Intramolecular chalcogen - Tin interactions in [(o-MeEC6H 4)CH2]2SnPh2-nCln (E = S, O, CH2; n = 0, 1, 2) and intermodular chlorine - Tin interactions in the meta- and para-methoxy isomers

Article abstract of DOI:10.1021/ic901800c

Organotin(IV) compounds of the type [(o-MeEC₆H ₄)CH₂]₂SnPh_2-nCl_n were synthesized, E = O, n = 0 (1), n = 1 (2), and n = 2 (3); E = S, n = 0 (4), n = 1 (5), and n = 2 (6); and E = CH₂, D = O (7), n = 1 (8), and n = 2 (9). The dichloro compounds 3 and 6 have been investigated by single-crystal X-ray diffraction and exhibit bicapped tetrahedral geometry at the tin atom as a consequence of significant intramolecular Sn ... -O (3) and Sn ... S (6) secondary bonding, in monomolecular units. Compound 3, when crystallized from a hexane/THF solvent mixture, shows two different conformers, 3' and 3", in the crystal structure; 3' has two equivalent Sn ... O interactions, while 3" has two nonequivalent Sn ... O interactions. Upon the recrystallization of 3 from hexane, only a single structural form is observed, 3'. The Sn ... E distances in 3', 3", and 6 are 71.3, 73.5 and 72.9, and 76.3% of the ΣvdW radii, respectively. The meta- and para-substituted isomers of 3 (10,.11) exhibit a distortion at the tin atom due to selfassociation via intermolecular Sn ...Cl interactions, resulting in polymeric structures. ¹¹⁹Sn NMR spectroscopy suggests that the intramolecular Sn ... E interactions persist in solution for the dichloride compounds 3 and 6.

Full text of DOI:10.1021/ic901800c

960 Inorg. Chem. 2010, 49, 960–968
DOI: 10.1021/ic901800c
Intramolecular Chalcogen-Tin Interactions in [(o-MeEC6H4)CH2]2SnPh2-nCln
(E = S, O, CH2; n = 0, 1, 2) and Intermolecular Chlorine-Tin Interactions in the
meta- and para-Methoxy Isomers
Diana Gabriela Vargas-Pineda, Tanya Guardado, Francisco Cervantes-Lee,† Alejandro J. Metta-Magana, and
Keith H. Pannell*
Department of Chemistry, University of Texas at El Paso, El Paso, Texas 79968-0513. †Dr. Francisco (Paco)
ꢀ
Jose Cervantes-Lee: 11/21/1950-2/15/2007
Received September 14, 2009
Organotin(IV) compounds of the type [(o-MeEC6H4)CH2]2SnPh2-nCln were synthesized, E = O, n = 0 (1), n = 1 (2),
and n = 2 (3); E = S, n = 0 (4), n = 1 (5), and n = 2 (6); and E = CH2, n = 0 (7), n = 1 (8), and n = 2 (9). The dichloro
compounds 3 and 6 have been investigated by single-crystal X-ray diffraction and exhibit bicapped tetrahedral
geometry at the tin atom as a consequence of significant intramolecular Sn O (3) and Sn S (6) secondary
3 3 3
3 3 3
bonding, in monomolecular units. Compound 3, when crystallized from a hexane/THF solvent mixture, shows two
different conformers, 30 and 300, in the crystal structure; 30 has two equivalent Sn O interactions, while 300 has two
nonequivalent Sn O interactions. Upon the recrystallization of 3 from hexane, only a single structural form is
3 3 3
3 3 3
observed, 30. The Sn E distances in 30, 300, and 6 are 71.3, 73.5 and 72.9, and 76.3% of the ΣvdW radii,
respectively. The meta- and para-substituted isomers of 3 (10, 11) exhibit a distortion at the tin atom due to self-
3 3 3
association via intermolecular Sn Cl interactions, resulting in polymeric structures. 119Sn NMR spectroscopy
suggests that the intramolecular Sn E interactions persist in solution for the dichloride compounds 3 and 6.
3 3 3
3 3 3
Introduction
and 2.1 These examples were an illustration of the general
ability of tetravalent tin to be coordinated by Lewis bases
such as N, S, and O, via both inter- and intramolecular
interactions.2
We recently demonstrated the capacity of the o-methoxy-
benzyl ligand, and its thio analog, to significantly modify the
tetrahedral geometry at a central tetravalent tin atom via
strong intramolecular Sn E (E = O, S) secondary bonding
in the compounds (o-MeEC6H4CH2)Ph3-nSnCln, n = 0, 1,
Inter(intra)molecular secondary bonding of the type Sn
E
3 3 3
3 3 3
(E = S, O, N) has been suggested to be important with respect
to the biological activity of organotins (OTs).3 Our current
interest is related to the specific capacity of OTs to reduce the
capacity of human natural killer (HNK) cells to function.4a
*To whom correspondence should be addressed. E-mail: kpannell@
utep.edu.
ꢀ
(1) Munguıa, T.; Lopez-Cardoso, M.; Cervantes-Lee, F.; Pannell, K. H.
Inorg. Chem. 2007, 46, 1305–1314.
(2) (a) Rotar, A.; Varga, R. A.; Jurkschat, K.; Silvestru, C. J. Organomet.
Chem. 2009, 694, 1385–1392. (b) Varga, R. A.; Jurkschat, K.; Silvestru, C. Eur.
J. Inorg. Chem. 2008, 708–716. (c) Rotar, A.; Sch€urmann, M.; Varga, R. A.;
Silvestru, C.; Jurkschat, K. Z. Anorg. Allg. Chem. 2008, 634, 1533–1536. (d)
(3) (a) Katsoulakou, E.; Tiliakos, M.; Papaefstathiou, G.; Terzis, A.;
Raptopoulou, C.; Geromichalos, G.; Papazisis, K.; Papi, R.; Pantazaki, A.;
Kyriakidis, D.; Cordopatis, P.; Manessi-Zoupa, E. J. Inorg. Biochem. 2008,
102, 1397–1405. (b) Basu, B. T. S.; Masharing, C.; Ruisi, G.; Jirasko, R.;
Holcapek, M.; de Vos, D.; Wolstenholme, D.; Linden, A. J. Organomet. Chem.
2007, 692, 4849–4862. (c) Pellerito, L.; Nagy, L. Coord. Chem. Rev. 2002, 224,
111–150. (d) Gielen, M.; Biesemans, M.; deVos, D.; Willem, R. J. Inorg.
Biochem. 2000, 79, 139–145. (d) Blunden, S. J.; Patel, B. N.; Smith, P. J.;
Sugavanam, B Appl. Organomet. Chem. 1987, 1, 241–4.
(4) (a) Whalen, M. M. Impact of Organotin Compounds on the Function
of Human Natural Killer Cells. In Tin Chemistry: Fundamentals, Frontiers
and Applications; Davies, A. G., Gielen, M., Pannell, K. H., Tiekink, E. R. T. J.,
Eds.; Wiley: New York, 2008; pp 469-479. (b) Whalen, M. M.; Loganathan,
B. G.; Kannan, K. Environ. Res. 1999, 81, 108–116. (c) Gomez, F. D.; Apodaca,
P.; Holloway, L. N.; Pannell, K. H.; Whalen, M. M. Environ. Toxicol.
Pharmacol. 2007, 23, 18–24. (d) Holloway, L. N.; Pannell, K. H.; Whalen,
M. M. Environ. Toxicol. Pharmacol. 2008, 25, 43–50. (e) Preliminary results
from exposing HNK cells to this type of OT confirm a significant change in
activity: Whalen, M. M. Private communication.
ꢀ
ꢀ
Munguia, T.; Cervantes-Lee, F.; Parkanyi, L. Organotin-Sulfur Intramolecular
Interactions: An Overview of Current and Past Compounds and the Biological
Implications of Sn--S Interactions. In Modern Aspects of Main Group Chem-
istry; Lattman, M., Kemp, R. A., Eds.; American Chemical Society: Washington,
DC, 2006; ACS Symposium Series 917, pp 422-435. (e) Jastrzebski, J. T. B. H.;
van Koten, G. Adv. Organomet. Chem. 1993, 35, 241–294. (f) Zickgraf, A.;
Beuter, M.; Kolb, U.; Drager, M.; Tozer, R.; Dakternieks, D.; Jurkschat, K. Inorg.
Chim. Acta 1998, 275-276, 203–214. (g) Dakternieks, D.; Jurkschat, K.; Tozer,
R.; Hook, J.; Tiekink, E. R. T. Organometallics 1997, 16, 3696–3706. (h) Davies,
A. G. In Tin. In Comprehensive Organometallic Chemistry II: A Review of the
Literature 1982-1994; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.;
Elsevier Science Inc.: Tarrytown, NY, 1995; Vol. 2. (i) Kolb, U.; Beuter, M.;
Gerner, M.; Drager, M. Organometallics 1994, 13, 4413–4425. (j) Harrison, P. G.
Compounds of Tin: General Trends. In Chemistry of Tin; Harrison, P. G., Ed.;
Chapman and Hall: New York, 1989.
r
pubs.acs.org/IC
Published on Web 01/04/2010
2010 American Chemical Society

Article
Inorganic Chemistry, Vol. 49, No. 3, 2010 961
Table 1. Crystal Data and Refinement Parameters
cryst structure
3A (30 and 300)
3B (30)
6
10
11
formula
fw
3(C16H18Cl2O2 Sn) THF C16H18Cl2O2Sn
431.89
C16H18Cl2S2Sn
464.01
monoclinic
C2/c
18.641(3)
8.2600(12)
14.947(2)
90
125.650(2)
90
1870.1(5)
4
1.648
1.866
920
C16H18Cl2O2Sn
431.89
monoclinic
C2/c
29.155(3)
4.9005(5)
12.1948(12)
90
104.941(2)
90
1683.4(3)
4
1.704
1.836
856
C16H18Cl2O2Sn
431.89
orthorhombic
Pnma
9.5239(11)
29.418(3)
6.0974(7)
90
90
90
1708.3(3)
4
1.679
3
1367.79
orthorhombic
C2221
cryst syst
space group
triclinic
P1
˚
a (A)
11.2125(13)
18.4339(13)
26.755(2)
90
90
90
5529.9(9)
4
1.643
1.683
2728
7.4570(12)
8.5940(14)
14.043(2)
89.699(2)
81.920(2)
81.005(2)
880.0(2)
2
1.630
1.756
428
298(2)
50.00, 98.8
˚
b (A)
˚
c (A)
R (deg)
β (deg)
γ (deg)
3
˚
V (A )
Z
F
calcd (g cm-3
)
μ(Mo KR) (mm-1
F(000)
T (K)
)
1.809
856
298(2)
53.90, 100
100(2)
46.50, 100
293(2)
50.00, 100
298(2)
53.50, 100
2θmax for data collection (deg),
% completed
index ranges: -h þh, -k þk, -l þl
-12 12, -20 20,
-29 29
23064
-8 8, -10 10,
-16 16
8299
-22, 22, -9,
9, -17, 17
8708
-36 36, -6 6,
-15 15
8752
-12 12,
-37 37, -7 7
17629
1901[0.0851]
total number reflns
independent reflns [Rint
refinement methods
data/restraints/params
goodness-of-fit on F2
R1 [I > 2σ(I)]
]
3968[0.0453]
3058[0.0369]
1654[0.0186]
full-matrix least-squares on F2
1791[0.0524]
3968/0/314
1.154
0.0333
3058/0/190
0.880
0.0404
1654/57/97
1.023
0.0241
1791/0/96
1.054
0.0408
1901/0/100
1.140
0.0543
-3
˚
largest difference in peak and hole (e A
)
0.969 and -0.322
0.618 and -0.312 0.669 and -0.265 0.815 and -0.378 2.251 and -0.703
Since these cells are an essential part of our immune system,
and OTs are found in our bloodstream from societal uses,4b
there is a driving force to reduce this exposure. Since clear
structure-activity relationships have been discovered in the
interactions of OTs with HNK cells,4a,c,d we have initiated a
study of simple OTs in which O, S, and N atoms are placed
within the coordination sphere, but without direct σ bonding to
the central tin atom, in the expectation of modifying this
biological activity via potential intramolecular interactions.
We now report OTs with two functionalized benzyl groups
with MeO- and MeS- substituents which can permit the
formation of penta- or hexa-coordinated tin atoms.4e We have
also investigated the meta and para isomers of the O-containing
oil. The X-ray intensity data were collected with SMART6a on a
Bruker APEX CCD diffractometer with monochromatized Mo
KR radiation (λ = 0.71073 A). Cell refinement and data
reduction were carried out with SAINT; incident beam and
decay corrections were done with SADABS in the SAINT-Plus
suite, v.6.23c.6b The structures were solved by direct methods
with SHELXS and refined by full-matrix least-squares techni-
ques with SHELXL in the SHELXTL suite, v.6.10.6c The
corresponding experimental parameters for each compound
are summarized in Table 1.
˚
Synthesis of 2-Ethylbenzyl Chloride. 2-Ethylbenzyl alcohol
(5 mL, 36.7 mmol) dissolved in benzene (10 mL) was added
dropwise into a three-neck flask containing SOCl2 (5.25 mL,
73.4 mmol) and benzene (40 mL) at 0 °C. After this addition,
pyridine (6 mL, 73.4 mmol dissolved in 5 mL of benzene) was
added dropwise, and the mixture was stirred for 30 min. The
mixture was then refluxed for 2 h and transferred immediately to
an ice bath for 20 min. Ice (40 g) was added and the pH increased
to 6 with a saturated solution of NaHCO3. The product was then
extracted with diethylether three times; the ethereal fractions
were collected and the solvent evaporated. The final product was
distilled at 6 mmHg, bp 60-62 °C. Yield: 2.72 g (48%). 1H NMR
(CDCl3): δ 2.07 (3H, t, -CH3, J = 7.5 Hz), 3.54 (2, q, -CH2CH3,
ligand to determine if intermolecular E Sn interactions can
3 3 3
be observed, since the geometry precludes intramolecular
interactions.
Experimental Section
Synthesis. All manipulations were carried out under nitrogen
atmospheres using standard Schlenk techniques. Reagent-grade
tetrahydrofuran (THF) was dried and distilled under nitrogen
from a sodium benzophenone ketyl solution. Toluene, benzene,
and hexane were dried and distilled from Na ribbon; pyridine was
dried and distilled from NaOH. Diphenyltindichloride was pur-
chased from Gelest. 2-Methoxybenzyl chloride, 2-ethylbenzyl
alcohol, thionyl chloride, metallic tin, 1 M tin tetrachloride in
methylene chloride, 1-bromo-3-chloropropane, methanethiol,
and 1 M HCl in diethyl ether were purchased from Aldrich.
2-Thiomethylbenzyl chloride was synthesized using published
methods.5 NMR spectra, 1H, 13C, and 119Sn, were recorded on a
Bruker 300 MHz operating spectrometer at 300.00, 75.422, and
111.853 MHz, respectively, using CDCl3 or C6D6 as the solvent.
Elemental analyses were performed by Galbraith Laboratories.
X-Ray Diffraction. Crystals suitable for X-ray diffraction
were obtained for compounds 3, 6, 10, and 11, and each was
mounted on a cryoloop in a random orientation using paratone
J = 7.5 Hz), 5.41 (2H, s, -CH2Cl), 8.26-7.75 (4H, m, Ph). 13
C
NMR (CDCl3): δ 15.3 (-CH3), 25.3 (-CH2CH3), 44.4
(-CH2Cl), 126.4, 129.0, 129.2, 130.3, 135.1, 143.1 (-CH, Ph).
Synthesis of [(o-MeOC6H4)CH2]2SnPh2 (1). Ph2SnCl2 (1.99 g,
5.81 mmol) was added to a mixture of 2-methoxybenzyl chloride
(2 g, 12.8 mmol) and Mg turnings (0.31 g, 12.8 mmol) in THF
(50mL) at0°C. The reaction mixture was kept at 0 °Candallowed
to stir overnight. The solvent was removed under reduced pres-
sure, and the product was extracted with hexane and filtered. The
crude material was recrystallized from hexane at -20 °C to yield 1
as a white solid. Yield: 1.48 g (45%); mp 68-70 °C. Anal. Calcd
for C28H28O2Sn: C, 65.27; H, 5.48. Found: C, 65.01; H, 5.47.
1HNMR(CDCl3):δ3.29 (4H, s, Ar-CH2Sn, 2J(117/119Sn,1H) =
20.12/33.26 Hz), 4.15 (6H, s, Me-O-Ar), 8.00-7.31 (18H, m,
(6) (a) Sheldrick, G. M. SMART; Bruker AXS, Inc.: Madison, WI, 2000. (b)
SAINT-Plus, version 6.23c; Bruker AXS, Inc.: Madison, WI. (c) SHELXTL, v.
6.10; Bruker AXS, Inc.: Madison, WI.
(5) Traynelis, V. J.; Borgnaes, D. M. J. Org. Chem. 1972, 37, 3824–3826.

962 Inorganic Chemistry, Vol. 49, No. 3, 2010
Vargas-Pineda et al.
Ph, Ar). 13C NMR (CDCl3): δ 15.49 (2C, Ar-CH2Sn,
(2C, Ar-CH2Me), 125.72 (2C, C5-Ar), 126.44 (2C, C4-Ar),
128.36 (2C), 128.40 (2C), 128.74 (1C, C4-Ph), 128.82
(2C), 130.05 (1C, C1-Ph), 135.46 (2C, C3-Ph), 135.93 (2C,
C2-Ar), 140.44 (2C, C1-Ar). 119Sn NMR (CDCl3): δ -11.9.
Anal. Calcd for C24H27ClSn: C, 61.38; H, 5.79. Found: C, 61.42;
H, 5.82.
1J(13C,117 119
Sn) = 312.74/327.23 Hz), 54.60 (2C, Me-O-Ar),
/
109.51 (2C, C3-Ar, 4J(13C,119Sn) = 12.9 Hz), 120.50 (2C,
C5-Ar, 4J(13C,119Sn) = 11.7 Hz), 125.12 (2C, C4-Ar,
5J(13C,119Sn) =15.67 Hz), 127.97 (4C, C2-Ph), 128.36, (2C,
C4-Ph), 128.67 (2C, C6-Ar, 3J(13C,119Sn) = 29.7 Hz), 130.34
(2C, C1-Ar, 2J(13C,119Sn) = 21.0 Hz), 136.37 (4C, C3-Ph,
Synthesis of [(o-MeOC6H4)CH2]2SnCl2 (3). To tin powder
(1.52 g, 11.6 mmol) was added three drops of water, and the
mixture was kneaded together. The resulting material was
suspended in 50 mL of toluene under efficient stirring and
heated by an external boiling water bath. To this suspension
was added dropwise 2-methoxybenzyl chloride (2 g, 12.8 mmol)
over 3 min. After 4 h of reflux, the solution was cooled and
filtered, and the solvent was removed under reduced pressure.
The crude material was recrystallized from hexane at -20 °C to
yield 3 as a white solid, 1.93 g (70%), mp 92-94 °C.
3J(13C,119Sn) = 33.37 Hz), 141.36 (2C, C1-Ph, 1J(13C,117 119
Sn) =
/
434.17/454.57 Hz), 155.90 (2C, C2-Ph, 3J(13C,119Sn) = 10.80 Hz).
119Sn NMR (CDCl3): δ -96.6.
Using the same synthetic approach we obtained the following
compounds:
[(o-MeSC6H4)CH2]2SnPh2 (4).Yield: 1.6 g (50%); mp 72-74 °C.
1H NMR (CDCl3): δ 2.87 (6H, s, Me-S-Ar), 3.45 (4H, s,
Ar-CH2-Sn, 2J(117/119Sn,1H) = 19.88/31.51 Hz), 7.95-7.74
(18H, m, Ph, Ar). 13C NMR (CDCl3): δ 15.57 (2C, Me-S-Ar),
22.84 (2C, Ar-CH2Sn, 1J(13C,117 119
/ Sn) = 294.75/308.25 Hz),
1H NMR (CDCl3): δ 3.66 (4H, s, Ar-CH2-Sn, 2J(117/119Sn,-
1H) = 20.58/48.84 Hz), 3.95 (6H, s, Ar-O-Me), 7.90-7.17
(8H, m, Ar). 13C NMR (CDCl3): δ 55.15 (2C, Ar-O-Me),
31.09 (2C, Ar-CH2Sn, 1J(13C,119Sn) = 539.25/564.3 Hz),
109.41 (2C, C3-Ar, 4J(13C,119Sn) = 19.87 Hz), 121.40
124.86 (2C, Ar), 124.88 (2C, Ar), 124.96, (2C, Ar), 128.00 (4C,
C2-Ph), 128.07 (2C, C4-Ph), 128.40 (2C, C6-Ar), 135.40 (2C,
C2-Ar, 3J(13C,119Sn
= 25.27 Hz), 136.55 (4C, C3-Ph,
2
3J(13C,119Sn) = 33.9 Hz), 139.69 (2C, C1-Ar, J(13C,119Sn) =
42.3 Hz), 141.07 (2C, C1-Ph, J(13C,119Sn) = 436.42/470.1 Hz).
1
2
(2C, C5-Ar), 125.15 (2C, C1-Ar, J(13C,119Sn) = 53.55 Hz),
5
119Sn NMR (CDCl3): δ -98.8. Anal. Calcd for C28H28S2Sn: C,
61.44; H, 5.16. Found: C, 61.50; H, 5.13.
127.76 (2C, C4-Ar, J(13C-119Sn) = 18.75 Hz), 129.46 (2C,
C6-Ar, 3J(13C,119Sn) = 43.05 Hz), 155.05 (2C, C2-Ar,
3J(13C,119Sn) = 35.85 Hz). 119Sn NMR (CDCl3): δ -35.39.
Anal. Calcd for C16H18Cl2O2Sn: C, 44.49; H, 4.20. Found: C,
45.74; H, 4.17.
1
[(o-EtC6H4)CH2]2SnPh2 (7). Yield: 2.15 g (65%). H NMR
3
(CDCl3): δ 1.79 (6H, t, Ar-CH2Me, J(H,H) = 7.5 Hz), 3.07
(4H, q, -CH2CH3, 3J(H,H) = 7.5 Hz), 3.41 (4H, s, Ar-CH2-
Sn, 2J(117/119Sn, 1H) = 31.72/32.74 Hz), 8.04-7.67 (18H, m, Ph,
Ar). 13C NMR (CDCl3): δ 14.01 (2C, Ar-CH2Me), 17.53 (2C,
Ar-CH2Sn, 1J(13C,119/117Sn) = 290.82/304.25 Hz), 26.36 (2C,
Also, the following compounds were synthesized using the
same general approach:
[(o-MeSC6H4)CH2]2SnCl2 (6). Yield: 1.75g (65%); mp
1
Ar-CH2Me), 124.55 (2C, C3-Ar, J(13C,119Sn) = 16.87 Hz),
4
154-156 °C. H NMR (CDCl3): δ 2.95 (6H, s, Ar-S-CH3),
3.96 (4H, s, Ar-CH2-Sn, 2J(117/119Sn,1H) = 12.95/33.01 Hz),
8.01-7.89 (8H, m, Ar). 13C NMR (CDCl3): δ 15.48 (2C,
Ar-S-CH3), 41.78 (2C, Ar-CH2Sn, 1J(13C,117/119Sn) =
541.05/566.25 Hz), 127.18 (2C), 127.48 (2C), 127.66 (2C),
126.15 (2C, C-Ar, J(13C,119Sn) = 13.8 Hz), 128.01 (2C, C-Ar,
J(13C,119Sn) = 14.55 Hz), 128.49 (2C, C4-Ph), 128.5 (4C, C2-
Ph), 128.90 (2C, C-Ar, J(13C,119Sn) = 10.65 Hz), 136.63 (4C,
C3-Ph, 3J(13C,119Sn) = 33.37 Hz), 138.89 (2C, C1-Ph), 139.69
(2C, C2-Ar). 119Sn NMR (CDCl3): δ -103.7. Anal. Calcd for
C30H32Sn: C, 70.47; H, 6.31. Found: C, 70.51; H, 6.39.
Synthesis of [(o-MeOC6H4)CH2]2SnPhCl (2). A solution of
hydrogen chloride (1.0 M in diethyl ether, 1.94 mL, 1.94 mmol)
was added dropwise to a solution of 1 (1 g, 1.94 mmol) in 10 mL
of dried benzene. After 30 min, the reaction was complete, and
the solvent was removed under reduced pressure. It was isolated
as oil from a hexane solution of the crude left at -20 °C, 0.32 g
(35%).
3
130.00 (2C, C6-Ar, J(13C,119Sn) = 76.125 Hz), 134.50 (2C,
C2-Ar, 3J(13C,119Sn) = 26.10 Hz), 137.58 (2C, C1-Ar,
2J(13C,119Sn) = 51.45 Hz). 119Sn NMR (CDCl3): δ -54.7. Anal.
Calcd for C16H18Cl2S2Sn: C, 41.41; H, 3.91. Found: C, 41.79;
H, 3.74.
[(o-EtC6H41)CH2]2SnCl2 (9). Yield: 2.39
g (70%); mp
110-112 °C. H NMR (CDCl3): δ 1.89 (6H, t, Ar-CH2-Me,
3J(1H,1H) = 7.4 Hz, 3.15 (4H, q, Ar-CH2-Me, 3J(1H,1H) =
7.4 Hz), 3.90 (4H, s, Ar-CH2Sn, 2J(117/119Sn,1H) = 38.16/
39.69 Hz), 7.88-7.67 (8H, m, Ar). 13C NMR (CDCl3): δ 14.42
(Ar-CH2-Me), 26.43 (Ar-CH2-Me), 31.24 (Ar-CH2-Sn,
1J(13C,119/117Sn) = 344.25/361.95 Hz), 126.68 (2C, J(13C,119Sn) =
26.1 Hz), 127.04 (2C, J(13C,119Sn) = 31.12 Hz), 128.61 (2C,
1H NMR (CDCl3): δ 3.35 (4H, s, Ar-CH2-Sn, 2J(117/119Sn,-
1H) = 20.98/34.12 Hz), 4.07 (6H, s, Ar-OMe), 8.03-7.20 (13H,
m, Ar, Ph). 13C NMR (CDCl3): δ 21.76 (2C, Ar-CH2-Sn), 54.57
(2C, Ar-OMe), 109.38 (2C, C3-Ar), 121.01 (2C, C5-Ar), 126.53
(2C, C4-Ar), 128.52 (2C, C6-Ar), 128.90 (1C, C4-Ph), 129.46
(2C, C1-Ar), 127.97 (2C, C2-Ph), 135.38 (2C, C3-Ph), 142.25
(1C, C1-Ph), 155.68 (2C, C2-Ar). 119Sn NMR (CDCl3):δ-11.9.
Anal. Calcd for C22H23ClO2Sn: C, 55.80; H, 4.90. Found: C, 56.01;
H, 5.04.
3
J(13C,119Sn) = 26.62 Hz), 129.27 (2C, C6-Ar, J(13C,119Sn) =
43.27 Hz), 132.55 (2C, C2-Ar, 3J(13C-119Sn) = 58.5 Hz),
141.02 (2C, C1-Ar, 2J(13C,119Sn) = 42.3 Hz). 119Sn NMR
(CDCl3): δ 40.3. Anal. Calcd for C18H22Cl2Sn: C, 50.51; H, 5.18.
Found: C, 50.42; H, 5.03.
[(m-MeOC6H4)CH2]2SnCl2 (10). Yield: 0.52 g (57%); mp
[(o-MeSC6H4)CH2]2SnPhCl (5). Yield as a liquid product:
0.35g (38%). 1H NMR (CDCl3): δ 2.16 (6H, s, Ar-SMe), 3.07
(4H, s, Ar-CH2-Sn, 2J(117/119Sn,1H) = 20.43/33.18 Hz),
7.74-6.99 (13H, m, Ar, Ph). 13C NMR (CDCl3): δ 16.37 (2C,
Ar-SMe), 29.52 (Ar-CH2-Sn), 125.84 (2C, C5-Ar), 126.10
(2C, C4-Ar), 128.39 (2C), 128.51 (2C), 128.76 (1C, C4-Ph),
129.03 (2C, C6-Ar), 134.94 (2C, C2-Ar), 135.39 (2C, C3-Ph),
138.41 (1C, C1-Ph), 141.75 (2C, C1-Ar). 119Sn NMR (CDCl3):
δ -20.2. Anal. Calcd for C22H23ClS2Sn: C, 52.25; H, 4.58.
Found: C, 52.32; H, 4.69.
1
142-145 °C. H NMR (CDCl3): δ 3.08 (4H, s, Ar-CH2-Sn,
2J(117/119Sn,1H) = 41.16/48.84 Hz), 3.70 (6H, s, Ar-O-Me),
6.54-6.70 (8H, m, Ar). 13C NMR (CDCl3): δ 55.1 (2C, Ar-O-
Me), 32.4 (2C, Ar-CH2-Sn), 112.1 (2C, C2-Ar), 113.6 (2C,
C4-Ar), 120.5 (2C, C5-Ar), 130.1 (2C, C6-Ar), 136.2 (2C,
C1-Ar), 150.2 (2C, C3-Ar). 119Sn NMR (CDCl3): δ 31.8.
Anal. Calcd for C16H18Cl2O2Sn: C, 44.49; H, 4.20. Found: C,
45.74; H, 4.17.
[(p-MeOC6H4)CH2]2SnCl2 (11). Yield: 0.62 g (70%); mp
138-141 °C. 1H NMR (CDCl3): δ 3.08 (4H, s, CH2-Sn,
2J(117/119Sn,1H) = 41.16/48.84 Hz), 3.74 (6H, s, Ar-O-Me),
6.70-6.6.80 (8H, m, Ar). 13C NMR (CDCl3): δ 55.2 (2C,
Ar-O-CH3), 31.6 (2C, Ar-CH2-Sn), 114.8 (2C, C3-Ar),
126.3 (2C, C1-Ar), 129.3 (2C, C2-Ar), 158.2 (2C, C4-Ar).
119Sn NMR (CDCl3): δ 30.7
[(o-EtC6H4)CH2]2SnPhCl (8). Yield: 2.47 g (90%). 1H NMR
(CDCl3): δ 1.85 (6H, t, Ar-CH2Me, 3J(1H,1H) = 7.4 Hz), 3.14
3
(4H, q, Ar-CH2Me, J(1H,1H) = 7.4 Hz), 3.64 (4H, s, Ar-
CH2-Sn, 2J(117/119Sn,1H) = 33.27/35.30 Hz), 8.12-7.67 (13H,
m, Ar, Ph). 13C NMR (CDCl3): δ 14.32 (2C, Ar-CH2Me), 24.08
(2C, Ar-CH2Sn, 1J(13C,119/117Sn) = 287.44/318.72 Hz), 26.45

Article
Inorganic Chemistry, Vol. 49, No. 3, 2010 963
Figure 1. ORTEP diagrams of conformers 30 (left) and 300 (right) found in the polymorphs of 3. Each conformer is independently oriented, and the THF
molecule is excluded for clarity.
Results and Discussion
We prepared the [(o-MeEC6H4)CH2]2Ph2-nClnSn com-
pounds using the reactions outlined in eqs 1-3. The syntheses
of the m- and p-[(MeOC6H4)CH2]2SnCl2 isomers, 10 and 11,
followed the reaction noted in eq 3.
Ph2SnCl2 þ 2½ðo-MeEC6H4ÞCH2ꢀMgCl
f ½ðo-MeEC6H4ÞCH2ꢀ2Ph2Sn þ 2MgCl2
ð1Þ
E ¼ O ð1Þ, E ¼ S ð4Þ, E ¼ CH2 ð7Þ
½ðo-MeEC6H4ÞCH2ꢀ2Ph2Sn þ HCl=Et2O
f ½ðo-MeEC6H4ÞCH2ꢀ2PhSnCl þ PhH
ð2Þ
E ¼ O ð2Þ, E ¼ S ð5Þ, E ¼ CH2 ð8Þ
Figure 2. ORTEP diagram of compound 6.
2ðo-MeEC6H4ÞCH2Cl þ Sn0 f ½ðo-MeEC6H4ÞCH2ꢀ SnCl2
2
ð3Þ
methylene group. We also synthesized the unsubstituted
dibenzyl compound (C6H4CH2)2SnCl2 (12). Within this
family of organotins, the O- and S-substituted compounds,
3 and 6, exhibit a clear change of chemical shift compared to
those where no intramolecular secondary bonding can be
expected, that is, 12 and 9. The 119Sn chemical shifts for the
latter are 35.4 and 40.3 ppm, respectively, whereas the ortho-
substituted MeE-benzyl compounds exhibit significantly
shifted resonances at -54.7 ppm (E = S, 6) and -35.4 ppm
(E = O, 3). This is a >70 ppm upfield shift with respect to
E ¼ O ð3Þ, E ¼ S ð6Þ, E ¼ CH2 ð9Þ
The progress of the chlorination reaction, eq 2, was con-
veniently monitored by 119Sn NMR spectroscopy (without
locking) because of the significant difference in chemical shift
of the reactants and products: 1 f 2 (-96.6 f -11.9 ppm),
4 f 5 (-98.8 f -20.2 ppm), and 7 f 8 (-103.7 f
-11.9 ppm). The “direct process” reaction between metallic
tin and the benzyl chlorides used to obtain the bis-benzyltin
dichlorides, eq 3, results in good to high yields for all of the
examples studied.
9 and 12, reflecting significant Sn E intramolecular inter-
3 3 3
actions, even in solution. It can be also observed that the
intramolecular coordination is stronger for 6 than for 3, as
judged by the greater upfield shift observed in the 119Sn NMR
spectrum of 6.
Previous studies have indicated that 119Sn NMR spectra
exhibit an upfield shift of more than 40 ppm upon increasing
the coordination number at the tin atom.7 We have pre-
pared [(o-CH3CH2C6H4)CH2]2Ph2-nClnSn to permit us
to note the variation upon introducing the O and S
Lewis base atoms as replacements for the noncoordinating
In the case of the meta and para isomers [(m(p)-MeO-
C6H4)CH2]2SnCl2, 10 and 11, the 119Sn NMR chemical
shifts at 31.9 and 30.7 ppm, respectively. These values
are similar to the benzyl compounds (9 and 12) without
any form of intramolecular bonding, suggesting that, at
least in solution, there are no significant intermolecular
interactions.
(7) (a) Wrackmeyer, B. Annu. Rep. NMR Spectrosc. 1999, 38, 203–264. (b)
ibid. 1985, 16, 73-186.

964 Inorganic Chemistry, Vol. 49, No. 3, 2010
Vargas-Pineda et al.
Figure 3. ORTEP diagram of compound 10.
Figure 4. ORTEP diagram of compound 11.
Crystal Structure Analysis. X-ray-quality crystals of
compounds 3, 6, 10, and 11 were obtained and used to
determine the molecular structures which are presented in
Figures 1, 2, 3, and 4, respectively. Selected geometrical
parameters are summarized in Tables 2 and 3 and illustrate
that compounds the various Sn-C bond distances for this
series of exhibit no significant variation within the experi-
mental error from the expected values and fall within the sum
those reported for dichloro-bis(2,6-bis(methoxymethyl)-
phenyl)-(IV),10 2.508(2) and 2.343(2) A, that correspond
˚
to 68.0 and 63.5% of the sum of VdW radii and longer than
˚
therelatedSn O distance of 2.559(4) A in bis(2-methoxy-
3 3 3
3-tbutyl-5-methylphenyl)methaneSnPhCl2.2g The Sn atoms
in these crystal structures have four covalent bonds and
two short contacts [4 þ 2] with the oxygen atoms. Thus,
the coordination geometry at the tin atom can be
described as a distorted bicapped tetrahedral or as a
distorted octahedral geometry; however, the analyses of
the angles around the tin atom show that it is best
described as a distorted bicapped tetrahedron. The sum
of all angles around the central atom in an ideal tetra-
hedral geometry is 1549, while for an ideal octahedral
geometry, it is 1620. For the structures 30 and 300, the
observed values are 1552 and 1562, showing that they
have 95.5 and 81.5% bicapped tetrahedral geometry
character. The choice of the bicapped tetrahedral struc-
ture over octahedral shows that the donor strength of
the O atoms in these structures is apparently insufficient
to hybridize the tin atom, a situation similar to that well-
recognized in related hexa-substituted silicon compounds11
8
˚
of the covalent radii [2.15(4) A] for tin and carbon (Table 2).
For compound 3, we found two different conformers in
the crystal structure obtained from hexane/THF, 30
(symmetry related) and 300 (asymmetric), both illustrated
in Figure 1. Since this crystal structure included a THF
molecule, we surmised that a different polymorph could be
obtained by recrystallization from hexane, and indeed a
new polymorph 3a was obtained composed of only 300. In 30
and 300, no short intermolecular contact is observed between
Sn and Cl atoms, but intramolecular interactions of both
oxygen atoms with the tin atom are observed [r(Sn O) =
3 3 3
0
00
˚
2.630(4) for 3 , 2.692(4) and 2.711(4) A for 3 ]. These
interactions are 71.3, 72.9, and 73.5% of the ΣvdW radii
9
(3.69 A), respectively. These distances are longer than
˚
€
(8) (a) Pyykko, P.; Atsumi, M. Chem.;Eur. J. 2009, 15, 186–197. (b)
(11) (a) Kost, D.; Gostevskii, B.; Kalikhman, I. Pure Appl. Chem. 2007,
79, 1125–1134. (b) Kalikhman, I.; Gostevskii, B.; Botoshansky, M.; Kaftory, M;
Tessier, C. A.; Panzner, M. J.; Youngs, W. J.; Kost, D. Organometallics 2006, 25,
1252–1258. (d) Kocher, N.; Henn, J.; Gostevskii, B.; Kost, D.; Kalikhman, I.;
Engles, B.; Stalke, D. J. Am. Chem. Soc. 2004, 126, 5563.
ꢀ
ꢀ
Cordero, B.; Gomez, V.; Platero-Prats, A. E.; Reves, M.; Echeverría, J.; Cremades,
E.; Barragan, F.; Alvarez, S. Dalton Trans. 2008, 2832–2838.
(9) Bondi, A. J. Phys. Chem. 1964, 68, 441–451.
(10) Kasna, B.; Jambor, R.; Dostal, L.; Cisarova, I.; Holecek, J. J.
Organomet. Chem. 2006, 691, 1554–1559.
ꢀ

Article
Inorganic Chemistry, Vol. 49, No. 3, 2010 965
a
˚
Table 2. Selected Bond Lengths [A] and Angles [deg]
3A, 30, X = Ob
3A, 300, X = O
3B, 300, X = O
6, X = Sc
10, X = Cl
11, X = Cl
Sn(1)-C(1)
Sn(1)-C(9)
Sn(1)-Cl(1)
Sn(1)-Cl(9)
2.136(6)
2.374(2)
2.630(4)
2.142(5)
2.150(6)
2.381(1)
2.381(1)
2.692(4)
2.711(4)
2.138(5)
2.151(7)
2.379(2)
2.372(2)
2.666(4)
2.715(4)
134.79(26)
105.66(17)
103.27(14)
103.99(20)
106.49(19)
96.37(06)
2.143(3)
2.399(1)
3.029(1)
2.135(4)
2.358(1)
3.816
2.136(5)
2.356(2)
2.372(2)
3.943
Sn(1) X(1)
3 3 3
Sn(1) X(2)
3.502
3 3 3
C(1)-Sn(1)-C(9)
C(1)-Sn(1)-Cl(1)
C(1)-Sn(1)-Cl(2)
C(9)-Sn(1)-Cl(1)
C(9)-Sn(1)-Cl(2)
Cl(1)-Sn(1)-Cl(2)
sym. operation
131.7(3)
105.03(19)
107.15(16)
107.15(16)
105.03(19)
94.71(8)
134.7(2)
142.8(2)
102.83(9)
101.7(1)
101.7(1)
102.83(9)
96.66(4)
133.99(23)
104.98(13)
104.44(13)
104.44(13)
104.98(13)
98.99(6)
127.73(27)
110.32(17)
104.86(14)
110.32(18)
104.86 (14)
92.37(7)
101.68(16)
109.21(17)
106.12(17)
102.30(17)
96.63(6)
2 - x, y, 1.5 - z
-x þ 2, y, -z þ 1/2
-x þ 2, y, -z þ 1/2
x, 1.5 - y, z
a The atoms C9, X2, and Cl2 for compounds 30, 6, 10, and 11 were generated with the appropriate symmetry operation listed at the end of each column,
from the positions of C1, X1, and Cl1, respectively. b The X denoted in each column corresponds to the atom which is making the intra- or intermolecular
contact. c For compound 6, Cl(1) and Cl(2) in the table correspond to Cl(1A) and Cl(1), respectively, in the figures and CIF file.
Table 3. Selected Angles [deg]a
3A, 30, X = Ob
3A, 300, X = O
3B, 300, X = O
6, X = Sc
10, X = Cld
11, X = Cld
X(1) Sn(1)-Cl(1)
82.38(10)
172.88(10)
67.61(18)
85.93(09)
167.72(10)
66.23(18)
84.94(19)
101.26(12)
165.13(09)
79.12(09)
85.64(19)
65.84(18)
80.78(09)
168.10(11)
66.80(16)
85.39(21)
101.45(13)
169.82(10)
83.41(10)
84.23(18)
66.53(20)
85.01(3)
171.63(2)n
68.81(9)
85.88(10)
94.53(4)
171.63(2)
85.01(3)
85.88(10)
68.81(9)
102.49(4)
158.52(3)
69.64(12)
69.99(12)
56.03(3)
158.52(3)
102.49(4)
69.99(12)
69.64(12)
57.63(5)
149.99(7)
80.49(18)
80.49(18)
144.39(4)
157.98(4)
65.61(6)
84.06(17)
84.06(17)
x, 1.5 - y, z
3 3 3
X(1) Sn(1)-Cl(2)
3 3 3
X(1)
X(1)
Sn(1)-C(1)
Sn(1)-C(2)
3 3 3
3 3 3
82.06(21)
X(1) Sn(1) X(2)
101.23(18)
172.88(10)
82.38(10)
82.06(21)
67.61(18)
3 3 3
3 3 3
X(2) Sn(1)-Cl(1)
3 3 3
X(2) Sn(1)-Cl(2)
3 3 3
X(2)
X(2)
Sn(1)-C(1)
Sn(1)-C(2)
3 3 3
3 3 3
2 - x, y, 1.5 - z
-x þ 2, y, -z þ 1/2
-x þ 2, y, -z þ 1/2
a The atoms X1, C1, Cl1, C3, C8, C3, and C2 are equivalents to X2, C2, Cl2, C11, and C10, respectively, for compounds 30, 6, 10, and 11 by the
appropriate symop listed at the end of each column. b The X denoted in each column corresponds to the atom which is making the intra- or intermolecular
contact. c For compound 6, Cl(1) and Cl(2) in the table correspond to Cl(1A) and Cl(1), respectively, in the figures and CIF file. d For compounds 10 and
11, C2 and C3 correspond to C3 and C4 and to C4 and C5, respectively.
Figure 5. The 2-D architecture generated by conformer 30 via Cl H HBs in the polymorph 3. The encapsulation of THF molecules via further HBs is
shown.
3 3 3

966 Inorganic Chemistry, Vol. 49, No. 3, 2010
Vargas-Pineda et al.
Figure 6. The chain motif formed in the polymorph 3B along the c direction via H π interactions with the methyl and methylene group.
3 3 3
Figure 7. The chain motif parallel to the c direction found in the crystal structure of 6 formed by H π bonds. The chain is interlinked to others via
3 3 3
H
Cl bonds not shown for clarity.
3 3 3
As noted in Figure 1, the major difference between the
conformers 30 and 300 is the orientation of the aromatic
rings: in the case of 30 they have a tilt angle of only
7.65(20)° because there is a π-π interaction between
them, while in 300 the tilt angle is 111.82(11)°, an unusual
distinction within a single molecular species.
In the polymorph 3, the conformer 30 generates a 2-D
network (Figure 5) in the plane [001] via hydrogen bonds
(HBs), with the chlorine atoms acting as acceptors [HB1,
˚
r(H5 Cl1) = 2.90 A]. The THF molecule occupies the
3 3 3
cavities left in the 2-D framework of 30, and it is fixed in
them by two HBs. [The complementary geometrical
parameters for each HB are listed together with the
symmetry operations used to generate the equivalent
atoms in Table S1 in the Supporting Information.] The
first one is a bifurcated HB symmetrically equivalent to
O1S (S = solvent) toward the methyl group of two 30
molecules [HB2, r(H8C O1S) = 2.81 A]; the second
one is a HB donor to the methoxy oxygen [HB3,
˚
r(H1SB O1) = 2.76 A], and in total these interactions
generate a chain motif in the a direction that reinforces
the 2D network (Figure 5).
˚
3 3 3
3 3 3
There is a second motif which is responsible for the 3D
nature of the crystal structure; this new motif is a chain,
Figure 8. Segment of the chain of 10 with the two equivalent contacts
Cl Sn. The H π interaction is not shown here for simplicity.
3 3 3
3 3 3
( THF 300
30
300 )n , formed by Cl H interac-
3 3 3 3 3 3 3 3 3 3 3
3
3
3 3 3
tions with conformer 300 above and below the 2-D network
and other systems,12 where it has been argued that ionic
contributions to the higher coordination numbers pre-
dominate over any covalent contributions.11d Similar
behavior is common to related tin compounds with
intramolecular contacts, for example, dichloro-bis(2,6-
bis(tbutoxymethyl)phenyl)-tin(IV),10 dibromo-bis(1,2-
diethoxycarbonyl-ethyl)-tin(IV),13 and bis(2-carboethoxy-
ethyl)-diiodo-tin(IV).14
˚
˚
[HB4,r(H13 Cl1) = 2.89 A;HB5,r(H7 Cl2) = 2.69 A]
3 3 3
3 3 3
and to THF molecules from 300 [HB6, r(H1SA Cl1) =
3 3 3
˚
2.84 A]. Additionally, two intermolecular H πinteractions
3 3 3
are noted,15 which add force to the crystal structure just
described, forming an helicoidal chain motif in the c direction
[HB7, r(H8A RC2) = 2.66; HB8, r(RC2 H16B) =
3 3 3
3 3 3
˚
2.74 A].
In the crystal structure of the polymorph 3a, the archi-
tecture described for 3 is lost, because only 300 is present.
(12) (a) King, R. B. J. Organomet. Chem. 2001, 623, 95–100. (b) Hoffmann,
R.; Howell, J. M.; Rossi, A. R. J. Am. Chem. Soc. 1976, 98, 2484–2492. (c)
Wong, Y.-L.; Yang, Q.; Zhou, Z.-Y.; Lee, H. K.; Mak, T. C. W.; Ng, D. K. P. New
J. Chem. 2001, 25, 353–357. (c) Kubacek, P.; Hoffmann, R. J. Am. Chem. Soc.
1981, 103, 4320–4332.
(13) Kimura, T.; Ueki, T.; Yasuoka, N.; Kasai, N.; Kakudo, M. Bull.
Chem. Soc. Jpn. 1969, 42, 2479–2485.
(14) Howie, R. A.; Wardell, S. M. S. V. Acta Crystallogr. 2002, E58,
m257–m259.
Now, 300 forms chains along the c direction through H
bonds of the side-on-side type involving the methylene and
π
3 3 3
˚
RC2) = 2.77 A; HB10,
the methyl groups [HB9, r(H1B
3 3 3
(15) Zukerman-Schpector, J.; Abu Affan, M.; Foo, S. W.; Tiekink, E. R.
T. Acta Crystallogr., Sect. E 2009, E65, o2951. (b) Dakternieks, D.; Zobel, B.;
Tiekink, E. R. T. App. Organomet. Chem. 2003, 17, 77–78.

Article
Inorganic Chemistry, Vol. 49, No. 3, 2010 967
Figure 9. Crystal packing of 10 along the b axis with the HBs formed by the oxygen displaying zigzag layers linked by HB with the aromatic hydrogens.
11) exhibit neither intra- nor intermolecular Sn
secondary bonding. Indeed the meta compound 10 is
O
3 3 3
isostructural with 1216 and exhibits two equivalent Sn-Cl
˚
bonds (2.364 A) and two equivalent Cl Sn intermole-
3 3 3
˚
cular contacts of 3.816 A (97.3% of the ΣvdW radii of Sn
and Cl), generating a typical chlorine-bridged polymeric
structural arrangement (Figure 8). These intermolecular
interactions are long and seem to have no effect on the
coordination geometry at Sn, which is tetrahedral for 10
and for the following structures which bear the same
structural arrangement: (ClCH2)2SnCl2,17 dichloro-bis-
(2-fluorobenzyl)-tin,18 and bis(p-chlorobenzyl)-dichloro-
tin.19 Whether this structural arrangement is due to
packing features or to dipolar interactions is presently
an open question. Although no O Sn interaction is
present in the structure, the O atom contributes to the
3 3 3
crystal structure via two HBs, [HB18, r(O1 H8A) =
3 3 3
˚
˚
2.60 A; HB19 r(Ol H6) = 2.78 A], with an angle of 92°
Figure 10. The chain generated by Cl Sn interactions in the crystal
3 3 3
3 3 3
structure of 11. Only the heavy atoms are labeled; the rest of the atoms
are omitted for clarity.
between them. HB18 links identical enantiomers, thereby
generating zigzag layers along the ab plane [001], and
HB19 interconnects these chains (Figure 9).
In the crystal structure of 10, the aromatic rings are
arranged head-to-head on the same plane, generating un-
favorable interactions between the methyl hydrogens and the
˚
r(RC10 H16C) = 2.81 A], Figure 6. These chains are
interlinked by Cl H interactions which are longer than in
3 3 3
3 3 3
˚
3 [HB11, r(H6 Cl1) = 3.04 A; HB12, r(H14 Cl2) =
3 3 3
3 3 3
˚
˚
= 2.99 A; HB14,
20
˚
3.03 A; HB13, r(H8 CCl2)
p-hydrogen [r(H C8)=2.97 A). A search in the CSD
revealed three other crystal structures of phenols that bear
this kind of unfavorable interaction: 2-((3-methoxyphenyl)-
3 3 3
3 3 3
˚
r(H12 Cl2) = 2.85 A].
3 3 3
For the sulfur analog 6 (Figure 2), the distance Sn S,
3 3 3
21
ethynyl)-6-0methylpyridine (3.36 A), 1,10-bis(3-methoxy-
˚
3.029(1), is 76.5% of the ΣvdW radii, and the coordination
geometry around the tin atom in 6 is again a bicapped
tetrahedral, 76% character, similar to 300. The structure is
different from that of both conformers of 3 (Figure 1): the
dihedral angle C2-C1-C1A-C2A is 179.86°, while in 300 it
is -103°, and the crystal structure consists of a chain along
22
˚
benzyl)-3,3 -methylene-di-imidazolium dibromide (2.97 A),
23
and 3-methoxyphenylsalicyladimine (3.05 A), which is
˚
(16) Li, K.-Z.; Yin, H.-D. Huaxue Shiji 2005, 27, 139–140.
(17) Veith, M.; Agustin, D.; Huch, V. J. Organomet. Chem. 2002, 646,
138–145.
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(19) Kuang, D.-Z.; Feng, Y.-L. Wuji Huaxue Xuebao 2000, 16, 603–606.
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the c direction (Figure 7) formed by H π [HB15,
3 3 3
˚
r(H1A RC2) = 2.87 A] interlinked by means of Cl
H
bonds [HB16, r(Cl1 H4) = 2.89 A; HB17, r(Cl1 H6) =
3 3 3
3 3 3
˚
3 3 3
3 3 3
˚
2.83 A]. The differences observed in the conformation and the
crystal structure of 6 with repect to 3 is a consequence of
having the methyl group out of the aromatic plane.
In contrast to the crystal structures of 6 and 3, the meta-
and para-(MeOC6H4)CH2]2SnCl2 compounds (10 and

968 Inorganic Chemistry, Vol. 49, No. 3, 2010
Vargas-Pineda et al.
Figure 11. The secondary chain motif generated in the crystal structure of 11, beside the Sn Cl chain (omitted for clarity) through HB20, which is
coplanar with the aromatic rings. The hanging contacts are the second HB that binds the chains.
3 3 3
overridden by the cooperative effect of the noncovalent
interactions.
intramolecular O(S) Sn interactions, resulting in the
3 3 3
formation of monomeric bicapped tetrahedral structures
at tin with no intermolecular bridging chlorine interac-
tions. Although weak, as determined by internuclear
The structure of 11 has a conformation similar to that
of 10; however, the methyl groups are orientated toward
the same side, resulting in a slight difference between the
angles Cl1-Sn1-C1 [110.25(08)°] and Cl2-Sn1-C1
[104.86(15)°]. The coordination geometry at Sn is mono-
capped tetrahedral against the tetrahedral geometry
described above for 10. The crystal structure is also
O(S) Sn distances and geometric parameters at tin,
3 3 3
the interactions are sufficiently strong to persist in solu-
tion as determined by 119Sn NMR spectroscopy. The
related isomeric meta- and para-MeO-substituted com-
pounds exhibit neither inter- nor intramolecular O Sn
interactions and form polymeric structures involving
3 3 3
different from 10 since the contacts Cl Sn are inequi-
3 3 3
˚
valent, with one larger than the ΣvdW radii (3.943 A) and
bridging Cl Sn linkages.
3 3 3
˚
the other 89.3% of the ΣvdW radii (3.502 A), suggesting
that only the second one is important, forming the major
chain motif (Figure 10). Besides this interaction, two HBs
with the methyl groups are formed; the first one is co-
Acknowledgment. This research was supported by
grants from the Welch Foundation, Houston, Texas
(Grant AH-0546), and the NIH-SCORE program
(Grant GM-08012). The authors also wish to thank the
Kresge Foundation for funds that helped purchase, and
help upkeep, our NMR facility.
planar with the aromatic ring [HB20, r(O1 H8A) =
3 3 3
˚
2.68 A] generating a secondary chain motif (Figure 11),
which is interconnected, through HB21 [r(O1 H8C) =
3 3 3
˚
2.72 A]. Then, the expansion of the crystal structure is
done by oxygen-methyl group HBs as in 10.
Supporting Information Available: CIF files giving crystallo-
graphic data for 3, 6, 10, and 11 together with a table contain-
ing the complementary geometrical parameters for each HB
together with the symmetry operations used to generate the
equivalent atoms. These data can be obtained free of charge via
the Internet at http://pubs.acs.org.
In summary, we have synthesized bis-benzyltindichlor-
ide compounds with MeO-, MeS-, MeCH2-, and H-
ortho substituents that clearly illustrate that a significant
structural change occurs in the presence of the two Lewis
base groups MeO- and MeS. The change results in