Diorganotin(IV) derivatives containing the 3,5-dimethyl-4-(4′- pyridyl)pyrazole ligand

Article abstract of DOI:10.1016/j.poly.2004.11.016

3,5-Dimethyl-4-(4′-pyridyl)pyrazole, prepared by the reaction of 3-(4-pyridyl)pentane-2,4-dione with hydrazine hydrate, reacts with R ₂SnCl₂ (R = Ph, Et and n-Bu) in a 1:1 ratio to yield 2:1 (ligand:tin) adducts. In the crystal structure of the Ph₂SnCl ₂ adduct, two 3,5-dimethyl-4-(4′-pyridyl)pyrazole ligands coordinate to the tin atom through the pyridyl nitrogen atom instead of the pyrazolyl nitrogen atom, and the molecules are connected into a linear chain through intermolecular N-H?N hydrogen bonds. The reaction of 3,5-dimethyl-4-(4′-pyridyl)pyrazole with dibromomethane under phase transfer catalytic conditions affords bis[3,5-dimethyl-4-(4′-pyridyl) pyrazol-1-yl]methane. Treatment of this potential polydentate ligand with R ₂SnCl₂ yields 1:1 adducts, in which bis[3,5-dimethyl-4- (4′-pyridyl)pyrazol-1-yl]methane coordinates to the tin atom through the pyridyl nitrogen atom to form six-coordinate diorganotin linkage coordination polymers, leading to a bridging instead of a general chelating metal coordination. In all new complexes, the pyridyl nitrogen atom exhibits stronger donating ability than the pyrazolyl nitrogen to the tin atom.

Full text of DOI:10.1016/j.poly.2004.11.016

Polyhedron 24 (2005) 209–214
www.elsevier.com/locate/poly
Diorganotin(IV) derivatives containing the
3,5-dimethyl-4-(40-pyridyl)pyrazole ligand
a
Qian Cui , Xiu-Ying Cao , Liang-Fu Tang
b
a,
*
a
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, PR China
b
Tianjin Institute of Scientific and Technical Information, Tianjin 300074, PR China
Received 28 September 2004; accepted 2 November 2004
Available online 19 December 2004
Abstract
3,5-Dimethyl-4-(40-pyridyl)pyrazole, prepared by the reaction of 3-(4-pyridyl)pentane-2,4-dione with hydrazine hydrate, reacts
with R2SnCl2 (R = Ph, Et and n-Bu) in a 1:1 ratio to yield 2:1 (ligand:tin) adducts. In the crystal structure of the Ph2SnCl2 adduct,
two 3,5-dimethyl-4-(40-pyridyl)pyrazole ligands coordinate to the tin atom through the pyridyl nitrogen atom instead of the pyraz-
olyl nitrogen atom, and the molecules are connected into a linear chain through intermolecular N–Hꢀ ꢀ ꢀN hydrogen bonds. The
reaction of 3,5-dimethyl-4-(40-pyridyl)pyrazole with dibromomethane under phase transfer catalytic conditions affords bis[3,5-
dimethyl-4-(40-pyridyl)pyrazol-1-yl]methane. Treatment of this potential polydentate ligand with R2SnCl2 yields 1:1 adducts, in
which bis[3,5-dimethyl-4-(40-pyridyl)pyrazol-1-yl]methane coordinates to the tin atom through the pyridyl nitrogen atom to form
six-coordinate diorganotin linkage coordination polymers, leading to a bridging instead of a general chelating metal coordination.
In all new complexes, the pyridyl nitrogen atom exhibits stronger donating ability than the pyrazolyl nitrogen to the tin atom.
ꢀ 2004 Elsevier Ltd. All rights reserved.
Keywords: Bis(pyrazol-1-yl)methane; Organotin(IV); Pyridine; X-ray structure
1. Introduction
coordination geometry of the tin atom. Recently, we
have also successfully prepared a variety of five and
six-coordinate organotin(IV) complexes with symmetric
or asymmetric bis(pyrazol-1-yl)methane [12,13], and
bidentate organotin Lewis acid derivatives of bis(pyra-
zol-1-yl)methane [14,15], as well as novel five and six-
coordinate diorganotin(IV) linkage coordination
polymers with bis(1,2,4-triazol-1-yl)methane [16].
Poly(pyrazol-1-yl)alkanes containing heteroatoms such
as phosphine or sulfur in the pyrazolyl rings display var-
iable coordination modes toward different metals
[17,18], which encourages us to investigate the effects
of more extensive donor sets on the coordination modes
of poly(pyrazol-1-yl)alkanes. Herein, we report the syn-
thesis and structural characterization of diorganotin(IV)
derivatives containing 3,5-dimethyl-4-(40-pyridyl)pyraz-
ole. Treatment of diorganotin(IV) chloride with this li-
gand yields 1:2 adducts, while employment of its
For a long time diorganotin complexes containing
nitrogen donor ligands have attracted considerable
attention due to their potential biological applications
[1,2]. Many complexes of the type R2SnX2(N–N) have
been synthesized and tested for their antitumor activities
[3–5]. Poly(pyrazol-1-yl)alkanes, especially bis(pyrazol-
1-yl)methanes, have also been found to act as good do-
nors to organotin compounds [6–11]. The interactions
between poly(pyrazol-1-yl)alkanes and tin(IV) or
organotin(IV) acceptors indicate that the donating abil-
ity of the ligands can be easily controlled by varying the
substituents of the pyrazolyl ring, leading to a variable
*
Corresponding author. Tel.: +86 22 234 99114; fax: +86 22 235
02458.
E-mail address: lftang@nankai.edu.cn (L.-F. Tang).
0277-5387/$ - see front matter ꢀ 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2004.11.016

210
Q. Cui et al. / Polyhedron 24 (2005) 209–214
derivative, bis(3,5-dimethyl-4-(40-pyridyl)pyrazol-1-yl)
methane, gives a 1D linkage coordination polymer.
7.50 (d, 4H, b-PyH), 8.06, 7.41 (m, m, 4H, 6H, C6H5),
2.36 (s, 12H, CH3). IR: mNH = 3294.0 (m); mpyridyl ring
=
1612.4 (s) cmꢁ1. Anal. Calc. for C32H32Cl2N6Sn: C,
55.68; H, 4.67; N, 12.18. Found: C, 55.75; H, 4.84; N,
12.49%.
2. Experimental
Solvents were dried by standard methods and dis-
tilled prior to use. NMR spectra (1H, 13C and 119Sn)
were recorded on a Bruker AV300 spectrometer, and
the chemical shifts were reported in ppm with respect
to reference standards (internal SiMe4 for 1H NMR
and 13C NMR spectra, external SnMe4 for 119Sn
NMR). IR spectral data were obtained from a Bruker
Equinox55 spectrometer in KBr pellets. Elemental anal-
yses were carried out on a Perkin–Elmer 240C analyser.
Melting points were reported with a PHMK melting-
point apparatus and were uncorrected.
2.2.2. [Bis(3,5-dimethyl-4-(40-pyridyl)pyrazole)]
diethyltin dichloride (3)
This compound was obtained by the reaction of 1
with Et2SnCl2. Pale-yellow solid; yield: 85%; m.p. 162–
165 ꢁC. 1H NMR (CD3SOCD3): d 8.57 (d, 4H, a-
PyH), 7.36 (d, 4H, b-PyH), 2.28 (s, 12H, CH3), 1.56
(q, 4H, SnCH2), 1.26 (t, 6H, CH2 CH3). IR:
m
Calc. for C24H32Cl2N6Sn: C, 48.52; H, 5.43; N, 14.14.
Found: C, 48.34; H, 5.28; N, 14.29%.
NH = 3262.3 (m); mpyridyl ring = 1611.7 (s) cmꢁ1. Anal.
2.2.3. [Bis(3,5-dimethyl-4-(40-pyridyl)pyrazole)]
di(n-butyl)tin dichloride (4)
2.1. Preparation of 3,5-dimethyl-4-(40-pyridyl)pyrazole
(1)
This compound was obtained by the reaction of 1
with n-Bu2SnCl2. Pale-yellow solid; yield: 78%; m.p.
152–154 ꢁC. 1H NMR (CD3SOCD3): d 8.56 (d, 4H,
a-PyH), 7.35 (d, 4H, b-PyH), 2.27 (s, 12H, CH3),
1.65–1.56 (m, 8H, SnCH2CH2), 1.36–1.24 (m, 4H,
CH2CH3), 0.87 (t, 6H, CH2CH3). 13C NMR
(CD3SOCD3): d 11.37, 13.62, 25.56, 27.76, 37.72 (car-
bons of butyl and methyl groups), 114.13, 122.41,
142.13, 149.24 (carbons of pyrazolyl and pyridyl rings).
Hydrazine hydrate (4 ml, 85%, 68 mmol) was
added to a toluene solution of raw 3-(4-pyridyl)pen-
tane-2,4-dione, obtained by the reaction of 4-methyl-
pyridine (18.2 ml, 186 mmol) with acetyl chloride
(10.6 ml, 149 mmol) according to the literature meth-
od [19], and then the mixture was stirred at room tem-
perature overnight. After removal of the solvent under
reduced pressure, the residue was recrystallized from
water to yield 1.6 g of 1 as white plate crystals,
m.p. 105–107 ꢁC. 1H NMR (CDCl3): d 8.63 (d, 2H,
a-PyH), 7.24 (d, 2H, b-PyH), 4.30 (s, br, 1H, NH),
2.37 (s, 6H, CH3). 13C NMR (CDCl3): d 11.83
(CH3), 100.00, 115.72, 123.71, 142.39, 149.55 (carbons
of pyrazolyl and pyridyl rings). IR: mNH = 3407.0 (m);
119Sn NMR (CD3SOCD3):
m
d
ꢁ214 (s, br). IR:
NH = 3250.0 (m); mpyridyl ring = 1612.9 (s) cmꢁ1. Anal.
Calc. for C28H40Cl2N6Sn: C, 51.72; H, 6.20; N, 12.92.
Found: C, 51.96; H, 6.08; N, 12.69%.
2.3. Preparation of bis[3,5-dimethyl-4-(40-pyridyl)
pyrazol-1-yl]methane (5)
m
pyridyl ring = 1605.7 (s) cmꢁ1
.
Anal. Calc. for
C10H11N3: C, 69.34; H, 6.40; N, 24.26. Found: C,
3,5-Dimethyl-4-(40-pyridyl)pyrazole (3.25 g, 18.8
mmol), dibromomethane (1.38 ml, 9.4 mmol), tetrabuty-
lammonium bromide (0.5 g, 1.6 mmol) and sodium
hydroxide (5.7 g, 142.5 mmol) were added into a mixed
solvent of water (10 ml) and benzene (50 ml). The mix-
ture was stirred and refluxed for 48 h. After cooling to
room temperature, the benzene layer was separated
and the water phase was extracted with benzene
(3 · 40 ml). The organic layers were combined and dried
by MgSO4. After evaporating the solvent, the residue
was recrystallized (charcoal treatment) from benzene
to yield 1.35 g of 5 (40%) as white crystals, m.p. 139–
140 ꢁC. 1H NMR (CDCl3): d 8.63 (d, 4H, a-PyH),
7.18 (d, 4H, b-PyH), 6.21 (s, 2H, CH2), 2.58, 2.27 (s, s,
6H, 6H, CH3). 13C NMR (CDCl3): d 10.55, 12.75
(CH3), 60.58 (CH2), 117.99, 123.95, 138.29, 141.73,
146.72, 149.97 (carbons of pyrazolyl and pyridyl rings).
IR: mpyridyl ring = 1599.7 (s) cmꢁ1. Anal. Calc. for
C21H22N6: C, 70.37; H, 6.19; N, 23.45. Found: C,
70.12; H, 6.11; N, 23.06%.
69.12; H, 6.17; N, 24.43%.
2.2. Reaction of 1 with R2SnCl2 (R = Ph, Et or n-Bu)
All reactions were carried out in a similar manner, so
a general procedure is described. To a stirred solution of
R2SnCl2 (1 mmol) in 15 ml ether at room temperature, a
solution of 1 (1 mmol) in 15 ml ether was added. The
reaction mixture was stirred continuously for 6 h at
room temperature, during which time a precipitate grad-
ually formed. The precipitate was filtered off, washed
with ether and dried in vacuo. Yields, melting points
and analytical data are given below.
2.2.1. [Bis(3,5-dimethyl-4-(40-pyridyl)pyrazole)]
diphenyltin dichloride (2)
This compound was obtained by the reaction of 1
with Ph2SnCl2. White solid; yield: 82%; m.p. 155–158
ꢁC. 1H NMR (CD3COCD3): d 8.61 (d, 4H, a-PyH),

Q. Cui et al. / Polyhedron 24 (2005) 209–214
211
2.4. Reaction of 5 with R2SnCl2 (R = Ph, Et or n-Bu)
2.5. Crystal structure determinations
A general procedure was used for all preparations.
The solution of 5 (0.5 mmol) in 10 ml CH2Cl2 was added
to the stirred solution of R2SnCl2 (0.5 mmol) in 10 ml
CH2Cl2 at room temperature. The reaction mixture
was stirred continuously for 4 h, during which time a
precipitate gradually formed. The precipitate was fil-
tered off, washed and dried in vacuo. Yields, melting
points and analytical data are given below.
Crystals of complexes 2 and 6 suitable for X-ray anal-
ysis were obtained by slowly cooling hot acetone solu-
tions of 2 and 6. Crystals of complex 2 contain one-
half of a co-crystallized acetone molecule. The methyl
carbon and oxygen atoms of the acetone molecule as
well as the hydrogen atom on the pyrazolyl nitrogen ex-
hibit disorder. Satisfactory results were obtained when
they were given occupancy factors of 0.5. Crystals of
1
complex 6 have the stoichiometry 6 ꢀ H2O ꢀ acetone,
4
2.4.1. [Bis(3,5-dimethyl-4-(40-pyridyl)pyrazol-1-yl)
methane]diphenyltin dichloride (6)
in which the phenyl group of C7–C12, pyrazolyl group
of N4–N5–C28 and pyridyl group of N6–C33 are disor-
dered, and their occupancy factors were refined to 0.594
for C7–C12 and 0.406 for C70–C120, 0.906 for N4–N5–
C28 and 0.094 for N40–N50–C280, and 0.788 for N6–C33
and 0.212 for N60–C330, respectively. The N40 atom was
refined to the same position with N4 by EXYZ and
EADP. When acetone (occupancy factor of 0.25) ap-
pears, the disordered phenyl group locates in the posi-
tion of C7–C12 (occupancy factor of 0.594). All
intensity data were collected with a Bruker SMART
CCD diffractometer, using graphite monochromated
This compound was obtained by the reaction of 5
with Ph2SnCl2. White solid; yield: 90%; m.p. 131–
133 ꢁC. 1H NMR (CD3COCD3): d 8.63 (d, 4H, a-
PyH), 7.39 (d, 4H, b-PyH), 7.96, 7.47 (m, m, 4H,
6H, C6H5), 6.34 (s, 2H, CH2), 2.65, 2.23 (s, s, 6H,
6H, CH3). IR: mpyridyl ring = 1614.7 (s) cmꢁ1. Anal.
Calc. for C33H32Cl2N6Sn: C, 56.44; H, 4.59; N,
11.97. Found: C, 56.63; H, 4.73; N, 12.06%.
2.4.2. [Bis(3,5-dimethyl-4-(40-pyridyl)pyrazol-1-yl)
methane]diethyltin dichloride (7)
˚
Mo Ka radiation (k = 0.71073 A). The structures were
This compound was obtained by the reaction of 5
with Et2SnCl2. White solid; yield: 89%; m.p. 138–140
ꢁC. 1H NMR (CD3SOCD3): d 8.59 (d, 4H, a-PyH),
7.31 (d, 4H, b-PyH), 6.31 (s, 2H, CH2), 2.56, 2.18
(s, s, 6H, 6H, CH3), 1.55 (q, 4H, SnCH2), 1.26 (t,
6H, CH2CH3). 13C NMR (CD3SOCD3): d 10.14,
10.55, 12.61, 31.79 (carbons of ethyl and methyl
groups), 59.30 (CH2), 116.66, 123.52, 137.96, 141.05,
145.82, 149.61 (carbons of pyrazolyl and pyridyl
rings). 119Sn NMR (CD3SOCD3): d ꢁ227.06 (s, br).
IR: mpyridyl ring = 1612.6 (s) cmꢁ1. Anal. Calc. for
C25H32Cl2N6Sn: C, 49.54; H, 5.32; N, 13.86. Found:
C, 49.88; H, 5.44; N, 13.87%.
resolved by the direct method and refined by full-matrix
least-squares on F2. All non-hydrogen atoms were re-
fined anisotropically. A summary of the fundamental
crystal data for complexes 2 and 6 is listed in Table 1.
Table 1
Crystal data for compounds 2 and 6
Compound
Formula
Formula weight
2 Æ 0.5CH3COCH3
C33.5H35Cl2N6O0.5Sn C33.75H35.5Cl2N6O1.25Sn
6 Æ H2O Æ 0.25CH3COCH3
719.27
734.77
Crystal size (mm) 0.26 · 0.24 · 0.20
0.30 · 0.25 · 0.20
monoclinic
P2(1)/c
Crystal class
Space group
Cell parameters
tetragonal
I-42d
2.4.3. [Bis(3,5-dimethyl-4-(40-pyridyl)pyrazol-1-yl)
methane]di(n-butyl)tin dichloride (8)
˚
a (A)
20.489(4)
20.489(4)
15.274(6)
90.00
7.820(3)
17.777(6)
29.97(1)
91.053(6)
4166(2)
4
˚
b (A)
˚
c (A)
This compound was obtained by the reaction of 5
with n-Bu2SnCl2. After the reaction was completed,
the solvent was concentrated to ca. 5 ml, then the
same volume hexane was slowly added to yield a
white solid; yield: 80%; m.p. 105–106 ꢁC. 1H NMR
(CDCl3): d 8.73 (d, 4H, a-PyH), 7.29 (d, 4H, b-
PyH), 6.23 (s, 2H, CH2), 2.62, 2.29 (s, s, 6H, 6H,
CH3), 1.84–1.66 (m, 8H, SnCH2CH2), 1.43–1.34 (m,
4H, CH2CH3), 0.92 (t, 6H, CH2CH3). 13C NMR
(CDCl3): d 10.67, 12.99, 13.53, 26.09, 27.84, 35.93
(carbons of butyl and methyl groups), 117.27,
124.41, 138.92, 144.27, 147.01, 148.16 (carbons of pyr-
azolyl and pyridyl rings). 119Sn NMR (CDCl3): d
b (ꢁ)
3
˚
V (A )
6412(3)
8
Z
T (K)
Dcalc (Mg mꢁ3
F(000)
293(2)
1.490
2928
293(2)
1.172
1496
)
˚
k (Mo Ka) (A)
0.71073
0.999
3294
0.71073
0.772
7072
l (mmꢁ1
)
Number of
reflections
measured
Number of
reflections
observed
3013
4216
(I P 2r(I))
Number of
parameters
Residuals R, Rw
ꢁ98.46, ꢁ145.68. IR: mpyridyl ring = 1621.1 (s) cmꢁ1
.
Anal. Calc. for C29H40Cl2N6Sn: C, 52.59; H, 6.09;
N, 12.69. Found: C, 52.37; H, 5.89; N, 12.63%.
224
524
0.0231, 0.0553
0.0757, 0.2049

212
Q. Cui et al. / Polyhedron 24 (2005) 209–214
3. Results and discussion
soluble in chlorinate solvents possibly because the long-
er alkyl groups increase its solubility in organic solvents.
It is well known that the d (119Sn) values in the 119Sn
NMR spectra are markedly dependent on the coordina-
tion environments around the tin atom. Owing to low
solubility, only 119Sn NMR spectra of complexes 4, 7
and 8 can be clearly observed. The 119Sn NMR signals
of 4 and 7 in CD3SOCD3 occur at ꢁ214.0 and ꢁ227.1
ppm, respectively, as broad peaks, while complex 8
exhibits two 119Sn NMR signals in CDCl3 at ꢁ98.5
and ꢁ145.7 ppm. These data indicate that these adducts
may partially dissociate in polar solutions. This kind of
dissociation equilibrium can often be observed in other
diorganotin derivatives containing N-donor ligands
[8,12,16,20].
3.1. Synthesis and characterization of complexes
Since 3-(4-pyridyl)pentane-2,4-dione is unstable [19],
the raw pyridylpentadione was directly reacted with an
excess of hydrazine hydrate to give 3,5-dimethyl-4-(40-
pyridyl)pyrazole (1) in a reasonable yield. Treatment
of this pyrazolyl ligand with R2SnCl2 (R = Ph, Et or
n-Bu) in a 1:1 ratio affords 2:1 (ligand:tin) adducts 2–4
1
(Scheme 1), according to the results of H NMR data
1
and elemental analyses. The H NMR spectra of the
complexes are consistent with the formulae of 2:1 ad-
ducts, which exhibit the expected proton signals for
two equivalent pyridylpyrazole ligands. The chemical
shifts of the protons for the ligand in the complexes
are similar to those of the free ligand. Complexes 2–4
are insoluble in ether, chlorinated solvents, slightly solu-
ble in acetone at room temperature, and moderately sol-
uble in stronger polar organic solvents such as DMF
and DMSO.
Reaction of 1 with CH2Br2 under phase-transfer con-
ditions gives the new bridging ligand bis(3,5-dimethyl-4-
(40-pyridyl)pyrazol-1-yl)methane (5). Treatment of 5
with an equimolar amount of R2SnCl2 in CH2Cl2 af-
fords 1:1 adducts 6–8. Like complexes 2–4, 6 and 7 are
insoluble in ether, chlorinated solvents, and slightly sol-
uble in acetone at room temperature, but complex 8 is
3.2. Crystal structures of complexes 2 and 6
The molecular structure of 2 has been confirmed by
X-ray diffraction analysis as shown in Fig. 1, which
clearly shows that two 3,5-dimethyl-4-(40-pyridyl)pyraz-
ole ligands coordinate to the tin atom through the pyr-
idyl nitrogen atom instead of the pyrazolyl nitrogen
atom. The pyridylpyrazole acts as a monodentate ligand
toward the tin atom, which is six-coordinate with a
slightly distorted octahedral geometry, containing two
nitrogen atoms of pyridyl groups, two phenyl carbons
as well as two chlorine atoms in an all-trans configura-
tion. The Sn–Cl and Sn–C bond distances are similar
to those in other diorganotin derivatives with monoden-
tate or bidentate N-donor ligands [8,20,21]. The average
Cl
R
NH
N
N
˚
N
N
Sn–N bond distance (2.365(3) A) in 2 is also close to
those in other diorganotin derivatives with monodentate
N-donor ligands [8], such as in Ph2SnCl2(Tz)2 (2.369(8)
Sn
HN
Cl
R
2-4
˚
A, Tz = thiazole) [20]. The dihedral angle between the
two phenyl planes is 46.2ꢁ, larger than that between
the two pyridyl planes (40.9ꢁ). The pyridyl group is
not coplanar with the pyrazolyl ring. The dihedral angle
formed by the N(1)–C(1A) pyridyl plane and the N(2)–
C(5) pyrazolyl plane is 33.0ꢁ, slightly larger than the
dihedral angle formed by the N(3)–C(7A) pyridyl plane
and the N(4)–C(11) pyrazolyl plane (30.5ꢁ).
R2SnCl2
N
N
HN
1
CH2Br2
It is also noteworthy that molecules of complex 2 are
linked into a linear chain in the solid state through inter-
molecular N–Hꢀ ꢀ ꢀN hydrogen bond interactions (Fig.
2), while bis(pyrazole) or bis(imidazole) complexes of
diorganotin dihalides tend to self-organize into chain
polymers by intermolecular N–Hꢀ ꢀ ꢀX hydrogen bond-
ing (X = Cl or Br) [22–28].
H2
C
N
N
N
N
N
N
5
R2SnCl2
Bis(3,5-dimethyl-4-(40-pyridyl)pyrazol-1-yl)methane
is a potential multidentate ligand which can act as a che-
lating multidentate ligand, like original bis(pyrazol-1-
yl)methane using the pyrazolyl nitrogens coordinated
to metals, as well as a bridging ligand by the exodentate
pyridyl nitrogens. In order to confirm the coordination
mode of this ligand with diorganotin halides, the
H2
C
N
N
N
N
SnR2Cl2
N
n
N
6-8
Scheme 1. R = Ph (2) and (6); R = Et (3) and (7); R = n-Bu (4) and (8).

Q. Cui et al. / Polyhedron 24 (2005) 209–214
213
˚
Fig. 1. The molecular structure of complex 2. The thermal ellipsoids are drawn at the 30% probability. Selected bond distances (A) and angles (ꢁ):
Sn(1)–N(1) = 2.352(3), Sn(1)–N(3) = 2.377(3), Sn(1)–C(13) = 2.177(3), Sn(1)–Cl(1A) = 2.534(1), C(3)–C(4) = 1.478(6); C(13)–Sn(1)–C(13A) =
177.0(1), N(1)–Sn(1)–N(3) = 180.0, Cl(1)–Sn(1)–Cl(1A) = 179.11(4), C(13)–Sn(1)–N(3) = 91.50(9), C(13A)–Sn(1)–Cl(1) = 89.5(1), N(1)–Sn(1)–
Cl(1A) = 89.55(2); torsion angles: C(2)–C(3)–C(4)–C(5) = 32.7(3); C(2)–C(3)–C(4)–C(5A) = ꢁ147.3(3)ꢁ (symmetry code: A = x, ꢁy + 1/2, ꢁz + 1/4).
as a bridged bidentate ligand by two exodentate pyridyl
nitrogen atoms. The coordination environment around
the tin atom is similar to that in complex 2, i.e., a slightly
distorted octahedral geometry, as well as an all-trans
configuration of pyridyl nitrogen atoms, phenyl carbons
and chlorine atoms. The Sn–Cl, Sn–C and Sn–N bond
distances are also similar to those in complex 2. The
coordination mode of ligand 5 in complex 6 with the
tin atom is analogous to those of bis(triazol-1-yl)meth-
ane [16] and pyrazine [28]. However, in the diorganotin
derivatives of bis(triazol-1-yl)methane and pyrazine, the
halide atoms as well as the coordinated nitrogen atoms
are in cis-positions.
In conclusion, the coordination modes of 4-pyridylpy-
razole and bis(4-pyridylpyrazol-1-yl)methane with diorg-
Fig. 2. The crystal packing diagram of complex 2 emphasizing the
anotin are quite different from those of the original azole
intermolecular
hydrogen
bonding
interactions
(N(2)–
Hꢀ ꢀ ꢀN(4)i = 2.984 A, N(4)–Hꢀ ꢀ ꢀN(2)ii = 2.984 A; symmetry code:
i = x ꢁ 1, ꢁy + 1/2, ꢁz + 1/4, ii = x + 1, ꢁy + 1/2, ꢁz + 1/4) and the
one-dimensional chain. The solvent molecule is omitted for clarity.
˚
˚
and 2-pyridylpyrazole as well as bis(pyrazol-1-yl)meth-
ane. In diorganotin derivatives of pyridylpyrazole, the
exodentate pyridyl nitrogen atoms have priority in coor-
dinating to the tin atom possibly owing to their stronger
donor ability over the pyrazolyl nitrogen. The coordina-
tion mode of ligand 5 to the tin atom is similar to those of
4,4-bipyridine and bis(1,2,4-triazol-1-yl)methane.
X-ray diffraction analysis of complex 6 was undertaken.
Fig. 3 shows that 6 is a 1D coordination polymer and
bis(3,5-dimethyl-4-(40-pyridyl)pyrazol-1-yl)methane acts
Fig. 3. Themolecularstructureofcomplex6.Thethermalellipsoidsaredrawnat30%probability.Thesolventmoleculesareomittedforclarity.Selectedbond
˚
distances(A)andangles(ꢁ):Sn1–Cl1 = 2.551(2),Sn1–Cl2 = 2.526(2),Sn1–N1 = 2.371(6),Sn1–N1A = 2.361(6),Sn1–C1 = 2.132(10),C15–C19 = 1.470(10),
N2–C23 = 1.452(9),C23–N4 = 1.446(9);C1–Sn1–C7 = 177.0(4),N6A–Sn1–N1 = 178.3(3),Cl1–Sn1–Cl2 = 179.37(8),N6A–Sn1–Cl1 = 89.1(1),C1–Sn1–
Cl1 = 90.2(3), C1–Sn1–Cl2 = 89.5(3), C7–Sn1–N1 = 89.0(3), C1–Sn1–N1 = 88.7(3), N4–C23–N2 = 110.9(5); torsion angles: C16–C15–C19–
C20 = 40.1(13),C16–C15–C23–C18 = ꢁ142.0(10),N3–N2–C23–N4 = ꢁ81.5(8)ꢁ(symmetrycode:A = x + 1,ꢁy + 1/2,z ꢁ 1/2).

214
Q. Cui et al. / Polyhedron 24 (2005) 209–214
[10] G.G. Lobbia, A. Cingolani, D. Leonesi, A. Lorenzotti, F. Bonati,
Inorg. Chim. Acta 130 (1987) 203.
4. Supplementary material
[11] R. Visalakshi, V.K. Jain, S.K. Kulshreshtha, G.S. Rao, Inorg.
Chim. Acta 118 (1986) 119.
Crystallographic data (CIF files) for the structures of
complexes 2 and 6 have been deposited with the Cam-
bridge Crystallographic Data Centre, CCDC No.
248284 for complex 2 and CCDC No. 248283 for com-
plex 6. Copies of this information may be obtained free
of charge from The Director, CCDC, 12 Union Road,
Cambridge, CB2 1EZ, UK (fax: +44 1223 336 033; e-
mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
[12] L.-F. Tang, Z.-H. Wang, W.-L. Jia, Y.-M. Xu, J.-T. Wang,
Polyhedron 19 (2000) 381.
[13] L.-F. Tang, P.-J. Zhu, J.-T. Wang, J. Chem. Res. (S) (2002)
370.
[14] Z.-H. Wang, L.-F. Tang, W.-L. Jia, J.-T. Wang, H.-G. Wang,
Polyhedron 21 (2002) 873.
[15] Z.-H. Wang, L.-F. Tang, J.-F. Chai, J.-T. Wang, H.-G. Wang,
Chin. J. Struct. Chem. 21 (2002) 273.
[16] L.-F. Tang, Z.-H. Wang, J.-F. Chai, W.-L. Jia, Y.-M. Xu, J.-T.
Wang, Polyhedron 19 (2000) 1949.
´ ´
[17] A. Antin˜olo, F. Carrillo-Hermosilla, E. Dıez-Barra, J. Fernan-
´
´
´
dez-Baeza, M. Fernandez-Lopez, A. Lara-Sanchez, A. Moreno,
A. Otero, A.M. Rodriguez, J. Tejeda, J. Chem. Soc., Dalton
Trans. (1998) 3737.
Acknowledgements
This work is supported by the National Natural Sci-
ence Foundation of China (No. 20172029) and the Re-
search Fund for the Doctoral Program of Higher
Education.
[18] L.-F. Tang, W.-L. Jia, Z.-H. Wang, J.-T. Wang, H.-G. Wang, J.
Organomet. Chem. 649 (2002) 152.
[19] L.G. Mackay, H.L. Anderson, J.K.M. Sanders, J. Chem. Soc.,
Perkin Trans. I (1995) 2269.
´
[20] P. Alvarez-Boo, M.D. Couce, E. Freijanes, J.S. Casas, A.
´ ´
Castin˜eiras, A. Sanchez Gonzalez, J. Sordo, U. Russo, J.
Organomet. Chem. 506 (1996) 253.
References
´
´
´
´
[21] E. Garcıa Martınez, A. Sanchez Gonzalez, J.S. Casas, J. Sordo,
U. Casellato, R. Graziani, U. Russo, J. Organomet. Chem. 463
(1993) 91.
[1] (a) A.J. Crowe, P.J. Smith, G. Atassi, Chem. Biol. Interact. 32
(1980) 171;
[22] G. Valle, E. Ettore, V. Peruzzo, G. Plazzogna, J. Organomet.
Chem. 326 (1987) 169.
(b) A.J. Crowe, P.J. Smith, G. Atassi, Inorg. Chim. Acta 93
(1984) 179.
[23] B. Alberte, A. Sanchez-Gonzalez, E.R. Garcia, E.E. Castellano,
J. Organomet. Chem. 338 (1988) 187.
[2] M. Gielen, Coord. Chem. Rev. 151 (1996) 41.
[3] A.K. Saxena, F. Huber, Coord. Chem. Rev. 95 (1989) 109.
´
[4] P. Alvarez-Boo, J.S. Casas, A. Castin˜eiras, M.D. Couce, E.
[24] A. Sanchez-Gonzalez, B. Alberte, J.S. Casas, J. Sordo, A.
Castineiras, W. Hiller, J. Stra¨hle, J. Organomet. Chem. 353
(1988) 169.
Freijanes, E. Novoa, J. Sordo, Appl. Organomet. Chem. 17
(2003) 725.
´
[5] P. Alvarez-Boo, J.S. Casas, A. Castin˜eiras, M.D. Couce, E.
[25] V. Peruzzo, G.. Plazzogna, G. Valle, J. Organomet. Chem. 375
(1989) 167.
Freijanes, A. Furlani, U. Russo, V. Scarcia, J. Sordo, M. Varela,
Inorg. Chim. Acta 353 (2003) 8.
[26] E. Garcia-Martinez, A. Sanchez-Gonzalez, A. Macias, M.V.
Castano, J.S. Casas, J. Sordo, J. Organomet. Chem. 385 (1990)
329.
[6] C. Pettinari, M. Pellei, A. Cingolani, D. Martini, A. Drozdov, S.
Troyanov, W. Panzeri, A. Mele, Inorg. Chem. 38 (1999) 5777.
[7] C. Pettinari, A. Cingolani, B. Bovio, Polyhedron 15 (1996) 115.
[8] C. Pettinari, A. Lorenzotti, G. Sclavi, A. Cingolani, E. Rivarola,
M. Colapietro, A. Cassetta, J. Organomet. Chem. 496 (1995) 69.
[9] G.G. Lobbia, F. Bonati, A. Cingolani, D. Leonesi, A. Lorenzotti,
J. Organomet. Chem. 359 (1989) 21.
[27] A. Sanchez-Gonzales, J.S. Casas, J. Sordo, G. Valle, J. Organo-
met. Chem. 435 (1992) 29.
[28] (a) D. Cunningham, J. McManus, M.J. Hynes, J. Organomet.
Chem. 393 (1990) 69;
(b) D. Cunningham, P. McArdle, J. McManus, T. Higgins, K.
Molloy, J. Chem. Soc., Dalton Trans. (1988) 2621.