Nucleophilic substitution reactions of acetylides on substituted tricarbonyl(η6-fluoroarene)chromium and reactions of tricarbonyl[η6-(2-trimethylsilylethynyl)toluene]chromium and tricarbonyl[η6-(p-ethynyl-phenylethynyl)benzene]chromium with dicobalt octacarbonyl

Article abstract of DOI:10.1016/S0277-5387(99)00186-2

Nucleophilic substitution reactions of various acetylides on substituted tricarbonyl(η⁶-fluoroarene)chromiums were pursued. The reaction presumably underwent a more complicated mechanism rather than the direct substitution on the fluorine-bearing carbon. The organometallic compounds (η⁶-C₆H₃R¹R²R ³)Cr(CO)₃ (R¹: CC-C₆H₄CH₃, R²: o-Me, R³: H (5a), R¹: CC-C₆H₄CH₃, R²: o-OMe, R³: H (6a), R¹: CC-C₆H₄CH₃, R²: m-OMe, R³: H (6b), R¹: CCPh, R²: o-Me, R³: o-OMe (8b), R¹: CCPh, R²: m-Me, R³: m-OMe (8c), R¹: CCSiMe₃, R²: o-Me, R³: H (9a), R¹: CC-C₆H₄CCH, R²: H, R³: H (12), R¹: CC-C₆H₄CCH, R²: o-Me, R³: H (13)) as well as the organometallic dimmer [{(η⁶-o-Me-C₆H₄)Cr(CO) ₃(di-ethynyl)] (di-ethynyl: CC-C₆H₄CC (14)) have been synthesized from nucleophilic substitution reactions of tricarbonyl(η⁶-fluoroarene)(chromium) compounds with suitable acetylides. The products have been characterized by spectroscopic means. In addition, (8b) and (8c) were characterized by X-ray diffraction studies. Further reactions of (9a) and (12) with appropriate amount of Co₂(CO)₈ yielded μ-alkyne bridged bimetallic complexes, Co₂(CO)₆{μ-Me₃SiCC-(o-tolueneCr(CO) ₃} (10) and (Co₂(CO)₆)₂{μ-HCC-C₆H ₄-CC-(benzene)Cr(CO)₃)}(15), respectively. Both (10) and (15) were characterized by spectroscopic means as well as single crystal X-ray crystallography. The core of these molecules is quasi-tetrahedron containing a Co₂C₂ unit. A two-dicobalt-fragments coordinated di-enyls complex, (Co₂(CO)₆)₂{μ-HCC-C₆H ₄-CC-H} (17), was synthesized from the reaction of 1,3-diethynylbenzene with Co₂(CO)₈. Crystallographic studies of (17) also show that it exhibits a distorted Co₂C₂ quasi-tetrahedral geometry. Elsevier Science Ltd.

Full text of DOI:10.1016/S0277-5387(99)00186-2

Polyhedron 18 (1999) 2737–2747
www.elsevier.nl/locate/poly
Nucleophilic substitution reactions of acetylides on substituted
tricarbonyl(h6-fluoroarene)chromium and reactions of tricarbonyl[h6-(2-
trimethylsilylethynyl)toluene]chromium and tricarbonyl[h6-( p-ethynyl-
phenylethynyl)benzene]chromium with dicobalt octacarbonyl
a
a
a
a
Fung-E. Honga , , Jenn-Woei Liaw , Bae-Jiunn Chien , Yu-Chang Chang , Chu-Chieh Lin ,
*
Sue-Lein Wangb, Fen-Ling Liaob
aDepartment of Chemistry, National Chung-Hsing University, Taichung 40227, Taiwan, ROC
bDepartment of Chemistry, National Tsing-Hua University, Hsinchu 30043, Taiwan, ROC
Received 5 February 1999; accepted 1 June 1999
Abstract
Nucleophilic substitution reactions of various acetylides on substituted tricarbonyl(h6-fluoroarene)chromiums were pursued. The
reaction presumably underwent a more complicated mechanism rather than the direct substitution on the fluorine-bearing carbon. The
organometallic compounds (h6-C6H3R1R2R3)Cr(CO)3 (R1: C≡C–C6H4CH3, R2: o-Me, R3: H (5a), R1: C≡C–C6H4CH3, R2: o-OMe, R3:
H (6a), R1: C≡C–C6H4CH3, R2: m-OMe, R3: H (6b), R1: C≡CPh, R2: o-Me, R3: o-OMe (8b), R1: C≡CPh, R2: m-Me, R3: m-OMe (8c),
R1: C≡CSiMe3, R2: o-Me, R3: H (9a), R1: C≡C–C6H4C≡CH, R2: H, R3: H (12), R1: C≡C–C6H4C≡CH, R2: o-Me, R3: H (13)) as well as
the organometallic dimmer [h(h6-o-Me-C6H4)Cr(CO)3(di-ethynyl)] (di-ethynyl: C≡C–C6H4C≡C (14)) have been synthesized from
nucleophilic substitution reactions of tricarbonyl(h6-fluoroarene)(chromium) compounds with suitable acetylides. The products have been
characterized by spectroscopic means. In addition, (8b) and (8c) were characterized by X-ray diffraction studies. Further reactions of (9a)
and (12) with appropriate amount of Co2(CO)8 yielded m-alkyne bridged bimetallic complexes, Co2(CO)6hm-Me3SiC≡C–(o-tolueneC-
r(CO)3j (10) and (Co2(CO)6)2hm-HC≡C–C6H4 –C≡C–(benzene)Cr(CO)3)j(15), respectively. Both (10) and (15) were characterized by
spectroscopic means as well as single crystal X-ray crystallography. The core of these molecules is quasi-tetrahedron containing a Co2C2
unit. A two-dicobalt-fragments coordinated di-enyls complex, (Co2(CO)6)2hm-HC≡C–C6H4 –C≡C–Hj (17), was synthesized from the
reaction of 1,3-diethynylbenzene with Co2(CO)8. Crystallographic studies of (17) show that it exhibits a distorted Co2C2 quasi-
tetrahedral geometry.
1999 Elsevier Science Ltd. All rights reserved.
Keywords: Nucleophilic substitution; m-Alkyne bridged bimetallic compounds; Chromium; Cobalt
1. Introduction
via the metal is consistent with our results [3–5]. Accord-
ing to this mechanism, the nucleophilic attack that took
place on a carbon of the phenyl ring does not bear the
leaving group, and is followed by hydrogen migration and
final elimination of the leaving group to achieve aro-
maticity. Recently, nucleophilic aromatic substitution re-
actions via cine or tel-meta mechanism was proposed. The
mechanism involves chromium-hydride and (h4-cyclohex-
adiene) complexes [6–13].
Our previous work has shown that the nucleophilic
substitution of fluoroarene Cr(CO)3 by acetylide under-
went a more complicated reaction mechanism than the
direct substitution on the fluorine-bearing carbon [1,2]. As
shown in Scheme 1, the expected para- product was not
isolated in this reaction condition; instead, two unexpected
products, ortho- and meta-, were obtained.
A proposed mechanism, modified from Pauson and
Brookhart for a related case, involving hydrogen migration
Here, we report more results of the nucleophilic substi-
tution reactions of substituted tricarbonyl(h6-fluoro-
arene)chromium with various acetylides.
The chemistry of alkyne bridge dimetallic compounds
has been examined extensively [14–18]. Among them, the
alkyne-bridged dicobalt complexes, Co2(CO)6(m-RC≡CR),
*Corresponding author. Tel.: 1886-4-285-1180; fax: 1886-4-286-
2547.
E-mail address: fehong@mail.nchu.edu.tw (F.-E. Hong)
0277-5387/99/$ – see front matter
PII: S0277-5387(99)00186-2
1999 Elsevier Science Ltd. All rights reserved.

2738
F.-E. Hong et al. / Polyhedron 18 (1999) 2737–2747
Scheme 1.
were studied extensively [19–21]. Alkyne bridged dicobalt
complexes are believed to be a key step to the productions
in the Pauson–Khand reaction [22–26]. The high yields of
the alkyne bridged dicobalt complexes and the efficient
removal/recovery of the acetylene also makes these com-
plexes acetylene protecting groups [27,28].
The triple bond character of an alkyne is expected to be
reduced while attached to an (arene)Cr(CO)3 group since
the Cr(CO)3 fragment is a strong electron-withdrawing
group [29]. It is, therefore, of interest to us to investigate
the reactivity of the triple bond in Me3SiC≡C–(o-
tolueneCr(CO)3) and m-HC≡C–C6H4 –C≡C–(benzene)C-
r(CO)3 by allowing them to react with Co2(CO)8. Here,
we report the results from these reactions.
anisole]chromium compounds (6a) and (6b) were obtained
from the reaction of tricarbonyl[h6-4-fluroanisole]ch-
romium (1c) with deprotonated 4-tolyl acetylene. The ratio
of (6b)/(6a) is about 3:1 and is in the right region of
Bodner and Todd’s prediction [30].
More complicated results were obtained when tri-substi-
tuted (arene)Cr(CO)3, (7), was reacted with acetylide as
shown in Scheme 4. Tricarbonyl[h6-(3-phenylethynyl-5-
methyl)anisole]chromium (8c) and tricarbonyl[h6-(2-
phenylethynyl-3-methyl)anisole]chromium (8b) as well as
a trace amount of (8a) were obtained from the reaction.
The yields of (8c) and (8b) are 54 and 32%, respectively.
The results are consistent with the prediction from Bodner
and Todd’s rule. It also confirms the fact that the degree of
the activation of substituents are in the order of –OMe.–
Me.–F.
Both (8b) and (8c) were characterized by spectroscopic
means as well as X-ray diffraction studies. (Figs. 1 and 2).
Single crystals of (8c)?1/2H2O, suitable for X-ray struc-
ture determination, were recrystallized from CH2Cl2 at
48C. The water molecules presumably enter the system
during crystallization.
2. Results and discussion
Compound
(5a),
tricarbonyl[h6-(2-(4-methyl-
phenylethynyl))toluene]chromium, and a trace amount of
(5b) were obtained from the reaction of tricarbonyl[h6-4-
flurotoluene]chromium (1b) with deprotonated 4-tolyl
acetylene (Scheme 2). It is consistent with our previous
observations for this type of nucleophilie [1,2].
˚
The bond lengths of C(31)–C(30) is 1.190(10) A for
˚
(8c) (Table 1); it is 1.188(4) A for C(11)–C(12) in (8b)
Similar results were observed for the reaction shown in
(Table 2). Accordingly, they are typical triple bonds. The
dihedral angle between the phenyl ring and the arene is
Scheme 3. Tricarbonyl[h6-(2-(4-methyl-phenylethynyl)-
Scheme 2.
Scheme 3.

F.-E. Hong et al. / Polyhedron 18 (1999) 2737–2747
2739
Scheme 4.
Table 2
Selected bond distances (A) and angles (8) of (8c)
˚
Cr(2)–C(5)
Cr(2)–C(7)
Cr(2)–C(33)
Cr(2)–C(35)
Cr(2)–C(37)
O(6)–C(6)
O(8)–C(8)
C(29)–C(30)
C(31)–C(32)
1.851(10) Cr(2)–C(6)
1.843(9)
1.817(9)
2.225(7)
2.243(8)
2.226(7)
Cr(2)–C(32)
Cr(2)–C(34)
Cr(2)–C(36)
O(5)–C(5)
2.205(7)
2.298(8)
2.250(8)
1.148(12)
1.192(11)
1.341(11)
1.190(10)
1.152(11) O(7)–C(7)
1.381(11) O(8)–C(36)
1.440(9)
C(30)–C(31)
1.432(10)
C(5)–Cr(2)–C(6)
C(6)–Cr(2)–C(7)
Cr(2)–C(6)–O(6)
91.9(4)
88.1(4)
177.7(10)
C(5)–Cr(2)–C(7)
Cr(2)–C(5)–O(5)
Cr(2)–C(7)–O(7)
86.0(4)
180.0(11)
179.6(5)
Fig. 1. ORTEP drawing with the numbering scheme of (8b).
C(29)–C(30)–C(31) 179.2(7)
C(30)–C(31)–C(32) 177.4(7)
about 148 for (8c) and about 1.88 for (8b). These two rings
are almost coplanar and thus might gain better delocaliza-
tion energy among the system.
Tricarbonyl[h6-(2-trimethylsilylethynyl)toluene]chromi-
um (9a) as well as the trace amount of the meta-product,
tricarbonyl[h6 - (3 -trimethylsilylethynyl)toluene]chromium
(9b), were obtained from the reaction of (1b) with
deprotonated trimethylsilylacetylene (Scheme 5). All these
results point to the triple bond character of the nucleophile
is the major factor causing the unusual substitution mecha-
nism.
Fig. 2. ORTEP drawing with the numbering scheme of (8c). Hydrogen
Results from Scheme 5 are summarized in Table 3.
With the presence of the strong electron-withdrawing
Cr(CO)3 fragment in the (arene)Cr(CO)3, one might
expect a diminishing of the triple bond character. How-
ever, an alkyne bridged dicobalt complex, Co2(CO)6hm-
Me3SiC≡C–(o-tolueneCr(CO)3j (10) was obtained from
the reaction of (9a) with Co2(CO)8 even under room
temperature (Scheme 6). It indicates that the triple bond of
(9a) is still active enough to bond to the dicobalt center, in
spite of the presence of the strongly electron-withdrawing
Cr(CO)3 fragment.
atoms are omitted for clarity.
Table 1
˚
Selected bond distances (A) and angles (8) of (8b)
Cr(1)–C(1)
Cr(1)–C(3)
Cr(1)–C(14)
Cr(1)–C(16)
Cr(1)–C(18)
O(2)–C(2)
O(4)–C(4)
C(10)–C(11)
C(12)–C(13)
1.823(4) Cr(1)–C(2)
1.840(4) Cr(1)–C(13)
2.269(3) Cr(1)–C(15)
2.175(4) Cr(1)–C(17)
2.223(3) O(1)–C(1)
1.161(4) O(3)–C(3)
1.430(4) O(4)–C(14)
1.435(4) C(11)–C(12)
1.434(4)
1.833(4)
2.245(3)
2.228(3)
2.213(4)
1.161(5)
1.150(5)
1.351(4)
1.188(4)
Complex (10) was characterized by mass, infrared, 1H,
13C NMR spectra as well as X-ray diffraction studies. The
core of this molecule is a quasi-tetrahedral Co2C2 unit
consistent with most of these types of molecule. Two
substituents, SiMe3 and o-tolueneCr(CO)3 bend away
from the metal center (Fig. 3). The bond length of the
C(1)–Cr(1)–C(2)
C(2)–Cr(1)–C(3)
Cr(1)–C(1)–O(1)
Cr(1)–C(3)–O(3)
86.6(1)
88.8(2)
177.4(3)
176.3(4)
C(1)–Cr(1)–C(3)
C(4)–O(4)–C(14)
Cr(1)–C(2)–O(2)
91.0(2)
118.0(2)
177.9(3)
C(10)–C(11)–C(12) 177.0(3)
˚
bridged acetylene in (10) is 1.344 A which is slightly
C(11)–C(12)–C(13) 174.8(3)
longer than that of Co2(CO)5(PPh3)hm-PhC≡CHj,

2740
F.-E. Hong et al. / Polyhedron 18 (1999) 2737–2747
Scheme 5.
Table 3
Nucleophilic substitution reactions of tricarbonyl(h6-fluoroarene)ch-
romium with acetylides
Entry
Reactant
Nucleophile
Product
Yield (%)
1
2
3
4
5
6
7
8
1b
1c
1c
7
p-Methylbenzylacetylide
p-Methylbenzylacetylide
p-Methylbenzylacetylide
Phenylacetylide
5a
6a
6b
8b
8c
9a
12
13
77
18
59
32
54
30
37
47
7
Phenylacetylide
1b
1a
1b
Trimethylsilylacetylide
p-Ethynl-phenylacetylide
p-Ethynl-phenylacetylide
Co2(CO)4(PPh3)2hm-PhC≡CHj (Table 4). The bond
˚
lengths of the latter two compounds are 1.329 and 1.325 A,
respectively [31]. The elongation of the carbon–carbon
bond in the bridged acetylene in (10) might due to a better
backbonding effect caused by the strong electron-with-
drawing Cr(CO)3 fragment. It is also evidenced by the fact
that larger bend away angles, 153.8 and 146.88 for
C;C–SiMe3 and C;C–areneCr(CO)3, respectively, are
observed in (10). In addition, the bond distances of
acetylene to dicobalt center in (10) is also longer than most
of the related compounds. Co2(CO)6hm-Me3SiC≡C–(o-
C6H5CH3)j (11) was observed as the Cr(CO)3 decomplex-
ed product from (10). The absence of the diagnostic
Fig. 3. ORTEP drawing with the numbering scheme of (10). Hydrogen
atoms are omitted for clarity.
another example of this type of work. It has been prepared
by successive reactions as shown in Scheme 7. First,
tricarbonyl[h6-( p-ethynyl-phenylethynyl)benzene]ch-
romium (12) was obtained from the nucleophilic substitu-
tion of tricarbonyl[h6-fluorobenzene]chromium (1b) with
deprotonated p-diethynylbenzene. Then, (o-CH3-h6-
C6H4Cr(CO)3)–C;CC6H4C;C–(o-CH3-h6-
C6H4Cr(CO)3) (14) was obtained from the further nu-
cleophilic substitution of (1b) with deprotonated (13).
There are two triple bonds available for the coordination
of the dicobalt fragment Co2(CO)6 in (12). One might
expect that the reduction in reactivity of the triple bond
adjacent to the areneCr(CO)3 moiety is due to a strongly
1
(arene)Cr(CO)3 peaks in H NMR indicates the loss of the
Cr(CO)3 fragment.
Conjugated oligomers have attracted much attention due
to their potential in material science [32,33]. 1,4-Diethy-
nylbenzene, –C;CC6H4C;C–, has been frequently in-
volved in organic and homometallic polymers as a building
block unit. Many attempts have been pursued in order to
incorporate organometallic fragments to both sides of this
unit [34]. The synthesis of (o-CH3-h6-C6H4Cr(CO)3)–C;
CC6H4C;C–(o-CH3-h6-C6H4Cr(CO)3) (14) provides
Scheme 6.

F.-E. Hong et al. / Polyhedron 18 (1999) 2737–2747
2741
Table 4
Selected bond distances (A) and angles (8) of (10)
C≡C–(benzene)Cr(CO)3)j (15), was obtained in a reason-
able yield. The results seem to indicate that two triple bond
characters of di-enyls are similar. The Cr(CO)3 metal
fragment decomplexed product, (Co2(CO)6)2hm-HC≡C–
C6H4 –C≡CPh)j(16), was observed in the above reaction.
This repeatedly observed phenomenon indicates that the
bonding between the arene and Cr(CO)3 fragment is not as
strong as that of Co2(CO)6 fragment to an alkyne.
(Co2(CO)6)2hm-HC≡C–C6H4 –C≡C–(benzene)C-
˚
Co(1)–Co(2)
Co(1)–C(11)
Co(1)–C(12)
Co(1)–C(16)
Co(1)–C(18)
Co(2)–C(20)
C(4)–C(11)
Cr–C(4)
2.477(1) C(11)–C(12)
1.956(3) Co(2)–C(11)
1.996(3) Co(2)–C(12)
1.822(3) Co(1)–C(17)
1.815(4) Co(2)–C(19)
1.782(4) Co(2)–C(21)
1.462(4) Si–C(12)
2.234(3) Cr–C(5)
2.222(4) Cr–C(7)
2.220(3) Cr–C(9)
1.495(4)
1.344(4)
1.990(2)
1.997(2)
1.792(3)
1.819(3)
1.814(3)
1.866(3)
2.239(3)
2.204(4)
2.189(3)
r(CO)3)j (15) was characterized by mass, infrared, 1H, 13
C
Cr–C(6)
Cr–C(8)
C(5)–C(10)
NMR spectra as well as X-ray diffraction studies. The
basic Co2C2 core structure of (15) is not much different
from (10). Substituents of the coordinated acetylenes all
bend away from the metal center (Fig. 4). The bond length
of the two bridged acetylene, C(22)–C(23) and C(30)–
Co(2)–Co(1)–C(11)
Co(1)–Co(2)–C(11)
Co(1)–C(11)–Co(2)
Co(1)–C(11)–C(12)
Co(2)–C(11)–C(12)
C(11)–Co(1)–C(12)
Co(1)–C(12)–Si
51.7(1)
50.5(1)
77.7(1)
71.7(2)
70.6(2)
39.7(1)
127.6(2)
135.5(2)
Co(2)–Co(1)–C(12)
51.7(1)
51.6(1)
76.7(1)
68.5(2)
70.0(1)
39.4(1)
129.9(1)
125.9(2)
Co(1)–Co(2)–C(12)
Co(1)–C(12)–Co(2)
Co(1)–C(12)–C(11)
Co(2)–C(12)–C(11)
C(11)–Co(2)–C(12)
Co(2)–C(12)–Si
˚
C(31) are 1.354 and 1.328 A, respectively, and these are
typical double bonds (Table 5). The bond length of C22–
C23 is longer than that of C30–C31. This is probably due
to a better backbonding effect caused by the electron-
withdrawing group, arene Cr(CO)3. It is slightly longer
than that of Co2(CO)5(PPh3)hm-PhC≡CHj, Co2(CO)4
Co(1)–C(11)–C(4)
Co(2)–C(11)–C(4)
electron-withdrawing group, Cr(CO)3 fragment. The re-
action of (12) with Co2(CO)8 was carried out at room
temperature (Scheme 8). A two-dicobalt-fragment coordi-
nated di-enyl complex, (Co2(CO)6)2hm-HC≡C–C6H4 –
˚
(PPh3)2hm-PhC≡CHj. They are 1.329 and 1.325 A, respec-
tively.
The reaction between 1,3-diethynylbenzene with
Scheme 7.
Scheme 8.

2742
F.-E. Hong et al. / Polyhedron 18 (1999) 2737–2747
Co2(CO)8 was carried out (Scheme 9). It does not take
place until 558C, presumably, due to the steric hindrance of
two neighboring Co(CO)3 fragments [35]. two-
A
Co2(CO)6 coordinated di-enyl complex, (Co2(CO)6)2hm-
HC≡C–C6H4 –C≡C–Hj (17), was obtained. Complex (17)
was characterized by spectroscopic means as well as X-ray
diffraction studies. Two dicobalt fragments lie on the same
side of the molecule and bend away from each other. The
bond lengths of C6–C7 and C30–C26 are 1.318 and 1.320
˚
A, respectively. They are shorter than that of the corre-
sponding bond lengths of (15). Obviously, the electron-
withdrawing Cr(CO)3 fragment in (15) plays a significant
role on this. By examining the crystal structures of (10),
(15) and (17), we observed that the Co–C bond lengths are
in the order of Co–CH,Co–CPh,Co–CTMS (Fig. 5, Table
6).
The orientation of the Cr(CO)3 unit in (arene)Cr(CO)3
complexes is the subject of extensive study. An anti-
eclipsed form is observed for (arene)Cr(CO)3 with an
electron withdrawing substituent. On the other hand, a
syn-eclipsed form is observed for (arene)Cr(CO)3 with an
electron donating substituent [36,37]. The orientation of
Cr(CO)3 in (arene)Cr(CO)3 is about syn-eclipsed, with
respect to the –OMe group, for (8b) and (8c). It seems that
the strong p electron-donating substituent, –OMe group, is
the major factor dominated by the orientation of Cr(CO)3
in (8b) and (8c). The phenylacetylide substituent as well as
the –Me group does not play a significant role here (Fig.
6).
Fig. 4. ORTEP drawing with the numbering scheme of (15). Hydrogen
atoms are omitted for clarity.
Table 5
˚
Selected bond distances (A) and angles (8) of (15)
Co(1)–Co(2)
Co(1)–C(22)
Co(2)–C(7)
Co(2)–C(23)
Co(3)–C(10)
Co(3)–C(31)
Co(4)–C(30)
Cr(1)–C(1)
O(1)–C(1)
2.472(1) Co(1)–C(4)
1.954(2) Co(1)–C(23)
1.825(3) Co(2)–C(22)
1.965(3) Co(3)–Co(4)
1.801(4) Co(3)–C(30)
1.955(3) Co(4)–C(13)
1.987(3) Co(4)–C(31)
1.861(4) Cr(1)–C(16)
1.139(5) C(21)–C(22)
1.354(3) C(23)–C(24)
1.460(4) C(30)–C(31)
1.827(3)
1.977(2)
1.990(3)
2.484(1)
1.958(3)
1.810(4)
1.961(3)
2.219(3)
1.461(4)
1.467(3)
1.328(4)
An anti-eclipsed form, with respect to the
C(22)–C(23)
C(27)–C(30)
Co(2)–Co(1)–C(22)
Co(1)–Co(2)–C(22)
C(22)–Co(2)–C(23)
Co(2)–C(22)–C(23)
Co(2)–C(23)–C(22)
Co(4)–Co(3)–C(30)
C(30)–Co(3)–C(31)
Cr(1)–C(2)–O(2)
51.8(1)
50.6(1)
40.0(1)
69.0(2)
71.0(2)
51.5(1)
39.7(1)
179.3(3)
176.9(3)
105.0(2)
178.3(3)
Co(2)–Co(1)–C(23)
50.9(1)
51.4(1)
77.6(1)
77.7(1)
40.3(1)
50.7(1)
177.8(3)
179.6(4)
98.9(2)
177.2(3)
177.4(3)
Co(1)–Co(2)–C(23)
Co(1)–C(22)–Co(2)
Co(1)–C(23)–Co(2)
C(22)–Co(1)–C(23)
Co(4)–Co(3)–C(31)
Cr(1)–C(1)–O(1)
Cr(1)–C(3)–O(3)
C(5)–Co(1)–C(6)
Co(1)–C(4)–O(4)
Co(2)–C(8)–O(8)
Co(1)–C(5)–O(5)
C(7)–Co(2)–C(8)
Co(1)–C(6)–O(6)
Co(3)–C(10)–O(10) 176.5(3)
Co(4)–C(14)–O(14) 178.6(4)
C(16)–C(21)–C(22) 121.8(2)
C(20)–C(21)–C(22) 120.6(2)
C(22)–C(23)–C(24) 144.9(3)
C(27)–C(30)–C(31) 143.6(3)
Co(3)–C(12)–O(12) 178.2(4)
Cr(1)–C(16)–C(17) 72.1(2)
C(23)–C(24)–C(25) 120.6(2)
C(21)–C(22)–C(23) 144.6(2)
C(23)–C(24)–C(29) 121.9(2)
Fig. 5. ORTEP drawing with the numbering scheme of (17).
Scheme 9.

F.-E. Hong et al. / Polyhedron 18 (1999) 2737–2747
2743
Table 6
Selected bond distances (A) and angles (8) of (17)
In summary, acetylides are quite unique nucleophiles
that cause the nucleophilic substitution reactions on
(fluoroarene)Cr(CO)3 and undergo unconventional mecha-
nism. In addition, we were able to synthesize m-alkyne
bridged bimetallic compounds, (10) and (15). It is obvious
that the distinct spectroscopic and structural changes of
(10) and (15) are partially due to the strong electron-
withdrawing ability of the Cr(CO)3 fragment.
˚
Co(l)–Co(2)
Co(l)–C(13)
Co(2)–C(4)
Co(2)–C(14)
Co(3)–C(7)
Co(3)–C(22)
Co(4)–C(21)
O(1)–C(1)
2.469(1) Co(l)–C(1)
1.950(3) Co(l)–C(14)
1.820(4) Co(2)–C(13)
1.953(3) Co(3)–Co(4)
1.807(4) Co(3)–C(21)
1.958(3) Co(4)–C(10)
1.972(3) Co(4)–C(22)
1.136(5) C(13)–C(14)
1.466(4)
1.807(4)
1.972(3)
1.937(3)
2.471(1)
1.952(3)
1.817(4)
1.945(3)
1.317(5)
C(14)–C(15)
Co(2)–Co(1)–C(1)
Co(2)–Co(1)–C(13)
C(13)–Co(1)–C(14)
C(4)–Co(2)–C(13)
C(13)–Co(2)–C(14)
Co(4)–Co(3)–C(22)
Co(3)–Co(4)–C(21)
Co(1)–C(13)–Co(2)
Co(2)–C(13)–C(14)
Co(1)–C(14)–C(13)
Co(1)–C(14)–C(15) 128.8(2)
C(13)–C(14)–C(15) 144.7(3)
Co(3)–C(21)–C(19) 136.4(2)
Co(3)–C(21)–C(22)
C(19)–C(21)–C(22) 142.2(3)
Co(4)–C(22)–C(21) 71.4(2)
100.5(1)
C(1)–Co(1)–C(2)
101.6(2)
3. Experimental
50.3(1)
39.2(1)
101.9(2)
39.6(1)
50.5(1)
50.6(1)
78.9(1)
70.9(2)
69.5(2)
Co(2)–Co(1)–C(14)
Co(1)–Co(2)–C(13)
Co(1)–Co(2)–C(14)
Co(4)–Co(3)–C(21)
C(21)–Co(3)–C(22)
Co(1)–C(1)–O(1)
Co(1)–C(13)–C(14)
Co(1)–C(14)–Co(2)
Co(2)–C(14)–C(13)
Co(2)–C(14)–C(15) 137.5(2)
Co(3)–C(21)–Co(4) 78.1(1)
Co(4)–C(21)–C(19) 132.1(2)
Co(4)–C(21)–C(22)
Co(3)–C(22)–C(21)
50.7(1)
50.8(1)
51.4(1)
51.3(1)
39.4(1)
174.4(4)
71.3(2)
77.9(1)
69.5(2)
All operations were performed in a nitrogen-flushed
glove box or in a vacuum system. Freshly distilled solvents
were used. All processes of separation of the products were
performed by centrifugal thin-layer chromatography (TLC,
Chromatotron, Harrison model 8924). H and 13C NMR
1
spectra were recorded (Varian-300 spectrometer) at 300
and 75.46 MHz, respectively; chemical shifts are reported
in ppm relative to internal TMS. IR spectra of solution in
CHCl3 were recorded on a Hitachi 270-30 spectrometer.
Mass spectra were recorded on JOEL JMS-SX/SX 102A
GC/MS/MS spectrometer. Elementary analysis were re-
corded on Heraeus CHN-O-S-Rapid.
70.5(2)
69.2(2)
70.0(2)
3.1. General procedure for preparations of (5a), (6a),
(6b), (8a), (8b), (8c), (9a), (12), (13) [1,2]
Into a 50-cm3 flask was placed 4-ethynyltoluene,
CH3C6H4C≡CH, (0.12 cm3, 0.95 mmol) and 20 cm3 of
anhydrous tetrahydrofuran. The solution was cooled to
2948C (acetone–N2(l) bath). Next, n-BuLi (1.6 M, 0.4 ml,
0.64 mmol) was added drop by drop to the cold reaction
flask. The deprotonation process was carried out at that
temperature for 1.2 h and then added HMPA (0.56 cm3,
3.2 mmol); 30 min later, a solution of tricarbonyl(h6-4-
fluorotoluene)chromium (1b) (0.13 g, 0.53 mmol) in 1.0
cm3 of anhydrous THF was added slowly to the cold
reaction mixture. The reaction was well stirred at 2948C
for another 3 h and gently warmed to room temperature
during the next 16 h.
Subsequently, the resulting yellow solution was filtered
through a small amount of silica gel. The filtrate was
evaporated under reduced pressure to yield the crude
product. Purification with centrifugal thin-layer chromatog-
raphy (eluent: hexane), a yellow band of tricarbonyl[h6-(2-
(4-methyl-phenylethynyl))toluene]chromium (5a) and trace
amount of (5b) were obtained. Complex (5a) was isolated
(0.14 g, 0.41 mmol). The yield of (5a) is 77.4%.
Fig. 6. Top view of (arene)Cr(CO)3 of (8b) and (8c).
Co2(CO)6(alkyne) fragment, was observed for both (10)
and (15). It might be due to its bulky substituent, alkyne
bridged dicobalt fragment [38,39] (Fig. 7).
3.1.1. Characterization of (5a)
1H NMR (CDCl3): d 2.40 (s, 3H, Me), 2.38 (s, 3H, Me),
5.69 (d, J56.2 Hz, 1H,), 5.36 (d, J56.2 Hz, 1H), 5.22 (m,
Fig. 7. Top view of (arene)Cr(CO)3 of (10) and (15).
2H), 7.17 (d, J58.2 Hz, 2H), 7.41 (d, J58.2 Hz, 2H). 13
C
NMR (CDCl3): d 20.02 (1C, Me), 21.47 (1C, Me), 83.68,

2744
F.-E. Hong et al. / Polyhedron 18 (1999) 2737–2747
89.11, 90.50, 92.11, 92.52, 96.47, 110.52, 118.93, 129.21,
131.74, 139.34 (12C, Ph), 232.76 (3C, 3CO). IR(CH2Cl2):
n(CO) 1904, 1976 cm21. MS m/z 342 (M1).
areneCr(CO)3), 232.36 (3C,Cr(CO)3). IR(CH2Cl2): n(CO)
1968 (s), 1896 (s) cm21. MS m/z 432 (M1).
3.2. General procedure for preparations of (10), (15),
(17)
3.1.2. Characterization of (6a)
1H NMR (CDCl3): d 2.37 (s, 3H, Me), 3.85 (s, 3H,
OMe), 4.94 (dd, J56.2, 6.2 Hz, 1H), 5.12 (d, J56.6 Hz,
1H), 5.52 (m, 1H), 5.85 (dd, J51.4, 6.3 Hz, 1H), 7.15 (d,
J58.4 Hz, 2H), 7.43 (d, J58.4 Hz, 2H). 13C NMR
(CDCl3): d 21.50 (1C, Me), 56.24 (1C, OMe), 73.55,
80.47, 81.46, 84.65, 92.57, 98.18, 119.29, 129.12, 131.87,
139.09, 142.77 (12C, Ph), 232.59 (3C, 3CO). IR(CH2Cl2):
n(CO) 1905, 1977 cm21. MS m/z 358 (M1).
Into a 50-cm3 flask was placed dicobalt octacarbonyl,
Co2(CO)8, (0.2 g, 0.585 mmol) and tricarbonyl[h6-(2-
trimethylsilylethynyl)toluene] chromium (9) (0.12 g, 0.370
mmol) with 20 cm3 of toluene. The solution was stirred
under room temperature during the next 16 h.
Subsequently, the resulting dark purple solution was
filtered through a small amount of silica gel. The filtrate
was evaporated under reduced pressure to yield the crude
product. Purification with centrifugal thin-layer chromatog-
raphy (eluent: hexane), a purple band of Co2(CO)6hm-
Me3SiC≡C–(o-tolueneCr(CO)3)j (10) was obtained. (10)
was isolated (0.08 g, 0.131 mmol). The yield of (10) is
35.4%.
3.1.3. Characterization of (6b)
1H NMR (CDCl3): d 2.37 (s, 3H, Me), 3.74 (s, 3H,
OMe), 5.07 (m, 2H), 5.30 (s, 1H), 5.56 (dd, J56.6, 6.6
Hz, 1H), 7.16 (d, J57.8 Hz, 2H), 7.42 (d, J57.8 Hz, 2H).
13C NMR (CDCl3): d 21.52 (1C, Me), 55.66 (1C, OMe),
76.71, 79.99, 84.61, 88.05, 90.82, 93.08, 93.70, 118.60,
129.25, 131.92, 139.61, 142.35 (12C, Ph), 233.02 (3C,
3CO). IR(CH2Cl2): n(CO) 1902, 1976 cm21. MS m/z 358
(M1).
Similar procedures were taken. The yield of (15) is
48.3%. The reaction temperature was maintained at 558C
in the synthesis of (17). The yield of (17) is 58.7%.
3.2.1. Characterization of (10)
1H NMR(CDCl3): d 0.47 (s, 9H, SiMe3), 2.44 (s, 3H,
Me), 5.12 (m, 2H, areneCr(CO)3), 5.60 (t, 1H,
areneCr(CO)3), 5.92 (d, J56.2, 1H, areneCr(CO)3). 13C
NMR(CDCl3): d 1.83 (s, 3C, SiMe3), 21.12 (s, 1C, Me),
82.99, 100.27 (2C, –C=C–) 87.88, 90.44, 95.15, 98.85
(4C, areneCr(CO)3), 105.25, 110.35 (2C, ipso of
areneCr(CO)3), 199.24 (6C, Co2(CO)6), 232.49 (3C,
Cr(CO)3). IR(CH2Cl2): n(CO) 2091 (m), 2056 (s), 2027
3.1.4. Characterization of (8b)
1H NMR(CDCl3): d 2.49 (s, 3H, Me), 3.85 (s, 3H,
OMe), 4.88 (d, J56 Hz, 1H, areneCr(CO)3), 5.03 (d, J57
Hz, 1H, areneCr(CO)3), 5.53 (d, J57 Hz, 1H,
areneCr(CO)3), 7.25–7.6 (m, 5H, arene). 13C
NMR(CDCl3): d 20.47 (1C, Me), 56.30 (1C, OMe), 81.28,
95.53 (2C, –C=C–), 81.72, 112.52, 122.64 (3C, ipso of
areneCr(CO)3), 71.70, 86.34, 92.29 (3C, areneCr(CO)3),
128.36, 128.76, 131.87 (5C, arene), 143.27 (1C, ipso of
arene), 232.83 (3C, Cr(CO)3). IR(CH2Cl2): n(CO) 1964 (s),
1886 (s) cm21. MS m/z 358 (M1). Anal.: Calcd.: C,
63.69; H, 3.94. Found: C, 62.27; H, 4.29.
(m), 1965 (m), 1894 (m) cm21. MS m/z 610 (M1). Anal.:
Calcd.: C, 41.33; H, 2.64. Found: C, 41.48; H, 2.87.
3.2.2. Characterization of (11)
1H NMR(CDCl3): d 0.42 (s, 9H, SiMe3), 2.47 (s, 3H,
–Me), 7.16–7.24 (m, 3H, Ph), 7.59–7.63 (t, 1H, Ph). 13
C
3.1.5. Characterization of (8c)
NMR(CDCl3): d 1.62 (3C, SiMe3), 21.91 (1C, –Me),
82.78, 103.94 (2C, –C=C–), 117.23 (1C, ipso of arene),
126.49, 127.89, 130.51, 133.00 (4C, arene), 136.18 (1C,
ipso of arene), 200.32 (6C, Co2(CO)6). IR(CH2Cl2): n(CO)
2086 (m), 2050 (s), 2020 (s) cm21. MS m/z 474 (M1).
1H NMR(CDCl3): d 2.29 (s, 3H, Me), 3.74 (s, 3H,
OMe), 4.99, 5.20 (3H, areneCr(CO)3), 7.25–7.6 (m, 5H,
arene). 13C NMR(CDCl3): d 20.86 (1C, Me), 55.66 (1C,
OMe), 79.05, 89.41 (2C, –C=C–), 92.54, 121.69, 124.99
(3C, ipso of areneCr(CO)3), 109.26, 113.31, 115.90 (3C,
areneCr(CO)3), 128.43, 129.17, 131.98 (5C, arene), 142.68
(1C, ipso of arene), 233.25 (3C, Cr(CO)3). IR(CH2Cl2):
n(CO) 1967 (s), 1890 (s) cm21. MS m/z 358 (M1).
3.2.3. Characterization of (12)
1H NMR (CDCl3): d 3.19 (s, 1H, –C≡CH), 5.28 (t, 1H,
J56.8 Hz, areneCr(CO)3), 5.36 (t, 2H, J56.4 Hz,
areneCr(CO)3), 5.53 (d, J56.4 Hz, areneCr(CO)3), 7.46
(dd, 4H, –Ph–) 13C NMR (CDCl3): d 79.40 (s, 1C, CH),
83.02 (1C, –C≡CH), 87.07, 89.00 (2C, –C≡C–), 89.83
(1C, ipso of areneCr(CO)3), 90.69, 91.41, 94.76 (5C,
areneCr(CO)3), 131.79, 132.10 (4C, –Ph–), 122.18,
122.75 (2C, ipso of Ph), 232.00 (3C, Cr(CO)3). IR
(CH2Cl2): n(CO) 51974 (s), 1903 (s) cm21. MS m/z 338
(M1).
3.1.6. Characterization of (9a)
1H NMR(CDCl3): d 5.58 (d, J56.2 Hz, 1H), 5.32 (dd,
J55.6, 5.6 Hz, 1H), 5.16 (m, 2H), 2.31 (s, 3H, Me), 0.24
(s, 9H, SiMe3). 13C NMR(CDCl3): d 20.20 (s, 3C,
SiMe3), 19.95 (s, 1C, Me), 88.92, 91.90, 92.34, 96.47 (4C,
areneCr(CO)3), 89.64, 98.36 (2C, –C=CSiMe3), 99.65
(1C, ipso of areneCr(CO)3), 110.63 (1C, ipso of

F.-E. Hong et al. / Polyhedron 18 (1999) 2737–2747
2745
3.2.4. Characterization of (13)
1H NMR (CDCl3):
2.40 (s, 3H, –CH3 of
0.92 mmol) in 2.0 cm3 of anhydrous THF was added
slowly to the cold reaction mixture. The reaction was well
stirred and gently warmed to room temperature during the
next 16 h.
Subsequently, the resulting yellow solution was filtered
through a small amount of silica gel. The filtrate was
evaporated under reduced pressure to yield the crude
product. Purification with centrifugal thin-layer chromatog-
raphy (eluent: hexane), a yellow band of (14) was isolated.
The yield of (14) is 37.2%.
d
areneCr(CO)3), 3.20 (s, 1H, –C≡CH), 5.20 (t, 1H,
areneCr(CO)3), 5.24 (d, J56.0 Hz, 1H, areneCr(CO)3),
5.39 (t, 1H, areneCr(CO)3), 5.69 (d, J56.4 Hz, 1H,
areneCr(CO)3), 7.47 (dd, 4H, –Ph–). 13C NMR (CDCl3): d
20.13 (s, 1C, CH3 of areneCr(CO)3), 79.33 (s, 1C, ≡CH),
83.05 (1C, –C≡CH), 86.31, 89.21 (2C, –C≡C–), 91.49
(1C, ipso of areneCr(CO)3), 88.80, 91.80, 92.62, 96.45
(4C, areneCr(CO)3), 110.48 (1C, ipso of areneCr(CO)3,
–CH3), 122.43, 122.65 (2C, ipso of Ph), 131.66, 132.08
(4H, –Ph–), 232.27 (3C, Cr(CO)3). IR (CH2Cl2): n(CO)
5
1970 (s), 1896 (s) cm21. MS m/z 352 (M1).
3.3.1. Characterization of (14)
1H NMR (CDCl3): d 2.41 (s, 6H, two CH3 of
areneCr(CO)3), 5.20 (t, J56.2 Hz, 2H, areneCr(CO)3),
5.25 (d, J56.2 Hz, 2H, areneCr(CO)3), 5.40 (t, 2H,
J56.2 Hz, areneCr(CO)3), 5.70 (d, J56.4 Hz, 2H,
areneCr(CO)3), 7.49 (dd, 4H, –Ph–). 13C NMR (CDCl3): d
20.16 (s, 2C, two CH3 of each areneCr(CO)3), 86.67,
89.22 (4C, –C≡C–), 91.57 (2C, ipso of each
areneCr(CO)3), 88.80, 91.81, 92.66, 96.48 (8C, two
areneCr(CO)3), 110.52 (2C, ipso of each areneCr(CO)3,
–CH3), 122.57 (s, 2C, ipso of Ph), 131.49, 131.77 (4C,
–Ph–), 232.28 (6C, Cr(CO)3). IR (CH2Cl2): n(CO) 51970
(s), 1896 (s) cm21. MS m/z 578 (M1).
3.3. Preparation of (14)
Into a 100-cm3 flask was placed (13), (390 mg, 1.11
mmol) and 5 cm3 of anhydrous tetrahydrofuran. The
solution was cooled to 2408C (acetonitrile–N2(l) bath).
Next, n-BuLi (0.55 ml, 1.38 mmol) was added drop by
drop to the cold reaction flask. The deprotonation process
was carried out at that temperature for 1.0 h and then
added HMPA (0.8 cm3, 4.6 mmol); 30 min later, a solution
of tricarbonyl(h6-4-fluorotoluene)chromium (1b) (228 mg,
Table 7
Crystal data of (8b), (8c), (10), (15) and (17)
1
]
Formula
C19H14CrO4
358.3
Orthorhombic
Pca21
9.0616(3)
12.7028(4)
14.6355(4)
C19H14CrO4?2 H2O
367.3
Triclinic
¯
P1
9.0463(1)
9.2980(1)
21.1307(3)
85.074(1)
85.877(1)
86.931(1)
1764.2(6)
2
C21H16Co2CrO9Si
610.3
Triclinic
¯
P1
8.376(2)
8.699(2)
17.616(2)
87.70(2)
80.31(2)
74.14(2)
1216.9(4)
2
C13H10Co4CrO15H16
910.1
Triclinic
¯
P1
7.5655(1)
14.5406(1)
15.8095(2)
95.024(1)
97.055(0)
91.599(1)
1718.0(6)
2
C22H6Co4O12
698.0
Monoclinic
P21 /n
9.2780(2)
12.6522(1)
22.5876(4)
Formula weight
Crystal system
Space group
˚
a (A)
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
100.178(1)
3
˚
V (A )
1684.7(5)
4
1.413
0.71073
0.697
2609.8(7)
4
1.776
0.71073
2.558
Z
Dc (g cm23
)
1.383
0.71073
0.670
1.665
0.71073
1.882
1.759
0.71073
2.267
˚
l (Mo Ka), A
m (mm21
)
Range (8)
Scan speed
Scan range
No. of reflections
collected
No. of independent
reflections
No. observed reflections
No. of refined parameters
Rf for significant
reflectionsa
2.5–55.9
10.00 s/frame
0.308/frame
9603
(8251$3.0s(I))
3442
(Rint 53.29%)
(2531$3.0s(I))
218
2.5–55.8
10.00 s/frame
0.308/frame
17 269
(12398$3.0s(I))
7541
(Rint 53.69%)
(4181$3.0s(I))
442
4.0–48.0
Variable
0.408/frame
4063
2.5–56.9
10.00 s/frame
0.308/frame
16 208
(13338$3.0s(I))
7355
(Rint 53.56%)
(5140$3.0s(I))
461
2.5–55.8
10.00 s/frame
0.308/frame
14 581
(11969$3.0s(I))
5550
(Rint 54.11%)
(3411$3.0s(I))
344
3774
(Rint 51.01%)
(3284$4.0s(F))
307
0.0315
0.0715
0.0281
0.0296
0.0294
Rw for significant
0.0328
1.34
0.0903
1.24
0.0447
1.16
0.0315
1.01
0.0309
1.19
reflectionsb
GoFc
a Rf 5 [o(Fo 2 Fc)/o Fo].
b Rw 5 o w1 / 2(Fo 2 Fc)/o w1 / 2Fo.
c GoF 5 [o w(Fo 2 Fc)2 /(Nrflns 2 Nparams )]1 / 2
.
w21 5 s2(F) 1 0.0010F2.

2746
F.-E. Hong et al. / Polyhedron 18 (1999) 2737–2747
3.3.2. Characterization of (15)
References
1H NMR (CDCl3): d 6.42 (s, 1H, –C≡CH), 5.27 (t, 2H,
J55.6 Hz, areneCr(CO)3), 5.59 (t, 1H, J56.0 Hz,
areneCr(CO)3), 5.90 (dd, J55.6 Hz, 2H, areneCr(CO)3),
7.46 (dd, J56.4 Hz, 4H, –Ph–). 13C NMR (CDCl3): d
72.91 (s, 1C, CH), 88.02 (1C, –C≡CH), 91.81, 95.12 (2C,
–C≡C–), 88.82, 94.57, 96.42 (5C, areneCr(CO)3), 106.73
(1C, ipso of areneCr(CO)3), 129.62, 130.83 (4C, –Ph–),
137.44, 137.88 (2C, ipso of –Ph–), 198.37, 199.18 (12C, 2
[1] F.-E. Hong, S.-C. Lo, M.-W. Liou, L.-F. Chou, C.-C. Lin, J.
Organomet. Chem. 516 (1996) 123.
[2] F.-E. Hong, S.-C. Lo, M.-W. Liou, Y.-T. Chang, C.-C. Lin, J.
Organomet. Chem. 506 (1996) 101.
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Co2(CO)6), 231.19 (3C, Cr(CO)3). IR (CH2Cl2): n(CO)
5
2091 (m), 2061 (s), 2030 (m), 1968 (m), 1897 (m) cm21
.
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(1994) 467.
MS m/z 910 (M1). Anal.: Calcd.: C, 40.91; H, 1.11.
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(1985) 3989.
Found: C, 40.48; H, 1.24.
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vol. 12, Elsevier, New York, 1995, p. 685.
3.3.3. Characterization of (17)
1H NMR (CDCl3): d 6.38 (s, 2H, –C≡CH), 7.28 (t,
J57.2 Hz, 1H, –Ph–), 7.45 (dd, J57.8 Hz, 2H, –Ph–),
7.68 (m, 1H, –Ph–). 13C NMR (CDCl3): d 72.62 (s, 2C,
C1), 89.18 (s, 2C, C2), 129.19 (s, 1C, C6), 129.33 (s, 2C,
C4), 132.20 (s, 1C, C5), 138.42 (s, 2C, C3), 199.08 (m,
12C, 2 Co2(CO)6). IR (CH2Cl2): n(CO) 52092 (s), 2060
(s), 2027 (s) cm21. MS m/z 698 (M1) Anal.: Calcd.: C,
37.86; H, 0.87. Found: C, 38.14; H, 1.00.
3.4. X-ray crystallographic studies
[15] M.J. Chetcuti, in: E.W. Abel, F.G.A. Stone, G. Wilkinson (Eds.),
Comprehensive Organometallic Chemistry II, Vol. vol. 10, Elsevier,
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Comprehensive Organometallic Chemistry II, Vol. vol. 12, Elsevier,
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Suitable crystals of (8b), (8c), (15), (17) and (10) were
sealed in thin-walled glass capillaries under nitrogen
atmosphere. The first four crystals were mounted on a
Siemens Smart CCD diffractometer; the fifth crystal was
mounted on a Siemens P4 diffractometer. The crystallo-
graphic data were collected using a u–2u scan mode with
Mo Ka radiation. The space group determination was
based on a check of the Laue symmetry and systematic
absences, and was confirmed by the structure solution. The
structure was solved by direct methods using Siemens
SHELXTL PLUS package [40]. All non-H atoms were located
from successive Fourier maps. Anisotropic thermal param-
eters were used for all non-H atoms and fixed isotropic for
H atoms that were refined using the riding model [41].
Crystallographic data of (8b), (8c), (10), (15) and (17)
are summarized in Table 7.
¨
¨
[21] U. Kruerke, W. Hubel, Chem. Ber. 94 (1961) 2829.
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Perkin I, (1973) 975.
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Chem. Soc., Perkin I (1973) 977.
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Metals, 2nd ed, Wiley, New York, 1994, Ch. 14.
[28] J.P. Collman, L.S. Hegedus, J.R. Norton, R.G. Finke, Principles and
Applications of Organotransition Metal Chemistry, University Sci-
ence Books, Mill Valley, CA, 1987.
Supplementary data
[29] The electron-withdrawing ability of the Cr(CO)3 fragment is similar
to NO2 group. The fact that the NO2 group deactivates the reactivity
of the benzene ring is well known.
[30] M.G. Bodner, L.J. Todd, Inorg. Chem. 13 (1974) 360.
[31] F.-E. Hong, J.-W. Liaw. C.-C. Lin, Unpublished results.
[32] J.S. Miller, Adv. Mater. 5 (1993) 587.
Supplementary data are available from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge
CB2 1EZ, UK on request, quoting the deposition number
CCDC 114041–CCDC 114045.
[33] J.S. Miller, Adv. Mater. 5 (1993) 671.
[34] O. Lavastre, J. Plass, P. Bachmann, S. Guesmi, G. Moinet, P.H.
Dixneuf, Organometallics 16 (1997) 184.
Acknowledgements
[35] C.E. Housecroft, B.F.G. Johnson, M.S. Khan, J. Lewis, P.R.
Raithby, M.E. Robson, D.A. Wilkinson, J. Chem. Soc., Dalton
Trans. (1992) 3171.
We thank the National Research Council of the R.O.C.
(Grant NSC-88-2113-M-005-022) for support.

F.-E. Hong et al. / Polyhedron 18 (1999) 2737–2747
2747
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XRD Corporation, Madison, Wisconsin, 1991.
(1977) 7546.
[41] Hydrogen atoms were ride on carbons or oxygens in their idealized
˚
[38] F. van Meurs, H. van Konigsveld, J. Organomet. Chem. 78 (1974)
positions and held fixed with the C–H distances of 0.96 A.
229.
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295.