Synthesis and characterization of N,N-methylphenylthiocarbamoylimino- arylselenides and -tellurides

Article abstract of DOI:10.1016/j.inoche.2012.10.021

N-[N′,N′-Methylphenylamino(thiocarbonyl)]benzimidoyl chloride (1) reacts with in situ-prepared arylselenolates or aryltellurolates under formation of the first representatives of the corresponding iminoselenides or -tellurides. The products are air-stable

Full text of DOI:10.1016/j.inoche.2012.10.021

Inorganic Chemistry Communications 27 (2013) 40–42
Contents lists available at SciVerse ScienceDirect
Inorganic Chemistry Communications
journal homepage: www.elsevier.com/locate/inoche
Synthesis and characterization of N,N-methylphenylthiocarbamoylimino-
arylselenides and -tellurides
Barbara Tirloni a, Ernesto Schulz Lang a, Ulrich Abram b,
⁎
a
Departamento de Química, Laboratório de Materiais Inorgânicos, Universidade Federal de Santa María, 97105-900 Santa Maria, RS, Brazil
Freie Universität Berlin, Institute of Chemistry and Biochemistry, Fabeckstr. 34-36, D-14195 Berlin, Germany
b
a r t i c l e i n f o
a b s t r a c t
Article history:
N-[N′,N′-Methylphenylamino(thiocarbonyl)]benzimidoyl chloride (1) reacts with in situ-prepared arylselenolates
or aryltellurolates under formation of the first representatives of the corresponding iminoselenides or -tellurides.
The products are air-stable solids, which have been studied spectroscopically and by single-crystal X-ray
diffraction.
Received 31 July 2012
Accepted 12 October 2012
Available online 22 October 2012
© 2012 Elsevier B.V. All rights reserved.
Keywords:
Tellurium
Selenium
Thiourea derivatives
X-ray structure
N-[N′,N′-(Dialkylamino(thiocarbonyl)]benzimidoyl chlorides (1) are
versatile building blocks for the synthesis of bi-, tri- and tetradentate
ligand systems. Reactions with amines give the corresponding ben-
zamidines 2, which form stable complexes with a large number of
transition metals [1–11].
The use of arylchalcogene building blocks instead of the methyl
substituted ones increases the stability of the products. Thus, com-
pounds 3 and 4 can be obtained in good yields from one-pot reactions
of 1 (R=Me, Ph), the corresponding diselenides or ditellurides and
NaBH4 in ethanol [15] as deep yellow or orange-red solids. They are
stable as solids as well as in solution and can be obtained in crystal-
line form after recrystallization from toluene.
Only less is reported about reactions of 1 with chalcogenolates. An
early report describes the formation of the methylester 2a, -thioester
2b and -selenoester 2c of the diethylamino derivative [12]. The for-
mer two compounds have been used for the complexation of
thiophilic metal ions such as Ag+ and Hg2+ [13,14]. The selenium de-
rivative, however, is described as an instable solid, which slowly de-
composes, even when stored at low temperatures [12].
The 1H NMR spectra support the structure of products. It is inter-
esting to note that for the protons of the methylphenylamino residues
only one single methyl signal is observed. This is in contrast to the
spectra of corresponding thiocarbamoylbenzamidines, where hin-
dered rotation around the C\NR2 bonds doubles the NMR signal of
the respective residues [3–11]. Obviously, the compounds under
study possess located C\N double, while delocated π-systems are
found in the nitrogen derivatives. The 77Se and 125Te resonances at
440 ppm (3a), 596 ppm (4a) and 799 ppm (4b) appear in the ex-
pected ranges for aromatic organoselenium(II) and -tellurium(II)
compounds [16,17]. ESI mass spectra of the compounds show the mo-
lecular ion peaks of the compounds and give some evidence for
⁎
Corresponding author.
E-mail address: abram@chemie.fu-berlin.de (U. Abram).
1387-7003/$ – see front matter © 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.inoche.2012.10.021

B. Tirloni et al. / Inorganic Chemistry Communications 27 (2013) 40–42
41
Fig. 1. Ellipsoid representation of the molecular structure of 3a [20].
dimerization in the gas phase by the formation of cluster ions of the
composition of [M2 +K]+ or [M2+Na]+
.
Single crystal X-ray diffraction studies confirm the composition of
the title compounds [18]. Fig. 1 displays the molecular structure of
3a. Selected bond lengths are summarized in Table 1. The X-ray dif-
fraction results clearly confirm the conclusions from the spec-
troscopic studies and the formation of the target compound. The
arylselenolate unit has replaced the chlorine atom of 1 in a straight-
forward reaction. The resulting selenoester has Z configuration with
respect to the C10\N1 bond. This bond of 1.274(3) Å is clearly
shorter than the other carbon–nitrogen bonds in 3a and can be
assigned to a double bond. Nevertheless, some delocalization of π
electron density can be deduced for the C17\N1 and C17\N2
bonds. This delocalization, however, is small compared with the sit-
uation in the corresponding thiocarbamoylbenzamidines. There, an
almost ideal bond length equalization is found for the C\N bonds,
which also includes the bond to the dialkylamino groups [3–11].
The lower extend of such delocalization of electron density in the
title compounds also explains the fact that no hindered rotation
around the C17\N2 bonds is observed in the NMR spectra of the
compounds 3a, 4a and 4b.
The thiourea moiety of 3a has the expected planar structure and,
in accordance with the almost located N1=C10 double bond, the sul-
fur atom is not in plane with the selenium atom. The corresponding
Se1–C10–N1–C17 torsion angle is around 55°.
The molecular structure of the tellurium analogue 4a is very sim-
ilar to that of 3a. Therefore, no extra figure is given for this structure.
Selected bond lengths and angles are contained in Table 1 and the
atomic labeling scheme has been adopted from the selenium com-
pound. No significant differences of bond lengths and angles are ob-
served as a consequence of the replacement of selenium by the
heavier chalcogen.
Fig. 2. Ellipsoid representations of two molecules of 4b, which are arranged in a
pseudo-dimeric fashion by inversion symmetry [20].
Fig. 2 displays the molecular structure of the 4-methoxy-substituted
compound 4b. All general structural features of 3a and 3b are also found
in this iminotelluride. The main difference between the two tellurium
compounds is the Te1–C10–N1–C17 torsion angle, which is larger by
about 15° for 4b. This may have to do with the smaller steric stress
around the tellurium atom and causes another arrangement of the mol-
ecules in the solid state structure. Each two of the molecules of 4b are
arranged to pseudo-dimers via weak long-distance interactions be-
tween the tellurium and sulfur atoms. The corresponding distance is
3.698(1) Å, which is within the sum of the van der Waals radii of tellu-
rium and sulfur. Secondary interactions between tellurium and halogen
or sulfur atoms are not unusual and represent common features in the
structural chemistry of organotellurium (II) compounds [21–23]. In
the present case, such interactions have a significant influence on the
crystallization behavior of the tellurium compound.
In future studies, the title compounds will be tested as ligands in
transition metal complexes and precursors for the synthesis of
selenium- and tellurium-containing heterocycles. Another potential
field of application, which is widely unexplored up to now, is the use
of organoselenium and -tellurium compounds for pharmaceutical
purposes [24]. Some vinyltellurium derivatives have recently been
found to possess considerable anti-oxidant activity, which implies a
potential against excitotoxic agents [25,26]. The iminoselenides
and -tellurides 3 and 4 can be regarded as nitrogen analogues of
such active compounds.
Appendix A. Supplementary material
Table 1
Selected bond lengths (Å) and angles (°).
Supplementary data to this article can be found online at http://
dx.doi.org/10.1016/j.inoche.2012.10.021.
3a
4a
4b
S1–C17
C24–N2
C18–N2
C17–N2
C17–N1
N1–C10
C10–Se1/Te1
Se1/Te1–C1
C1–Se1/Te1–C10
Se1/Te1–C10–N1
N1–C17–S1
N1–C17–N2
S1–C17–N2
S1–C17–N1–C10
1.665 (1)
1.469 (4)
1.434 (4)
1.338 (4)
1.397 (3)
1.274 (3)
1.927 (3)
1.942 (3)
102.5 (1)
122.0 (2)
122.3 (2)
112.8 (2)
124.4 (2)
54.97 (1)
1.645 (6)
1.457 (7)
1.441 (7)
1.366 (7)
1.404 (6)
1.285 (6)
2.152 (5)
2.134 (5)
95.4 (2)
122.0 (3)
123.0 (4)
112.0 (5)
124.7 (4)
46.23 (1)
1.676 (4)
1.461 (8)
1.436 (5)
1.384 (5)
1.373 (5)
1.284 (4)
2.142 (3)
2.118 (3)
95.3 (1)
121.8 (3)
122.1 (3)
113.2 (4)
124.5 (3)
60.11 (1)
References
[1] L. Beyer, R. Widera, Tetrahedron Lett. 23 (1982) 1881.
[2] L. Beyer, J. Hartung, R. Widera, Tetrahedron 40 (1984) 405.
[3] H.H. Nguyen, J. Grewe, J. Schroer, B. Kuhn, U. Abram, Inorg. Chem. 47 (2008) 5136
(and references cited therein).
[4] J. Schroer, U. Abram, Polyhedron 28 (2009) 2277.
[5] H.H. Nguyen, P.I.da.S. Maia, V.M. Deflon, U. Abram, Inorg. Chem. 48 (2009) 25.
[6] H.H. Nguyen, V.M. Deflon, U. Abram, Eur. J. Inorg. Chem. (2009) 3179.
[7] H.H. Nguyen, J.J. Jegathesh, P.I.da.S. Maia, V.M. Deflon, R. Gust, S. Bergemann, U.
Abram, Inorg. Chem. 48 (2009) 9356.
[8] P.I.da.S. Maia, H.H. Nguyen, D. Ponader, A. Hagenbach, S. Bergemann, R. Gust, V.M.
Deflon, U. Abram, Inorg. Chem. 51 (2012) 1604.

42
B. Tirloni et al. / Inorganic Chemistry Communications 27 (2013) 40–42
[9] E. Oehlke, H.H. Nguyen, Nils Kahlcke, V. M. Deflon, U. Abram, Polyhedron 40
818 (s), 768 (m), 725 (s), 692 (m), 635 (m), 586 (m), 565 (w), 546 (m), 513 (m),
487 (w). ESI+MS (m/z): 1015 [M2+K]+, 999 [M2+Na]+, 529 [M+K]+, 513
(2012) 153.
[10] J. Schroer, U. Abram, Polyhedron 33 (2012) 218.
[11] J.D. Castillo Gomez, H.H. Nguyen, A. Hagenbach, U. Abram, Polyhedron 40 (2012)
123.
[M+Na]+ 491 [M+H]+ 1H NMR (CDCl3, ppm): 3.68 (s, 3H, CH3); 3.84 (s, 3H,
.
CH3); 6.50–7.51 (m, 14H, CHarom). 125Te NMR (CDCl3, ppm): 799.
[16] M. Lardon, J. Am. Chem. Soc. 92 (1970) 5063.
[12] R. Köhler, L. Beyer, A. Hantschmann, E. Hoyer, Z. Chem. 30 (1990) 102.
[13] S. Bender, E. Hoyer, G. Zahn, Z. Anorg. Allg. Chem. 625 (1999) 1489.
[14] F. Lessmann, L. Quas, L. Beyer, F. Dietze, J. Sieler, Z. Anorg. Allg. Chem. 626 (2000)
722.
[17] H.C.E. McFarlane, W. McFarlane, J. Chem. Soc., Dalton Trans. (1973) 2416.
[18] Crystal data for 3a: triclinic, space group P(−)1, a=9.549(1), b=11.735(1),
c=12.164(1) Å, α=103.29(1), ß=113.17(2), γ=107.56(1), V=1096.3(2) Å3,
Z=2. STOE-IPDS, Mo Kα radiation (λ=0.71073 Å), T=200 K, 12191 reflections
measured, 3916 independent, 255 parameters, μ=1.819 mm−1, absorption cor-
rection: integration, Tmin=0.6394, Tmax=0.8832. Structure solution and refine-
ment: SHELXS-97, SHELXL-97 [19], R1=0.0446, wR2=0.1048, GooF=0.935,
CCDC deposit number: CCDC-892938.Crystal data for 4a: triclinic, space group
P(−)1, a=8.771(3), b=11.405(4), c=11.773(4) Å, α=108.22(2), ß=100.70(2),
γ=90.69(2). V=1115.3(7) Å3, Z=2. STOE-IPDS, Mo Kα radiation (λ=0.71073 Å),
T=200 K, 12,846 reflections measured, 4465 independent, 254 parameters,
μ=1.439 mm−1, absorption correction: integration, Tmin=0.5574, Tmax=0.8695.
Structure solution and refinement: SHELXS-97, SHELXL-97 [19], R1=0.0622,
wR2=0.1519, GooF=1.071, CCDC deposit number: CCDC-892939.Crystal data for
4b: triclinic, space group P(−)1, a=8.935(1), b=10.961(1), c=11.760(1) Å,
α=68.86(1), ß=78.51(1), γ=85.06(1). V=1052.4(2) Å3, Z=2. STOE-IPDS, Mo
Kα radiation (λ=0.71073 Å), T=200 K, 11,338 reflections measured, 4223 inde-
[15] Synthesis of
3 and 4: the corresponding diaryldiselenide or -ditellurides
(0.2 mmol) were dissolved in 10 mL of dry ethanol and treated with NaBH4
(15 mg, 0.4 mmol) under an atmosphere of dry argon. The resulting colorless so-
lutions were added dropwise to stirred suspensions of 1 (115 mg, 0.4 mmol) in
5 mL of dry ethanol. The color immediately changed to deep yellow (3a and
4b) or orange red (4a) and yellow or orange red precipitates deposited within
2 h. The solids were filtered off and recrystallized from toluene.3a: yellow, crys-
talline solid. Yield: 125 mg (69 %). Elemental analysis: calc. for C24H24N2SSe: C,
63.85; H, 5.36; N, 6.20; S, 7.10%. Found: C, 62.85; H, 5.13; N, 5.7; S, 7.42%. IR
(KBr, νmax in cm−1): 3047 (w), 2966 (w), 2918 (w), 1589 (vs), 1574 (s), 1463
(s), 1443 (s), 1359 (vs), 1317 (m), 1296 (s), 1284 (s), 1231 (m), 1178 (m),
1155 (s), 1107 (s), 1076 (m), 1022 (m), 924 (m), 897 (s), 860 (m), 844 (m),
772 (vs), 727 (vs), 694 (vs), 667 (m), 640 (s), 598 (m), 550 (s), 529 (w), 467
(w). ESI+MS (m/z): 943 [M2+K]+
,
927 [M2+Na]+
,
491 [M+K]+
,
475
pendent, 246 parameters, μ=1.524 mm−1
min=0.5341, Tmax=0.8263. Structure solution and refinement: SHELXS-97,
, absorption correction: integration,
[M+Na]+, 453 [M+H]+. High resolution MS of [M+Na]+, which is the base
peak of the spectrum: calc.: 475.0723, Found: 475.0733. 1H NMR (CDCl3, ppm):
2.13 (s, 3H, CH3); 2.25 (s, 6H, CH3); 3.83 (s, 3H, CH3); 6.69–7.45 (m, 12H, CHarom).
77Se NMR (CDCl3, ppm): 440.4a: orange-red, crystalline solid. Yield: 136 mg (68 %).
Elemental analysis: calc. for C24H24N2STe: C, 57.64; H, 4.84; N, 5.60; S, 6.41 %. Found:
C, 57.29; H, 4.69; N, 5.30; S, 6.51%. IR (KBr, νmax in cm−1): 3015 (w), 2965 (w), 2914
(w), 1596 (s), 1558 (vs), 1491 (s), 1458 (s), 1444 (s), 1371(vs), 1315 (m), 1294 (s),
1285 (s), 1229 (m), 1179 (m), 1152 (s), 1111 (s), 1074 (m), 1022 (m), 1001 (w),
916 (w), 895 (s), 848 (m), 837 (m), 762 (s), 727 (vs), 698 (s), 690 (vs), 663 (m),
637 (s), 584 (m), 569 (m), 550 (m), 457 (w). ESI+MS (m/z): 541 [M+K]+, 525
T
SHELXL-97 [19], R1=0.0472, wR2=0.1223, GooF=1.053, CCDC deposit number:
CCDC-892940.
[19] G.M. Sheldrick, SHELXS-97 and SHELXS-97 — A Programme Package for the Solution
and Refinement of Crystal Structures, University of Göttingen, Germany, 1997.
[20] a) K. Brandenburg, H. Putz, Diamond — A Crystal and Molecular Structure Visu-
alisation Software Crystal Impact, Bonn, Germany.
[21] S. Husbye, Phosphorus, Sulfur, Silicon 136 (1998) 377.
[22] M.D. Rudd, S.V. Lindeman, S. Husbye, Phosphorus, Sulfur, Silicon 123 (1997) 313.
[23] H.E. Bailey, J.E. Drake, A.B. Sarkar, M.L.Y. Wong, Can. J. Chem. 68 (1989) 1734.
[24] E.R.T. Tiekink, Dalton Trans. 41 (2012) 6390.
[25] V.C. Borges, L. Savegnago, S. Pinton, C.R. Jesse, D. Alves, C.W. Nogueira, J. Appl.
Toxicol. 28 (2008) 839.
[26] D.S. Avila, P. Gubert, A. Palma, D. Colle, D. Alves, C.W. Nogueira, J.B.T. Rocha, D.A.A.
Soares, Brain Res. Bull. 76 (2008) 114.
[M+Na]+, 503 [M+H]+ 1H NMR (CDCl3, ppm): 2.12 (s, 3H, CH3); 2.39 (s, 6H,
.
CH3); 3.86 (s, 3H, CH3); 6.69–7.46 (m, 12H, CHarom). 125Te NMR (CDCl3, ppm):
596.4b: deep yellow, crystalline solid. Yield: 129 mg (66 %). Elemental analysis:
calc. for C22H20N2OSTe: C, 54.14; H, 4.13; N, 5.74; S, 6.57%. Found: C, 54.30; H,
4.12; N, 5.67; S, 6.62%. IR (KBr, νmax in cm−1): 3026 (w), 2991 (w), 2931 (w),
2829 (w), 1589 (vs), 1487 (vs), 1442 (vs), 1375 (vs), 1285 (vs), 1244(vs), 1175
(vs), 1152 (vs), 1107 (s), 1065 (m), 1033 (s), 1001 (m), 972 (w), 920 (w), 887 (s),