Formations and structures of cobalt dithiolene complexes with nitrogen group-substituted cyclopentadienyl ligands

Article abstract of DOI:10.1016/j.jorganchem.2006.02.003

The cobalt dithiolene complex with the sulfonylamide-substituted Cp ligand [(C₅H₄-NHTs)Co{S₂C₂(COOMe)₂}] (1, Ts = p-SO₂C₆H₄Me) reacted with TsOH · H₂O to give [(C₅H₄-NH₂)Co{S₂C₂(COOMe)(H)}] (2), [(C₅H₄-NHTs)Co(S₂C₂H₂)] (3) and [(C₅H₄-NHTs)Co{S₂C₂(COOMe)(H)}] (4). Complex 1 was dissolved in a basic aqueous solution, and the anion reacted with Me₂SO₄ to form the N-methylated product [{C₅H₄-N(Me)Ts}Co{S₂C₂(COOMe)₂}] (5); the carboxylic acid complex [{C₅H₄-N(Me)Ts}Co{S₂C₂(COOMe)(COOH)}] (6) formed by a base hydrolysis. The X-ray crystal structures of complexes 4-6 and the methylsulfonylamide-substituted Cp complex [(C₅H₄-NHMs)Co{S₂C₂(COOMe)₂}] (7, Ms = SO₂Me) were determined. In the crystal structures of complexes 4 and 7, intermolecular hydrogen bondings of NH?O (ca. 2.1 A?) and NH?S (ca. 3.1 A?) were observed. Complex 6 showed the OH?O intermolecular hydrogen bonding (ca. 1.6 A?) of COOH moiety between two molecules, and these two molecules were assembling each other. Complexes 5 and 6 showed an intramolecular π-π interaction between the aromatic cobaltadithiolene and benzene rings, and complex 5 also has intermolecular π-π interactions between two benzene rings, and between two cobaltadithiolene rings.

Full text of DOI:10.1016/j.jorganchem.2006.02.003

Journal of Organometallic Chemistry 691 (2006) 2691–2700
www.elsevier.com/locate/jorganchem
Formations and structures of cobalt dithiolene complexes with
nitrogen group-substituted cyclopentadienyl ligands
,1
*
*
Mitsushiro Nomura , Masatsugu Kajitani
Department of Chemistry, Faculty of Science and Technology, Sophia University, 7-1, Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
Received 16 September 2005; received in revised form 27 January 2006; accepted 2 February 2006
Available online 15 March 2006
Abstract
The cobalt dithiolene complex with the sulfonylamide-substituted Cp ligand [(C5H4-NHTs)Co{S2C2(COOMe)2}] (1, Ts = p-
SO2C6H4Me) reacted with TsOH Æ H2O to give [(C5H4-NH2)Co{S2C2(COOMe)(H)}] (2), [(C5H4-NHTs)Co(S2C2H2)] (3) and [(C5H4-
NHTs)Co{S2C2(COOMe)(H)}] (4). Complex 1 was dissolved in a basic aqueous solution, and the anion reacted with Me2SO4 to form
the N-methylated product [{C5H4-N(Me)Ts}Co{S2C2(COOMe)2}] (5); the carboxylic acid complex [{C5H4-N(Me)Ts}Co{S2C2(COO-
Me)(COOH)}] (6) formed by a base hydrolysis. The X-ray crystal structures of complexes 4–6 and the methylsulfonylamide-substituted
Cp complex [(C5H4-NHMs)Co{S2C2(COOMe)2}] (7, Ms = SO2Me) were determined. In the crystal structures of complexes 4 and 7,
˚
˚
intermolecular hydrogen bondings of NHꢀ ꢀ ꢀO (ca. 2.1 A) and NHꢀ ꢀ ꢀS (ca. 3.1 A) were observed. Complex 6 showed the OHꢀ ꢀ ꢀO inter-
˚
molecular hydrogen bonding (ca. 1.6 A) of COOH moiety between two molecules, and these two molecules were assembling each other.
Complexes 5 and 6 showed an intramolecular p–p interaction between the aromatic cobaltadithiolene and benzene rings, and complex 5
also has intermolecular p–p interactions between two benzene rings, and between two cobaltadithiolene rings.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Dithiolene; Hydrolysis; Sulfonylamide; X-ray structure; p–p interaction; Hydrogen bonding
1. Introduction
group includes pterin or pteridine analogues for a model
compound of Moco [5]. The pterin contains an amide
structure having an affinity for an organism, and the amide
group is interesting for study of a crystal structure study
containing a hydrogen bonding interaction. The chemistry
of a hydrogen bonding interaction has been investigated in
the studies of a metal dithiolene [6] and a tetrathiafulvalene
(TTF) compound [7].
We have reported the cobalt dithiolene complex (1) with
the sulfonylamide-substituted cyclopentadienyl ligand
[(C5H4-NHTs)Co{S2C2(COOMe)2}] (Ts = p-SO2C6H4Me).
An amide structure is included on the substituent of cobalt-
adithiolene ring in the pterin complex reported by Garner
[5] and other dithiolene complexes [6], but our complex 1
has an amide substituent on the Cp ring, which is also an
interesting complex as an organometallic compound. Com-
plex 1 can be synthesized by the phosphine- or phosphite-
induced imido-migration reaction: the reaction of the
imido-bridged cobalt dithiolene complex [CpCo{S2C2-
Molybdenum cofactors (Moco) are consisted of a
mononuclear molybdenum dithiolene structure with pterin
ligands [1]. In many cases, the mononuclear molybdenum
dithiolene complex has an active metal center for some
important oxo-transfer reactions (e.g., xanthine oxidase
[2], sulfite oxidase [3], DMSO reductase [4]). Garner et al.
have reported some cobalt dithiolene complexes that can
be formulated as [CpCo(dithiolene-HET)] (Cp = g5-cyclo-
pentadienyl) having heterocycles (HET), and the HET
*
Corresponding authors. Tel.: +33 2 23 23 57 87; fax: +33 2 23 23 67 32
(M. Nomura).
E-mail address: mitsushiro.nomura@univ-rennes1.fr (M. Nomura).
Present address: Equipe ‘‘Matiere Condensee et Systemes Electroac-
1
´
´
`
´
`
tifs’’ (MaCSE), UMR 6226 ‘‘Sciences Chimiques de Rennes’’ CNRS-
´
ˆ
Universite de Rennes1, Bat 10C, Campus de Beaulieu, 35042 Rennes
cedex, France.
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.02.003

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Scheme 1.
(COOMe)2}(NTs)] with PR3 undergoes an intramolecular
imido-migration to the Cp ring, and this reaction forms
the sulfonylamide-substituted Cp complex 1 (Scheme 1)
[8]. This is the first case of a nitrogen group migration to
the Cp ligand. Esteruelas et al. have later reported the
migration of an amino ligand (NR2) to the Cp ring in the
reaction of the osmium complex [CpOs(H)(Cl)(NR2)(PR3)]
[9]. These migration reactions are useful for the formation
of a nitrogen group-substituted Cp ligand, because such a
ligand is generally difficult to synthesize.
In this work, the conversion of the sulfonylamide group
(NHTs) in complex 1 was our strategy for other nitrogen
group-substituted Cp cobalt dithiolene complexes. Using
a hydrolysis reaction is one methodology for the conver-
sion of a sulfonylamide group. We report on the acid and
base hydrolysis of complex 1. Furthermore, we found that
complex 1 showed water-solubility at a basic condition.
Recently, the synthesis and reactivity of an organometallic
complex in an aqueous solution have been intensively
investigated [10]. The reaction of complex 1 was performed
in an aqueous solution. Moreover, we particularly report
on the X-ray crystal structures of four cobalt dithiolene
complexes with a nitrogen group-substituted cyclopenta-
dienyl ligand, and we discuss a molecular stacking con-
trolled by a hydrogen bonding and p–p interaction
between aromatic rings.
Although the only complex 2 was produced by a detosyla-
tion of complex 1, the all products 2–4 lost one or two
COOMe groups of cobaltadithiolene substituents. Pro-
posed reaction mechanisms of the COOMe loss are the acid
hydrolysis of the COOMe to form COOH group as a first
reaction, and then carbon dioxide is eliminated from the
COOH group when a heating is supplied. However, when
this reaction was performed without heating (at room tem-
perature), no reaction was confirmed. Therefore, in this
reaction condition, the COOMe group of complex 1 is eas-
ier to be hydrolyzed than the NHTs group. An acid hydro-
lysis of complex 1 with H2SO4 was attempted in an
aqueous solution, but a complicated decomposition was
resulted.
2.2. Reaction of complex 1 in basic solution
When complex 1 was added into an aqueous solution
containing excess NaOH, the complex was easily dissolved
at room temperature. When Me2SO4 was added into this
aqueous solution, and then a purple precipitation was
formed immediately. After the reaction mixture was
extracted with an organic solvent, products in the organic
layer were separated by a silica-gel column chromatogra-
phy. The N-methylated product [{C5H4-N(Me)Ts}-
Co{S2C2(COOMe)2}] (5) was obtained in 17% yield
(Scheme 3). Complex 1 did not directly react with Me2SO4
in an organic solvent (e.g., benzene or dichloromethane),
and complex 1 was not dissolved in a non-basic aqueous
solution. These results suggest that the acidic NHTs group
of complex 1 is deprotonated in a basic solution, and then
the generated anion [(C5H4-NTs)Co{S2C2(COOMe)2}]ꢁ is
dissolved for the aqueous solution. Furthermore, the reac-
tion described in Scheme 1 also produced the carboxylic
acid complex which can be formulated as [{C5H4-
N(Me)Ts}Co{S2C2(COOMe)(COOH)}] (6) as the main
product in 48% yield. The complex 6 was a very polar
2. Results and discussion
2.1. Reaction of complex 1 in acidic solution
The reaction of complex 1 with TsOH Æ H2O in refluxing
toluene (Scheme 2) gave [(C5H4-NH2)Co{S2C2(COO-
Me)(H)}] (2, 6% yield), [(C5H4-NHTs)Co(S2C2H2)] (3,
trace amount), and [(C5H4-NHTs)Co{S2C2(COOMe)(H)}]
(4, 26% yield (main product)). Complexes 2 and 3 were
somewhat air-sensitive in both a solution and a solid states.
Scheme 2.

M. Nomura, M. Kajitani / Journal of Organometallic Chemistry 691 (2006) 2691–2700
2693
Scheme 3.
product, and it could be separated by acetone/methanol
mixed-solvent using a silica-gel column chromatography.
We assume that complex 6 was formed by a base hydrolysis
of the COOMe group.
in singlet signals of low magnetic field of dithiolene protons
at 8.46, 8.98 and 9.11 ppm (vs. TMS in CDCl3), respec-
tively. These d values are lower than the magnetic field of
a typical olefin proton. This result is explained by the effect
of a strong ring current [11] in the five-membered cobalt-
adithiolene ring.
The crystal structures of complexes 4–6 were determined
by X-ray structure analyses. The ORTEP drawings
together with selected bond lengths and angles are shown
in Figs. 1a, 2a and 3a, respectively. The packing diagrams
are given in Figs. 1b, 2b and 3b. This paper also reports on
the X-ray crystal structure (Figs. 4a and b) of the meth-
2.3. Product identifications and X-ray crystal structure
analyses
1
The H NMR spectra of complexes 2–6 showed two
triplet signals in a cyclopentadienyl region, and these
results indicate that there is a mono-substituted cyclopen-
tadienyl ligand in complexes 2–6. Complexes 2–4 resulted
Fig. 1. (a) ORTEP drawing of [(C5H4-NHTs)Co{S2C2(COOMe)(H)}] (4). The thermal ellipsoids are drawn at 50% probability level. Selected bond
˚
lengths (A): Co1–S1 = 2.1770(7), Co1–S2 = 2.1800(9), S1–C1 = 1.703(2), S2–C2 = 1.676(3), C1–C2 = 1.485(4). Selected bond angles (ꢁ): S1–Co1–
S2 = 101.86(3), Co1–S1–C1 = 94.79(9), Co1–S2–C2 = 95.0(1), S1–C1–C2 = 123.6(2), S2–C2–C1 = 124.8(2). (b) Packing diagram of [(C5H4-
NHTs)Co{S2C2(COOMe)(H)}] (4) showing NHꢀ ꢀ ꢀO and NHꢀ ꢀ ꢀS hydrogen bondings and head-to-tail arrangement.

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Fig. 2. (a) ORTEP drawing of [{C5H4-N(Me)Ts}Co{S2C2(COOMe)2}] (5). One of two independent molecules is shown. The thermal ellipsoids are drawn
˚
at 50% probability level. Selected bond lengths (A): Co1–S1 = 2.101(1), Co1–S2 = 2.118(1), S1–C1 = 1.714(4), S2–C2 = 1.710(4), C1–C2 = 1.358(5).
Selected bond angles (ꢁ): S1–Co1–S2 = 91.98(4), Co1–S1–C1 = 104.9(1), Co1–S2–C2 = 104.4(1), S1–C1–C2 = 119.1(3), S2–C2–C1 = 119.6(3).
(b) Packing diagram of [{C5H4-N(Me)Ts}Co{S2C2(COOMe)2}] (5) showing p–p stacking of molecules.
ylsulfonylamide-substituted Cp complex [(C5H4-NHMs)-
Co{S2C2(COOMe)2}] (7, Ms = SO2Me) analogous to com-
plex 1, whose synthesis and spectroscopic data have been
reported previously [8a]. In complexes 4–7, the Co–S bond
other words, there is an pseudo-aromaticity in the cobalt-
adithiolene ring [14].
The mean deviations from the cobaltadithiolene plane
˚
are 0.0045 (4), 0.0048 (5), 0.0264 (6) and 0.0154 (7) A
˚
lengths of the cobaltadithiolene ring were 2.086–2.180 A
(Table 1). Therefore, these cobaltadithiolene rings are
extremely planar. The dihedral angles between the cobalt-
adithiolene and Cp planes are almost right angles (87.369
(4), 92.654 (5), 95.038 (6) and 90.713 (7) in Table 1).
Namely, these complexes have typical two-legged piano-
stool geometries identical to those of the 16-electron
CpCoIII [15], CpRhIII [16] and CpIrIII [17] dithiolene
complexes. In other cases, (g6-arene)RuII [18] and CpNiIII
(Table 1), and such values are shorter than the typical bond
˚
lengths of Co(III)–S (2.25–2.48 A) [12]. This can be
explained if the shorter bond length of the cobaltadithio-
lene ring is due to a p-electron donation from sulfur to
metal center [13]. Such p-electron donation undergoes a
delocalization of 6p electrons, and the electronic effect gives
a strong ring current [11] in a cobaltadithiolene ring. In

M. Nomura, M. Kajitani / Journal of Organometallic Chemistry 691 (2006) 2691–2700
2695
Fig. 3. (a) ORTEP drawing of [{C5H4-N(Me)Ts}Co{S2C2(COOMe)(COOH)}] (6). One of two independent molecules is shown. The thermal ellipsoids are
˚
drawn at 50% probability level. Selected bond lengths (A): Co1–S1 = 2.112(3), Co1–S2 = 2.100(2), S1–C1 = 1.693(7), S2–C2 = 1.709(8), C1–C2 = 1.37(1).
Selected bond angles (ꢁ): S1–Co1–S2 = 92.83(9), Co1–S1–C1 = 103.8(3), Co1–S2–C2 = 103.9(2), S1–C1–C2 = 120.0(6), S2–C2–C1 = 119.3(5).
(b) Packing diagram of [{C5H4-N(Me)Ts}Co{S2C2(COOMe)(COOH)}] (6) showing an assembly of two molecules in those COOH moieties.
[19] dithiolene complexes have similar two-legged piano-
stool structures as half-sandwich metal dithiolene
complexes.
complex 4 showed neither intramolecular nor intermolecu-
lar p–p interaction (Figs. 1a and b) though both aromatic
rings are located in parallel position (the dihedral angle
of benzene/cobaltadithiolene = 8.018ꢁ in Table 1).
Complex 4 was regularly arranged in head-to-tail posi-
tions (Fig. 1b), and the intermolecular distance between
the Cp carbons and the dithiolene carbon (C2) is close
In complexes 4 and 7 having an amide group, intermo-
lecular hydrogen bondings were observed. The N1Hꢀ ꢀ ꢀO
˚
˚
(ca. 3.7 A). In complexes 5 and 6, the benzene rings and
(carbonyl oxygen) distances were 2.072(3) A in complex
˚
cobaltadithiolene rings are placed face-to-face at a distance
4, and 2.172(7) A in complex 7, and the N1Hꢀ ꢀ ꢀS (dithio-
˚
˚
of ca. 3.5 A (Figs. 2b and 3b), and especially both rings are
lene sulfur) distances were 3.130(2) A in complex 4 and
˚
quite parallel in complex 6 because the dihedral angle of
benzene/cobaltadithiolene is 2.845ꢁ (Table 1). This ten-
dency is also found in the crystal structure of complex 1
[8a]. We assume that there are intramolecular p–p interac-
tions between the two aromatic rings. Furthermore, inter-
molecular p–p interactions between two benzene rings
3.110(5) A in complex 7 (Table 1). Complex 7 has an alter-
nate stacking structure with the intermolecular hydrogen
bonding (Fig. 4b). In previous reports, we already reported
an intermolecular hydrogen bonding in complex
1
˚
˚
(N1Hꢀ ꢀ ꢀO = 1.946(23) A and N1Hꢀ ꢀ ꢀS = 2.877(34) A)
[8a] and in the cobalt dithiolene complex formulated as
˚
(ca. 3.7 A) and between two cobaltadithiolene rings (ca.
[CpCo{S2C2(COOMe)(CONHTs)}]
(2) A and N1Hꢀ ꢀ ꢀS = 3.5419(7) A) [20]. Mashima et al.
(N1Hꢀ ꢀ ꢀO = 2.144-
˚
˚
˚
4.5 A) were found in complex 5 (Fig. 2b). Unexpectedly,

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Fig. 4. (a) ORTEP drawing of [(C5H4-NHMs)Co{S2C2(COOMe)2}] (7). The thermal ellipsoids are drawn at 50% probability level. Selected bond lengths
˚
(A): Co1–S1 = 2.107(2), Co1–S2 = 2.096(2), S1–C1 = 1.718(5), S2–C2 = 1.719(6), C1–C2 = 1.355(7). Selected bond angles (ꢁ): S1–Co1–S2 = 92.45(7),
Co1–S1–C1 = 104.5(2), Co1–S2–C2 = 104.5(2), S1–C1–C2 = 119.0(4), S2–C2–C1 = 119.5(4). (b) Packing diagram of [(C5H4-NHMs)Co{S2C2-
(COOMe)2}] (7) showing NHꢀ ꢀ ꢀO and NHꢀ ꢀ ꢀS hydrogen bondings and a molecular stacking.
˚
have reported the binuclear ruthenium dithiolene complex
bridged by the g2-hydrazine ligand [(g6-C6Me6)Ru-
(S2C6H4)]2 (g2-NH2NH2), which has the NHꢀ ꢀ ꢀS hydrogen
bonding (3.18 and 3.22 A) [21]. Recently, the square-planar
nickel bisdithiolene complexes with amide groups have
been reported; they show NHꢀ ꢀ ꢀO intermolecular hydrogen

M. Nomura, M. Kajitani / Journal of Organometallic Chemistry 691 (2006) 2691–2700
2697
Table 1
Bond lengths, intermolecular hydrogen bonding distances, mean deviations from cobaltadithiolene plane, and dihedral angles of cobalt dithiolene
complexes
1a
4
5b
6b
7
˚
Bond length (A)
Co1–S1
Co1–S2
S1–C1
S2–C2
C1–C2
2.112(3)
2.1770(7)
2.1800(9)
1.703(2)
1.676(3)
1.485(4)
2.101(1)
2.112(3)
2.107(2)
2.096(2)
1.718(5)
1.719(6)
1.355(7)
2.102(3)
1.697(10)
1.726(9)
1.35(1)
2.118(1)
1.714(4)
1.710(4)
1.358(5)
2.100(2)
1.693(7)
1.709(8)
1.37(1)
˚
Hydrogen bonding (A)
NHꢀ ꢀ ꢀO
1.946(23)
2.877(34)
–
2.072(3)
3.130(2)
–
–
–
–
–
–
2.172(7)
3.110(5)
–
NHꢀ ꢀ ꢀS
OHꢀ ꢀ ꢀO
1.695(5)
1.580(5)
0.0264
˚
Mean deviation (A) from cobaltadithiolene plane
0.005
0.0045
0.0048
0.0154
Dihedral angle (ꢁ) of Cp/cobaltadithiolene
Dihedral angle (ꢁ) of benzene/cobaltadithiolene
88.84
12.35
87.369
8.018
92.654
15.982
95.038
2.845
90.713
–
a
Ref. [8a].
b
Data of one of two independent molecules.
˚
bondings (ca. 2.02–2.08 A) [6a]. In addition, the NHꢀ ꢀ ꢀS
hydrogen bonding has also been reported in some
complexes with bulky thiolato ligands; (Me2NHCH2-
NHTs)Co{S2C2(COOMe)2}]. The sulfonylamide group
was converted to amino group (–NH2) by an acid hydroly-
sis, or was converted to the N-metylamide group
(–N(Me)Ts) by a methylation in a basic aqueous solution.
The base hydrolysis of COOMe group in complex 1 pro-
duced the cobalt dithiolene complex with carboxylic acid.
Although a nitrogen group-substituted Cp ligand is gener-
ally difficult to synthesize, we could obtain some nitrogen
group-substituted Cp cobalt dithiolene complexes by the
imido-migration [8] and by the conversion of the sulfonyla-
mide group in complex 1.
˚
CH2NHMe2)[Pd(SC6F5)4] (3.256(6) A) [22], (Me3NCH2-
˚
CONH2)2[Co(SPh)4] (3.316(3)–3.453(3) A) [23], and
[Mo(O)(S-o-C6H4CONHMe)]ꢁ (2.97–3.03 A) [24]. Fur-
˚
thermore, complex 6 has OHꢀ ꢀ ꢀO (carbonyl oxygen) inter-
˚
molecular hydrogen bondings of 1.580(5) and 1.695(5) A in
COOH moiety between two molecules, and two molecules
were assembling each other like a typical carboxylic acid
(Fig. 3b). The TTF compounds having carboxylic acid
were also reported, and the structure of the carboxylic acid
dimer has been observed [25].
3. Experimental section
2.4. Conclusion
3.1. General remarks
In this work, we found interesting p–p interactions: the
intramolecular p–p interaction between benzene ring and
cobaltadithiolene ring in complexes 5 and 6, the intermo-
lecular p–p interactions between two benzene rings, and
between two cobaltadithiolene rings in complex 5. These
results indicate one of remarkable features of aromatic
metalladithiolene rings. We have reported electrophilic
and radical substitution reactions of metalladithiolene ring
due to its aromaticity [26]. Moreover, some intermolecular
hydrogen bondings were observed in the NHꢀ ꢀ ꢀO and
NHꢀ ꢀ ꢀS moieties of complexes 4 and 7, and in the OHꢀ ꢀ ꢀO
moiety of complex 6. These p–p interactions and the hydro-
gen bondings formed a molecular stacking and a molecular
assembling. Interestingly, the only complex 5 which does
not have a strong hydrogen bonding, showed both intra-
molecular and intermolecular interactions between aro-
matic rings. In this case, we assume that the hydrogen
bonging interferes with the p–p stacking of aromatic rings.
The products in this work were obtained by the
hydrolysis of the cobalt dithiolene complex (1) with the sul-
fonyamide-substituted cyclopentadienyl ligand [(C5H4-
All reactions were carried out under argon atmosphere
by means of standard Schlenk techniques. Organic solvents
were dried by known procedures and distilled before use.
TsOH Æ H2O, NaOH and Me2SO4 were obtained from
Wako Pure Chemical Industries, Ltd. and these were used
without further treatment. Complexes 1 and 7 were pre-
pared by literature methods [8a]. Silica gel (Wakogel C-
300) was obtained from Wako Pure Chemical Industries,
Ltd. Mass and IR spectra were recorded on a JEOL
JMS-D300 and Shimadzu model FT-IR 8600PC, respec-
tively. NMR spectra were measured with a JEOL LA500
spectrometer. UV–Vis were recorded on Hitachi model
UV-2500PC. Elemental Analyses were determined by using
a Shimadzu PE2400-II instrument. Melting points were
measured by Yanaco model Micro melting point
apparatus.
3.2. Reaction of complex 1 in acidic solution
A solution of complex 1 (100 mg, 0.2 mmol) and TsO-
H Æ H2O (380 mg, 2.0 mmol) in toluene (40 mL) was refluxed

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M. Nomura, M. Kajitani / Journal of Organometallic Chemistry 691 (2006) 2691–2700
for 24 h. The reaction mixture was extracted by CH2Cl2/
H2O, and the organic layer was dried with MgSO4. After
the organic solvent was removed under reduced pressure,
the residue was separated by a column chromatography (sil-
ica-gel, eluent = dichloromethane). The purple products
noted below were obtained: [(C5H4-NH2)Co{S2C2(COO-
Me)(H)}] (2, 3 mg, 0.012 mmol, 6% yield), [(C5H4-
NHTs)Co(S2C2H2)] (3, a trace amount) and [(C5H4-
NHTs)Co{S2C2(COOMe)(H)}] (4, 23 mg, 0.052 mmol,
26% yield). Complex 4 was further purified by recrystalliza-
tion from CH2Cl2/n-hexane.
further purified by recrystallization from CH2Cl2/n-hexane.
Complex 1 was recovered in 32% yield.
[{C5H4-N(Me)Ts}Co{S2 C2(COOMe)2}] (5). M.p. 137–
138 ꢁC. Mass (EI+, 1.3 kV) m/z (rel. intensity) 513 (M+,
100), 371 ðfC5H4-NðMeÞTsgCoSþ; 13Þ, 356 ððC5H4-NTsÞ-
2
CoSþ; 47Þ, 91 (C6H4Me+, 88), 59 (Co+, 43). 1H NMR
2
(500 MHz, CDCl3, vs. TMS) d 7.24 (d, J = 8.24 Hz, 2H,
C6H4), 6.98 (d, J = 8.24 Hz, 2H, C6H4), 5.72 (t,
J = 2.67 Hz, 2H, Cp), 5.13 (t, J = 2.67 Hz, 2H, Cp), 3.88
(s, 6H, OMe), 3.23 (s, 3H, NMe), 2.25 (s, 3H, Me). 13C
NMR (125 MHz, CDCl3, vs. TMS) d 165.1 (C@O), 159.0
(dithiolene carbon), 145.1, 129.6, 129.5, 127.0 (benzene car-
bon), 114.0, 76.0, 71.1 (Cp), 52.9 (OMe), 37.9 (NMe), 21.3
(Me). UV–Vis (CH2Cl2) kmax (e) 571 (6900), 367 (4100), 292
(18000). IR (KBr disk) 1707, 1474, 1242, 1165 cmꢁ1. Anal.
Calc. for C18H18N1O6S3Co1: C, 44.44; H, 3.93; N, 2.73.
Found: C, 44.19; H, 3.83; N, 2.51%.
[(C5H4-NH2)Co{S2C2(COOMe)(H)}] (2). Mass (EI+,
70 eV) m/z (rel. intensity) 287 (M+, 100), 203
ððC5H4-NH2ÞCoSþ; 69:9Þ, 139 ((C5H4-NH2)Co+, 12.7), 80
2
ðC5H4-NHþ; 53:4Þ. 1H NMR (500 MHz, CDCl3, vs.
2
TMS) d 8.98 (s, 1H, dithiolene-H), 5.33 (t, J = 2.01 Hz,
2H, Cp), 5.04 (t, J = 2.01 Hz, 2H, Cp), 4.71 (broad, 2H,
NH2), 3.83 (s, 3H, OMe). HR-Mass (EI+) m/z: Anal. Calc.
for C9H10N1O2S2Co1: 286.9485. Found: 286.9487.
[(C5H4-NHTs)Co(S2 C2H2)] (3). Mass (EI+, 70 eV) m/z
(rel. intensity) 383 (M+, 70.7), 91 (C6H4Me+, 100). 1H
NMR (500 MHz, CDCl3, vs. TMS) d 8.46 (s, 2H, dithio-
lene-H), 7.44 (d, J = 8.22 Hz, 2H, C6H4), 6.98 (d,
J = 8.22 Hz, 2H, C6H4), 5.47 (t, J = 2.05 Hz, 2H, Cp),
4.99 (t, J = 2.05 Hz, 2H, Cp), 2.32 (s, 3H, Me). HR-Mass
(EI+) m/z. Anal. Calc. for C14H14N1O2S3Co1: 382.9519.
Found: 382.9515.
[{C5H4-N(Me)Ts}Co{S2C2(COOMe)(COOH)}]
(6).
M.p. 176–177 ꢁC (dec.). Mass (EI+, 70 eV) m/z (rel. inten-
sity) 499 (M+, 3.0), 455 (M+ꢁCO2, 6.9), 249
(C5H5NMeTs+, 22.4), 155 (Ts+, 14.3), 94 (C5H5NMe+,
1
100), 91 (C6H4Me+, 89.8). H NMR (500 MHz, CDCl3,
vs. TMS) d 7.25 (d, J = 8.41 Hz, 2H, C6H4), 6.96 (d,
J = 8.41 Hz, 2H, C6H4), 5.76 (t, J = 2.30 Hz, 2H, Cp),
5.17 (t, J = 2.30 Hz, 2H, Cp), 3.99 (s, 6H, OMe), 3.23 (s,
3H, NMe), 2.26 (s, 3H, Me). 13C NMR (125 MHz, CDCl3,
vs. TMS) d 166.7 (C@O), 156.3 (dithiolene carbon), 145.1,
129.7, 129.5, 127.1 (benzene carbon), 114.6, 76.9, 71.0 (Cp),
53.9 (OMe), 38.0 (NMe), 21.4 (Me). UV–Vis (CH2Cl2) kmax
(e) 566 (6200), 402 (4200), 384 (4200), 297 (20000). IR (KBr
disk) 1717, 1670, 1474, 1254, 1173 cmꢁ1. Anal. Calc. for
C18H18N1O6S3Co1: C, 43.28; H, 3.63; N, 2.80; S, 19.26.
Found: C, 43.47; H, 3.50; N, 2.79; S, 19.17%.
[(C5H4-NHTs)Co{S2C2(COOMe)(H)}] (4). M.p. 229–
230 ꢁC. Mass (EI+, 70 eV) m/z (rel. intensity) 441 (M+,
100), 357 ððC5H4-NHTsÞCoSþ; 3:3Þ, 155 (Ts+, 22.5), 91
2
1
(C6H4Me+, 74.1). H NMR (500 MHz, CDCl3, vs. TMS)
d 9.11 (s, 1H, dithiolene-H), 7.37 (d, J = 8.50 Hz, 2H,
C6H4), 6.90 (d, J = 8.50 Hz, 2H, C6H4), 5.63 (t,
J = 2.05 Hz, 2H, Cp), 5.04 (t, J = 2.05 Hz, 2H, Cp), 3.87
(s, 3H, OMe), 2.25 (s, 3H, Me). UV–Vis (CH2Cl2) kmax
(e) 575 (6500), 354 (4000), 288 (16000). IR (KBr disk)
3157, 1676, 1506, 1356, 1281, 1165, 862 cmꢁ1. Anal. Calc.
for C16H16N1O4S3Co1: C, 43.53; H, 3.65; N, 3.17. Found:
C, 43.80; H, 3.71; N, 3.32%.
3.4. X-ray diffraction study
Single crystals of complexes 4–7 were obtained by
recrystallization from the dichloromethane solutions and
then vapor diffusion of n-hexane into those solutions. Each
measurement was made on a Rigaku MERCURY diffrac-
tometer with graphite-monochromated Mo Ka radiation.
The data were corrected for Lorentz and polarization
effects. Each structure was solved by direct methods and
expanded using Fourier techniques. The non-hydrogen
atoms were refined anisotropically. Hydrogen atoms were
refined using the riding model. All the calculations were
carried out using the Crystal Structure crystallographic
software package. Crystallographic data of complexes 4–
7 are summarized in Table 2.
3.3. Reaction of complex 1 in basic solution
Complex 1 (100 mg, 0.2 mmol) was added into a 20 mL
aqueous solution containing NaOH (160 mg, 4.0 mmol).
After the complex was dissolved, Me2SO4 (3.78 mL,
40 mmol) was added into this solution. The reaction mixture
was stirred at room temperature for 30 min, and then a pur-
ple precipitation was formed. The reaction mixture was
extracted by CH2Cl2/H2O, and the organic layer was dried
with MgSO4. After the organic solvent was removed under
reduced pressure, the residue was separated by a silica-gel
column chromatography. The products, [{C5H4-N(Me)Ts}-
Co{S2C2(COOMe)2}] (5, eluent = dichloromethane) and
[{C5H4-N(Me)Ts}Co{S2C2(COOMe)(COOH)}] (6, eluent =
acetone/methanol = 1:1 (v/v)), were obtained as purple
solids in 17% (17 mg, 0.034 mmol) and 48% (48 mg,
0.096 mmol) yields, respectively. Complexes 5 and 6 were
4. Supplementary material
Crystallographic data (excluding structure factors) for
the structures in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary
publication nos. CCDC 282968 (4), 282969 (5), 282970 (6)
and 282971 (7). Copies of the data can be obtained, free

M. Nomura, M. Kajitani / Journal of Organometallic Chemistry 691 (2006) 2691–2700
2699
Table 2
Crystallographic data of complexes 4–7
4
5
6
7
Formula
C16H16NO4S3Co
441.42
Purple
C19H20NO6S3Co
513.50
Purple
C18H18NO6S3Co
499.46
Purple
C12H14NO6S3Co
423.36
Violet
Formula weight/g Æ molꢁ1
Crystal color
Crystal habit
Block
Block
Block
Block
Crystal size (mm)
Crystal system
Space group
0.12 · 0.10 · 0.10
Triclinic
P-1(#2)
8.2039(5)
8.2667(5)
13.7612(10)
90.945(3)
99.903(3)
91.572(3)
918.81(10)
2
0.12 · 0.10 · 0.10
Monoclinic
P21/a(#14)
10.698(2)
22.285(3)
18.117(3)
0.09 · 0.06 · 0.03
Monoclinic
P21(#4)
12.0859(9)
14.0984(7)
13.1486(10)
0.15 · 0.10 · 0.05
Monoclinic
P21/c(#14)
11.2644(8)
10.4810(7)
14.5621(11)
˚
a (A)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
91.4391(5)
113.9469(8)
95.2284(11)
3
˚
V (A )
4317.7(11)
8
1.543
11.19
296
2047.6(2)
4
1.620
11.80
296
1712.1(2)
4
1.642
13.94
296
Z
Dcalc (g Æ cmꢁ3
)
1.595
12.95
296
l (Mo Ka)/cmꢁ1
T (K)
2 hmax/ꢁ
Unique data (Rint
No. of observations
No. of variables
55.0
3744 (0.014)
3061
55.0
9832 (0.033)
5294
55.0
6752 (0.026)
3971
55.0
3911 (0.043)
1596
)
242
581
559
222
R1, wR2 (I > 3.00 r(I))
Goodness-of-fit on F2
Largest difference peak and hole (e A
0.033, 0.044
0.898
0.43, ꢁ0.42
0.036, 0.050
1.193
0.42, ꢁ0.34
0.036, 0.047
1.014
0.53, ꢁ0.29
0.035, 0.031
1.472
0.35, ꢁ0.29
ꢁ3
˚
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