Synthesis and structure of new diarene-bridged bi- and polymetallic compounds

Article abstract of DOI:10.1016/S0020-1693(96)05577-6

Phenylcyclopentadiene (2) and diphenylcyclopentadiene (10) have been used to make bi- and polymetallic compounds. Compounds 2 and 10 have been used to make Cr-Fe bimetallic (5), Fe-Cr₂ trimetallic (6), Cr-Mn-Fe trimetallic (7), Fe-Mn₂

Full text of DOI:10.1016/S0020-1693(96)05577-6

Inorganica Chimica Acta 261 (1997) 37–44
Synthesis and structure of new diarene-bridged bi- and
polymetallic compounds
U
Youn Kyung Kang a, Hee-Kyu Lee a, Su Seong Lee a, Young Keun Chung a, , G. Carpenter b
a Department of Chemistry and Center for Molecular Catalysis, College of Natural Sciences, Seoul National University, Seoul 151-742, South Korea
b Department of Chemistry, Brown University, Providence, RI 02912, USA
Received 4 July 1996; revised 7 October 1996; accepted 29 October 1996
Abstract
Phenylcyclopentadiene (2) and diphenylcyclopentadiene (10) have been used to make bi- and polymetallic compounds. Compounds 2
and 10 have been used to make Cr–Fe bimetallic (5), Fe–Cr2 trimetallic (6), Cr–Mn–Fe trimetallic (7), Fe–Mn2 trimetallic (8), Mn–Cr
bimetallic (12), Cr–Mn2 trimetallic (13), Fe2 bimetallic (15) and Fe–Cr4 pentametallic (17) compounds. The molecular structures of 8 and
12 have been determined by X-ray crystallography.
Keywords: Diarene complexes; Polymetallic complexes; Crystal structures
1. Introduction
and quarter-cyclopentadienylsandtheirtransitionmetalcom-
plexes. Ligands of these types will be able to hold several
metals in close proximity, thereby allowing researchers to
investigate whether cooperative effects can enhance or mod-
ify the chemical reactivity of metal complexes with regard to
the mono-Cp analogs. This could result in new multimetal
catalysts [12], organometallic polymers [13], heteropoly-
metallics [14], or redox active compounds [15].
Herein, we report the syntheses and structures of bi- and
polymetallic compounds bridged by phenylcyclopentadienyl
and 1,3-diphenylcyclopentadienyl ligands. The chemistry
related to the use of phenylcyclopentadienylthallium has
been previously reported by Rausch and co-workers [16].
However, they only reported cyclopentadienyl complexes.
Cyclopentadienyl ligands are one of the most popular
ligands in organometallic chemistry, and complexesofcyclo-
pentadienyl ligands are known for all transition and most f-
block metals [1]. Cyclopentadienyl ligands have been
synthesized by various methods [2]. One of the strategies
used to synthesize cyclopentadienyl metal compounds is the
use of cyclopentenone asa startingmaterial[3]. ThePauson–
Khand reaction is one of the most effective methods in the
syntheses of cyclopentenones [4]. Recently, we reported the
preparation of 1,2-disubstituted or 1,2,3-trisubstituted cyclo-
pentadienyl ligands from the Pauson–Khand reaction prod-
ucts [5], opening up a more general route to the preparation
of various cyclopentadienyl ligands.
Substituted cyclopentadienyl complexes differ greatly
from their unsubstituted counterparts in reactivity, structural
features and physical properties [6]. As a result, many
researchers have concentrated their efforts to synthesize
highly substituted cyclopentadienyl ligands [7]. However,
much less is known about the use of highly substituted cyclo-
pentadienyl ligands to prepare bi- and polymetallic com-
pounds. Recently, bimetallic compounds linked by pairs of
cyclopentadienyl moieties, as in fulvalene [8], fluorene [9]
and indenyl [10], have been reported. Vollhardt and co-
workers [11] reported the synthesis and reactions of the ter-
2. Experimental
All reactions were conducted under nitrogen using stan-
dard Schlenk type flask and cannula techniques. Workup
procedures were done in air.
Elemental analyses were done at the Chemical Analytic
Center, College of Engineering, Seoul National University.
1H NMR spectra were obtained with a Varian XL-200 instru-
ment. IR spectra were recorded on a Shimadzu IR-470 (spec-
tra measured as films on NaCl by evaporation of solvent).
Mass spectra were recorded with a VG ZAB-E double-
focusing mass spectrometer.
U Corresponding author. Fax: (international code)-02-889-1568; e-mail:
ykchung@plaza.snu.ac.kr
0020-1693/97/$17.00 q 1997 Elsevier Science S.A. All rights reserved
PII S0020-1693(96)05577-6

38
Y.K. Kang et al. / Inorganica Chimica Acta 261 (1997) 37–44
Compounds 1, 9, 10 and [(naphthalene)Mn(CO)3]BF4
2.4. Synthesis of 7
were synthesized according to the published procedures
[5,17,18]. Compound 10 was previously published [19].
Compound 5 (0.065 g, 0.14 mmol) and [(naphtha-
lene)Mn(CO)3]BF4 (0.05 g, 0.14 mmol) were dissolved in
20 ml of CH2Cl2. The solution was refluxed for 3 h under
dark. After cooling to room temperature, the solution was
filtered through celite. The filtrate was added to 50 ml of
diethyl ether to precipitate the product. The analytically pure
red crystalline product was recrystallized from CH3NO2/di-
ethyl ether. The yield was 32% (0.028 g). IR (CsF): n(CO)
2072, 2020, 1963, 1888 cmy1. 1H NMR (CD3NO2): d 6.68
(t, 6.7 Hz, 1H), 6.37 (d, 6.7 Hz, 2H), 6.29 (t, 6.7 Hz, 2H),
5.63 (m, 4H), 5.49 (m, 1H ), 5.03 (br. s, 2H), 4.83 (br. s,
4H), 4.51 (br. s, 2H) ppm. FAB mass (low resolution):
MqyCr(CO)3 477, Cr(CO)3q 136.
2.1. Synthesis of 3
Compound 2 (0.66 g, 4.6 mmol) and Mn2(CO)10 (2.0 g,
5.1 mmol) were dissolved in 30 ml of xylene. The solution
was refluxed for 2 days. After cooling to room temperature,
the solvent was removed, and the residue was extracted with
diethyl ether. The etheral solution was filtered through celite.
The filtrate was concentrated and column chromatographed
on silica gel eluting with hexane. After purification, bright
yellow oil was obtained in 50% (0.64 g) yield. IR (NaCl):
1
n(CO) 2020, 1920 cmy1. H NMR (CDCl3): d 7.42–7.26
(m, 5H), 5.19 (t, 2.2 Hz, 2H), 4.78 (t, 2.2 Hz, 2H) ppm.
HRMS: Mq calc. 279.9932, obs. 279.9934.
2.5. Synthesis of 8
2.2. Synthesis of 4
Compound 4 (0.050 g, 0.15 mmol) and [(naphtha-
lene)Mn(CO)3]BF4 (0.105 g, 0.30 mmol) were dissolved
in 20 ml of CH2Cl2. The solution was refluxed for 3 h under
dark. After cooling to room temperature, the solution was
filtered through celite. The filtrate was added to 50 ml of
diethyl ether to precipitate the product. The analytically pure
red crystalline product was recrystallized from CH3NO2/di-
ethyl ether. The yield was 45% (0.053 g). IR (CsF): n(CO)
Compound 2 (0.165 g, 1.15 mmol) was dissolved in 20
ml of THF. The solution was cooled to 08C. To the cold THF
solution n-BuLi (0.5 ml, 2.5 M solution) was added drop-
wise. The resulting solution was stirred at 08C for 1 h. FeCl2
(0.10 g, 0.8 mmol) was dissolved in 20 ml of THF. After
refluxing for 1 h, the THF solution was cooled to 08C and
kept in an ice bath, inducing the precipitation of white pre-
cipitates (FeCl2(THF)n). The brown supernatant solution
was removed and 5 ml of fresh THF solution were added to
the precipitates. The lithium anionic solution was added via
cannulation to the THF solution of FeCl2(THF)n. The result-
ing solution wasrefluxedovernight. Aftercooling,thesolvent
was removed and the residue was extractedwithdiethylether.
The etheral solution was filtered through celite. The filtrate
was concentrated and column chromatographed. After puri-
fication, orange crystalline solids were obtained in 92% (0.18
g) yield. 1H NMR (CDCl3): d 7.22–7.16 (m, 10H), 4.62 (t,
1.5 Hz, 4H), 4.46 (t, 1.5 Hz, 4H) ppm. Anal. Calc. for
C22H18Fe: C, 78.12; H, 5.36. Found: C, 77.64; H, 5.48%.
1
2076, 2020 cmy1. H NMR (CD3NO2): d 6.78 (t, 6.1 Hz,
4H), 6.51 (d, 6.1 Hz, 4H), 6.40 (t, 6.7 Hz, 2H), 5.11 (br. s,
4H), 4.83 (br. s, 4H) ppm. Anal. Calc. for C25H18B2-
F8Mn2O6: C, 42.58; H, 2.30. Found: C, 42.03; H, 2.24%.
Analytical data for 9. 1H NMR (CDCl3): d 7.77–7.11 (m,
11H), 3.79–3.74 (dd, 7.1, 2.9 Hz, 1H), 3.34–3.19(ddd, 19.8,
7.1, 3.2 Hz, 2H), 2.89–2.76 (ddd, 19.8, 2.9, 2.7 Hz, 2H)
ppm. HRMS: Mq calc. 234.1045, obs. 234.1216.
Analytical data for 10. 1H NMR (CDCl3): major isomer,
d 7.65–7.12 (m, 10H), 6.94 (t, 1.2 Hz, 2H), 3.79 (t, 1.2 Hz,
2H) ppm; minor isomer, 7.65–7.12 (m, 10H), 6.65 (td, 1.9,
1.7 Hz, 1H), 3.60 (dd, 1.9, 1.0 Hz, 2H) ppm.
2.3. Synthesis of 5
2.6. Synthesis of 11
Compound 4 (0.15 g, 0.44 mmol) and Cr(CO)6 (0.10 g,
0.48 mmol) were dissolved in 12 ml of a mixed solvent of
Bu2O and THF (vol./vol. 10:1). The solution was refluxed
for 3 days. After cooling to room temperature, the solvent
was removed, and the residue was extracted with diethyl
ether. The etheral solution was filtered through celite. The
filtrate was concentrated and column chromatographed on
silica gel eluting with hexane and diethyl ether (vol./vol.
20:1). After purification, orange crystalline solids were
obtained in 77% (0.16 g) yield. IR (CsF): n(CO) 1959,
1883 cmy1. 1H NMR (CDCl3): d 7.36–7.18 (m, 5H), 5.31–
5.11 (m, 5H), 4.59 (t, 1.83 Hz, 2H), 4.36 (t, 1.83 Hz, 2H),
4.31 (t, 1.83 Hz, 4H) ppm. Anal. Calc. for C25H18CrFeO3:
C, 63.31; H, 3.83. Found: 62.66; H, 3.83%.
Compound 10 (0.186 g, 0.85 mmol) and Mn2(CO)10
(0.432 g, 1.10 mmol) were dissolved in 30 ml of xylene. The
solution was refluxed for 2 days. After cooling to room tem-
perature, the solvent was removed, and the residue was
extracted with diethyl ether. The etheral solution was filtered
throughcelite. Thefiltratewasconcentratedandcolumnchro-
matographed on silica gel eluting with hexane. After purifi-
cation, bright yellow solids were obtained in 64% (0.19 g)
yield. IR (NaCl): n(CO) 2016, 1925 cmy1 1H NMR
.
(CDCl3): d 7.54–7.26 (m, 10H), 5.67 (t, 1.8 Hz, 1H), 5.24
(d, 1.8 Hz, 2H) ppm. Anal. Calc. for C20H13MnO3: C, 67.42;
H, 3.69. Found: 67.19; H, 3.64%.

Y.K. Kang et al. / Inorganica Chimica Acta 261 (1997) 37–44
39
2.7. Syntheses of 12 and 13
(br. s, 20H), 4.62 (t, 3.75 Hz, 2H), 4.45 (d, 3.75 Hz, 4H)
ppm. Anal. Calc. for C34H26Fe: C, 83.27; H, 5.34. Found:
82.92; H, 5.26%.
Compound 11 (0.184 g, 0.52 mmol) and Cr(CO)6 (0.114
g, 0.52 mmol) were dissolved in 12 ml of n-Bu2O and THF
(vol./vol. 10:1). The solution was refluxed for 3 days. After
cooling to room temperature, the solvent was removed, and
the residue was extracted with diethyl ether. The etheral solu-
tion was filtered through celite. The filtrate was concentrated
and column chromatographed on silica gel eluting with a
mixture solvent of hexane and ethylacetate (vol./vol. 20:1).
After purification, 12 and 13 were obtained in the ratio of
60% (0.15 g) and 15% (0.05 g). When 4 equiv. of Cr(CO)6
were used, 12 and 13 were obtained in the ratio of 20% and
43%.
2.10. Synthesis of 17
Compound 16 (0.10 g, 0.20 mmol) and Cr(CO)6 (1.0 g,
4.5 mmol) were dissolved in a mixed solvent of n-Bu2O (50
ml) and THF (10 ml). The solution was refluxed for 3 days.
During refluxing, orange solids were precipitated. The solu-
tion was cooled to room temperature andtheprecipitateswere
filtered off. The precipitates were washed with diethyl ether
(10 ml=3) and then washed with CH2Cl2 (5 ml=2). The
purified product was obtained by recrystallization from ace-
1
Analytical data for 12. IR (NaCl): n(CO) 2024, 1968,
1938, 1890 cmy1. 1H NMR (CDCl3): d 7.50–7.34 (m, 5H),
5.58–5.20 (m, 8H) ppm. Anal. Calc. for C23H13CrMnO6: C,
56.12; H, 2.66. Found: C, 55.80; H, 2.89%.
tone/hexane. The yield was 78% (0.14 g). H NMR (d6-
acetone): d 5.85–5.45 (m, 22H), 5.00 (d, 1.4 Hz, 4H) ppm.
Anal. Calc. for C46H26Cr4FeO12: C, 53.41; H, 2.53. Found:
54.01; H, 2.28%.
Analytical data for 13. IR (NaCl): n(CO) 2020, 1968,
1938, 1892 cmy1. 1H NMR (CDCl3): d 5.48–5.30 (m, 10H),
5.29 (s, 1H), 5.17 (d, 1.8 Hz, 2H) ppm. HRMS: Mq calc.
627.8750, obs. 627.8770.
2.11. X-ray structure determination of 8
A crystal of 8 having approximate dimensions of
0.50=0.20=0.10 mm was mounted on a glass fiber. Prelim-
inary examination and data collection were performed with
2.8. Syntheses of 14 and 15
˚
Mo Ka radiation (ls0.71073 A) on an Enraf-Nonius
Compound 10 (0.047 g, 0.21 mmol) and Fe2(CO)9 (0.20
g, 0.55 mmol) were dissolved in 30 ml of benzene. The
solution was refluxed for 6 h. After cooling to room temper-
ature, the solvent was removed, and the residue was extracted
with diethyl ether. The etheral solution was filtered through
celite. The filtrate was concentrated and column chromato-
graphed on silica gel eluting with hexane and hexane/ethyl
acetate (vol./vol. 10:1). After purification, bright yellow
solids 14 and 15 were obtained in 57% (0.05 g) and 28%
(0.04 g) yield, respectively.
CAD4 computer controlled kappa axis diffractometer
equipped with a graphite crystal monochromator. Cell con-
stants and an orientation matrix for data collection were
obtained from least-squares refinement, using the setting
angle of 25 reflections in the range 2.03-u-22.488, meas-
ured by the computer controlled diagonal slit method of cen-
tering. The data were collected at room temperature using the
omega scan technique. A total of 1733 unique reflections was
collected. Lorentz and polarization corrections were applied
to the data. No absorption correction was applied to the data.
The structure was solved by direct method using SHELXS-
86 [20] and refined by full-matrix least-squares with
SHELXL-93 [21]. All non-hydrogen atoms were refined
anisotropically; hydrogen atoms were refined isotropically
using a riding model with 1.2 times the equivalent isotropic
temperature factors of the atoms to which they are attached.
The anion tetrafluoroborate is disordered. Crystaldata,details
of the data collection, and refinement parameters for 8 are
listed in Table 1. Final atomic positional parameters for the
non-hydrogen atoms are shown in Table 2, and selectedbond
distances and angles are given in Table 3; see also Section 4.
Analytical data for 14. IR (NaCl): n(CO) 2032, 1962
1
cmy1. H NMR (CDCl3): d 7.54–7.19 (m, 10H), 6.10 (s,
2H), 3.83 (d, 11.84 Hz, 1H), 3.02 (d, 11.84 Hz, 1H) ppm.
HRMS: MqyCO calc. 330.0343, obs. 330.0211.
Analytical data for 15. IR (NaCl): n(CO) 1978, 1773
cmy1. 1H NMR (CDCl3): d 7.52–7.24 (m, 20H, Ph), 5.60
(d, 1.9 Hz, 2H), 4.77 (d, 1.9 Hz, 4H) ppm. Anal. Calc. for
C38H26Fe2O4: C, 69.33; H, 3.98. Found: C, 69.58; H, 4.01%.
2.9. Synthesis of 16
Compound 10 (1.0 g, 4.6 mmol) was dissolved in 30 ml
of THF. n-BuLi (2.0 ml, 2.5 M solution) was added to the
THF solution at 08C. After stirring for 1 h at 08C, FeCl2 (0.32
g, 2.5 mmol) was added. The resulting solution was refluxed
for 12 h. After cooling to room temperature, the solvent was
removed, and the residue was extracted with diethyl ether.
The etheral solution was filtered through celite. The filtrate
was concentrated and column chromatographed on silica gel
eluting with hexane. After purification, yellow solids (1.22
g) were obtained quantitatively. 1H NMR (CDCl3): d 7.20
2.12. X-ray structure determination of 12
A single crystal of 12 was a clear yellow prism with natural
faces, but somewhat small, so intensities were mostly low.
Data collection was carried out with a Siemens P4 single-
crystal diffractometer controlled by XSCANS version 2.1
software [22]. Omega scans were used for data collection,
at variable speeds from 10 to 608 per min. Three standard
reflections were measured after every 97 reflections; they

40
Y.K. Kang et al. / Inorganica Chimica Acta 261 (1997) 37–44
Table 1
Table 3
˚
Crystal and refinement data for 8 and 12
Selected bond lengths (A) and bond angles (8) for 8
8
12
Fe–C(1)
Mn–C(6)
Mn–C(03)
2.025(6)
2.251(6)
1.808(9)
Fe–C(3)
Mn–C(8)
C(01)–O(01)
2.040(7)
2.170(8)
1.141(10)
Molecular formula
Formula weight
Crystal system
Space group
C28H18B2F8Mn2O6
743.76
monoclinic
P21/n
7.4732(14)
13.852(2)
14.813(4)
90
C23H13CrMnO6
492.27
monoclinic
P21/c
16.164(3)
10.601(2)
12.424(3)
90
C(1)–Fe–C(2)
41.2(2)
108.4(6)
117.3(6)
178.9(8)
C(1)–Fe–C(4)
68.8(3)
106.4(6)
118.9(8)
90.7(4)
C(1)–C(2)–C(3)
C(7)–C(6)–C(11)
Mn–C(02)–O(02)
C(2)–C(1)–C(5)
C(8)–C(9)–C(10)
C(01)–Mn–C(03)
˚
a (A)
˚
b (A)
˚
c (A)
a (8)
b (8)
101.47(2)
90
1502.7(6)
4
103.64(2)
90
2068.8(7)
4
determined by direct methods and refined initially by use of
programs in the SHELXTL PC version 5.1 package [22],
which were also used for all figures. All 13 hydrogen atoms
appeared in a difference map, and each was introduced in an
ideal position, riding on the atom to which it is bonded; each
was refined with a isotropic temperature factor 20% greater
than that of the ridden atom. All other atoms were refined
with anisotropic thermal parameters. Since chromium and
manganese differ by only one electron, the atoms were inter-
changed as a check of their identification; the discrepancy
values were poorer and the structure became less regular.
Final refinement on F2 was carried out using SHELXL 93
[21]. Crystal data, details of the data collection, and refine-
ment parameters for 12 are listed in Table 1. Final atomic
positional parameters for the non-hydrogen atoms are shown
in Table 4, and selected bond distances and angles are given
in Table 5; see also Section 4.
g (8)
3
˚
V (A )
Z
D
calc (Mg my1
)
1.644
1.581
Crystal size (mm)
l (A)
0.50=0.20=0.10
0.71073 (Mo Ka)
1997
0.24=0.26=0.47
0.71073 (Mo Ka)
3646
˚
Total no. unique
reflections
2u Range (8)
No. parameters
R
4–50
214
0.0762
0.2087
1.082
5–50
280
0.0584
0.1409
0.905
wR2
Goodness of fit
Table 2
Atomic coordinates (=104) and equivalent isotropic displacement param-
2
3
˚
eters (A =10 ) for 8
x
y
z
Ueq
39(1)
Fe
0
5000
5000
Mn
2337(1)
1497(9)
1150(10)
1888(11)
2687(9)
2484(9)
903(9)
y49(9)
1698(1)
3809(5)
3869(5)
4737(6)
5218(6)
4663(5)
3059(5)
2230(5)
1516(6)
1567(6)
2373(6)
3093(5)
1133(7)
615(6)
2209(6)
758(7)
y45(5)
2536(6)
1370(7)
669(4)
3898(1)
4864(4)
5776(4)
6172(5)
5543(5)
4728(5)
4187(5)
4404(5)
3722(7)
2883(6)
2672(5)
3297(4)
3186(6)
4613(7)
4618(6)
2740(6)
5046(6)
5075(6)
7055(7)
7463(5)
6555(5)
7782(6)
6614(7)
48(1)
46(1)
50(2)
60(2)
57(2)
54(2)
45(1)
55(2)
74(2)
73(2)
71(2)
51(2)
78(3)
70(2)
70(2)
136(4)
113(3)
121(3)
74(3)
108(2)
124(3)
155(3)
187(5)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(01)
C(02)
C(03)
O(01)
O(02)
O(03)
B
3. Results and discussion
One of the general synthetic strategies for the synthesis of
cyclopentadienes is the derivatizationofcyclopentenones.To
synthesize the appropriate cyclopentadienyl ligand, we util-
ized the high-yield synthesis of cyclopentenone by the inter-
molecular Pauson–Khand reaction between phenylacetylene
and ethylene in the presence of DMSO as a promoter [23].
After reaction, we could isolate the 1-phenylcyclopentenone
in 70% yield based on (PhC^CH)Co2(CO)6. After reduc-
tion and dehydration, 2 was obtained in 64% yield (Eq. (1)).
y597(11)
y126(12)
816(13)
1363(10)
3703(14)
2625(12)
4353(12)
4577(13)
2827(11)
5610(12)
10191(17)
9294(9)
F(1)
F(2)
F(3)
F(4)
9006(11)
11097(14)
11275(15)
1964(6)
1881(6)
933(6)
Ueq is defined as one third of the trace of the orthogonalized Uij tensor.
(1)
showed a 2.4% decline over the course of data collection, and
corrections were made for their variation. Profile fitting was
used for the reduction of the data and an empirical absorption
correction was applied, based on C-scans. The structure was
When 2 was refluxed with Mn2(CO)10 in xylene, 3 was
obtained in 50% yield (Eq. (2)).

Y.K. Kang et al. / Inorganica Chimica Acta 261 (1997) 37–44
41
Table 4
Mn bimetallic compound [24]. In the same way, treatment
of 3 with (naphthalene)Mn(CO)3 led to a dimanganese
complex (Eq. (3)).
Atomic coordinates (=104) and equivalent isotropic displacement param-
q
2
3
˚
eters (A =10 ) for 12
x
y
z
Ueq
58(1)
Mn(1)
Cr(1)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
2272(1)
2159(1)
5150(1)
5261(1)
5050(5)
6111(5)
6179(6)
5204(8)
4169(6)
4126(5)
4988(4)
4009(4)
4282(5)
5434(4)
5858(5)
6040(5)
5624(6)
6193(9)
7202(9)
7643(6)
7073(6)
4120(5)
3392(4)
5848(7)
6216(6)
6028(6)
6485(5)
6205(6)
6871(5)
4180(6)
3566(5)
5440(8)
5619(7)
3629(1)
3293(3)
3867(3)
4646(4)
4873(4)
4322(4)
3533(4)
2466(3)
1902(3)
1177(4)
1254(3)
2051(3)
608(3)
y2499(1)
y452(5)
y648(5)
y1237(6)
y1689(7)
y1476(7)
y885(6)
179(5)
60(1)
59(2)
62(2)
79(2)
92(2)
82(2)
67(2)
54(1)
60(2)
67(2)
55(1)
57(2)
67(2)
87(2)
105(3)
101(3)
88(2)
76(2)
77(2)
123(2)
107(3)
160(3)
81(2)
133(2)
110(3)
199(4)
85(2)
138(2)
116(3)
182(4)
(3)
However, the dimanganese compound was not stable
enough to characterize completely. While taking H NMR,
1
C(8)
C(9)
641(5)
1135(5)
969(5)
the dimanganese compound decomposed. The carbonyl
stretching frequencies in nitromethane appeared at 2072,
2024 and 1946 cmy1. We could assign the peaks at 2072 and
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
O(1)
C(19)
O(2)
C(20)
O(3)
C(21)
O(4)
C(22)
O(5)
C(23)
O(6)
392(5)
1264(6)
2075(7)
2361(8)
1824(9)
1008(7)
734(7)
y3410(6)
y3949(5)
y3942(7)
y4836(6)
y2847(7)
y3080(7)
2460(7)
2632(7)
2953(7)
3436(6)
3540(8)
4424(6)
2024 cmy1 as arising from (h6-C6H5)Mn(CO)3 and at
q
y65(4)
y668(5)
y626(4)
28(4)
2024 and 1946 cmy1 as arising from (h5-C5H4)Mn(CO)3.
Treatment of 2 with n-BuLi and then with FeCl2 in reflux-
ing THF gave 4 in 92% yield (Eq. (4)).
638(4)
2988(4)
2563(4)
4186(5)
4543(4)
2821(5)
2303(4)
3191(5)
3808(5)
2744(5)
3075(5)
1762(5)
1420(5)
(4)
It was reported [25] that 4 could be prepared in 20% yield
by the reaction of ferrocene with phenyldiazonium salt.Com-
pound 4 was reacted further with 1 equiv. Cr(CO)6. After
workup, we could isolate 5 in 77%. When excess Cr(CO)6
was used, 6 was obtained as a sole product in 83% (Eq. (5)).
Ueq is defined as one third of the trace of the orthogonalized Uij tensor.
Table 5
Selected bond lengths (A) and bond angles (8) for 12
˚
Mn(1)–C(21)
C(1)–C(2)
C(1)–C(7)
Cr(1)–C(4)
C(18)–O(1)
1.763(8)
1.437(7)
1.480(8)
2.204(6)
1.151(7)
C(21)–O(4)
C(1)–C(6)
Cr(1)–C(1)
Cr(1)–C(18)
C(10)–C(12)
1.150(8)
1.375(8)
2.237(6)
1.823(7)
1.458(8)
(5)
C(23)–Mn(1)–C(21)
C(8)–C(7)–C(11)
Mn(1)–C(23)–O(6)
C(1)–Cr(1)–C(4)
92.9(4)
105.9(5)
178.8(8)
79.4(2)
C(9)–C(10)–C(11)
C(8)–C(7)–C(1)
Cr(1)–C(19)–O(2)
C(2)–C(1)–C(6)
106.6(5)
126.1(5)
179.2(7)
118.0(5)
Compound 6 has been previously prepared by an alternate
route [26]. When 5 was reacted with (naphthalene)-
Mn(CO)3q [18], we could isolate the cationic complex 7 in
32% yield (Eq. (6)).
(2)
Several years ago, Rausch and co-workers [16] reported
the preparation of 3 by the reaction of phenylcyclopentadien-
ylthallium and Mn(CO)5Br.
(6)
One of the ways to prepare heteronuclear complexes is to
use free cyclopentadiene or phenyl groups(s). Compound 3
has a phenyl substituent on the cyclopentadienyl ring. Thus
treatment of 3 with Cr(CO)3(NH3)3 gave the diarene Cr–

42
Y.K. Kang et al. / Inorganica Chimica Acta 261 (1997) 37–44
If we used other methods (e.g. Fischer–Hafner method
q
[27] or silver method [28]) to coordinate Mn(CO)3 to
the free phenyl ring, the Cr(CO)3 moiety could not tolerate
q
the reaction conditions. The Mn(CO)3
transfer by
(naphthalene)Mn(CO)3q was so mild that we could prepare
7. Compound 7 contains three different metals, e.g. Cr, Mn
and Fe.
q
Treatment of 4 with excess (naphthalene)Mn(CO)3 in
CH2Cl2 yielded the dicationic Fe–Mn2 complex 8 in 45%
yield (Eq. (7)).
(7)
Fig. 1. Molecular structure of compound 8, with the atomic labeling scheme.
11 has two free phenyl rings which can be coordinated to
other organometallic moieties. Thus, when 11 was reacted
further with Cr(CO)6, 12 and 13 were obtained (Eq. (10)).
Single crystals of 8 suitable for X-ray studies were grown
by the diffusion of diethyl ether into a nitromethane solution
of 8. The molecular geometry and labeling scheme for 8 is
shown in Fig. 1, and selected bond distances and angles are
given in Table 3. The crystal structure of 8 was quite different
from that of 6 [26]. While 6 adopts an eclipsed conformation
with the phenyl groups located in the same direction, 8 adopts
a typical 1,39-orientation which minimizes steric repulsions.
The typical 1,39-orientation was explained on the ground of
minimization of steric repulsion or anefficientpackingwithin
(10)
When 1.3 equiv. Cr(CO)6 was used, 12 and 13 were
obtained in the ratio of 4:1 with a total yield of 75%. Com-
pounds 12 and 13 were easily separated by flash column
chromatography eluting with hexane and ethylacetate (vol./
vol. 20:1). When Cr(CO)3(CH3CN)3 was used as the
Cr(CO)3 source, the yield was rather poor. Single crystals of
12 suitable for X-ray studies were grown by diffusion of
hexane into a methylene chloride solution of 12. The molec-
ular geometry and labeling scheme for 12 are shown in Fig. 2,
and selected bond distances and angles are given in Table 5.
˚
the crystal [29]. The manganese atom is located 1.678 A
below the plane of the phenyl ring. The iron atom is located
˚
1.640 A below the plane of the cyclopentadienyl ring. The
torsion angle between the cyclopentadienyl ring and phenyl
ring is 18.
A mixture of isomers of diphenylcyclopentadiene (10) is
readily prepared from the Pauson–Khand reaction followed
by reduction and dehydration (Eq. (8)) [5].
(8)
When 10 was refluxed with Mn2(CO)10 in xylene, 11 was
obtained in 64% yield (Eq. (9)).
(9)
When we used Mn(CO)3(py)2Br [30,31] as an
Mn(CO)3 source, 11 was obtained in 30% yield. Compound
Fig. 2. Molecular structure of compound 12, with the atomic labeling
scheme.

Y.K. Kang et al. / Inorganica Chimica Acta 261 (1997) 37–44
43
The two metals (Cr and Mn) are on the opposite faces of a
bridging hydrocarbon in anti arrangement as expected due to
steric repulsion. The Mn atom in 12 has the usual piano-stool
coordination characteristic of monocyclopentadienyl com-
plexes [32]. The cyclopentadienyl ring (C7–C11) is planar
contained various ratios of chromium, e.g., Fe/Cr, Fe/Cr2,
Fe/Cr3 and Fe/Cr4 (Eq. (13)).
˚
with a mean deviation of 0.005 A. The Mn atom is located
˚
1.773 A below the plane of the cyclopentadienyl ring. The
phenyl ring (C1–C6) is planar withameandeviationof0.008
˚
˚
A. The Cr atom is located 1.714 A below the plane of the
phenyl ring. The dihedral angle between the planes C1–C6
and C7–C11 is 14.68. The C–O bond distances in the carbonyl
groups are rather insensitive to the metal moieties, and the
(13)
Fortunately, the Fe/Cr4 17 has a very different solubility
from other Fe/Crn (ns1, 2, 3) compounds. While others are
soluble in CH2Cl2, 17 is insoluble in CH2Cl2 and slightly
soluble in acetone. As a result, after washing the reaction
products with CH2Cl2, 17 was obtained in 78% yield. Com-
pound 17 contains five metals in a single molecule.
˚
average C–O distance is 1.146 A.
Treatment of 10 with Fe2(CO)9 in refluxing benzene gave
a cyclopentadiene compound 14 (57%) and a cyclopenta-
dienyl dimeric compound 15 (28%) (Eq. (11)).
We have demonstrated a route for diarene-bridged hetero-
bi- and polymetallic complexes by which chromium, man-
ganese and iron metals can be rationally introduced. We have
crystallographically characterized two of these complexes.
Further research related to the physical properties of poly-
metallic compounds is in progress.
(11)
4. Supplementary material
This reaction is somewhat different from the reaction of
dialkyl-1,3-cyclopentadienes with Fe(CO)5. In the reaction
between dialkyl-1,3-cyclopentadienes with Fe(CO)5, only
substituted cyclopentadienyl dicarbonyl dimers are obtained
[33]. However, Rausch and co-workers [34] reported the
preparation of pentabenzylcyclopentadiene, C5Bz5H. The
reaction between C5Bz5H and Fe(CO)5 in refluxing toluene
led to the formation of [(h5-C5Bz5)Fe(CO)2]2 (8%) and
(h4-C5Bz5H)Fe(CO)3 (25%). Their results look almost the
same as ours, but the yields and ratios are quite different from
ours. In fact, at first we expected only a dimeric compound
with bridging carbonyls. It is anticipated that the exo hydro-
gen in 14 can be easily removed [35] and that 15 will be
easily cleaved by reduction [36]. Thus, we expect that 14
and 15 can be used as versatile precursors for the syntheses
of acyclic compounds.
Tables of complete bond distances and bond angles, an-
isotropic thermal parameters, and hydrogen atom coordinates
for complexes 8 and 12 are available from the authors.
Acknowledgements
We thank the Korea Science and Engineering Foundation
(93-0500-02-01-3), Center for Molecular Catalysis, and Ilju
Foundation for financial support.
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