Organometallic tin compounds derived from 2-benzimidazole propionic acid

Article abstract of DOI:10.1002/zaac.201300108

Reactions of 2-benzimidazole propionic acid (1) with [Sn(nBu) ₃]₂O and SnPh₃OH gave mononuclear organometallic tin esters 2 and 3, respectively, where 1 is coordinated to the tin atom through the carboxylate group. Further reactions of 2 with DMSO and 3 with methanol, ethanol, pyridine, DMSO, THF and water afforded the corresponding tin compounds coordinated by the base 4-10, respectively. X-ray diffraction analyses of 5, 6 and 10 were obtained. The solid-state structures showed that the ligand 1 is bound through both oxygen atoms of the carboxylic group with the Lewis base anti to it. Reaction of 1 with di-n-butyltin oxide produced a tetranuclear distannoxane (11) by the association of four Sn(nBu)₂ groups, two oxygen atoms and four ligands. Four of the oxygen atoms are tricoordinate. The tin atoms are hexacoordinate with distorted octahedral geometries. The macromolecule has in total seven fused rings. Five of them are four membered rings arranged in a ladder-type arrangement and the other two are six membered rings. The aliphatic chains and the benzimidazole groups are perpendicularly oriented to the polycyclic arrangement giving a sandwich with polar bonds in the middle and covered by the aliphatic and aromatic groups. In all compounds the ligands showed a chiral helicoidal preferred conformation. Copyright

Full text of DOI:10.1002/zaac.201300108

ARTICLE
DOI: 10.1002/zaac.201300108
Organometallic Tin Compounds Derived from 2-Benzimidazole Propionic
Acid
Carlos Camacho-Camacho,[a,b] Adriana Esparza-Ruiz,[a,c] Adrián Peña-Hueso,[a]
Edgar Mijangos,[a] Iris Ramos-García,[a] Rosalinda Contreras,[a] and
Angelina Flores-Parra*[a]
Dedicated to Professor Heinrich Nöth on the Occasion of His 85th Birthday
Keywords: Hypervalent tin compounds; 2-Benzimidazole propionic acid; Tin; X-ray diffraction
Abstract. Reactions of 2-benzimidazole propionic acid (1) with distannoxane (11) by the association of four Sn(nBu)2 groups, two
[Sn(nBu)3]2O and SnPh3OH gave mononuclear organometallic tin es-
oxygen atoms and four ligands. Four of the oxygen atoms are tricoord-
ters 2 and 3, respectively, where 1 is coordinated to the tin atom inate. The tin atoms are hexacoordinate with distorted octahedral geo-
through the carboxylate group. Further reactions of 2 with DMSO and metries. The macromolecule has in total seven fused rings. Five of
3 with methanol, ethanol, pyridine, DMSO, THF and water afforded them are four membered rings arranged in a ladder-type arrangement
the corresponding tin compounds coordinated by the base 4–10, and the other two are six membered rings. The aliphatic chains and the
respectively. X-ray diffraction analyses of 5, 6 and 10 were obtained.
The solid-state structures showed that the ligand 1 is bound through
both oxygen atoms of the carboxylic group with the Lewis base anti
to it. Reaction of 1 with di-n-butyltin oxide produced a tetranuclear
benzimidazole groups are perpendicularly oriented to the polycyclic
arrangement giving a sandwich with polar bonds in the middle and
covered by the aliphatic and aromatic groups. In all compounds the
ligands showed a chiral helicoidal preferred conformation.
tion of 1 with several transition metals is evident as described
Introduction
previously for CuII,[14] CoII,[15,16] and Ag.[17]
We are interested in the preparation of organometallic tin
compounds derived from biologically active molecules.[1–5]
One of the aims of our research is the structural analysis of the
organometallic tin compounds, particularly their coordination
modes, which has influence in the biological effects. The poly-
functional nature of 1 could favor the formation of seven mem-
bered ring, chelate which is seldom observed.[6] The impor-
tance of organotin(IV) carboxylates[7,8] is due to their signifi-
cant antitumor[9] and cytotoxic activity[10,11] as well as to their
possible use as mosquitos larvicides.[12]
Figure 1. X-ray diffraction structure of ligand 1.[13]
The X-ray diffraction molecular structure of 1 has been al-
ready published.[13] It is a zwitterion in an unexpected gauche
and chiral conformation, with the carboxylate pointing towards
the back, like a scorpion tail, Figure 1. The versatile coordina-
Results and Discussion
Mononuclear Compounds 4–10
* Prof. Dr. A. Flores-Parra
E-Mail: aflores@cinvestav.mx
[a] Chemistry Department, Cinvestav
México, A.P. 14–740
The reaction of 2-benzimidazole propionic acid (1) with
(nBu3Sn)2O or Ph3SnOH affords tin(V) compound 2 and 3
respectively, Scheme 1. In compound 2, the ligand is linked to
the tin by the propionate anion, as was deduced from the 119Sn
NMR signal (δ = +117 ppm, CDCl2), similar to that of
Me3SnOCOMe (δ = +96 ppm in CH2Cl2)[18] and by the cou-
pling constants (Hz) of the n-butyl groups [1J(13C,119/117Sn) =
México D.F., 07000, México
[b] Departamento de Sistemas Biológicos
Universidad Autónoma Metropolitana Xochimilco
Calzada del Hueso 1100, Col. Villa Quietud
México, 04960 D.F, México
[c] Cuerpo Académico de Química Fundamental y Aplicada
Universidad Autónoma de Yucatán
Periférico Norte, Km 33.5, Tablaje Catastral de 13615
Chuburna de Hidalgo
2
3
361/354; J(13C,119Sn) = 21; J(13C,119Sn) = 65 Hz], as well
97203, Mérida Yucatán, México
as the IR band at 743 cm–1 (Sn–O).
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Z. Anorg. Allg. Chem. 2013, 639, (7), 1122–1128

Organometallic Tin Compounds Derived from 2-Benzimidazole Propionic Acid
[10Py, N···HO bond length = 1.85(6) Å, O–H–N angle =
161(5)°; 10DMSO, OH···O bond length = 2.00(9) Å; O–H–O
angle = 173(13)°]. Capped stick representations for the crystal-
line structures found in the crystals are in Figure 3. Selected
bond lengths and angles are in Table 1.
Scheme 1. Syntheses of compounds 2–10.
Figure 3. Solid state structures of 10py left, and 10DMSO right. Hydro-
gen bonds with Lewis bases are shown.
The 119Sn NMR spectrum of 3 in CDCl3 (δ = –101.6 ppm)
indicates also that the ligand is only bound to the tin atom by
the propionic anion; as was deduced by the comparison to data
of Ph3SnOCOMe (δ = –113 ppm, CDCl3[18]). In the IR the
Sn–O band at 730 cm–1 and a sharp peak at 1078 cm–1 for the
Sn–Ph3 group confirmed the tin ester formation.[19]
Table 1. Selected bond lengths /Å and angles /° for 5, 6 and 10.
Addition of DMSO to a solution of compound 2 in CD2Cl2
gives the coordinated compound 4 as was observed by 119Sn,
1H and 13C NMR spectra [δ = 119Sn: + 21.4 ppm]. Whereas
addition of the Lewis bases (methanol, ethanol, pyridine,
DMSO and THF) to a solution of 3 in CDCl3 afforded the
corresponding hexacoordinate compounds (5–9) as was estab-
lished by the 119Sn, 1H and 13C NMR spectra [δ = 119Sn: –223
(5); –216 (6); –242 (7); –261 (8) and –150 ppm (9)]. After few
days, crystals were formed in the NMR tubes of compounds
5–9 which were submitted to the X-ray diffraction analyses.
The crystals of the solution of compounds 5 and 6 showed
that a methanol or an ethanol molecule was coordinated to the
tin atom as was deduced from the NMR spectra. The ORTEP
representation of 5 and 6 is shown in Figure 2.
4
6
10Py
10DMSO
Sn–O1
Sn–O3
C4–O2
C4–O1
Sn–C1
Sn–C2
Sn–C3
2.127(2)
2.481(3)
1.227(4)
1.295(4)
2.122(4)
2.130(3)
2.139(3)
2.140(2)
2.465(2)
1.220(4)
1.300(4)
2.138(3)
2.136(3)
2.133(3)
2.161(3)
2.396(3)
1.221(5)
1.290(4)
2.128(3)
2.137(3)
2.136(3)
2.157(4)
2.402(4)
1.227(7)
1.289(6)
2.133(5)
2.120(5)
2.135(5)
O1–Sn–O3
C1–Sn–C2
C2–Sn–C3
C3–Sn–C1
O2–C4–O1
174.9(1)
123.7(1)
117.6(1)
116.7(1)
124.4(3)
177.4(1)
130.9(1)
114.4(1)
113.3(1)
122.9(3)
170.2(1)
119.3(1)
122.1(1)
116.9(1)
123.6(4)
175.2(2)
130.2(2)
113.3(2)
114.8(2)
123.2(5)
In the three molecules 5, 6 and 10 the tin has a distorted
octahedral geometry. It is coordinated by a bidentate carboxyl-
ate. The sixth coordination comes from an oxygen atom of
methanol (5), ethanol (6) or water (10) and is anti to the carb-
oxylate, O1–Sn–O3 angles are in the range of 170.19(9)–
177.39 (9). The Sn–O bond lengths vary from 2.127(2) to
Figure 2. ORTEP representations of compounds 5 and 6. Displace-
ment ellipsoids are drawn at the 50% probability level.
The X-ray diffraction analyses of the crystals (10py and 2.162(3) Å for Sn–O1 and from 2.396(3) to 2.482(3) Å for
10DMSO) formed in the tube of compounds 7 and 8 showed Sn–O3, all of them are longer than the sum of reported cova-
that instead of the pyridine or the DMSO, a water molecule lent radii [Σrcov (Sn–O) = 2.05 Å].[20] Oxygen atom O2 is
was coordinated to the tin atom (10) displacing the base. The weakly coordinated to the tin as is denoted by the longer bonds
pyridine and the DMSO crystallized with the tin compound [from 3.030(3) to 3.220(2) Å], but is still shorter than the sum
(10) associated by hydrogen bonds to the coordinated water of their van der Waals radii [ΣrvdW (Sn–O) = 3.80 Å].[21] The
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A. Flores-Parra et al.
ARTICLE
O2ǞSn coordination bond is also deduced from the opening
of the C–Sn–C angles of the two phenyl groups in front of O2.
The C–Sn–C angles vary from 122.1 to 131.0(1)°.
Compounds 5, 6 and 10 are chiral (C1) due to the preferred
helicoidal conformation of the ligand. Both enantiomers are
found in the crystals, Figure 4. The ligand conformation in the
solid state is also stabilized by C–H···π interactions, Figure 5.
Figure 4. Enantiomeric preferred conformations found in the crystals
of compounds 5, 6 and 10.
Figure 7. Tetramer formed by O3H···N [2.15(6) Å, O3–H–N angle =
166(6)°] and NH···O2 [2.09(6) Å, N–H–O2 angle = 169(6)°] hydrogen
bonds in 10Py.
hydrogen bonds O3H···N between the coordinated water mole-
cule and the imidazole, Figure 7.
Tetranuclear Compound 11
The reaction of di-n-butyltin oxide with ligand 1 in a mix-
ture of ethanol:toluene 1:4 afforded the distannoxane 11.
Evaporation of the solvents gave crystals. This product was
insoluble in common solvents; therefore it was only analyzed
by X-ray diffraction. The solid state analysis of compound 11
shows a tetranuclear Sn complex from the association of four
benzimidazole ligands, Figure 8. The four tin atoms are hexa-
Figure 5. C–H···π interactions stabilize the ligand conformation in
compound 5.
Enantiomers of compounds 5, 6 and 10 form strong dimers
by two cooperative hydrogen bonds between the proton NH
and the oxygen of the carboxylate groups. Dimers are arranged
in fourteen membered rings. The dimer of compound 10DMSO
is depicted in Figure 6. In 10Py a tetramer is formed through
Figure 8. The molecular structure of 11, (R = nBu) showing displace-
Figure 6. Fourteen membered ring dimer formed by cooperative ment ellipsoids at the 50% probability level. All carbon atoms of
NH···O hydrogen bonds in crystal 10DMSO n-butyl groups were omitted for clarity.
.
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Z. Anorg. Allg. Chem. 2013, 1122–1128

Organometallic Tin Compounds Derived from 2-Benzimidazole Propionic Acid
coordinate in distorted octahedral geometry. Two benzimid-
azole are linked to two tin atoms by one carboxylate oxygen
atom (bond lengths 2.29 and 2.23 Å), where the other two li-
gands have both carboxylate oxygen atoms bound to two tin
atoms through a covalent bond (Sn–O = 2.18 Å) and a coordi-
nation bond (SnǟO = 2.97 Å). The oxygen atoms bridging the
tin atoms are tricoordinate. The macromolecule has in total
seven fused rings in a planar framework. Five of them are four
membered rings where five of them arranged in a ladder and
the other two are six membered rings. Selected bond lengths
and angles are in Table 2.
Figure 9. a) Fused seven rings forming the core of compound 11.
Sn···Sn and O···O distances are shown. b) Spacefill representation of
the tin core of compound 11.
Table 2. Selected bond lengths /Å and angles /° for 11.
Sn1–O1
Sn1–O2
Sn1–O3
Sn1–O5
Sn1–C3
Sn1–C4
C1–O5
C1–O2
2.028(2)
2.181(2)
2.229(2)
2.792(2)
2.121(4)
2.127(4)
1.223(4)
1.297(4)
Sn2–O1
Sn2–O1’
Sn2–O2
Sn2–O4
Sn2–C5
Sn2–C6
C7–O3
2.052(2)
2.149(2)
2.655(2)
2.290(2)
2.124(3)
2.106(4)
1.256(4)
1.261(4)
Figure 10. The enantiomeric conformations of the two pairs of coordi-
nated ligands (+A and -A and +B and -B) in compound 11 are shown.
C7–O4
rangement, Figure 11. The structure is like a sandwich with
polar bonds in the middle and covered by the aliphatic and
aromatic groups.
O3–Sn1–O2
O3–Sn1–C4
O2–Sn1–C4
O3–Sn1–C3
O2–Sn1–C3
C4–Sn1–C3
O3–Sn1–O1
O2–Sn1–O1
C4–Sn1–O1
C3–Sn1–O1
Sn1–O1–Sn2
Sn1–O2–C1
Sn1–O3–C7
169.1(1)
90.2(1)
94.8(1)
85.2(2)
97.2(2)
139.3(2)
91.08(8)
78.15(8)
109.4(1)
111.0(1)
136.6(1)
113.1(2)
133.7(3)
O4–Sn2–C5
O4–Sn2–C6
C5–Sn2–C6
O4–Sn2–O1
C5–Sn2–O1
C6–Sn2–O1
O1–Sn2–O1’
Sn2–O1–Sn2
Sn2–O2–Sn1
Sn2–O4–C7
O3–C7–O4
82.3(1)
85.7(2)
144.2(1)
88.33(8)
107.1(1)
106.1(1)
75.91(9)
104.1(1)
95.55(9)
135.1(3)
124.4(3)
The fused rings arrangement is shown in Figure 9a. It is
noteworthy that the tin atoms in the central square have Sn···Sn
distances of 3.3(3) Å shorter than their sum of van der Waals
radii (4.5 Å), which is also the case for the oxygen atoms
(O···O distance is 2.58 Å, ΣrvdW 3.1 Å[21]). The van der Waals
radii representation of the fused rings core is given in Fig-
ure 9b.
The four ligands in the tin core of 11 are arranged in two
pairs of enantiomeric conformations: ligands +A and –A; +B
and –B. Each ligand pair is differently coordinated to the tin
atom, Figure 10.
Figure 11. View of compound 11 showing the perpendicular arrange-
ment of n-butyl and imidazole groups with respect to the tin oxygen
core plane.
It is interesting that the aliphatic chains and the benzimid-
Ribbon arrangement of distannoxane 11 linked by four co-
azole groups are perpendicularly oriented to the polycyclic ar- operative CH···π interactions [2.857 and 2.882 Å, with angles
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A. Flores-Parra et al.
ARTICLE
Figure 12. Ribbon arrangement of compound 11 formed by CH···π contacts.
Kappa CCD instrument with CCD area detector using graphite-mono-
chromated Mo-Kα radiation at 293 K. Intensities were measured using
φ + ω scans. A summary for data collection and refinements is given
in Table 3. All structures were solved by direct methods, as SHELX-
97[23] and the refinement (based on F2 of all data) was performed by
full-matrix least-squares techniques with Crystals 12.84.[24] All non-
hydrogen atoms were refined anisotropically. For 5, 6 and 10DMSO all
of 132.2 and 141.7°, respectively] is observed in the crystal
and represented in Figure 12. Other distanoxanes with similar
structures are known.[7–8,22]
Summary
The 2-benzimidazole propionic acid 1 forms mononuclear hydrogen atoms were refined and allowed to ride to their respective.
For 5 and 6, only the position of the O3–H was refined. For 6, the
ethanol molecule was disordered and their hydrogen atoms were re-
stricted to fit ideal positions. For 10DMSO, the N–H, and the two O–H
hydrogen atoms were refined and all other found, refined and allowed
to ride to their respective atoms; the hydrogen atoms of DMSO mole-
cule were calculated and they were restricted to fit ideal positions. For
10Py all hydrogen atoms were refined. For 11, the N–H hydrogen atoms
were refined. The phenyl hydrogen atoms were found and allowed to
ride; hydrogen atoms of n-butyl group were placed on geometrically
calculated positions.
tin esters (2 and 3) with tri-butyltin oxide and triphenyltin hy-
droxide, respectively. Compound 2 was coordinated to DMSO
(4) indicating that the carboxylic group induces a strong acidic
character to the tin atom, even in the presence of the electronic
donor n-butyl groups. Compound 3 reacted with different
Lewis bases (B) [B = methanol (5), ethanol (6), pyridine (7),
dimethylsulfoxide (8), tetrahydrofurane (9) and water (10)] to
form hexacoordinate tin derivatives, where the benzimidazole
is linked only through the carboxylic group. The chiral pre-
ferred conformation of the ligand gives C1 tin molecules,
where both enantiomers are found in the crystalline structures.
In none compounds the benzimidazole nitrogen atom par-
ticipate in the tin coordination sphere, however it favors strong
hydrogen bonds that allow the formation of macromolecular
arrangements.
CCDC data for 5 (918914), 6 (918911), 10Py (918912), 10DMSO
(918913) and 11 (918910) can be obtained free of charge
from The Cambridge Crystallographic Data Centre via http://
www.ccdc.cam.ac.uk/data_request/cif.
Distannoxane 11 is the result of the association of four
Sn(nBu)2 groups, four ligands and two central oxygen atoms.
Four of the oxygen atoms are tricoordinate. The four tin atoms
are hexacoordinate with distorted octahedral geometries. The
macromolecule has in total seven fused rings in an almost
planar rearrangement. The aliphatic chains and the benzimid-
azole groups are perpendicularly oriented to the polycyclic ar-
rangement giving a sandwich molecule with polar bonds in the
middle and covered by the aliphatic and aromatic groups.
Tributylstannyl 3-(1H-benzimidazol-2-yl)propanoate (2)
A mixture of 2-benzimidazole propionic acid (0.38 g, 2.0 mmol) and
(nBu3Sn)2O (0.60 g, 1.0 mmol) in absolute ethanol (3 mL) and dry
toluene (12 mL) were placed in a flask equipped with a Dean–Stark
trap filled with dry toluene. The mixture was stirred and refluxed for
3 hr. Then, the toluene was evaporated and a colorless solid was ob-
tained. It was recrystallized from ethyl acetate/hexane (3:1). Mp:
65 °C. Yield: 0.74 g (83%). NMR CDCl3, 25 °C): δ = (ppm), 1H: 7.53
(H6), 7.19 (H7), 3.21 (H2), 2,85 (H3), {nBu group: 1.60 (m, Hβ), 1.33
(m, Hγ), 1.26 (m, Hα), 0.9 (t, Hδ)}. 13C: 178.5 (C1), 154.8 (C4), 138.7
(C5), 121.7 (C7), 114.5 (C6), 32.9 (C2), 25.2 (C3), {nBu group: 27.8
[2J(13C,119Sn) 21 Hz, Cβ], 27.0 [3J(13C,119Sn) 65 Hz, Cγ], 16.5
[1J(13C,119Sn) 361 Hz, Cα], 13.4(Cδ)]. IR (KBr), ν (cm–1): 3202, 2957,
2922, 1613, 1415, 1393, 1290, 740. MS (+)TOF (amu): [M + H]+
calcd. C22H37N2O2Sn: 481.1871; exp. 481.1870. C22H36N2O2Sn⋅H2O:
calcd. C 53.14, H 7.70, N 5.63; found: C 52.83, H 7.77, N 5.29 %.
Experimental Section
Melting points were determined on Melt Temp II equipment in an open
capillar tube and are not corrected. IR spectra were taken in KBr discs
using a FT GX Perkin–Elmer spectrometer. EI mass spectra were per-
formed in a Hewlett–Packard HP 5989A spectrometer. High resolution
mass spectra were obtained by LC/MSD TOF on an Agilent Technol-
Addition of [D6]DMSO to a solution of compound 2 in CD2Cl2 gives
1
ogies instrument with APCI as ionization source. Elemental analyses compound 4: NMR (CD2Cl2/[D6]DMSO, 25 °C): δ = (ppm), H: 7.44
were carried out in a Flash 1112 Thermo Finnigan analyzer. NMR
(H6), 7.09 (H7), 3.06 (H2), 2,70 (H3), {nBu group: 1.56 (m, Hβ), 1.27
spectra were recorded with JEOL Eclipse (400 MHz) and Bruker (m, Hγ), 1.12 [m, 2J(1H,119Sn) 58 Hz, Hα], 0.85 (t, Hδ)}. 13C: 176.5
(300 MHz) instruments. 1H and 13C (Ξ 25.145020) chemical shifts are (C1), 155.1 (C4), 139.2 (C5), 121.3 (C7), 114.8 (C6), 33.7 (C2), 28.1
referenced to Si(CH3)4, 119Sn (Ξ 37.290665) to Sn(CH3)4. All X-ray (C3), {nBu group: 28.1 [3J(13C,119Sn) 25.4 Hz, Cγ], 27.1 [2J(13C,119Sn)
diffraction data were measured using standard procedures on a Nonius
73 Hz, Cβ], 18.1 [1J(13C,119Sn) 436 Hz, Cα], 13.8 (Cδ)}.
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Organometallic Tin Compounds Derived from 2-Benzimidazole Propionic Acid
Table 3. Crystal and data collection parameters of 5, 6, 10Py, 10DMSO and 11.
Compound
5
6
10Py
10DMSO
11
Empirical formula
C29H28N2O3Sn
2(C30H30N2O3Sn)·C2H6O C28H26N2O3Sn·
C5H5N
C28H26N2O3Sn·
C2H6OS
635.35
Monoclinic
P21/c
16.5996(2)
10.5157(2)
18.7855(3)
90
114.5800(6)
90
2981.98(8)
4
1.415
0.96
293
C72H108N8O10Sn4·
2(C2H6O)·2(H2O)
1848.63
Formula weight
Crystal system
Space group
a /Å
b /Å
c /Å
571.24
Monoclinic
C21/n
13.5014(2)
12.2363(2)
16.9376(3)
90
109.9805(7)
90
2629.79(8)
4
1.443
1.00
293
1216.61
Monoclinic
C2/c
636.32
Triclinic
Triclinic
¯
¯
P1
P1
30.7996(5)
10.6354(2)
17.5771(3)
90
93.3862(8)
90
9.8277(2)
10.5763(2)
15.9886(3)
74.6573(11)
78.6858(12)
68.1563(10)
1478.68(5)
2
12.4318(2)
13.7117(2)
15.5822(2)
101.6706(5)
104.3625(6)
115.8014(5)
2165.09(6)
1
α /°
β /°
γ /°
Volume /Å3
Z
5747.61(17)
4
ρ /Mg m–3
µ /mm–1
T /K
1.406
1.429
1.418
1.20
173
0.92
0.90
293
293
Crystal color
Crystal size /mm
θmax /°
Colorless prism
0.32 ϫ 0.25 ϫ 0.25 0.28 ϫ 0.25 ϫ 0.1
27.5
Colorless prism
Colorless prism
0.38 ϫ 0.25 ϫ 0.25
30.5
Colorless prism
0.32 ϫ 0.2 ϫ 0.15
30.6
Colorless prism
0.15 ϫ 0.1 ϫ 0.1
28.7
30.5
Limiting indices
–17 Յ h Յ 17;
–15 Յ k Յ 15;
–21 Յ l Յ 21
6005
–41 Յ h Յ 32;
–14 Յ k Յ 14;
–24 Յ l Յ 24
35433
–14 Յ h Յ 14;
–15 Յ k Յ 15;
–22 Յ l Յ 21
16034
–22 Յ h Յ 22;
–14 Յ k Յ 14;
–17 Յ l Յ 17
31775
–16 Յ h Յ 16;
–18 Յ k Յ 18;
–21 Յ l Յ 20
31728
Reflections collected
Independent reflections 3513
8219
8000
6871
10678
R (int)
0.089
0.067
0.055
0.057
0.039
Parameters
Observed reflections
S
322
354
454
361
556
3513 I Ͼ 3.0σ(I)
1.06
3972 I Ͼ 3.0σ(I)
1.02
5494 I Ͼ 3.0σ(I)
1.04
3527 I Ͼ 3.0σ(I)
1.00
7704 I Ͼ 3.0σ(I)
1.10
Final R1
0.029
0.031
0.042
0.036
0.032
Final wR2
0.037
0.037
0.049
0.039
0.037
Addition of C5H5N to a solution of compound 3 in CDCl3 gave com-
pound 7. NMR (C5H5N/CDCl3, 25 °C): δ = (ppm), 1H: 8.13
[3J(1H,119Sn) 65 Hz, Ho], 7.56 (Hp), 7.50 (Hm), 7.47 (H6), 3.43 (H2),
Triphenylstannyl 3-(1H-benzimidazol-2-yl)propanoate (3)
The same procedure as described for 2 was followed for 3. 2-benzimid-
azole propionic acid (0.38 g, 2.0 mmol), Ph3SnOH (0.73 g, 2.0 mmol),
absolute ethanol (3 mL), and dry toluene (12 mL). The product is a
colorless solid. It was recrystallized from CH2Cl2/hexane (3:1). Mp
170 °C. Yield: 0.80 g (74%). NMR (CDCl3, 25 °C): δ = (ppm), 1H:
7.70 [2J(1H,119Sn) 60 Hz, Ho], 7.47 (Hm, Hp), 7.42 (H6) 7.18 (H7),
3.20 (H2), 2.91 (H3). 13C: 180.0 (C1), 154.0 (C4), 137.5 (Ci), 136.5
(Cm), 130.5 (Co, Cp), 116.0 (C6), 32.7 (C2), 25.0 (C3). IR (KBr, ν˜
= cm–1): 3448, 3060, 3040, 1591, 1425, 1385, 729, 696. MS (+)TOF
(amu): [M + H]+ calcd. C28H25N2O2Sn: 541.0932; exp. 541.0937.
C28H24N2O2Sn: calcd. C 62.37, H 4.49, N 5.20; found: C 62.05, H
4.53, N 5.31 %.
3.10(H3). 13C: 177.9 (C1), 156.6 (C4), 144.0 [1J(13C,119 117
Sn) = 805/
/
768 Hz, Ci], 141.1 (C5), 138.1 [3J(13C,119Sn) 45 Hz, Cm], 130.5 (Cp),
129.9 (Co), 122.7 (C7), 116.2 (C6), 35.1 (C2), 26.9 (C3). After few
days crystals (10Py) were obtained in the NMR tube, which were sub-
mitted to X-ray diffraction analyses.
Addition of C2H6SO to a solution of compound 3 in CDCl3 gave com-
pound 8. NMR (C2H6SO/CDCl3, 25 °C): δ = (ppm), 1H: 7.81 (Ho),
7.45 (H6), 7.37 (Hm), 7.12 (C7), 2.94 (H2), 2.64 (H3). 13C: 175.6
(C1), 155.1 (C4), 144.1 [1J(13C,119 117
Sn)] = 829/791 Hz, Ci], 139.0
/
(C5), 136.6 [3J(13C,119Sn) 47 Hz, Cm), 139.0 (C5), 129.2 (Cp), 128.6
[2J(13C,119Sn) 70 Hz, Co], 121.5 (C7), 114.4 (C6), 34.0 (C2), 25.6
(C3). After few days crystals (10DMSO) were obtained in the NMR
tube, which were submitted to X-ray diffraction analyses.
Compounds 5–9
Addition of CD3OD to a solution of compound 3 in CDCl3 gave com-
pound 5. NMR (CD3OD/CDCl3, 25 °C): δ = (ppm), 1H: 7.53
[3J(1H,119Sn) 6.6 Hz, Ho], 7.11 (H6), 7.10 (Hp), 7.08 (Hm), 6.8 (H7),
2.74 (H2), 2.48 (H3). 13C: 179.0 (C1), 156.1 (C4), 142.3 (Ci), 140.2
(C5), 138.1 [3J(13C,119Sn) 47 Hz, Cm] 130.9 [4J(13C,119Sn) 14 Hz, Cp],
130.0 [2J(13C,119Sn) 66 Hz, Co], 123.0 (C7), 116.0 (C6), 34.2 (C2),
26.4 (C3).
Addition of C4H8O to a solution of compound 3 in CDCl3 gave com-
pound 9. NMR (C4H8O/CDCl3, 25 °C): δ = (ppm), 1H: 7.78
[3J(1H,119Sn) 66 Hz, Ho], 7.38 (Hm, Hp, H6), 7.03 (H7), 3.04 (H2),
2.82 (H3). 13C: 178.1 (C1), 154.1 (C4), 140.0 (Ci), 139.0 (C5), 136.5
(Cm), 129.5 (Cp), 128.5 (Co), 121.0 (C7), 114.4 (C6), 32.2 (C2), 25.5
(C3).
Addition of C2H5OD to a solution of compound 3 in CDCl3 gave
compound 6. NMR (C2H5OD/CDCl3, 25 °C): δ = (ppm), 1H: 7.52
[3J(1H,119Sn) 7 Hz, Ho], 7.10 (H6), 7.10 (Hp), 7.07 (Hm), 6.9 (H7),
2.70 (H2), 2.47 (H3). 13C: 179.1 (C1), 156.2 (C4), 142.0 (Ci), 140.2
Tetra-n-Butyl Bis(3-(1H-benzimidazol-2-yl)propanoate)
Distannoxane (11)
(C5), 138.3 [3J(13C,119Sn) 48 Hz, Cm] 131.8 [4J(13C,119Sn) 15 Hz, Cp], The same procedure as described for 2 was followed for 11. The 2-
131.0 [2J(13C,119Sn) 66 Hz, Co], 123.2 (C7), 115.9 (C6), 34.1 (C2), benzimidazole propionic acid (0.57 g, 3.0 mmol) and Bu2SnO (0.75 g,
27.0 (C3).
3.0 mmol), were dissolved in a mixture of absolute ethanol (3 mL) and
Z. Anorg. Allg. Chem. 2013, 1122–1128
© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.zaac.wiley-vch.de 1127

A. Flores-Parra et al.
ARTICLE
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2958, 2926, 1573, 1417, 1273, 741. - C72H108N8O10Sn4⋅(CH3CH2OH)
4·(CH2Cl2)2: Calcd. C 47.45, H 6.61, N 5.40; found: C 47.15, H 6.85,
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Acknowledgments
We thank Professor Angeles Paz-Sandoval for helpful discussions.
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Received: February 21, 2013
Published Online: May 15, 2013
1128
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© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2013, 1122–1128