carbonyl oriented out of the plane in the same direction and each vertex of which has an η⁵-indenyl ligand oriented toward the opposite side of the plane. The thallium atom adopts a face-capping mode of coordination on the same side of the triiridium plane as the three indenyl ligands and is encapsulated by the phenylene portions of the indenyl groups. The molecular structure of 5 consists of a AuIr₃ butterfly framework with a hinge angle of 153.63(3)o and the gold atom in a wingtip position. Each CO ligand is bonded in a terminal mode to one iridium center, with one CO ligand 'down' relative to the Ir₃ plane and two CO ligands 'up', flanking the Ir-Ir edge bridged by the Au(PPh₃)+ fragment. The indenyl ligands take up positions opposite those of the CO ligands at each iridium center. The infrared and ¹H NMR spectra of compounds 2, 3, 5, 6, and 7 are all very similar and are fully consistent with the solid-state structure of 5.

Full text of DOI:10.1021/om960460u

Organometallics 1997, 16, 4033-4040
4033
Articles
Com p lexes of Ir 3(CO)3(η5-C9H7)3 w ith Meta l F r a gm en t
Electr op h iles
Matthew C. Comstock, Teresa Prussak-Wieckowska, Scott R. Wilson, and
J ohn R. Shapley*
School of Chemical Sciences, University of Illinois, Urbana, Illinois 61801
Received J une 10, 1996X
The reactions of C3v Ir3(µ-CO)3(η5-C9H7)3 (1) with various metal electrophiles yield the
cationic tetranuclear clusters [Ir3{M(PPh3)}(CO)3(η5-C9H7)3][PF6] (2, M ) Cu; 3, M ) Ag; 5,
M ) Au), [Ir3Tl(µ-CO)3(η5-C9H7)3][PF6] (4), and [Ir3(HgR)(CO)3(η5-C9H7)3][PF6] (6, R ) Ph;
7, R ) W(CO)3(η5-C5H5)). Compounds 5-7 are best prepared via compound 4. The structures
of compounds 4 and 5 have been determined by X-ray diffraction. The C3v symmetry of the
parent cluster 1 is maintained in the structure of 4. The molecule consists of a triangle of
iridium atoms, each edge of which has a bridging carbonyl oriented out of the plane in the
same direction and each vertex of which has an η5-indenyl ligand oriented toward the opposite
side of the plane. The thallium atom adopts a face-capping mode of coordination on the
same side of the triiridium plane as the three indenyl ligands and is encapsulated by the
phenylene portions of the indenyl groups. The molecular structure of 5 consists of a AuIr3
butterfly framework with a hinge angle of 153.63(3)° and the gold atom in a wingtip position.
Each CO ligand is bonded in a terminal mode to one iridium center, with one CO ligand
‘down’ relative to the Ir3 plane and two CO ligands ‘up’, flanking the Ir-Ir edge bridged by
the Au(PPh3)+ fragment. The indenyl ligands take up positions opposite those of the CO
1
ligands at each iridium center. The infrared and H NMR spectra of compounds 2, 3, 5, 6,
and 7 are all very similar and are fully consistent with the solid-state structure of 5.
Sch em e 1
We have previously described the synthesis and
characterization of Ir3(µ-CO)3(η5-C9H7)3 (1) as well as
the related mixed-metal clusters Ir3-xRhx(µ-CO)3(η5-
C9H7)3 (x ) 1, 2).1 The solid-state structure of the
triiridium cluster 1 exhibits nearly C3v symmetry with
three edge-bridging CO ligands oriented toward one face
of the Ir3 triangle and the three η5-indenyl ligands
oriented toward the opposite face. In this form there is
a resemblance of 1 to the well-known triplatinum
clusters Pt3(µ-CO)3(PR3)3, which react readily with a
variety of metal fragment electrophiles.2 We now report
that addition of metal electrophiles to 1 generates the
cationic species [Ir3E(CO)3(η5-C9H7)3][PF6], (2, E ) Cu-
(PPh3); 3, E ) Ag(PPh3); 4, E ) Tl; 5, E ) Au(PPh3); 6,
E ) Hg(Ph); 7, E ) Hg{W(CO)3(η5-C5H5)}) (see Scheme
1). Compounds 5, 6, and 7 are most easily prepared
from the thallium compound, 4.
HgCl{W(CO)3(η5-C5H5)}4 were prepared by literature methods.
Triphenylphosphine (Aldrich), TlPF6 (Strem), AgPF6 (Aldrich),
HgCl(Ph) (Alfa), and AuCl(PPh3) (Aldrich) were used without
further purification. Solvents for preparative use were dried
with the use of standard methods and distilled. The deuter-
ated solvent, (CD3)2CO (Cambridge Isotope Laboratories), was
used as received.
Proton NMR spectra were recorded on a General Electric
QE-300 spectrometer and referenced to residual solvent
resonance (δ 2.04 for acetone-d5). Phosphorus-31 NMR spectra
were recorded at 121.6 MHz on a General Electric GN-300NB
spectrometer and referenced to external 85% H3PO4. Infrared
spectra were recorded on a Perkin-Elmer 1750 FT-IR spec-
Exp er im en ta l Section
Gen er a l P r oced u r es. All manipulations were conducted
under an atmosphere of nitrogen by using standard Schlenk
techniques. The triiridium cluster Ir3(CO)3(η5-C9H7)3 (1) was
prepared from the reaction of Ir(C2H4)2(η5-C9H7) with Ir(CO)2-
(η5-C9H7) as described previously.1 [Cu(NCCH3)4][PF6]3 and
X Abstract published in Advance ACS Abstracts, August 1, 1997.
(1) Comstock, M. C.; Wilson, S. R.; Shapley, J . R. Organometallics
1994, 13, 3805.
trometer. UV-vis spectra were recorded on
Packard HP8452A diode array spectrophotometer. Mass
a Hewlett-
(2) Imhof, D.; Venanzi, L. M. Chem. Soc. Rev. 1994, 185.
(3) Kubas, G. J . Inorg. Synth. 1990, 28, 68.
(4) Mays, M. J .; Robb, J . D. J . Chem. Soc. A 1968, 329.
S0276-7333(96)00460-8 CCC: $14.00 © 1997 American Chemical Society

4034 Organometallics, Vol. 16, No. 19, 1997
Comstock et al.
Ta ble 1. NMR Da ta for Com p ou n d s 2, 3, 5, 6, a n d 7
spectra were recorded on either a VG Quattro spectrometer
(electrospray ionization, ES) or a VG ZAB-SE spectrometer
(fast atom bombardment, FAB) by the staff of the Mass
Spectrometry Laboratory of the School of Chemical Sciences.
Microanalyses were performed by the staff of the Microana-
lytical Laboratory of the School of Chemical Sciences.
1Ha
com-
J 12
H4-H7,
pound Lb
H2
H1,H3 (Hz)
Phc
31P
2
3
L1 5.26 (t) 5.73d
L2 5.87 (m) 6.17 (m)d
L1 5.46 (t) 5.83 (d)
L2 5.89 (m) 6.29 (m)
6.15 (m)
2.7 7.66-6.82 PPh3, 14.97 (s)
2.7 7.72-6.70 PPh3, 18.80 (dd)e
[Ir 3{Cu (P P h 3)}(CO)3(η5-C9H7)3][P F 6] (2). To a red CH2-
Cl2 solution (20 mL) of 1 (30.0 mg, 0.030 mmol) was added
solid [Cu(NCCH3)4][PF6] (11.7 mg, 0.031 mmol), which resulted
in an olive green solution. Peaks in the infrared spectrum at
1980 and 1945 cm-1 were observed. Addition of PPh3 (8.6 mg,
0.033 mmol) with stirring led to a red-brown solution after 15
min. The solvent was removed, and the residue was left under
vacuum for 8 h to remove any excess CH3CN. The residue
was redissolved in CH2Cl2, giving a green solution after
stirring for 20 min. The solvent was removed again, and the
residue was extracted with acetone at 0 °C, filtered to remove
any remaining 1, and then dried under vacuum. Finally, the
residue was triturated with diethyl ether and again dried
under vacuum. Yield: 36 mg (0.024 mmol, 80%). IR (νCO, CH2-
5
L1 5.53 (t) 5.85 (d)
L2 5.81 (m) 6.34 (d)
6.18 (m)
L1 6.02 (t) 6.05 (d)
L2 5.98 (m) 6.57 (m)
6.37 (m)
L1 5.96 (t) 6.04 (d)
L2 5.86 (m) 6.50 (m)
6.27 (m)
2.7 7.80-6.69 PPh3, 51.90 (s)
2.6 7.68-7.07
6
7f
2.7 7.67-7.33
a
The labeling scheme shown below was used for the assign-
b
ments of the indenyl proton resonances. The label L1 refers to
indenyl ligands bisected by a plane of symmetry, and the label L2
refers to indenyl ligands in an asymmetric environment. c The
resonances for H4-H7 and for the phenyl ligands, in those
compounds that contain them, appear as overlapping multiplets.
Cl2): 1981, 1951 cm-1
. Anal. Calcd for C48H36CuF6Ir3O3P2:
C, 39.04; H, 2.46 Found: C, 38.84; H, 2.55. UV-vis (CH2Cl2,
λmax (ꢀ)): 416 (sh, 7980), 608 (4820), 764 (2570) nm. ES-MS
(CH2Cl2): m/z (63Cu, 193Ir) 1333 (Ir3{Cu(PPh3)}(CO)3(C9H7)3+).
The resonances for H1 and H3 are overlapped. e The phosphorus
d
resonance for 3 appeared as two overlapping doublets: 1J (109Ag-
31P) ) 632 Hz, 1J (107Ag-31P) ) 549 Hz. f For C5H5, δ 5.62s.
[Ir 3{Ag(P P h 3)}(CO)3(η5-C9H7)3][P F 6] (3). A solution of
AgPF6 (7.5 mg, 0.030 mmol) in 2 mL of CH3CN was added to
a red CH2Cl2 solution (20 mL) of 1 (30 mg, 0.030 mmol), which
resulted in an olive green solution. Solid PPh3 (7.8 mg, 0.030
mmol) was added, and the solution was stirred for 5 min. The
solvent was removed, and the residue was left under vacuum
for 3 h to remove any excess CH3CN. The residue was
redissolved in CH2Cl2, giving a green solution after stirring
for 20 min. The solvent was removed again, and the residue
was dissolved in acetone, filtered to remove any remaining 1,
and then dried under vacuum. Finally, the residue was
triturated with diethyl ether and again dried under vacuum.
Yield: 31 mg (0.020 mmol, 66%). IR (νCO, CH2Cl2): 1980, 1952
cm-1. Anal. Calcd for C48H36AgF6Ir3O3P2: C, 37.90; H, 2.39.
Found: C, 37.33; H, 2.52. UV-vis (CH2Cl2, λmax (ꢀ)): 404sh
(10 470), 608 (5860), 768 (3070) nm. ES-MS (CH3CN): m/z
nm. ES-MS (CH3CN): m/z (197Au, 193Ir) 1467 (Ir3{Au(PPh3)}-
(CO)3(C9H7)3+).
[Ir 3{HgP h }(CO)3(η5-C9H7)3][P F 6] (6). To a red suspension
of 4 (31 mg, 0.023 mmol) in acetone (10 mL) was added solid
Hg(Ph)Cl (7 mg, 0.023 mmol). The mixture was stirred at
room temperature for 4 h, resulting in a blue-green superna-
tant over a white solid. The solvent was removed under
vacuum, and the residue was extracted with CH2Cl2 (5
10
(
107Ag, 193Ir) 1377 (Ir3{Ag(PPh3)}(CO)3(C9H7)3+); 1114 (Ir3Ag-
mL) through a filter cannula. The solvent was removed under
vacuum. The residue was triturated with diethyl ether and
dried under vacuum. Yield: 28 mg (0.020 mmol, 86%). IR
(νCO, CH2Cl2): 2000, 1968 cm-1. Anal. Calcd for C36H26F6Hg-
Ir3O3P: C, 30.26; H, 1.83 . Found: C, 30.41; H, 2.28. UV-
vis (CH2Cl2, λmax (ꢀ)): 404 (sh, 8260), 484 (sh, 3550), 590 (5660),
726 (2590) nm. ES-MS (CH3CN): m/z (202Hg, 193Ir) 1287 (Ir3-
{HgPh}(CO)3(C9H7)3+).
[Ir 3{HgW(CO)3(η5-C5H5)}(CO)3(η5-C9H7)3][P F 6] (7). To a
red suspension of 4 (30 mg, 0.022 mmol) in acetone (10 mL)
was added an acetone solution of HgCl{W(CO)3(η5-C5H5)} (10
mL, 0.0022 M, 0.022 mmol). The mixture was stirred at room
temperature for 24 h, resulting in a green supernatant over a
white solid. The solvent was removed under vacuum, and the
residue was extracted with CH2Cl2 (5 10 mL) through a filter
cannula. The solvent was removed under vacuum to give
(CO)3(C9H7)3+).
[Ir 3Tl(µ-CO)3(η5-C9H7)3][P F 6] (4). To a red CH2Cl2 solu-
tion (15 mL) of 1 (84 mg, 0.084 mmol) was added solid TlPF6
(27 mg, 0.077 mmol), and the mixture was stirred for 24 h.
The red suspension was dried under vacuum, and the residue
was washed with CH2Cl2 (3 10 mL) to remove any excess 1
and THF (3 10 mL) to remove excess TlPF6. The resulting
red powder was dried under vacuum. Yield: 64 mg (0.047
mmol, 61%). IR (νCO, Nujol) 1820, 1788, 1775 cm-1. Partial
digestion of solid 4 in boiling acetone and cooling to room
temperature provided crystals suitable for X-ray diffraction
and elemental analyses. Anal. Calcd for C30H21F6Ir3O3PTl‚
CH3C(O)CH3: C, 28.04; H, 1.93. Found: C, 27.83; H, 2.01.
FAB-MS (3-NBA): m/z (205Tl, 193Ir) 1213 (Ir3Tl(CO)3(C9H7)3+).
[Ir 3{Au (P P h 3)}(CO)3(η5-C9H7)3][P F 6] (5). To a red sus-
pension of 4 (64 mg, 0.047 mmol) in acetone (50 mL) was added
solid AuCl(PPh3) (24 mg, 0.049 mmol). The mixture was
stirred at room temperature for 24 h, resulting in a green
supernatant over a white solid. The solvent was removed
under vacuum, and the residue was extracted with CH2Cl2 (5
10 mL) through a filter cannula. The solvent was removed
under vacuum, and the solid was washed with benzene (5
10 mL) to remove excess AuCl(PPh3). The residue was
triturated with diethyl ether and dried under vacuum. Yield:
39 mg (0.024 mmol, 52%). X-ray quality crystals were formed
at room temperature by dissolving the green solid in 2-bu-
green microcrystals. Yield: 34 mg (0.020 mmol, 92%). IR (νCO
CH2Cl2): 1997, 1986, 1965, 1916, 1893 cm-1. Anal. Calcd for
38H26F6HgIr3O6PW: C, 27.09; H, 1.56 . Found: C, 26.77; H,
,
C
1.71 . UV-vis (CH2Cl2, λmax (ꢀ)): 424 (sh, 11 100), 490 (sh,
5370), 602 (6840), 740 (3310) nm. FAB-MS (3-NBA): m/z
(
202Hg, 184W, 193Ir) 1543 (Ir3{HgW(CO)3(C5H5)}(CO)3(C9H7)3+).
X-r a y Str u ctu r e Deter m in a tion of 4. The red, transpar-
ent, prismatic crystal was mounted using oil (Paratone-N,
Exxon) to a thin glass fiber. The 001 face of the crystal was
damaged. Data were collected at 198 K on an Siemens
Platform/CCD diffractometer. Crystal and refinement details
are given in Table 2. Systematic conditions suggested the
unambiguous space group P63mc. Scattering factors and
tanone (5 mL) and adding a layer of hexane (5 mL). IR (νCO
,
CH2Cl2): 1986, 1954 cm-1
.
Anal. Calcd for C48H36AuF6-
Ir3O3P2: C, 35.80; H, 2.25. Found: C, 35.67; H, 2.29. UV-
vis (CH2Cl2, λmax (ꢀ)): 410 (sh, 9510), 618 (4530), 770 (3180)

Complexes of Ir3(CO)3(η5-C9H7)3
Organometallics, Vol. 16, No. 19, 1997 4035
Ta ble 2. Cr ysta llogr a p h ic Da ta for 4 a n d 5
compound
4
5
formula
fw
C
30H21F6Ir3O3PTl
C48H36AuF6Ir3O3P2‚C4H8O
1682.38
1355.41
temperature
198(2) K
198(2) K
λ
0.710 73 Å (Mo KR)
P63mc, hexagonal
11.18680(10) Å
11.18680(10) Å
14.8013(2) Å
90
0.710 73 Å (Mo KR)
P21/a, monoclinic
15.985(2) Å
13.438(3) Å
22.960(9) Å
space group, system
a
b
c
R
90
99.86(2)
â
90
120
γ
90
V
1604.14(3) Å3
2
4859(2) Å3
Z
4
Fcalcd
F(000)
cryst size
θ range
2.806 g cm-3
2.30 g cm-3
1212
3128
0.14 0.20 0.50 mm3
2.10-23.25°
0.24 0.18 0.12 mm3
1.76-23.47°
index ranges
Itot (unique, Ri)
abs corr, µ
max/min transmission
refinement method
data/restraints/parameters
goodness of fit (F2)a
R1b, wR2 [I > 2σ(I)]c
R1b, wR2 (all data)c
ext coeff
-9 e h e 12, -12 e k e 12, -16 e l e 13
6076 (854, 0.1265)
integration, 17.526 mm-1
0.1426/0.0097
full-matrix least-squares, F2
854/7/81
-17 e h e 0, -15 e k e 0, -25 e l e 25
7468 (7164, 0.0385)
integration, 11.334 mm-1
0.3360/0.1889
full-matrix least-squares, F2
7164/112/616
1.238
1.006
0.0349, 0.1100
0.0352, 0.1111
0.0099(8)
0.0394, 0.0781
0.0944, 0.1141
0.00005(2)
largest diff peak and hole
+3.887 and -1.185 e Å-3
+1.687 and -1.534 e Å-3
GOF ) [∑[w(Fo - Fc2)2]/(n - p)]1/2; n ) number of reflections, p ) total number of parameters refined. R1 ) ∑ Fo - Fc /∑ Fo
.
a
2
b
c wR2 ) [∑[w(Fo - Fc2)2]/∑[w(Fo2)2]]1/2
.
2
anomalous dispersion terms were taken from standard tables.5
The structure of 4 was solved by direct methods using the
Siemens SHELXTL package of programs;6-8 correct positions
for the metal atoms were deduced from an E-map. One cycle
of isotropic least-squares refinement followed by an un-
weighted difference Fourier synthesis revealed positions for
the remaining non-H atoms. Hydrogen atoms were included
as fixed idealized contributors. H atom U’s were assigned as
1.2Ueq of adjacent C atoms. Non-H atoms were refined with
anisotropic thermal coefficients, except for the fluorine atoms
of the PF6 anion which were disordered between two sites.
These were refined isotropically and the restrained to be
octahedral with the P-F distances at 1.56 ( 0.02 Å. Success-
ful convergence of the full-matrix least-squares refinement of
F2 was indicated by the maximum shift/error for the last cycle.8
The highest peaks in the final difference Fourier map were in
the vicinity of the metal atoms; the final map had no other
significant features. The refined positional parameters are
given in the Supporting Information.
X-r a y Str u ctu r e Deter m in a tion of 5. The opaque, black,
equidimensional crystal was mounted using oil (Paratone-N,
Exxon) to a thin glass fiber. The faces and edges of the crystal
were damaged. Data were measured at 198 K on an Enraf-
Nonius diffractometer. Crystal and refinement details are
given in Table 2. Systematic conditions suggested the unam-
biguous space group P21/a. Periodically monitored standard
intensities showed 0.2% decay; no correction was applied. Step-
scanned intensity data were reduced by profile analysis9 and
corrected for Lorentz-polarization effects and for absorption.10
Scattering factors and anomalous dispersion terms were taken
from standard tables.5 The structure of 5 was solved by direct
methods;7 correct positions for the metal atoms were deduced
from an E-map. One cycle of isotropic least-squares refine-
ment followed by an unweighted difference Fourier synthesis
revealed the positions for the remaining non-H atoms includ-
ing one 2-butanone solvate molecule. Hydrogen atoms were
included as fixed idealized contributors. H atom U’s were
assigned as 1.2Ueq of adjacent C atoms. Non-H atoms were
refined with anisotropic thermal coefficients. Carbon atoms
coordinated to iridium atoms were restrained to be ap-
proximately isotropic (esd ) 0.02). Owing to inaccuracy in the
absorption correction, these C atom displacement parameters
converged to chemically unrealistic values without restraints.
Successful convergence of the full-matrix least-squares refine-
ment of F2 was indicated by the maximum shift/error for the
last cycle.8 The highest peaks in the final difference Fourier
map were in the vicinity of the metal atoms; the final map
had no other significant features. A final analysis of variance
between observed and calculated structure factors showed
dependence on amplitude. The refined positional parameters
are given in the Supporting Information.
Resu lts
Rea ction s of Ir 3(µ-CO)3(η5-C9H7)3 w ith Electr o-
p h iles. The addition of [Cu(NCCH3)4][PF6] to a red
dichloromethane solution of 1 appeared to form an
unstable green [Cu(NCCH3)]+ adduct. Prompt addition
of triphenylphosphine generated [Ir3{Cu(PPh3)}(CO)3-
(η5-C9H7)3][PF6] (2), which was isolated as a green solid
in 80% yield. Similarly, the addition of triphenylphos-
phine to the reaction mixture of 1 and AgPF6 in
dichloromethane formed [Ir3{Ag(PPh3)}(CO)3(η5-C9H7)3]-
[PF6] (3), which was also isolated as a green solid. An
attempt to prepare the analogous [Au(PPh3)]+ adduct
showed that 1 does not react directly with AuCl(PPh3)
in dichloromethane, but in the presence of TlPF6, the
desired compound [Ir3{Au(PPh3)}(CO)3(η5-C9H7)3][PF6]
(5) does form together with a highly insoluble red
precipitate that has been characterized as [Ir3Tl(µ-CO)3-
(5) International Tables for X-ray Crystallography; Wilson, A. J . C.,
Ed.; Kluwer Academic Publishers: Dordrecht, The Netherlands, 1992;
Vol. C, (a) scattering factors, pp 500-502; (b) anomalous dispersion
corrections, pp 219-222.
(6) SHELXTL, Version 5; Siemens Analytical X-Ray Instruments,
Inc.: Madison, WI, 1994.
(7) Sheldrick, G. M. SHELXS-86. Acta Crystallogr. 1990, A46, 467.
(8) Sheldrick, G. M. SHELXL-93; University of Go¨ttingen: Go¨ttin-
gen, Germany, 1993.
(9) Coppins, P.; Blessing, R. H.; Becker, P. J . Appl. Crystallogr. 1972,
7, 488.
(10) Sheldrick, G. M. SHELX-76. Program for crystal structure
determination; University of Cambridge: Cambridge, England, 1976.

4036 Organometallics, Vol. 16, No. 19, 1997
Comstock et al.
(η5-C9H7)3][PF6] (4). Compound 4 was generated di-
rectly from the combination of 1 and TlPF6 in dichlo-
romethane, and it is a useful intermediate for subsequent
reactions in acetone (in which 4 is very slightly soluble)
with AuCl(PPh3), HgCl(Ph), and HgCl{W(CO)3(η5-
C5H5)} to provide [Ir3{Au(PPh3)}(CO)3(η5-C9H7)3][PF6]
(5), [Ir3{HgPh}(CO)3(η5-C9H7)3][PF6] (6), and [Ir3{HgW-
(CO)3(η5-C5H5}(CO)3(η5-C9H7)3][PF6] (7), respectively, in
good yields. These transformations are summarized in
the Scheme 1.
The nature of 4 was especially intriguing, since it
alone among the adducts formed retains the red color
of precursor 1. The FAB mass spectrum of 4 shows the
molecular ion for [Ir3Tl(CO)3(η5-C9H7)3+]. The infrared
spectrum of 4 in Nujol exhibits peaks in the bridging
carbonyl stretching region at 1820 (s, br), 1788 (m), and
1775 (m) cm-1
.
In comparison, the analogous IR
spectrum of 1 displays the same overall peak shapes,
but shifted to lower energy at 1786, 1751, and 1731 cm-1
(see Figure S-1 in the Supporting Information).1 These
data imply the formation of a one-to-one adduct that
maintains the C3v geometry present in the trinuclear
precursor, a fact confirmed by X-ray diffraction (see
below).
F igu r e 1. Proton NMR spectrum in acetone-d6 of 5
(bottom), and proton NMR spectra of 5 including homo-
nuclear decoupling (top 5 spectra).
The infrared spectra of the cationic clusters 2, 3, and
5 in dichloromethane solution show only terminal
carbonyls present with absorption peaks near 1980 and
1950 cm-1. All three clusters exhibit virtually identical
spectra with little deviation in the frequencies of
absorption (see Figure S-2, Supporting Information).
These spectra suggest that 2, 3, and 5 adopt analogous
structures in solution and that the identity of the
coinage metal does not particularly affect the energy of
the CO stretching frequencies. Similarly, the infrared
geometries of both model I and II, which differ by a 180°
rotation of the wingtip Ir(CO)(η5-C9H7) vertex, are
consistent with the NMR spectroscopy. This ambiguity
spectrum for 6 has peaks at 2000 and 1968 cm-1
.
Although the peaks are shifted to higher energy from
those of the coinage metal adducts, the similar peak
shapes suggest an analogous environment for the CO
ligands. The infrared spectrum for 7 also has peaks in
the same region as 6; however, there is overlap of the
Ir-CO bands with W-CO bands from the W(CO)3(η5-
C5H5) moiety.
was resolved in favor of I by an X-ray crystallographic
study of 5 (see below).
The phosphorus NMR spectra of 2, 3, and 5 are clearly
dependent on the identity of the coinage metal. The
chemical shifts of the phosphorus atoms attached to the
coinage metals increase in the order Cu < Ag < Au. The
phosphorus resonance in 3 is split into two doublets of
approximately equal intensity due to spin-spin coupling
with 109Ag and 107Ag (natural abundances of 48.65% and
51.35%, respectively), which confirms coordination of the
phosphine ligand to the coinage metal. The ratio of the
coupling constants 1J (109AgP)/1J (107AgP) ) 632/549 )
1.15, which is approximately the same as the ratio of
the gyromagnetic ratios, γ109Ag/γ107Ag. The chemical
The visible spectra of 2, 3, and 5 in dichloromethane
are all closely comparable with shoulders at 410 (6 nm
and two broad features at 610 (8 and 767 (3 nm (see
Figure S-3, Supporting Information). The visible spec-
trum of 6 has shoulders at 404 and 484 nm and two
broad features at 590 and 726 nm. The visible spectrum
of 7 is closely similar to that of 6, with shoulders at 424
and 490 nm as well as two broad features at 602 and
740 nm.
1
The H NMR spectra of 2, 3, 5, 6, and 7 in acetone
shifts of the phosphorus nuclei in [Rh3{µ3-M(PPh3)}(µ-
are all very similar (see Table 1). The 1H NMR
spectrum of compound 5 and the effects of homonuclear
decoupling are shown as representative examples in
Figure 1. For each compound the spectrum exhibits two
sets of indenyl resonances in a 2:1 ratio. The smaller
set in each case indicates that the indenyl ligand resides
in a symmetric environment. These spectra indicate a
Cs geometry with a mirror plane that is perpendicular
to the Ir3 plane and passes through one iridium atom
(and its indenyl ligand), the midpoint between the two
remaining iridium atoms, and the heterometal. How-
ever, we cannot unambiguously deduce the specific
solution structure of the compounds, since the butterfly
+ 11
CO)3(η5-C5H5)3
]
and for other clusters containing
µ-M(PPh3) units (M ) Cu, Ag, Au)12,13 also increase in
the order Cu < Ag < Au; an appropriate splitting due
to coupling with silver nuclei has been reported as well.
(11) Rybinskaya, M. I.; Kudinov, A. R.; Muratov, D. V.; Gambaryan,
N. P.; Stankevich, I. V.; Chistyakov, A. L. J . Organomet. Chem. 1991,
413, 419.
(12) For examples, see: (a) Evans, J .; Stroud, P. M.; Webster, M.
Organometallics 1989, 8, 1270. (b) Brice, R. A.; Pearse, S. C.; Salter,
I. D.; Henrick, K. J . Chem. Soc., Dalton Trans. 1986, 2181.
(13) (a) Salter, I. D. In Comprehensive Organometallic Chemistry
II; Abel, E. W., Stone, F. G. A.; Wilkinson, G.; Adams, R. D., Eds.;
Pergamon: New York, 1995; Vol. 10, Chapter 5. (b) Salter, I. D. Adv.
Organomet. Chem. 1989, 29, 249.

Complexes of Ir3(CO)3(η5-C9H7)3
Organometallics, Vol. 16, No. 19, 1997 4037
Ta ble 3. Selected Str u ctu r a l Da ta for th e Ca tion 4
Internuclear Distances
Ir1-Ir1′
Ir1-Tl1
Ir1-C11
Ir1-C12
Ir1-C13
2.7118(9)
3.224(2)
2.15(2)
2.232(14)
2.478(14)
Ir1-C1
2.00(2)
1.17 (3)
3.427(13)
3.278(13)
3.131(16)
C1-O1
Tl1-C13
Tl1-C14
Tl1-C15
Bond Angles
Ir1-Tl1-Ir1′
C1-Ir1-Ir1′′
49.74(3)
47.4(5)
Ir1′-Ir1-Tl1
Ir1-C1-Ir1′′
65.128(14)
85.3(9)
Angles between Vectors and Planes
C1,O1 vs Ir1,Ir1′,Ir1′′
53.4
F igu r e 3. ORTEP diagram of the molecular structure of
the cation 5. Only the ipso-carbon atoms of the triphen-
ylphosphine ligand are shown.
tion parameter (∆), the fold angle, and the hinge angle.14
The values of these parameters for 4 are summarized
in Table 5.
The solid state structure of 5 was determined by X-ray
crystallography, and selected results are listed in Table
4. The cation consists of a AuIr3 butterfly with the gold
atom in a wingtip position and a hinge angle of 153.63-
(3)° (see Figure 3). Two of the Ir-Ir distances are
similar, Ir1-Ir2 ) 2.6534(12) and Ir1-Ir3 ) 2.6788-
(10) Å, while the Ir-Ir bond bridged by the gold atom
is longer, Ir2-Ir3 ) 2.7630(9) Å. The bonding Au-Ir
distances are 2.7103(11) and 2.7374(13) Å for Ir2 and
Ir3, respectively (the nonbonding Au-Ir1 distance is
4.506(2) Å). The carbonyl ligands adopt a terminal
mode of coordination, two on one side of the Ir3 plane
and one on the other. The indenyl ligand of the wingtip
Ir atom lies over the same side of the Ir3 plane as the
gold atom, whereas the indenyl ligands on the two hinge
Ir atoms lie over the other side of the Ir3 plane. The
slip distortion parameters, the fold angles, and the hinge
angles for the indenyl ligands attached to Ir1, Ir2, and
Ir3 are given in Table 5.
F igu r e 2. ORTEP diagram of the molecular structure of
the cation 4.
While compounds 5, 6, and 7 are stable in solution,
compounds 2 and 3 are unstable toward loss of the
[M(PPh3)]+ fragment, especially in polar solvents, and
decompose within hours to give back 1. Thus, the
stability of the coinage metal adducts, [Ir3{M(PPh3)}-
(CO)3(η5-C9H7)3], increase in the order M ) Cu < Ag <
Au.
X-r a y Cr ysta l Str u ctu r es of 4 a n d 5. The solid-
state structure of 4 was determined by X-ray crystal-
lography, and selcted results are given in Table 3. The
cation consists of a triangle of iridium atoms, each edge
of which has a bridging carbonyl ligand oriented out of
the plane in the same direction and each vertex of which
has an indenyl ligand oriented toward the opposite side
of the plane (see Figure 2). The thallium atom adopts
a face-capping mode of coordination on the same side
of the Ir3 plane as the indenyl ligands and is surrounded
by the phenylene portions of the indenyl ligands. The
molecule crystallizes in the hexagonal space group
P63mc, and the structure was solved for the unique
atoms Tl1, Ir1, C1, O1, and C11-C15 with the remain-
ing atoms generated by symmetry. The Ir-Ir distance
is 2.7118(9) Å, and the Ir-Tl distance is 3.224(2) Å. The
individual Tl-C distances between the thallium atom
and the carbon atoms of the six-membered ring of the
indenyl ligand range are Tl-C13 ) 3.427(13) Å, Tl-
C14 ) 3.278(13) Å, and Tl-C15 ) 3.131(16) Å. The
structural details of indenyl ligand bonding in (η5-
C9H7)M compounds can be described by the slip distor-
Discu ssion
The reactions of transition metal clusters with coinage
metal fragments is a well-established method of in-
creasing cluster nuclearity.13 The use of Hg2+ reagents
in the synthesis of higher nuclearity clusters has also
been very successful.15 Furthermore, bimetallic re-
agents, such as HgCl{M(CO)3(η5-C5H5)}, lead to clusters
(14) (a) Faller, J . W.; Crabtree, R. H.; Habib, A. Organometallics
1985, 4, 929. (b) Baker, R. T.; Tulip, T. H. Organometallics 1986, 5,
839. (c) Donovan, B. T.; Hughes, R. P.; Trujillo, H. A.; Rheingold, A. L.
Organometallics 1992, 11, 64. (d) Kakkar, A. K.; Taylor, N. J .;
Calabrese, J . C.; Nugent, W. A.; Roe, D. C.; Connaway, E. A.; Marder,
T. B. J . Chem. Soc., Chem. Commun. 1989, 990.
(15) (a) Rosenberg, E.; Hardcastle, K. I. In Comprehensive Organo-
metallic Chemistry II; Abel, E. W., Stone, F. G. A., Wilkinson, G.,
Adams, R. D., Eds.; Pergamon: New York, 1995; Vol. 10, Chapter 6.
(b) Gade, L. H. Angew. Chem., Int. Ed. Engl. 1993, 32, 24.

4038 Organometallics, Vol. 16, No. 19, 1997
Comstock et al.
Ta ble 4. Selected Str u ctu r a l Da ta for th e Ca tion 5
Internuclear Distances
Ir1-Ir2
Ir1-Ir3
Ir2-Ir3
Ir1-C11
Ir1-C12
Ir1-C13
Ir1-C14
Ir1-C19
Ir1-C1
C1-O1
2.6534(12)
2.6788(10)
2.7630(9)
2.27(2)
2.21(2)
2.18(2)
2.303(14)
2.38(2)
1.83(2)
1.14(2)
1.80(2)
Au-Ir1
4.506(2)
2.7103(11)
2.7374(13)
2.19(2)
2.23(2)
2.25(2)
2.38(2)
2.33(2)
1.85(2)
1.15(2)
Au-P1
2.234(4)
Au-Ir2
Au-Ir3
Ir2-C21
Ir2-C22
Ir2-C23
Ir2-C24
Ir2-C29
Ir2-C2
C2-O2
Ir3-C31
Ir3-C32
Ir3-C33
Ir3-C34
Ir3-C39
Ir3-C3
2.240(14)
2.25(2)
2.23(2)
2.31(2)
2.326(14)
1.83(2)
1.14(2)
1.81(2)
C3-O3
P1-C61
P1-C41
P1-C51
1.82(2)
Bond Angles
Ir2-Au-Ir3
Ir1-Ir3-Au
Ir1-Ir3-Ir2
60.95(3)
112.58(3)
58.34(3)
Au-Ir3-Ir2
Ir1-Ir2-Au
Ir2-Ir1-Ir3
59.04(3)
114.28(3)
62.42(3)
Au-Ir2-Ir3
Ir1-Ir2-Ir3
60.01(3)
59.24(3)
Angles between Vectors and Planes
C1,O1 vs Ir1,Ir2,Ir3
C2,O2 vs Ir1,Ir2,Ir3
C3,O3 vs Ir1,Ir2,Ir3
Au,P1 vs Ir1,Ir2,Ir3
83.4
81.1
74.8
25.7
Ta ble 5. Cr ysta llogr a p h ic Ch a r a cter iza tion of
In d en yl Liga n d Distor tion
with an equilibrium constant strongly favoring the C3v
form at 25 °C. Although the reaction pathway in the
formation of the electrophile adducts 2, 3, 5, 6, and 7 is
not clear, it is possible that the electrophilic reagents
attack the Cs isomer preferentially, resulting in the
observed geometries. However, attack upon the C3v
isomer and subsequent isomerization of the Ir3 unit
cannot be ruled out.
∆(slip), fold, hinge,
compound
Ma
Å
deg
10.6 10.1
7.4 8.0
12.3 10.5
deg
ref
1
Ir1
Ir2
Ir3
Ir1
Ir1
Ir2
Ir3
0.28
0.25
0.27
0.25
0.12
0.14
0.08
0.17
1
4
5
6.3
5.1
11.6
10.7
6.0
5.5 this work
5.3 this work
7.3
5.9
7.4 21
The results reported here stand in contrast to those
reported for addition of electrophiles to C3v Rh3(µ-CO)3-
(η5-C5H5)3.11,19 On the basis of ambient infrared and
NMR spectroscopic data, both [Rh3(µ3-MPPh3)(µ-CO)3-
Ir(CO)(η2-dmf)(η5-C9H7)b Ir
a
Values in this column denote the indenyl ligand bonded to M.
η2-dmf ) dimethyl fumarate, trans-MeOC(O)CHdCHC(O)OMe.
b
(η5-C5H5)3+] (M ) Cu, Ag, Au)11 and [Rh3(µ3-H)(µ-CO)3-
+ 19
(η5-C5H5)3
]
were proposed to be C3v-symmetric com-
containing pendant M(CO)3(η5-C5H5) units (M ) Mo,
W)15,16 and enhance the range of metals combined.
Syn th esis of Electr op h ile Ad d u cts. The reactions
of 1 with coinage metal or Hg2+ fragment electrophiles
lead to cationic butterfly clusters 2, 3, 5, 6, and 7,
incorporating the electrophilic metal atoms in wingtip
positions. The solid-state structure of 5 as determined
by X-ray crystallography indicates the Ir3 substructure
has undergone a significant reorganization compared
to the starting material 1.1 Aside from the three
carbonyl ligands now adopting a terminal instead of
bridging mode of coordination, the wingtip Ir(CO)(η5-
C9H7) vertex has been rotated by 180°. Close similari-
ties among the spectroscopic data for these compound-
ssuggest that they all adopt analogous Cs structures in
solution.
In other work,17 we have observed that the reaction
of 1 with HBF4 also leads to a cation with Cs symmetry
and that subsequent deprotonation forms a different
isomer of 1 with Cs symmetry. The geometry of the
latter is presumably similar to the structurally charac-
terized compound Ir3(CO)3(η5-C5H5)3,18 which has ter-
minal carbonyl ligands and two η5 ligands on one side
of the Ir3 plane and one on the other side. The C3v and
Cs isomers of 1 are in equilibrium in dichloromethane,
plexes of the electrophile.
It has been suggested20 that the reason 1 adopts a
structure containing three bridging carbonyl ligands
rather than a structure with all terminal carbonyl
ligands, as observed in Ir3(CO)3(η5-C5H5)3,18 is due to a
relatively large distortion of each indenyl ligand toward
a trihapto (allylic) bonding mode. The distortion of
indenyl ligands from an ideal η5 mode of coordination
in (η5-C9H7)M compounds can be described by the slip
distortion parameter (∆), the fold angle, and the hinge
angle, and compilations of these parameters for a
variety of (η5-C9H7)M and (η3-C9H7)M systems have
been made.14 All of the entries in Table 5 show some
degree of distortion. The degree of distortion in 1 is only
marginally larger than that observed for the cationic
compound 4, although 5 and the mononuclear compound
Ir(CO)(η2-dmf)(η5-C9H7) (dmf ) dimethyl fumarate,
trans-MeOC(O)CHdCHC(O)OMe)21 do show smaller
degrees of distortion. It is thus not truly clear how the
indenyl ligand distortions may affect bridge vs terminal
CO bonding.
The Ir-Tl distance of 3.224(2) Å in 4 is significantly
longer than Pt-Tl distances observed in Pt3 clusters
(16) For example, see: Reina, R.; Rossell, O.; Seco, M.; de Montau-
zon, D.; Zquiak, R. Organometallics 1994, 13, 4300.
(17) Comstock, M. C. Ph.D. Thesis. University of Illinois, Urbana,
IL, 1996.
(18) Shapley, J . R.; Adair, P. C.; Lawson, R. J .; Pierpont, C. G. Inorg.
Chem. 1982, 21, 1701.
(19) Herrmann, W. A.; Plank, J .; Riedel, D.; Ziegler, M. L.; Weiden-
hammer, K.; Guggolz, E.; Balbach, B. J . Am. Chem. Soc. 1981, 103,
63.
(20) Braga, D.; Grepioni, F.; Wadepohl, H.; Gebert, S.; Calhorda,
M. J .; Veiros, L. F. Organometallics 1995, 14, 5350.
(21) Du, Y.; Shapley, J . R. Unpublished results.

Complexes of Ir3(CO)3(η5-C9H7)3
Organometallics, Vol. 16, No. 19, 1997 4039
F igu r e 4. Space-filling diagrams of the structure of 4: (A) from the same perspective as that in Figure 2; (B) along the
3-fold axis.
containing face-bridging thallium atoms.22 For ex-
ample, in [TlPt3(CO)3(PCy3)3][Rh(η-C8H12)Cl2] the thal-
lium atom caps the Pt3 face with an average Pt-Tl
distance of 3.038(1) Å.22a More recently, the reaction
of TlPF6 with a compound containing two tethered Pt3
triangles resulted in a cluster containing Tl bonded in
a sandwich fashion to all six platinum atoms. The Pt-
Tl distances ranged from 2.860(3)-2.992(3) Å.22c Using
the shortest distance in the metal to approximate the
covalent radius of Pt as 1.373 Å,23 the effective covalent
radius of Tl in the TlM3 cluster [TlPt3(CO)3(PCy3)3][Rh-
(η-C8H12)Cl2]22a is 1.665 Å. With the covalent radius of
Ir of 1.357 Å,23 this leads to an expected Tl-Ir bond
distance of 3.022 Å in an analogous TlIr3 cluster.
Compounds with Tl-Ir bonds are rare,24 but comparison
of the Ir-Tl distances of 2.958(1) and 2.979(1) Å in the
A-frame compound [Ir2Tl(CO)2Cl2(µ-dpma)2][NO3]24a of-
fer further evidence for significantly long Tl-Ir interac-
tions in 4.
For compound 4, the average distance between the
thallium atom and the carbon atoms of the six-
membered ring is 3.279 Å, and individual Tl-C dis-
tances range from 3.427(13) Å for Tl-C13 to 3.131(16)
Å for Tl-C15. The interaction of the thallium ion with
the six-carbon rings of the indenyl ligands resembles
crystallographically characterized arene complexes of
thallium.25 For example, the structure of [Tl(1,2,4-
Me3C6H3)2][AlCl4] has average Tl-C distances of 3.265
and 3.351 Å for the two different arene rings.25e There-
fore, the interaction of the thallium with the Ir3 face is
accompanied by close Tl-C distances with the six-
membered rings of the indenyl ligands. The encapsula-
tion of the thallium ion is easily apparent in the space-
filling views of 4 shown in Figure 4. However, despite
this snug fit in the solid-state structure, the thallium
ion is readily able to leave the pocket in acetone solution
for the formation of compounds 5-7.
It appears that the face-bridging configuration for 4
is favored by the significant interaction of the thallium
ion with the π-electron ‘pocket’ created by the three
indenyl ligands and that this interaction weakens the
direct Tl-Ir bonds. It is unlikely, however, that such
heterometallic bonding could be strong enough by itself
to promote formation of the butterfly configuration
favored by the other electrophile adducts, given the
general reluctance of the d10s2 Tl(I) ion to form highly
directional sigma bonds, i.e., the “inert pair effect”.26
In the butterfly configuration adopted by 5, two of the
Ir-Ir distances are similar, Ir1-Ir2 ) 2.6534(12) and
Ir1-Ir3 ) 2.6788(10) Å, while the Ir-Ir bond bridged
by the gold atom is longer, Ir2-Ir3 ) 2.7630(9) Å. The
first two Ir-Ir distances are close to the average
distance in 1 at 2.672 ( 0.006 Å1 while the latter is
significantly longer, consistent with the general obser-
vation for such coinage metal adducts that metal-metal
bond distances increase upon interaction with a bridging
fragment.13 The bonding Au-Ir distances of 2.7103(11)
and 2.7374(13) Å for Ir2 and Ir3, respectively, compare
to the average Ir-Au distance of 2.837 Å in [NMe3(CH2-
Ph)][Ir6(µ-CO)3(CO)12{µ3-Au(PPh3)}], which contains a
face-capping Au(PPh3) unit,27a and the two Ir-Au
distances of 2.788 and 2.731 Å in Ir4(CO)10(µ-PPh2)(µ-
Au(PPh3), which contains an edge-bridging Au(PPh3)
unit.27b The Ir3(CO)3(η5-C9H7)3 substructure in 5 is
analogous to the structure obtained for Ir3(CO)3(η5-
C5H5)3.18 This molecule exhibited two different Ir-Ir
distances, two nearly identical at 2.6693(7) and 2.6697-
(6) Å, and one slightly longer at 2.6876(6) Å.
The transitions in the electronic spectra of green
solutions of 2, 3, 5, 6, and 7 in dichloromethane all
appear at similar energies with broad features near 600
and 750 nm. The visible spectrum of the green, Cs
isomer of 1 also has peaks in the same region.17 In
contrast, the visible spectrum of red solutions of 1 in
dichloromethane shows a strong, low-energy transition
at 528 nm, which has been suggested as a metal-metal
(22) (a) Ezomo, O. J .; Mingos, M. P.; Williams, I. D. J . Chem. Soc.,
Chem. Commun. 1987, 924. (b) Hao, L.; Xiao, J .; Vittal, J . J .;
Puddephatt, R. J .; Manojlovic′-Muir, L.; Muir, K. W.; Torabi, A. A.
Inorg. Chem. 1996, 35, 658. (c) Hao, L.; Vittal, J . J .; Puddephatt, R. J .
Inorg. Chem. 1996, 35, 269.
(23) CRC Handbook of Chemistry and Physics, 71st ed.; Lide, D.
R., Ed.; CRC: Boca Raton, FL, 1990-1991; Section 9, p 2.
(24) (a) Balch, A. L.; Nagle, J . K.; Olmstead, M. M.; Reedy, P. E.,
J r. J . Am. Chem. Soc. 1987, 109, 4123. (b) Balch, A. L.; Neve, F.;
Olmstead, M. M. J . Am. Chem. Soc. 1991, 113, 2995. (c) Van Vliet, P.
I.; Vrieze, K. J . Organomet. Chem. 1977, 139, 337.
(25) (a) Schmidbaur, H. Angew. Chem., Int. Ed. Engl. 1985, 24, 893.
(b) Schmidbaur, H.; Bublak, W.; Riede, J .; Mu¨ller, G. Angew. Chem.,
Int. Ed. Engl. 1985, 24, 414. (c) Noirot, M. D.; Anderson, O. P.; Strauss,
S. H. Inorg. Chem. 1987, 26, 2216. (d) Frank, W.; Korrell, G.; Reiss,
G. J . Z. Anorg. Allg. Chem. 1995, 621, 765. (e) Frank, W.; Korrell, G.;
Reiss, G. J . J . Organomet. Chem. 1996, 506, 293.
(26) Greenwood, N. N.; Earnshaw, A. Chemistry of the Elements;
Pergamon: Oxford, 1984; Chapter 7.
(27) (a) Pergola, R. D.; Demartin, F.; Garlaschelli, L.; Manassero,
M.; Martinengo, S.; Masciocchi, N.; Sansoni, M. Organometallics 1991,
10, 2239. (b) Braga, D.; Grepioni, F.; Livotto, F. S.; Vargas, M. D. J .
Organomet. Chem. 1990, 391, C28.

4040 Organometallics, Vol. 16, No. 19, 1997
Comstock et al.
bonding to metal-metal antibonding transition.1,20 It
appears, therefore, that the gross features in the visible
spectra of the electrophile adducts of 1 reflect the
bonding in the triiridium subunit; discussion of further
details, however, is deferred pending completion of our
comparison of the two isomers of 1.
C
3v geometry of precursor 1, whereas the other adducts
show rearrangement of the Ir3(η5-C9H7)3 moiety to a Cs
geometry.
Ack n ow led gm en t. This research was supported by
the National Science Foundation (Grant No. CHE 94-
14217). Purchase of the Siemens Platform/CCD diffrac-
tometer was supported by the National Science Foun-
dation (Grant No. CHE 95-03145. M.C.C. thanks the
Department of Chemistry for a fellowship funded by the
Lubrizol Corporation. We thank Dr. Udo Brand and
Kwangyeol Lee for help in solving the structure of
compound 4.
Su m m a r y
The reactions of Ir3(µ-CO)3(η5-C9H7)3 (1) with Cu+ or
Ag+ sources followed by addition of PPh3 provided [Ir3-
{Cu(PPh3)}(CO)3(η5-C9H7)3][PF6] (2) and [Ir3{Ag(PPh3)}-
(CO)3(η5-C9H7)3][PF6] (3), respectively, in high yields.
The reaction of 1 with TlPF6 provided the intriguing
complex [Ir3Tl(CO)3(η5-C9H7)3][PF6] (4), which has been
shown to have a thallium ion encapsulated by the six-
membered rings of the indenyl ligands. Compound 4
was found to be a useful precursor in reactions with MCl
reagents to provide the compounds [Ir3E(CO)3(η5-C9H7)3]-
[PF6] (5, E ) Au(PPh3); 6, E ) Hg(Ph); 7, E )
Hg{W(CO)3(η5-C5H5)}). Only adduct 4 maintains the
Su p p or tin g In for m a tion Ava ila ble: Figures S-1, S-2,
and S-3 comparing IR spectra of 1 and 4, IR spectra of 2, 3, 5,
and 6, and UV-visible spectra of 2, 3, 5, and 6 and tables of
atomic coordinates, bond distances and angles, and anisotropic
displacement parameters from the crystallographic studies of
4 and 5 (14 pages). Ordering information is given on any
current masthead page.
OM960460U