Coordination modes of 2-mercapto-1,3-benzothiazolate in gallium and indium complexes

Article abstract of DOI:10.1080/00958972.2017.1313976

2-Mercapto-1,3-benzothiazole (mbztH) may act as a chelating or bridging ligand. In this study, reactions of mbztH with Me₃Ga and Me₃In were examined. The products were characterized by NMR spectroscopy, elemental analyses, melting point, and molecular weight determinations. Formation of mononuclear chelating complexes Me₂M(mbzt) (M?=?Ga, In) was observed in solutions. Crystallization of Me₂M(mbzt) yielded uncommon non-symmetrical dinuclear complexes Me₄M₂(mbzt)₂, in which one metal is bonded to two sulfurs and the other to two nitrogens.

Full text of DOI:10.1080/00958972.2017.1313976

Journal of Coordination Chemistry
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Coordination modes of 2-mercapto-1,3-
benzothiazolate in gallium and indium complexes
Dariusz Basiak, Wanda Ziemkowska, Paweł Socha, Łukasz Dobrzycki,
Zbigniew Ochal & Edyta Pindelska
To cite this article: Dariusz Basiak, Wanda Ziemkowska, Paweł Socha, Łukasz Dobrzycki,
Zbigniew Ochal & Edyta Pindelska (2017): Coordination modes of 2-mercapto-1,3-
benzothiazolate in gallium and indium complexes, Journal of Coordination Chemistry, DOI:
10.1080/00958972.2017.1313976
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Date: 02 April 2017, At: 05:45

Publisher: Taylor & Francis
Journal: Journal of Coordination Chemistry
DOI: http://dx.doi.org/10.1080/00958972.2017.1313976
Coordination modes of 2-mercapto-1,3-benzothiazolate in gallium and
indium complexes
DARIUSZ BASIAK*†, WANDA ZIEMKOWSKA†, PAWEŁ SOCHA‡, ŁUKASZ DOBRZYCKI‡,
ZBIGNIEW OCHAL† and EDYTA PINDELSKA§
†Warsaw University of Technology, Faculty of Chemistry, Noakowskiego 3, 00-664 Warsaw, Poland
‡
University of Warsaw, Department of Chemistry, Pasteura 1, 02-093 Warsaw, Poland
§
Medical University of Warsaw, Faculty of Pharmacy, Department of Inorganic and Analytical Chemistry,
Banacha 1, 02-093 Warsaw, Poland
2
-Mercapto-1,3-benzothiazole (mbztH) may act as a chelating or bridging ligand. In this
study, reactions of mbztH with Me Ga and Me In were examined. The products were
characterized by NMR spectroscopy, elemental analyses, melting point and molecular weight
determinations. Formation of mononuclear chelating complexes Me M(mbzt) (M = Ga, In)
was observed in solutions. Crystallization of Me M(mbzt) yielded uncommon non-
, in which one metal is bonded to two sulfurs
3
3
2
2
symmetrical dinuclear complexes Me
and the other to two nitrogens.
4 2 2
M (mbzt)
Keywords: Gallium; Indium; Thiazoles; 2-Mercapto-1,3-benzothiazole; Chelating ligands;
Bridging ligands
1
. Introduction
Functionalized thiazoles are potential multifunctional ligands in the synthesis of metal
complexes. 2-Mercapto-1,3-benzothiazole (mbztH) containing two sulfurs and one nitrogen
exists in tautomeric forms (scheme 1) that allow it to act as monodentate S- or N-ligands.
Examples of such complexes include gold (Ph
platinium Pt(mbzt) (PTA) and palladium Pd(mbzt)
phosphaadamantane) [3], tin [(C Sn(mbzt)] [4] and mercury Hg(mbzt)
and the antimony complex Ph Sb(mbzt) [6] as an N-ligand. Reports of mbzt as a chelating
3
P)Au(mbzt) [1], zinc [Zn(mbzt)
(PTA) (where PTA = 1,3,5-triaza-7-
[5] as S-ligands
2 2
(py) ] [2],
2
2
2
2
6
H
5
)
3
2
2
N,S-ligand include iridium [7], tin [8, 9], ruthenium [10], chromium [11], europium and
erbium [12] or uranium, neodymium and cesium [13, 14] complexes. The bridging mode of
*
Corresponding author. Email: dbasiak@ch.pw.edu.pl
1

the mbzt ligand was observed in a rhodium compound [15]. Although there are numerous
examples of transition metal complexes containing mbzt ligands, similar complexes of main
group metals, with the exception of tin compounds, are unknown.
In our previous work, we examined products of reactions between aluminum trialkyls
and 1-(1,3-benzothiazol-2-ylsulfanyl)propan-2-ol which can act as monodentate, bidentate or
bridging ligand depending on the steric hindrance of the alkyl group [16]. Herein, we report
3 3
gallium and indium complexes obtained in reactions of Me Ga and Me In with mbztH. We
have assumed there are numerous possibilities of coordination patterns of mbzt with gallium
and indium ions, because of various coordination modes of mbzt ligands in transition metal
complexes and structures of group 13 metals with other multifunctional ligands like
2
-mercapto-1-methyl-imidazole [17] and 2-mercaptobenzoxazole [18].
2
. Results and discussion
Treatment of mbztH with one equivalent of Me
crystallization from solution at -25 °C yielded solids of Me
2)] (scheme 2). Products of reaction were characterized by NMR spectroscopy, elemental
analyses, melting point and molecular weight determinations.
3
M (M = Ga, In) in Et
2
O followed by
4
M
2
(mbzt) [M = Ga (1); M = In
2
(
Isolation of 1 in a crystalline form allowed determination of its molecular and crystal
structure. The molecular structure was determined on the basis of an X-ray diffraction study
and is shown in figure 1. Data collection parameters and structure analysis are listed in
table 1. In a unit cell, crystals of 1 contain two kinds of molecules (A and B) differing slightly
in bond lengths and angles. X-ray diffraction analysis of 1 revealed a dinuclear structure with
an 8-membered Ga
2 2 2 2
S N C central ring and two methyl groups connected to both gallium
ions. The central ring is not centrosymmetric: one gallium forms two M-S bonds and the other
–
two M-N bonds. Lengths of the Ga(1A)-N(1A) and Ga(1A)-N(2A) bonds are very similar,
.047(2) and 2.052(2) Å, respectively. The same applies to Ga(2A)-S(2A) and Ga(2A)-S(4A)
2
(2.401(1) and 2.409(1) Å) bond lengths, and C(7A)–S(2A)–Ga(2A) 97.2(1)° and C(14A)–
S(4A)–Ga(2A) 97.2(1)° bond angles. This proves the electron delocalization within N-C-S
part of the ligand and the mixed single-double character of metal-heteroatom bonds. The mbzt
ligands play a bridging role between gallium ions. Formation of the coordination bonds
between sulfur of the heterocyclic rings [S(1A) and S(3A)] and metallic centers was not
observed. All atoms of the fused aromatic and heterocyclic rings are positioned in one plane,
which is evidenced by the torsional angle values S(3A)–C(8A)–C(13A)–C(12A) 179.1 (2)°
and S(1A)–C(1A)–C(6A)–C(5A) 179.9(2)°.

X-ray diffraction study of the indium compound 2 indicated that its molecular
structure is analogous to the gallium complex 1, however the crystal structure was
insufficiently solved [R
1 2 o o
= 0.1258, wR = 0.3056 for 6447 reflections with I > 2 σ(I )]
because of a highly disordered crystal lattice.
Compounds 1 and 2 are rare examples of complexes containing metallic centers
bonded only with one kind of donor atom, X or Y of bifunctional XY ligands. There are
numerous examples of centrosymmetric complexes of group 13 metal trialkyls, in which each
metal atom is bonded to X and Y atoms of the ligand [19], while we have found only two
reports on compounds with metal centers similar to these in 1 and 2: aluminum and gallium
2-mercaptobenzoxazolates [18] and aluminum pyridine-2-thiolates [20].
A search for tailored porous materials prompted us to examine the molecular packing
in a crystal structure of 1. The X-ray measurements showed closely packed laminar crystal
structure with layer distances along the a and c axes estimated at 3 Å (for a view of the crystal
packing along a, see figure 2).
NMR analyses of 1 and 2 revealed a difference between the solid state structures and
structures in solution. Contrary to the X-ray diffraction analyses showing an unequivalence of
1
Me
3
M groups, in the H NMR spectra there is only one singlet of methyl group protons at
0
.11 and 0.17 ppm for gallium and indium, respectively. A similar case was reported
previously for the reaction of trimethylaluminum with pyridine-2-thiol. In the crystal structure
of obtained product, Me Al (PyS) , a non-symmetric ring of the same type was observed.
4
2
2
NMR experiments were carried out in the wide temperature range, showing the
transformation of the methyl region of the spectra from one singlet at 45 °C to two separated
singlets at -35 °C [20]. This inspired us to conduct analogous low-temperature NMR
experiment, however, we have not observed the splitting of methyl group assigned signal even
at -50 °C. The only visible change was the decreasing of signal intensity due to lowering of
solubility. Based on this result we propose that products of examined reaction form different
structures in solution (named 1a and 2a). According to literature, there are two possibilities,
both complying with the obtained NMR spectrum. One of them could be mononuclear
complex Me
metal. There are several reports on group 13 metal complexes forming this type of
coordination ring. Examples could be aluminum complex obtained in the reaction of Me Al
with a bulky thiourea ligand [21], dimethylthallium complex of thiosemicarbazone derivative
22] or interesting dinuclear complexes of aluminum or gallium containing both five- and
four-membered rings [23, 24]. The other possibility could be a dinuclear complex containing
2
M(mbzt) with a four-membered ring containing sulfur, carbon, nitrogen and
3
[

four-membered ring M
bonds. This variant has not been described yet for S,N-ligands, however it is possible for
similar O,N-ligands. An example could be the product of the reaction between Me Al and
-methyl-1-(phenylamino)propan-2-ol [25]. To determine the correct type of structure we
2 2
S with nitrogens not involved in the formation of any additional
3
2
conducted molecular mass measurement using the cryoscopic method in benzene. Obtained
results, 297 and 320 g/mol for 1a and 2a, respectively (calculated 266.04 and 311.13 g/mol),
indicate mononuclear Me
is a chelating ligand.
2
M(mbzt). In the case of this structure 2-mercapto-1,3-benzothiazole
3
3
. Experimental
.1. General procedures
All manipulations were carried out using standard Schlenk technique under argon. Solvents
were distilled over the blue benzophenone-potassium complex. Trimethylgallium (99+%) was
purchased from Strem Chemicals. Trimethylindium was synthesized from anhydrous indium
chloride and methylmagnesium iodide in diethyl ether according to literature procedure [26].
1
13
H and C NMR spectra were obtained on a Mercury-400BB spectrometer. Chemical shifts
1
3
were referenced to the residual proton signals of CDCl
3
(7.26 ppm). C NMR spectra were
, 77.20 ppm). Elemental analyses were
3
1
3
acquired at 100.60 MHz (standard: chloroform CDCl
obtained on a Perkin Elmer 2400 analyzer. Molecular weights were measured by the
cryoscopic method in benzene solutions.
3
.2. Synthesis of 2-mercapto-1,3-benzothiazole (mbztH)
2
-Mercapto-1,3-benzothiazole was obtained using modified literature procedure [27]. Carbon
disulfide (11.4 g, 0.15 mol) and solution of KOH (6.7 g, 0.12 mol) in water (50 ml) were
added to a solution of 2-aminothiophenol (12.52 g, 0.1 mol) in ethanol (200 ml). The mixture
2
was heated at reflux for 5 h. After cooling, ethanol and CS excess were removed on a rotary
evaporator and the residue was dissolved in water (100 ml). Obtained solution was acidified
with acetic acid, which resulted in precipitation of a pale-yellowish solid. The precipitate was
filtered off, washed with water until neutral, dried and crystallized in ethanol. Yield: 12.4 g
1
(
74 wt%). H NMR (CDCl
3
) δ: 12.13 (broad, 1H, SH) 7.47 (d, J = 7.6 Hz, 1H, Harom), 7.36
1
3
(
m, 2H, Harom), 7.28 (m, 1H, Harom) ppm; C NMR (CDCl3) δ: 190.70 (CS
29.92, 127.20, 124.68, 121.32, 112.33 (Carom) ppm; Mp = 178-180 °C.
2
N), 140.23,
1

3
.3. General procedure for synthesis of 1 and 2
3
Me
3
M (3 cm , 1M solution in Et
2
O) (M = Ga, In) was slowly added to suspension of mbztH
-3
3
(
0.5 g, 3×10 mol) in Et
2
O (10 cm ) at -78 °C. The reaction mixture was slowly warmed to
room temperature. Evolution of gases and precipitation of solid products was observed. The
solids were filtered off, washed with Et O and vacuum dried. Crystals of 1 and 2 were
obtained from solution in n-C Cl mixture at -25 °C. Isolated yields: 0.326 g
41 wt%) and 0.459 g (49 wt%) for 1 and 2, respectively.
2
6
H
14 / CH
2
2
(
3
.4. Charaterization of Me
2
Ga(mbzt) (1a)
1
H NMR (CDCl
3
) δ: 7.72 (m, 2H, Harom), 7.44 (t, J = 8.0 Hz, 1H, Harom), 7.36 (t, J = 8.0 Hz,
1
3
1
H, Harom), 0.11 (s, 6H, Ga(CH
3
)
2
) ppm. C NMR (CDCl
) ppm. Molecular weight Found: 257;
Ga(mbzt): 266 g mol . Anal. Found: C, 40.24, H, 3.98; Calcd. for
: C, 40.60; H, 3.76 (wt%). Mp.: 115 °C.
3 2
) δ: 182.42 (CS N), 147.80, 134.53,
1
26.38, 124.42, 121.03, 117.34 (Carom), -2.83 (GaCH
3
−
1
Calcd for Me
2
C
18
H20Ga
2
N
2
S
4
3
.5. Characterization of Me
2
In(mbzt) (2a)
1
H NMR (CDCl
H, Harom), 7.33 (m, 1H, Harom), 0.17 (s, 6H, In(CH
CS N), 149.60, 135.96, 126.40, 124.45, 121.20, 117.86 (Carom), -2.24 (InCH
Molecular weight Found: 320; Calcd for Me
H, 3.01; Calcd. for C18 : C, 34.76; H, 3.21 (wt%). Mp.: 202-203 °C.
3
) δ: 7.75 (d, J = 8.0 Hz, 1H, Harom), 7.69 (d, J = 8.8 Hz, 1H, Harom), 7.42 (m,
1
3
1
3
)
2
) ppm. C NMR (CDCl
3
) δ: 181.03
) ppm.
In(mbzt): 311 g mol . Anal. Found: C, 34.38;
(
2
3
−
1
2
2 2 4
H20In N S
3
.6. Crystallographic data
The X-ray measurement of 1 was performed at 100(2) K on a Bruker D8 Venture Photon100
diffractometer equipped with a TRIUMPH monochromator and a MoKα fine focus sealed
tube (λ = 0.71073 Å). A total of 990 frames were collected with Bruker APEX2 program [28].
The frames were integrated with the Bruker SAINT software package [29] using a narrow-
frame algorithm. The total exposure time was 1.65 h. The frames were integrated with the
Bruker SAINT software package using a narrow-frame algorithm. Data were corrected for
absorption effects using the multi-scan method (SADABS) [30]. The structure was solved and
refined using SHELXTL Software Package [31].
All non-H atoms were refined anisotropically. All hydrogens were placed in calculated
positions and refined within the riding model. The temperature factors of these hydrogens

were not refined and were set to be either 1.2 or 1.5 times larger than Ueq of the corresponding
heavy atom. The atomic scattering factors were taken from the International Tables [32].
4
. Conclusion
Reactions of mbztH with Me
complexes Me M(mbzt) (M = Ga, In). Crystallization of Me
3
Ga and Me
3
In led to formation of mononuclear chelating
M(mbzt) yielded uncommon
2
2
non-symmetrical dinuclear complexes, in which one metal is bonded to two sulfurs and the
other to two nitrogens.
Appendix A. Supplementary material
CCDC 1501077 (1) contains the supplementary crystallographic data for this paper. These data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; Fax: (+44) 1223-336-033;
or E-mail: deposit@ccdc.cam.ac.uk.
Acknowledgements
We thank the Warsaw University of Technology (Warsaw, Poland) for financial support. The
X-ray structure was determined in the Advanced Crystal Engineering Laboratory (aceLAB) at
the Chemistry Department of the University of Warsaw (Warsaw, Poland).
References
[1]
K.N. Kouroulis, S.K. Hadjikakou, N. Kourkoumelis, M. Kubicki, L. Male, M.
Hursthouse, S. Skoulika, A.K. Metsios, V.Y. Tyurin, A.V. Dolganov, E.R. Milaevag,
N. Hadjiliadis. Dalton Trans., 10446 (2009).
[
2]
3]
R. Baggio, M.T. Garland, M. Perec. J. Chem. Soc., Dalton Trans., 3367 (1993).
E. Guerrero, S. Miranda, S. Lüttenberg, N. Fröhlich, J.-M. Koenen, F. Mohr, E.
Cerrada, M. Laguna, A. Mendia. Inorg. Chem., 52, 6635 (2013).
[
[
4]
5]
M.N. Xanthopoulou, S.K. Hadjikakou, N. Hadjiliadis, M. Kubicki, S. Skoulika, T.
Bakas, M. Baril, I.S. Butler. Inorg. Chem., 46, 1187 (2007).
[
N.A. Bell, S.J. Coles, C.P. Constable, D.E. Hibbs, M.B. Hursthouse, R. Mansor, E.S.
Raper, C. Sammon. Inorg. Chim. Acta, 323, 69 (2001).
[
6]
7]
P. Raj, A.K. Aggarwal, N. Misra. Polyhedron, 8, 581 (1989).
[
M.A. Ciriano, J.A. Lopez, L.A. Oro, J.J. Perez-Torrente. Organometallics, 14, 4764
(1995).

[8]
D.B. Shpakovsky, C.N. Banti, G. Beaulieu-Houle, N. Kourkoumelis, M. Manoli, M.J.
Manos, A.J. Tasiopoulos, S.K. Hadjikakou, E.R. Milaeva K. Charalabopoulos, T.
Bakas, I.S. Butler, N. Hadjiliadis. Dalton Trans., 14568 (2012).
[
[
9]
J. Susperregui, M. Bayle, J.M. Léger, G. Déléris. J. Organomet. Chem., 556, 105
(1998).
10] P. Appelta, F.D. Fagundesa, G. Facchinb, M.G. Kramerc, D.F. Backd, M.A.A.
Cunhae, B. Sandrinof, K. Wohnrathf, M.P. de Araujo. Inorg. Chim. Acta, 436, 152
(2015).
[
11] L.Y. Goh, Z. Weng, W.K. Leong, J.J. Vittal. J. Am. Chem. Soc., 124, 8804 (2002).
12] M. Katkowa, A.V. Borisov, G.K. Fukin, E.V. Baranov, A.S. Averyushkin, A.G.
Viyukhnovsky, M.N. Bochkarev. Inorg. Chim. Acta, 359, 4289 (2006).
13] M. Roger, L. Belkhiri, T. Arliguie, P. Thuéry, A. Boucekkine, M. Ephritikhine.
Organometallics, 27, 33 (2008).
[
[
[
14] M. Roger, T. Arliguie, P. Thuery, M. Ephritikhine. Inorg. Chem., 47, 3863 (2008).
15] M.A. Ciriano, J.J. Perez-Torrente, L.A. Oro, A. Tiripicchio, M. Tiripicchio-Camellini.
J. Chem. Soc., Dalton Trans., 255 (1991).
[
[16] D. Basiak, Z. Ochal, I. Justyniak, W. Ziemkowska. Polyhedron, 102, 705 (2015).
[17] D.A. Cooper, S.J. Rettig, A. Storr, J. Trotter. Can. J. Chem., 64, 1643 (1986).
[18] W. Ziemkowska, J. Skałkowska, Z. Ochal, M.K. Cyrański, Ł. Dobrzycki, I. Madura, J.
Zachara. J. Organomet. Chem., 776, 1 (2015).
[
19] For examples see: (a) J.M. Klerks, R. Van Vliet, G. Van Koten, K. Vrieze. J.
Organomet. Chem., 214, 1 (1981). (b) U. Dembowski, M. Noltemeyer, J.W. Gilje,
H.W. Roesky. Chem. Ber., 124, 1917 (1991). (c) J. Lewiński, I. Justyniak, J. Zachara,
E. Tratkiewicz. Organometallics, 22, 4151 (2003). (d) A. Maisse-Francois, L. Azor,
A.-L. Schmitt, A. Coquel, L. Brelot, R. Welter, S. Bellemin-Laponnaz, S. Dagorne. J.
Organomet. Chem., 696, 4248 (2012).
[20] R. Kumar, V.S.J. de Mel, J.P. Oliver. Organometallics, 8, 2488 (1989).
[21] M.P. Coles, D.C. Swenson, R.F. Jordan. Organometallics, 17, 4042 (1998).
[22] J.S. Casas, M.V. Castano, M.C. Cifuentes, A. Sanchez, J. Sordo. Polyhedron, 21, 1651
(2002).
[
[
[
23] C. Paek, S.O. Kang, J. Ko. Organometallics, 16, 2110 (1997).
24] Y. Kang, N. Yang, S.O. Kang, J. Ko. Organometallics, 16, 5522 (1997).
25] S. Yoon, S.H. Kim, J. Heo, Y. Kim. Inorg. Chem. Commun., 29, 157 (2013).

[
26] D.F. Foster, S.A. Rushworth, D.J. Cole-Hamilton, R. Cafferty, J. Harrison, P. Parkes.
J. Chem. Soc., Dalton Trans., 7 (1988).
[27] M. Rafeeq, C.V.R. Reddy, P.K. Dubey. Phosphorus, Sulfur Silicon Relat. Elem., 190,
1
857 (2015).
[28] APEX2, Bruker AXS Inc., Madison, Wisconsin, USA (2013).
[29] SAINT, Bruker AXS Inc., Madison, Wisconsin, USA (2013).
[30] SADABS, Bruker AXS Inc., Madison, Wisconsin, USA (2012).
[31] (a) G.M. Sheldrick. Acta Crystallogr., A46, 467 (1990). (b) G.M. Sheldrick. Acta
Cryst., A64, 112 (2008).
[32] International Tables for Crystallography, A.J.C. Wilson (Ed.), Kluwer: Dordrecht,
Vol. C (1992).

Table 1. Crystal data and data collection parameters for 1.
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal size (mm)
Crystal system
Space group
a (Å)
18 2 2 4
C H20Ga N S
532.04
100(2)
0.71073
0.208 × 0.246 × 0.414
Monoclinic
1
P2 /c
9.1434(12)
b (Å)
29.352(4)
c (Å)
15.732(2)
α (°)
90
β (°)
90.241(4)
γ (°)
90
3
V (Å )
4222.1(10)
3
D
calc (g/cm )
8, 1.674
-1
Absorption coefficient (mm )
F(000)
2.953
2144
θ range for data collection (°)
Index ranges
2.23 - 25.05
-10≤h≤10, -34≤k≤34, -18≤l≤18
40506
Reflections collected
Independent reflections
Data / restraints / parameters
7473 [Rint = 0.0391]
7473 / 0 / 477
1.111
2
Goodness-of-fit on F
Final R indices [I>2σ(I)]
R1 = 0.0298, wR2 = 0.0657
R1 = 0.0411, wR2 = 0.0701
0.592 and -0.345
Final R indices (all data)
-3
Max/Min of residual electron density (eÅ )