Reaction of butyltin hydroxide oxide with p-toluenesulfonic acid: Synthesis, X-ray crystal analysis, and multinuclear NMR characterization of {(BuSn)12O14(OH)6}(4-CH3C 6H4SO3)2

Article abstract of DOI:10.1021/om990877a

The reaction of butyltin hydroxide oxide, BuSnO(OH), with p-toluenesulfonic acid, 4-CH₃C₆H₄SO₃H, yields the butyltin oxo cluster {(BuSn)₁₂(μ₃-O)₁₄(μ₂-OH) ₆}²⁺ mixed with a soluble ill-defined butyltin oxo polymer, the presence of which was established by solid-state and quantitative solution ¹¹⁹Sn NMR. The reaction conditions were varied in order to optimize the yield of oxo cluster, which can be quantitatively isolated by crystallization as {(BuSn)₁₂O₁₄(OH)₆}(4-CH₃C ₆H₄SO₃)₂·C₄H ₈O₂ (1·diox). The structure of the latter compound was determined by X-ray diffraction. 1·diox and {(BuSn)₁₂O₁₄(OH)₆}-(4-CH₃C ₆H₄SO₃)₂ (1) were also characterized by solid-state ¹¹⁹Sn MAS NMR and solution ¹¹⁹Sn, ¹H, and ¹³C NMR. In 1·diox, the existence of weak Lewis interactions, taking place in the crystal between five-coordinate tin atoms and dioxane molecules, was evidenced by solid-state ¹¹⁹Sn NMR. 2D ¹H-¹H NOESY and ROESY experiments, along with ionic conductivity measurements, have proved that the ionic dissociation between {(BuSn)₁₂O₁₄(OH)₆}²⁺ and 4-CH₃C₆H₄SO₃^- (PTS^-) does not take place in dichloromethane, while it does in the more polar and dissociating dimethyl sulfoxide. Using the ¹H-¹¹⁹Sn J-HMQC NMR technique, the weak ²J(¹H-O-¹¹⁹Sn) coupling constant between the μ₂-OH and the six-coordinate tin nuclei was determined and shown to depend on the solvent.

Full text of DOI:10.1021/om990877a

1940
Organometallics 2000, 19, 1940-1949
Rea ction of Bu tyltin Hyd r oxid e Oxid e w ith
p-Tolu en esu lfon ic Acid : Syn th esis, X-r a y Cr ysta l
An a lysis, a n d Mu ltin u clea r NMR Ch a r a cter iza tion of
{(Bu Sn )12O14(OH)6}(4-CH3C6H4SO3)2
Christophe Eychenne-Baron, Franc¸ois Ribot,* Nathalie Steunou, and
Cle´ment Sanchez
Laboratoire de Chimie de la Matie`re Condense´e, UMR CNRS 7574, Tour 54, 5e e´tage,
Universite´ Pierre et Marie Curie, 4 Place J ussieu, F-75252 Paris Cedex 05, France
Franck Fayon
Centre de Recherche sur les Mate´riaux a` Haute Tempe´rature, UPR CNRS 4212, 1D avenue de
la Recherche Scientifique, F-45071 Orle´ans Cedex 2, France
Monique Biesemans, J ose´ C. Martins, and Rudolph Willem
High-Resolution NMR Center (HNMR), Free University of Brussels (VUB), Pleinlaan 2,
B-1050 Brussels, Belgium
Received November 2, 1999
The reaction of butyltin hydroxide oxide, BuSnO(OH), with p-toluenesulfonic acid,
4-CH3C6H4SO3H, yields the butyltin oxo cluster {(BuSn)12(µ3-O)14(µ2-OH)6}2+ mixed with a
soluble ill-defined butyltin oxo polymer, the presence of which was established by solid-
state and quantitative solution 119Sn NMR. The reaction conditions were varied in order to
optimize the yield of oxo cluster, which can be quantitatively isolated by crystallization as
{(BuSn)12O14(OH)6}(4-CH3C6H4SO3)2‚C4H8O2 (1‚diox). The structure of the latter compound
was determined by X-ray diffraction. 1‚diox and {(BuSn)12O14(OH)6}(4-CH3C6H4SO3)2 (1) were
1
also characterized by solid-state 119Sn MAS NMR and solution 119Sn, H, and 13C NMR. In
1‚diox, the existence of weak Lewis interactions, taking place in the crystal between five-
coordinate tin atoms and dioxane molecules, was evidenced by solid-state 119Sn NMR.
1
2D H-1H NOESY and ROESY experiments, along with ionic conductivity measurements,
-
have proved that the ionic dissociation between {(BuSn)12O14(OH)6}2+ and 4-CH3C6H4SO3
(PTS-) does not take place in dichloromethane, while it does in the more polar and
dissociating dimethyl sulfoxide. Using the H-119Sn J -HMQC NMR technique, the weak
1
2J (1H-O-119Sn) coupling constant between the µ2-OH and the six-coordinate tin nuclei was
determined and shown to depend on the solvent.
In tr od u ction
starting Sn/acid ratio and the nature of the acid control
the outcome of these syntheses. Other monorganotin
oxo clusters, without complexing ligands bound to tin
Several structures of monoorganotin oxo clusters have
been shown to be versatile nanobuilding blocks for the
design of tin-based hybrid organic-inorganic materials.1
Many of these oxo clusters contain strongly complexing
ligands such as carboxylates (i.e., [PhSnO(O2CC6H11)]6),2
phosphinates (i.e., {[BuSn(OH)(O2PPh2)]3O}(O2PPh2)),3
and phosphates (i.e., [BuSnO(O2P(OPh)2)]6),4 which
cover the oxo cores and generally allow hexacoordination
for tin. They are usually synthesized from organo-
stannonic acids and the corresponding carboxylic- or
phosphorus-based acids in a nonpolar solvent.5 The
6
(i.e., (PriSn)9O8(OH)6Cl5 or {(PriSn)12O14(OH)6}Cl2),7
are also known. All of these have been prepared, some-
times with very low yields, by hydrolysis-condensation
of molecular monoorganotin compounds (RSnCl3,6-8
RSn(OR′)3,9 or RSn(CtCR′)310). However, we have
recently shown that the reaction of sulfonic acid with
butylstannonic acid, BuSnO(OH), is a cheap and easy
alternative to prepare the macrocation {(BuSn)12O14-
(OH)6}2+ 11
.
(5) Holmes, R. R. Acc. Chem. Res. 1989, 22, 190.
(6) Puff, H.; Reuter, H. J . Organomet. Chem. 1989, 368, 173.
(7) Puff, H.; Reuter, H. J . Organomet. Chem. 1989, 373, 173.
(8) Dakternieks, D.; Zhu, H.; Tiekink, E. R. T.; Colton, R. J . J .
Organomet. Chem. 1994, 476, 33.
(9) Banse, F.; Ribot, F.; Tole´dano, P.; Maquet, J .; Sanchez, C. Inorg.
Chem. 1995, 34, 6371.
* To whom correspondence should be addressed. E-mail: fri@
ccr.jussieu.fr.
(1) Ribot, F.; Eychenne-Baron, C.; Sanchez, C. Phosphorus, Sulfur
Silicon Relat. Elem. 1999, 150-151, 41.
(2) Chandrasekhar, V.; Day, R. O.; Holmes, R. R. Inorg. Chem. 1985,
24, 1970.
(3) Day, R. O.; Holmes, J . M.; Chandrasekhar, V.; Holmes, R. R. J .
Am. Chem. Soc. 1987, 109, 940.
(4) Day, R. O.; Chandrasekhar, V.; Kumara Swamy, K. C.; Holmes,
J . M.; Burton, S. D.; Holmes, R. R. Inorg. Chem. 1988, 27, 2887.
(10) J aumier, P.; J ousseaume, B.; Lahcini, M.; Ribot, F.; Sanchez,
C. J . Chem. Soc., Chem. Commun. 1998, 369.
(11) Eychenne-Baron, C.; Ribot, F.; Sanchez, C. J . Organomet. Chem.
1998, 567, 137.
10.1021/om990877a CCC: $19.00 © 2000 American Chemical Society
Publication on Web 04/14/2000

Tin-Based Organic-Inorganic Materials
Organometallics, Vol. 19, No. 10, 2000 1941
F igu r e 2. Packing diagram for {(BuSn)12O14(OH)6}(4-
CH3C6H4SO3)2‚C4H8O2 (1‚diox), showing the “cation-
anion” chains (parallel to [100]) and their arrangement into
planes (parallel to [110]).
metric counterparts). Six hydroxy groups bridge the six-
coordinate tin atoms pairwise and define the cage poles.
Two p-toluenesulfonate counteranions interact with
the cage poles. A framework of hydrogen bonds, char-
acterized by an average O-O distance of 2.74 Å, links
the oxo clusters into chains parallel to the a axis of the
structure (Figure 2). This framework involves one-to-
one contacts between the three oxygen atoms of both
sulfonate anions (O45X, O46X, O56X, and their sym-
metric counterparts) and all six µ2-OH bridges. The
formation of chains due to counteranions bridging two
macrocations is common for the {(BuSn)12O14(OH)6}2+
cluster, yet 1‚diox is the first where all the bridging
hydroxy groups are in contact with the anions.8,9 This
feature is in line with the almost identical environments
of the six-coordinate tin atoms (Table 1), in contrast with
the other structures, where two main six-coordinate
environments are identified.8,9
The oxygen atoms of a 1,4-dioxane molecule (O1, C1A,
C1B, and their symmetric counterparts) form weak
donor-acceptor interactions (d(Sn-O) ≈ 3.3 Å) with
four five-coordinate tin atoms (Sn2, Sn3, and their
symmetric counterparts). These contacts cause a small
displacement of the R-carbons (C20, C30, and their
symmetric counterparts), as evidenced by the O-Sn-C
angles (Table 1), and connect “cation-anion” chains into
planes parallel to the a and b axes (Figure 2). This type
of interaction is unreported, since in all structures
described so far, the solvating molecules (DMF,7 H2O,8
HOPri 9) were always hydrogen-bound to bridging hy-
droxy groups not interacting with the anions.
F igu r e 1. CAMERON31 drawing of {(BuSn)12O14(OH)6}-
(4-CH3C6H4SO3)2‚C4H8O2 (1‚diox), showing 20% displace-
ment ellipsoids (two dioxane molecules have been repre-
sented, but only the R-carbon of the butyl chains has been
drawn for clarity).
This paper reports on the reaction between BuSnO-
(OH) and 4-CH3C6H4SO3H (HPTS), with different nomi-
nal tin-to-sulfur ratios (Sn/S varying from 12/2 to
12/8). The crystallographic structure of {(BuSn)12O14-
(OH)6}(4-CH3C6H4SO3)2‚C4H8O2 (1‚diox; diox ) diox-
ane), as determined from single-crystal X-ray diffrac-
tion, as well as solid- and solution-state multinuclear
NMR charaterizations of 1 and 1‚diox, are presented.
The interactions between {(BuSn)12O14(OH)6}2+ and
4-CH3C6H4SO3 (PTS-) in solution were investigated.
-
Resu lts a n d Discu ssion
X-r a y Diffr a ction Str u ctu r e of 1‚d iox. The molec-
ular structure and a packing diagram of 1‚diox are pre-
sented in Figures 1 and 2, respectively. Selected inter-
atomic distances and bond angles are given in Table 1.
The main component of this centrosymmetric compound
is the {(RSn)12(µ3-O)14(µ2-OH)6}2+ macrocation.7-9
As previously reported,7-9 it is composed of twelve tin
atoms bound to one butyl group and linked by µ3-O
(O125, O126, O134, O135, O234, O236, O456, and their
symmetric counterparts) and µ2-OH bridges (O45, O46,
O56, and their symmetric counterparts). The six five-
coordinate tin atoms exhibit a square-pyramidal envi-
ronment (Sn1, Sn2, Sn3 and their symmetric), while the
other six tin atoms exhibit a six-coordinate distorted-
octahedral geometry (Sn4, Sn5, Sn6, and their sym-
Th er m a l Beh a vior of 1‚d iox. The thermogravi-
metric and differential thermal analyses of 1‚diox
(Figure 3) reveal four weight losses between 20 and 1000
°C. The final product corresponds to SnO2 (cassiterite),12
as revealed by X-ray powder diffraction, and the total
weight loss indicates a dioxane-deficient composition
close to {(BuSn)12O14(OH)6}(PTS)2(C4H8O2)0.4 (exptl,
35.7%; calcd, 35.7%). The first weight loss (85 °C; weakly
endothermic) corresponds to leaving dioxane and agrees
well with the lack of dioxane (exptl, 1.2%; calcd, 1.2%).
(12) McCarthy, G.; Welton, J . Powder Diffr. 1989, 4, 156.

1942 Organometallics, Vol. 19, No. 10, 2000
Eychenne-Baron et al.
Ta ble 1. Selected In ter a tom ic Dista n ces (Å) a n d Bon d An gles (d eg) for
{(Bu Sn )12O14(OH)6}(4-CH3C6H4SO3)2‚C4H8O2 (1‚d iox) w ith Esd ’s in P a r en th esesa
b
Sn p -O
2.087
Sn p -O
2.027
Sn h -O
2.115
Sn1-O125
Sn1-O135
Sn2-O126
Sn2-O236
Sn3-O134′
Sn3-O234′
Sn h -O
Sn4-O456
Sn5-O456
Sn6-O456
O-H‚‚‚O
O45-O45X
O46-O46X′′
O56-O56X′′
Sn p ‚‚‚Sn p
Sn1-Sn2
Sn1-Sn3′
Sn2-Sn3
2.071(5)
2.094(5)
2.100(5)
2.091(5)
2.102(5)
2.065(5)
2.080
2.087(5)
2.082(5)
2.071(5)
2.74
Sn1-O134
Sn1-O126
Sn2-O125
Sn2-O234′
Sn3-O135′
Sn3-O236
Sn h -OH
Sn4-O46
Sn4-O45
Sn5-O45
Sn5-O56
Sn6-O46
Sn6-O56
2.020(5)
2.026(5)
2.043(5)
2.023(5)
2.026(5)
2.023(5)
2.120
2.127(5)
2.111(5)
2.113(5)
2.116(6)
2.116(5)
2.132(5)
Sn4-O134
Sn4-O234
Sn5-O125′
Sn5-O135′
Sn6-O126
Sn6-O236
Sn p -C
Sn1-C10
Sn2-C20
Sn3-C30
Sn h-C
2.115(5)
2.126(5)
2.097(5)
2.116(5)
2.113(5)
2.123(5)
2.121
2.135(9)
2.100(8)
2.127(8)
2.128
2.122(9)
2.136(8)
2.127(8)
3.294
3.2875(8)
3.2969(8)
3.2980(8)
3.30
2.805(9)
2.707(9)
2.71(1)
Sn4-C40
Sn5-C50
Sn6-C60
Sn h ‚‚‚Sn h
Sn4-Sn5
Sn4-Sn6
Sn5-Sn6
Sn p ‚‚‚Od iox
Sn2-O1
3.208
Sn p ‚‚‚Sn h
Sn1-Sn4
Sn1-Sn6
Sn2-Sn4′
Sn2-Sn5′
Sn3-Sn5
Sn3-Sn6
3.826
3.2208(8)
3.2132(8)
3.1915(8)
3.294
3.2757(8)
3.3049(8)
3.3027(8)
3.8085(8)
3.8029(8)
3.8323(8)
3.8385(8)
3.8436(8)
3.8307(8)
Sn p ‚‚‚Sn h
Sn1-Sn5′
Sn2-Sn6
3.244(6)
3.356(6)
1.449
Sn3-O1
S-O
Sn3-Sn4′
S1-C70
O1-C1A
O1-C1B
1.761(9)
1.44(1)
1.42(1)
S1-O45X
S1-O46X
S1-O56X
1.437(7)
1.454(8)
1.455(8)
O-Sn h -OH
91.2
O-Sn h -OH
76.4
76.1(2)
O-Sn p -C
111.1
HO-Sn h -C
c
97.8
c
O134-Sn4-O46
O234-Sn4-O45
O125′-Sn5-O45
O135′-Sn5-O56
O126-Sn6-O46
O236-Sn6-O56
c
c
90.9(2)
92.2(2)
92.2(2)
90.2(2)
91.3(2)
90.7(2)
76.1
75.6(2)
76.5(2)
76.1(2)
87.7
87.6(2)
88.1(2)
87.5(2)
87.2(2)
88.0(2)
88.1(2)
77.4
77.5(2)
77.6(2)
77.6(2)
76.6(2)
77.1(2)
77.4(2)
77.2(2)
77.2(2)
78.1(2)
O456-Sn4-O46
O456-Sn4-O45
O456-Sn5-O45
O456-Sn5-O56
O456-Sn6-O46
O456-Sn6-O56
HO-Sn h -OH
O125-Sn1-C10
O135-Sn1-C10
O134-Sn1-C10
O126-Sn1-C10
O125-Sn2-C20
O126-Sn2-C20
O236-Sn2-C20
O234′-Sn2-C20
O135′-Sn3-C30
O134′-Sn3-C30
O236-Sn3-C30
O234′-Sn3-C30
109.5(3)
109.4(3)
112.0(3)
111.6(3)
104.3(3)
105.9(3)
118.8(3)
118.8(3)
105.7(3)
106.8(3)
116.9(3)
116.9(3)
O46-Sn4-C40
O45-Sn4-C40
O45-Sn5-C50
O56-Sn5-C50
O46-Sn6-C60
O56-Sn6-C60
96.8(3)
96.6(3)
98.0(3)
99.2(2)
99.1(3)
97.2(3)
99.1
100.6(3)
100.4(3)
98.0(3)
99.0(3)
99.4(3)
97.4(2)
102.5
103.1(2)
102.5(2)
102.4(2)
102.6(2)
101.7(2)
102.6(2)
135.0
136.0(3)
136.2(3)
134.1(3)
133.5(3)
135.0(2)
135.0(3)
102.0
76.5(2)
76.6(2)
76.4(2)
76.7(2)
76.3(2)
96.4
96.3(2)
96.0(2)
97.0(2)
160.2
159.7(2)
160.4(2)
160.7(2)
159.7(2)
159.9(2)
160.8(2)
96.7
98.1(2)
96.0(2)
95.9(2)
135.6
O-Sn h -O
O-Sn h -C
c
c
c
O134-Sn4-O234
O125′-Sn5-O135′
O126-Sn6-O236
O46-Sn4-O45
O45-Sn5-O56
O46-Sn6-O56
O134-Sn4-C40
O234-Sn4-C40
O125′-Sn5-C50
O135′-Sn5-C50
O126-Sn6-C60
O236-Sn6-C60
Sn p -O-Sn p
O-Sn h -O
O-Sn h -OH
c
t
O134-Sn4-O456
O234-Sn4-O456
O125′-Sn5-O456
O135′-Sn5-O456
O126-Sn6-O456
O234-Sn4-O46
O134-Sn4-O45
O135′-Sn5-O45
O125′-Sn5-O56
O126-Sn6-O56
O236-Sn6-O46
O-Sn h -C
171.1
t
O456-Sn4-C40
O456-Sn5-C50
O456-Sn6-C60
169.3(3)
172.5(3)
171.6(3)
Sn1-O125-Sn2
Sn1-O135-Sn3′
Sn1-O134-Sn3′
Sn1-O126-Sn2
Sn2-O236-Sn3
Sn2′-O234-Sn3′
Sn p -O-Sn h
Sn2-O125-Sn5′
Sn3′-O135-Sn5′
Sn1-O134-Sn4
Sn1-O126-Sn6
Sn3-O236-Sn6
Sn2′-O234-Sn4
Sn h -OH-Sn h
Sn4-O46 -Sn6
Sn4-O45-Sn5
Sn5-O56-Sn6
O-S-C
O236-Sn6-O456
b
O-Sn p -O
O-Sn p -O
c
c
O125-Sn1-O135
O135-Sn1-O134
O125-Sn1-O126
O125-Sn2-O126
O126-Sn2-O236
O236-Sn2-O234′
O135′-Sn3-O134′
O134′-Sn3-O234′
O236-Sn3-O234′
O134-Sn1-O126
O125-Sn2-O234′
O135′-Sn3-O236
Sn p -O-Sn h
103.2
O-Sn p -O
Sn1-O125-Sn5′
Sn1-O135-Sn5′
Sn3′-O134-Sn4
Sn2-O126-Sn6
Sn2-O236-Sn6
Sn3′-O234-Sn4
Sn h -O-Sn h
103.1(2)
102.2(2)
103.1(2)
103.4(2)
103.3(2)
104.0(2)
104.7
104.9(2)
104.1(2)
105.1(2)
113.0
t
O135-Sn1-O126
O125-Sn1-O134
O125-Sn2-O236
O126-Sn2-O234′
O134′-Sn3-O236
O135′-Sn3-O234′
137.2(2)
136.7(2)
134.1(2)
135.0(2)
135.9(2)
135.0(2)
Sn4-O456 -Sn6
Sn4-O456-Sn5
Sn5-O456 -Sn6
O-S-O
102.0(2)
102.2(2)
101.9(2)
105.6
O45X-S1-O46X
O45X-S1-O56X
O46X-S1-O56X
111.1(5)
113.9(1)
114.0(4)
O45X-S1-C70
O46X-S1-C70
O56X-S1-C70
106.1(4)
104.9(5)
105.9(5)
a
Legend: subscripts p and h refer to five and six-coordinate tin atoms, respectively; ′ refers to the symmetry -x, -y, -z; ′′ refers to the
b
symmetry 1 - x, -y, -z; subscripts c and t refer to cis and trans positions, respectively. Bond distances and angles in broken brackets
denote average values.
This loss of dioxane upon aging appears unavoidable.
After the first weight loss, the compound, stable up
to 250 °C, is identified as 1, {(BuSn)12O14(OH)6}(4-
CH3C6H4SO3)2, by 119Sn NMR (vide infra) and elemental
analyses. The three subsequent weight losses (∼290 °C,
strongly exothermic; ∼400 °C, strongly exothermic;
between 600 and 900 °C, weakly exothermic) cannot be
assigned. The one around 290 °C likely involves com-
bustion of butyl chains, since BuSnO(OH)13 and other
{(BuSn)12O14(OH)6}X2 compounds (X ) OH-, OAc-)
decompose around the same temperature.
Solid -Sta te 119Sn MAS NMR Stu d ies of 1‚d iox
a n d 1. Figure 4 presents the 119Sn MAS NMR spectra
(13) Blunden, S. J .; Hill, R.; Suton, S. E. Appl. Organomet. Chem.
1991, 5, 159.

Tin-Based Organic-Inorganic Materials
Organometallics, Vol. 19, No. 10, 2000 1943
Ta ble 2. 119Sn MAS NMR Da ta a
δiso
,
ú,
ppm
σ11
,
σ22
,
σ33,
signal ppm
η
ppm ppm ppm intensb coord
{(BuSn)12O14(OH)6}(4-CH3C6H4SO3)2‚C4H8O2 (1‚diox)
A
B
C
D
E
F
-283.9
3.4
1.4
1.3
2.5
2.2
1.3
5
-300.3 398.2 0.20 62.3 141.0 698.6
5 + 1
5 + 1
6
6
6
-306.9 434.4 0.25 35.4 144.0 741.3
-462.0
-466.3
-469.3
{(BuSn)12O14(OH)6}(4-CH3C6H4SO3)2 (1)
X
Y
Z
-283.9 386.2 0.20 52.2 129.4 670.1
-461.7 313.8 0.30 257.7 351.9 775.5
-467.4 325.8 0.30 255.6 353.4 793.2
6.7
1.9
3.4
5
6
6
a
δiso ) -σiso ) -(σ11 + σ22 + σ33)/3, ú ) σ33 - σiso, and η ) |σ22
- σ11|/|σ33 - σiso|, where σ11, σ22, and σ33 are the principal
components of the 119Sn shielding tensor, ordered with the
b
following rule: |σ33 - σiso| g |σ11 - σiso| g |σ22 - σiso|. Intensities
have been normalized to 12 for each compound.
F igu r e 3. Simultaneous thermogravimetric (TGA) and
differential thermal (DTA) analyses of {(BuSn)12O14(OH)6}-
(4-CH3C6H4SO3)2‚C4H8O2 (1‚diox) at 10 °C/min and under
pure oxygen.
number of nonequivalent tin atoms in the X-ray struc-
ture. However, the quantification inside each coordina-
tion does not agree with the structure. This discrepancy
likely arises from a partial loss of dioxane, as for TGA,
which results in a sample made of a mixture of 1‚diox
and 1. Therefore, a precise assignment of the 119Sn NMR
resonances and the determination of the principal
components of the 119Sn shielding tensors14-16 are not
possible, except for the more shielded and equally
populated five-coordinate sites (B and C), which can be
assigned to Sn2 and Sn3. Indeed, they have additional
remote contacts with a dioxane oxygen and therefore
belong only to 1‚diox. The latter assignment is confirmed
by the disappearance of the low-frequency resonances
upon removing dioxane. A further assignment (Sn3 )
B and Sn2 ) C), based on the Sn-O1 distances, would
be too speculative.
The 119Sn MAS NMR spectrum of 1 (Figure 4b)
reveals only a single 119Sn signal for all six five-
coordinate tin atoms and two signals (-461.7 and
-467.4 ppm), roughly in a 2:4 ratio, for the six-
coordinate ones. This apparent C2v symmetry, upon
removing dioxane, is in line with the conservation of
the structure of {(BuSn)12O14(OH)6}(PTS)2 and results
from two sulfonate oxygens being close to Sn6 and a
single oxygen from another sulfonate unit being close
to Sn4 and Sn5. This allows a tentative assignment of
site Y (-461.7 ppm) to Sn6. The principal components
of the 119Sn shielding tensors14-16 of 1 are reported in
Table 2.
Solu tion NMR Stu d ies of 1‚d iox a n d 1. The
solution 119Sn{1H} NMR spectra of 1‚diox and 1 in CD2-
Cl2 are identical and are similar to spectra previously
reported for other {(BuSn)12O14(OH)6}2+-based com-
pounds.8,9,17,18 They consist of two concentration-inde-
pendent, sharp 119Sn resonances at -282.8 and -461.8
ppm, respectively assigned to the five- and six-coordi-
nate tin atoms. Each resonance is flanked by three sets
F igu r e 4. Experimental and simulated 119Sn MAS NMR
spectra of (a) {(BuSn)12O14(OH)6}(4-CH3C6H4SO3)2‚C4H8O2
(1‚diox) and (b) {(BuSn)12O14(OH)6}(4-CH3C6H4SO3)2 (1).
νMAS ) 13.5 kHz, and isotropic resonances are pointed with
arrows. In (a) the insert shows an expansion of the isotropic
resonances of the six-coordinate tin atoms.
2
of J (119Sn-O-119/117Sn) satellites, corresponding to a
of 1‚diox and 1. For both compounds, the isotropic
chemical shifts around -300 and -460 ppm are easily
assigned to five- and six-coordinate tin atoms, respec-
tively. The spectra were simulated in order to quantify
each site. Results are gathered in Table 2.
(14) Klaus, E.; Sebald, A. Magn. Reson. Chem. 1994, 32, 679.
(15) Harris, R. K.; Lawrence, S. E.; Oh, S. W. J . Mol. Struct. 1995,
347, 309.
(16) Ribot, F.; Sanchez, C.; Meddour, A.; Gielen, M.; Tiekink, E. R.
T.; Biesemans, M.; Willem, R. J . Organomet. Chem. 1998, 552, 177.
(17) Ribot, F.; Sanchez, C.; Willem, R.; Martins, J . C.; Biesemans,
M. Inorg. Chem. 1998, 37, 911.
For 1‚diox, the number of isotropic resonances, three
for each coordination type, is in agreement with the
(18) Ribot, F.; Banse, F.; Diter, F.; Sanchez, C. New J . Chem. 1995,
19, 1145.

1944 Organometallics, Vol. 19, No. 10, 2000
Eychenne-Baron et al.
a ,b
Ta ble 3. Solu tion NMR Da ta for {(Bu Sn )12O14(OH)6}(4-CH3C6H4SO3)2‚C4H8O2 (1‚d iox) in CD2Cl2
δ(1H), ppm
nJ (1H-119Sn)g, Hz
δ(13C), ppm
nJ (13C-119/117Sn), Hz
assignt
1.66 (t)h
101
126
160
125
21.7
27.2
27.0
28.0
26.2
26.5
13.5
13.8
860/820
1162/1114
51i
SnpCH2CH2CH2CH3
SnhCH2CH2CH2CH3
SnpCH2CH2CH2CH3
SnhCH2CH2CH2CH3
SnpCH2CH2CH2CH3
SnhCH2CH2CH2CH3
SnpCH2CH2CH2CH3
SnhCH2CH2CH2CH3
µ2-OH
1.27 (t)h
1.79 (quint)h
1.63 (quint)h
1.52 (sext)h
1.38 (sext)h
0.97 (t)h
54i
92i
163/155
0.91 (t)h
7.02 (s)h
1.05
j
140.6
126.0
128.3
141.7
21.2
ipso O3SC6H4CH3
ortho O3SC6H4CH3
meta O3SC6H4CH3
para O3SC6H4CH3
O3SC6H4CH3
7.69 (d)h
7.20 (d)h
2.37 (s)h
3.65 (s)h
67.2
C4H8O2
Chemical shifts referenced as in the Experimental Section. δ(Snp) -282.8 ppm [423/405,c 162,d 42e]; δ(Snh) -461.8 ppm [423/405,c
a
176,f 42e]. In solutions of ca. 50 mg of substance per 0.5 mL of solvent. 2J (119Snp-119/117Snh) or 2J (119Snh-119/117Snp) coupling
b
c
d
constant in Hz (single oxo bridge). 2J (119Snp-117Snp) coupling constant in Hz (double oxo bridge). e Unresolved 2J (119Snp-119/117Snh)
f
or 2J (119Snh-119/117Snp) coupling constant in Hz (double oxo bridge). 2J (119Snh-117Snh) coupling constant in Hz (double oxo-hydroxo
g
h
bridge). nJ (1H-119Sn) coupling constants, as determined from cross sections of the 2D 1H-119Sn HMQC spectrum. Multiplicity due to
i
j
nJ (1H-1H). Unresolved nJ (13C-119/117Sn). Measured through 1H-119Sn J -HMQC technique.
total of four different types of connectivity paths existing
between two tin atoms in {(BuSn)12O14(OH)6}2+, in
agreement with previous data.9 The 119Sn as well as the
1H and 13C NMR data are reported in Table 3.
The assignment of the butyl proton resonances to
their respective five- or six-coordinate tin atoms was
achieved by gradient-enhanced 1H-119Sn correlation
NMR spectroscopy, as described previously.17,19 Further
assignments were performed by comparison with re-
ported data and, in the case of 13C, also on the basis of
nJ (13C-119/117Sn) coupling constants.9,17
ity of the CD2Cl2 solution- and solid-state isotropic
119Sn chemical shifts, especially for the six-coordinate
tin atoms. Nuclear Overhauser effect spectroscopy
(NOESY)20 and rotating-frame nuclear Overhauser ef-
fect spectroscopy (ROESY)21 experiments have been
performed in order to evaluate the distance between the
macrocation and the counteranion as a function of the
solvent. In the 2D ROESY experiment, cross-peaks were
detected between proton resonances of the macrocation
(µ2-OH, R-, â-, and γ-CH2, and CH3 of the butyl chains
of the six-coordinate tin atoms) and the ortho proton
resonances of the PTS- anion, which unambiguously
proves their close proximity. Less relevant cross-peaks
within the macrocation and within the PTS- anion were
also observed. In 2D NOESY spectra (303 K), compari-
son of the signs of cross-peaks and diagonal peaks
revealed the same slow rotational tumbling regime for
the µ2-OH and the PTS- protons but a fast one for those
of the butyl chains (probably because of their confor-
mational freedom).20,21 Therefore, the distance separat-
ing the ortho PTS and the µ2-OH protons is the only
one for which a determination, using cross-peak volumes
derived from three ROESY experiments, is relevant (see
Experimental Section). This distance was estimated at
3.8 ( 0.1 Å, taking the ortho-meta proton distance (2.48
Å)22 as an internal reference. Globally, the main conclu-
sion is that, in CD2Cl2, a medium with low dielectric
constant, the p-toluenesulfonate anions remain in close
contact with the “poles” of the macrocation.
The identical solution 119Sn NMR spectra of 1‚diox
and 1, as well as the very good agreement between the
solution chemical shifts and the solid-state isotropic
shifts for 1, indicate that the Lewis interaction between
five-coordinate tin atoms and dioxane in the solid state
is completely lost when 1‚diox is dissolved. This inte-
action is therefore fairly weak in the solid state (even if
it is detectable by 119Sn MAS NMR) and is likely only
due to packing. The weakness of this interaction is
stressed by the 119Sn NMR chemical shifts of compound
1 in pure dioxane (diox/Sn ) 12) which display no
significant effect for both coordinations. A Lewis inter-
action between five-coordinate tin atoms and DMSO is
reported for {(BuSn)12O14(OH)6}(O2PPh2)2 in CD2Cl2/
DMSO (1/1 v/v), the 119Sn chemical shift of the five-
coordinate tin atoms being low-frequency-shifted by 25
ppm.17 In contrast, compound 1 does not interact
significantly with DMSO, since its concentration-
independent 119Sn chemical shift for five-coordinate
tin at -285.4 ppm remains unchanged. Thus, the
affinity of five-coordinate tin for Lewis bases in the
{(BuSn)12O14(OH)6}2+ macrocation depends on the
nature of the counteranion.
The ionic conductivity of 1 in CD2Cl2 was identical
with that of the pure solvent (ca. 5 µS cm-1), confirming
the absence of ionic dissociation. However, the bridging
mode between the macrocation and the sulfonates in the
solid state is most probably not maintained in solution.
Therefore, when 1 or 1‚diox is dissolved in CD2Cl2, each
The absence of ionic dissociation for {(BuSn)12O14-
(OH)6}X2 compounds in low dielectric constant solvents,
such as CD2Cl2 (ꢀ ) 8.9), has been recently evidenced
for {(BuSn)12O14(OH)6}(O2PPh2)2.17 For compound 1,
the strong contact between the cage poles and the
sulfonate anions still holds, as evidenced by the similar-
(20) (a) Neuhaus, D.; Williamson, M. P. The Nuclear Overhauser
Effect in Structural and Conformational Analysis; VCH: New York,
1989. (b) Cavanagh, J .; Fairbrother, W. J .; Palmer, A. G., III; Skelton,
N. J . Protein NMR Spectroscopy Principles and Practice; Academic
Press: San Diego, CA, 1996.
(21) (a) Bothner-By, A. A.; Stephens, R. L.; Lee, J .-M.; Warren, C.
D.; J eanloz, R. W. J . Am. Chem. Soc. 1984, 106, 811. (b) Bax, A.; Davis,
D. G. J . Magn. Reson. 1985, 63, 207.
(19) Willem, R.; Bouhdid, A.; Kayser, F.; Delmotte, A.; Gielen, M.;
Martins, J . C.; Biesemans, M.; Tiekink, E. R. T., Organometallics 1996,
15, 1920.
(22) The ortho-meta H-H distance was determined from a phenyl
moiety available in the Insight II builder fragment library (Insight II,
95.0, MSI Scranton Road, San Diego, CA).

Tin-Based Organic-Inorganic Materials
Organometallics, Vol. 19, No. 10, 2000 1945
sulfonate likely switches to a “terminal” position, with
its S-C bond along the macrocation 3-fold axis (passing
through O456 and its symmetric counterpart) and its
three oxygen atoms being hydrogen-bonded to the three
hydroxy groups of a single cage pole. This arrangement
does not break the D3d symmetry observed in solution
on the 119Sn NMR time scale, if it is reasonably assumed
that the aromatic ring freely rotates around the S-C
axis. This proposal is supported by the 119Sn chemical
shift of -461.8 ppm, which is nearly identical with the
isotropic chemical shift of site Y, assigned to Sn6, a six-
coordinate tin for which both hydroxy groups are
hydrogen-bonded to the same sulfonate moiety (vide
supra). Setting the distance between the protons of the
bridging hydroxy group and the ortho protons of PTS-
to 3.8 Å (ROESY experiment) results in the distance
between the oxygen of a bridging hydroxy group and
the oxygen of the sulfonate, which faces it, to be 2.5 Å,
in satisfactory agreement with the typical distance
separating two oxygen atoms in a strong hydrogen
bond.23
In DMSO-d6, the chemical shift of the six-coordinate
119Sn resonances moves to -473.5 ppm, for any concen-
tration from 2 × 10-3 to 2 × 10-1 mol/L. A similar low-
frequency shift was already observed for {(BuSn)12O14-
(OH)6}(O2PPh2)2 in CD2Cl2/DMSO (1/1 v/v) and cor-
related to an increase of the distance separating the
cage poles from the anions in a more polar medium.17
Indeed, 2D 1H-1H NOESY experiments in DMSO-d6 at
303 K reveal positive cross-peaks between the µ2-OH
and all the butyl protons but negative cross-peaks
between the protons within the anion PTS- and no
cross-peak at all between the µ2-OH and the ortho
aromatic protons of PTS-. This observation demon-
strates that the anion is tumbling faster than the
macrocation and, therefore, no longer has any tight
contact with it. Moreover, the absence of a cross-peak
between the cluster and anion protons also points to full
cation-anion dissociation. In DMSO-d6, which has a
higher viscosity than CD2Cl2, the butyl chains appear
to be less mobile. Control ROESY experiments all miss
the cross-peak between the µ2-OH and the ortho aro-
matic protons of PTS-, which proves that the lack of
cross-peak in the NOESY spectra is not due to an
unfortunate correlation time and strengthens the view
of full cation-anion dissociation in DMSO (ꢀ ) 46.7).
The conductivity values for 1 in DMSO range from
200 to 1210 µS cm-1 (pure solvent: 5.5 µS cm-1) for
concentrations of 5 × 10-3 to 5 × 10-2 mol/L, respec-
tively, in complete agreement with the cation-anion
dissociation proposed above.
For the first time for such {(BuSn)12O14(OH)6}2+
macrocations, the proton resonance around 7 ppm (7.02
ppm in CD2Cl2 and 7.33 ppm in DMSO-d6) displayed a
1H-119Sn HMQC correlation with the 119Sn resonance
of the six-coordinate tin atoms, none being observed for
the five-coordinate ones. This assigns this proton reso-
nance to the cage pole bridging µ2-OH hydroxy groups.
2
The J (1H-O-119Snh) coupling constant between the
µ2-OH hydroxy proton and the six-coordinate 119Sn
nuclei was determined by the J -HMQC technique.24
This technique which, to the best of our knowledge, has
not been described so far for 1H-119Sn correlations, is
particularly suited for the determination of weak cou-
pling constants between protons and low abundant spin
1/2 nuclei when the coupling satellites are unresolved
in the standard or HMQC spectra (see Experimental
Section).24,25
The value found for this coupling constant is strongly
dependent on the solvent: 1.05 ( 0.04 Hz in CD2Cl2 and
4.01 ( 0.05 Hz in DMSO-d6. This observation is again
in line with the fact that the µ2-OH groups are involved
in H-bridge interactions with the counteranion in CD2-
Cl2 solution. This should be associated with weakening
of the O-H bond and, accordingly, result in a small
2J (1H-O-119Snh) scalar coupling between this OH and
the six-coordinate 119Sn nucleus, as observed. In con-
trast, in DMSO-d6, where such an interaction is no
2
longer present, the J (1H-O-119Snh) scalar coupling is
considerably larger and is apparently representative of
2J (1H-O-119Snh) couplings of µ2-OH hydroxy bridges
bound to tin without H-bond interactions toward charged
species such as the PTS- anion.19 However, this does
not exclude weaker H-bonds with DMSO.
Stu d y of th e Rea ction betw een Bu Sn O(OH) a n d
HP TS. Reaction conditions were varied, and attention
was paid to the starting sulfur-to-tin ratio (S/Sn ) 2/12,
2.5/12, 3/12, 3.5/12, 4/12, 8/12), the solvent which
controls the reflux temperature (cyclohexane, toluene,
or xylene), and the reflux time (from 1 to 48 h). The
main results are given in Table 4. Except for the starting
ratio S/Sn ) 8/12 (for which some additional unidenti-
fied broad and weak resonances were observed (-295,
-481, and -487 ppm)), the 119Sn NMR fingerprint of
{(BuSn)12O14(OH)6}(PTS)2 (1; -282.8 and -461.8 ppm)
constituted apparently the only identifiable set of
signals for the crude products. However, the integration
curves (Figure 5) reveal the presence of a hidden signal
in the noise at the low-frequency side of the six-
coordinate 119Sn resonance. This arises probably from
ill-defined butyltin oxo polymeric species that are
soluble in the same organic solvents as compound 1 (i.e.,
benzene, toluene, cyclohexane, xylene, dichloromethane,
chloroform, THF, DMSO, 1,4-dioxane, DMF). Their very
broad signals in solution 119Sn NMR likely result from
too long rotational correlation times related to their
polymeric nature.
(23) The solution structural model was constructed as follows. The
macrocation was built with
a D3d symmetry using the averaged
distances and angles of the X-ray structure (Table 1). The hydrogen
atoms of the µ2-OH groups were placed with the following conditions:
d(O-H) ) 1.00 Å and the O-H bond parallel to the 3-fold axis. The
sulfonate group of PTS- was also built using the averages of the X-ray
structure (Table 1), while its benzene ring was set to an ideal geometry;
i.e., d(C-C) ) 1.39 Å, d(C-H) ) 1.09 Å, (C-C-C) ) 120°, and
(C-C-H) ) 120°. PTS- was aligned on the 3-fold axis of the cluster,
its oxygen atoms facing the µ2-OH groups. The location of PTS- relative
to the macrocation was fixed according to the distance between the
ortho protons of the PTS- and the protons of the µ2-OH group,
determined to be 3.8 Å by NMR experiments. To take into account the
free rotation of the benzene ring along the S-C bond (aligned on the
3-fold axis), this distance was considered as the distance between two
planes, both perpendicular to the 3-fold axis, the first one passing
through the ortho protons and the second one through the protons of
the µ2-OH. This model fully defines a possible geometry for the cation-
anion interaction and allows the distance d(Ocation-Oanion) to be
calculated at 2.5 Å.
Solid-state MAS NMR with a Hahn echo provided
more direct evidence. Figure 6 compares experimental
and simulated 119Sn NMR MAS spectra obtained with
(24) Willker, W.; Leibfritz, D. Magn. Reson. Chem. 1995, 33, 632.
(25) Martins, J . C.; Biesemans, M.; Willem, R. Prog. NMR Spectrosc.,
in press.

1946 Organometallics, Vol. 19, No. 10, 2000
Eychenne-Baron et al.
Ta ble 4. Exp er im en ta l Con d ition s a n d Selected Da ta for th e Rea ction of Bu Sn O(OH) w ith
p-Tolu en esu lfon ic Acid
exptl conditions
chem anal. of crude prod.c
% compd 1 in crude prod.
mass of crude
product,b mg
HPTS/12 Sn
solva
time, h
Sn, %
S/12 Sn
crystd
RMNe
2.0
2.5
3.0
3.5
4.0
8.0
4.0
4.0
4.0
4.0
4.0
T
T
T
T
T
T
T
T
T
C
X
48
48
48
48
48
48
1
18.4
20.3
21.8
20.8
22.6
21.9
25.2
23.3
23.7
20.6
23.9
51.8
51.7
48.1
49.4
47.9
39.9
46.5
46.7
46.8
ndg
1.46
1.51
2.50.
2.26
3.10
6.66
3.02
3.43
3.57
nd
11
40
50
60
55
50
∼5
50
50
50
65
65
xxxf
60
55
50
0
xxx
xxx
xxx
xxx
xxx
6
24
48
48
nd
nd
a
b
Legend: T, toluene (bp 111 °C); C, cyclohexane (bp 81 °C); X, xylene (bp 140 °C). Soluble product obtained after reaction and recovered
by filtration and evaporation under reduced pressure (see Experimental Section). c For {(BuSn)12O14(OH)6}(PTS)2: Sn, 51.3% and S/12
Sn ) 2. From the yield obtained by crystallization in dioxane and subsequent drying (see Experimental Section), (2%. e From quantitative
d
119Sn NMR (see Experimental Section), (5%. f “xxx” indicates that the crystallization step did not proceed correctly. Visually, millimetric
crystals (1‚diox) were mixed with a fine powder. Global elemental analyses for such precipitates were incompatible with the only presence
g
of compound 1 (S/Sn * 2/12). nd ) not determined.
F igu r e 5. Experimental integration curves in the solution
(CD2Cl2) 119Sn{1H} NMR spectra of {(BuSn)12O14(OH)6}-
(4-CH3C6H4SO3)2 (1; left panel) and of a crude reaction
product (right panel) corresponding to S/Sn ) 3/12, 48 h,
toluene. Integrals are only comparable within each of the
spectra.
a Hahn echo for compound 1 and a crude product (S/Sn
) 3/12, 48 h, toluene). For compound 1, the results are,
as expected, identical within experimental error to those
presented in Table 2 for a standard 119Sn MAS experi-
ment. For the crude product, the solid-state 119Sn NMR
fingerprint of compound 1 is again observed (sites 1-3
F igu r e 6. Experimental and simulated 119Sn MAS NMR
spectra obtained with a rotor-synchronized Hahn echo for
of Figure 6 corresponding, respectively, to sites X-Z of
Table 2), but one additional, extremely broad, anisotropy
pattern (site 4 in Figure 6) can now also be deconvoluted
and accounts for roughly 35% of tin nuclei. This amount
matches satisfactorily the one missing in quantitative
solution 119Sn NMR. The 10-fold broader lines of site 4
were never visible in a standard MAS experiment,
where they are lost in the dead time because of their
rapid decay.26 Site 4 is attributed to the ill-defined
additional species.
(a) {(BuSn)12O14(OH)6}(4-CH3C6H4SO3)2 (1) and for a crude
reaction product (b) corresponding to S/Sn ) 3/12, 48 h,
toluene. νMAS ) 13.5 kHz, τ ) 74 µs, and isotropic
resonances are denoted with arrows.
Quantitative solution 119Sn NMR (Table 4) enabled
us to optimize the reaction conditions. Substituting
toluene (bp 110.6 °C) for cyclohexane (bp 80.7 °C) or
xylene (bp 140 °C) gave a larger proportion of compound
1 in the crude materials (65% against 50% in toluene),
but crystallization could not eliminate byproducts.
Increasing the refluxing time from 1 to 48 h did not
change the percentage of 1 in the crude product (ca.
50%) but was needed for correct crystallization. The best
(26) (a) Massiot, D.; Farnan, I.; Gautier, N.; Trumeau, D.; Trokiner,
A.; Coutures, J .-P. Solid State NMR 1995, 4, 241. (b) Fayon, F.;
Bessada, C.; Massiot, D.; Farnan, I.; Coutures, J .-P. J . Non-Cryst.
Solids 1998, 232-234, 403.

Tin-Based Organic-Inorganic Materials
Organometallics, Vol. 19, No. 10, 2000 1947
Ta ble 5. Cr ysta llogr a p h ic Da ta a n d Refin em en t
yield in pure crystallized compound 1‚diox (60%) was
obtained from a starting S/Sn ratio of 3/12, with toluene
refluxing for 48 h.
Deta ils for 1‚d iox
formula
Mr
Sn12C66H136O28S2
2866.7
cryst color, habit
cryst size
cryst syst
colorless, ∼parallelepiped
0.5 × 0.3 × 0.3 mm3
triclinic
Exp er im en ta l Section
space group
unit cell dimensions
a
b
c
R
â
P1h (No. 2)
Syn th eses. Butyltin hydroxide oxide, BuSnO(OH) (Aldrich
or Strem Chemicals), and p-toluenesulfonic acid monohydrate,
HPTS‚H2O (Fluka), were used as received. The reactions were
performed in a 1 L round-bottom flask equipped with a Dean-
Stark apparatus water trap and a condenser. For each experi-
ment, 20 g of BuSnO(OH) and the appropriate amount of
HPTS‚H2O for various starting S/Sn ratios (2/12, 2.5/12, 3/12,
3.5/12, 4/12, or 8/12) were suspended in 500 mL of solvent
(cyclohexane, toluene, or xylene) and refluxed for 1-48 h,
during which time water was trapped in the Dean-Stark
apparatus. Subsequently, the reaction mixture was cooled and
filtered on a fritted glass (No. 4). The clear solutions obtained
were evaporated under reduced pressure to yield a white
amorphous crude solid. In contrast to the starting materials,
BuSnO(OH) and HPTS‚H2O, all crude products are quite
soluble in dichloromethane (up to 300 mg in 0.5 mL) and could
be characterized by 119Sn NMR. Crystallizations were per-
formed in dioxane containing 0.5% of water.27 A 2 mL portion
of dioxane was used for each 1 g of crude product. The dioxane
solutions were cleared by heating at 85 °C and then returned
slowly to room temperature and left still for a few days. A clean
crystallization was not obtained for all experiments (i.e., the
crystals were mixed with a fine powder). Crystals were isolated
by filtration (fritted glass No. 2) and washed with about 50
mL of dioxane. Finally, crystals were dried overnight at 80 °C
to yield compound 1. Yields for various conditions are reported
in Table 4.
12.722(3) Å
14.070(2) Å
16.014(3) Å
114.00(1)°
96.62(2)°
104.24(1)°
2462(24) Å3
γ
V
Z
Dc
1
1.93 g cm-3
F(000)
diffractometer
radiation (λ)
1388
Enraf-Nonius CAD-4
Mo KR (0.71069 Å);
graphite monochromator
31.0 cm-1
room temp
ω-2θ
(0.8 + 0.345 tan θ)°
1-25°
-15 to +15; -16 to +15; 0-19
8984
8645 (Rint ) 0.0192)
DIFABS (min: 0.89; max: 1.15)
5927 [I > 3.00σ(I)]/0/490
full-matrix least squares on F
µ
T
scan type
scan width
θ range for data collecn
hkl ranges
no. of rflns collected
no. of unique rflns
abs correction
no. of data/restraints/params
refinement method
secondary extinctn param ×106 34.0
final indices:a R; Rw (w ) 1)
goodness of fit on F
residual electron density,
min/max
0.0326; 0.0340
2.16
-0.56/+0.70 e Å-3
1‚d iox. Anal. Found: Sn, 49.4; C, 27.3; H, 4.6; S, 2.2. Calcd
for Sn12C62H128O26S2‚C4H8O2: Sn, 49.69; C, 27.65; H, 4.79; S,
R ) ∑||Fo| - |Fc||/∑|Fo|; Rw ) [∑(w|Fo - Fc| )/∑(wFo2)]1/2
.
a
2
1
2.24. See Table 3 for 119Sn, H, and 13C NMR data.
1. Anal. Found: Sn, 51.0; C, 26.8; H, 4.7; S, 2.4. Calcd for
Sn12C62H128O26S2: Sn, 51.27; C, 26.80; H, 4.65; S, 2.30. See
Table 3 for 119Sn NMR data.
CH2 and CH3. Full-matrix least-squares refinement, based on
F, of atomic parameters and anisotropic thermal parameters
for non-H atoms and of isotropic thermal parameters only
for H atoms were carried out with CRYSTALS programs.30
For H atoms, only two isotropic thermal parameters were
considered: one for H atoms of µ2-OH groups and one for all
other H atoms. The atomic scattering factors were provided
by CRYSTALS.30 Final refinement details are given in Table
5. The numbering scheme employed is shown in Figure 1. The
oxygen atoms inside the clusters are numbered with respect
to the tin atoms they are bound with: e.g., O126 is bound to
Sn1, Sn2, and Sn6 (or their symmetric counterparts) and O46
is bound to Sn4 and Sn6. The oxygen atoms of the sulfonate
are numbered with respect to the µ2-OH they are hydrogen-
bound to: e.g., O45X is hydrogen-bound to O45.
Th er m a l An a lysis. Thermogravimetric and differential
thermal analyses were carried out simultaneously, on
Netzsch STA 409 apparatus, using 50-100 mg of product in
an alumina crucible, a pure oxygen atmosphere, and a 10 °C/
min heating ramp from 20 to 1100 °C.
Con d u ctivity Exp er im en ts. Measurements were per-
formed in a thermostated (25 ( 0.05 °C) vessel with a Tacusel
CD 810 conductimeter equipped with a Philips cell. The cell
constant was determined prior to each series of measurements
with a potassium chloride solution (10-2 mol/L) of known ionic
conductivity. The measurements were performed for concen-
trations from 5 × 10-3 to 5 × 10-2 mol/L in CD2Cl2 or DMSO.
Solid -Sta te 119Sn MAS NMR Exp er im en ts. The 119Sn
MAS (magic angle spinning) NMR experiments have been
Cr ysta llogr a p h y. Samples suitable for single-crystal X-ray
diffraction were obtained by recrystallizing compound 1 in
dioxane with less than 0.1% of water. Intensity data for the
colorless crystal of 1‚diox were collected at room temperature
on a Enraf-Nonius CAD4 diffractometer fitted with a graphite
monochromator (Mo KR radiation; λ ) 0.71069 Å). The crystal
was sealed in a Lindemann glass capillary tube. Details
concerning the crystallographic data collection and structure
determination are given in Table 5. Cell dimensions were
determined from 25 reflections (13.9 < θ < 14.3°) dispersed
in reciprocal space. Two standard reflections were monitored
every 2 h during data collection and showed less than 10%
decay, which was nevertheless corrected, assuming a linear
variation. Intensities were corrected for Lorentz and polariza-
tion effects, and an empirical absorption correction was
applied.28 The structure was solved using direct methods with
the SHELXS program.29 Successive Fourier maps were used
to locate all non-H atoms and some H atoms (those of the PTS-,
those on the carbon atoms of butyl chains with small displace-
ment parameters, mainly CR and Câ, and two of the three
bridging hydroxy groups (O45 and O56)). The other H atom
positions were computed from the expected geometry of sp3
a
(27) The use of anhydrous dioxane (less 0.1% of water) resulted in
an incomplete crystallization, as evidenced by lower yields. The use of
dioxane with 1% of water resulted in a faster, but unclean, crystal-
lization. Therefore, dioxane with 0.5% of water was preferred for
crystallizing 1‚diox.
(28) Walker, N.; Stuart, D. Acta Crystallogr., Sect. A 1983, 39, 158.
(29) Sheldrick, G. M. SHELXS-86, Program for Automatic Solution
of Crystal Structure; University of Go¨ttingen, Go¨ttingen, Germany,
1986.
(30) Watkin, D. J .; Prout, C. K.; Carruthers, J . R.; Betteridge, P.
W. CRYSTALS issue 10; Chemical Crystallography Laboratory, Uni-
versity of Oxford, Oxford, U.K., 1996.

1948 Organometallics, Vol. 19, No. 10, 2000
Eychenne-Baron et al.
performed on a Bruker MSL300 spectrometer (111.92 MHz
for 119Sn) equipped with a 4 mm high-speed locked Bruker
probe. The spectral width was 200 000 Hz (∼1800 ppm); pulse
angles and recycling delays were about 30° (1.5 µs) and 10 s,
respectively. Longer recycling delays (up to 30 s) gave identical
quantification within experimental error. Moreover, for com-
pound 1 the longitudinal relaxation time (T1) was measured
by saturation recovery around 10 and 17 s for five- and six-
coordinate tin atoms, respectively. Typically 1000-5000 tran-
sients were necessary to achieve reasonable signal-to-noise
ratios. 119Sn chemical shifts are quoted relative to Me4Sn, using
solid tetracyclohexyltin (δiso -97.35 ppm) as a secondary
external reference.32 At least two experiments, with sufficiently
different spinning rates, were run in order to identify the
isotropic chemical shifts. The spinning frequencies were
stabilized to (5 Hz.
The solid-state NMR experiments with a Hahn echo have
been carried out using a Bruker DSX 300 spectrometer
operating at 7.04 T with a Larmor frequency of 111.92 MHz
for 119Sn. The MAS spectra were acquired using a rotor-
synchronized Hahn echo sequence (θ-τ-2θ-τ-acq; with θ ≈
30° and τ ) 1/νMAS, ca. 74 µs for 13 500 Hz). The pulse
durations were limited to 2 µs in order to ensure complete
excitation of the spectra. The recycling delay was set to 70 s
for compound 1 and to 60 s for the crude product. The spinning
frequency was stabilized to (10 Hz. Chemical shifts were
referenced to tetramethyltin, using a solution of 1 in CH2Cl2
as a secondary external reference.
of compound 1. The integral of each resonance (-283 and -462
ppm) gives the same results within 5%, which can be consid-
ered as the accuracy of the method.
The proton-detected 2D 1H-119Sn HMQC experiment was
recorded at 303 K on a Bruker AMX500 spectrometer, inter-
faced with a Silicon Graphics O2 computer, operating at 500.13
and 186.50 MHz for 1H and 119Sn, respectively, without 119Sn
decoupling, using the pulse sequences of the Bruker library36
adapted to include gradient pulses,37 as proposed and il-
lustrated recently.19,38
The phase-sensitive ROESY and NOESY spectra18,19
were recorded from pulse sequences of the standard Bruker
library, at variable mixing times with 4K × 512 data matrices
(F1 zero-filled to 1K). Distances separating protons were
calculated from the intensity of the corresponding cross-peaks,
using the distance between two protons in mutually ortho
positions as an internal reference (2.48 Å)22 and the equation
17,20,21
ri ) rref(kref/ki)1/6
.
In this equation ri represents the
interatomic distance of interest and rref the reference distance,
while kref and ki are the slopes of the respective build-up
straight lines in the ROESY spectra,17,20,21 in the initial rate
approximation, associated with the cross-peaks mutually
correlating the pairs of nuclei under consideration. The above
formula only holds if the reference pair and the pair of protons
of interest are subject to comparable rotational tumbling
regimes.20,21 The 2D ROESY experiments were performed with
mixing times of 400, 600, and 800 ms in CD2Cl2 and with
mixing times of 300, 600, and 900 ms in DMSO-d6 (both at
303 K). The 2D NOESY experiments in DMSO-d6 were
performed with mixing times of 400, 600, and 800 ms at 303
K. The volumes of the cross-peaks were used in the calculation
instead of the slopes of the build-up straight lines to which
they are in principle proportional, to avoid time-consuming
build-up experiments.
The principal components of the 119Sn shielding tensors were
analyzed with WINFIT software33 using the Herzfeld and
Berger approach.34 They are reported, following Haeberlen’s
notation,35 as the isotropic chemical shift (δiso ) -σiso), the
anisotropy (ú ) σ33 - σiso), and the asymmetry (η ) |σ22 - σ11|/
|σ33 - σiso|), σ11, σ22, and σ33 being the three components of the
shielding tensor expressed in its principal axis system with
the following convention: |σ33 - σiso| g |σ11 - σiso| g |σ22 - σiso|.15
With this convention, ú is a signed value expressed in ppm
and η is a dimensionless parameter, the value of which is
between 0 and 1. The accuracy on δiso, ú, and η corresponds to
the digital resolution ((0.5 ppm), (10 and (0.05 ppm,
respectively.
The 1H-119Sn J -HMQC spectra were recorded with the
pulse sequence of Willker and Leibfritz,24 adapted with the
gradient pulse schemes previously proposed for 1H-119Sn
HMQC spectroscopy.19,38b The 119Sn frequency carrier was set
on resonance at the frequency of the six-coordinate tin atom.
A total of 32 delays were used for total preparation periods of
620 ms in CD2Cl2 and of 310 ms in DMSO-d6. The J -HMQC
technique is essentially an HMQC experiment in which a 180°
pulse is applied between two identical but increasingly incre-
mented time delays, embedded in a preparation period which
is kept constant.24 This introduces a sine modulation in the
1
Solu tion NMR Exp er im en ts. Routine 119Sn, H, and 13C
NMR experiments were performed on a Bruker AC300 spec-
trometer (300.13, 111.92, and 75.47 MHz for 1H, 119Sn, and
13C, respectively). Proton-decoupled 119Sn NMR spectra were
obtained with a composite pulse decoupling sequence (WALTZ),
and 119Sn chemical shifts are relative to external tetramethyl-
tin. 1H and 13C chemical shifts were referenced to the residual
solvent peak (CD2Cl2) and converted to the standard SiMe4
scale by adding 5.32 and 53.3 ppm for 1H and 13C nuclei,
respectively.
Quantitative 119Sn NMR experiments were performed as
follows. The 119Sn NMR spectra of samples made of a precisely
weighed amount of crude product (ca. 100 mg) in 0.5 mL of
CD2Cl2 were recorded (1500 transients) without proton decou-
pling to avoid NOE effects. The recycling delay was 3 s, far
above the longitudinal relaxation time (T1) of both 119Sn
environments, which were measured around 0.15 and 0.20 s
for five- and six-coordinate tin nuclei, respectively. Their
integrations, in absolute mode, were compared to a reference
obtained the same day, under the very same experimental
conditions, from a tube containing 100 mg of compound 1 and
0.5 mL of CD2Cl2. The linearity of the measurement was
assessed with sample tubes containing various known amounts
1
amplitude of the finally detected H-119Sn HMQC correlation,
which is determined by the incremented delay and the coupling
constant to be measured. This sine-modulated signal ampli-
tude is not affected by relaxation damping. The desired
coupling constant is then simply extracted from curve fitting
of the experimentally generated sine function. Methodological
and theoretical details as to the implementation of this
technique to the 119Sn nucleus, with gradient pulses, will be
published elsewhere.25 The confidence intervals given with the
2J (1H-O-119Snh) coupling constant values represent the stan-
dard deviation on the mean values found from two independent
experiments for each solvent (CD2Cl2 and DMSO-d6).
(36) Bax, A.; Griffey, R. H.; Hawkins, B. L. J . Magn. Reson. 1983,
55, 301.
(37) (a) Keeler, J .; Clowes, R. T.; Davis, A. L.; Laue, E. D. Methods
Enzymol. 1994, 239, 145. (b) Tyburn, J .-M.; Bereton, I. M.; Doddrell,
D. M. J . Magn. Reson. 1992, 97, 305. (c) Ruiz-Cabello, J .; Vuister, G.
W.; Moonen, C. T. W.; Van Gelderen, P.; Cohen, J . S.; Van Zijl, P. C.
M. J . Magn. Reson. 1992, 100, 282. (d) Vuister, G. W.; Boelens, R.;
Kaptein, R.; Hurd, R. E.; J ohn, B. K.; Van Zijl, P. C. M. J . Am. Chem.
Soc. 1991, 113, 9688.
(31) Watkin, D. J .; Prout, C. K.; Pearce, L. J .; CAMERON; Chemical
Crystallography Laboratory, University of Oxford, Oxford, U.K., 1996.
(32) Reuter, H.; Sebald, A. Z. Naturforsch. 1992, 48B, 195.
(33) Massiot, D.; Thiele, H.; Germanus, A. Bruker Rep. 1994, 140,
43.
(34) Herzfeld, J .; Berger, A. E. J . Chem. Phys. 1980, 73, 6021.
(35) Haeberlen, U. Adv. Magn. Reson. 1976, Suppl. 1.
(38) (a) Kayser, F.; Biesemans, M.; Gielen, M.; Willem, R. J . Magn.
Reson. 1993, A102, 249. (b) Martins, J . C.; Kayser, F.; Verheyden, P.;
Gielen, M.; Willem, R.; Biesemans, M. J . Magn. Reson. 1997, 124, 128.
(c) Kayser, F.; Biesemans, M.; Gielen, M.; Willem, R. In Advanced
Applications of NMR to Organometallic Chemistry; Gielen, M., Willem,
R., Wrackmeyer, B., Eds.; Wiley: Chichester, U.K., 1996; Chapter 3,
pp 45-86.

Tin-Based Organic-Inorganic Materials
Organometallics, Vol. 19, No. 10, 2000 1949
Ack n ow led gm en t. We acknowledge Drs. J . Vais-
sermann and F. Robert for their help with the X-ray
structure, J . Maquet for her precious assistance in solid-
state 119Sn MAS NMR, G. Dureau and C. Parussolo for
their experimental work, and Eng. I. Verbruggen for
technical assistance in NMR acquisitions. F.R., C.S.,
M.B., and R.W. are indebted to the European Union
Program “Human Capital and Mobility” for financial
support (Contract No. ERBCHRX-CT-94-0610). M.B.
and R.W. are indebted to the Fund for Scientific
Research Flanders (Belgium, Grant No. G0192.98) for
financial support. F.R., C.S., M.B., and R.W. are in-
debted to the Flemish Ministry of Education and the
French Ministries of Foreign Affairs and Education,
Research and Technology for the allocation of a Tourne-
sol Grant (No. 99 091). J .C.M. is a postdoctoral fellow
of the fund for Scientific Research Flanders (Belgium,
FWO).
Su p p or tin g In for m a tion Ava ila ble: Further details of
the structure determination, including bond distances and
angles and thermal parameters for {(BuSn)12O14(OH)6}(4-
CH3C6H4SO3)2‚C4H8O2 (1‚diox). This material is available free
of charge via the Internet at http://pubs.acs.org.
OM990877A