Synthesis, structure and electrochemistry of CoIILCl 2·0.5MeCN {L = [2-(methylthio)-3-phenyl-5-(pyridin-2- ylmethylene)-3,5-dihydro-4H-imidazol-4-one]}

Article abstract of DOI:10.1070/MC2004v014n03ABEH001889

The reaction of 2-(methylthio)-3-phenyl-5-(pyridin-2-ylmethylene)-3,5- dihydro-4H-imidazol-4-one (L) with CoCl₂·6H₂O in MeCN-CH₂Cl₂ results in formation of the complex CoLCl ₂·0.5MeCN, which was chara

Full text of DOI:10.1070/MC2004v014n03ABEH001889

, 2004, 14(3), 115–117
Synthesis, structure and electrochemistry of CoIILCl2·0.5MeCN
{L = [2-(methylthio)-3-phenyl-5-(pyridin-2-ylmethylene)-3,5-dihydro-
4H-imidazol-4-one]}
Alexander G. Majouga, Elena K. Beloglazkina, Sergey Z. Vatsadze,* Anna A. Moiseeva, Kim P. Butin and
Nikolai V. Zyk
Department of Chemistry, M. V. Lomonosov Moscow State University, 119992 Moscow, Russian Federation.
Fax: + 7 095 939 0290; e-mail: szv@org.chem.msu.ru
DOI: 10.1070/MC2004v014n03ABEH001889
The reaction of 2-(methylthio)-3-phenyl-5-(pyridin-2-ylmethylene)-3,5-dihydro-4H-imidazol-4-one (L) with CoCl2·6H2O in
MeCN–CH2Cl2 results in formation of the complex CoLCl2·0.5MeCN, which was characterised by single-crystal X-ray
diffraction analysis and an electrochemical study.
In the last few years, considerable attention has been paid to the
molecular systems containing 2-thiohydantoin units. Hetero-
C(14)
cyclic compounds of this type are attractive ligands because
they can coordinate metal ions via nitrogen and/or sulfur donor
atoms.1–3 They can also form supramolecular networks by
N–H···S and N–H···O hydrogen bonds.4 Some 2-thiohydantions
exhibit a wide range of pharmacological activities (anticonvul-
sant, antibacterial, antiviral and platelet aggregation inhibitory
activities).5–8
C(13)
C(15)
C(12)
C(16)
C(11)
S(1)
N(3)
O(1)
C(9)
C(8)
C(7)
C(10)
Heterocyclic compounds such as 2-thiohydantoins and their
alkylated analogues
N(2)
Co(1)
C(6)
Cl(1)
Cl(2)
C(5)
R
N
R
N
N(1)
O
S
O
S
C(4)
C(1)
R'
,
NH
N
C(2)
C(3)
which possess different endo- and exocyclic electron-donating
atoms, are interesting chelating ligands towards metal ions.1–3,9
Furthermore, the methylene carbon in the 5-position of these
compounds is nucleophilic,2 facilitating the synthesis of 5-sub-
stituted derivatives, with or without additional donor atoms. In
particular, N-3 unsubstituted 5-(pyridin-2-yl-methylene)hydantoin
in the reaction with CuCl2 forms a supramolecular complex, in
which the chelation of CuII ions by two nitrogen atoms is
accompanied by the fastening of the organic fragments by
hydrogen bonds.9
We studied the reactivity of 2-(methylthio)-3-phenyl-5-(pyri-
din-2-ylmethylene)-3,5-dihydro-4H-imidazol-4-one 1,† which
was obtained from 3-phenyl-2-thiohydantoin and 2-pyridine
carboxaldehyde, towards cobalt(II) chloride. The reaction results
in CoIILCl2·0.5MeCN adduct 2 (L = compound 1).‡
Figure 1 Molecular structure of 2 (only one of the two crystallographically
independent molecules is shown). The important bond lengths (Å) and
bond angles (°) (data for the second crystallographically independent
molecule are given in parentheses): Co(1)–N(1) 2.044(3) [Co(1A)–N(1A)
2.028(6)], Co(1)–N(2) 1.992(5) [Co(1A)–N(2A) 2.022(3)], Co(1)–Cl(2)
2.2385(15) [Co(1A)–Cl(2A) 2.2466(15)], S(1)–C(9) 1.725(4) [S(1A)-C(9A)
1.711(7)], Co(1)–Cl(1) 2.267(2) [Co(1A)–Cl(1A) 2.2646(14)]; N(2)–Co(1)–
N(1) 96.81(18) [N(2A)–Co(1A)–N(1A) 97.10(19)], N(2)–Co(1)–Cl(2)
120.18(14) [N(2A)–Co(1A)–Cl(2A) 114.53(12)], N(1)–Co(1)–Cl(2)
105.75(11) [N(1A)–Co(1A)–Cl(2A) 104.94(11)]; N(2)–Co(1)–Cl(1)
114.34(14) [N(2A)–Co(1A)–Cl(1A) 120.00(12)]; N(1)–Co(1)–Cl(1)
105.71(17) [N(1A)–Co(1A)–Cl(1A) 106.03(13)]; Cl(2)–Co(1)–Cl(1)
111.43(7) [Cl(2A)–Co(1A)–Cl(1A) 111.53(6)].
and two imine nitrogen atoms. Complexation with transition
metal ions would occur through the nitrogen and sulfur atoms.
The molecular and crystal structures of 2 were determined by
single-crystal X-ray diffraction analysis.§ The crystals suitable
for X-ray analysis were obtained by slow diffusion of diethyl
ether vapour to a MeCN–CH2Cl2 (1:1) solution of the complex.
The molecular structure of complex 2 and the atom numbering
are shown in Figure 1. The central cobalt atom is coordinated to
two nitrogen atoms of the pyridine and thiohydantoin moieties
and two chlorine atoms in a distorted tetrahedral fashion. The
sulfur atom is staying away from coordination with cobalt
(S–Co distances for both of the independent molecules are
As shown in Scheme 1, compound 1 has four potential donor
atoms: the oxygen atom of the carbonyl group, the sulfur atom
†
1 g (5.2 mmol) of 3-phenyl-2-thiohydantoin was dissolved in 14 ml of
2% KOH solution in ethanol with vigorous stirring. When the solution
became clear, 0.56 g (5.2 mmol) of 2-pyridine carboxaldehyde was added
by drops. The mixture was stirred for 12 h, after that 0.74 g (5.2 mmol)
of methyl iodide was added to the mixture. The precipitate was filtered
off and recrystallised from EtOH–DMF (3:1). The yield of 2-(methyl-
thio)-3-phenyl-5-[(Z)-pyridin-2-ylmethylene]-3,5-dihydro-4H-imidazol-
4-one was 67%. Mp 206 °C. 1H NMR ([2H6]DMSO) d: 8.69 (d, 1H,
Hα'-Py, J 8.3 Hz), 8.53 (d, 1H, Hβ-Py, J 4.4 Hz), 8.03 (t, 1H, Hγ-Py,
J 4.4 Hz), 7.46 (m, 6H, Hβ-Py, Ph), 6.88 (s, 1H, CH=), 2.70 (s, 3H,
Me). 13C NMR ([2H6]DMSO) d: 173.5, 166.7, 165.2, 151.8, 147.9, 138.1,
134.1, 127.5, 127.2, 125.2, 122.1, 121.1, 11.3. IR (KBr, n/cm–1): 1730
(C=O), 1650 (C=N), 1600 (C=C). Found (%): C, 64.77; H, 4.54; N,
14.25. Calc. for C16H13OSN3 (%): C, 65.08; H, 4.41; N, 14.24.
Ph
N
Ph
N
O
S
O
S
Ph
N
Me
Cl
Me
N
N
i, ii
iii
O
S
Co ·0.5MeCN
N Cl
‡
3 ml of acetonitrile was added to a solution of 10 mg (0.034 mmol) of
N
NH
2-(methylthio)-3-phenyl-5-[(Z)-pyridin-2-ylmethylene]-3,5-dihydro-4H-
imidazol-4-one in 2–3 ml of methylene chloride to give two phases.
After that the solution of 8 mg (0.034 mmol) of CoCl2·6H2O in 3 ml of
acetonitrile was slowly added. Crystals suitable for X-ray analysis were
obtained from the solution after diethyl ether diffusion. Yield of 2 82%.
IR (KBr, n/cm–1): 1756, 1746 (C=O), 1644 (C=N), 1594 (C=C).
1
2
Scheme 1 Reagents and conditions: i, 2-PyCHO, KOH, EtOH; ii, MeI,
EtOH; iii, CoCl2·6H2O, CH2Cl2, MeCN.
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, 2004, 14(3), 115–117
Table 1 Electrochemical oxidation (EOx) and reduction (ERed) potentials
[vs. Ag/AgCl/KCl(saturated)] of 1, 2 and CoCl2·6H2O (concentration
10–3 mol dm–3). Carbon glassy electrode, MeCN, 0.05 M Bu4NBF4.
Compound
–ERed/V EOx/V
Notes
1
1.29
1.77
1.99
1.71
2.16
Using a Pt working electrode,
oxidation peaks appear at 1.69 and
2.25 V; at an Au electrode, at 1.65
and 2.20 V.
2
0.58
1.30
1.67
1.99
1.82
2.10
At Pt or Au electrodes, the first
oxidation peak shifts to 1.52 V (Pt)
or 1.29 V (Au); the second oxidation
peak is not observed.
CoCl2·6H2O 0.84a
1.56
1.72
aOn thoroughly cleaning the electrode
surface. At the second potential scan,
the first reduction peak decreases and,
beginning with the third scan only,
one wave is observed at –1.32 V.
1.12b
bWhen the potential is scanned into
anodic site after reaching E = –1.12 V,
the peak of the oxidative desorption of
Co metal can be observed at +0.24 V.
independent layers are linked by the week interaction of the
‘CH-aromatic ring’ type because the shortest distance between
the carbon atoms of adjacent crystallographically independent
molecules [C(15) and C(16A) atoms] is 3.374 Å.11
Figure 2 Crystal structure of 2 viewed down the crystallographic a axis.
The hydrogen atoms are omitted for clarity.
In the crystal structure of 2, there is one additional acetonitrile
molecule per two crystallographically independent complex mole-
cules. Acetonitrile molecules occupy the voids between the
stacks of dimers A and B (Figure 2).
The electrochemistry of free ligand 1 and complex 2 was
studied by cyclic voltammetry (CV) in dry MeCN in the presence
of 0.05 M Bu4NBF4 as an indifferent electrolyte. The results of
redox potential measurements for 1, 2 and CoCl2·6H2O are
given in Table 1.
3.896–3.897 Å), and the methyl group bound to sulfur is closer
to the coordinated cobalt centre.
The molecules of organic ligands in the complex structure
are not planar, since phenyl rings at N(3) and five-membered
rings are tilted in respect to each other (the dihedral angles
between the corresponding planes are 88.6° and 89.3° for two
independent molecules). Thiohydantoin and pyridine rings are
practically coplanar.
The nearest intermolecular contacts found in the structure of
2 are the contacts between the chlorine atom and one of the
hydrogen atoms of the methyl group of the adjacent centro-
symmetric molecule (2.903 Å). This interaction results in
dimers associated by CH–Cl-type hydrogen bonds (the sum of
the van der Waals radii of hydrogen and chlorine atoms is
3.01 Å10). Moreover, the carbon atoms of methyl groups are
at a distance of 3.332 Å, and this distance is also shorter than
the sum of the van der Waals radii of carbon (3.70 Å10). The
above dimers form a layered crystal structure, in which the
layers of type A dimers alternate with the layers of type B
dimers (Figure 2).
The π–π interactions of aromatic rings in the crystal structure
of 2 are not found. The nearest distance between the centroids
of benzene rings (4.553 Å) is the distance between the benzene
rings of the adjacent independent molecules. This distance does
not fall into the range of those typical of π–π interactions.11
However, it is worth noting that the adjacent crystallographically
For free ligand 1, the CV curve shows three reduction peaks
and two oxidation peaks (Figure 3). For complex 2, four
peaks can be observed in the cathodic region, from which the
first (–0.58 V) probably results from the reduction of CoII, and
the potentials of the following peaks are close to the potentials
of three cathodic peaks of the free ligand. We believe that
complex 2 does not dissociate significantly into free ligand 1
and CoCl2 during the electrochemical experiments. This was
proved by the comparison of CV curves of the complex, the
free ligand and CoCl2·6H2O, which showed essential differences
in their electrochemical behaviours (Figure 3, Table 1).
This work was supported by the Russian Foundation for
Basic Research (grant nos. 03-03-32401 and 04-03-32845).
§
Crystallographic data for 2: crystals of C17H14.5N3.5OSCl2Co are dark
5 µA
green prisms, M = 445.71. Crystal size: 0.6×0.5×0.3 mm, monoclinic,
space group P21/n; unit cell dimensions a = 8.848(4), b = 11.332(4),
c = 21.332(8) Å; V = 1900.2(13) Å3, Z = 4, dcalc = 1.558 g cm–3. X-ray
diffraction of 2 measured with a Syntex P21 diffractometer at 293 K
[graphite monochromator, l(MoKα) = 0.71073 Å, w-scan with a step of
0.3°]. The structure was solved by a direct method (SHELXS-97) and
refined by the full-matrix least-square technique against F2 for all non-
hydrogen atoms (SHELXL-97). F(000) = 904. Limiting indices:
0 £ h £ 11, –13 £ k £ 5, –27 £ l £ 26; reflections collected/unique
4760/4530 [R(int) = 0.0191]; goodness-on-fit on F2 0.977; R indices [for
3283 rfls with I > 2s(I)]: R1 = 0.0421, wR2 = 0.0937; R indices (all
data): R1 = 0.0780, wR2 = 0.1053. Largest diff. peak and hole, 0.306 and
–0.324 eÅ–3, respectively.
Atomic coordinates, bond lengths, bond angles and thermal param-
eters have been deposited at the Cambridge Crystallographic Data Centre
(CCDC). These data can be obtained free of charge via www.ccdc.cam.uk/
conts/retrieving.html (or from the CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK; fax: +44 1223 336 033; or deposit@ccdc.cam.ac.uk).
Any request to the CCDC for data should quote the full literature citation
and CCDC reference number 238622. For details, see ‘Notice to Authors’,
Mendeleev Commun., Issue 1, 2004.
2.0
1.0
0.0
–1.0
–2.0
E/V
Figure 3 Cyclic voltammograms of 1 (dashed line), 2 (solid line) and
CoCl2·6H2O (dash-dot line) (MeCN, 0.05 M Bu4NBF4).
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, 2004, 14(3), 115–117
7
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L. Maneva, K. Grancharov and N. Spassovska, J. Inorg. Biochem.,
2002, 89, 203.
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Received: 15th January 2004; Com. 04/2215
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