Formation of an iodide-bridged diruthenium complex from [(n 5-Ph4C4COH)(CO)2RuI] and [(Ph 4C4CO)(CO)2Ru]2: An efficient catalyst for alcohol oxidation with Ag2</s

Article abstract of DOI:10.1021/om9003434

Summary: Iodide-bridged diruthenium complexes, [(η⁵-2, 5R₂-3,4-Ph₂C₄COH) (CO)₂Ru-(μ-I)- Ru(CO)₂(η⁴-2,5-R₂3,4-Ph₂C ₄CO)] (6a, R = Ph; 6b, R = Me),

Full text of DOI:10.1021/om9003434

4624 Organometallics 2009, 28, 4624–4627
DOI: 10.1021/om9003434
Formation of an Iodide-Bridged Diruthenium Complex from [(η5-
Ph4C4COH)(CO)2RuI] and [(Ph4C4CO)(CO)2Ru]2: An Efficient
Catalyst for Alcohol Oxidation with Ag2O
Youngshil Do,† Soo-Byung Ko,† In-Chul Hwang,† Kyung-Eun Lee,‡ Soon W. Lee,‡ and
Jaiwook Park*,†
†Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang Gyungbuk
790-784, Republic of Korea, and ‡Department of Chemistry, Sungkyunkwan University, Natural Science
Campus, Suwon 440-746, Republic of Korea
Received May 1, 2009
Summary: Iodide-bridged diruthenium complexes, [(η5-2,5-
R2-3,4-Ph2C4COH)(CO)2Ru-(μ-I)-Ru(CO)2(η4-2,5-R2-
3,4-Ph2C4CO)] (6a, R=Ph; 6b, R=Me), were formed from
the reaction of (η5-2,5-R2-3,4-Ph2C4COH)(CO)2RuI (2c, R=
Ph; 2d, R=Me) with [(2,5-R2-3,4-Ph2C4CO)(CO)2Ru]2 (7a,
R=Ph; 7b, R=Me). The complexes exhibited a high catalytic
activity for the oxidation of alcohols with silver oxide at room
temperature.
heating was required to activate 1 dormant under ambient
conditions, and it was proposed that heating cleaves 1 into
ruthenium hydride complex 2a and 16-electron ruthenium
cyclopentadienone species 3 (Scheme 1).9 Casey and co-
workers observed the hydrogen-transfer reactions of ketones
and imines when 2a was employed.9,10 A closely related
monoruthenium complex, (η5-Ph4C4COH)(CO)2RuCl (2b),
was shown to exhibit a catalytic activity for the oxidation of
alcohols with chloroform as an oxidant.11 However, this
oxidation also required the heating of 2b at 90 °C and a
stoichiometric amount of base under anaerobic conditions.
Shvo and co-workers have reported the reaction of the
hydride-bridged complex 1 with methyl iodide to give three
products: the iodide-bridged diruthenium species 4, (η5-
Ph4C4COH)(CO)2RuI (2c), and (η5-Ph4C4COMe)(CO)2RuI
(5) (Scheme 2). Although they isolated 4 only in a trace
amount, they succeeded in determining its molecular struc-
ture by X-ray diffraction analysis, with which they proposed
that 4 is an unusual neutral complex containing two Ru1/2þ
and a single iodide bridge.12
Shvo’s complex 1 exhibits intriguing catalytic activities for
many hydrogen-transfer reactions such as hydrogenation of
alkynes,1,2 reduction of ketones,3 oxidation of alcohols,4
Tishchenko-type disproportionation of aldehydes,5 and oxi-
dant-free dehydrogenation of alcohols.6 Moreover, it is also
an excellent catalyst for the racemization of secondary
alcohols under the conditions for the dynamic kinetic resolu-
tion (DKR) of alcohols with enzymes and acylating re-
€
7
agents. Recently, Backvall and co-workers have reported
its activity also for the racemization of amines.8 However,
We became interested in the structure of 4 and its catalytic
activity because the presence of two units of 3 may greatly
enhance its catalytic activity. Another interesting point is
that the structure of 4 does not obey the 18-electron rule.
Herein we report the formation of iodide-bridged diruthe-
nium complex 6a from 2c and a dimer of 3, [(Ph4C4CO)
(CO)2Ru]2 (7a). The structure of 6a resembles that of 4, but
obeys the 18-electron rule. Furthermore, in our present
study, 6a turned out to be a more efficient catalyst than
Shvo’s complex (1) for the oxidation of alcohols with silver
oxide under mild conditions (Scheme 3). For example, 1-
phenylethanol was completely oxidized within 4 h at room
temperature when a catalytic amount of 6a (2 mol % of Ru)
and 1 equiv of silver oxide were used.
*Corresponding author. E-mail: pjw@postech.ac.kr.
(1) Shvo, Y.; Czarkie, D.; Rahamim, Y.; Chodosh, D. F. J. Am.
Chem. Soc. 1986, 108, 7400.
(2) Shvo, Y.; Goldberg, I.; Czarkie, D.; Reshef, D.; Stein, Z. Orga-
nometallics 1997, 16, 133.
(3) (a) Shvo, Y.; Czarkie, D. J. Organomet. Chem. 1986, 315, C25.
(b) Menashe, N.; Salant, E.; Shvo, Y. J. Organomet. Chem. 1996, 514, 97.
€
(4) (a) Wang, G.-Z.; Andreasson, U.; Backvall, J.-E. J. Chem. Soc.,
€
Chem. Commun. 1994, 1037. (b) Karlsson, U.; Wang, G.-Z.; Backvall, J.-E.
ꢀ
€
J. Org. Chem. 1994, 59, 1196. (c) Almeida, M. L. S.; Kocovsky, P.; Backvall,
ꢁ
J.-E. J. Org. Chem. 1996, 61, 6587. (d) Csjernyik, G.; Ell, A. H.; Fadini, L.;
Pugin, B.; Backvall, J.-E. J. Org. Chem. 2002, 67, 1657.
€
(5) Menashe, N.; Shvo, Y. Organometallics 1991, 10, 3885.
(6) (a) Blum, Y.; Shvo, Y. J. Organomet. Chem. 1985, 282, C7.
(b) Choi, J. H.; Kim, N.; Shin, Y. J.; Park, J. H.; Park, J. Tetrahedron Lett.
2004, 45, 4607.
€
(7) (a) Larsson, A. L. E.; Persson, B. A.; Backvall, J.-E. Angew.
The reaction mixture of 2c and 7a in the mole ratio of 2:1
was purified by column chromatography with silica gel, and
the major product was recrystallized to give X-ray quality
crystals. Unexpectedly, the X-ray diffraction analysis of the
Chem., Int. Ed. Engl. 1997, 36, 121. (b) Persson, B. A.; Larsson, A. L. E.;
Ray, M. L.; Backvall, J.-E. J. Am. Chem. Soc. 1999, 121, 1645. (c) Verzijl,
€
G. K. M.; de Vries, J. G.; Broxterman, Q. B. PCT Int. Appl. 2001, WO 2001
090396.(d) Verzijl, G. K. M.; de Vries, J. G.; Broxterman, Q. B. Tetrahedron:
Asymmetry 2005, 16, 1603.
ꢁ
ꢂ
(8) (a) Pamies, O.; Ell, A. H.; Samec, J. S. M.; Hermanns, N.;
€
€
Backvall, J.-E. Tetrahedron Lett. 2002, 43, 4699. (b) Paetzold, J.; Backvall,
J.-E. J. Am. Chem. Soc. 2005, 127, 17620.
(10) (a) Casey, C. P.; Johnson, J. B. J. Am. Chem. Soc. 2005, 127,
1883. (b) Casey, C. P.; Bikzhanova, G. A.; Guzei, I. A. J. Am. Chem. Soc.
2006, 128, 2286. (c) Casey, C. P.; Clark, T. B.; Guzei, I. A. J. Am. Chem. Soc.
2007, 129, 11821.
(11) Jung, H. M.; Choi, J. H.; Lee, S. O.; Kim, Y. H.; Park, J. H.;
Park, J. Organometallics 2002, 21, 5674.
(9) (a) Casey, C. P.; Singer, S. W.; Powell, D. R.; Hayashi, R. K.;
Kavana, M. J. Am. Chem. Soc. 2001, 123, 1090. (b) Casey,
C. P.; Johnson, J. B.; Singer, S. W.; Cui, Q. J. Am. Chem. Soc. 2005, 127,
3100. (c) Casey, C. P.; Strotman, N. A.; Beetner, S. E.; Johnson, J. B.; Priebe,
D. C.; Vos, T. E.; Khodavandi, B.; Guzei, I. A. Organometallics 2006, 25,
1230. (d) Casey, C. P.; Strotman, N. A.; Beetner, S. E.; Johnson, J. B.; Priebe,
D. C.; Guzei, I. A. Organometallics 2006, 25, 1236.
(12) Schneider, B.; Goldberg, I.; Reshef, D.; Stein, Z.; Shvo, Y.
J. Organomet. Chem. 1999, 588, 92.
r
pubs.acs.org/Organometallics
Published on Web 06/25/2009
2009 American Chemical Society

Note
Organometallics, Vol. 28, No. 15, 2009 4625
Scheme 2. Reaction of the Shvo Complex with Methyl Iodide
symmetrical structures; only one peak (6a, δ 199.4 ppm; 6b, δ
199.9 ppm) for the carbonyl carbons was observed. Further-
more, two peaks for CO stretching (6a, 2026 and 1970 cm-1
;
6b, 2028 and 1977 cm-1) were observed in the IR spectra.
Although a symmetrical structure similar to that of 1 is not
plausible considering the long distance between the two
oxygen atoms of the Cp rings,17 the spectral data of 6a and
6b can be reasonably explained by fast proton transfer
between the oxygen atoms of the Cp rings.
Figure 1. ORTEP drawing of 8 (50% probability). Phenyl
substituents of cyclopentadienone rings, hydrogen atoms, and
the cocrystallized water molecules are omitted for clarity.
˚
Selected bond lengths (A) and angles (deg): I1-Ru1 2.6861(4),
I1-Ru2 2.6848(4), Ca1-O4 2.26857(3), Ru1-C1 2.4757(4),
Ru1-C2 2.2473(4), Ru1-C3 2.1866(4), Ru1-C4 2.1878(4),
Ru1-C5 2.2546(4), C1-O1 1.2520(5), C32-O4 1.2568(5),
Ru2-C32 2.4531(4), Ru2-C33 2.2571(4), Ru2-C34 2.1901
(4), Ru2-C35 2.1922(4), Ru2-C36 2.2463(4); Ru2-I1-Ru1
126.00(2), O4-Ca1-O8 93.0(2), O4-Ca1-O7 95.5(1), O8-
Ca1-O7 81.8(2).
The catalytic activities of 6a and 6b were tested for the
oxidation of various alcohols with silver oxide as a stoichio-
metric oxidant. It is worth noting that anaerobic conditions
are not required for this oxidation. A combination of 2 mol
% of 6a and 1.0 equiv of Ag2O completely oxidized 1-
phenylethanol to acetophenone within 4 h at room tempera-
ture with the formation of silver mirror and Shvo’s complex
(1). In contrast, that oxidation was not possible with Ag2O
alone, and the oxidation using Shvo’s complex was signifi-
cantly less efficient.18 Inorganic bases (K2CO3 and K3PO4)
and metal oxides (Na2O, Cu2O, MgO, and ZnO) were not
effective for the oxidation. The activity of our catalyst system
for benzylic and aliphatic alcohols is summarized in Table 1.
Secondary alcohols are converted selectively into the corre-
sponding ketones (entries 1-3). Benzyl alcohol is oxidized
into benzaldehyde in high yields (entry 4). In contrast, 1-
octanol is converted into octyl octanoate (entry 5).19 In all of
the cases, the catalytic activity of 6a is much higher than that
of 6b.
One possible mechanism for the catalytic oxidation is
presented in Scheme 4. The active species 3 is liberated from
6a. Complex 3 oxidizes alcohols to ketones with the forma-
tion of the ruthenium hydride 2a, which is oxidized by Ag2O
with the formation of Ag metal. Meanwhile, 2c can also
participate in the catalytic cycle through the reaction with
Ag2O to generate 3.20 After the consumption of silver oxide,
2a and 3 combine to form the thermodynamically stable 1.9a
In summary, we have found a simple and efficient syn-
thetic route to iodide-bridged diruthenium complexes that
exhibit high catalytic activity for the oxidation of various
alcohols with silver oxide under mild conditions. On the basis
of the X-ray diffraction analysis for our ruthenium
Scheme 1. Dissociation of the Shvo Complex
crystals revealed the structure of a tetranuclear ruthenium
complex (8), which might have been formed from two units
of 6a through deprotonation and bridging with a calcium
cation (Figure 1).13 The identity of the Ca2þ ion was con-
firmed by ICP,14 and this ion was believed to come from
silica gel used for column chromatography.15 The formal
oxidation states of Ru(1), Ru(2), I, and Ca are assigned as
0, þ2, -1, and þ2, respectively, with which each Ru metal in
8 satisfies the 18-electron rule. The central Ca(H2O)24þ frag-
ment formally replaces the two hydroxy protons on the Cp
rings in the neighboring [Ru2] units. It is noticeable that all
the bonding parameters in the I-bridged diruthenium unit of
8 are essentially the same as those of 4 reported by Shvo’s
group.12,16 Subsequently, an analogue (6b) of 6a could be
synthesized from [2,5-Me2-3,4-Ph2(η5-C4COH)(CO)2RuI
(2d) and [2,5-Me2-3,4-Ph2(C4CO)(CO)2Ru]2 (7b) and struc-
turally characterized by X-ray diffraction analysis (Figure 2).
The molecular structure of 6b shows clearly that a half of 7b
is bonded to the iodine atom of 2d.
The complexes 6a and 6b were further characterized by IR
and NMR.16 The simple 13C NMR spectra suggest their
(13) Despite the presence of an intervening octahedral calcium frag-
ment, the Ru-I-Ru bond angle (126.00(2)°) in 8 is practically the same
as that (125.97(2)°) found in the analogous structure of 4 in Scheme 2.
(14) ICP analysis revealed that the calcium content of crystalline 8 is
1.51 wt %. The measured calcium content of the crystals is consistent
with the calculated value (1.46 wt %) for C124H80CaI2O12Ru4 6H2O 2
(17) The distances between two oxygen atoms of the Cp rings in 6b
˚
and 8 are 5.44 and 4.92 A, respectively.
(18) When 2 mol % of Shvo’s complex was used in the oxidation,
acetophenone was formed only in 20% yield after 3 h. However, when 1
mol % of 8 was used in the oxidation, 89% of acetophenone was formed
after 3 h.
(19) Aldehyde can react with alcohol to give the corresponding
hemiacetal, which is subsequently oxidized into the ester.
(20) When we used 2c (4 mol %) instead of 6a in the oxidation of 1-
phenylethanol under the conditions of Table 1, acetophenone was
obtained in quantitative yield in 3 h.
3
3
CH2Cl2.
(15) The silica gel used for the purification of 6a was analyzed by ICP,
which showed the calcium content to be 0.106 wt %. When 6a was
filtered through a CaSiO3 pad, 8 was obtained quantitatively.
(16) See Supporting Information.

4626 Organometallics, Vol. 28, No. 15, 2009
Do et al.
Scheme 3. Reaction of (η5-Ph4C4COH)Ru(CO)2I with [(Ph4C4CO)Ru(CO)2]2
washed with hexane, to give 6a as yellow-brown solid (347.5 mg,
1
>96% yield). Mp: 162 °C dec. H NMR (300 MHz, CDCl3):
δ 7.25-6.94 (m, 40H). 13C NMR (75 MHz, CDCl3): δ 199.4 (Ru-
CO), 132.4, 132.0, 131.8, 130.9, 130.5, 130.3, 129.4, 128.6, 128.5,
128.1, 128.1, 128.0, 127.8, 127.7, 127.4, 127.0, 101.4 (C2,5 of Cp),
87.1 (C3,4 of Cp). IR (KBr, cm-1): ν(CO) 2026 (s), 1970 (s). FAB
MS: m/z 1213.0 (M þ H).
Synthesis of [2,5-Me2-3,4-Ph2(η5-C4COH)](CO)2RuI (2d). In
a 50 mL flask equipped with a grease-free high-vacuum
stopcock, [2,5-Me2-3,4-Ph2(η4-Ph4C4CO)]Ru(CO)3 (250 mg,
0.561 mmol) and CHI3 (1.5 equiv) were dissolved in 2-propanol
(5 mL) and toluene (15 mL) under argon. The solution was
heated to reflux for 10 h. The reaction mixture was concen-
trated, and the resulting crude product was purified by column
chromatography (hexane/ethyl acetate=1:1) to give 2d as an
Figure 2. ORTEP drawing of 6b (50% probability). Phenyl
substituents of cyclopentadienone rings, hydrogen atoms except
the hydroxyl proton, and the cocrystallized dichloromethane
1
orange solid (292 mg, 95% yield). Mp: 168 °C dec. H NMR
(300 MHz, CDCl3): δ 7.27-7.15 (m, 10H), 2.12 (s, 6H). 13C
NMR (75 MHz, CDCl3): δ 197.9 (Ru-CO), 134.2 (C1 of Cp),
131.6, 129.8, 128.8, 128.4, 101.4 (C2,5 of Cp), 87.0 (C3,4 of Cp),
9.6 (CH3 of C2,5). IR (KBr, cm-1): ν(CO) 2026 (s), 1973 (s). MS
(FAB, m/z): 545.9 (Mþ). Anal. Calcd for C21H17IO3Ru: C,
46.25; H, 3.14. Found: C, 46.39; H, 3.26.
˚
molecules are omitted for clarity. Selected bond lengths (A) and
angles (deg): I1-Ru1 2.7245(2), I1-Ru2 2.7062(2), Ru1-C1
2.4154(5), Ru1-C2 2.2397(5), Ru1-C3 2.1895(5), Ru1-C4
2.1959(5), Ru1-C5 2.2483(5), C1-O1 1.2844(6), C22-O4
1.3136(5), Ru2-C22 2.3580(5), Ru2-C23 2.2456(5), Ru2-
C24 2.2139(5), Ru2-C25 2.1848(5), Ru2-C26 2.2529(5),
Ru2-I1-Ru1 118.21(6).
Synthesis of [(η5-2,5-Me2-3,4-Ph2C4COH)(CO)2RuIRu(η4-
2,5-Me2-3,4-Ph2C4CO)(CO)2)] (6b). In a 50 mL flask equipped
with a grease-free high-vacuum stopcock, [2,5-Me2-3,4-Ph2(η5-
C4COH)](CO)2RuI (2d) (100.0 mg, 0.183 mmol) and
[(Me2Ph4C4CO)(CO)2Ru]2 (7b) (76.4 mg, 0.091 mmol) were
dissolved in CH2Cl2 (20 mL) under argon. The solution was
stirred at room temperature for 1 h. The reaction mixture was
concentrated, and the resulting crude product was washed with
hexane, to give 6b as a yellow-brown solid (161 mg, >91%
complexes, we have suggested a more reasonable structure
than the previous one that has been reported to contain two
Ru1/2þ centers.
Experimental Section
1
yield). Mp: 157 °C dec. H NMR (300 MHz, CDCl3): δ 7.19
All anaerobic and moisture-sensitive manipulations were
carried out with standard Schlenk techniques under argon.
Commercial chemicals were used without further purification.
Flash column chromatography was carried out on silica gel
(230-400 mesh) as the stationary phase. 1H NMR and 13C
NMR spectra were recorded with a 300 MHz instrument. FT-IR
spectra were obtained with KBr pellets. The ruthenium com-
plexes, 1,1 2c,12 7a,21a 7b,21a [(η4-Ph4C4CO)(CO)3Ru],21b and
[(η4-2,5-Me2-3,4-Ph2C4CO)(CO)3Ru],21b were synthesized ac-
cording to the literature procedures.
(s, 20H) 2.22 (s, 12H). 13C NMR (75 MHz, CDCl3): δ 199.9 (Ru-
CO), 153.6 (C1of Cp), 131.4, 130.9, 128.2, 128.1, 100.9 (C2,5 of
Cp), 84.7 (C3,4 of Cp). IR (KBr, cm-1): ν(CO) 2028 (s), 1977 (s).
FAB MS: m/z 964.9492 (M þ H).
Synthesis of [(η4-Ph4C4CO)(CO)2RuIRu(η4-Ph4C4CO)(CO)2]2-
Ca(H2O)4 (8). In a 10 mL flask equipped with a grease-free high-
vacuum stopcock, (η5-Ph4C4COH)(CO)2RuI (100 mg, 0.073
mmol) and [(Ph4C4CO)Ru(CO)2]2 (85 mg, 0.073 mmol) were
dissolved in dichloromethane (10 mL) under argon. The solution
was stirred at room temperature for 6 h. The reaction mixture was
concentrated, and the resulting crude product was purified by
column chromatography (hexane/ethyl acetate=1:1) to give 8 as a
Synthesis of [(η5-Ph4C4COH)(CO)2RuIRu(η4-Ph4C4CO)
(CO)2] (6a). In a 50 mL flask equipped with a grease-free
high-vacuum stopcock, (η5-Ph4C4COH)(CO)2RuI (2c) (200.0
mg, 0.298 mmol) and [(η5-Ph4C4CO)(CO)2Ru]2 (7a) (161.6 mg,
0.149 mmol) were dissolved in CH2Cl2 (20 mL) under argon. The
solution was stirred at room temperature for 1 h. The reaction
mixture was concentrated, and the resulting crude product was
1
yellow solid (170 mg, 95% yield). Mp: 198 °C dec. H NMR
(300 MHz, CDCl3): δ 7.21-6.97 (m, 80H), δ 2.99 (s, 8H). 13C
NMR (75 MHz, CDCl3): δ 200.13 (Ru-CO), 132.1, 131.8, 131.6,
127.8, 127.6, 126.8 (C1 of Cp), 101.2 (C2,5 of Cp), 84.3 (C3,4 of
Cp). IR (KBr, cm-1): ν(CO) 3425 (b), 2023 (s), 1979 (s), 1545 (s).
Structure Analysis of [(η4-Ph4C4CO)(CO)2RuIRu(η5-Ph4C4-
CO)(CO)2]2Ca(H2O)6(CH2Cl2)2. The crystal was obtained by
layering of hexane into a dichloromethane solution of the
complex. A suitable crystal was mounted onto a specially
(21) (a) Mays, M. J.; Morris, M. J.; Raithby, P. R.; Shvo, Y.; Czarkie,
D. Organometallics 1989, 8, 1162. (b) Bruce, M. I.; Knight, J. I.
J. Organomet. Chem. 1968, 12, 412.

Note
Organometallics, Vol. 28, No. 15, 2009 4627
Table 1. Oxidation of Alcoholsa
a Alcohol (0.25 mmol) was added to a suspension of 6 (2.0 mol %) and Ag2O (1.0 equiv) in CH2Cl2 (0.5 mL), and the resulting mixture was stirred at
room temperature in air. b Determined by GC. c Numbers in parentheses show isolation yields.
with 15 021/0/680 data/restraints/parameters and GOF=1.024.
Scheme 4. Proposed Pathway for the Ru-Catalyzed Oxidation of
Alcohols
3
˚
The largest peak and hole were 1.282 and -0.724 e/A .
Structure Analysis of [(η5-2,5-Me2-3,4-Ph2C4COH)(CO)2
RuIRu(η4-2,5-Me2-3,4-Ph2C4CO)(CO)2](CH2Cl2)2. The crystal
was obtained by layering of hexane into a dichloromethane
solution of the complex at -40 °C. A suitable crystal was
mounted onto a specially constructed apparatus with cooling
in an inert atmosphere on a diffractometer and analyzed.
Structure solution and refinement was carried out with the
SHEKXLX programs. Crystal data for 6b: C44H37Cl4IO6Ru2,
Mw 1132.58, yellow-brown, crystal size (0.28 ꢀ 0.22 ꢀ 0.18),
˚
monoclinic, space group P121/c1, a=16.104(14) A, b=16.875
o
˚
˚
(15) A, c=17.228(15) A, R=90°, β=104.437(15) , γ=90°, V=
4534(7) A , Z=4, Dcalcd=1.659 Mg m-3, F(000)=2232, T=243
3
˚
(2) K, μ=1.627 mm-1, 26 009 measured reflections, 9255 unique
reflections (Rint = 0.0345), minimum/maximum transmission
factors 0.7583/0.6586. The final agreement factors were R1=
0.0456 (I > 2σ(I) and wR2 = 0.1327, with 9255/0/519 data/
restraints/parameters and GOF=1.015. The largest peak and
3
˚
hole were 2.065 and -1.130 e/A .
Acknowledgment. We are grateful for the financial
support from KOSEF (R01-2006-000-10696-0) and the
Korean Ministry of Education and Human Resources
through KRF (BK21 program).
constructed apparatus with cooling in an inert atmosphere on a
diffractometer and analyzed. Structure solution and refinement
was carried out with the SHEKXLX programs. Crystal data for
8: C126H96CaCl4I2O18Ru4, Mw 2737.99, brown, crystal size (0.32
ꢀ
0.28
ꢀ
0.26), monoclinic, space group P21/n,
˚
˚
˚
Supporting Information Available: Experimental procedures,
characterization data for 2c, 2d, 6a, 6b, 7a, 7b, and 8; summaries
of structure determination and listings of final atomic coordi-
nates, thermal parameters, bond lengths, and bond angles for 8
and 6b. This material is available free of charge via the Internet
at http://pubs.acs.org.
a=15.6348(2) A, b=16.9401(2) A, c=23.1628(3) A, R=90°,
o
3
˚
β=95.5930(10) , γ=90°, V=6105.58(13) A , Z=2, Dcalcd=1.486
g cm-3, F(000)=2720, T=296(2) K, μ=1.183 mm-1, 119601
measured reflections, 15 021 unique reflections (Rint = 0.0414),
minimum/maximum transmission factors 0.7485/0.7034. The final
agreement factors were R1=0.0482 (I > 2σ(I) and wR2=0.1194,