Synthesis, crystal structures and spectral characterization of diorganotin compounds with phenylglyoxylic acid isonicotinyl hydrazone

Article abstract of DOI:10.1016/j.molstruc.2010.11.005

The synthesis and characterization of three organotin(IV) compounds with phenylglyoxylic acid isonicotinyl hydrazone (L) are reported. These compounds with the Schiff base ligand of the type - [R₂SnL_xY _y]_z (x =

Full text of DOI:10.1016/j.molstruc.2010.11.005

Journal of Molecular Structure 985 (2011) 261–269
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Synthesis, crystal structures and spectral characterization of diorganotin
compounds with phenylglyoxylic acid isonicotinyl hydrazone
⇑
Handong Yin , Jing Li, Min Hong, Jichun Cui, Lei Dong, Qijun Zhang
Department of Chemistry, Liaocheng University, Liaocheng 252059, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 11 October 2010
Received in revised form 5 November 2010
Accepted 5 November 2010
Available online 18 November 2010
The synthesis and characterization of three organotin(IV) compounds with phenylglyoxylic acid isonicot-
inyl hydrazone (L) are reported. These compounds with the Schiff base ligand of the type – [R2SnLxYy]z
(x = y = 1, z = 2: R1 = CH3, Y1 = EtOH for compound 1 or R2 = C6H5, Y2 = H2O for compound 2; and x = 2,
y = 0, z = 1, R = n-C4H9 for compound 3) are characterized by IR, 1H, 13C NMR and elemental analysis.
The crystal structures of the Schiff base ligand and the corresponding compounds have been determined
by X-ray diffraction. In compounds 1 and 2, the tin atom is seven-coordinate in a distorted pentagonal
bipyramid geometry chelating by the Schiff base ligand in an enolic tridentate fashion, forming a
Sn2O2 ring, only with different coordinated solvent, water for 2 and ethanol for 1. However, in compound
3, there exists two different coordinate modes for the same ligand, one type of the usual enolic tridentate
and the other type of unique carboxylate monodentate coordination without the participation of the
amide group, this results in the central tin atom presenting six-coordinate in a distorted octahedron
geometry. Fascinatingly, the supramolecular infrastructures were observed in the Schiff base ligand
and three compounds, which exist either as two-dimensional sheets or as three-dimensional networks
assembled from the organometallic subunits through intermolecular OAHÁ Á ÁX or CAHÁ Á ÁX (X@O or N)
hydrogen bonds.
Keywords:
Organotin(IV)
Schiff base
IR
NMR
X-ray diffraction
Ó 2010 Elsevier B.V. All rights reserved.
1. Introduction
tetramers, oligomeric ladders, and hexameric drums, have been
discovered [8–13].
Since some organotin(IV) compounds were synthesized, they
have attracted more and more attention in their characteristics,
such as pharmic value, anti-tumor activity, and biological activity.
In general, the biochemical activity of organotin compounds is
influenced greatly by the structure of the molecule and the coordi-
nation number of the tin atom [1–3]. They are widely used in
microelectronics, nonliner optics, catalysis, host–guest chemistry.
For some time, diorganotin compounds are being investigated for
their anti-tumor activity [4,5]. The diorganotin (IV) anti-tumor
compounds are of tetracoordinated (R2SnX2), pentacoordinated
(R2SnY, where Y is a tridentate ligand), and hexacoordinated
(R2SnX2L2, R = ethyl, n-butyl or phenyl group) geometries [6]. Non-
covalent weak molecular forces capable of connecting these metal-
lic subunits into looser and more intriguing supramolecular
infrastructures (such as hydrogen bonds, Van der Waals forces,
Organotin(IV) compounds with Schiff bases have received
increasing attention owing to their anti-tumor activities and po-
tential applications in biotechnology [14–20]. In addition, Schiff
base organotin(IV) compounds are of interest for structural rea-
sons. The coordination chemistry of some tridentate ONO- and
ONS-donor Schiff bases has been described [21,22], and in this pa-
per we report the synthesis and characterization of three new
organotin(IV) compounds with Schiff base ligand – phenylglyoxylic
acid isonicotinyl hydrazone (L). Their chemical formulas are
[(CH3)2Sn(C14H9N3O3)(C2H5OH)]2 (1), [(C6H5)2Sn(C14H9N3O3)(-
H2O)]2 (2), [(C4H9)2Sn(C14H10N3O3)2] (3). The compounds have
been characterized by elemental analysis, IR, 1H and 13C NMR spec-
troscopy. Interestingly, X-ray diffraction analyses demonstrate that
different coordination modes for the ligand have been observed in
these three compounds although the same reagents and experi-
mental conditions being adopted, which may be due to the differ-
ent reaction molar ratio of ligand and alkyltin salt compared with
those of compounds 1 and 2. Fascinatingly, the supramolecular
infrastructures were observed in the Schiff base ligand and three
compounds, which exist either as two-dimensional sheets or as
three-dimensional networks assembled from the organometallic
subunits through intermolecular OAHÁ Á ÁX or CAHÁ Á ÁX (X = O or
N) hydrogen bonds.
nonbonded contacts, and
p–p interactions) [7]. The latter aspect
has been actively investigated by a large number of researchers,
and a multitude of structural types, including monomers, dimers,
⇑
Corresponding author. Tel./fax: +86 6358239121.
E-mail address: handongyin@163.com (H. Yin).
0022-2860/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2010.11.005

262
H. Yin et al. / Journal of Molecular Structure 985 (2011) 261–269
anol and toluene (v/v = 1/3) (30 ml) with sodium ethoxide
2. Experimental
(0.0274 g, 0.4 mmol), the mixture was stirred for half an hour,
(C6H5)2SnCl2 (0.1375 g, 0.4 mmol) was then added, and the reac-
tion mixture was refluxed for 10 h and then filtered and evapo-
rated to dryness under vacuum to form a yellow solid, and then
recrystallized from dichloromethane–hexane to give yellow single
crystal. Yield: 75%. Anal. Calc. for C52H42N6O8Sn2: C 55.95, H 3.79, N
7.53%. Found: C 56.12, H 3.68, N 7.45%. 1H NMR (CDCl3, d ppm):
6.85–6.97 (m, 20H, AC6H5), 7.30–7.62 (m, 10H, AC6H5), 8.01–
8.80 (m, 8H, AC5H4N). 13C NMR (CDCl3, 400 MHz): 173.31 (COO),
163.09, 140.94 (C@NAN@C), 150.20, 150.20, 140.11, 122.09,
122.09 (AC5H4N), 132.23, 131.18, 129.39, 129.39, 127.77, 127.77
(AC6H5), 137.52, 137.52, 130.25, 128.84, 128.84, 128.84 (SnAC6H5)
ppm. IR (KBr, cmÀ1): 3058 (s, ArAH), 1625, 1380 (m, COO), 3441 (s,
NH), 1660 (s, C@N), 1604 (s, C@NAN@C), 565 (m, SnAO), 532 (w,
SnAC), 472 (w, SnAN).
2.1. Materials and measurements
Dimethyltin chloride, di-n-butyltin chloride, diphenyltin chlo-
ride, isonicotinyl hydrazide, phenylglyoxylic acid were commer-
cially available and used without further purification. All the
solvents used in the reaction were of analytical grade and were
dried before use.
Infrared-spectra were recorded on a Nicolet-460 spectrophoto-
metre using KBr discs and sodium chloride optics, 1H and 13C NMR
spectra were recorded on a Varian Mercury Plus 400 spectrometer
operating at 400 MHz. The TMS was used as internal standard. The
chemical shifts were given in ppm in CDCl3 solvent. Elemental
analyses were performed with a PE-2400 II elemental analyser.
2.2. Synthesis of Schiff base ligand – phenylglyoxylic acid isonicotinyl
hydrazone
2.3.3. Preparation of compound [(n-C4H9)2Sn(C14H10N3O3)2] (3)
Compound 3 was prepared using the procedure as following de-
scribed. The ligand (0.1077 g, 0.4 mmol) and sodium ethoxide
(0.0274 g, 0.4 mmol) were added in the mixture of ethanol and
benzene (v/v = 2/1, 30 ml) and heated in standard Schlenk tech-
nique, and the mixture was stirred for 20 min. (n-C4H9)2SnCl2
(0.0608 g, 0.2 mmol) was then added to the mixture, and the reac-
tion was refluxed for 8 h. The solution was filtered and the solvent
of the filtrate was gradually removed by evaporation under vac-
uum until solid product was obtained. The solid was then recrys-
tallized from dichloromethane to give yellow single crystal.
Yield: 68%. Anal. Calc. for C36H38N6O6Sn: C 56.20, H 4.98, N
10.92%. Found: C 56.32, H 4.92, N 10.85%. 1H NMR (CDCl3, d
ppm): 0.91 (t, 6H, ACH3), 1.37–1.42 (m, 8H, ACH2CH2A), 1.68–
1.82 (m, 4H, SnACH2A), 7.26–7.59 (m, 10H, AC6H5), 7.99–8.80
(m, 8H, AC5H4N), 8.60 (s, 1H, ANH), 11.65 (s, 1H, ANHN@ @). 13C
NMR (CDCl3, 400 MHz): 175.31 (COO), 163.01, 152.94
(C@NAN@C), 149.43, 149.43, 140.94, 122.39, 122.39 (AC5H4N),
132.30, 130.10, 128.43, 128.43, 127.80, 127.80 (AC6H5), 26.75,
26.46, 21.93, 13.46 (n-C4H9ASn) ppm. IR (KBr, cmÀ1): 3065 (s,
ArAH), 1637, 1384 (m, COO), 3436 (s, NH), 1637 (s, C@N), 1600
(s, C@NAN@C), 570 (m, SnAO), 540 (w, SnAC), 470 (w, SnAN).
In typical procedure, isonicotinyl hydrazide (1.37 g, 10 mmol)
and phenylglyoxylic acid (1.80 g, 10 mmol) was added in CH3OH
(60 ml). The mixture was mechanically stirred and reflux for 4 h.
After evaporation of the solvent, the crude product was collected,
it was washed first with ethanol and then with dichloromethane–
ethanol. For some time, yellow single crystal was formed. Yield:
85%, m.p. 483–485 K. Anal. Calc. for C14H11N3O3: C 62.45, H 4.12,
N 15.61%. Found: C 62.63, H 4.06, N 15.55%. (see: Scheme 1).
2.3. Synthesis of the organotin(IV) compounds
2.3.1. Preparation of [(CH3)2Sn(C14H9N3O3)(C2H5OH)]2 (1)
The reaction was carried out under nitrogen atmosphere with
the use of standard Schlenk technique. The phenylglyoxylic acid
isonicotinyl hydrazone (0.1077 g, 0.4 mmol) was added to a solu-
tion of absolute ethanol (30 ml) with sodium ethoxide (0.0274 g,
0.4 mmol), the mixture was stirred for half an hour, (CH3)2SnCl2
(0.0677 g, 0.4 mmol) was added, stirring for 6 h under refluxing.
After cooling down to room temperature, filtrated it and evapora-
tion to dryness, the solid was then recrystallized from dichloro-
methane–ethanol and yellow single crystal was formed by slow
evaporation at room temperature. Yield: 72%. Anal. Calc. for
Table 1
Crystal data and structure refinement parameters for the ligand.
C
36H42N6O8Sn2: C 46.79, H 4.59, N 9.09%. Found: C 46.62, H 4.54,
Empirical formula
C14H11N3O3
N 9.03%. 1H NMR (CDCl3, d ppm): 0.97 (t, 12H, ACH3), 1.42 (t, 6H,
ACH2ACH3), 3.67 (m, 4H, AOACH2A), 8.53 (s, 2H, AOH), 7.25–
7.60 (m, 10H, AC6H5), 8.00–8.83 (m, 8H, AC5H4N). 13C NMR (CDCl3,
400 MHz): 173.20 (COO), 163.08, 140.60 (C@NAN@C), 47.34
(AOCH2), 21.93 (ACH2ACH3), 149.66, 149.66, 140.60, 125.07,
125.07 (AC5H4N), 132.27, 131.18, 130.13, 130.13, 128.23, 128.23
(AC6H5), 18.40 (SnAMe) ppm. IR (KBr, cmÀ1): 3050 (s, ArAH),
1635, 1397 (m, COO), 3434 (s, NH), 1635 (s, C@N), 1617 (s,
C@NAN@C), 560 (m, SnAO), 533 (w, SnAC), 459 (w, SnAN).
Formula weight
Wavelength (Å)
Crystal system
Space group
Unit cell dimensions
a (Å)
269.26
0.71073
Monoclinic
P2(1)/c
7.3422(7)
17.5751(2)
10.4566(1)
110
1267.5(2)
4
1.411
0.102
b (Å)
c (Å)
b (°)
Volume (Å3)
Z
Calculated density (mg/m3)
Absorption coefficient (mmÀ1
F(0 0 0)
2.3.2. Preparation of compound [(C6H5)2Sn(C14H9N3O3)(H2O)]2 (2)
Compound 2 was prepared by the similar method as compound
1. The ligand (0.1077 g, 0.4 mmol) was added to the mixture of eth-
)
560
Crystal size (mm)
Theta range for data collection (°)
Limiting indices
Reflections collected/unique
Completeness to theta = 25.01
Absorption correction
Max. and min. transmission
Refinement method
0.40 Â 0.24 Â 0.16
2.32–25.01
À6 6 h 6 8, À19 6 k 6 20, À12 6 l 6 6
6320/2241 [R(int) = 0.1184]
99.8%
Semi-empirical from equivalents
0.9838 and 0.9602
Full-matrix least-squares on F2
2241/0/181
Data/restraints/parameters
Goodness-of-fit on F2
1.017
Final R indices [I > 2
r
(I)]
R1 = 0.0592, wR2 = 0.1149
R1 = 0.1030, wR2 = 0.1290
0.342 and À0.243
R indices (all data)
Largest diff. peak and hole (e ÅÀ3
)
Scheme 1. Schiff base.

H. Yin et al. / Journal of Molecular Structure 985 (2011) 261–269
263
2.4. X-ray crystallography
SMART CCD 1000 diffractometer. A criterion of observability was
used for the solution and refinement. The structure was solved
by direct methods (program SHELXL-97 [23]) and refined by a
full-matrix least-squares procedure based on F2 data using the
Crystallographic data and refinement details are given in Tables
1 and 2. All X-ray diffraction pattern were collected on a Bruker
Table 2
The crystallographic data for compounds 1–3.
Empirical formula
1
2
3
C
36H42N6O8Sn2
C52H42N6O8Sn2
C36H38N6O6Sn
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
924.14
298(2)
0.71073
Monoclinic
C2/c
1116.30
298(2)
0.71073
Monoclinic
P2(1)/n
769.41
298(2)
0.71073
Orthorhombic
Pbca
Unit cell dimensions
a (Å)
b (Å)
c (Å)
14.9911(15)
9.1840(10)
28.419(3)
9.7108(10)
10.3070(11)
24.264(2)
16.6980(17)
20.364(2)
21.920(2)
b (°)
96.6470(10)
3886.4(7)
98.1510(10)
2404.0(4)
90
Volume (Å3)
7453.6(14)
Z
4
2
8
Calculated density (mg/m3)
Absorption coefficient (mmÀ1
F(0 0 0)
1.579
1.342
1856
1.542
1.100
1120
1.371
0.736
3152
)
Crystal size (mm)
Scan range h (°)
Limiting indices
0.22 Â 0.13 Â 0.11
0.42 Â 0.30 Â 0.17
0.42 Â 0.21 Â 0.13
1.44–25.02
2.15–25.02
1.83–25.02
À16 6 h 6 17
À5 6 k 6 10
À33 6 l 6 33
9860/3435 [R(int) = 0.0547]
99.9%
Semi-empirical from equivalents
0.8664 and 0.7567
Full-matrix least-squares on F2
3435/598/258
1.018
À11 6 h 6 10
À11 6 k 6 12
À28 6 l 6 28
12,122/4244 [R(int) = 0.0347]
99.9%
Semi-empirical from equivalents
0.8351 and 0.6551
Full-matrix least-squares on F2
4244/0/307
À19 6 h 6 19
À24 6 k 6 24
À26 6 l 6 16
37,218/6574 [R(int) = 0.0985]
100.0%
Semi-empirical from equivalents
0.9104 and 0.7474
Full-matrix least-squares on F2
6574/1/444
Reflections collected/unique
Completeness to theta = 25.02
Absorption correction
Max. and min. transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
1.070
1.152
Final R indices [I > 2
R indices (all data)
r(I)]
R1 = 0.0392
wR2 = 0.0801
R1 = 0.0602
R1 = 0.0332
wR2 = 0.0707
R1 = 0.0518
R1 = 0.0595
wR2 = 0.1317
R1 = 0.1624
wR2 = 0.0864
0.794 and À0.679
wR2 = 0.0823
0.743 and À0.375
wR2 = 0.2116
1.153and À0.671
Largest diff. peak and hole (e ÅÀ3
)
Scheme 2. Synthesis of organotin(IV) compounds.

264
H. Yin et al. / Journal of Molecular Structure 985 (2011) 261–269
Table 3
Selected bond lengths (Å) and angles (°) of the ligand.
O3AC8
1.284(3)
N3AC7
1.292(3)
C6AO1
C7AC8
C7AN3AN2
O2AC8AC7
1.222(3)
1.522(3)
119.0(2)
120.0(2)
C7AC9
C8AO2
O2AC8AO3
O3AC8AC7
1.489(4)
1.241(3)
124.8(2)
115.1(3)
nate in a distorted pentagonal bipyramid geometry. However,
when the di-n-butyltin chloride and the ligand were added with
the molar ratio of 1:2, a unique mononuclear diorganotin(IV) com-
pound 3 were obtained, and the central tin atom is six-coordinate
in a distorted octahedron geometry.
3.2. IR spectra
The IR spectra of organotin Schiff base compounds provide use-
ful information about the coordination of the functional groups.
The data show the metal–ligand bonds formation through ACO2A,
AOA and AN sites, and the associated SnAOASn, SnAO and SnAN
Fig. 1. The molecular structure of Schiff base.
absorption values are also support this. The Dm[m m
as(COÀ2 )– s(COÀ2 )]
SHELXL-97 [24] program system. All data were collected at
298(2) K using graphite-monochromated Mo K (k = 0.71073 Å)
values (230–282 cmÀ1) for compounds 1–3, indicate that the car-
boxylate groups adopt the monodentate coordination mode [27].
The characteristic absorption at 1630–1665 cmÀ1 can indicate the
presence of C@N group [28]. The characteristic absorption at
1600–1620 cmÀ1 in the spectra of these compounds indicate the
presence of the C@NAN@C group [29], thus indicating the ligand
coordinate to the tin centre in an enolic form, which is in accor-
dance with the X-ray structure analysis and their corresponding
reaction mechanism.
a
radiation. Non-hydrogen atoms were refined with anisotropic dis-
placement parameters; hydrogen atoms were included from geom-
etry of molecules and
Dq maps. During the refinement process
they treated as riding atoms [23–26].
3. Results and discussion
3.1. Synthesis of organotin (IV) compounds
3.3. 1H and 13C NMR spectra (CDCl3)
Compounds 1–3 were obtained by the reactions of phenylgly-
oxylic acid isonicotinyl hydrazone with the alkyltin salt at the
presence of sodium ethoxide in different molar ratios and solvent
(ethanol for 1, the mixture of ethanol and toluene for 2 and the
mixture of ethanol and benzene for 3) under the reflux conditions
(see Scheme 2). The mixture of the dimethyltin chloride or diphe-
nytin chloride, phenylglyoxylic acid isonicotinyl hydrazone and the
sodium ethoxide in the molar ratio of 1:1:1 was found to given the
similar molecule structure – dimer, the tin atom is seven-coordi-
All compounds are given good NMR spectra. In the 1H NMR
spectra of free ligand, the single resonance for the proton of the
ANHN = group is observed at d = 10.8–12.8 ppm, and is absent in
the spectra of the compounds, thus indicating deprotonation of
the ANHN = group and conforming that the ligand coordinate to
the Sn centre in the enolic form. For all compounds, the spectra
show that the chemical shifts of the protons on the aryl group have
been assigned reasonably. The 1H NMR spectra of the dimethyltin
Fig. 2. The two-dimensional sheet of the Schiff base ligand, formed by NAHÁ Á ÁO, CAHÁ Á ÁO and OAHÁ Á ÁN.

H. Yin et al. / Journal of Molecular Structure 985 (2011) 261–269
265
Table 4
Geometry parameters of hydrogen bonding geometries for the ligand and compounds 1–3.
Ligand
DÁ Á ÁA
DAH
HÁ Á ÁA
DÁ Á ÁA
DAHÁ Á ÁA
N2AH6Á Á ÁO2
0.86
0.93
0.93
0.93
0.82
1.91
2.53
2.66
2.62
1.78
2.586(2)
3.149(3)
3.494(4)
3. 239(3)
2.596(3)
134.0
124.2
148.9
124.4
175.2
C1AH1Á Á ÁO2#1
C5AH5Á Á ÁO3#2
C10AH10Á Á ÁO1#3
O3AH8Á Á ÁN1#4
Compound 1
DAHÁ Á ÁA
DAH
0.83(9)
0.93
HÁ Á ÁA
1.82(9)
2.72
DÁ Á ÁA
DAHÁ Á ÁA
161(10)
150.7
O(4)AH(1)Á Á ÁO(2)#1
C(4)AH(4)Á Á ÁN(3)#2
2.625(4)
3.562(6)
Compound 2
DAHÁ Á ÁA
DAH
0.85
0.85
0.86
0.93
HÁ Á ÁA
2.63
1.78
1.84
2.61
DÁ Á ÁA
DAHÁ Á ÁA
118.0
172.8
174.0
147.5
O4AH4AÁ Á ÁO1#1
O4AH4AÁ Á ÁO2#1
O4AH4BÁ Á ÁN3#2
C22AH22Á Á ÁO3#3
3.121(3)
2.620(4)
2.695(4)
3.430(6)
Compound 3
DAHÁ Á ÁA
DAH
0.89
0.86
0.86
0.93
0.93
0.93
0.93
0.93
0.93
HÁ Á ÁA
2.02
2.36
2.04
2.58
2.30
2.50
2.66
2.31
3.10
DÁ Á ÁA
DAHÁ Á ÁA
133.5
130.3
169.8
116.6
162.6
159.9
116.9
172.1
90.7
N5AH5AÁ Á ÁO5
2.710(13)
2.990(12)
2.888(11)
3.107(14)
3.200(15)
3.390(18)
3.192(16)
3.238(15)
3.248(18)
N3AH3Á Á ÁO1#1
N3AH3Á Á ÁO2#1
C14AH14Á Á ÁO1#1
C14AH14Á Á ÁO4#1
C24AH24Á Á ÁO2#2
C27AH27Á Á ÁO2#3
C(10)AH(10)Á Á ÁN(4)#4
C(10)AH(10)Á Á ÁN(6)#5
Symmetry codes: for Schiff base: #1 x + 1, y, z + 1; #2 À x, Ày + 1, Àz; #3 x, Ày + 1/2, z À 1/2; #4 x À 1, y, z À 1; for compound 1: #1 À x,À y + 2, Àz; #2 À x + 1/2, y + 1/2,
Àz + 1/2; for compound 2: #1 À x, Ày + 2, Àz; #2 À x À 1/2, y + 1/2, Àz + 1/2; #3 x + 1, y, z; for compound 3: #1 À x + 1/2, Ày + 1, z + 1/2; #2 À x + 1, y À 1/2, Àz + 1/2;
#3 À x + 1/2, y À 1/2, z; #4 x, Ày + 1/2, z + 1/2; #5 x À 1/2, Ày + 1/2, Àz + 1.
compound show the signal of SnACH3 at 0.97 ppm. In the 13C NMR
spectra of compounds, there contain one or two five-membered
ring, and correspondingly, at 140–165 ppm three peaks were ob-
served for the bonding C atoms. The 13C NMR data are consistent
with carboxylate structures, the single at 173.20–175.31 ppm. In
three compounds, the biggest difference of the 13C NMR come from
the change of the alkyl groups bonding with tin centre.
3.4.2. Crystal structures of compounds 1 and 2
The crystallographic data of compounds 1 and 2 are given in Ta-
ble 2. The molecular structure of the compounds 1 and 2 is shown
in Figs. 3 and 4. Compounds 1 and 2 have the similar bridged di-
meric structure, which also present the identical structure geome-
try of trans-C2SnO4N pentagonal bipyramid with that of compound
1 for the central tin atom, only with different coordinated solvent,
ethanol for 1 and water for 2 and the different alkyl groups, methyl
group for 1 and benzyl group for 2. In other words, the nature the
alkyl group and the coordinated solvent molecule bonding to the
Sn centre does not play an important role on the structure of
bridged dimers. The selected bond lengths and angles are given
in Table 5. In compound 1, the tin atom is surrounded equatorially
3.4. X-ray crystallography
3.4.1. Crystal structure of Schiff base ligand
The molecular structure and the two-dimensional sheet of
Schiff base is shown in Figs. 1 and 2. The crystal data and structure
refinement parameters and selected bond lengths and angles are
shown in Tables 1 and 3. The H-bonds are given in Table 4. All H
atoms were positioned geometrically and treated as riding on their
parent atoms, with CAH distances of 0.93 Å and displacement
parameters assigned as
Uiso(H) = 1.2Ueq(C). The angle of the
C7AN3AN2@C6 is À178.6(2)°, and due to the presence of the lone
pair electron for nitrogen atom, it is the conducive to the coordina-
tion to the metal centre. The bond lengths O3AC8 and C8@O2 are
1.284(3) and 1.241(3) Å, which are greater shorter than CAO
(1.43 Å) and less longer than C@O (1.20 Å). The O3AC8@O2 is con-
sidered conjugated system. From the structure, it is inferred that
the N and O atoms can participate in the coordination.
In the Schiff base, there are one intramolecular hydrogen bond
and four intermolecular hydrogen bonds. The distance of the
N2AH6Á Á ÁO2 is 1.91 Å. The distance of the O3AH8Á Á ÁN1#4
(#4x À 1, y, z À 1) is 1.71 Å. The distance of CAHÁ Á ÁO is 2.53–
2.66 Å. The hydrogen bonds make the Schiff base form two-dimen-
sional laminated structure. Obviously, these H-bonds supply the
additional stability effect for the solid-state structure of the Schiff
base.
Fig. 3. The molecular structure of compound 1.

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H. Yin et al. / Journal of Molecular Structure 985 (2011) 261–269
Fig. 4. Crystal structure of compound 2.
Fig. 5. Two-dimensional sheet structure of compound 1, formed by O4AH1Á Á ÁO2#1 and C4AH4Á Á ÁN3#2.
by four O atoms and one C atom from the ligand, and the axis posi-
tion is occupied by two C atoms from the methyl group. The
Sn1AC15 distance is 2.096(4) Å, the Sn1AC16 distance is
2.101(5) Å. The angle of C15ASn1AC16 is 164.08(18)°, which is
deviated from linear angle 180°. It is a centrosymmetric arrange-
ment leading to a Sn2O2 core connected by the SnAO bond, and
the Sn1AO1#1 bond distance is 2.717(3) Å, is greater than the
sum of the covalent radii of Sn and O (2.56 Å), but is considerably
less than the sum of the Van der Waals radii SnAO (3.68 Å), indi-
cating the weak bonding interaction between Sn1 and O1#1. The
Sn1AN1 distance is 2.274(3) Å, which is greater longer than the
sum of the covalent radii of Sn and N (2.15 Å), but is considerably
less than the sum of the Van der Waals radii (3.75 Å) [30], and
should be considered as bonding interactions. It is worth mention-
ing that the solvent molecule – ethanol involved in the coordina-
tion in a disordered structure. In compound 1, there exists

H. Yin et al. / Journal of Molecular Structure 985 (2011) 261–269
267
Table 5
the Sn1 atom. The angle of the axial C1ASn1AC7 is 173.77(15) Å.
O1 atom of the carboxylate residue also binds the other tin atom,
Selected bond lengths (Å) and angles (°) for compounds 1 and 2.
generating
a Sn2O2 four-membered ring. The distance of
Compound 1
Sn1AO1#1 is 2.561(2) Å, close to the sum of the covalent radii of
Sn and O (2.56 Å), indicating the strong tin–oxygen interaction.
The Sn1AN1 is 2.315(3) Å, which is greater longer than the sum
of the covalent radii of Sn and N 2.15 Å, but is considerably less
than the sum of the Van der Waals radii (3.75 Å) [28], and should
be considered as the bonding interactions. The intermolecular
chains O4AH4AÁ Á ÁO1#1 (#1 À x, Ày + 2, Àz), O4AH4AÁ Á ÁO2#1
(#1 À x, Ày + 2, Àz), C22AH22Á Á ÁO3#3 (#3x + 1, y, z) and
O4AH4BÁ Á ÁN3#2 (#2 À x À 1/2, y + 1/2, Àz + 1/2) hydrogen bonds
to generate three-dimensional network (Fig. 6), which makes the
compound more stable.
Sn1AC15
Sn1AO3
Sn1AO1
Sn1AO1#1
C15ASn1AC16
N1ASn1AO1
O1ASn1AO1#1
2.096(4)
2.196(3)
2.325(3)
Sn1AC16
Sn1AN1
Sn1AO4
2.101(5)
2.274(3)
2.391(3)
2.717(3)
164.08(19)
69.03(10)
66.09(11)
O3ASn1AN1
O3ASn1AO4
O4ASn1AO1#1
69.84(11)
76.94(11)
78.09(10)
Compound 2
Sn1AC7
Sn1AO3
2.130(4)
2.207(2)
2.315(3)
Sn1AC1
Sn1AO4
Sn1AO1
2.139(4)
2.263(3)
2.371(2)
Sn1AN1
Sn1AO1#1
C7ASn1AC1
O3ASn1AN1
N1ASn1AO1
2.561(2)
173.79(15)
69.19(10)
68.10(9)
O3ASn1AO4
O1ASn1AO1#1
O4ASn1AO1#1
75.83(9)
66.48(10)
80.39(8)
3.4.3. Crystal structure of compound 3
The molecular structure of the compound 3 is shown in Fig. 7.
The crystallographic data and selected bond lengths and angles
are given in Tables 2 and 6. There was no interaction between
the Sn1 atom and O1 atom (Sn1AO1#1). The central tin atom is
six-coordinate in a distorted octahedron geometry and the central
tin atom is surrounded equatorial by N1, O1, O3, O4 from the li-
gand and the C29 and C33 from the n-butyl group taking up the ax-
ial positions. The angle of the axial C33ASn1AC29 is 156.6(5)°,
which is deviated from the linear angle of 180°. The bond length
of Sn1AO4 is 2.278(7) Å. The tin atom, the bonded oxygen and
nitrogen atoms are nearly coplanar and deviate only slightly from
regular square geometry, mean deviation from planar is 0.07 Å. The
Sn1AN1 distance, 2.290(9) Å, which is greater than the sum of the
Symmetry code: (#1 for 1) Àx, Ày + 2, Àz; (#1 for 2) #1 À x, Ày + 2, Àz.
intermolecular hydrogen bonds O4AH1ÁÁÁO2#1, C4AH4Á Á ÁN3#2,
which contribute to the formation of the two-dimensional sheet
(Fig. 5).
In compound 2, the central tin is surrounded equatorial by O1,
O1#1, N1, O3 from the ligand and O4 from the solvent molecule –
water. The sum of angles N1ASn1AO1, O3ASn1AN1, O3ASn1AO4,
O4ASn1AO1#1 and O1ASn1AO1#1 subtends at the Sn1 atom in
the pentagonal plane is 360°, so O1, O1 #1, N1, O3 and O4 are in
the same plane. The benzyl group takes up the axial sites around
Fig. 6. (a) One-dimensional chain structure of compound 2, O4AH4AÁ Á ÁO1, O4AH4AÁ Á ÁO2#1, C22AH22Á Á ÁO3#3; (b) Three-dimensional network of compound 2, formed by
O4AH4AÁ Á ÁO1, O4AH4AÁ Á ÁO2, C22AH22Á Á ÁO3 and O4AH4BÁ Á ÁN3.

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H. Yin et al. / Journal of Molecular Structure 985 (2011) 261–269
Fig. 7. Crystal structure of compound 3.
Table 6
NAHÁ Á ÁO hydrogen bonds (Table 4), and a three-dimensional net-
Selected bond lengths (Å) and angles (°) for compound 3.
work (Fig. 8) is created by them. They create network along the
crystallographic [0 1 0] axis.
Sn1AC33
Sn1AO1
Sn1AN1
C33ASn1AC29
O1ASn1AN1
N1ASn1AO3
2.089(13)
2.152(8)
2.290(9)
156.6(5)
71.0(3)
68.0(3)
Sn1AC29
Sn1AO4
Sn1AO3
O1ASn1AO4
O4ASn1AO3
2.124(13)
2.278(7)
2.308(7)
75.3(3)
4. Conclusions
145.8(3)
Three new organotin compounds derived from Schiff base –
phenylglyoxylic acid isonicotinyl hydrazone have been reported
here. Our investigation on the structures and spectra of these com-
pounds indicate that the structures of compound 1 and compound
2 have a distorted pentagonal bipyramid and compound 3 has a
distorted octahedron geometry. In compounds 1 and 2, the central
tin atom is seven coordinated, but in compound 3, the central tin
atom is six coordinated. Besides, the R groups of the R2Sn are found
covalent radii of Sn and N 2.15 Å, but is considerably less than the
sum of the Van der Waals radii (3.75 Å) [28], indicating the strong
bond of SnAN interactions. There are intramolecular NAHÁ Á ÁO
hydrogen bond and intermolecular CAHÁ Á ÁO, CAHÁ Á ÁN and
Fig. 8. Three-dimensional network of compound 3, formed by CAHÁ Á ÁN, CAHÁ Á ÁO and NAHÁ Á ÁO.

H. Yin et al. / Journal of Molecular Structure 985 (2011) 261–269
269
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Crystallographic data for the structural analyses have been
deposited with the Cambridge Crystallographic Data Centre, CCDC
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pounds 1–3, respectively. These data can be obtained free of charge
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Cambridge Crystallographic Data Centre, 12 Union Road, Cam-
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Acknowledgements
We acknowledge the National Natural Foundation of China
(20771053), the National Basic Research Program (No.
2010CB234601), the Natural Science Foundation of Shandong
Province (Y2008B48) for financial support. And this work was sup-
ported by Shandong ‘‘Tai-Shan Scholar Research Fund’’.
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