Hydrogen bonding interaction of CpCo(Dithiolene) complex with monocyclic 2-pyridonyl substituent and unexpected formation of dithiolene-fused tricyclic pyridone derivative

Article abstract of DOI:10.1016/j.jorganchem.2009.04.022

One-pot reaction of [CpCo(CO)₂], elemental sulfur with some heterocycle-substituted alkynes (R-C{triple bond, long}C-HET) produced [CpCo(dithiolene)] complexes with ²PyOBn (2), with both ²PyOBn and 2-hydroxy-2-propyl group

Full text of DOI:10.1016/j.jorganchem.2009.04.022

Journal of Organometallic Chemistry 694 (2009) 2902–2911
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Journal of Organometallic Chemistry
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Hydrogen bonding interaction of CpCo(Dithiolene) complex with monocyclic
2-pyridonyl substituent and unexpected formation of dithiolene-fused
tricyclic pyridone derivative
*
Mitsushiro Nomura , Mami Kanamori, Yoshino Yamaguchi, Naoki Tateno, Chikako Fujita-Takayama,
*
Toru Sugiyama, Masatsugu Kajitani
Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1, Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
One-pot reaction of [CpCo(CO)2], elemental sulfur with some heterocycle-substituted alkynes (R–C„C–
HET) produced [CpCo(dithiolene)] complexes with 2PyOBn (2), with both 2PyOBn and 2-hydroxy-2-pro-
pyl groups (C(OH)Me2) (5), both 2Py and C(OH)Me2 (8), both 4Py and C(OH)Me2 (11), and with 4Py
substituent (13). A deprotection of benzyl group (Bn) from 2 with trimethylsilyl iodide formed
[CpCo(dithiolene)] with 2-pyridonyl substituent (3). Heating reaction of 8 without any base resulted in
the C(OH)Me2 group elimination to form the 2-pyridylethylenedithiolate complex (9), but 11 underwent
only dehydration at the C(OH)Me2 under heating. While the preparation of 5, the benzyl free complex (6)
was obtained as a main product. 6 has a dithiolene-fused tricyclic pyridone skeleton. The structures of 3,
5, 6, 8, and 11 were determined by X-ray diffraction studies. Intramolecular OHꢀ ꢀ ꢀN(2Py) hydrogen bon-
dings are found in 5 and 8, and an intermolecular OHꢀ ꢀ ꢀN(4Py) one is found in 11 at solid state. In the
2-pyridonyl complex 3, intermolecular NHꢀ ꢀ ꢀO and CH(dithiolene)ꢀ ꢀ ꢀO hydrogen bondings are observed.
8 showed an intermolecular Cpꢀ ꢀ ꢀCp face-to-face interaction. The tricyclic complex 6 exhibited lower
energy electronic absorption (kmax = 668 nm) compared with the others (kmax = 562–614 nm), due to
Received 10 March 2009
Received in revised form 16 April 2009
Accepted 21 April 2009
Available online 3 May 2009
Keywords:
Dithiolene
Tricyclic pyridone
Pyridine
Hydrogen bonding
Crystal structure
an extended p-conjugation of aromatic cobaltadithiolene ring.
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
proton source [6]. In addition, the oxo-molybdenum bisdithiolene
complex [Mo(O)(qdt)2] (qdt = quinoxaline-2,3-dithiolate) under-
goes thermally driven valence tautomerism by an intramolecular
charge transfer (M/L–CT) [10]. Nishihara et al. reported proton
and photo responsive [CpCo(dithiolene)], [M(dithiolene)2] and
[(P^P)M(dithiolene)] (M = Ni, Pd, Pt; P^P = diphosphine) complexes
with azobenzene unit due to those cis-trans isomerizations [11].
On the other hand, 2-pyridone derivatives have been attracted
due to their promising features as an important core structure
for the development of biologically active molecules [12]. Pharma-
ceuticals with the 2-pyridone structure have been investigated for
antitumor [13], antifungal [14], antibacterial [15], antiviral [16],
and antithrombotic agents [17]. In general, 2-pyridone derivatives
could be one of strong hydrogen bonding motifs by the NHꢀ ꢀ ꢀO
interaction. Dimeric hydrogen bonding interaction (Chart 2, A)
has been well known [18]. Wuest reported dipyridonyl acetylenes
which show dimeric (Chart 2, B) and polymeric hydrogen bonding
networks (Chart 2, C) [19]. Theoretical studies for dipyridonyl acet-
ylenes have been investigated [20].
Metal dithiolene complexes have been extensively investigated
due to their combination of functional properties, specific geome-
tries, and intermolecular interactions that confer them an enor-
mous interest in the field of magnetism [1], conductivities [2],
and optical properties [3]. On the other hand, metal dithiolene
complex biochemically functions as a coenzyme as well [4]. Some
model compounds relating to biochemically functional materials
have been studied by using oxo-molybdenum and oxo-tungsten
bisdithiolene complexes as oxo-transfer sources [5]. Garner and
Joule et al. reported some [CpCo(dithiolene)] (Cp =
g
5-cyclopenta-
dienyl) complexes having heterocycles such as 2-quinoxalinyl [6],
pteridin-6-yl [7], pyrano[2,3-b]quinoxaline [8], and pyrano[2,3-
g]pteridine [9] which can be also model compounds for a proton-
transfer (Chart 1). Among them, [CpCo(dithiolene)] with 2-quinox-
alinyl group shows 2eꢁ/2H+ reduction system in the presence of a
* Corresponding authors. Present address: Condensed Molecular Materials Lab-
oratory, RIKEN, 2-1, Hirosawa, Wako-shi, Saitama 351-0198, Japan. Tel.: +81 48 467
9412; fax: +81 48 462 4661.
E-mail addresses: m-nomura@sophia.ac.jp, mitsushiro@riken.jp (M. Nomura),
kajita-m@sophia.ac.jp (M. Kajitani).
In this work, we prepared [CpCo(dithiolene)] complex having
2-pyridonyl substituent which can be also an important metal
complex as a biochemically functional material and to be a hydro-
gen bonding network. Furthermore, 2-pyridonyl group may be
0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2009.04.022

M. Nomura et al. / Journal of Organometallic Chemistry 694 (2009) 2902–2911
2903
2. Results and discussion
Co
S
Co
S
S
S
2.1. Syntheses of CpCo(dithiolene) complexes using one-pot reaction
H
N
H
N
H
H
H
H
Garner and Joule et al. reported the synthesis of dithiolene’s
precursor (1,3-dithiol-2-one derivative) related to molybdopterin
from diisopropyl xanthogen disulfide and alkynes [22]. On the
other hand, many [CpCo(dithiolene)] complexes can be prepared
by one-pot reactions of CpCoI species, elemental sulfur and al-
kynes, which have been well developed in our research group
[23,24]. [CpCo(CO)2], elemental sulfur and 2-(benzyloxy)-6-ethyn-
ylpyridine (1) reacted in refluxing xylene for 17 h to form the
[CpCo(dithiolene)] complex with 2PyOBn substituent (2) in 26%
yield (Scheme 1). A deprotection of the benzyl group was per-
formed by using a conventional way [25]. The treatment of com-
plex 2 with excess trimethylsilyl iodide in refluxing CH2Cl2
resulted in the dithiolene complex with 2-pyridonyl substituent
(3) in 56% yield (Scheme 1). Both products 2 and 3 were identified
with spectroscopic data and elemental analyses. The 1H NMR of 2
and 3 showed dithiolene protons at 9.59 and 9.12 ppm, respec-
tively. In general, a ring current effect due to an aromatic dithio-
lene leads to a quite lower magnetic shift [26]. In 3, a broad
singlet signal for the NH group was found at 9.60 ppm. This is evi-
dence for an existence of pyridonyl substituent on the cobaltadi-
thiolene ring.
HO
Me
O
N
O
N
H
H
H
CO2Bn
pyrano[2,3-
b
]quinoxaline
pyrano[2,3-
g
]pteridine
Co
S
S
Co
S
O
S
N
N
N
Me
N
N
H
H
N
NMe2
2-quinoxalinyl
pteridin-6-yl
Chart 1. CpCo(dithiolene) complexes with heterocycles.
relatively easy to introduce to a molecule compared with pteridine
and quinoxaline analogues (Chart 1). Interestingly, we unexpect-
edly found two different pyridone-containing dithiolene com-
plexes. One is an expected pyridone-substituted dithiolene
complex to show a hydrogen bonding interaction, but the other
one is the dithiolene-fused tricyclic pyridone complex formed by
an unexpected intramolecular cyclization. Generally, multicyclic
pyridone derivatives are also biologically useful as antibacterial
agents [21]. Furthermore, this paper also reports on [CpCo(dithio-
lene)] complex having 2-pyridyl (2Py) or 4-pyridyl (4Py) substitu-
ent for purpose of a comparison.
The reaction of [CpCo(CO)2], elemental sulfur with 4-(6-(ben-
zyloxy)pyridin-2-yl)-2-methylbut-3-yn-2-ol (4) in refluxing xy-
lene gave the complex (5) with both 2PyOBn and 2-hydroxy-2-
propyl substituents (–C(OH)Me2) on the cobaltadithiolene ring in
18% yield, and formed the tricyclic complex (6) in 29% yield as well
(Scheme 2). 6 has a 2-pyridonyl substituent but the N atom binds
H
N
O
N
N
N
N
O
O
H
H
O
H
O
H
O
N
N
H
O
O
H
O
H
H
N
N
N
H
O
(A)
(B)
(C)
Chart 2. Dimeric and polymeric hydrogen bonding in 2-pyridone derivatives.
O
Ph
N
S
S
CO
CO
N
O
Ph
S8
+
+
Co
Co
xylene
reflux
H
H
1
2
CH2Cl2
reflux
Me3SiI
S
Co
S
N
H
O
H
3
Scheme 1.

2904
M. Nomura et al. / Journal of Organometallic Chemistry 694 (2009) 2902–2911
Ph
O
N
S
S
CO
CO
S
S
N
O
Ph
S8
+
+
Co
Co
+
Co
N
OH
O
OH
4
5
6
Scheme 2.
to the carbon on the 2-propyl group. In fact, no NH signal was
found in the 1H NMR spectrum of 6. A 1H NMR signal at
1.88 ppm (6H) indicates two equivalent Me groups, and evidences
that the tricyclic plane in 6 is quite planar. Formally, 6 is formu-
lated as [5–PhCH2OH]. Interestingly, the EI+ (70 eV) mass spectrum
of 5 resulted in 6+ (mass number = 346) as a fragment ion. Further-
more, refluxing xylene solution of 5 for 17 h was performed to af-
ford 6 in 25% yield. This result suggests that thermolysis of 5 forms
6 by elimination of PhCH2OH.
Jung and his coworker have reported that Me3SiI reacts with
ethers (R–O–R0) to form dealkylated products (R–OH and R0–OH)
[25]. An intermediate in this reaction is a silylated oxonium com-
pound (R–O+(SiMe3)–R0) and then one of two alkyl groups elimi-
nates. The silyl group is deprotected during workup process. In
the formation of 3, the reaction process can be explained by the
benzyl group elimination from 2 through the silylated oxonium
intermediate by Me3SiI. However, the formation of 6 from 5 occurs
by benzyl group elimination without Me3SiI. We assume that 2Py
group in complex 5 can deprotonate from the C(OH)Me2 group
through intramolecular OHꢀ ꢀ ꢀN(2Py) hydrogen bonding (Fig. 1).
After that, an intramolecular cyclization occurs to make a five
membered ring for 6, followed by elimination of benzyl alcohol
(PhCH2OH). However, a detailed formation mechanism of cycliza-
tion has not been clear yet. Anyway, we thought that the intramo-
lecular hydrogen bonding of the dithiolene complex having 2Py
group was interesting to make a unique reactivity. Due to this rea-
son, we decided to prepare [CpCo(dithiolene)] complex having 2Py
group for intramolecular hydrogen bonding, and also synthesized
the complex with 4Py group for intermolecular hydrogen bonding
by purpose of comparison.
reaction of 8 in refluxing xylene (140 °C) produced 9 in low yield
but the reaction in refluxing trans-decahydronaphthalene (b.p.
185 °C) gave 9 in higher yield (39%). This result indicates that 8
eliminates one acetone fragment from 9. We assume that the 2Py
group deprotonates from the hydroxyl group on C(OH)Me2, be-
cause an OHꢀ ꢀ ꢀN(2Py) intramolecular hydrogen bonding is ob-
served (see Fig. 2 and Table 1). As previously reported, the
C(OH)Me2 group is deprotected by treatment with a strong base
such as NaOH [27], but a weak base such as pyridine can not make
it. However, most probably, the intramolecular deprotonation by
2Py group mediates the C(OH)Me2 group elimination to form 9.
In fact, no reaction occurred in thermal reaction of 8 in the pres-
ence of H2SO4. In this case, H2SO4 might protonate the 2Py group.
Here we assume that the protonated 2Py (pyridinium) can make
an intramolecular hydrogen bonding such as NH(2Py)ꢀ ꢀ ꢀOH in an
acidic condition. Accordingly, this intramolecular hydrogen bond-
ing prevents the protonation of OH group by H2SO4. Normally,
dehydration of alcohol is hard to occur without protonation of
OH group.
The reaction of [CpCo(CO)2], elemental sulfur with 2-methyl-4-
(pyridin-4-yl)but-3-yn-2-ol (10) in refluxing xylene formed the
complex (11) with both 4Py and C(OH)Me2 substituents on the
cobaltadithiolene ring in 22% yield, and the complex (12) with both
4Py and 2-propenyl substituents in 4% yield (Scheme 4). A 2-prope-
nyl free complex (13, Scheme 4) was not obtained at all. The 1H
NMR of 12 exhibited an olefinic proton at 5.05 ppm (singlet, 2H),
and revealed absence of the OH proton. This result suggested exis-
tence of C@CH2 moiety. A dehydration of 11 plausibly gives 12. In
fact, the thermal reaction of 11 in refluxing trans-decahydronaph-
thalene for 18 h formed 12 in 79% yield but did not give 2-propenyl
free complex 13. The dehydration reaction of 11 in the presence of
H2SO4 in refluxing xylene gave higher yield of 12 (89%). One reason
for no formation of 13 may be absence of an intramolecular OHꢀ ꢀ ꢀN
hydrogen bonding or intermolecular OHꢀ ꢀ ꢀN(4Py) hydrogen bond-
ing in 11 (see Fig. 3 or Table 1) is not enough effective for deproto-
nation of C(OH)Me2 group.
The reaction of [CpCo(CO)2], elemental sulfur with 2-methyl-4-
(pyridin-2-yl)but-3-yn-2-ol (7) in refluxing xylene formed the
complex (8) with both 2Py and C(OH)Me2 substituents on the
cobaltadithiolene ring in 23% yield, and CpCo 2-pyridylethylenedi-
thiolate complex (9) in 3% yield as a byproduct (Scheme 3). 9 has
been synthesized from 1,3-dithiol-2-thione derivative by Garner
and Joule [6b], but been not characterized. The 1H NMR of 9
showed a dithiolene proton at 9.66 ppm. The mass spectrum 8 re-
sulted in the fragmentation of 9+ (mass number = 291). Thermal
A deprotection of C(OH)Me2 group with NaOH from alkyne 10
formed 4-ethynylpyridine [27]. The 2-propenyl free complex (13)
was obtained by the reaction of [CpCo(CO)2], elemental sulfur with
4-ethynylpyridine in refluxing xylene in 30% yield (Scheme 4). 13
was characterized by spectroscopic data and elemental analysis.
However, treatment of 11 with NaOH resulted in decomposition
of the product. In addition, no reaction was confirmed by the reac-
tion of 11 in xylene solution containing excess pyridine.
2.2. X-ray structures of CpCo(dithiolene) complexes
Molecular and crystal structures of 3, 5, 6, 8, and 11 were deter-
mined by single crystal X-ray structure analyses. Those ORTEP
drawings and crystal packing diagrams are shown in Figs. 1–5.
The selected bond lengths, bond angles in the cobaltadithiolene
moiety, hydrogen bonding distances and dihedral angles are sum-
marized in Table 1.
The Co–S bond lengths are 2.08–2.10 Å except for 6. In typical,
the Co–S lengths in [CpCo(dithiolene)] complexes are almost
Fig. 1. The ORTEP drawing of 5 with intramolecular OHꢀ ꢀ ꢀN hydrogen bonding
(thermal ellipsoids 30% probability). Two oxybenzyl groups A and B are disordered
(A:B = 54:46).
2.1 Å. Sellmann et al. explained that a strong
p-donation from

M. Nomura et al. / Journal of Organometallic Chemistry 694 (2009) 2902–2911
2905
N
S
N
CO
CO
S
S
N
S8
+
+
Co
Co
+
Co
OH
S
H
OH
7
8
9
Scheme 3.
there is an intermolecular Cpꢀ ꢀ ꢀCp interaction (Fig. 1). The face-
to-face distance is c.a. 3.5 Å. Some previous paper have reported
similar Cpꢀ ꢀ ꢀCp interactions in the paramagnetic [CpNi(bdt)]
(bdt = benzene-1,2-dithiolate) [29], [CpNi(bds)] (bds = benzene-
1,2-diselenolate) [29], [CpNi(adt)] (adt = acrylonitrile-2,3-dithiol-
ate) [30]. Those
strong magnetic interactions [31].
p p interactions are weak bonding but undergo
ꢁ
Figs. 4 and 5 exhibit the ORTEP drawings of 3 and 6. Dimeric
intermolecular hydrogen bonding interactions are found in the
crystal packing of 3 (Fig. 4). There are NHꢀ ꢀ ꢀO (1.908(13) Å) bond-
ing between 2-pyridonyl groups and CHꢀ ꢀ ꢀO (2.283(16) Å) hydro-
gen bonding between dithiolene ring and 2-pyridonyl group. The
latter result suggests that the dithiolene proton could be some-
what acidic. In actual, an aromatic dithiolene proton appears
around 9 ppm in 1H NMR spectra [26] whose d value is lower mag-
netic field than that of a typical aromatic compound. This dimeric
hydrogen bonding makes a slightly flat geometry. Actually, the
dihedral angle of cobaltadithiolene/pyridonyl is 22.4° (Fig. 4 and
Table 1). We consider that this is an interesting two-dimensional
hydrogen bonding involving the dithiolene proton. Furthermore,
the dihedral angle of that in the tricyclic pyridone complex 3 is
0.9° due to direct binding of the N atom to the carbon on the 2-pro-
pyl group. A remarkable structural feature of 6 is short C–C bond
length in the five-membered ring moiety. In general, average C–C
single bond length is 1.54 Å as well known. The C1–C8 and C2–
C3 bond lengths are shorter than 1.54 Å. This fact indicates that
the five-membered ring is conjugated with dithiolene and pyri-
done rings.
Fig. 2. (a) The ORTEP drawing of 8 with intramolecular OHꢀ ꢀ ꢀN hydrogen bonding
(dotted line). The thermal ellipsoids are drawn at 30% probability level. (b)
Projection view along the b-axis of the unit cell of 8 exhibiting intermolecular
Cpꢀ ꢀ ꢀCp interaction (shown by an arrow).
2.3. Electronic absorption spectra and electrochemical behavior
UV–Vis spectral data and CV data were obtained in dichloro-
methane solution. Those absorption maxima (kmax/nm) and redox
potentials (vs. Fc/Fc+) are summarized in Table 2. The UV–Vis spec-
tra and cyclic voltammograms of 5 and 6 are shown in Figs. 6 and 7.
Most [CpCo(dithiolene)] complexes prepared in this work showed
kmax around 560–610 nm in dichloromethane solution in visible re-
gion, except for 6. These kmax results are similar to those of typical
sulfur to metal shortens the M–S bond [28]. However, the Co–S
bond length in 6 is longer than those of the others (Table 1, 2.
13–2.14 Å). We consider that the
calize the whole -electrons in the plane. In this case,
donation from S to M can be weaker than those of less
complexes 3, 5, 8, and 11. Therefore, there is an extended
p
-extended system in 6 can delo-
-electron
-extended
-conju-
p
p
p
[CpCo(dithiolene)] [31,32] and [Cp*Co(dithiolene)] (Cp* = 5-pen-
g
p
tamethylcyclopentadienyl) [33] complexes previously reported.
On the other hand, 6 resulted in the kmax at 668 nm (Table 2).
While compared 6 with its precursor 5, interestingly there are
95 nm differences (Fig. 6). Most probably, the lower energy absorp-
gation between cobaltadithiolene ring and pyridonyl group in 6. In
fact, the tricyclic pyridone plane is quite planar (Fig. 5). In addition,
the long Co–S bond in 6 slightly modifies the bond angles in cobalt-
adithiolene ring (Table 1). According to dihedral angles of Cp/
cobaltadithiolene, the Cp rings are located at perpendicular posi-
tion with regards to the cobaltadithiolene ring.
Figs. 1–3 display the molecular structures of 5, 8 and 11. In 5,
two oxybenzyl groups are disordered (Fig. 1). 5 and 8 have intra-
molecular OHꢀ ꢀ ꢀN(2Py) hydrogen bondings whose distances are
1.958(33) and 1.830(3) Å, and 11 has an intermolecular OHꢀ ꢀ ꢀN(4-
Py) one whose distance is 1.856(3) Å. Those hydrogen bondings re-
sult in difference of dihedral angle between cobaltadithiolene and
pyridyl rings. The cobaltadithiolene/2Py angles in 5 and 8 are
50.490° and 40.843° but the cobaltadithiolene/4Py angle in 11 is al-
most right angle (Table 1, 92.946°). In the crystal packing of 8,
tion caused by an extended
p-conjugation of tricyclic pyridone
plane. According to some previous reports, some
p
-extended
[CpCo(dithiolene)] complexes show lower energy absorption at
678 nm for [CpCo(dmit)] [32] and at 677 nm for [Cp*Co(dmit)]
(dmit = C3S5, 1,3-dithiol-2-thione-4,5-dithiolate).[33] The dinucle-
ar [Cp*Co(btt)CoCp*] (btt = benzene-1,2,4,5-tetrathiolate) exhibits
visible absorption at 677 nm [33].
The CV of [CpCo(dithiolene)] complexes displayed a reversible
reduction wave and some irreversible oxidation waves. Those
reductions are attibuted to the central metal, formally CoIII/CoII
couple. Namely, those reduction potentials correlate with a substi-
tuent effect on the cobaltadithiolene ring. The reduction potentials

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M. Nomura et al. / Journal of Organometallic Chemistry 694 (2009) 2902–2911
Table 1
Selected bond lengths (Å), bond angles (°), hydrogen bonding distances (Å) and dihedral angles (°).
3
5
6
8
11
Bond length
Co1–S1
Co1–S2
S1–C1
S2–C2
C1–C2
2.108(2)
2.107(2)
1.694(8)
1.719(7)
1.351(10)
2.0837(9)
2.0813(9)
1.707(3)
1.718(3)
1.361(4)
2.143(3)
2.129(3)
1.709(10)
1.719(10)
1.36(1)
2.0863(17)
2.0885(14)
1.719(5)
1.716(5)
1.375(5)
2.094(3)
2.106(3)
1.709(11)
1.723(11)
1.389(15)
Bond angle
S1–Co1–S2
Co1–S1–C1
Co1–S2–C2
S1–C1–C2
S2–C2–C1
90.89(9)
105.6(3)
105.5(2)
119.7(6)
118.2(6)
89.95(3)
93.4(1)
90.43(6)
89.98(13)
106.3(4)
108.8(3)
121.0(8)
113.8(8)
107.74(11)
107.24(11)
117.3(2)
102.8(3)
102.2(4)
120.4(8)
121.1(8)
106.69(16)
107.79(13)
118.7(4)
117.8(2)
116.4(3)
Hydrogen bonding
OHꢀ ꢀ ꢀN
–
1.958(33)b
–
–
–
–
–
1.830(3)b
–
–
1.856(11)a
–
–
NHꢀ ꢀ ꢀO
1.908(13)a
2.283(16)a
CHꢀ ꢀ ꢀO
Dihedral angle
Cp/CoS2C2
CoS2C2/pyridyl
CoS2C2/pyridonyl
90.9
–
22.4
90.144
50.490
–
87.6
–
0.9
89.342
40.843
–
91.990
92.946
–
a
Intermolecular hydrogen bonding.
Intramolecular hydrogen bonding.
b
N
N
N
S
S
CO
Co
CO
S
S
S8
+
+
Co
+
Co
OH
OH
10
11
12
NaOH
N
H
N
S
S
CpCo(CO)2 + S8
Co
H
13
Scheme 4.
of complexes having electron-donating C(OH)Me2 group (8 at
ꢁ1.30 V and 11 at ꢁ1.31 V) are more negative than those of com-
parable complexes without the substituent (9 at ꢁ1.25 V and 13
at ꢁ1.25 V). The reduction potentials of complexes with pyridyl
group (2 at ꢁ1.23 V and 5 at ꢁ1.29 V) are more negative than those
of comparable complexes with pyridonyl group (3 at ꢁ1.06 V and 6
at ꢁ1.03 V) (Fig. 7).
porating a dithiolene proton. This result really indicates that the
dithiolene proton is not only an aromatic ring proton involving ring
current effect but also an acidic one. In future, asymmetric dithio-
lene complexes involving a dithiolene proton, which formulated as
[M(S2C2(R, H))n], will be good materials to make a hydrogen bond-
ing network. As also one of interesting results in this work, we
unexpectedly obtained dithiolene-fused tricyclic pyridone deriva-
tive (6) by an intramolecular cyclization and its extended p-conju-
gation was observed.
3. Conclusion
This work aimed to synthesize [CpCo(dithiolene)] complexes
bearing pyridonyl derivative followed some previous works by
Garner and Joule [6–9]. [CpCo(dithiolene)] complexes with 2-pyri-
donyl substituent (3) revealed intermolecular NHꢀ ꢀ ꢀO and
CH(dithiolene)ꢀ ꢀ ꢀO hydrogen bondings. Some early works reported
[Ni(dithiolene)2] and [CpCo(dithiolene)] bearing amide and car-
boxylic acid groups, and these complexes have NHꢀ ꢀ ꢀO,
NHꢀ ꢀ ꢀS(dithiolene) and OHꢀ ꢀ ꢀO hydrogen bondings [34,35]. Our
case is more interesting because it is rare hydrogen bonding incor-
4. Experimental
4.1. Materials and instrumentation
All reactions were carried out under an argon atmosphere by
means of standard Schlenk techniques. All solvents for chemical
reactions were dried and distilled by Na-benzophenone for xylene
and trans-decahydronaphthalene or CaH2 for dichloromethane
before use. 2-(benzyloxy)-6-ethynylpyridine (1) [36], 2-methyl-4-

M. Nomura et al. / Journal of Organometallic Chemistry 694 (2009) 2902–2911
2907
Fig. 4. (a) The ORTEP drawing of
3
(thermal ellipsoids 30% probability). (b)
Projection view along the a-axis of the unit cell of 3 showing intermolecular OHꢀ ꢀ ꢀN
and CHꢀ ꢀ ꢀN hydrogen bondings.
Fig. 3. (a) The ORTEP drawing of 11. The thermal ellipsoids are drawn at 30%
probability level. (b) Projection view along the a-axis of 11 showing intermolecular
OHꢀ ꢀ ꢀN hydrogen bonding.
(pyridin-2-yl)but-3-yn-2-ol (7) [37], 2-methyl-4-(pyridin-4-yl)-
but-3-yn-2-ol (10) [27], 4-ethynylpyridine [27], 2-ethynylpyridine
[38], 2-(benzyloxy)-6-bromopyridine [39], and [CpCo(CO)2] [40]
were prepared by literature method. 2-Methylbut-3-yn-2-ol and
trimethylsilyl iodide were obtained from Tokyo Chemical Industry
Co., Ltd. (PPh3)2PdCl2, CuI, Silica gel (Wakogel C-300) and alumi-
num oxide were purchased from Wako Pure Chemical Industries,
Ltd. Mass and IR spectra were recorded on a JEOL JMS-D300 and
a
Shimadzu Model FTIR 8600PC instruments, respectively.
UV–Vis spectra were recorded on a Hitachi Model UV-2500PC
spectrometer. Elemental analyses were determined by using a
Shimadzu PE2400-II instrument.
Fig. 5. The ORTEP drawings of 6 for (a) top view and (b) side view. (thermal
ellipsoids 30% probability). Selected bond lengths except for dithiolene moiety: C1–
C8 1.49(1), C2–C3 1.45(1), C3–C4 1.37(1), C4–C5 1.39(1), C5–C6 1.37(1), C6–C7
1.45(1), N1–C7 1.41(1), N1–C8 1.52(1).
4.2. Synthesis of CpCo(dithiolene) complex with 2PyOBn group (2)
[CpCo(CO)2] (1.5 ml, d = 1.278 g mlꢁ1, 10.7 mmol), elemental
sulfur (0.60 g, 18.75 mmol) and 2-(benzyloxy)-6-ethynylpyridine
(1) (1.89 g, 9.03 mmol) were reacted in refluxing xylene (50 ml)
for 17 h. Solvent was removed under reduced pressure, and the
residue was separated by column chromatography on silica gel
(eluent: n-hexane/dichloromethane = 1:1(v/v)) to obtain a dark
blue component. A product was further purified by recrystalliza-
tion from n-hexane/dichloromethane (3:1(v/v)). A dark blue prod-
uct (2) was obtained in 26% (dark blue solid, 0.937 g, 2.36 mmol)
yield.
(CDCl3, 500 MHz, vs. TMS) d = 9.59 (s, 1H, dithiolene-H), 7.78 (d,
J = 7.6 Hz, 1H, Py), 7.57 (t, J = 7.6 Hz, 1H, Py), 7.49 (d, J = 7.3 Hz,
2H, Ph), 7.37 (t, J = 7.3 Hz, 2H, Ph), 7.27 (t, J = 7.3 Hz, 1H, Ph),
6.79 (d, J = 7.6 Hz, 1H, Py), 5.45 (s, 2H, CH2), 5.41 (s, 5H, Cp). 13C
NMR (CDCl3, 125 MHz, vs. TMS) d = 169.8, 162.7, 159.6, 153.7,
139.5, 137.6, 128.4, 128.2, 127.8, 112.8, 109.6, 79.4 (Cp), 67.4
(CH2). UV–Vis (CH2Cl2) kmax/nm (e) 338 (11300), 599 (11000). IR
Complex 2. Mass (EI+, 70 eV) m/z (rel. intensity) 397 ([M+], 93),
331 ([M+ –CpH], 21), 320 ([M+ –Ph], 10), 306 ([M+ –CH2Ph], 18),
188 ([CpCoS2+], 22), 124 ([CpCo+], 13), 91 (CH2Ph+, 100). 1H NMR
(KBr disk) 1585, 1568, 1454, 1427, 1265, 1211, 1049, 984, 835,
795 cmꢁ1. Anal. Calcd. For C19H16CoNOS2: C, 57.42; H, 4.06; N,
3.52. Found: C, 57.50; H, 4.05; N, 3.48%.

2908
M. Nomura et al. / Journal of Organometallic Chemistry 694 (2009) 2902–2911
Table 2
UV–Vis spectral data (kmax/nm) and redox potentials (vs. Fc/Fc+) of [CpCo(dithiolene)] complexes taken from cyclic voltammetry.
Absorption maxima kmax/nm (
e
Mꢁ1 cmꢁ1
)
E1/2 (red)/V
Ep (ox)/V
2
3
5
6
8
9
11
12
13
338 (11300), 599 (11000)
362 (15600), 614 (9000)
300 (27100), 573 (7700)
289 (12800), 343 (6300), 364 (8700), 374 (7500), 668 (5800)
406 (1600), 574 (10300)
294 (19600), 356 (3700), 589 (7200)
413 (1600), 562 (9200)
417 (1500), 587 (9900)
ꢁ1.23
ꢁ1.06
ꢁ1.29
ꢁ1.03
ꢁ1.30
ꢁ1.25
ꢁ1.31
ꢁ1.22
ꢁ1.25
0.56
0.61
0.62
0.60
0.61
0.58
0.62
0.75
0.65
364 (5200), 583 (9900)
reaction. Complex 2 (0.203 g, 0.511 mmol) reacted with trimethyl-
silyl iodide (0.3 ml, 2.19 mmol) in refluxing CH2Cl2 (10 ml) for 4 h.
Silica gel was added into the reaction mixture. The resulted mix-
ture was replaced to column chromatography on silica gel, and a
blue component was separated with ethyl acetate. All solvents
were removed under reduced pressure. A blue solid was further
purified by recrystallization from n-hexane/dichloromethane
(1:1(v/v)). A blue product (3) was obtained in 56% (greenish blue
solid, 88 mg, 0.286 mmol) yield.
Complex 3. Mass (EI+, 70 eV) m/z (rel. intensity) 307 ([M+], 100),
241 ([M+ –CpH], 30), 188 ([CpCoS2+], 65), 124 ([CpCo+], 26). 1H
NMR (CDCl3, 500 MHz, vs. TMS) d = 9.60 (br-s, 1H, NH), 9.12 (s,
1H, dithiolene-H), 7.36 (dd, J = 7.0, 6.5 Hz, 1H, Pyridone), 6.59–
6.62 (m, 2H, Pyridone), 5.46 (s, 5H, Cp). 13C NMR (CDCl3,
125 MHz, vs. TMS) d = 160.1, 157.8, 144.0, 141.4, 118.8, 103.6,
77.2 (Cp). UV–Vis (CH2Cl2) kmax/nm (e) 362 (15600), 614 (9000).
IR (KBr disk) 1643, 1591, 1539, 1464, 980, 833, 787 cmꢁ1. Anal.
Calcd. For C12H10CoNOS2: C, 46.90; H, 3.28; N, 4.56. Found: C,
47.12; H, 3.09; N, 4.27%.
Fig. 6. UV–Vis spectra of
5 and 6 in dichloromethane solution (c = c.a.
5.0 ꢂ 10ꢁ5 mol dmꢁ3) at room temperature.
4.4. Synthesis of 4-(6-(benzyloxy)pyridin-2-yl)-2-methylbut-
3-yn-2-ol (4)
2-(Benzyloxy)-6-bromopyridine (0.50 ml, 3.6 mmol) and 2-
methylbut-3-yn-2-ol (0.40 ml, 4.0 mmol) were reacted in the pres-
ence of (PPh3)2PdCl2 (50 mg, 0.07 mmol) and CuI (7 mg,
0.04 mmol) in diethylamine (15 ml) at room temperature for
17 h. After the reaction, solvent was removed under reduced pres-
sure. 100 ml of water was added and then organic component was
extracted with 200 ml of diethyl ether. The resulted organic layer
was dried with magnesium sulfate, and then it was filtered. The re-
sulted filtrate was evaporated under reduced pressure. The mix-
ture was separated by column chromatography on aluminum
oxide with diethyl ether. An oily pale yellow product was obtained
in 75% (720 mg, 2.69 mmol) yield. 1H NMR (CDCl3, 500 MHz, vs.
TMS) d = 7.54 (t, J = 7.6 Hz, 1H, Py), 7.33–7.47 (m, 5H, Ph), 7.06
(d, J = 7.6 Hz, 1H, Py), 6.76 (d, J = 7.6 Hz, 1H, Py), 5.40 (s, 2H,
CH2), 1.67 (s, 6H, Me). HR-Mass Calcd. For C17H17NO2: 267.1259.
Found: 267.1263%.
4.5. Reaction of [CpCo(CO)2], elemental sulfur with
4-(6-(benzyloxy)pyridin-2-yl)-2-methylbut-3-yn-2-ol (4)
[CpCo(CO)2] (0.4 ml, 2.86 mmol), elemental sulfur (0.174 g,
5.44 mmol) and 4-(6-(benzyloxy)pyridin-2-yl)-2-methylbut-3-yn-
2-ol (4) (0.695 g, 2.60 mmol) were reacted in refluxing xylene
(20 ml) for 17 h. Solvent was removed under reduced pressure,
and the residue was separated by column chromatography on sil-
ica gel. A first product (5) was separated with n-hexane/dichloro-
methane = 1:1(v/v) and a second product (6) was separated with
dichloromethane/diethyl ether = 1:1(v/v). These products were
further purified by recrystallization from n-hexane/dichlorometh-
ane = 1:1(v/v). Complexes 5 and 6 were obtained in 18% (purple
Fig. 7. Cyclic voltammograms of 5 and 6 (c = 1 ꢂ 10ꢁ3 mol dmꢁ3 = 100 mV sꢁ1
, v ,
U
= 1.6 mm Pt disk) in dichloromethane solution containing 0.1 mol dmꢁ3 tetra-n-
butylammonium perchlorate at room temperature.
4.3. Synthesis of CpCo(dithiolene) complex with 2-pyridonyl
substituent (3)
A conventional conversion from benzyloxypyridine to pyridone
derivative written in literature [25] was performed for following

M. Nomura et al. / Journal of Organometallic Chemistry 694 (2009) 2902–2911
2909
solid, 0.217 g, 0.477 mmol) and 29% (dark grren solid, 0.263 g,
0.758 mmol) yields, respectively.
was changed to dark blue. After the reaction, solvent was removed
under reduced pressure. The residue was separated by column
chromatography on aluminum oxide (eluent = dichloromethane).
The dark blue product 9 was obtained in 39% (23 mg, 0.079 mmol)
yield.
Refluxing xylene solution (50 ml) of 8 (70 mg, 0.20 mmol) was
stirred for 18 h in the presence of H2SO4 (3 ll). No reaction was
Complex 5. Mass (EI+, 70 eV) m/z (rel. intensity) 455 ([M+], 5),
437 ([M+–H2O], 9), 397 ([M+–Me2CO], 3), 346 ([7+–1], 100), 332
([7+–Me], 31), 281 ([7+–CpH], 36), 188 ([CpCoS2+], 5), 124 ([CpCo+],
6), 91 ([CH2Ph+], 68). 1H NMR (CDCl3, 500 MHz, vs. TMS) d = 7.70 (t,
J = 7.6 Hz, 1H, Py), 7.55 (d, J = 7.6 Hz, 1H, Py), 7.28–7.41 (m, 5H, Ph),
7.20 (s, 1H, OH), 6.85 (d, J = 7.6 Hz, 1H, Py), 5.37 (s, 5H, Cp), 5.25 (s,
confirmed and 8 was recovered in 99%.
2H, CH2), 1.62 (s, 6H, Me). UV–Vis (CH2Cl2) kmax/nm (e) 300
(27100), 573 (7700). IR (KBr disk) 3271, 1417, 1296, 1198, 833,
745 cmꢁ1. Anal. Calcd. For C22H22CoNO2S2: C, 58.01; H, 4.87; N,
3.08. Found: C, 57.80; H, 4.81; N, 2.96%.
4.8. Reaction of [CpCo(CO)2], elemental sulfur with 2-methyl-4-
(pyridin-4-yl)but-3-yn-2-ol (10)
Complex 6. Mass (EI+, 70 eV) m/z (rel. intensity) 347 ([M+], 100),
332 ([M+–Me], 75), 281 ([M+–CpH], 62), 188 ([CpCoS2+], 5), 124
([CpCo+], 9). 1H NMR (CDCl3, 500 MHz, vs. TMS) d = 7.28 (dd,
J = 8.2, 6.0 Hz, 1H, Pyridone), 6.71 (d, J = 6.0 Hz, 1H, Pyridone),
6.47 (d, J = 8.2 Hz, 1H, Pyridone), 5.45 (s, 5H, Cp), 1.88 (s, 6H,
[CpCo(CO)2] (2.63 ml, 18.6 mmol), elemental sulfur (1.91 g,
37.2 mmol) and 2-methyl-4-(pyridin-4-yl)but-3-yn-2-ol (10)
(3.0 g, 18.6 mmol) were reacted in refluxing xylene (50 ml) for
17 h. Solvent was removed under reduced pressure, and the residue
was separated by column chromatography on aluminum oxide.
Two different fractions were separated with n-hexane/dichloro-
methane = 2:5(v/v). Both products were further purified by recrys-
tallization from n-hexane/dichloromethane = 1:1(v/v). Complexes
11 and 12 were obtained in 22% (purple solid, 1.43 g, 4.10 mmol)
and 4% (dark blue solid, 0.242 g, 0.73 mmol) yields, respectively.
Complex 11. Mass (EI+, 70 eV) m/z (rel. intensity) 349 ([M+],
100), 331 ([M+–H2O], 65), 188 ([CpCoS2+], 12), 124 ([CpCo+], 20).
1H NMR (CDCl3, 500 MHz, vs. TMS) d = 8.54 (d, J = 6.0 Hz, 2H, Py),
7.20 (d, J = 6.0 Hz, 2H, Py), 5.37 (s, 5H, Cp), 1.55 (s, 6H, Me). 13C
NMR (CDCl3, 125 MHz, vs. TMS) d = 176.9, 163.1 (dithiolene-C),
152.6, 148.9, 123.9 (Py), 80.0 (Cp), 70.7 (Me2COH), 32.9 (Me2COH).
Me). UV–Vis (CH2Cl2) kmax/nm (e) 343 (6300), 364 (8700), 374
(7500), 668 (5800). IR (KBr disk) 1651, 1558, 1531, 1456, 1099,
793 cmꢁ1. Anal. Calcd. For C15H14CoNOS2: C, 51.87; H, 4.06; N,
4.03. Found: C, 51.70; H, 4.00; N, 3.86%.
4.6. Reaction of [CpCo(CO)2], elemental sulfur with 2-methyl-4-
(pyridin-2-yl)but-3-yn-2-ol (7)
[CpCo(CO)2] (0.88 ml, 6.21 mmol), elemental sulfur (0.40 g,
12.4 mmol) and 2-methyl-4-(pyridin-2-yl)but-3-yn-2-ol (7) (1.0 g,
6.21 mmol) were reacted in refluxing xylene (50 ml) for 17 h. Sol-
vent was removed under reduced pressure, and the residue was sep-
arated by column chromatography on aluminum oxide. Two
different fractions were separated with n-hexane/dichlorometh-
ane = 2:5(v/v). Both products were further purified by recrystalliza-
tion from n-hexane/dichloromethane = 1:1(v/v). Complexes 8 and 9
were obtained in 23% (purple solid, 0.499 g, 1.43 mmol) and 3%
(dark blue solid, 0.074 g, 0.25 mmol) yields, respectively.
Complex 9 was directly prepared by the reaction of [CpCo(CO)2]
(1.37 ml, 9.7 mmol), elemental sulfur (0.621 g, 19.4 mmol) with 2-
ethynylpyridine (1.0 g, 9.7 mmol). This reaction mixture was re-
acted in refluxing xylene (50 ml) for 17 h. The product was isolated
in 26% (0.717 g, 2.464 mmol) yield by the same way as noted
above.
UV–Vis (CH2Cl2) kmax/nm (e) 413 (1600), 562 (9200). Anal. Calcd.
For C15H16CoNOS2: C, 51.57; H, 4.62; N, 4.01. Found: C, 51.75; H,
4.62; N, 3.99%.
Complex 12. Mass (EI+, 70 eV) m/z (rel. intensity) 331 ([M+],
100), 188 ([CpCoS2+], 14), 124 ([CpCo+], 34). 1H NMR (CDCl3,
500 MHz, vs. TMS) d = 8.55 (d, J = 7.6 Hz, 2H, Py), 7.43 (d,
J = 7.6 Hz, 2H, Py), 5.39 (s, 5H, Cp), 5.05 (s, 2H, CH2), 1.88 (s, 3H,
Me). 13C NMR (CDCl3, 125 MHz, vs. TMS) d = 173.1, 163.0 (dithio-
lene-C), 149.6, 149.4, 146.0 (Py), 122.8 (C@CH2), 118.2 (C@CH2),
77.3 (Cp), 23.6 (Me) UV–Vis (CH2Cl2) kmax/nm (e) 417 (1500), 587
(9900). Anal. Calcd. For C15H14CoNS2: C, 54.37; H, 4.26; N, 4.23.
Found: C, 54.25; H, 4.25; N, 4.41%.
Complex 8. Mass (EI+, 70 eV) m/z (rel. intensity) 349 ([M+], 100),
291 ([M+–Me2CO](9+), 79), 227 ([M+–Me2CO–S2], 30), 188
([CpCoS2+], 12), 124 ([CpCo+], 22). 1H NMR (CDCl3, 500 MHz, vs.
TMS) d = 8.44 (m, 1H, Py), 8.08 (d, J = 8.3 Hz, 1H, Py), 7.77 (dt,
J = 8.3, 5.9 Hz, 1H, Py), 7.28 (t, J = 5.9 Hz, 1H, Py), 5.35 (s, 5H, Cp),
1.56 (s, 6H, Me). 13C NMR (CDCl3, 125 MHz, vs. TMS) d = 182.2,
164.6 (dithiolene-C), 159.8, 146.6, 137.5, 125.7, 122.0 (Py), 80.1
(Cp), 74.4 (Me2COH), 30.9 (Me2COH). UV–Vis (CH2Cl2) kmax/nm
4.9. Synthesis of complex 12 from 11 under heating condition
Complex 11 (70 mg, 0.20 mmol) was reacted in refluxing trans-
decahydronaphthalene (50 ml) for 18 h. An initial purple solution
was changed to dark blue. After the reaction, solvent was removed
under reduced pressure. The residue was separated by column
chromatography on aluminum oxide (eluent = dichloromethane).
The dark blue product 12 was obtained in 79% (52 mg,
0.157 mmol) yield.
(e) 406 (1600), 574 (10300). Anal. Calcd. For C15H16CoNOS2: C,
51.57; H, 4.62; N, 4.01. Found: C, 51.53; H, 4.66; N, 4.01%.
Xylene solution (50 ml) of 11 (150 mg, 0.42 mmol) in the pres-
Complex 9. Mass (EI+, 70 eV) m/z (rel. intensity) 291 ([M+], 100),
227 ([M+–S2], 27), 188 ([CpCoS2+], 46), 124 ([CpCo+], 17). 1H NMR
(CDCl3, 500 MHz, vs. TMS) d = 9.66 (s, 1H, dithiolene-H), 8.55 (d,
J = 3.6 Hz, 1H, Py), 8.05 (d, J = 7.9 Hz, 1H, Py), 7.64 (dt, J = 7.9,
3.6 Hz, 1H, Py), 7.22 (t, J = 3.6 Hz, 1H, Py), 5.28 (s, 5H, Cp). 13C
NMR (CDCl3, 125 MHz, vs. TMS) d = 169.6, 156.3 (dithiolene-C),
159.0, 149.5, 136.8, 121.8, 119.9 (Py), 79.4 (Cp). UV–Vis (CH2Cl2)
kmax/nm (e) 294 (19600), 356 (3700), 589 (7200). Anal. Calcd. For
C12H10CoNS2: C, 49.48; H, 3.46; N, 4.81. Found: C, 49.34; H, 3.46;
N, 4.76%.
ence of H2SO4 (3 ll) was refluxed for 18 h. The product 12 was sep-
arated by the same way noted above, and was isolated in 89% yield
(124 mg, 0.274 mmol).
4.10. Reaction of [CpCo(CO)2], elemental sulfur with 4-ethynylpyridine
[CpCo(CO)2] (0.14 ml, 1.02 mmol), elemental sulfur (0.066 g,
2.02 mmol) and 4-ethynylpyridine (0.11 g, 1.02 mmol) were re-
acted in refluxing xylene (45 ml) for 4 h. Solvent was removed un-
der reduced pressure, and the residue was separated by column
chromatography on aluminum oxide (eluent: n-hexane/dichloro-
methane = 1:2(v/v)). Resulted dark blue product was further puri-
fied by recrystallization from n-hexane/dichloromethane. Complex
13 was obtained in 30% (dark blue solid, 0.089 g, 0.306 mmol)
yield.
4.7. Synthesis of complex 9 from 8 under heating condition
Complex 8 (70 mg, 0.20 mmol) was reacted in refluxing trans-
decahydronaphthalene (50 ml) for 18 h. An initial purple solution

2910
M. Nomura et al. / Journal of Organometallic Chemistry 694 (2009) 2902–2911
Table 3
Crystallographic data.
Compound
Formula
3
5
6
8
11
C12H10NOS2Co
307.27
C22H22CoNOS2
439.46
C15H14NOS2Co
347.33
C15H16CoNOS2
349.35
C15H16CoNOS2
349.35
FW (g molꢁ1
)
Crystal color
Crystal shape
Crystal size (mm)
Crystal system
Space group
T (K)
green
cubic
darkblue
platelet
0.35 ꢂ 0.225 ꢂ 0.025
monoclinic
P21 (No. 4)
298
green
purple
chunk
0.30 ꢂ 0.30 ꢂ 0.13
monoclinic
C2/c (No. 15)
298
purple
platelet
0.30 ꢂ 0.17 ꢂ 0.01
orthorhombic
Pbca (No. 61)
298
prismatic
0.30 ꢂ 0.17 ꢂ 0.03
monoclinic
P21/n (No. 14)
298
0.30 ꢂ 0.23 ꢂ 0.10
triclinic
ꢀ
P1 (No. 2)
298
a (Å)
b (Å)
c (Å)
8.859(1)
9.400(2)
8.383(1)
111.553(10)
101.99(1)
67.26(1)
597.1(2)
2
10.8938(13)
6.2634(7)
15.5231(17)
6.008(4)
19.204(4)
12.947(3)
29.859(3)
6.7005(4)
18.4393(16)
6.318(3)
18.303(9)
26.335(12)
a
(°)
b (°)
103.553(5)
98.24(3)
124.6952(10)
c
(°)
V (Å3)
1029.7(2)
2
1478.3(9)
4
3033.2(4)
8
3045(3)
8
Z
Diffractometer
four-circle
1.709
1.766
2920
2742 (0.015)
1596
CCD
1.417
1.047
8129
4637 (0.0236)
3641
four-circle
1.561
1.436
7428
3394 (0.042)
1480
CCD
1.530
1.400
11335
3400 (0.032)
2517
CCD
Dcalc (g cmꢁ3
)
1.524
1.395
22048
3487 (0.105)
1478
l
(mmꢁ1
)
Total reflections
Unique reflections (Rint
Unique reflections (I > 2r(I))
)
R1, wR2 (I > 3
R1, wR2 (I > 2
Goodness-of-fit
r
r
(I))
(I))
0.057, 0.080
0.054, 0.089
0.0346, 0.0652
1.004
0.0535, 0.1319
1.038
0.0541, 0.1338
1.073
1.500
1.230
Complex 13. Mass (EI+, 70 eV) m/z (rel. intensity) 291 ([M+],
100), 227 ([M+–S2], 35), 188 ([CpCoS2+], 45), 124 ([CpCo+], 20). 1H
NMR (CDCl3, 500 MHz, vs. TMS) d = 9.13 (s, 1H, dithiolene-H),
8.57 (d, J = 7.0 Hz, 2H, Py), 7.69 (d, J = 7.0 Hz, 2H, Py), 5.43 (s, 5H,
Cp). 13C NMR (CDCl3, 125 MHz, vs. TMS) d = 160.4, 157.1 (dithio-
1.0 mmol dmꢁ3 dichloromethane solutions of complexes contain-
ing 0.1 mol dmꢁ3 tetra-n-butylammonium perchlorate (TBAP) at
25 °C.
5. Supplementary material
lene-C), 150.3, 146.1, 120.5, (Py), 79.7 (Cp). UV–Vis (CH2Cl2) kmax
/
CCDC No. 723293 (for 3), 723294 (for 5), 723295 (for 6), 723296
(for 8), and 723297 (for 11) contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
nm ( ) 364 (5200), 583 (9900). Anal. Calcd. For C12H10CoNS2: C,
e
49.48; H, 3.46; N, 4.81. Found: C, 49.23; H, 3.70; N, 4.77%.
4.11. X-ray diffraction study
A single crystal of 3, 5, 6, 8, and 11 were obtained by recrystal-
lization from the dichloromethane solutions and then vapor diffu-
sion of n-hexane into those solutions. Crystals were mounted on
the top of a thin glass fiber. Measurements for 3 and 6 were made
on Rigaku AFC5S four-circle diffractometer, and for 5, 8, and 11
were made on Rigaku Mercury CCD diffractometer with graphite-
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