Hypervalent triphenyl and diphenyl tin coordination compounds derived from 2-(1H-benzimidazol-2-yl)phenol

Article abstract of DOI:10.1016/j.jorganchem.2008.10.037

Reactions of 2-(1H-benzimidazol-2-yl)phenol (1) and SnPh₃Cl, SnPh₂Cl₂ and SnCl₄ were investigated. One tetracoordinated triphenyltin(IV) compound: triphenyltin-2-(1H-benzimidazol-2-yl)phenolate] (3) and its addu

Full text of DOI:10.1016/j.jorganchem.2008.10.037

Journal of Organometallic Chemistry 694 (2009) 269–277
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Hypervalent triphenyl and diphenyl tin coordination compounds
derived from 2-(1H-benzimidazol-2-yl)phenol
Adriana Esparza-Ruiz, Adrián Peña-Hueso, Iris Ramos-García, Aurora Vásquez-Badillo,
*
Angelina Flores-Parra , Rosalinda Contreras
Department of Chemistry, Cinvestav (Centro de Investigacion y de Estudios Avanzados), A.P. 14-740, 07000 México D.F., Mexico
a r t i c l e i n f o
a b s t r a c t
Article history:
Reactions of 2-(1H-benzimidazol-2-yl)phenol (1) and SnPh3Cl, SnPh2Cl2 and SnCl4 were investigated. One
tetracoordinated triphenyltin(IV) compound: triphenyltin-2-(1H-benzimidazol-2-yl)phenolate] (3) and
its adducts: [O ? Sn] dimethylsulfoxide triphenyltin-[2-(1H-benzimidazol-2-yl)phenolate] (4),
[O ? Sn] aqua triphenyltin-[2-(1H-benzimidazol-2-yl)phenolate] (5) [O ? Sn] ethanol triphenyltin-[2-
(1H-benzimidazol-2-yl)phenolate] (6), [N ? Sn] pyridine triphenyltin-[2-(1H-benzimidazol-2-yl)pheno-
late] (7), where 1 acts as a monodentate ligand bound through the phenol oxygen, were obtained. In the
pentacoordinated compounds 4–7, the tin atom has tbp geometry. The three phenyl groups are in equa-
torial positions, whereas the benzimidazole and the Lewis base are in apical positions. Two hexacoordi-
Received 4 September 2008
Received in revised form 22 October 2008
Accepted 22 October 2008
Available online 30 October 2008
Keywords:
2-(1H-benzimidazol-2-yl)phenol
Hypervalent organotin compounds
119Sn NMR
nated tin compounds: diphenyltin-bis[2-(1H-benzimidazol-2-yl-
jN)phenolate-jO] (8), dichlorotin-
bis[2-(1H-benzimidazol-2-yl- N)phenolate- O] (9) bearing two bidentate ligands are reported. The
j
j
coplanar ligands in 8 and 9 form six membered rings by oxygen and nitrogen coordination. The tin geom-
etry is all-trans octahedral. In 8 the two phenyl groups, and in 9 the two chlorine atoms are perpendicular
to the plane of the ligands. Compounds were identified in solution mainly by 1H, 13C and 119Sn NMR and
in the solid state by X-ray diffraction analysis.
Ó 2008 Elsevier B.V. All rights reserved.
1. Introduction
suitable for the synthesis of structurally diverse coordination com-
pounds which are influenced by the strong intramolecular hydro-
We are currently investigating the chemistry of organotin com-
pounds derived from polyfunctional planar aromatic ligands, such
as diphenolamines [1], diphenoloxamides [2–4] and thiolamines
derived from benzimidazole [5,6]. The rigid framework of the aro-
matic ligands allows the synthesis of hypervalent tin compounds
having diverse structures and inter- and intramolecular weak
interactions. The relevance of these compounds is based on their
structure and tin hypervalence, as well as on the wide number of
applications of tin compounds as biocides and plaguicides [7–13]
and antiinflamatories [14] along with the well known biocidal
and pharmacological activities of benzimidazole derivatives [15–
17] and to their potential as anticancer, antibacterial [18,19] or
DNA intercalating agents [20].
gen bond O–HÁ Á ÁN (HÁ Á ÁN distance is 1.63 Å) which affords a
planar tetracyclic structure, as was found in solid state (Scheme
1) [21]. Previous preparation of phosphorus [22] and boron [23]
heterocycles derived from 1 and the tris-chelate cobalt(III) com-
plex obtained by bidentate coordination of 1 [21] suggest that
the reaction of 1 with tin reagents could give the structures de-
picted in Scheme 2. However, their resulting derivatives, described
in Schemes 3 and 5 were not the structures which had been
expected as we will discussed later. Reactions of R2SnX2 (X = OR,
Cl; R = Me, Et, Bu, C6H5) and ligand 1 were previously reported,
however the products were only characterized by elemental anal-
ysis, UV and IR, [24] therefore, a detailed structural analysis was
justified. We have performed the reactions of ligand 1 with
(C6H5)3SnCl, (C6H5)2SnCl2 and SnCl4, and the corresponding
characterizations of the products were carried out by NMR and
X-ray diffraction.
2. Results and discussion
2.1. General comments
2.2. Reaction of 1 with SnPh3Cl
Herein we report a series of tin derivatives of 2-(1H-ben-
zimidazol-2-yl)phenol (1). The ligand is a polyfunctional molecule
The equimolar reaction of SnPh3Cl with the sodium salt (2) of
compound 1 was performed in dry THF. The (THF-d8) solution of
the reaction product
À88.5 ppm, which corresponded to a tetracoordinated Sn(Ph)3OR
3 presented a
119Sn NMR signal at
* Corresponding author. Tel.: +55 5061 3720; fax: +55 5061 3389.
E-mail address: aflores@cinvestav.mx (A. Flores-Parra).
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2008.10.037

270
A. Esparza-Ruiz et al. / Journal of Organometallic Chemistry 694 (2009) 269–277
was also observed in the 13C spectrum which showed only three
H
signals for the phenylene carbons atoms [C4–C7 (114.4); C5–C6
(122.3) and C8–C9 (137.9 ppm)]. The N–H bond dissociation and
tautomerism could be assisted by the O–H hydrogen bond, pro-
moting the C2–C10 bond rotation, and the exchange of the N1
and N3 positions, Scheme 4.
Lewis base additions (DMSO, H2O/DMSO, EtOH, or pyridine) to
compound 3 resulted in the corresponding pentacoordinated com-
pounds 4–7 (Scheme 3) which were analyzed in solution. The 119Sn
N
N
H
O
Scheme 1. 2-(1H-benzimidazol-2-yl)phenol (1).
tin atom, as it was confirmed by comparison with Sn(Ph)3O-1-
naphtyl (À91.8 ppm) [25,26]. The chemical shift indicated that
the reaction involved the substitution of the OH proton by the
tin atom and that N ? Sn coordination was absent, which was con-
firmed by comparison with the 119Sn resonance (À189.9 ppm) of a
pentacoordinated tin derivative of Sn(Ph)3-8-hydroxyquinoline
where a similar O–Sn bond was formed together with a strong
intramolecular N ? Sn coordination [25,26]. An explanation for
the lack of N ? Sn intramolecular coordination in compound 3
was found in the strong hydrogen bond between the N–H and
the oxygen of the O-SnPh3 group, which stabilizes the tautomer
with the N-lone pair on the opposite side to the tin coordination,
Scheme 3. The tin resonance of compound 3 in THF showed that
THF was not significantly coordinated to the tin atom at room
temperature.
1
1
N
N
10
2
N
N
3
3
H
O
H
O
C6H5
C6H5
Sn
C6H5
C6H5
Sn
H5C6
H5C6
3
3
N
N
The structure of 3 was confirmed by its 1H spectrum (dry THF-
d8) which showed the N–H proton at 12.62 ppm and by the 13C
spectrum where the C10, C11 and C12 signals were shifted to high-
er frequencies when compared with those of 1, due to the O–Sn
bond formation. The simplicity of benzimidazole protons in the
1H spectrum of 3 at room temperature [one signal at 7.80 ppm
for H4 and H7 and another at 7.15 ppm for H5 and H6] indicated
the fast N–H tautomerism between N1 and N3. This phenomenon
2
10
N
N
1
1
H
O
H
O
C6H5
C6H5
Sn
C6H5
C6H5
Sn
H5C6
H5C6
Scheme 4. Proton tautomerism in compound 3.
H
N
N
N
N
N
N
Sn
O
Sn
O
Sn
O
C6H5
C6H5
O
C6H5
C6H5
C6H5
N
N
Scheme 2. Expected compounds derived from ligand 1 and Ph3SnCl, Ph2SnCl2 and SnCl4.
¨
N
¨
N
N
H
1
N
15
14
1) NaH
2) (C6H5)3SnCl
H
O
N
B
C6H5
C6H5
2
10
16
13
Sn
H5C6
H
O
3
N
THF
12
11
.
.
C6H5
C6H5
Sn
B
HO
H5C6
4 B = DMSO
5 B = OH2
3
6 B = EtOH
7 B = Py
Scheme 3. Tin compounds synthesized from ligand 1 and Ph3SnCl.

A. Esparza-Ruiz et al. / Journal of Organometallic Chemistry 694 (2009) 269–277
271
H
N
1) 2NaH
2) (C6H5 )2SnCl2
O
N
H
N
Sn
N
H
N
2
O
N
THF
H
O
Scheme 5. Synthesis of compound 8.
NMR spectrum of compound 3 dissolved in anhydrous DMSO gave
a signal at À265.5 ppm, for the DMSO coordinated compound 4. A
similar experiment in wet DMSO, showed two signals (À227.8 and
À265.5 ppm), where the second one was assigned to 4, and the first
to the coordinated water compound 5. Addition of ethanol gave
119Sn resonance at À573 ppm, characteristic of a hexacoordinated
tin atom. The elemental analysis and the TOF high resolution mass
spectrum [MS(TOF), Calc. (C32H23N4O2Sn)+ 615.0837 amu. Exp.
615.0848 amu (error = 1.7 ppm)] showed that compound 8 con-
tains a tin atom with two deprotonated benzimidazole ligands
and two phenyl groups, Scheme 5. From different THF solutions
crystals of two polymorphs of 8 were obtained and analyzed by
X-ray diffraction [polymorph 8a is monoclinic, (P21) whereas 8b
complex
6
(À223.2 ppm) and pyridine afforded complex
7
(À218.8 ppm), Table 1. The tin pentacoordination was also con-
firmed from the coupling constants values 1J(119/117Sn–13C) =
786.4/753.3 Hz measured at the 13C spectrum of 6. The 1H spectra
of compounds 4–7 showed the characteristic hydrogen bound N–H
signals [12.62 to 13.25 ppm], Table 1.
ꢀ
is triclinic (P1)].
Both polymorphs contain one molecule of 8 and two of THF. The
tin atom is hexacoordinated with all-trans octahedral geometry.
Four of the six positions are occupied by two bidentate planar li-
gands bound by the oxygen and one nitrogen and lie in the same
plane. The two other positions are occupied by two phenyl groups
perpendicular to the plane of the ligands, Fig. 5. The tin bonds
lengths: Sn–O (ꢀ2.11 Å), and Sn–C (ꢀ2.17 Å) are characteristic of
covalent bonds, whereas Sn–N (ꢀ2.28 Å) correspond to strong
coordination bonds, Scheme 5. The molecule is rigid due to the
Compounds 4–7 afforded suitable crystals for X-ray diffraction
analyses, Fig. 1. In all structures, the tin atom is pentacoordinated
with tbp geometry. The three phenyl groups are in equatorial posi-
tions, whereas the benzimidazole and the Lewis base are in apical
positions. The ligand presented two intramolecular hydrogen
bonds (N–HÁ Á ÁO and C–HÁ Á ÁN) which maintain its planar conforma-
tion. All the crystals were of good quality, except compound 4
which was poor. However the structure was determined with clar-
ity. The crystal data for compounds 4–6 and for 7–8 are in Tables 2
and 3, respectively. Selected bond lengths and angles for 4–7 are in
Table 4 and for 8 in Table 5.
p-delocalization and cooperative intramolecular hydrogen bonds.
Each phenol oxygen atom becomes pentacoordinated due to its
hydrogen bonds to three C–H groups, Fig. 6. The acidic N–H pro-
tons are bound to the THF oxygen (2.15 Å), Fig. 7.
Intermolecular interactions are observed in 5, formed through
the H2O molecule coordinated to tin, Fig. 2. The crystal lattice of
6 shows intramolecular HÁ Á ÁO bonds and an intermolecular N1
H36 bond [2.10(5) Å] forms a polymer, Fig. 3. Compound 7
crystallized with two independent molecules [7a and 7b] in the
asymmetric cell which differs slightly in the Sn–Ph bonds confor-
mations, Fig. 4.
Crystals of compound 8 are insoluble in polar and non polar
solvents, therefore, their characterization in solution was per-
formed before its precipitation or crystallization. An explanation
for this insolubility could be found in the crystal packing of 8,
where the ligands form a staircase framework stabilized by inter-
molecular p-stacking with other molecules. The Sn-phenyl groups
contribute to the close packing of the molecules by C–HÁ Á Á
p-
interactions, The oxygen atoms of the THF molecules form bifur-
cated hydrogen bonds with the ligands covering the labile pro-
tons of the molecules, therefore the crystals offer C–H and
aromatic rings surfaces which could explain the crystals insolubil-
ity, Figs. 7 and 8.
2.3. Reaction of 1 with SnPh2Cl2
The sodium anion of ligand 1 was reacted with a half equivalent
of Ph2SnCl2. The 119Sn spectrum of the reaction mixture showed a
Table 1
119Sn, 1H and 13C selected NMR Data (d, ppm) of compounds 3–7.
Compound
d
119Sn
d
1H
d
13Ci
d
13Co
d
13Cm
d
13Cp
{solvent}
[1J(13C,119/117Sn)]
[2J(13C,119/117Sn)]
[3J(13C,119/117Sn)]
[4J(13C,119Sn)]
(C6H5)3SnCl
À47.0
{CDCl3}
À226.8
–
–
–
136.2
[613.8/586.4]
143.8
[810.6]
143.3
[783.2]
140.5
134.2
[49.3]
136.1
[47.9]
137.0
[45.9]
136.4
[44.6]
136.1
[43.9]
136.1
[43.9]
136.1
[46.9]
136.6
[43.7]
130.6
[64.3/61.7]
128.5
[71.3]
129.1
[70.3]
128.4
133.4
[13.4]
129.1
[14.6]
129.8
[14.6]
129.3
(C6H5)3SnCl
{DMSO-d6}
À 203.5
{pyridine}
À88.5
(C6H5)3SnCl
3
4
5
6
7
N–H 12.62
N–H 13.25
{THF-d8}
À265.5
142.1
142.1
128.9
128.9
129.5
129.5
128.9
130.0
{DMSO-d6}
À227.8
O–H 11.84
N–H 13.25
O-H 11.51
N–H 12.78
N–H 12.62
{DMSO-d6}
À223.2
142.9
[786.4/753.3]
140.2
128.2
[69.2]
129.1
[67.9]
{CDCl3}
À218.8
{CDCl3}

272
A. Esparza-Ruiz et al. / Journal of Organometallic Chemistry 694 (2009) 269–277
Fig. 1. ORTEP diagrams for compounds 4–7.
2.4. Reaction of 1 with tin tetrachloride
SnPh2Cl2 and SnCl4 reactions afford molecules with two coplanar
benzimidazoles, where the tin is included in the plane of the li-
gands. The coordination produces six membered rings. The hexaco-
ordinated tin has all-trans octahedral geometry.
One equivalent of SnCl4 was added to two equivalents of the so-
dium anion of ligand 1 dissolved in THF at À60 °C, and then stirred
at room temperature for three days. From the solution, the 119Sn
spectrum showed a signal for a hexacoordinated compound 9
(À614 ppm). The solvent was evaporated and a very insoluble
white powder was obtained which was purified by washing with
water, THF and MeOH. The elemental analysis of the solid corre-
sponds to a molecule with two deprotonated ligands, a tin and
two chlorine atoms. Some crystals were formed in a THF solution
after the addition of a few drops of DMSO. The structure of com-
pound 9 was determined even though the crystal was disordered.
Compound 9 is similar to 8. In 9 the two Sn–Cl bonds atoms are
perpendicular to the plane formed by the benzimidazoles, Fig. 9.
The quality of the crystals prevents the reporting of accurate angles
and bond lengths.
4. Experimental
4.1. General comments
Vacuum line techniques were employed for all manipulations of
air and moisture sensitive compounds. THF was dried by distilla-
tion from Na-benzophenone under a N2 atmosphere prior to use.
Dry CDCl3, DMSO-d6, THF-d8, SnPh3Cl, SnPh2Cl2 and SnCl4 were
purchased from Aldrich and used without further purification.
The melting points were obtained on a Mel-Temp II apparatus
and are uncorrected. Mass spectra in the EI mode were recorded
at 20 eV on a Hewlett–Packard HP 5989 spectrometer. High resolu-
tion mass spectra were obtained by LC/MSD TOF on an Agilent
Technologies instrument with APCI as ionization source. Elemental
analyses were performed on Eager 300 or on Flash 1112 Thermo
Finnigan equipment. NMR spectra were obtained on a Jeol GSX-
270, Jeol Eclipse 400 MHz and Bruker Advance 300 MHz. 1H, 13C
3. Summary
Expected compounds, in Scheme 2, were not found, and in their
place five new triphenyltin compounds were synthesized, where 1
acts as a monodentate ligand, bound through the phenol oxygen.
The monodentate benzimidazole forms a planar tetracyclic struc-
ture, due to the strong intramolecular N–HÁ Á ÁO hydrogen bond.
Compound 3 in dry THF is tetracoordinated. It is very reactive
and in the presence of Lewis bases or water traces gives the H2O,
EtOH, DMSO and pyridine pentacoordinated tin adducts 4–7.
[
[
N
N
25.145020, Si(CH3)4], 15N [
N
10.136767, CH3NO2] and 119Sn
= 37.290 Sn(CH3)4]. 119Sn spectra were obtained by single pulse
with broad decoupling experiments. The assignment of 1H and 13
C
data were based on 2D experiments: 1H/1H COSY, 1H/13C HETCOR
and 1H/13C COLOC. IR spectra were obtained in KBr disc using a
FT Spectrum GX Perkin–Elmer spectrometer.

A. Esparza-Ruiz et al. / Journal of Organometallic Chemistry 694 (2009) 269–277
273
Table 2
Crystal data and structure refinement for compounds 4–6.
Compounds
4
5
6
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
a (Å)
C33H30N2O2SSn
637.37
293
0.71073
Monoclinic
P21/c
10.0488 (3)
30.0103 (10)
10.0271 (4)
90
99.893 (2)
90
2978.88 (18)
4
1.421
C35H34N2O3Sn
649.36
293
0.71073
Monoclinic
P21/n
10.18670 (10)
19.2769 (3)
15.8509 (3)
90
91.7559 (7)
90
3111.15 (8)
4
1.386
C33H30N2O2Sn
605.3
293
0.71073
Triclinic
ꢀ
P1
9.80120 (10)
10.7383 (2)
15.9763 (3)
71.6371 (7)
77.2214 (7)
62.9023 (7)
1414.66 (4)
2
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
Volume (Å3)
Z
Calculated
(mmÀ1
F(000)
q
(mg/m3)
1.421
0.94
616
l
)
0.96
1296
0.86
1328
Crystal size (mm)
Crystal color
h range
0.5 Â 0.05 Â 0.05
Colourless prism
2.057–28.378
À12 ꢁ h ꢁ 12;
À39 ꢁ k ꢁ 33;
À20 ꢁ l ꢁ 20
11352
0.3 Â 0.2 Â 0.15
Light brown prism
2.571–27.859
À11 ꢁ h ꢁ 13;
À13 ꢁ l ꢁ 13
À13 ꢁ k ꢁ 13;
39453
0.5 Â 0.5 Â 0.2
Orange prism
3.408–27.465
À12 ꢁ h ꢁ 12;
À25 ꢁ k ꢁ 22;
À19 ꢁ l ꢁ 20
23525
Limiting indices
Reflections collected
Independent reflections
6644
7400
6370
[R(int)
]
0.125
0.07
0.032
Completeness to h
Observed reflections
Tmax, Tmin
25.3°, 96.8%
2173
0.9532, 0.9532
0.7652
27.9°, 99.7%
3219
0.88, 0.85
1.0979
25.8°, 99.5%
5353
0.83, 0.76
1.0684
Goodness-of-fit (GOF) on F2
R (all data)
0.3189
0.0838
0.0343
wR (all data)
0.3579
0.0565
0.0417
Final R1
0.1222 (I > 2.5
r
)
0.0249 (I > 3.0
r)
0.0268 (I > 3.0r)
Final wR2
0.1279
0.0285
0.036
Table 3
Crystal data and structure refinement for compounds 7–8.
Compounds
7
8a
8b
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
a (Å)
C36H29N3OSn
638.34
293
0.71073
Monoclinic
Pn
9.7034 (2)
17.6907 (3)
17.4471 (3)
90
93.7878 (7)
90
2988.43 (10)
4
1.419
0.89
C38H28N4O2Sn Á 2(C4H8O)
835.57
293
0.71073
Monoclinic
P21
9.7634 (2)
20.7618 (3)
9.7963 (2)
90
92.9310 (10)
90
1983.17 (6)
2
1.399
0.69
C38H28N4O2Sn Á 2(C4H8O)
835.57
293
0.71073
Triclinic
ꢀ
P1
9.7521 (3)
9.7643 (3)
10.4988 (4)
87.6687 (15)
85.8673 (15)
87.0848 (15)
995.14 (6)
1
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
Volume (Å3)
Z
Calculated
(mmÀ1
F(000)
q
(mg/m3)
1.394
0.69
430
l
)
1296
860
Crystal size (mm)
Crystal color
h range
0.2 Â 0.17 Â 0.1
Light brown prism
3.447–27.504
À12 ꢁ h ꢁ 12;
À22 ꢁ k ꢁ 22;
À12 ꢁ l ꢁ 12
13205
0.15 Â 0.08 Â 0.08
Colorless prism
3.48–27.489
À12 ꢁ h ꢁ 12;
À22 ꢁ l ꢁ 22
À13 ꢁ k ꢁ 13;
8781
0.23 Â 0.15 Â 0.12
Colorless prism
1.946–30.411
À10 ꢁ h ꢁ 13;
À24 ꢁ k ꢁ 26;
À14 ꢁ l ꢁ 13
14285
Limiting indices
Reflections collected
Independent reflections
12973
8781
5167
[R(int)
]
0.024
0
0.087
Completeness to h
Observed reflections
Tmax, Tmin
26.7°, 99.5%
8084
0.915, 0.8561
1.018
25.6°, 98.8%
6344
0.946, 0.946
1.0211
26.8°, 96.4%
2315
0.92, 0.65
1.0284
Goodness-of-fit (GOF) on F2
R (all data)
0.0788
0.0701
0.1106
wR (all data)
0.0504
0.0659
0.1169
Final R1
0.0359 (I > 3.0
r)
0.0403 (I > 3.0
r)
0.0468 (I > 3.0r)
Final wR2
0.0367
0.0454
0.0603

274
A. Esparza-Ruiz et al. / Journal of Organometallic Chemistry 694 (2009) 269–277
Table 4
Table 5
Selected bond lengths (Å) and angles (°) for compounds 4–7.
Selected bond lengths (Å) and angles (°) for compound 8.
Bond lengths
4
5
6
7a
7b
Bond lengths
8a
8b
C2–N1
C2–N3
C8–N1
C9–N3
C18–Sn
C24–Sn
C30–Sn
O(N)36–Sn
O16–Sn
1.31(2)
1.39(3)
1.39(3)
1.40(3)
2.11(2)
2.13(2)
2.15(2)
2.32(1)
2.12(1)
1.330(4)
1.367(4)
1.386(5)
1.372(4)
2.129(4)
2.126(4)
2.122(3)
2.349(2)
2.125(2)
1.333(3)
1.355(4)
1.388(4)
1.372(4)
2.132(3)
2.122(3)
2.123(3)
2.505(2)
2.105(2)
1.330(7)
1.351(8)
1.396(7)
1.385(9)
2.114(7)
2.126(6)
2.112(6)
2.559(5)
2.101(4)
1.330(8)
1.351(8)
1.385(8)
1.362(9)
2.127(8)
2.122(7)
2.117(7)
2.541(6)
2.113(5)
Sn–O16
Sn–O30
Sn–N3
Sn–N39
Sn–C18
Sn–C24
2.114(4)
2.105(4)
2.284(4)
2.288(4)
2.167(5)
2.152(5)
2.112(4)
2.299(4)
2.176(6)
Bond angles
N3–Sn–O16
N3–Sn–C18
O16–Sn–C18
N3–Sn–C24
O16–Sn–C24
C18–Sn–C24
N3–Sn–O30
O16–Sn–O30
C18–Sn–O30
C24–Sn–O30
N3–Sn–N39
O16–Sn–N39
C18–Sn–N39
C24–Sn–N39
O30–Sn–N39
8a
8b
83.3(2)
90.6(2)
90.0(2)
88.7(2)
88.7(2)
178.6(2)
95.9(2)
179.2(2)
89.9(2)
91.4(2)
178.0(5)
98.7(4)
89.3(2)
91.4(2)
82.1(4)
82.8(2)
91.0(2)
91.4(2)
89.0(2)
88.6(2)
179.9(1)
97.2(2)
179.9(1)
88.6(2)
91.4(2)
179.9(1)
97.2(2)
89.0(2)
91.0(2)
82.8(2)
Bond angles
4
5
6
7a
7b
O(N)36–Sn–C30
O(N)36–Sn–C24
C30–Sn–C24
87.8(6)
87.3(6)
118.9(8)
90.1(1)
86.3(1)
86.4(1)
84.07(9)
121.1(1)
174.39(8)
87.98(9)
98.7(1)
86.93(9)
118.5(1)
118.8(1)
95.88(9)
83.2(2)
86.2(2)
122.7(2)
173.1(2)
89.9(2)
97.3(2)
86.1(2)
113.7(2)
121.5(2)
96.9(2)
84.6(2)
86.8(2)
117.7(3)
172.9(2)
88.3(2)
96.0(2)
84.1(2)
115.9(3)
124.4(3)
99.5(2)
125.0(1)
176.5(1)
86.8(1)
94.2(1)
86.9(1)
113.3(1)
121.2(2)
95.8(1)
O(N)36–Sn–O16 176.0(5)
C30–Sn–O16
C24–Sn–O16
O(N)36–Sn–C18
C30–Sn–C18
C24–Sn–C18
O16–Sn–C18
88.3(6)
94.2(6)
83.2(7)
118.4(8)
121.4(8)
99.1(7)
4.2. Syntheses
4.2.1. Triphenyltin [2-(1H-benzimidazol-2-yl)phenolate] (3)
Compound 1 (200 mg, 0.95 mmol) and NaH (26 mg, 1.08 mmol)
were dissolved in dry THF (40 mL) and the reaction mixture was
stirred for 1 h at r.t., then (C6H5)3SnCl (367 mg, 0.95 mmol) was
added and the mixture stirred for 12 h. It was filtered and the sol-
vent evaporated under vacuum. A light brown crystalline powder
was obtained which corresponded to compound 3. NMR (THF-
d8), d (ppm), 1H: 7.80 (2H, H-4, H-7), 7.15 (2H, H-5, H-6), 6.86
(H-12), 7.45 (H-13), 6.79 (H-14), 7.95 (H-15), 12.62 (N–H); [SnPh3]
group: 7.50 (6H, Ho), 7.36 (6H, Hm), 7.35 (3H, Hp). 13C: 152.4 (C2),
114.4 (C4, C7), 122.3 (C5, C6), 137.9 (C8, C9), 114.5 (C10), 160.1
(C11), 118.3 (C12), 131.0 (C13), 118.3 (C14), 126.0 (C15); SnPh3
group: 140.9 (3Ci), 136.4 (6Co), 128.4 (6Cm), 129.3 (3Cp).
Fig. 2. Interactions in the lattice of 5. [Distances: O16Á Á ÁH3 = 2.09 Å,
O37Á Á ÁH361 = 1.86(4) Å, N1Á Á ÁH362 = 1.96(5) Å and C26Á Á ÁH14 = 2.85 Å].
4.2.2. [O ? Sn] dimethylsulfoxide triphenyltin-[2-(1H-benzimidazol-
2-yl)phenolate] (4)
Compound 3 was dissolved in DMSO-d6, and the adduct 4 char-
acterized by NMR. From the NMR tube, crystals suitable for X-ray
diffraction analyses were formed. NMR (DMSO-d6), d (ppm). 1H:
7.87 (2H, H-4, H-7), 7.10 (2H, H-5, H-6), 6.60 (H-12), 6.75 (H-13),
6.65 (H-14), 8.13 (H-15), 11.92 (N–H); [SnPh3] group: 7.55 (6H,
Ho), 7.36 (9H, 6Hm and 3Hp). 13C: 152.1 (C2), 114.4 (C4, C7),
121.3 (C5, C6), 136.7 (C8, C9), 161.9 (C11), 120.0 (C12), 130.2
(C13), 118.0 (C14), 128.2 (C15); SnPh3 group: 142.1 (3Ci), 136.1
(6Co), 128.9 (6Cm), 129.4 (3Cp).
4.2.3. [O ? Sn] aqua triphenyltin-[2-(1H-benzimidazol-2-yl)-
phenolate] (5)
Compound 3 (100 mg) was slowly crystallized in 20 mL of wet
THF (3 weeks) to give brown pale crystals, (82 mg, 80%). At
148 °C crystals lost solvent, they solidify again at 168 °C, and do
not melt below 340 °C. NMR (DMSO-d6), d (ppm), 1H: 7.87 (2H,
H-4, H-7), 7.10 (2H, H-5, H-6), 6.60 (H-12), 6.75 (H-13), 6.65

A. Esparza-Ruiz et al. / Journal of Organometallic Chemistry 694 (2009) 269–277
275
Fig. 3. Some H-bonds in the lattice of 6. [Distances: O16Á Á ÁH3 = 2.19(4) Å,
O16Á Á ÁH23 = 2.62(4) Å, O36Á Á ÁH19 = 2.59(5) Å and N1Á Á ÁH36 = 2.10(5) Å].
Fig. 6. Intramolecular interactions of compound 8.
1603 (C@N), 731 (SnÀO). Anal. Calc. for C31H24N2OSn Á THF Á 2H2O:
C, 63.00; H, 5.44; N, 4.20. Found: C, 63.36; H, 5.41; N, 3.98%.
4.2.4. [O ? Sn] ethanol triphenyltin-[2-(1H-benzimidazol-2-yl)-
phenolate] (6)
Compound 3 (100 mg) dissolved in EtOH afforded colorless
crystals (85 mg, 79%). Dec at 310 °C. M.S.: m/z (%): 605(0.1) [M]+,
559(1.1) [MÀEtOH]+, 210(100) [MÀSnPh3EtOH]+. IR (KBr,
m
cmÀ1): 1653 (C@N), 733 (Sn–O). NMR (CDCl3), d (ppm) 1H: 7.72
(2H, H-4, H-7), 7.12 (2H, H-5, H-6), 6.59 (H-12), 6.95 (H-13), 6.61
(H-14), 8.13 (H-15), 12.78 (N–H); SnPh3 group: 7.92 (6H, Ho),
7.34 (6H, Hm) 7.33 (3H, Hp); EtOH: 3.60 (2H, CH2), 0.88 (3H, CH3),
11.51 (1H, OH). 13C: 152.5 (C2), 114.2 (C4, C7), 122.3 (C5, C6),
136.8 (C8, C9), 114.4 (C10), 160.8 (C11), 119.0 (C12), 130.9 (C13),
117.2 (C14), 126.9 (C15); SnPh3 group: 142.9 (3Ci), 136.1 (6Co),
128.2 (6Cm), 128.9 (3Cp); EtOH: 57.4 (CH2), 18.2 (CH3). Anal. Calc.
for C31H24N2OSn Á C2H6O: C, 65.48; H, 5.00; N, 4.63. Found: C,
65.03; H, 5.20; N, 4.41%.
Fig. 4. ORTEP diagram of 7a (right) and 7b (left).
4.2.5. [N ? Sn] pyridine triphenyltin-[2-(1H-benzimidazol-2-yl)-
phenolate] (7)
To a solution of 3 (100 mg) in THF (10 mL) two equivalents of
dried pyridine were added and the solution was kept aside for few
days. Brown pale crystals were obtained (90 mg, 82%,). M.S.: m/z
(%): 482(0.1) [MÀPy and Ph]+, 405(0.1) [MÀPy and 2Ph]+,
351(17.0) [MÀL]+, 210(6.0) [MÀPh3Sn]+, 78(100) [MÀLPh3Sn]+.
IR (KBr,
m
cmÀ1): 1620 (C@N), 739 (Sn–O), 545 (Sn–C), 455 (Sn–
N). NMR (CDCl3), d (ppm) 1H: 7.77 (2H, H-4, H-7), 7.16 (2H, H-5,
H-6), 6.62 (H-12), 6.96 (H-13), 6.63 (H-14), 8.25 (H-15), 12.62
(N–H); SnPh3 group: 7.72 (6H, Ho), 7.40 (6H, Hm), 7.45 (3H, Hp);
[Py]: 8.39 (2H, Ho), 7.27 (2H, Hm), 7.70 (1H, Hp). 13C: 153.1 (C2),
114.7 (C4, C7), 122.1 (C5, C6), 140.29 (C8, C9), 116.8 (C10),
161.4 (C11), 120.0 (C12), 131.0 (C13), 117.9 (C14), 128.1 (C15);
SnPh3 group: 140.2 (3Ci), 136.6 (6Co), 129.1 (6Cm), 130.0 (3Cp);
[Py]: 149.4 (2Co), 124.3 (2Cm), 137.1 (Cp). Anal. Calc. for
C36H29N3OSn: C, 67.74; H, 4.58; N, 6.58. Found: C, 67.60; H,
4.44; N, 6.44%.
Fig. 5. ORTEP diagram of 8.
4.2.6. Diphenyltin-bis[2-(1H-benzimidazol-2-yl-jN)phenolate-jO]
(8)
To a solution of 1 (250 mg, 1.2 mmol) in 40 mL of THF, NaH was
added (68 mg, 2.8 mmol). The reaction mixture was stirred for 2 h.
Then Ph2SnCl2 (145 mg, 0.6 mmol) was added and the mixture was
stirred for 3 days. The soluble phase in THF was evaporated under
(H-14), 8.13 (H-15), 13.25 (N–H); SnPh3 group: 7.55 (6H, Ho), 7.36
(9H, 6Hm and 3Hp); H2O: 11.51 (2H). 13C: 152.1 (C2), 114.4 (C4, C7),
121.3 (C5, C6), 136.7 (C8, C9), 114.5 (C10), 161.9 (C11), 120.0 (C12),
130.2 (C13), 118.0 (C14), 128.2 (C15); SnPh3 group: 142.1 (3Ci),
136.1 (6Co), 128.9 (6Cm), 129.4 (3Cp). M.S.: m/z (%): 560(0.1)
[MÀH2O], 483(0.3) [MÀPh], 351(100) [MÀL]. IR (KBr,
m
cmÀ1):

276
A. Esparza-Ruiz et al. / Journal of Organometallic Chemistry 694 (2009) 269–277
Fig. 7. Intermolecular interactions in the crystal of 8b.
Fig. 8. Close staircase packing in compound 8b.
Fig. 9. Views of the crystalline structure of compound 9.
vacuum to give a light brown powder which after crystallization in
4.2.7. Dichlorotin-bis[2-(1H-benzimidazol-2-yl-jN)phenolate-jO] (9)
THF, affords colorless crystals. Dec ꢂ 300 °C. NMR (THF-d8): d 119Sn
To a solution of 1 (500 mg, 2.4 mmol) in 60 mL of THF, NaH was
added (69 mg, 2.9 mmol). The reaction mixture was stirred for 2 h
and cooled to À60 °C and SnCl4 (0.14 mL, 1.2 mmol) was added.
The mixture was stirred for 3 days at r.t., then the solvent was
evaporated under vacuum. A white powder was obtained, that
À573. IR (KBr,
m
cmÀ1): 1604 (C@N), 747 (Sn–O), 455 (Sn–N). M.S.
(TOF), Calc. (C32H23N4O2Sn)+ 615.0837 amu. Exp. 615.0848 amu
(error = 1.7 ppm). Anal. Calc. for C38H28N4Sn Á 2THF Á 2H2O: C,
63.39; H, 5.55; N, 6.43. Found: C, 63.29; H, 5.24; N, 6.04%.

A. Esparza-Ruiz et al. / Journal of Organometallic Chemistry 694 (2009) 269–277
277
was washed with water, THF and MeOH. M.p. > 400 °C. IR (KBr,
m
References
cmÀ1): 1605 (C@N), 1246 (C–O), 750 (Sn–O). Anal. Calc. for
C26H18N4O2SnCl2 Á 2H2O: C, 48.49; H, 3.44; N, 8.70. Found: C,
48.46; H, 3.49; N, 8.41%.
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Financial support from Conacyt-Mexico and Cinvestav is
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