Synthesis, spectroscopic, and X-ray Diffraction structural studies of tin(IV) derivatives with tris(pyrazol-1-yl)methanes

Article abstract of DOI:10.1021/ic9906252

The reaction of RSnCl₃ (R = Me, Ph, or Buⁿ) and SnX₄ acceptors (X = Cl, Br, or I) with equimolar amounts of tris(pyrazol-1-yl)methane ligands L (L = HC(pz)₃, HC(4-Mepz)₃, HC(3,5-Me₂pz)₃, HC(3,4,5-Me₃pz)₃, or HC(3-Mepz)₂(5-Mepz) yields ionic 1:1 [{LSnRCl₂}⁺][{SnRCl₄}^-] or [{LSnX₃}⁺][{SnX₅}^-] and 2:1 [{LSnRCl₂}⁺]₂[{Sn-RCl₅} ^2-] or [{LSnX₃}⁺]₂[{SnX₆}^2-] complexes, depending strongly on the number and position of the Me groups on the azole ring of the neutral ligand. These complexes, stable in air, have been characterized in the solid state (IR, MS-FAB) as well as in solution (¹H- and ¹¹⁹Sn-NMR, conductivity, and molecular weight determinations). The crystal and molecular structure of [{HC(4-Me₂pz)₃SnⁿBuCl₂} ⁺]₂[{SnⁿBuCl₅}^2-], [{HC(3,5-Me₂pz)₃SnMeCl₂} ⁺]-[{MeSnCl₄}^-], and [{HC(3,4,5-Me₃pz)₃SnBr₃} ⁺][{SnBr₅}^-] was determined by X-ray crystallography. The structures of the cations are very similar, the Sn atom being in a strongly distorted octahedral environment with the Sn-N bonds in the range 2.22-2.33 ?, whereas in the anions the Sn atoms are five-coordinate (trigonalbipyramidal) in [MeSnCl₄]^- and [SnBr₅]^- and six-coordinate (octahedral) in [SnⁿBuCl₅]^2-.

Full text of DOI:10.1021/ic9906252

Inorg. Chem. 1999, 38, 5777-5787
5777
Synthesis, Spectroscopic, and X-ray Diffraction Structural Studies of Tin(IV) Derivatives
with Tris(pyrazol-1-yl)methanes
C. Pettinari,*,† M. Pellei,† A. Cingolani,† D. Martini,† A. Drozdov,‡ S. Troyanov,‡
W. Panzeri,§ and A. Mele§
Dipartimento di Scienze Chimiche, Universita` degli Studi di Camerino, via S. Agostino 1,
I-62032 Camerino, Macerata, Italy, Department of Chemistry, Moscow State University,
Vorobjevy Gory, 119899 Moscow, Russia, and Dipartimento di Chimica del Politecnico,
via Mancinelli 7, I-20131 Milano, Italy
ReceiVed June 2, 1999
The reaction of RSnCl3 (R ) Me, Ph, or Bun) and SnX4 acceptors (X ) Cl, Br, or I) with equimolar amounts of
tris(pyrazol-1-yl)methane ligands L (L ) HC(pz)3, HC(4-Mepz)3, HC(3,5-Me2pz)3, HC(3,4,5-Me3pz)3, or HC(3-
Mepz)2(5-Mepz) yields ionic 1:1 [{LSnRCl2}+][{SnRCl4}-] or [{LSnX3}+][{SnX5}-] and 2:1 [{LSnRCl2}+]2[{Sn-
RCl5}2-] or [{LSnX3}+]2[{SnX6}2-] complexes, depending strongly on the number and position of the Me groups
on the azole ring of the neutral ligand. These complexes, stable in air, have been characterized in the solid state
(IR, MS-FAB) as well as in solution (1H- and 119Sn-NMR, conductivity, and molecular weight determinations).
The crystal and molecular structure of [{HC(4-Me2pz)3SnnBuCl2}+]2[{SnnBuCl5}2-], [{HC(3,5-Me2pz)3SnMeCl2}+]-
[{MeSnCl4}-], and [{HC(3,4,5-Me3pz)3SnBr3}+][{SnBr5}-] was determined by X-ray crystallography. The
structures of the cations are very similar, the Sn atom being in a strongly distorted octahedral environment with
the Sn-N bonds in the range 2.22-2.33 Å, whereas in the anions the Sn atoms are five-coordinate (trigonal-
bipyramidal) in [MeSnCl4]- and [SnBr5]- and six-coordinate (octahedral) in [SnnBuCl5]2-
.
Introduction
containing N-donor ligands exhibited antitumor activity. More
recently, this preliminary examination of such complexes has
been extended to a systematic study of the antitumor properties
of tin compounds,3 demonstrating4 that the coordinated N-donor
ligands favor in some way the transport of the drugs into cells;
e.g., in the case of the diorganotin(IV) compounds, the antitumor
activity arises from SnR2(IV) moieties released by slow hy-
drolysis of the complexes. In addition organotin(IV) halides
exhibit strong Lewis acidity, and their complexation chemistry
has been a subject of growing interest; these species have been
recently employed in the selective complexation of anionic and
neutral donors by tailor-made molecular hosts.5
Since poly(pyrazol-1-yl)borate ligands were discovered and
used by Trofimenko in the synthesis of main group and
transition metal derivatives,1 numerous reports of poly(pyrazol-
1-yl)borate-tin(IV) complexes have appeared.2 A driving force
for much of the chemistry in this area stems from its biological
relevance: in the 1970s, while some research was undertaken
to study the biological properties and applications of organotin
compounds, it was discovered that certain organotin derivatives
* To whom correspondence should be addressed. Fax: 0039 0737
637345. E-mail address: Pettinar@camserv.unicam.it.
† Universita` degli Studi di Camerino.
We have initiated a study on the coordination chemistry of
neutral bis- and tris(pyrazol-1-yl)alkanes with several post-
transition and transition metals.6 We are interested in contrasting
the chemistry of the neutral poly(pyrazol-1-yl)alkane ligands
‡ Moscow State University.
§ Politecnico.
(1) (a) Trofimenko, S. J. Am. Chem. Soc. 1966, 88, 1842. (b) Trofimenko,
S. J. Am. Chem. Soc. 1967, 89, 3165, 3170, 6288.
(2) (a) Gioia Lobbia, G.; Valle, G.; Calogero, S.; Cecchi, P.; Santini, C.;
Marchetti, F. J. Chem. Soc., Dalton Trans. 1996, 2475. (b) Gioia
Lobbia, G.; Bonati, F.; Cecchi, P.; Cingolani A.; Lorenzotti, A. J.
Organomet. Chem. 1989, 378, 139. (c) Gioia Lobbia, G.; Bonati, F.;
Cecchi, P.; Lorenzotti, A.; Pettinari, C. J. Organomet. Chem. 1991,
403, 317. (d) Gioia Lobbia, G.; Cecchi, P.; Spagna, R.; Colapietro,
M.; Pifferi, A.; Pettinari, C. J. Organomet. Chem. 1995, 485, 45. (e)
Gioia Lobbia, G.; Cecchi, P.; Calogero, S.; Valle, G.; Chiarini, M.;
Stievano, L. J. Organomet. Chem. 1995, 503, 297. (f) Calogero, S.;
Valle, G.; Gioia Lobbia, G.; Santini, C.; Cecchi, P.; Stievano, L. J.
Organomet. Chem. 1996, 526, 269. (g) Calogero, S.; Stievano, L.;
Gioia Lobbia, G.; Cingolani, A.; Cecchi P.; Valle, G. Polyhedron 1995,
14, 1731. (h) Gioia Lobbia, G.; Calogero, S.; Bovio, B.; Cecchi, P. J.
Organomet. Chem. 1992, 440, 27. (i) Nicholson, B. K. J. Organomet.
Chem. 1984, 265, 153. (j) Lee, S. K.; Nicholson, B. K. J. Organomet.
Chem. 1986, 309, 257. (k) Jung, O. S.; Jeong, J. H.; Sohn, Y. S. J.
Organomet. Chem. 1990, 399, 235. (l) Gioia Lobbia, G.; Bonati, F.;
Cecchi, P.; Leonesi, D. J. Organomet. Chem. 1990, 391, 155. (m)
Gioia Lobbia, G.; Cecchi, P.; Valle, G.; Calogero, S.; Santini, C. Main
Group Met. Chem. 1996, 19, 571. (n) Gioia Lobbia, G.; Cecchi, P.;
Santini, C.; Calogero, S.; Valle, G.; Wagner, F. E. J. Organomet.
Chem. 1996, 513, 139.
(3) (a) Cleare, M. J. Coord. Chem. ReV. 1974, 12, 349. (b) Crowe, A. J.;
Smith P. J.; Atassi, G. Chem. Ind. 1980, 200. (c) Crowe, A. J.; Smith
P. J.; Atassi, G. Chem. Biol. Interact. 1980, 32, 171.
(4) Ruisi, G.; Silvestri, A.; Lo Giudice, M. T.; Barbieri, R.; Atassi, G.;
Huber, F.; Gra¨tz, K.; Lamartina, L. J. Inorg. Biochem. 1985, 25, 229.
(5) (a) Jurkschat, K.; Hesselbarth, F.; Dargatz, M.; Lehmann, J.; Kleinpeter,
E.; Tzschach, A.; Meunier-Piret, J. J. Organomet. Chem. 1990, 388,
259. (b) Tsagatakis, J. K.; Chaniotakis, N. A.; Jurkschat, K. HelV.
Chim. Acta 1994, 77, 2191. (c) Altmann, R.; Jurkschat, K.; Schu¨rmann,
M.; Dakternieks, D.; Duthie, A. Organometallics 1998, 17, 5858. (d)
Dakternieks, D.; Jurkschat, K.; Zhu, H.; Tiekink, E. R. T. Organo-
metallics 1995, 14, 2512.
(6) (a) Lorenzotti, A.; Cingolani, A.; Gioia Lobbia, G.; Leonesi, D.; Bonati,
F. Gazz. Chim. Ital. 1987, 117, 191. (b) Cingolani, A., Lorenzotti,
A.; Gioia Lobbia G.; Leonesi, D.; Bonati, F.; Bovio, B. Inorg. Chim.
Acta 1987, 132, 167. (c) Bovio, B.; Cingolani A.; Pettinari, C.; Gioia
Lobbia G.; Bonati, F. Z. Anorg. Allg. Chem. 1991, 602, 169. (d) Bonati,
F.; Cingolani, A.; Gioia Lobbia, G.; Leonesi, D.; Lorenzotti, A.;
Pettinari, C. Gazz. Chim. Ital. 1990, 120, 341. (e) Pettinari, C.;
Lorenzotti, A.; Cingolani, A.; Leonesi, D.; Marra, M.; Marchetti, F.,
Gazz. Chim. Ital. 1993, 123, 481.
10.1021/ic9906252 CCC: $18.00 © 1999 American Chemical Society
Published on Web 11/19/1999

5778 Inorganic Chemistry, Vol. 38, No. 25, 1999
Pettinari et al.
multiplet, mc; broad, br. FAB mass spectra were obtained on a Finnigan-
MAT TSQ70 triple-stage quadrupole instrument equipped with an Ion
Tech (Teddington, U.K.) atom gun using Xe as bombarding gas. The
emission current was typically set at 2 mA with an accelerating voltage
of 8 keV. For all experiments the source was kept at room temperature,
using CsI for mass calibration. Samples were directly dissolved in an
m-nitrobenzyl alcohol matrix. Melting points are uncorrected and were
carried out using an IA 8100 Electrothermal Instrument and on a
capillary apparatus. The electrical conductance of the solutions was
measured with a Crison CDTM 522 conductimeter at room temperature.
The osmometric measurements were carried out at 40 °C, over a range
of concentrations, with a Knauer KNA0280 vapor pressure osmometer
calibrated with benzil using Baker Analyzed spectrophotometric grade
chloroform as solvent, the results being reproducible to (2%.
Preparation of the Ligands. (a) Tris(pyrazol-1-yl)methane,
HC(pz)3. The ligand HC(pz)3 (44% yield) was obtained according to
a published method:11 mp (n-hexane), 104-106 °C. 1H NMR (CDCl3,
300 MHz): δ 6.37 (pt, 3H, 4-CH), 7.58 (d, 3H, 3- or 5-CH), 7.68 (d,
Figure 1. Molecular structure of the tris(pyrazol-1-yl)methane ligands
employed in this work.
with that previously developed for anionic poly(pyrazol-1-yl)-
borates. In our previous papers, we described the interaction
between several tin(IV) and organotin(IV) acceptors and the
N2-donors H2C(pz)2,7 H2C(3,5-Me2pz)2,8 Me2C(pz)2,8,9 H2C(4-
Mepz)2,10 H2C(3,4,5-Me3pz)2,10 (H2C)2(pz)2,10 and (H2C)2(3,5-
Me2pz)2,10 showing that different reaction patterns can take place
depending on the nature of the donor and of the tin(IV) acceptor.
To gain insight into the factors controlling the structure and
bonding in these complexes, we have also determined the X-ray
crystal structure of [H2C(4-Mepz)2SnMe2Cl2].10
As an extension of our research, we have now decided to
investigate the donor ability of neutral, tris-chelating, flexible
and stable N3-donor tris(pyrazol-1-yl)methanes toward tin(IV)
and organotin(IV) acceptors. With the aim of evaluating the
influence of the substituents on the structure and properties of
the tin(IV) complexes, we have prepared a series of ligands
containing methyl groups in the 3-, 4-, and 5-positions of the
pyrazole ring: HC(pz)3, HC(4-Mepz)3, HC(3,5-Me2pz)3,
HC(3,4,5-Me3pz)3, or HC(3-Mepz)2(5-Mepz) (Figure 1) report-
ing here the syntheses and properties of 27 new complexes.
For the derivatives [{HC(3,5-Me2pz)3MeSnCl2}+][{MeSnCl4}-],
[{HC(4-Me2pz)3SnnBuCl2}+]2 [{SnnBuCl5}2-], and [{HC(3,4,5-
Me3pz)3SnBr3}+][{SnBr5}-], the crystal and molecular struc-
tures have been determined by X-ray crystallography.
1
3H, 3- or 5-CH), 8.43 (s, 1H, CH). H NMR (acetone, 300 MHz): δ
6.40 (pt, 3H, 4-CH), 7.63 (d, 3H, 3- or 5-CH), 7.86 (d, 3H, 3- or 5-CH),
8.74 (s, 1H, CH). 1H NMR (CD3OD, 300 MHz): δ 6.43 (t, 3H, 4-CH),
7.67 (d, 3H, 3- or 5-CH), 7.74 (d, 3H, 3- or 5-CH), 8.70 (s, 1H, CH).
Anal. Calcd for C10H10N6: C, 56.1; H, 4.7; N, 39.2. Found: 56.3; H,
4.8; N, 39.0. IR (cm-1): 3147 w, 3123 w [ν(C-H)].
(b) Tris(3,5-dimethylpyrazol-1-yl)methane, HC(3,5-Me2pz)3. The
ligand HC(3,5-Me2pz)3 (42% yield) was obtained according to a
1
published method:11 mp (n-hexane), 133-134 °C. H NMR (CDCl3,
300 MHz): δ 2.01 (s, 9H, 3- or 5-CH3), 2.18 (s, 9H, 3- or 5-CH3),
5.88 (s, 3H, 4-CH), 8.09 (s, 1H, CH). Anal. Calcd for C16H22N6: C,
64.4; H, 7.4; N, 28.2. Found: 64.3; H, 7.5; N, 28.0. IR (cm-1): 3165
w [ν(C-H)].
(c) Tris(3,4,5-trimethylpyrazol-1-yl)methane, HC(3,4,5-Me3pz)3.
To a stirred chloroform solution (200 mL) of 3,4,5-trimethylpyrazole
(9.6 g, 0.086 mol), prepared according to a published method,12 at room
temperature and under nitrogen, K2CO3 (60.0 g, 0.436 mol) and
n-Bu4NHSO4 (1.5 g, 0.004 mol) were added. The reaction was carried
out at 40 °C, under nitrogen and with stirring for 3 days, until the
solution became orange-red. The residue was filtered off and washed
with hot chloroform (2 × 80 mL). The organic layer was collected,
the chloroform was removed under reduced pressure, and then diethyl
ether (100 mL) was added to the residue. The colorless precipitate
formed was separated by filtration, washed with diethyl ether, and
recrystallized from n-hexane to give 3.9 g (40% yield) of HC(3,4,5-
1
Me3pz)3: mp (n-hexane), 156-157 °C. H NMR (CDCl3, 300 MHz):
δ 1.88 (s, 9H, 3- or 5-CH3), 1.93 (s, 9H, 3- or 5-CH3), 2.13 (s, 9H,
Experimental Section
1
4-CH3), 8.05 (s, 1H, CH). H NMR (CD3OD, 300 MHz): δ 1.92 (s,
General Procedures. The organotin(IV) halides were purchased
from Alfa (Karlsruhe) and Aldrich (Milwaukee) and used as received.
Solvent evaporations were always carried out under vacuum using a
rotary evaporator. The samples for microanalysis were dried in vacuo
to constant weight (20 °C, ca. 0.1 Torr). All syntheses were carried
out under a nitrogen atmosphere. Hydrocarbon solvents were dried by
refluxing with sodium, dichloromethane with calcium hydride, and
tetrahydrofuran with sodium and benzophenone and then distillated.
Prior to use all solvents were degassed under dry nitrogen.
18H, 3- and 5-CH3), 2.12 (s, 9H, 4-CH3), 8.09 (s, 1H, CH). Anal. Calcd
for C19H28N6: C, 67.0; H, 8.3; N, 24.7. Found: 66.6; H, 8.6; N, 24.6.
IR (cm-1): 3168 br [ν(C-H)].
(d) Tris(4-methylpyrazol-1-yl)methane, HC(4-Mepz)3. The ligand
HC(4-Mepz)3 (94% yield) was prepared as HC(3,4,5-Me3pz)3 by using
4-MepzH (20.3 g, 0.247 mol), K2CO3 (165.8 g, 1.200 mol), and
n-Bu4NHSO4 (4.1 g, 0.012 mol): mp (n-hexane), 149-151 °C. 1H
NMR (CDCl3, 300 MHz): δ 2.06 (s, 9H, 4-CH3), 7.30 (s, 3H, 3- or
5-CH), 7.46 (s, 3H, 3- or 5-CH), 8.17 (s, 1H, CH). 1H NMR (CD3OD,
300 MHz): δ 2.07 (s, 9H, 4-CH3), 7.44 (s, 3H, 3- or 5-CH), 7.47 (s,
3H, 3- or 5-CH), 8.36 (s, 1H, CH). Anal. Calcd for C13H16N6: C, 59.6;
H, 6.4; N, 32.0. Found: 60.0; H, 6.7; N, 31.7. IR (cm-1): 3158 w,
3128 w, 3095 w, 3074 w [ν(C-H)].
(e) Bis(3-methylpyrazol-1-yl)(5-methylpyrazol-1-yl)methane, HC(3-
Mepz)2(5-Mepz). To a stirred chloroform solution (240 mL) of
3-MepzH (16.0 g, 0.195 mol), at room temperature and under nitrogen,
K2CO3 (134.7 g, 0.975 mol) and n-Bu4NHSO4 (3.3 g, 0.010 mol) were
added. The reaction was carried out at 40 °C, under nitrogen and with
stirring for 4 days, until the solution became orange-red. The residue
was filtered off and washed with hot chloroform (2 × 80 mL). The
organic layer was collected and the solvent removed under reduced
Elemental analyses (C, H, N, S) were performed in house using a
Carlo-Erba model 1106 instrument. IR spectra were recorded from 4000
1
to 100 cm-1 with a Perkin-Elmer system 2000 FT-IR instrument. H
and 119Sn NMR spectra were recorded on a VXR-300 Varian
spectrometer operating at room temperature (300 MHz for 1H and 111.9
MHz for 119Sn). The chemical shifts (δ) are reported in parts per million
(ppm) from SiMe4 (1H calibration by internal deuterium solvent lock)
and SnMe4 (
119Sn). Peak multiplicities are abbreviated as follows:
singlet, s; doublet, d; triplet, t; multiplet, m; pseudotriplet, pt; complex
(7) Gioia Lobbia, G.; Cingolani, A.; Leonesi, D.; Lorenzotti, A.; Bonati,
F. Inorg. Chim. Acta 1987, 130, 203.
(8) Gioia Lobbia, G.; Bonati, F.; Cingolani, A.; Leonesi D.; Lorenzotti,
A. J. Organomet. Chem. 1989, 359, 21.
(9) Pettinari, C.; Cingolani, A.; Bovio, B. Polyhedron 1996, 15, 115.
(10) Pettinari, C.; Lorenzotti, A.; Sclavi, G.; Cingolani, A.; Rivarola, E.;
Colapietro M.; Cassetta, A. J. Organomet. Chem. 1995, 496, 69.
(11) Trofimenko, S. J. Am. Chem. Soc. 1970, 92, 5118.
(12) Pettinari, C.; Lorenzotti, A.; Pellei, M.; Santini, C. Polyhedron 1997,
16, 3435 and references cited therein.

Sn(IV) Derivatives with Tris(pyrazol-1-yl)methanes
Inorganic Chemistry, Vol. 38, No. 25, 1999 5779
pressure. After the addition of diethyl ether a colorless precipitate
formed. It was filtered off, washed with diethyl ether, and recrystallized
from n-hexane to give 2.9 g (17% yield) of HC(3-Mepz)2(5-Mepz):
mp (n-hexane), 114-115 °C. 1H NMR (CDCl3, 300 MHz): δ 2.27 (s,
6H, 3-CH3), 2.39 (s, 3H, 5-CH3), 6.10 (s, 3H, 4-CH), 7.31 (s, 2H, 5-CH),
7.54 (s, 1H, 3-CH), 8.21 (s, 1H, CH). Anal. Calcd for C13H16N6: C,
60.9; H, 6.3; N, 32.8. Found: 60.9; H, 6.6; N, 32.7. IR (cm-1): 3143
br, 3120 m [ν(C-H)].
isotopic cluster), 295 ([SnCl5]-, 35%, center of isotopic cluster). Anal.
Calcd for C38H35Cl9N12Sn3: C, 34.2; H, 2.6; N, 12.6. Found: C, 34.8;
H, 2.9; N, 12.3. IR (cm-1): 3129 w, 3111 w [ν(C-H)], 264 s [ν(Sn-
C)], 311 s [ν(Sn-Cl)], 399 m [δ(Ph)].
(d) [{HC(4-Mepz)3SnMeCl2}+]2[{SnMeCl5}2-], 4. Compound 4
(78% yield) was obtained similarly to compound 1: mp (CH2Cl2, diethyl
ether), 120-132 °C. 1H NMR (CDCl3, 300 MHz): δ 1.44 (s, 6H, Sn-
2
2
CH3, J(119Sn-1H) ) 113.9 Hz, J(117Sn-1H) ) 108.7 Hz), 1.92 (s,
3H, Sn-CH3, J(119Sn-1H) ) 126.9 Hz, J(117Sn-1H) ) 121.1 Hz),
2.13 (s, 9H, 4-CH3), 2.16 (s, 9H, 4-CH3), 7.80 (s, 4H, 3- or 5-CH),
8.09 (s, 2H, 3- or 5-CH), 8.85 (s, 2H, 3- or 5-CH), 8.97 (s, 4H, 3- or
5-CH), 10.19 (s, 2H, CH). 119Sn NMR (CDCl3, 111.9 MHz): δ -455.5.
Cond. (CH2Cl2, concentration ) 0.99 × 10-3 M): Λ 15.0 Ω-1 cm2
mol-1. Cond. (acetone, concentration ) 0.96 × 10-3 M): Λ 73.0 Ω-1
cm2 mol-1. Anal. Calcd for C29H41Cl9N12Sn3: C, 28.3; H, 3.3; N, 13.6.
Found: C, 28.6; H, 3.5; N, 13.3. IR (cm-1): 3150 w, 3112 m [ν(C-
H)], 536 m [ν(Sn-C)], 326 s, 310 sh [ν(Sn-Cl)].
2
2
Synthesis of the Complexes. (a) [{HC(pz)3SnMeCl2}+]2[{SnMe-
Cl5}2-, 1. To a stirred diethyl ether solution (30 mL) of HC(pz)3 (0.070
g, 0.330 mmol) at room temperature and under nitrogen, SnMeCl3
(0.120 g, 0.500 mmol) was added. After ca. 1 h, the colorless precipitate
formed was filtered off and washed with diethyl ether to give (88%
yield) the analytical sample 1: mp (CH2Cl2, diethyl ether), 256 °C
(dec.). 1H NMR (CDCl3, 300 MHz): δ 1.50 (s, 6H, Sn-CH3, 2J(119Sn-
2
1H) ) 125.0 Hz, J(117Sn-1H) ) 115.3 Hz), 1.91 (s, 3H, Sn-CH3,
2J(119Sn-1H) ) 119.6 Hz, 2J(117Sn-1H) ) 110.0 Hz), 6.40, 6.58, 6.62
(3 t, 6H, 4-CH), 7.62, 7.71, 8.03, 8.32, 9.25, 9.36 (6 d, 12H, 3- and
(e) [{HC(4-Mepz)3SnnBuCl2}+]2[{SnnBuCl5}2-], 5. Compound 5
(85% yield) was obtained similarly to compound 2: mp (CH2Cl2, diethyl
ether), 97-100 °C. H NMR (CDCl3, 300 MHz): δ 0.98, 1.01 (2 t,
1
5-CH), 8.53, 10.44 (2 s, 2H, CH). H NMR (acetone, 300 MHz): δ
1
1.57 (s, 6H, Sn-CH3, 2J(119Sn-1H) ) 120.3 Hz, 2J(117Sn-1H) ) 114.7
Hz), 1.62 (s, 3H, Sn-CH3, 2J(119Sn-1H) ) 120.7 Hz, 2J(117Sn-1H) )
115.5 Hz), 6.40, 6.86 (2 t, 6H, 4-CH), 7.63, 7.86 (2 d, 6H, 3- or 5-CH),
8.56, 8.78 (2 s br, 6H, 3- or 5-CH), 8.74, 10.21 (2 s, 2H, CH). 119Sn
NMR (CDCl3, 111.9 MHz): δ -448.6. Cond. (CH2Cl2, concentration
) 1.09 × 10-3 M): Λ 0.30 Ω-1 cm2 mol-1. Cond. (acetone,
concentration ) 1.01 × 10-3 M): Λ 57.8 Ω-1 cm2 mol-1. MS (FAB-
positive): m/z 419 ([{HC(pz)3SnMeCl2}]+, 85%, center of isotopic
cluster). MS (FAB-negative): m/z 295 ([SnCl5]-, 50%, center of
isotopic cluster), 275 ([SnMeCl4]-, 25%, center of isotopic cluster).
Anal. Calcd for C23H29Cl9N12Sn3: C, 24.0; H, 2.5; N, 14.6. Found: C,
24.1; H, 2.6; N, 14.4. IR (cm-1): 3152 w, 3128 w [ν(C-H)], 545 m,
525 m [ν(Sn-C)], 315 s [ν(Sn-Cl)].
9H, Sn-nBu), 1.55 (m, 12H, Sn-nBu), 1.80-2.03 (mc, 4H, Sn-nBu),
1.91 (s, 6H, 4-CH3), 2.12 (s, 6H, 4-CH3), 2.15 (s, 6H, 4-CH3), 2.48 (t,
2H, Sn-nBu), 7.30, 7.47, 7.77, 8.09, 8.84, 8.96 (6s, 12H, 3- or 5-CH),
8.16, 10.24 (2s, 2H, CH). Cond. (CH2Cl2, concentration ) 1.11 × 10-3
M): Λ 3.2 Ω-1 cm2 mol-1. Cond. (acetone, concentration ) 0.92 ×
10-3 M): Λ 64.4 Ω-1 cm2 mol-1. Anal. Calcd for C38H59Cl9N12Sn3:
C, 33.6; H, 4.4; N, 12.4. Found: C, 33.7; H, 4.6; N, 12.1. IR (cm-1):
3120 w, 3104 m [ν(C-H)], 602 s [ν(Sn-C)], 312 s [ν(Sn-Cl)].
(f) [{HC(4-Mepz)3SnPhCl2}+]2[{SnPhCl5}2-], 6. Compound 6
(76% yield) was obtained similarly to compound 3: mp (CH2Cl2, diethyl
1
ether), 128-130 °C. H NMR (CDCl3, 300 MHz): δ 2.08 (s, 12H,
4-CH3), 2.14 (s, 6H, 4-CH3), 7.30-7.60 (mc, 12H, SnPh), 7.52 (s, 4H,
3- or 5-CH), 8.16 (s, 2H, CH), 8.32 (d, 3H, SnPh), 8.92 (s, 2H, 3- or
5-CH), 9.03 (s, 4H, 3- or 5-CH), 10.36 (s, 2H, CH). 119Sn NMR (CDCl3,
111.9 MHz): δ -469.5. Cond. (CH2Cl2, concentration ) 1.02 × 10-3
M): Λ 3.5 Ω-1 cm2 mol-1. Cond. (acetone, concentration ) 1.07 ×
10-3 M): Λ 68.7 Ω-1 cm2 mol-1. MW (CHCl3, concentration ) 2.32
× 103 M, room temperature): 464. MW (CHCl3, concentration ) 4.90
× 103 M, room temperature): 560. Anal. Calcd for C44H47Cl9N12Sn3:
C, 37.2; H, 3.3; N, 11.8. Found: C, 37.6; H, 3.6; N, 11.3. IR (cm-1):
3123 w, 3112 m, 3068 w, 3048 w [ν(C-H)], 292 m [ν(Sn-C)], 325
s [ν(Sn-Cl)], 460 s, 451 s [ν(Ph)].
(b) [{HC(pz)3SnnBuCl2}+]2[{SnnBuCl5}2-], 2. To a stirred diethyl
ether solution (30 mL) of HC(pz)3 (0.073 g, 0.340 mmol), at room
temperature and under nitrogen, SnnBuCl3 (0.147 g, 0.521 mmol) was
added. After ca. 6 h, a colorless precipitate formed which was filtered
off and washed with diethyl ether to give (86% yield) the analytical
sample 2: mp (CH2Cl2, diethyl ether), 139-141 °C. 1H NMR (CDCl3,
300 MHz): δ 0.98, 1.00 (2 t, 9H, Sn-nBu), 1.4-1.6, 1.8-2.0 (mc,
14H, Sn-nBu), 2.47 (t, 4H, Sn-nBu), 6.37, 6.56, 6.58 (3 t, 6H, 4-CH),
7.59, 7.69, 8.00, 8.32, 9.23, 9.34 (6 d, 12H, 3- and 5-CH), 8.45, 10.33
1
(2 s, 2H, CH). H NMR (acetone, 300 MHz): δ 0.95, 0.98 (2 t, 9H,
Sn-nBu), 1.49 (ps, 6H, Sn-nBu), 1.8-2.0 (mc, 6H, Sn-nBu), 2.1-
2.4 (mc, 6H, Sn-nBu), 6.40, 6.85 (2 t, 6H, 4-CH), 7.63, 7.86, 8.54,
8.81 (4 d, 12H, 3- and 5-CH), 8.73, 10.19 (2 s, 2H, CH). 119Sn NMR
(CDCl3, 111.9 MHz): δ -453.3. Cond. (CH2Cl2, concentration ) 1.21
× 10-3 M): Λ 0.40 Ω-1 cm2 mol-1. Cond. (acetone, concentration )
1.04 × 10-3 M): Λ 31.9 Ω-1 cm2 mol-1. MS (FAB-positive): m/z
461 ([{HC(pz)3SnnBuCl2}]+, 90%, center of isotopic cluster). MS (FAB-
negative): m/z 317 ([SnnBuCl4]-, 70%, center of isotopic cluster), 295
([SnCl5]-, 20%, center of isotopic cluster). Anal. Calcd for C32H47-
Cl9N12Sn3: C, 30.1; H, 3.7; N, 13.2. Found: C, 30.5; H, 3.9; N, 13.3.
IR (cm-1): 3131 w, 3107 m [ν(C-H)], 590 m [ν(Sn-C)], 300 s [ν(Sn-
Cl)].
(g) [{HC(3,5-Me2pz)3SnMeCl2}+][{SnMeCl4}-], 7. Compound 7
(95% yield) was obtained similarly to compound 1: mp (CH2Cl2, diethyl
ether), 220-223 °C. 1H NMR (CDCl3, 300 MHz): δ 1.62 (s, 3H, Sn-
2
2
CH3, J(119Sn-1H) ) 116.8 Hz, J(117Sn-1H) ) 115.1 Hz), 1.64 (s,
3H, Sn-CH3, J(119Sn-1H) ) 111.6 Hz, J(117Sn-1H) ) 110.0 Hz),
2.63 (s, 6H, 3- or 5-CH3), 2.79 (s, 3H, 3- or 5-CH3), 2.82 (s, 9H, 3- or
5-CH3), 6.21 (s, 1H, 4-CH), 6.27 (s, 2H, 4-CH), 8.09 (s, 1H, CH).
119Sn NMR (CDCl3, 111.9 MHz): δ -244.0, -469.7. Cond. (CH2Cl2,
concentration ) 1.02 × 10-3 M): Λ 19.6 Ω-1 cm2 mol-1. Cond.
2
2
(acetone, concentration ) 0.95 × 10-3 M): Λ 74.7 Ω-1 cm2 mol-1
.
Anal. Calcd for C18H28Cl6N6Sn2: C, 27.8; H, 3.6; N, 10.8. Found: C,
28.0; H, 3.8; N, 10.7. IR (cm-1): 3132 w, 3095 w [ν(C-H)], 539 m,
533 sh [ν(Sn-C)], 308 s [ν(Sn-Cl)].
(c) [{HC(pz)3SnPhCl2}+]2[{SnPhCl5}2-], 3. To a stirred diethyl
ether solution (30 mL) of HC(pz)3 (0.073 g, 0.340 mmol), at room
temperature and under nitrogen, SnPhCl3 (0.150 g, 0.496 mmol) was
added. After 2 h, the colorless precipitate afforded was filtered off and
washed with diethyl ether to give (88% yield) the analytical sample 3:
mp (CH2Cl2, diethyl ether), 204-206 °C. 1H NMR (CDCl3, 300
MHz): δ 6.40, 6.53, 6.59 (3 t, 6H, 4-CH), 7.3-7.5, 7.7-8.0 (mc, 15H,
SnPh), 7.61, 7.70, 8.19, 8.40, 9.35, 9.45 (6 d, 12H, 3- and 5-CH), 8.55,
(h) [{HC(3,5-Me2pz)3SnnBuCl2}+][{SnnBuCl4}-]‚2H2O, 8. Com-
pound 8 (85% yield) was obtained similarly to compound 2: mp
1
(CH2Cl2, diethyl ether), 59-61 °C. H NMR (CDCl3, 300 MHz): δ
0.95 (t, 3H, Sn-nBu), 0.98 (t, 3H, Sn-nBu), 1.48 (ps, 4H, Sn-nBu),
1.7-1.9 (mc, 4H, Sn-nBu), 2.04 (t, 2H, Sn-nBu), 2.19 (t, 2H, Sn-
nBu), 2.43, 2.61, 2.78, 2.81, 2.85 (5 s, 18H, 3- and 5-CH3), 4.80 (br,
4H, H2O), 6.19 (s, 1H, 4-CH), 6.26 (s, 2H, 4-CH), 8.13 (s, 1H, CH).
119Sn NMR (CDCl3, 111.9 MHz): δ -108.5, -467.5. Cond. (CH2Cl2,
concentration ) 0.76 × 10-3 M): Λ 16.1 Ω-1 cm2 mol-1. Cond.
1
10.62 (2 s broad, 2H, CH). H NMR (acetone, 300 MHz): δ 6.40,
6.88 (2 t, 6H, 4-CH), 7.38-7.60, 8.10-8.20 (mc, 15H, SnPh), 7.65,
7.90, 8.85, 8.90 (4 d, 12H, 3- and 5-CH), 8.62, 10.32 (2 s, 2H, CH).
119Sn NMR (CDCl3, 111.9 MHz): δ -503.3. Cond. (CH2Cl2, concen-
tration ) 1.06 × 10-3 M): Λ 0.11 Ω-1 cm2 mol-1. Cond. (acetone,
concentration ) 0.75 × 10-3 M): Λ 69.2 Ω-1 cm2 mol-1. MW (CHCl3,
concentration ) 3.19 × 103 M, room temperature): 643. MS (FAB-
positive): m/z 523 ([{HC(pz)3SnPhCl2}]+, 100%, center of isotopic
cluster). MS (FAB-negative): m/z 337 ([SnPhCl4]-, 40%, center of
(acetone, concentration ) 0.75 × 10-3 M): Λ 7.84 Ω-1 cm2 mol-1
.
Anal. Calcd for C24H44Cl6N6O2Sn2: C, 32.1; H, 4.9; N, 9.4. Found:
C, 31.9; H, 5.1; N, 8.8. IR (cm-1): 3164 w [ν(C-H)], 608 m, 594 m
[ν(Sn-C)], 304 s, 278 s [ν(Sn-Cl)], 3400 br [ν(H2O)].
(i) [{HC(3,5-Me2pz)3SnPhCl2}+][{SnPhCl4}-], 9. Compound 9
(76% yield) was obtained similarly to compound 3: mp (CH2Cl2, diethyl
1
ether), 176-179 °C. H NMR (CDCl3, 300 MHz): δ 1.95 (s, 6H, 3-

5780 Inorganic Chemistry, Vol. 38, No. 25, 1999
Pettinari et al.
1
or 5-CH3), 2.79 (s, 3H, 3- or 5-CH3), 2.87 (s, 9H, 3- or 5-CH3), 6.16
(s, 2H, 4-CH), 6.23 (s, 1H, 4-CH), 7.40-7.48 (mc, 8H, SnPh), 8.20
(s, 1H, CH), 8.25 (d, 2H, SnPh). 119Sn NMR (CDCl3, 111.9 MHz): δ
-320.2, -424.8. Cond. (CH2Cl2, concentration ) 0.96 × 10-3 M): Λ
17.7 Ω-1 cm2 mol-1. Cond. (acetone, concentration ) 1.02 × 10-3
M): Λ 76.8 Ω-1 cm2 mol-1. MW (CHCl3, concentration ) 3.06 ×
103 M, room temperature): 556. Anal. Calcd for C28H32Cl6N6Sn2: C,
38.3; H, 3.8; N, 9.3. Found: C, 37.9; H, 3.8; N, 9.5. IR (cm-1): 3138
w, 3102 w, 3054 w [ν(C-H)], 283 s [ν(Sn-C)], 320 s [ν(Sn-Cl)],
447 s [ν(Ph)].
(CH2Cl2, diethyl ether), 203 °C (dec.). H NMR (CDCl3, 300 MHz):
δ 1.62 (br, 2H, H2O), 1.98, 2.17, 224, 2.27 (4s, 12H, 3- or 5-CH3),
2.88, 2.95, 3.03 (3s, 6H, 3- or 5-CH3), 6.12, 6.27, 6.39, 6.40 (4s, 6H,
4-CH), 7.20-7.50 (mc, 12H, SnPh), 8.21 (d, 3H, SnPh), 8.39, 9.23 (2
d, 6H, 3- or 5-CH), 10.50, 10.60 (2 s, 2H, CH). 119Sn NMR (CDCl3,
111.9 MHz): δ -516.7, -518.8. Cond. (CH2Cl2, concentration ) 1.02
× 10-3 M): Λ 1.51 Ω-1 cm2 mol-1. Cond. (acetone, concentration )
0.85 × 10-3 M): Λ 103.3 Ω-1 cm2 mol-1. Anal. Calcd for C44H47-
Cl9N12Sn3: C, 37.2; H, 3.3; N, 11.8. Found: C, 37.3; H, 3.6; N, 11.9.
IR (cm-1): 3125 br [ν(C-H)], 292 sh [ν(Sn-C)], 309 s [ν(Sn-Cl)],
456 m [ν(Ph)].
(j) [{HC(3,4,5-Me3pz)3SnMeCl2}+][{SnMeCl4}-], 10. Compound
10 (82% yield) was obtained similarly to compound 1: mp (CH2Cl2,
(o) [{HC(pz)3SnCl3}+]2[{SnCl6}2-]‚H2O, 15. To a stirred dichlo-
romethane solution (10 mL) of HC(pz)3 (0.073 g, 0.340 mmol), at -40
°C and under nitrogen, a 1.0 M solution of SnCl4 in the same solvent
(1.0 mL) was added. After ca. 3 h, the colorless precipitate obtained
was filtered off and washed with diethyl ether to give (97% yield) the
1
diethyl ether), 128-129 °C. H NMR (CDCl3, 300 MHz): δ 1.59 (s,
2
2
6H, Sn-CH3, J(119Sn-1H) ) 115.4 Hz, J(117Sn-1H) ) 110.3 Hz),
1.99 (s, 9H, 3- or 5-CH3), 2.52 (s, 6H, 3- or 5-CH3), 2.69 (s, 3H, 3- or
5-CH3), 2.73 (s, 9H, 4-CH3), 8.16 (s, 1H, CH). 119Sn NMR (CDCl3,
111.9 MHz): δ -259.6, -474.6, -475.7. Cond. (CH2Cl2, concentration
) 0.97 × 10-3 M): Λ 21.2 Ω-1 cm2 mol-1. Cond. (acetone,
concentration ) 0.97 × 10-3 M): Λ 105.5 Ω-1 cm2 mol-1. MS (FAB-
positive): m/z 545 ([{HC(3,4,5-Me3pz)3SnMeCl2}]+, 100%, center of
isotopic cluster). MS (FAB-negative): m/z 275 ([SnMeCl4]-, 40%,
center of isotopic cluster). Anal. Calcd for C21H34Cl6N6Sn2: C, 30.7;
H, 4.2; N, 10.2. Found: C, 31.1; H, 4.4; N, 10.4. IR (cm-1): 3124 w
[ν(C-H)], 544 m [ν(Sn-C)], 312 s [ν(Sn-Cl)].
1
analytical sample 15: mp (CH2Cl2, diethyl ether), 286 °C (dec.). H
NMR (CD3OD, 300 MHz): δ 1.86 (br, 2H, H2O), 6.43 (pt, 6H, 4-CH),
7.67, 7.73 (2 d, 12H, 3- and 5-CH), 8.69 (s, 2H, CH). 119Sn NMR
(CDCl3, 111.9 MHz): δ -611.8. Cond. (acetone, concentration ) 1.04
× 10-3 M): Λ 58.9 Ω-1 cm2 mol-1. Anal. Calcd for C20H22Cl12N12-
OSn3: C, 19.8; H, 1.7; N, 13.9. Found: C, 19.5; H, 1.8; N, 13.4. IR
(cm-1): 3110 w [ν(C-H)], 349 s [ν(Sn-Cl)], 3429 br [ν(H2O)].
(p) [{HC(pz)3SnBr3}+]2[{SnBr6}2-], 16. To a stirred dichloro-
methane solution (10 mL) of HC(pz)3 (0.070 g, 0.330 mmol), at -40
°C and under nitrogen, a 1.0 M solution of SnBr4 in the same solvent
(1.0 mL) was added. After 4 h, the yellow precipitate formed was
filtered off and washed with diethyl ether to give (97% yield) the
(k) [{HC(3,4,5-Me3pz)3SnnBuCl2}+][{SnnBuCl4}-], 11. Compound
11 (79% yield) was obtained similarly to compound 1: mp (CH2Cl2,
diethyl ether), 138-139 °C. 1H NMR (CD3OD, 300 MHz): δ 0.94 (t,
6H, Sn-nBu), 1.3-1.6 (mc, 8H, Sn-nBu), 1.73 (t, 4H, Sn-nBu), 1.92
(s, 9H, 3- or 5-CH3), 2.03 (s, 6H, 3- or 5-CH3), 2.11 (s, 3H, 3- or
5-CH3), 2.35 (s, 9H, 4-CH3), 8.09 (s, 1H, CH). 119Sn NMR (CDCl3,
111.9 MHz): δ -271.0, -472.7. Cond. (CH2Cl2, concentration ) 0.97
× 10-3 M): Λ 18.9 Ω-1 cm2 mol-1. Cond. (acetone, concentration )
1.02 × 10-3 M): Λ 79.0 Ω-1 cm2 mol-1. MS (FAB-positive): m/z
587 ([{HC(3,4,5-Me3pz)3SnnBuCl2}]+, 100%, center of isotopic cluster).
MS (FAB-negative): m/z 317 ([SnnBuCl4]-, 60%, center of isotopic
cluster). Anal. Calcd for C27H46Cl6N6Sn2: C, 35.8; H, 5.1; N, 9.3.
Found: C, 36.1; H, 5.4; N, 9.5. IR (cm-1): 3132 w [ν(C-H)], 608 w
[ν(Sn-C)], 318 s [ν(Sn-Cl)].
1
analytical sample 16: mp (CH2Cl2, diethyl ether), 281 °C (dec.). H
NMR (CD3OD, 300 MHz): δ 6.44 (pt, 6H, 4-CH), 7.68, 7.74 (d, 12H,
3- and 5-CH), 8.69 (s, 2H, CH). Cond. (acetone, concentration ) 0.99
× 10-3 M): Λ 85.1 Ω-1 cm2 mol-1. MS (FAB-positive): m/z 573
([{HC(pz)3SnBr3}]+, 15%, center of isotopic cluster). MS (FAB-
negative): m/z 518 ([SnBr5]-, 35%, center of isotopic cluster), 359
([SnBr3]-, 100%, center of isotopic cluster). Anal. Calcd for C20H20-
Br12N12Sn3: C, 13.8; H, 1.2; N, 9.7. Found: C, 14.1; H, 1.3; N, 9.4.
IR (cm-1): 3107 w [ν(C-H)], 249 s [ν(Sn-Br)].
(q) [{HC(pz)3SnI3}+]2[{SnI6}2-]‚H2O, 17. To a stirred dichloro-
methane solution (10 mL) of HC(pz)3 (0.068 g, 0.320 mmol), at room
temperature and under nitrogen, SnI4 (0.310 g, 0.495 mmol) was added.
After 10 h, the brown precipitate formed was filtered off and washed
with diethyl ether to give (91% yield) the analytical sample 17: mp
(l) [{HC(3,4,5-Me3pz)3SnPhCl2}+][{SnPhCl4}-]‚H2O, 12. Com-
pound 12 (58% yield) was obtained similarly to compound 3: mp
(CH2Cl2, diethyl ether), 213-214 °C. 1H NMR (CD3OD, 300 MHz): δ
1.87, 1.93, 2.01, 2.67, 2.69, 2.79 (6 s, 27H, 3-, 4-, and 5-CH3), 2.36
(br, 2H, H2O), 7.30-7.60 (mc, 8H, SnPh), 7.80-7.95 (mc, 2H, SnPh),
8.28 (s, 1H, CH). 119Sn NMR (CDCl3, 111.9 MHz): δ -529.7. Cond.
1
(CH2Cl2, diethyl ether), 168-169 °C. H NMR (CD3OD, 300 MHz):
δ 1.30 (s, 2H, H2O), 6.44 (s br, 6H, 4-CH), 7.68, 7.75 (s br, 12H, 3-
and 5-CH), 8.70 (d, 2H, CH). Cond. (CH2Cl2, concentration ) 0.86 ×
10-3 M): Λ 0.76 Ω-1 cm2 mol-1. Cond. (acetone, concentration )
0.84 × 10-3 M): Λ 235.0 Ω-1 cm2 mol-1. Anal. Calcd for C20H22I12N12-
OSn3: C, 10.3; H, 1.0; N, 7.2. Found: C, 10.7; H, 1.0; N, 6.8. IR
(cm-1): 3124 w [ν(C-H)], 151 s [ν(Sn-I)], 3429 br [ν(H2O)].
(r) [{HC(4-Mepz)3SnCl3}+]2[{SnCl6}2-]‚H2O, 18. Compound 18
(66% yield) was obtained similarly to compound 15: mp (CH2Cl2,
diethyl ether), 239 °C (dec.). 1H NMR (CDCl3, 300 MHz): δ 2.21 (s,
(CH2Cl2, concentration ) 1.08 × 10-3 M): Λ 11.79 Ω-1 cm2 mol-1
.
Cond. (acetone, concentration ) 1.08 × 10-3 M): Λ 58.9 Ω-1 cm2
mol-1. MS (FAB-positive): m/z 607 ([{HC(3,4,5-Me3pz)3SnPhCl2}]+,
100%, center of isotopic cluster). MS (FAB-negative): m/z 337
([SnPhCl4]-, 20%, center of isotopic cluster). Anal. Calcd for C31H40-
Cl6N6Sn2O: C, 38.7; H, 4.2; N, 8.7. Found: C, 39.0; H, 4.5; N, 8.6.
IR (cm-1): 3124 w [ν(C-H)], 290 sh [ν(Sn-C)], 310 br [ν(Sn-Cl)],
454 m [ν(Ph)].
18H, 4-CH3), 2.30 (br, 2H, H2O), 8.05 (s, 6H, 3-CH, J(Sn-1H) )
3
(m) [{HC(3-Mepz)2(5-Mepz)SnMeCl2}+][{SnMeCl4}-], 13. Com-
pound 13 (53% yield) was obtained similarly to compound 1: mp
10.4 Hz), 9.05 (s, 6H, 5-CH), 10.08 (s, 2H, CH). 119Sn NMR (CDCl3,
111.9 MHz): δ -615.4. Cond. (CH2Cl2, concentration ) 0.90 × 10-3
M): Λ 0.16 Ω-1 cm2 mol-1. Cond. (acetone, concentration ) 0.98 ×
10-3 M): Λ 37.9 Ω-1 cm2 mol-1. Anal. Calcd for C26H34Cl12N12OSn3:
C, 23.8; H, 2.6; N, 12.8. Found: C, 23.4; H, 2.5; N, 12.3. IR (cm-1):
3097 w [ν(C-H)], 351 s [ν(Sn-Cl)], 3453 br [ν(H2O)].
1
(CH2Cl2, diethyl ether), 208 °C (dec.). H NMR (CDCl3, 300 MHz):
2
2
δ 1.67 (s, 3H, Sn-CH3, J(119Sn-1H) ) 117.7 Hz, J(117Sn-1H) )
112.5 Hz), 1.78 (s, 3H, Sn-CH3, 2J(119Sn-1H) ) 121.2 Hz, 2J(117Sn-
1H) ) 115.7 Hz), 2.63, 2.82, 2.91, 2.95 (4 s, 9H, 3- and 5-CH3), 6.39
(s, 3H, 4-CH), 8.33 (s, 1H, 3- or 5-CH), 8.99 (s, 2H, 3- or 5-CH),
10.00 (s, 1H, CH). 119Sn NMR (CDCl3, 111.9 MHz): δ -422.9,
-463.8. Cond. (CH2Cl2, concentration ) 1.03 × 10-3 M): Λ 0.83
Ω-1 cm2 mol-1. Cond. (acetone, concentration ) 0.98 × 10-3 M): Λ
34.1 Ω-1 cm2 mol-1. MS (FAB-positive): m/z 461 ([{HC(3-Mepz)2-
(5-Mepz)SnMeCl2}]+, 20%, center of isotopic cluster). MS (FAB-
negative): m/z 295 ([SnCl5]-, 20%, center of isotopic cluster), 225
([SnCl3]-, 20%, center of isotopic cluster). Anal. Calcd for C15H22-
Cl6N6Sn2: C, 24.5; H, 3.0; N, 11.4. Found: C, 25.0; H, 3.2; N, 11.4.
IR (cm-1): 3133 br, 3119 m [ν(C-H)], 533 w [ν(Sn-C)], 316 s [ν(Sn-
Cl)].
(s) [{HC(4-Mepz)3SnBr3}+]2[{SnBr6}2-], 19. Compound 19 (61%
yield) was obtained similarly to compound 16: mp (CH2Cl2, diethyl
ether), 263 °C (dec.). H NMR (CDCl3, 300 MHz): δ 2.23 (s, 18H,
1
4-CH3), 8.08 (s, 6H, 3-CH), 9.26 (s, 6H, 5-CH, 3J(Sn-1H) ) 12.2 Hz),
10.12 (s, 2H, CH). Cond. (CH2Cl2, concentration ) 1.01 × 10-3 M):
Λ 0.18 Ω-1 cm2 mol-1. Cond. (acetone, concentration ) 1.01 × 10-3
M): Λ 79.4 Ω-1 cm2 mol-1. Anal. Calcd for C26H32Br12N12Sn3: C,
17.1; H, 1.8; N, 9.2. Found: C, 16.8; H, 1.7; N, 8.9. IR (cm-1): 3065
w [ν(C-H)], 247 sh [ν(Sn-Br)].
(t) [{HC(4-Mepz)3SnI3}+]2[{SnI6}2-], 20. Compound 20 (25%
yield) was obtained similarly to compound 17: mp (CH2Cl2, diethyl
ether), 209 °C (dec.). H NMR (CDCl3, 300 MHz): δ 2.24 (s, 18H,
(n) [{HC(3-Mepz)2(5-Mepz)SnPhCl2}+]2[{SnPhCl5}2-]‚H2O, 14.
Compound 14 (70% yield) was obtained similarly to compound 3: mp
1

Sn(IV) Derivatives with Tris(pyrazol-1-yl)methanes
Inorganic Chemistry, Vol. 38, No. 25, 1999 5781
Table 1. Crystallographic Data and Details of Structure Refinements for Compounds 5, 7, and 25
5
7
25
formula
fw
cryst syst
space group
λ, Å
a/Å
b/Å
C38H59Cl9N12Sn3
1053.51
orthorhombic
P212121
0.710 73
12.476(4)
23.363(6)
23.540(6)
90
C18H28Cl6N6Sn2‚0.69CH2Cl2
873.05
monoclinic
P21/c
0.710 73
18.917(5)
9.888(3)
17.858(4)
110.75(3)
3123.7(14)
4
C19H28Br8N6Sn2‚0.86CH2Cl2
1290.17
monoclinic
P21/c
0.710 73
9.456(1)
26.452(5)
14.758(2)
92.17(2)
3688.8(9)
4
c/Å
â/deg
V/Å3
6861(3)
4
1.489
Z
d
calc/(g‚cm-3
)
1.780
22.50
2.324
101.66
µ/cm-1
15.88
cryst dimens/mm
type of diffractometer
T/K
0.3 × 0.3 × 0.3
STADI-4(Stoe)
293
22.2
8433
0.4 × 0.2 × 0.2
IPDS-4(Stoe)
190
23.3
17398
0.64 × 0.24 × 0.08
IPDS-4(Stoe)
190
26.2
29032
θmax/deg
reflns collected
reflns unique
7634
4349
7219
reflns with I > 2σ(I)
4230
5544/589
0.1704
0.0818
0.62/-0.48
3869
4349/328
0.1112
0.0452
0.95/-0.92
4632
6188/353
0.0815
0.0387
1.19/-1.08
data/params
wR2 (F2)a
R1b
largest peak and hole in ∆F/(e‚Å-3
)
a wR2 ) {Σ[w(Fo - Fc2)2]/Σ[w(Fo )2]}1/2
.
b R1 ) Σ||Fo| - |Fc||/|Fo|.
2
2
4-CH3), 8.09 (s, 6H, 3-CH, 3J(Sn-1H) ) 12.8 Hz), 8.68 (s, 6H, 5-CH),
10.36 (s, 2H, CH). Cond. (CH2Cl2, concentration ) 1.00 × 10-3 M):
Λ 2.34 Ω-1 cm2 mol-1. Cond. (acetone, concentration ) 0.85 × 10-3
M): Λ 247.0 Ω-1 cm2 mol-1. (FAB-negative): m/z 1270 ([I10]-, 20%,
center of isotopic cluster), 888 ([I7]-, 55%, center of isotopic cluster),
507 ([I4]-, 100%, center of isotopic cluster), 381 ([I3]-, 50%, center of
isotopic cluster). Anal. Calcd for C26H32I12N12Sn3: C, 13.1; H, 1.4; N,
7.0. Found: C, 13.6; H, 1.5; N, 6.9. IR (cm-1): 3166 w [ν(C-H)],
132 s [ν(Sn-I)].
(CH2Cl2, concentration ) 1.07 × 10-3 M): Λ 5.31 Ω-1 cm2 mol-1
.
Cond. (acetone, concentration ) 0.96 × 10-3 M): Λ 117.2 Ω-1 cm2
mol-1. MS (FAB-positive): m/z 565 ([{HC(3,4,5-Me3pz)3SnCl3}]+,
100%, center of isotopic cluster). MS (FAB-negative): m/z 295
([SnCl5]-, 100%, center of isotopic cluster). Anal. Calcd for C38H60-
Cl12N12O2Sn3: C, 30.5; H, 4.0; N, 11.2. Found: C, 30.7; H, 4.2; N,
10.9. IR (cm-1): 3036 w [ν(C-H)], 341 s [ν(Sn-Cl)], 3574 s [ν(H2O)].
(y) [{HC(3,4,5-Me3pz)3SnBr3}+][{SnBr5}-], 25. Compound 25
(97% yield) was obtained similarly to compound 16: mp (CH2Cl2,
1
(u) [{HC(3,5-Me2pz)3SnCl3}+]2[{SnCl6}2-]‚H2O, 21. Compound
21 (26% yield) was obtained similarly to compound 15: mp (CH2Cl2,
diethyl ether), 227 °C (dec.). H NMR (CDCl3, 300 MHz): δ 2.02,
2.45, 2.79, 2.82 (4 s, 27H, 3-, 4-, and 5-CH3), 8.24 (s, 1H, CH). Cond.
1
diethyl ether), 248 °C (dec.). H NMR (CD3OD, 300 MHz): δ 2.17
(CH2Cl2, concentration ) 1.20 × 10-3 M): Λ 16.13 Ω-1 cm2 mol-1
.
(br, 2H, H2O), 2.75 (s, 18H, 3- and 5-CH3), 2.77 (s, 18H, 3- and 5-CH3),
6.47 (s, 6H, 4-CH), 8.21 (s, 2H, CH). 119Sn NMR (CD3OD, 111.9
MHz): δ -577.1, -583.2. Cond. (CH2Cl2, concentration ) 0.92 ×
10-3 M): Λ 7.87 Ω-1 cm2 mol-1. Cond. (acetone, concentration )
0.74 × 10-3 M): Λ 58.1 Ω-1 cm2 mol-1. Anal. Calcd for C32H46Cl12N12-
OSn3: C, 27.5; H, 3.3; N, 12.0. Found: C, 27.7; H, 3.4; N, 11.9. IR
(cm-1): 3122 w [ν(C-H)], 344 s, 280 sh [ν(Sn-Cl)], 3483 br [ν(H2O)].
(v) [{HC(3,5-Me2pz)3SnBr3}+]2[{SnBr6}2-], 22. Compound 22
(98% yield) was obtained similarly to compound 16: mp (CH2Cl2,
diethyl ether), 242 °C (dec.). 1H NMR (CD3OD, 300 MHz): δ 2.75 (s,
18H, 3- or 5-CH3), 2.86 (s, 18H, 3- or 5-CH3), 6.44 (s, 6H, 4-CH),
8.20 (s, 2H, CH). Cond. (acetone, concentration ) 0.98 × 10-3 M):
Λ 90.9 Ω-1 cm2 mol-1. Anal. Calcd for C32H44Br12N12Sn3: C, 20.1;
H, 2.3; N, 8.8. Found: C, 19.7; H, 2.4; N, 8.3. IR (cm-1): 3086 w
[ν(C-H)], 237 s [ν(Sn-Br)].
Cond. (acetone, concentration ) 0.97 × 10-3 M): Λ 80.9 Ω-1 cm2
mol-1. MS (FAB-positive): m/z 699 ([{HC(3,4,5-Me3pz)3SnBr3}]+,
100%, center of isotopic cluster). MS (FAB-negative): m/z 519
([SnBr5]-, 100%, center of isotopic cluster), 438 ([SnBr4]-, 60%, center
of isotopic cluster), 359 ([SnBr3]-, 100%, center of isotopic cluster).
Anal. Calcd for C19H28Br8N6Sn2: C, 18.5; H, 2.4; N, 6.8. Found: C,
18.4; H, 2.4; N, 6.5. IR (cm-1): 3089 w [ν(C-H)], 246 br [ν(Sn-
Br)].
(z) [{HC(3-Mepz)2(5-Mepz)SnCl3}+]2[{SnCl6}2-]‚2H2O, 26. Com-
pound 26 (47% yield) was obtained similarly to 15: mp (CH2Cl2,
1
diethyl ether), 248 °C (dec.). H NMR (CD3OD, 300 MHz): δ 2.20
(br, 4H, H2O), 2.46, 2.80, 3.10 (3 s, 18H, 3- and 5-CH3), 6.46, 6.50 (2
s br, 6H, 4-CH), 7.27 8.24, 9.35, 9.52 (4 s, 6H, 3- and 5-CH), 11.3 (br,
2H, CH). 119Sn NMR (CDCl3, 111.9 MHz): δ -629.1. Cond. (CH2Cl2,
concentration ) 0.99 × 10-3 M): Λ 0.37 Ω-1 cm2 mol-1. Cond.
(acetone, concentration ) 1.00 × 10-3 M): Λ 113.7 Ω-1 cm2 mol-1
.
(w) [{HC(3,5-Me2pz)3SnI3}+]2[{SnI6}2-]‚H2O, 23. Compound 23
(57% yield) was obtained similarly to compound 17: mp (CH2Cl2,
Anal. Calcd for C26H36Cl12N12O2Sn3: C, 23.5; H, 2.7; N, 12.6. Found:
C, 23.0; H, 2.7; N, 12.2. IR (cm-1): 3103 br [ν(C-H)], 341 s [ν(Sn-
Cl)], 3454 br [ν(H2O)].
1
diethyl ether), 166-167 °C. H NMR (CDCl3, 300 MHz): δ 2.05 (s,
18H, 3- or 5-CH3), 2.18 (s, 18H, 3- or 5-CH3), 2.42 (br, 2H, H2O),
7.26 (s, 6H, 4-CH), 8.09 (s, 2H, CH). Cond. (CH2Cl2, concentration )
0.80 × 10-3 M): Λ 48.6 Ω-1 cm2 mol-1. MS (FAB-negative): m/z
1270 ([I10]-, 30%, center of isotopic cluster), 888 ([I7]-, 60%, center
of isotopic cluster), 507 ([I4]-, 100%, center of isotopic cluster). Anal.
Calcd for C32H46I12N12OSn3: C, 15.4; H, 1.9; N, 6.7. Found: C, 15.6;
H, 1.8; N, 6.5. IR (cm-1): 3078 w [ν(C-H)], 159 m [ν(Sn-I)], 3565
br [ν(H2O)].
(aa) [{HC(3-Mepz)2(5-Mepz)SnBr3}+]2[{SnBr6}2-], 27. Compound
27 (35% yield) was obtained similarly to 16: mp (CH2Cl2, diethyl
ether), 141-142 °C. 1H NMR (CDCl3, 300 MHz): δ 2.47, 2.51, 2.89,
3.10 (4 s, 18H, 3- and 5-CH3), 6.45 (br, 6H, 4-CH), 8.33, 9.31 (2 s br,
6H, 3- and 5-CH), 9.89 (s, 2H, CH). Cond. (CH2Cl2, concentration )
0.46 × 10-3 M): Λ 2.46 Ω-1 cm2 mol-1. Cond. (acetone, concentration
) 0.48 × 10-3 M): Λ 76.5 Ω-1 cm2 mol-1. Anal. Calcd for C26H32-
Br12N12Sn3: C, 17.1; H, 1.8; N, 9.2. Found: C, 16.7; H, 1.8; N, 8.9.
IR (cm-1): 3104 m [ν(C-H)], 237 s [ν(Sn-Br)].
(x) [{HC(3,4,5-Me3pz)3SnCl3}+]2[{SnCl6}2-]‚2H2O, 24. Compound
24 (78% yield) was obtained similarly to compound 15: mp (CH2Cl2,
diethyl ether), 227-228 °C. 1H NMR (CD3OD, 300 MHz): δ 2.03 (s,
18H, 3-, 4-, or 5-CH3), 2.36 (br, 4H, H2O), 2.67 (s, 18H, 3-, 4-, or
5-CH3), 2.69 (s, 18H, 3-, 4-, or 5-CH3), 8.26 (s, 2H, CH). Cond.
X-ray Diffraction Studies. The details of crystal data collection
and refinement for complexes 5, 7, and 25, collected at low temperatures
on an IPDS (Stoe) diffractometer, are given in Table 1. Graphite-

5782 Inorganic Chemistry, Vol. 38, No. 25, 1999
Pettinari et al.
Table 2. Selected Bond Distances (Å) and Angles (deg) for Compounds 5, 7, and 25
5
7
25
Sn(1)-C(14)
Sn(1)-N(1)
Sn(1)-N(3)
Sn(1)-N(5)
Sn(1)-Cl(1)
Sn(1)-Cl(2)
Sn(2)-C(31)
Sn(2)-N(7)
Sn(2)-N(9)
Sn(2)-N(11)
Sn(2)-Cl(3)
Sn(2)-Cl(4)
Sn(3)-C(35)
Sn(3)-Cl(5)
Sn(3)-Cl(6)
Sn(3)-Cl(7)
Sn(3)-Cl(8)
Sn(3)-Cl(9)
2.17(2)
2.30(2)
2.27(2)
2.33(2)
2.379(8)
2.406(7)
2.26(2)
2.22(2)
2.32(2)
2.23(2)
2.393(9)
2.35(1)
2.21(2)
2.466(6)
2.483(6)
2.510(6)
2.503(6)
2.499(6)
Sn(1)-C(1)
Sn(1)-N(1)
Sn(1)-N(3)
Sn(1)-N(5)
Sn(1)-Cl(1)
Sn(1)-Cl(2)
Sn(2)-C(18)
Sn(2)-Cl(3)
Sn(2)-Cl(4)
Sn(2)-Cl(5)
Sn(2)-Cl(6)
2.214(5)
2.259(6)
2.310(5)
2.282(5)
2.387(2)
2.372(2)
2.167(6)
2.486(2)
2.455(2)
2.349(2)
2.319(2)
Sn(1)-Br(1)
Sn(1)-Br(2)
Sn(1)-Br(3)
Sn(1)-Br(4)
Sn(1)-Br(5)
2.4823(8)
2.5598(9)
2.5616(9)
2.505(1)
2.5108(8)
Sn(2)-N(1)
Sn(2)-N(1)
Sn(2)-N(5)
Sn(2)-Br(6)
Sn(2)-Br(7)
Sn(2)-Br(8)
2.234(5)
2.225(5)
2.242(4)
2.5057(9)
2.5128(9)
2.5185(10)
C(14)-Sn(1)-N(3)
N(3)-Sn(1)-N(5)
N(3)-Sn(1)-Cl(2)
Cl(1)-Sn(1)-Cl(2)
Cl(14)-Sn(1)-Cl(1)
Cl(6)-Sn(3)-Cl(8)
166.7(9)
75.8(7)
85.4(5)
98.6(3)
103.1(7)
171.6(3)
N(1)-Sn(1)-N(3)
77.7(2)
87.7(2)
92.3(2)
100.3(2)
99.51(8)
118.09(7)
N(1)-Sn(2)-N(3)
N(1)-Sn(2)-N(5)
N(3)-Sn(2)-N(5)
N(1)-Sn(2)-Br(7)
Br(6)-Sn(2)-Br(7)
Br(2)-Sn(1)-Br(3)
80.6(2)
79.4(2)
79.9(2)
90.61(12)
97.40(3)
174.84(3)
N(1)-Sn(1)-Cl(2)
C(1)-Sn(1)-N(5)
C(1)-Sn(1)-Cl(2)
Cl(1)-Sn(1)-Cl(2)
Cl(5)-Sn(2)-Cl(6)
Scheme 1
monochromated Mo KR radiation was used for the measurements. The
lattice parameters of compound 5 were optimized from a least-squares
calculation on 24 carefully centered reflections at 16-18° (θ). The
lattice parameters of both 7 and 25 were calculated from positions of
5000 scanned reflections in the range 3-24° (θ). No absorption
correction was applied for 5 and 7. A numerical absorption correction
was applied for 25 after crystal shape optimization using X-SHAPE
(Stoe).
Structure solutions and refinements were carried out by using
SHELXS-9713 and SHELXL-9314 programs. Non-hydrogen atoms were
refined anisotropically by full-matrix least-squares techniques based
on F2. Hydrogen atoms were placed at the calculated positions and
were included in the final refinements in a riding mode. Occupancies
of the solvated CH2Cl2 molecules in the structures of 7 and 25 were
refined to 0.689(9) and 0.860(9), respectively. Selected bond lengths
and angles for 5, 7, and 25 are listed in Table 2.
Me2pz)3, and HC(3,4,5-Me3pz)3 with R2SnCl2 acceptors (R )
Me, nBu, or Ph) in diethyl ether or CH2Cl2 solution, no products
were obtained, even if the reaction was carried out under forcing
conditions (i.e. strong excess of the donor and refluxing solvent).
When this reaction was carried out in n-hexane (suspension),
an oil was obtained which seemed to be a mixture of the starting
reagents, without evidence of any bonding interaction. In fact,
the IR and NMR spectra of the oil obtained are almost identical
to those found for the free ligand and the organotin(IV) acceptor.
On the other hand the interaction between monoorganotin(IV)
n
acceptors RSnCl3 (R ) Me, Bu, or Ph) and HC(pz)3, HC(4-
Mepz)3, HC(3,5-Me2pz)3, HC(3,4,5-Me3pz)3, or HC(3-Mepz)2-
(5-Mepz) in diethyl ether resulted in compounds 1-14 (Schemes
1-3) independently of the reaction conditions and acceptor:
ligand ratio employed. The analytical and spectral data of
complexes 1-14 are listed in the Experimental Section. The
stoichiometries of compounds 1-14 differ from those reported
in the literature for other poly(pyrazol-1-yl)alkane-organo-
tin(IV) derivatives:7-10 the tris(pyrazol-1-yl)methane ligands are
potentially tridentate and usually tend to bind a metal as
tridentates, the presence of only two free coordination sites on
the RSnCl3 acceptor in this case inducing a charge separation,
Results and Discussion
Syntheses and Properties. From the interaction of the tris-
(pyrazol-1-yl)methane donors HC(pz)3, HC(4-Mepz)3, HC(3,5-
(13) Sheldrick, G. M. SHELXL-93. Program for crystal structure refine-
ment; University of Go¨ttingen: Go¨ttingen, Germany, 1993.
(14) Sheldrick, G. M. SHELXS-97. Program for crystal structure refine-
ment; University of Go¨ttingen: Go¨ttingen, Germany, 1997.

Sn(IV) Derivatives with Tris(pyrazol-1-yl)methanes
Inorganic Chemistry, Vol. 38, No. 25, 1999 5783
Scheme 2
Scheme 3
with formation of 1:1 or 2:1 ionic complexes in the solid state.
The presence of methyl groups in the 3,5-positions of the azole
rings influences the stoichiometry of products 1-14, the ligands
HC(pz)3 and HC(4-Mepz)3, without any substituent in the 3-
and 5-positions, yielding, independently of the nature of the
acceptor and of the reaction conditions, the 2:1 ionic derivatives
1-6 with general formula [{LSnRCl2}+]2[{SnRCl5}2-] as
shown in Scheme 1, whereas the interaction of the ligands
HC(3,5-Me2pz)3 and HC(3,4,5-Me3pz)3 with RSnX3 acceptors
gave ionic compounds 7-12 [{LSnRCl2}+][{SnRCl4}-] with
1:1 stoichiometry (Scheme 2).
To demonstrate that the steric effects of Me groups in a
position near the coordination site influence the stoichiometry
of the final product, we synthesized a new tridentate ligand,
HC(3-Mepz)2(5-Mepz), according to literature procedures.11
From the interaction of HC(3-Mepz)2(5-Mepz) with RSnCl3 (R
) Me or Ph), the adducts [{LSnMeCl2}+][{SnMeCl4}-] (13)
and [{LSnPhCl2}+]2[{SnPhCl5}2-] (14) were isolated, inde-
pendently of the acceptor:ligand ratio used (Scheme 3); no
adduct was obtained under the same conditions when nBuSnCl3
as acceptor was employed.
From the interaction of HC(pz)3, HC(4-Mepz)3, HC(3,5-
Me2pz)3, HC(3,4,5-Me3pz)3, or HC(3-Mepz)2(5-Mepz) with the
tetrahalidetin(IV) acceptors SnX4 (X ) Cl, Br, or I), in CH2Cl2
solution, in nitrogen atmosphere, at -40 °C, adducts 15-27
were obtained (Schemes 4 and 5). Independently of the nature
of the acceptor and from these reaction conditions the 2:1 ionic
adducts [{LSnX3}+]2[{SnX6}2-] were isolated for HC(pz)3,
HC(3,5-Me2pz)3, HC(4-Mepz)3, or HC(3-Mepz)2(5-Mepz) ligands
(Scheme 4). The only exception is represented by the ligand
HC(3,4,5-Me3pz)3, which gives the 2:1 adduct [{LSnCl3}+]2[{Sn-
Cl6}2-] (24) for X ) Cl and the 1:1 adduct [{LSnBr3}+][{Sn-
Br5}-] (25) for X ) Br (Scheme 5). It is interesting to note
that no derivative was afforded from the interaction of HC-

5784 Inorganic Chemistry, Vol. 38, No. 25, 1999
Pettinari et al.
Scheme 4
Scheme 5
(3,4,5-Me3pz)3 and HC(3-Mepz)2(5-Mepz) with SnI4 under the
conditions indicated in the Experimental Section.
All of these tin(IV) and organotin(IV) complexes at room
temperature are colorless solids, very soluble in chlorinated

Sn(IV) Derivatives with Tris(pyrazol-1-yl)methanes
Inorganic Chemistry, Vol. 38, No. 25, 1999 5785
Figure 2. PLUTO representation of the molecular structure of complex
5.
Figure 3. PLUTO representation of the molecular structure of complex
7.
solvents and acetone. They can be handled in air for a short
time without any significant decomposition. However, prolonged
storage in air at room temperature or in solutions leads to slow
decomposition.
The conductivity measurements (see Experimental Section)
indicated that among the HC(pz)3 and HC(4-Mepz)3 derivatives,
only [{HC(pz)3SnI3}+]2[{SnI6}2-]‚H2O and [{HC(4-Mepz)3-
SnI3}+]2[{SnI6}2-] are electrolytes in CH2Cl2 and acetone. A
similar behavior has been previously observed for analogous
organotin(IV) complexes containing N-donor ligands: generally,
the chloro and bromo derivatives are not electrolytes in CH2Cl2
and acetone, whereas the corresponding iodo derivatives exhibit
in the same solutions a conductivity typical of a strong
electrolyte.10,15 The derivatives of HC(3,5-Me2pz)3CH are partly
ionized in CH2Cl2 and acetone solutions. The complexes of
HC(3,4,5-Me3pz)3CH, the most basic and the most sterically
hindered ligand, exhibit a value of conductivity in CH2Cl2 and
acetone typical of a 1:1 electrolyte. Finally, the derivatives of
HC(3-Mepz)2(5-Mepz) are nonelectrolytes in CH2Cl2, whereas
they are partly ionized in acetone. The vaporimetric molecular
weight determinations, carried out only for sufficiently soluble
and stable compounds, gave values always greater than those
expected for the ionic 1:1 and 2:1 formulas, in accordance with
formation of ion-pairing compounds, as resulted from the
conductivity data.
The tin(IV) derivatives 1-3 and 15-17 are generally less
soluble and more dissociated in chloroform solution with respect
to all the other derivatives containing a methyl-substituted
ligand. The total or partial lack of conductivity observed in 1-9,
11-16, 18-19, 21, 25, and 27 can be attributed to ion-pair
couple formation or else to dissociation of the Sn-N bond and
re-formation of the starting reagents, as is clear from NMR data.
Solid State Structures of [{HC(4-Me2pz)3SnnBuCl2}+]2-
[{SnnBuCl5}2-] (5), [{HC(3,5-Me2pz)3SnMeCl2}+][{SnMe-
Cl4}-] (7), and [{HC(3,4,5-Me3pz)3SnBr3}+][{SnBr5}-] (25).
Diagrams of the cations and anions in 5, 7, and 25 are provided
in Figures 2-4. All three compounds are ionic: in the cation,
the tin atom is always situated in a pseudooctahedral environ-
ment coordinated by a tridentate tris(pyrazol-1-yl)methane, an
alkyl and two chloride groups (5 and 7), or a tridentate tris-
(pyrazol-1-yl)methane and three bromine atoms (25). The Sn-N
Figure 4. PLUTO representation of the molecular structure of complex
25.
distances, lying in the range 2.22-2.33 Å, are not greatly
influenced by the nature of the other ligands in the coordination
environment of the tin. Nevertheless, as previously observed
also in poly(pyrazol-1-yl)borate-monoorganotin(IV) deriva-
tives,2 those Sn-N bonds trans to carbon atoms are slightly
shorter than those trans to halides. In derivative 25, with three
bromine atoms in trans positions, there is practically no
difference in Sn-N and, as a consequence of the small tripod
ligand “bite”, all N-Sn-N angles are appreciably less than 90°.
Similar Sn-N bond distances have been found in complexes
containing an anionic tris(pyrazolyl)borate ligand [Sn{HB(3,4,5-
Me3pz)3MeCl2] (Sn-N ) 2.24-2.25 Å).2d By contrast, the Sn-
C, Sn-N, and Sn-Cl distances are all markedly different from
those found in the cation of [{(2,2′,2′′-terpyridyl)SnMe2Cl}+]-
[{SnMe2Cl3}-],16 presumably due to the lower Lewis acidity
of the [SnR2Cl]+ moiety with respect to that of the [SnRCl2]+
acceptor. In the crystal structures of [H2C(4-Mepz)2Me2SnCl2] 10
and [H2C(3,5-Me2pz)2Ph2SnCl2] 17 the Sn-N bond distances are
substantially longer (in the range of 2.40-2.50 Å) because of
the electroneutrality of this type of compound.
In the anionic components of these complexes, the tin is five-
coordinate (trigonal-bipyramidal) in 7 and 25 and six-coordinate
(octahedral) in derivative 5. In 7, the axial distances Sn-Cl
(2.46, 2.49 Å) are longer than equatorial ones (2.32-2.35 Å).
These values can be compared to those found in [{AsPh4}+]-
[{SnMeCl4}-]: Sn-Cl (axial), 2.49 Å; Sn-Cl (equatorial), 2.27
Å.18 The Sn-C bond distances are also similar: 2.15 Å in 7
and 2.17 Å in [{AsPh4}+][{SnMeCl4}-].18 As observed in other
examples of trigonal-bipyramidal structures with two different
ligand types coordinated to a tin(IV) center, the more elec-
(15) (a) Pettinari, C.; Marchetti, F.; Cingolani, A.; Bartolini, S. Polyhedron,
1996, 8, 1263. (b) Pettinari, C.; Marchetti, F.; Pellei, M.; Cingolani,
A.; Barba, L.; Cassetta, A. J. Organomet. Chem. 1996, 515, 119. (c)
Pettinari, C.; Pellei, M.; Miliani, M.; Cingolani, A.; Cassetta, A.; Barba,
L.; Pifferi, A.; Rivarola, E. J. Organomet. Chem. 1998, 553, 345. (d)
Holecek, J.; Licka, A. Inorg. Chim. Acta 1986, 118, L15. (e) Lockhart,
T. P.; Manders, W. F. J. Am. Chem. Soc. 1987, 109, 7015. (f) Lockhart,
T. P.; Manders, W. F. J. Am. Chem. Soc. 1986, 108, 892.
(16) Einstein, F. W. B.; Penfold, B. R. J. Chem. Soc. A 1969, 3019.
(17) Cox, J. M.; Rainone, S.; Siasios, G.; Tiekink, E. R. T.; Webster, L.
K. Main Group Met. Chem. 1995, 18, 93.
(18) Webster, M.; Mudd, K. R.; Taylor, D. J. Inorg. Chim. Acta 1976, 20,
231.

5786 Inorganic Chemistry, Vol. 38, No. 25, 1999
Pettinari et al.
tronegative ligands (Cl in our case) are linked preferentially in
the axial positions.19 In 25, the distribution of the axial and
equatorial bonds is also similar: Sn-Br (axial) 2.56 Å, Sn-Br
(equatorial) 2.48-2.51 Å. As expected, the Sn-Br distances
a strengthening of the Sn-Cl bond and then a weakening of
the Sn-N bond.
The 1H NMR spectra of derivatives 1-6 contain signals not
only due to the complex but also attributed to the uncoordinated
ligand; the dissociation is minimal in chloroform and greater
in acetone solutions. Near the signals of the free ligand, it is
always possible to detect at least two different absorptions for
each pyrazole proton, and one absorption for the bridged CH
group. This excludes the existence of different isomers in
solution, indicative of inequivalence of the three pyrazole rings,
in accordance with the solid-state data. The tin-proton coupling
constants are different from those observed for the starting
organotin(IV) derivatives,30 being of the same order of magni-
tude as those observed in six-coordinated tin(IV) complexes.15
The 1H NMR spectra of 1-6 exhibit also two different sets of
signals for the alkyl and the aryl groups linked to the tin, in
accordance with the presence of two different organotin(IV)
centers. In the 119Sn NMR spectra of 1-6 a signal typical of
six-coordinated organotin(IV) derivatives only was found.
The spectra of 7-12 exhibit at least two different groups of
signals for each heterocyclic proton and one signal for the
bridged C-H group, suggesting an inequivalence of the three
pyrazole rings in accordance with the solid-state structure, the
downfield shifts clearly indicating the existence of complexes
7-12 in solution. The tin-proton coupling constants are
different from those observed for the starting organotin(IV)
derivatives and of the same order of magnitude as those
observed in six- or five-coordinated tin(IV) complexes.10,15,30
The 119Sn NMR spectra of 7-12 are in accordance with the
solid-state structure: in CDCl3 solution, two signals, typical of
a five- and six-coordinate tin(IV) site, respectively, were
generally found.
in [{SnBr5}-] are shorter than in octahedral [{SnBr6}2-
]
compounds such as, for example, in [{Me2NH2}+]2[{SnBr6}2-
]
(2.60 Å).20 In the anion of 5 [{SnnBuCl5}2-], the tin is
octahedrally coordinated with the shorter Sn-Cl distance (2.43
Å) situated trans to the Sn-C bond (2.21 Å). The other four
Sn-Cl distances are in the range 2.48-2.51 Å. It is worth noting
that, due to the increase of tin coordination number, the Sn-Cl
equatorial distances in [{SnnBuCl5}2-] are very close to the
equatorial Sn-Br distances in [{SnBr5}-]. Similar relationships
between the Sn-Cl and Sn-C distances in octahedral anions
21
[{SnRCl5}2-] can be found in [{SnPhCl5}2-
[{SnEtCl5}2-].22
]
and in
Another interesting feature is that, in the cations of com-
pounds 5, 7, and 25, there is very little torsion of the pyrazolyl
rings with respect to the C3V axis of the molecule; the Sn-N-
N-C torsion angles of the pyrazolyl rings average 2.2°, 4.8°,
and 3.4° for 5, 7, and 25, respectively. The lack of twist contrasts
with recent results on Tl23 and Cd24 complexes but is in good
agreement with the data on Ag25 and Cu26 complexes. Appar-
ently in these tris(pyrazol-1-yl)methane-tin(IV) complexes, no
distortion of the ligand is required, the size of tin(IV) matching
the bite of the ligand.
Spectroscopy. The most important IR data of the free donors
and their corresponding tin(IV) complexes are listed in the
Experimental Section. The ligand absorptions are not markedly
shifted upon coordination to tin(IV), suggesting a weak influence
of the complexation on the absorptions within the donor. The
Sn-C27 and Sn-Cl28 stretching vibrations agree well with the
trends previously observed in similar complexes containing
N-donor chelating ligands.10,29 In compounds 15, 18, 21, 24,
and 26, the Sn-Cl stretching frequencies are shifted to higher
fields with respect to those reported in tri- and tetrachlorotin(IV)
derivatives; an increase of the stretching frequencies suggests
In the spectra of the SnX4 derivatives 15-27, the ∆ values
(∆ ) difference in chemical shift for the same type of proton
in the free base and in its tin(IV) complex) are strongly
dependent on the nature of the N3-donor, on the halide, and on
the structure of the complex.
The derivatives 15-17 are partially dissociated in solution.
In the spectra of complexes 24 and 25 the ∆ values of the
methyls of the pyrazole ring are indeterminate, due to uncer-
tainty in the assignment of the signals, whereas ∆ for the
bridging C-H proton is in the range 0.19-0.21 ppm.
The ∆ values for the derivatives 18-20 prove the existence
of the complexes in solution, these ∆ values being larger than
those observed in all the other derivatives, in accordance with
a stronger Sn-N bonding interaction and perhaps with a greater
stability in solution. Moreover, the derivatives 18-20 are more
soluble than the other complexes, so that it has been possible
to detect the H-3 satellite peaks due to the tin-proton coupling
constants that are typical of undissociated six-coordinate or-
ganotin(IV) complexes in solution.28,30
The structures of complexes containing tris(pyrazol-1-yl)-
borates2 and tris(pyrazol-1-yl)methanes are presumably similar,
the tripodal arrangement of the pyrazole rings being the
dominant controlling factor. The difference in the charge
between the two types of ligands produces only small effects
on the structure of related complexes, not only in the solid state
but also in solution, as demonstrated by the very close values
of the 119Sn chemical shift: the δ(119Sn) of 1 and 4 (-448 and
(19) Muetterties, E. L.; Mahler, W.; Packer, K. J.; Schmultzer, R. Inorg.
Chem. 1964, 3, 1298.
(20) Dilton, K. B.; Halfpenny, J.; Marshall, A. J. Chem. Soc., Dalton Trans.
1983, 1091.
(21) Storck, P.; Weiss, A. Acta Crystallogr. C 1990, 46, 767.
(22) Paseshnitchenko, K. A.; Aslanov, L. A.; Jatsenko, A. V.; Medvedev,
S. V. J. Organomet. Chem. 1985, 267, 187.
(23) Reger, D. L.; Collins, J. E.; Layland, R.; Adams, R. D. Inorg. Chem.
1996, 35, 1372.
(24) Reger, D. L.; Collins, J. E.; Myers, S. M.; Liable-Sands, L. M.;
Rheingold, A. L. Inorg. Chem. 1996, 35, 4904.
(25) Rasika Dias, H. V.; Wang, Z.; Jin, W. Inorg. Chem. 1997, 36, 6205.
(26) Reger, D. L.; Collins, J. E.; Rheingold, A. L.; Liable-Sands, L. M.
Organometallics 1996, 15, 2029.
(27) (a) Clark, J. P.; Wilkins, C. J. J. Chem. Soc. A 1966, 871. (b) Clark,
R. J. H.; Davies A. G.; Puddephatt, R. J. J. Chem. Soc. A 1968, 1828.
(c) Edgell, W. F.; Ward, W. H. J. Mol. Spectrosc. 1962, 8, 343. (d)
Sandhu, J. K.; Kaur, G.; May, J. R.; McWhinnie, W. R.; Poller, R. C.
Spectrochim. Acta A 1971, 27, 969. (e) Smith, A. L. Spectrochim.
Acta A 1968, 24, 695. (f) Dance, M. S.; McWhinnie, W. R.; Poller,
R. C. J. Chem. Soc., Dalton Trans. 1976, 2349. Poller, R. C. The
Chemistry of Organotin Compounds; Logos: London, 1970. (g)
Newman, W. P. The Organic Chemistry of Tin; Wiley: New York,
1970. (h) Ho, B. W. K.; Zuckerman, J. J. Inorg. Chem., 1973, 12,
1552.
(28) (a) Alleston, D. L.; Davies, A. G. J. Chem. Soc. 1961, 2050. (b)
Ohkaku, N.; Nakamoto, K. Inorg. Chem. 1973, 12, 2440. (c) de Sousa,
G. F.; Filgueiras, C. A. L.; Darensbourg, M. Y.; Reibenspies, J. H.
Inorg. Chem. 1992, 31, 3044. (d) Caruso, F.; Giomini, M.; Giuliani
A. M.; Rivarola, E. J. Organomet. Chem. 1996, 506, 67.
(29) (a) Harrison, P. G.; King, T. J.; Richards, J. A. J. Chem. Soc., Dalton
Trans. 1974, 1723. (b) Lopez, C.; Sanchez Gonzales, A.; Garcia, M.
E.; Casas, J. S.; Sordo J.; Graziani, R.; Casellato, U. J. Organomet.
Chem. 1992, 434, 261.
(30) (a) Wrackmeyer, B. Annu. Rep. NMR Spectrosc. 1985, 16, 73. (b)
Harris, R. K.; Sebald, A.; Furlani, D.; Tagliarini, G. Organometallics
1988, 7, 388. (c) Kennedy, J. D.; McFarlane, W. Silicon, Germanium,
Tin and Lead. In Multinuclear NMR; Mason, J., Ed.; Plenum Press:
New York, 1987; pp 305-333.

Sn(IV) Derivatives with Tris(pyrazol-1-yl)methanes
Inorganic Chemistry, Vol. 38, No. 25, 1999 5787
-455 ppm, respectively) and those of the isoelectronic [MeSnCl2-
{HB(pz)3}] 2b and [MeSnCl2{HB(4-Mepz)3}] 2a (-478 and
-486 ppm, respectively) clearly indicate that the bonding is
dominated by the σ-donating ability of the ligand.
In conclusion both 1:1 and 2:1 ionic tin(IV) and organotin(IV)
compounds can be synthesized by modifying the steric properties
of the tris(pyrazol-1-yl)methane ligands: for example, the
donors having a Me in a position near the coordination site allow
the preparation of 2:1 [{LSnRCl2}+]2[{SnRCl5}2-] or [{LSn-
X3}+]2[{SnX6}2-], whereas those without Me in the 3 position
allow the 1:1 [{LSnRCl2}+][{SnRCl4}-] or [{LSnX3}+][{SnX5}-]
species to be obtained. To date it has not proven possible to
prepare new tin(IV) complexes containing a tridentate tris-
(pyrazol-1-yl)methane and two organic groups linked to a tin
center. Studies are in progress to evaluate the coordinating ability
of tris(pyrazol-1-yl)methane ligands toward tin(IV) and orga-
notin(IV) centers containing different counterions.
Positive and negative fast atom bombardment (FAB) mass
spectrometric data for the tin and organotin(IV) complexes 1-3,
10-13, 16, 20, and 23-25 are reported in the Experimental
Section. The fragment ions containing tin(IV) and halide atoms
are identified by the presence of the characteristic clusters of
isotopic peaks, corresponding to the relative abundance of tin
and halide isotopes. In the FAB-MS analysis of our tin(IV)
complexes, the intact cation and anion are often the major
fragment ions, and with the exception of the protonated ligand
molecule the other diagnostic fragments are generally very poor.
In some cases in the high-mass region of the ligands and their
complexes there are also a few characteristic peaks due to
interaction with the m-nitrobenzyl alcohol matrix.
Acknowledgment. We are grateful to the “CARIMA
Foundation”, the University of Camerino, and the Consiglio
Nazionale delle Ricerche (CNRsRome) for financial support.
The initial fragmentation pathway of the tin(IV) halide anions
[{SnX5}-] and [{RSnX4}-] generally consists of sequential loss
of the radicals X and R. In the negative-FAB spectra of
[{LSnRCl2}+]2[{SnRCl5}2-] and [{LSnX3}+]2[{SnX6}2-] com-
Supporting Information Available: Three X-ray crystallographic
files, in CIF format. This material is available free of charge via the
Internet at http://pubs.acs.org.
plexes, no peak attributable to the intact dianions [{SnRCl5}2-
]
or [{SnX6}2-] is present: the most important fragment ions are
those obtained by the subtraction of one halide or one R radical
from these ionic species.
IC9906252