Syntheses and characterizations of di- and tri-organotin carboxylates of 4-oxo-4-phenyl butanoic and 4-(4-biphenyl)-4-oxobutyric acid

Article abstract of DOI:10.1080/00958972.2012.724680

A family of organotin carboxylates, [(C₆H₅) ₃Sn(L¹)₂] (1) and [(C₆H ₁₁)₂Sn(L²)] (2), was synthesized from reaction of R′₃SnOH and (where R=phenyl, R′=cyclohexyl) with 4-oxo-4-phenyl butanoic (L¹H) and 4-(4-biphenyl)-4-oxobutyric acid (L²H) in suitable mole ratios. They have been characterized by elemental analysis, FT-IR, ¹H NMR spectroscopy, and single-crystal X-ray diffraction analysis. In 1, the geometry of tin is trigonal bipyramidal. Supramolecular architecture of 1 shows a polymeric chain structure with Ph3Sn centers linked by PhCOC₂H₄CO₂ ligands via O→Sn interactions. SnSn non-bonded distances in the repeating 1-D polymeric structure equal 5.835 A. Complex 2 contains an angular sector and adopts a distorted tetrahedral geometry.

Full text of DOI:10.1080/00958972.2012.724680

Journal of Coordination Chemistry
ISSN: 0095-8972 (Print) 1029-0389 (Online) Journal homepage: http://www.tandfonline.com/loi/gcoo20
Syntheses and characterizations of di- and tri-
organotin carboxylates of 4-oxo-4-phenyl butanoic
and 4-(4-biphenyl)-4-oxobutyric acid
Adama Moussa Sakho , Moussa Diarso , Lounceny Traore & Dongsheng Zhu
To cite this article: Adama Moussa Sakho , Moussa Diarso , Lounceny Traore & Dongsheng
Zhu (2012) Syntheses and characterizations of di- and tri-organotin carboxylates of 4-oxo-4-
phenyl butanoic and 4-(4-biphenyl)-4-oxobutyric acid, Journal of Coordination Chemistry, 65:21,
3860-3868, DOI: 10.1080/00958972.2012.724680
To link to this article: http://dx.doi.org/10.1080/00958972.2012.724680
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Date: 31 May 2016, At: 05:34

Journal of Coordination Chemistry
Vol. 65, No. 21, 10 November 2012, 3860–3868
Syntheses and characterizations of di- and tri-organotin
carboxylates of 4-oxo-4-phenyl butanoic and
4-(4-biphenyl)-4-oxobutyric acid
ADAMA MOUSSA SAKHO*y, MOUSSA DIARSOz,
LOUNCENY TRAOREx and DONGSHENG ZHU{
yDepartment of Chemistry, Gamal Abdel Nasser University, Conakry 1147,
Republic of Guinea
zInstitution of Genetics and Cytology School of Life Sciences,
Northeast Normal University, Changchun 130024, P.R. China
xDepartment of Chemical Engineering, Gamal Abdel Nasser University,
Conakry 1147, Republic of Guinea
{Department of Chemistry, Northeast Normal University,
Changchun 130024, P.R. China
(Received 10 April 2012; in final form 10 August 2012)
A family of organotin carboxylates, [(C6H5)3Sn(L1)2] (1) and [(C6H11)2Sn(L2)] (2), was
synthesized from reaction of R3SnOH and R02SnO (where R ¼ phenyl, R0 ¼ cyclohexyl) with
4-oxo-4-phenyl butanoic (L1H) and 4-(4-biphenyl)-4-oxobutyric acid (L2H) in suitable mole
ratios. They have been characterized by elemental analysis, FT-IR, 1H NMR spectroscopy, and
single-crystal X-ray diffraction analysis. In 1, the geometry of tin is trigonal bipyramidal.
Supramolecular architecture of 1 shows a polymeric chain structure with Ph3Sn centers linked
by PhCOC2H4CO2 ligands via O ! Sn interactions. Snꢀ ꢀ ꢀSn non-bonded distances in the
˚
repeating 1-D polymeric structure equal 5.835 A. Complex 2 contains an angular sector and
adopts a distorted tetrahedral geometry.
Keywords: Organotin carboxylate; 4-Oxo-4-phenyl butanoic; 4-(4-Biphenyl)-4-oxobutyric acid;
Synthesis; Crystal structure
1. Introduction
Chemical structures and biological activities of organotin carboxylate compounds have
attracted attention for their antitumor activity, antineoplastic, antituberculosis agents,
diversity of structures, and industrial and agricultural applications [1–5].
Various organotin carboxylates can be obtained, such as monomers, dimers,
tetramers, oligomeric ladders, and hexameric drums, utilizing different stoichiometries
of organotin and the carboxylic acid [6]. Antifungal and antitumor activities of
organotin complexes are influenced by the coordination number of tin and the structure
*Corresponding author. Email: adamsacko@yahoo.fr
Journal of Coordination Chemistry
ISSN 0095-8972 print/ISSN 1029-0389 online ß 2012 Taylor & Francis
http://dx.doi.org/10.1080/00958972.2012.724680

Di- and tri-organotin carboxylates
3861
of the molecule [7]. The 4-(4-biphenyl)-4-oxobutyric acid (Fenbufen) is a non-steroidal
anti-inflammatory drug used in the treatment of inflammations such as osteoarthritis,
ankylosing spondylitis, and tendinitis. It is also an antipyretic. Therapeutic properties
of Fenbufen can be attributed to its inhibiting action to cyclooxygenase which is
responsible for the biosynthesis of prostaglandins. Tian and co-workers carried out
elegant work on some organotin carboxylates by the use of Fenbufen as ligand [8].
However, dicyclohexyltin ester based on Fenbufen (L2H) has not been reported. We
recently reported syntheses of organotin carboxylates using 4-oxo-4-phenyl butanoic
acid as ligand reacting with tricyclohexyltin hydroxide. Intermolecular coordination
between oxygen from carbonyl groups and tin was discovered with a distance of
0.7280 nm between tins [9]. As an extension of these studies, now we report syntheses
and characterizations of new organotin(IV) 4-oxo-4-phenyl butanoates,
[(C6H5)3Sn(L1)2] (1) and [(C6H11)2Sn(L2)] (2) (where L1H indicates 4-oxo-4-phenyl
butanoic acid and L2H Fenbufen). The geometry around tin in 1 is distorted trigonal
bipyramidal and the polymeric chain of 1 has a non-bonded distance of [Sn1ꢀ ꢀ ꢀSn1A
˚
and Sn1ꢀ ꢀ ꢀSn1B ¼ (5.835 A)]. Complex 2 shows two monodentate carboxylates and the
structure presents two isosceles triangles around a planar O2SnC2.
2. Experimental
2.1. Materials and methods
Biphenyl, succinic anhydride, dicyclohexyltin oxide, and triphenyltin hydroxide were
purchased from commercial sources, while 4-carbonyl-4-phenyl butanoic acid (L1H)
and Fenbufen (L2H) were prepared according to literature procedures [10]. All
chemicals were used without purification. The solvents were purified before use by
standard procedures. Melting points were obtained by open capillaries and are
uncorrected. 1H NMR spectra were recorded in CDCl3 on a Varian Mercury
300 MHz spectrometer. Infrared (IR) spectra using KBr pellets were recorded on an
Alpha Centauri FT/IR spectrometer (400–4000 cmꢁ1). Elemental analyses were
carried out on a Perkin-Elmer PE 2400 CHN instrument and by gravimetric analysis
for Sn [11].
Single-crystal X-ray diffraction data for 1 and 2 were recorded on a Bruker CCD
˚
diffractometer using the !/’ scan technique with Mo-Ka radiation (ꢀ ¼ 0.71073 A).
Absorption corrections were applied by using multiscan techniques [12]. The structure
was solved by direct methods with SHELXS-97 [13], and refined by full-matrix least
squares with SHELXL-97 [14] within WINGX [15].
All non-hydrogen atoms were refined with anisotropic temperature parameters;
hydrogen atoms were refined as rigid groups. Crystal data and experimental details of
the structure determinations are listed in table 1.
2.2. Syntheses
2.2.1. Synthesis of 4-carbonyl-4-phenyl butanoic acid (L1H). In a three-necked flask,
succinic anhydride (4.003 g, 0.04 mol), anhydrous aluminum chloride (10.67 g,

3862
A.M. Sakho et al.
Table 1. Crystal data and refinement details for 1 and 2.
Empirical formula
Formula weight
Temperature (K)
C
527.16
296(2)
28H24O3Sn
C44H48O6Sn
791.51
293(2)
˚
Wavelength (A)
0.71073
Monoclinic
P21/n
0.71073
Monoclinic
C2/c
Crystal system
Space group
Unit cell dimensions (A, )
ꢂ
˚
a
b
c
ꢃ
ꢄ
ꢅ
12.8831(14)
11.3890(12)
17.0873(18)
90
104.079(2)
90
2431.8(4), 4
1.440
28.417(3)
6.6070(7)
23.608(3)
90
121.149(3)
90
3793.4(7), 4
1.386
3
˚
Volume (A ), Z
Calculated density (Mg mꢁ3
)
Absorption coefficient (mmꢁ1
F(000)
)
1.076
1064
0.721
1064
Crystal size (mm3)
ꢆ range (ꢂ)
Limiting indices
0.35 ꢃ 0.31 ꢃ 0.28
0.31 ꢃ 0.27 ꢃ 0.21
1.79–28.41
1.67–25.02
ꢁ16 ꢄ h ꢄ 10;
ꢁ14 ꢄ k ꢄ 13; ꢁ22 ꢄ l ꢄ 22
14,463/5653 [R(int) ¼ 0.0549]
99.7
Semi-empirical
from equivalents
0.740 and 0.693
Full-matrix least-squares on F2
5653/6/289
ꢁ33 ꢄ h ꢄ 31;
ꢁ7 ꢄ k ꢄ 7; ꢁ19 ꢄ l ꢄ 28
10,285/3327 [R(int) ¼ 0.0204]
99.3
Semi-empirical
from equivalents
0.859 and 0.800
Full-matrix least-squares on F2
3327/0/231
Reflections collected/unique
Completeness to ꢆ ¼ 25.00 (%)
Absorption correction
Max. and min. transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I 4 2ꢆ(I)]
R indices (all data)
0.970
1.067
R1 ¼ 0.0414, wR2 ¼ 0.0638
R1 ¼ 0.0895, wR2 ¼ 0.0755
0.405 and ꢁ0.563
R1 ¼ 0.0235, wR2 ¼ 0.0569
R1 ¼ 0.0261, wR2 ¼ 0.0584
0.472 and ꢁ0.178
Largest difference
peak and hole (e A
ꢁ3
˚
)
0.08 mol), and 60 mL benzene were added. The mixture was stirred for 6 h at 50ꢂC and
transferred into a beaker. After cooling to room temperature it was hydrolyzed with
aqueous HCl (20%) to obtain a white solid which was collected by filtration. The solid
was then dissolved in 20% aqueous NaOH and the excess of solvent was removed by
hydrodistillation. The distillate obtained was acidified by 20% HCl. The solid was
precipitated, washed with water, and recrystallized from ethanol before a pure white
powder was obtained. The yield was 63%; m.p. 122–124ꢂC; IR (KBr, cmꢁ1): ꢁ(Oꢀ ꢀ ꢀH)
1
3400–2500; ꢁasym(COO) 1684; vsym(COO) 1399. H NMR (CDCl3) ꢂ ¼ 2.3 (s, 4H, –
CH2–CO), 7.01–8.23 (m, 5H, Ar–H), 11.63 (s, 1H, –COOH).
2.2.2. Synthesis of (4-(4-biphenyl)-4-oxobutyric acid) (L2H). L2H was prepared by the
same procedure as L1H in which mixture of succinic anhydride (4.003 g, 0.04 mol),
anhydrous aluminum chloride (10.67 g, 0.08 mol), biphenyl (6.17 g, 0.04 mol), and
carbon disulfide (CS2) 60 mL used as solvent gave a pure white powder whose yield was
63%; m.p. 122–124ꢂC; IR (KBr, cmꢁ1): ꢁ(Oꢀ ꢀ ꢀH) 3400–2500; ꢁasym(COO) 1680;
1
vsym(COO) 1441. H NMR (CDCl3) ꢂ ¼ 2.19 (s, 4H, –CH2–CO), 7.20–7.72 (m, 9H,
Ar–H), 11.60 (s, 1H, –COOH).

Di- and tri-organotin carboxylates
3863
2.2.3. Synthesis of [(C6H5)3Sn(L1)2] (1). Triphenyltin hydroxide (0.37 g, 1 mmol) was
added to 50 mL of benzene in which L1H (0.53 g, 1 mmol) was dissolved. After refluxing
for 6 h, the binary azeotrope water/benzene was distilled off with a Dean-Stark funnel.
The reaction mixture was cooled to room temperature and evaporated under vacuum.
Then, recrystallizing the precipitated part twice with ethanol, 1 was obtained with yield
of 70%; m.p. 130–132ꢂC. Anal. Calcd for C28H24O3Sn (%): C, 63.63; H, 4.55; Sn, 22.52.
Found (%): C, 63.79; H, 4.59; Sn, 22.52. IR (KBr, cmꢁ1): ꢁ(C¼O), 1684; vsym(COO)
1403, ꢁasym(COO) 1525; ꢁ(Sn–O) 450 cmꢁ1; ꢁ(Sn–C) 693. 1H NMR (CDCl3, ppm)
ꢂ ¼ 2.85 (t, 2H, CH2–COOSn); 2.87 (t, 2H, CH2–COC6H5); 7.20–7.97 (m, 20H, Ar–H).
2.2.4. Synthesis of [(C6H11)2Sn(L2)] (2). Similar to the procedure for 1, dicyclohex-
yltin oxide (0.301 g, 1 mmol) was added to L2H (0.25 g, 1 mmol) and 2 was obtained
with yield of 66%; m.p. 180–182ꢂC. Anal. Calcd for C44H48O6Sn (%): C, 66.65; H, 6.06;
Sn, 14.98. Found (%): C, 66.76; H, 6.11; Sn, 15.00. IR (KBr, cmꢁ1): ꢁ(C¼O), 1684;
vsym(COO) 1444, ꢁasym(COO) 1601; ꢁ(Sn–O) 492 cmꢁ1; ꢁ(Sn–C) 525. 1H NMR (CDCl3,
ppm) ꢂ ¼ 1.94–1.33 (m, 22H, cyclohexyl–H, SnC6H11); ꢂ ¼ 2.87–2.79 (t, 2H,
CH2–COOSn); 2.89–2.76 (t, 2H, CH2–COC12H9); 7.20–7.70 (m, 18H, Ar–H).
3. Results and discussion
3.1. Syntheses
Proposed schematic diagrams of syntheses of 1 and 2 are shown in scheme 1.
Scheme 1. Syntheses of 1 and 2.

3864
A.M. Sakho et al.
3.2. IR spectroscopic studies
In the IR spectra of L1H and L2H, the O–H stretching vibration was at 3450 and
2800 cmꢁ1. After interactions between carboxyl group and tin, the O–H absorption
disappeared, and ꢁas(COO) and ꢁsym(COO) showed bathochromic shift [16]. The
difference of Dꢁ(ꢁas(COO)–ꢁsym(COO)) is used to determine the coordination mode of
carboxylate tin complexes; if Dꢁ is below 200 cmꢁ1, the carboxyl group is bidentate and
if Dꢁ is more than 200 cmꢁ1, the carboxyl is unidentate [17, 18]. The difference of Dꢁ for
1 and 2 are 285 and 239 cmꢁ1, respectively. The carboxyl groups in 1 and 2 are
unidentate [19, 20].
Absorptions for 1 at 1684, 693, and 450 cmꢁ1 can be assigned to ꢁ(acyl C¼O),
ꢁ(Sn–C), and (Sn–O), respectively. In 2, 525 and 492 cmꢁ1 are assigned to ꢁ(Sn–C) and
(Sn–O) stretching modes.
3.3. 1H NMR spectra
1
In the H NMR spectra of 1 and 2, ꢂCOO–H disappeared, proving that the carboxyl
group participates in coordination at tin. In 1, absorption of two types of protons in
ethyl are 2.85 and 2.87 ppm, while in 2, the chemical shifts of methylene proton in
cyclohexyl group are 1.94–1.33 and 7.20–7.70 ppm for protons in aryl groups. The
hydrogen protons of CO–CH2–CH2–COOSn in 2 are at 2.87–2.79 and 2.89–2.76 ppm.
3.4. Crystal structures of 1 and 2
The crystal structures, 1-D polymeric chain, and the fragment unit of 1 and 2 are shown
in figures 1–4; selected bond lengths and angles are given in table 2.
Figure 1. The molecular structure of 1.

Di- and tri-organotin carboxylates
3865
Figure 2. Perspective view of polymeric chain formed by intermolecular O ! Sn interactions. Hydrogen
atoms are omitted for clarity. Thermal ellipsoids are drawn at 30% probability level. Sn1ꢀ ꢀ ꢀSn1A or
˚
Sn1ꢀ ꢀ ꢀSn1B ¼ 5.835 A (the non-bonded distances). Symmetry codes: (A) 5/2ꢁ x, yꢁ1/2, 1/2ꢁz; (B) x, ꢁ1ꢁy, z.
Figure 3. The molecular structure of 2. Symmetry codes: (A) ꢁ1ꢁ x, y, 1/2ꢁz.
3.4.1. Structure of 1. In 1, tin is five-coordinate and a distorted trans-O2SnC3 trigonal-
bipyramidal structure by coordinating an addition oxygen O(2), which can be regarded as
a ligand from carboxylate anions C1–O2#2. The equatorial plane is defined by the three
R groups, while axial positions are occupied by O1 and O2. The Sn–C bonds are
˚
2.123(3)–2.128(3) A. The carboxylate anions O1–C1 and C1–O2#2 linked to Sn1 give
˚
˚
non-equal Sn–O bond distances of [Sn1–O1 ¼ 2.261(2) A and Sn1–O2 ¼ 2.244(2) A],
respectively. Thus, O2B forms a closer contact with Sn1 than O1, which opens up an
obtuse angle [O2#2–C1–O1 to 123.5(3)ꢂ] from the ideal of 90ꢂ. The axial angle O2–Sn1–
O1 ¼ 174.23(8)ꢂ is close to linear. In the polymeric chain formed, O2 of carboxylate
functions as a bridge, connecting tin centers in a series of intermolecular O ! Sn

3866
A.M. Sakho et al.
Figure 4. View of the tetrahedral tin in 2, showing Sn1ꢀ ꢀ ꢀO interactions. Symmetry codes: (A) ꢁ1ꢁ x, y,
1/2ꢁz.
ꢂ
˚
Table 2. Selected bond lengths (A) and angles ( ) of 1 and 2.
1
Sn1–C21
Sn1–C31
Sn1–C41
Sn1–O2
Sn1–O1
C21–Sn1–C31
C21–Sn1–C41
C31–Sn1–C41
C21–Sn1–O2
C31–Sn1–O2
C21–Sn1–O1
C31–Sn1–O1
2.123(3)
2.126(3)
2.128(3)
2.244(2)
2.261(2)
122.14(13)
120.35(14)
117.49(13)
90.57(11)
92.02(12)
91.81(11)
91.16(12)
O1–C1
1.266(4)
1.254(4)
1.204(5)
1.254(4)
1.508(5)
88.15(11)
174.23(8)
131.9(2)
137.9(2)
123.5(3)
118.9(3)
115.7(3)
O2–C1#1
O3–C4
C1–O2#2
C1–C2
C41–Sn1–O1
O2–Sn1–O1
C1–O1–Sn1
C1#1–O2–Sn1
O2#2–C1–O1
O1–C1–C2
C1–C2–C3
2
Sn1–O1#1
Sn1–O1
2.1063(13)
2.1063(13)
2.1412(19)
2.1412(19)
1.300(2)
O2–C1
O3–C4
C1–O1–Sn1
O2–C1–O1
O2–C1–C2
O1–C1–C2
1.233(2)
1.217(2)
103.29(12)
120.82(18)
122.69(18)
116.48(18)
Sn1–C21#1
Sn1–C21
O1–C1
O1#1–Sn1–O1
O1#1–Sn1–C21#1
O1–Sn1–C21#1
O1#1–Sn1–C21
O1–Sn1–C21
C2#1–Sn1–C21
81.98(7)
108.43(6)
99.89(6)
99.89(6)
108.43(6)
142.29(11)
Symmetry transformations used to generate equivalent atoms: for 1: #1 ꢁx þ 5/2, y þ 1/2, ꢁzꢁ1/2; #2 ꢁx þ 5/2,
yꢁ1/2, ꢁzꢁ1/2, for 2: #1ꢁxꢁ1, y, ꢁz þ 1/2.

Di- and tri-organotin carboxylates
3867
interactions (scheme 1), leading to 1-D polymeric chains (figure 2) containing equal non-
˚
bonded distances of [Sn1ꢀ ꢀ ꢀSn1A and Sn1ꢀ ꢀ ꢀSn1B ¼ (5.835 A)]. Two adjacent tins are
separated by three atoms. Distance reported of two adjacent tins is from 0.519 ꢅ
0.021 nm to 0.7280 nm, which indicates non-covalent character in the solid state.
Substituents on Sn are not influential in coordination with carboxylate [21, 22].
A structure (Bu3SnO2CCH ¼ CHC6F3) has been reported [23] in which similar polymer is
found, with a repeat chain connected by O ! Sn and separated by O–C–O distance
˚
of 5.185 A.
3.4.2. Structure of 2. The molecular structure of 2 is centrosymmetric; tin is four-
coordinate with a distorted tetrahedral geometry (figure 3). This coordination is
completed by two monodentate carboxylates via O1 and O1A. Tetrahedral geometry is
defined by Sn1, C21, and C21A of cyclohexyls and O1 and O1A. O1, Sn1, and O1A and
C21, Sn1, and C21A are isosceles triangles forming an angular sector with Sn1 as
˚
˚
vertex. Sn1–C21 and Sn1–C21A are 2.1412(19) A, Sn1–O1A and Sn1–O1 ¼ 2.1063 A
˚
˚
and the angles are C21–Sn1–C21A ¼ 142.29 A and O1A–Sn1–O1 ¼ 81.98 A. Important
˚
extension angle at 142.29 A may be due to bulky butyl groups attached to Sn. The
Sn1ꢀ ꢀ ꢀO interactions in 2 are shown in figure 4. Rotation from planarity for this
structure can be visualized. O2A, C1A, C2A, O1A, and Sn1 are coplanar; the bond
˚
lengths of Sn1ꢀ ꢀ ꢀO2 and Sn1ꢀ ꢀ ꢀO2A ¼ 2.615 A are less than the sum of the van der
˚
Waals radii (3.58 A) [24].
4. Conclusion
We have synthesized and characterized two organotin carboxylates based on the
esterification of 4-oxo-4-phenyl butanoic acid and 4-(4-biphenyl)-4-oxobutyric acid
with the corresponding triorganotin hydroxide and oxide in 1 : 1 molar ratio. The two
complexes have monodentate carboxylates and 1 is a polymeric chain in which two
˚
adjacent tins are separated by three atoms. Snꢀ ꢀ ꢀSn distance is 5.835 A. In 2, Sn is at the
vertex of two isosceles triangles, with two monodentate carboxylates. Further studies on
the biological activities of 1 and 2 are recommended.
Supplementary material
CCDC nos 791273 and 799845 contain the supplementary crystallographic data for 1
and 2. The data can be obtained free of charge from the Cambridge Crystallographic
Data Center via www.ccdc.cam.ac.uk/data_request.cif
Acknowledgments
We acknowledge the Postdoctoral Science Foundation, P.R. China (No. 2005038561)
and the Department of Chemistry, Gamal Abdel Nasser University, Conakry 1147,

3868
A.M. Sakho et al.
Republic of Guinea. We thank the Laboratory of organotin compounds of Northeast
Normal University, Jilin, Changchun 130024, P.R. China, and Professor DongSheng
Zhu for his valuable remarks.
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