Synthesis and characterization of triphenyl-, tri-n-butyl and di-n-butyltin derivatives of 4-carboxybenzo-18-crown-6 and -15-crown-5

Article abstract of DOI:10.1016/S0022-328X(99)00035-2

¹H-, ¹³C- and ¹¹⁷Sn-NMR as well as ^119mSn Moessbauer spectroscopy, electrospray mass spectrometry and elemental analysis of novel trioganotin and di-n-butyltin derivatives of 4-carboxybenzo-18-crown-6 and -15-crown-5 are reported. The X-ray crystal structure of aquatriphenyltin-4,7,10,13,16-pentaoxadicyclo[13.4.0]nonadeca-1,3(17),18- trienecarboxylate hydrate consists of trigonal bipyramidal tin with a C₃ trigonal plane and the axial positions occupied by an oxygen atom, derived from a monodentate carboxylate ligand, and a water molecule. In the lattice, the crown ether portions of the molecules are capped on either side, via hydrogen bonding interactions, by the coordinated and uncoordinated water molecules.

Full text of DOI:10.1016/S0022-328X(99)00035-2

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 582 (1999) 195–203
Synthesis and characterization of triphenyl-, tri-n-butyl and
di-n-butyltin derivatives of 4-carboxybenzo-18-crown-6 and
-15-crown-5
Martine Kemmer a, Laurent Ghys a, Marcel Gielen a,b,*, Monique Biesemans b,c,
Edward R.T. Tiekink d, Rudolph Willem b,c
a Uni6ersite´ Libre de Bruxelles, Ser6ice de Chimie Organique, a6e. F. D. Roose6elt, 50, B-1050 Brussels, Belgium
b AOSC Unit, Faculty of Applied Sciences, Free Uni6ersity of Brussels VUB, Pleinlaan 2, B-1050 Brussels, Belgium
c High Resolution NMR Centre, Free Uni6ersity of Brussels VUB, Pleinlaan 2, B-1050 Brussels, Belgium
d Department of Chemistry, The Uni6ersity of Adelaide, Adelaide, Australia 5005
Received 22 December 1998
Abstract
1H-, 13C- and 117Sn-NMR as well as 119mSn Mo¨ssbauer spectroscopy, electrospray mass spectrometry and elemental analysis of
novel trioganotin and di-n-butyltin derivatives of 4-carboxybenzo-18-crown-6 and -15-crown-5 are reported. The X-ray crystal
structure of aquatriphenyltin-4,7,10,13,16-pentaoxadicyclo[13.4.0]nonadeca-1,3(17),18-trienecarboxylate hydrate consists of trigo-
nal bipyramidal tin with a C3 trigonal plane and the axial positions occupied by an oxygen atom, derived from a monodentate
carboxylate ligand, and a water molecule. In the lattice, the crown ether portions of the molecules are capped on either side, via
hydrogen bonding interactions, by the coordinated and uncoordinated water molecules. © 1999 Elsevier Science S.A. All rights
reserved.
Keywords: Triphenyltin derivative; Tri-n-butylin derivative; Di-n-butylin derivative; 4-Carboxybenzo-18-crown-6; 4-Carboxybenzo-15-crown-5
shown that organotin carboxylates show a great struc-
tural diversity in the solid state [18,19] and hence, the
crystal structure of one derivative, i.e. aquatriphenyltin
4-carboxybenzo-15-crown-5 (5), has also been deter-
mined. It was found to incorporate a water molecule in
the coordination sphere, a feature which remains rela-
tively unusual in organotin chemistry [20–23]. In vitro
antitumour activities [24–26] of these new compounds
against seven human tumour cell lines were reported
previously in a comparative screening with organotin
polyoxaalcanecarboxylates [27].
1. Introduction
After Pedersen’s discovery in 1967 of the first crown
ethers and their properties to bind alkali metal cations
[1,2], cation–macrocycle interactions have been studied
intensively [3,4]. Although adducts between organotin
(IV), inorganic tin (IV) and inorganic tin (II) and crown
ethers are the subject of current interest [5–12], organ-
otin compounds with crown ether moieties bound di-
rectly via covalent bonds to tin remain rare [13].
The synthesis of new triphenyltin, tri-n-butyltin and
di-n-butyltin carboxylates with carboxylate ligands con-
taining an 18-crown-6 or a 15-crown-5 moiety are
reported herein. All compounds were characterized by
2. Results and discussion
elemental analysis, H-, 13C- and 117Sn-NMR as well as
1
119mSn Mo¨ssbauer spectroscopy and electrospray mass
spectrometry [14–17]. Crystallographic studies have
2.1. Synthesis
The compounds synthesised are depicted in Fig. 1.
Triphenyl and tri-n-butyltin carboxylates were ob-
tained by the reaction of triphenyltin hydroxide or
* Corresponding author. Tel.: +32-629-3279; fax: +32-6299-3281.
E-mail address: mgielen@vub.ac.be (M. Gielen)
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00035-2

196
M. Kemmer et al. / Journal of Organometallic Chemistry 582 (1999) 195–203
Fig. 1. Structures proposed for compounds 1 to 8.
tri-n-butyltin acetate with 4-carboxybenzo-18-crown-6
or 4-carboxybenzo-15-crown-5, respectively (Eqs. (1)
and (2)).
contain an additional potential donor atom, the major-
ity of the structures adopt one of two basic motifs as
shown in Fig. 2. In the extreme, motif B is monomeric
and contains four-coordinate tin and motif C is poly-
meric with five-coordinate tin. Five-coordinate, trigonal
bipyramidal tin is also found in a small number of
structures where an additional neutral ligand, normally
water, is incorporated in the coordination geometry, i.e.
in R3Sn(O2CR%)L, shown as motif A in Fig. 2. The
structures that are known to adopt this motif are
(C6H5)3SnOH+RCOOH“(C6H5)3SnOCOR+H2O
(1)
Bu3SnOCOCH3+RCOOH“Bu3SnOCOR
+CH3COOH
(2)
The starting material for di-n-butyltin carboxylates was
di-n-butyltin oxide [28], which yields two different com-
pounds depending on the molar ratio acid/tin engaged
in the reaction: bis[di-n-butyl(carboxylato)tin]oxide for
a 1/1 ratio and di-n-butyltin di(carboxylate) for a 2/1
ratio (Eqs. (3) and (4)).
4Bu2SnO+4RCOOH“{[Bu2Sn(OCOR)]2O}2+2H2O
(3)
Bu2SnO+2RCOOH“Bu2Sn(OCOR)2+2H2O
2.2. X-ray structure of 5
(4)
Triorganotin carboxylates, R3SnO2CR%, are known
to adopt a variety of motifs in the solid state [18,19,29].
For derivatives in which the organic residue does not
Fig. 2. Possible structures for triorganotin carboxylates [18,19].

M. Kemmer et al. / Journal of Organometallic Chemistry 582 (1999) 195–203
197
Fig. 3. Molecular structure and crystallographic numbering scheme employed for 5.
[Me3Sn(O2C5H4N-2)OH2] [30], [n-Bu3Sn(N-phthaloyl-
glycinate)OH2] [31], {Ph3Sn[O2CC6H4(NꢀN(C6H3-4-
OH-5-CHO))-o]OH2} [32] and [Ph3Sn(O2CCl3)MeOH]
[33]. The structure of 5 also adopts this motif as shown
in Fig. 3; selected interatomic parameters are collected
in Table 1.
can be formulated that motif A is realized simply
from motif B by trans-substitution of the carbonyl
oxygen for a water ligand, accompanied by a change of
configuration of tin from cis to trans.
2.3. NMR spectroscopy
,
The tin atom lies 0.2569(6) A out of the trigonal
1
All compounds were characterized by H-, 13C- and
plane defined by the three ipso carbon atoms of the
1
117Sn-NMR in CDCl3. The H-NMR data are reported
phenyl rings, in the direction of the O(1) atom. The
1
,
Sn–O(1) bond distance of 2.120(6) A is significantly
in Table 2. For compounds 1 and 5, the H chemical
,
shorter than the Sn–O(2) separation of 2.937(6) A.
shift ranges of the triphenyltin moiety were deduced
from signal intensities and from estimated 3J(1H–
117/119Sn) coupling constants. The assignment of the
butyltin moiety for compounds 2 to 4, 6 and 7 is based
,
Further, there are no intermolecular contacts B4.0 A
formed between the tin and O(2) atoms leading to the
conclusion that the carboxylate ligand coordinates in
the monodentate mode. As expected the Sn–O(8) dis-
n
on J(1H–1H) coupling constants, multiplicities, signal
integration, 1H–13C HMQC and 1H–13C HMBC exper-
iments. Signal overlapping precluded the determination
of the 2J(1H–119/117Sn) and 3J(1H–119/117Sn) coupling
constants for compounds 2–4 and 6–8. The proton
chemical shifts of H(3), H(5) and H(6) were assigned on
the basis of nJ(1H–1H) coupling constants and were
further confirmed by 1H–13C HMQC and 1H–13C
,
tance of 2.471(6) A, i.e. involving the water molecule, is
significantly longer than the Sn–O(1) distance. In addi-
tion to the presence of coordinated water, there is
solvent water in the lattice which participates in hydro-
gen bonding.
The coordinated water molecule forms three close
contacts in the lattice. These are O(8)–H(81)…O(3)i
i
i
1
,
,
2.35 A [O(8)…O(3) 3.099(8) A, O(8)–H(81)…O(3)
HMBC experiments. The methylenic H chemical shifts
i
,
,
135°], O(8)–H(81)…O(7) 2.12 A [2.919(8) A, 141°] and
of the crown ether moieties were assigned at least in part
i
,
,
O(8)–H(82)…O(5) 2.32 A [2.777(8) A, 109°]; symmetry
operation i: 0.5+x, 0.5−y, −0.5+z. Similarly, the
solvent water molecule forms three close contacts:
Table 1
,
,
O(9)–H(91)…O(4) 2.76 A [3.022(9) A, 109°], O(9)–
,
Selected bond lengths (A) and angles (°) for 5
,
,
H(91)…O(5) 2.92 A [3.277(9) A, 121°] and O(9)–
,
,
H(92)…O(6) 1.65 A [2.896(8) A, 173°]. This arrange-
ment implies that all ether oxygen atoms participate
in intermolecular hydrogen bonding. In the lattice the
crown ether moieties are aligned parallel to the a-axis.
They do not form channels as the distance between
successive crown ethers corresponds to the a-distance
Sn–O(1)
2.120(6)
2.120(8)
2.145(7)
1.234(9)
Sn–O(8)
Sn–C(22)
C(1)–O(1)
2.471(6)
2.134(7)
1.905(10)
Sn–C(16)
Sn–C(28)
C(1)–O(2)
O(1)–Sn–O(8)
O(1)–Sn–C(22)
O(8)–Sn–C(16)
O(8)–Sn–C(28)
C(16)–Sn–C(28)
Sn–O(1)–C(1)
177.4(2)
97.0(2)
82.7(2)
87.3(2)
111.2(3)
112.6(5)
O(1)–Sn–C(16)
O(1)–Sn–C(28)
O(8)–Sn–C(22)
C(16)–Sn–C(22)
C(22)–Sn–C(28)
99.7(3)
92.9(3)
80.4(2)
135.4(3)
108.9(3)
,
of 10.217(5) A. Indeed, each crown ether is ‘capped’
on one side by the coordinated water molecule and on
the other by the solvent water molecule as per the
hydrogen bonding scheme described above. Formally it

198
M. Kemmer et al. / Journal of Organometallic Chemistry 582 (1999) 195–203
Table 2
1H-NMR data in CDCl3 of compounds 1 to 8 a
1
2
–
–
3
–
–
4
–
–
5
6
–
–
7
–
–
8 b
–
CH(o)
7.7–7.8
m [60]
7.4–7.5
m
7.7–7.8
m [60]
7.4–7.5
m
CH(m)(p)
CH(3)
–
7.62
d (2)
7.7–7.8
m
6.91
d (9)
4.1–4.3
m
3.8–4.0
m
3.6–3.8
m
7.54
d (2)
7.63
dd (8, 2)
6.82
d (8)
4.1–4.3
m
3.8–4.0
m
3.6–3.8
m
7.58
s
7.49
s
7.60
7.54
d (2)
7.63
dd (8, 2)
6.82
d (8)
–
7.59
d (2)
7.74
dd (8, 2)
6.86
d (8)
–
7.54
s
d (2)
7.7–7.8
m
6.82
d (8)
–
CH(5)
7.73
d (8)
6.86
d (8)
4.1–4.3
m
3.8–4.0
m
3.6–3.8
m
7.54
d (8)
6.84
d (8)
4.1–4.3
m
3.8–4.0
m
3.6–3.8
m
7.60
m, u
6.89
d (8)
–
CH(6)
CH2(8)(17)
CH2(9)(16)
CH2(10)(11)(14)(15)
CH2(12)(13)
CH2(8)(15)
CH2(9)(14)
CH2(10)(11)(12)(13)
HOH
–
–
–
–
–
–
–
–
–
–
–
–
3.67
Cs
–
3.65
Cs
–
3.65
Cs
–
3.62
Cs
–
4.1–4.2
m
3.8–3.9
m
3.73
Cs
ꢀ2.0
b
4.1–4.2
m
3.8–3.9
m
3.73
Cs
ꢀ2.0
b
1.2–1.4
m
1.6–1.7
m
1.2–1.4
m
0.89
t (7)
4.1–4.2
m
3.8–4.0
m
3.75
Cs
–
4.1–4.3
m
3.9–4.0
m
3.77
Cs
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
ꢀ2.0
bs
1.2–1.3
m
1.6–1.7
m
1.2–1.3
m
CH2(a)
1.7–1.8
m
1.7–1.8
m
1.37
tq (7, 7)
0.86
1.4–1.6
m
1.6–1.8
m
1.1–1.4
m
0.7–0.9
m
–
1.7–1.8
m
1.7–1.8
m
1.38
tq (7, 7)
0.86
1.5–1.7
m
1.6–1.8
m
1.2–1.5
m
0.7–0.9
m
CH2(b)
–
–
–
CH2(g)
CH3(d)
0.89
t (7)
t (7)
t (7)
a Chemical shifts in ppm with respect to TMS; coupling constants in Hz, nJ(1H–1H) in parentheses, nJ(1H–117/119Sn) between square brackets.
Abbreviations: s=singlet; Cs=pseudo singlet; d=doublet, dd=doublet of doublets; m=complex pattern; b=broad; t=triplet; tq=triplet of
quartets.
b Product 8 contains 7; u=undefined because of signal overlapping of 7 and 8.
1
1
from signal integration and from H–13C HMQC and
solved in the H spectra.
1H–13C HMBC spectra in areas where overlapping is
limited.
The 117Sn-NMR data are given in Table 4. All com-
pounds except 4 and 8 exhibit a single resonance. The
two resonances of equal intensities for 4 and 8 result
from their dimeric structure characterized by endo- and
exo-cyclic tin atoms (see Fig. 1) [28]. The 117Sn chemi-
cal shifts of compounds 1, 2, 4 and 5 are characteristic
for four-coordination in solution [36,37]. Those of com-
pounds 3 and 7 confirm the proposed structure.
The 13C-NMR data are shown in Table 3. J(13C–
n
117/119Sn) satellites and signal intensities were used to
assign the 13C chemical shifts of the triphenyltin, tri-
n-butyltin and di-n-butyltin moieties [34,35]. No
1J(13C–117/119Sn) were observed for the C(ipso) sig-
nals, due to low intensities. Compounds 4 and 8
showed broader 13C resonances therefore precluding
the observation of any J(13C–117/119C) coupling con-
2.4. Mo¨ssbauer spectroscopy
n
stants. The aromatic 13C signals of the carboxylate
moiety were assigned on the basis of H–13C HMQC
The Mo¨ssbauer parameters are listed in Table 5. The
quadrupole splittings QS are found in the range of
3.28–3.41 mm s−1, except for triphenyltin carboxylates
having values of 2.33 for compound 1 and 2.77 for
compound 5. The latter are values excluding polymeric
pentacoordinate structures of type C (see Fig. 2) [36–
1
and H–13C HMBC, and 13C DEPT-135 experiments,
1
the former spectra being needed for the crown ether
moiety. The assignment could not be achieved further
than the g-position of the crown ether, with respect to
the aromatic ring, owing to their signals being unre-

M. Kemmer et al. / Journal of Organometallic Chemistry 582 (1999) 195–203
199
Table 3
13C-NMR data in CDCl3 of compounds 1 to 8 a
1
2
3
4
5
6
7
8 b
C(i)
C(o)
C(m)
C(p)
C(7)
C(1)
C(2)
CH(3)
138.5
137.0 [47/49]
129.0 [61/63]
130.2 [13]
172.7
152.9
148.0
114.9
122.8
125.1
111.7
70.80
70.77
70.71
70.66
70.53
70.51
69.4
–
–
–
–
–
–
–
–
–
–
–
–
138.7
–
–
–
–
–
–
–
–
–
–
–
–
136.9 [47/49]
128.9 [61/65]
130.1 [13]
172.8
153.1
148.3
115.7
123.3
125.2
112.1
171.4
152.2
148.1
115.0
125.0
124.2
112.1
70.96
70.84
70.77
70.73
70.66
70.61
69.5
69.4
68.9
68.8
–
175.7
153.3
148.3
115.3
122.7
124.9
112.3
70.9
70.9
70.81
70.76
70.73
70.67
69.5
69.4
69.2
69.0
–
172.6
152.5
148.3
115.3
126.3
124.0
112.4
70.8
70.8
70.7
70.6
70.6
70.5
69.42
69.35
69.1
68.9
–
171.4
152.5
148.4
115.5
125.1
124.4
112.3
–
175.8
153.5
148.5
115.4
122.9
125.0
112.2
–
172.6
152.6
148.4
115.4
126.3
124.1
112.3
–
C(4)
CH(5)
CH(6)
CH2(10)(11)(12)(13)(14)(15)
–
CH2(9)(16)
–
–
–
–
–
–
–
–
69.2
68.8
68.6
–
CH2(8)(17)
CH2(10)(11)(12)(13)
70.95
70.92
70.31
70.23
69.3
69.2
68.9
68.5
–
71.2
71.2
71.11
71.09
70.39
70.31
69.4
69.2
69.0
68.6
25.5
71.11
71.09
70.42
70.34
69.4
69.3
69.0
68.7
29.7
[n.o.]
28.6
[n.o.]
27.7
27.4
26.7
26.6
13.68
13.61
70.57
70.52
69.59
69.49
69.1
68.9
16.6
[350/362]
CH2(9)(14)
CH2(8)(15)
CH2(a)
–
–
–
–
–
–
–
–
–
16.6
[341/358]
25.4
[569/596]
29.5
[n.o.] c
28.3
[n.o.]
26.7
26.6
27.6
27.4
13.5
13.4
[561/588]
CH2(b)
CH2(g)
CH3(d)
–
–
–
27.9
[20]
27.0
[62/65]
13.7
26.7
[33]
26.3
[95]
13.5
–
–
–
27.9
[20]
27.0
[62/65]
13.6
26.7
[34]
26.4
[103]
13.6
a Chemical shifts in ppm with respect to TMS; nJ(13C–117/119Sn) coupling constants between square brackets.
b Sample contains 7.
c n.o.=not observed.
Table 4
117Sn-NMR data in CDCl3 of compounds 1 to 8 a
1
2
3
4
5
6
7
8
−115.7
108.2
−156.2
−213.0
−217.3
−116.3
107.4
−156.8
−212.5
−216.9
a Chemical shifts in ppm with respect to (CH3)4Sn.
38]. The difference of 0.44 mm s−1 between the QS
values of the triphenyltin compounds 1 and 5 is higher
than for tributyltin carboxylates (0.12 mm s−1) or
dibutyltin dicarboxylates (0.11 mm s−1). This is consis-
tent with 1 and 5 having necessarily a slightly different
tin-atom geometry in solid state, since 5 is found hy-
drated while 1 is not, the X-ray analysis for 5 revealing
an unusual type-A structure as shown in Fig. 2. A
type-B structure can be proposed for compound 1
although it cannot be inferred whether there is a co-

200
M. Kemmer et al. / Journal of Organometallic Chemistry 582 (1999) 195–203
Table 5
2.5. Electrospray mass spectrometry
119mSn Mo¨ssbauer parameters: QS (mm s−1) quadrupole splitting, IS
(mm s−1) isomer shift relative to Ca119SnO3, Y1 and Y2 (mm s−1) line
width
Table 6 shows the monoisotopic mass spectra (1H,
12C, 14N, 16O, 23Na, 39K, 120Sn) in the cationic mode of
water/acetonitrile solutions. Complexation by direct or
hydrolyzed fragments or solvent molecules are observed
frequently. The hydrolyzed species give an indication
about the stability inside the spectrometer [39]. Adducts
with alkali cations (Na+ and K+) are observed for all
compounds. Complexation with alkali metal ions gener-
ates a cation which often facilitates the detection by the
spectrometer [14–16]. The cations originate from the
starting free acids, 4-carboxybenzo-18-crown-6 and -15-
crown-5. This is not unusual since the crown ether
moiety is complexed easily by alkali cations (Na+ and
K+) and NH4+ [40]. In some cases, complexation with
alkali cations gave the only evidence for the existence of
the molecular mass of the basic compound M.
QS
IS
Y1
Y2
1
2
3
4
5
6
7
8
2.33
3.41
3.40
3.36
2.77
3.29
3.28
3.38
1.24
1.44
1.39
1.27
1.23
1.45
1.41
1.33
0.76
0.94
0.72
0.96
0.99
0.94
0.92
0.98
0.81
0.94
0.85
0.99
0.94
0.88
0.93
0.95
Table 6
Characteristic electrospray fragment-ions for compounds 1–7 a
Fragment
1
5
M+Na+
M+K+
729
745
685
701
2.6. Elemental analyses
2
647
665
6
C and H elemental analyses have been performed for
all compounds (see Table 7). Compounds 2, 5 and 6 are
found to contain water: compounds 2 and 5 (bulk
powder) contain one water molecule per triorganotin
carboxylate and compound 6 contains water in a (2/1)
triorganotin carboxylate/water ratio. The presence of
M+H+
M+H2O+H+
M+NH+4
M+Na+
620
625
669
3
967
7
879
895
M+Na+
M+K+
1
water was confirmed by H-NMR and, for compound
5, also by single crystal X-ray diffraction analysis.
4
1217
1233
8
M/2+Na+
M/2+K+
1129
1145
3. Experimental
a Only fragments from M are listed.
3.1. Synthesis
Table 7
Elemental analysis of compounds 1 to 7 (found [calculated])
3.1.1. Triorganotin carboxylates
Structure
C
H
Compounds 1 and 5 are prepared typically by mixing
equimolar amounts of triphenyltin hydroxide (515 mg;
1.40 mmol) and the appropriate 4-carboxybenzocrown
(356 mg or 438 mg; 1.40 mmol) in 250 ml benzene in a
500 ml flask equipped with a Dean–Stark funnel. The
mixture is refluxed for 4–48 h. The binary azeotrope
benzene/water is distilled off up to 50% of the initial
solvent volume. The remaining solution is evaporated
under vacuum. The synthesis with tri-n-butyltin acetate
yielding 2 and 6 is analog under elimination of acetic
acid.
1
2
3
4
5
6
7
C35H38SnO8
C29H50SnO8 · H2O
60.2 [59.60]
52.5 [52.50]
53.5 [53.46]
50.0 [50.35]
58.4 [58.34]
53.1 [53.14]
53.9 [53.35]
5.5 [5.43]
8.3 [7.90]
7.1 [6.84]
7.1 [6.94]
5.7 [5.35]
7.8 [7.77]
6.7 [6.60]
C
42H64SnO16
C100H164Sn4O34
33H34SnO7 · H2O
C
C27H46SnO7 · 1/2H2O
C38H56SnO14
ordination from the carbonyl oxygen to tin [36–38].
The QS values for 2 and 6 are typical for a polymeric
structure of type-C with an equatorial SnR3 unit and
two apical carboxylates [36–38], corresponding to a
five-coordinate structure in the solid state. The two
different tin atoms of compound 4 could not be dis-
criminated by Mo¨ssbauer spectroscopy since the
method is less sensitive to small variations to the tin
environment than 117Sn NMR spectroscopy [28]. The
QS values of compounds 3, 4 and 7 are in agreement
with the structure proposed in Fig. 1 [27].
3.1.2. Diorganotin carboxylates
Di-n-butyltin oxide is refluxed in benzene with the
appropriate amount of 4-carboxybenzocrown (1/1 mo-
lar ratio 4-carboxybenzocrown+di-n-butyltin oxide for
3 and 7; 2/1 molar ratio for 4 and 8) under the same
conditions as for the triorganotin carboxylates.
Compound 8 could not be separated from 7 by
chromatography on Sephadex LH-20 or recrystalliza-

M. Kemmer et al. / Journal of Organometallic Chemistry 582 (1999) 195–203
201
Table 8
Synthesis data for compounds 1 to 8
M.p. (°C)
Yield (%)
Reflux time
Purification method
1
2
3
4
110–112
45–47
125–127
96–98
98
80
96
90
10
4
6
Recrystallization from diethyl ether/hexane
Recrystallization from hexane/chloroform
Recrystallization from hexane/chloroform
Sephadex LH–20; elution with methylene chloride/chloroform; recrystallization from hexane/
chloroform
12
5
6
7
8
130–131
Liquid
95
90
98
48
25
48
20
Recrystallization from hexane
Sephadex LH-20; elution with methylene chloride/chloroform
Recrystallization from petroleum ether/methylene chloride
Sephadex LH-20; elution with methylene chloride/chloroform a
130–132
90–105 a
a Unseparable from 7.
tion. This is probably due to a disproportionation
reaction which yields 7 and di-n-butyltin oxide as sup-
ported by the formation of a precipitate in the NMR
tube during data acquisition.
Table 8 summarises all experimental synthesis details.
Compound 5 appears as a solid sample which is essen-
tially a powder with monohydrate composition (ele-
mental analysis). In this bulk, only a few crystals,
suitable for X-ray diffraction, can be observed and
selected. These crystals appear to exist as a dihydrate
rather than the monohydrate of the bulk.
coupled with a Masslynx system (ionisation in an elec-
tric field of 3.5 kV; source temperature: 80°C; source
pressure: 1 atm; analyzer pressure: 10−5 mbar) [51,52].
Cone voltages were 15 V for compound 2, 30 V for
compounds 3, 7 and 8, 50 V for compound 6, 80 V for
compound 4 and 90 V for compounds 1 and 5.
3.5. X-ray crystallography
Intensity data for a colourless crystal of 5 were
collected at 200 K on a Rigaku AFC6R diffractometer
,
employing Mo–Ka radiation (u=0.71073 A) and the
3.2. NMR measurements
ꢀ:2q scan technique to 2qmax of 50.0°. The data set was
corrected for Lorentz and polarisation effects [53] as
well as for absorption employing an empirical proce-
dure [54]. Data that satisfied the I]3.0s(I) criterion of
observability were used in the subsequent analysis.
Crystal data and refinement details are given in Table 9.
All 2D-NMR spectra were recorded on a Bruker
AMX500 spectrometer interfaced with a X32 computer
1
and operating at 500.13 and 125.77 MHz for H and
13C nuclei, respectively. All 1D-NMR spectra were
acquired on a Bruker AC250 instrument equipped with
a Quattro probe tuned to 250.13, 62.93 and 89.15 MHz
1
1
for H, 13C and 117Sn nuclei, respectively. H and 13C
Table 9
Crystallographic data for 5
chemical shifts were referenced to the standard Me4Si
scale from respectively residual H and 13C–2H solvent
1
Formula
C33H38O9Sn
697.4
Monoclinic
P21/n
10.217(5)
17.388(9)
17.837(10)
101.08(4)
3109(2)
4
resonances of chloroform (CHCl3, 7.23 and CDCl3,
77.0 ppm for 1H and 13C nuclei, respectively). The 117Sn
resonance frequencies were set from the absolute refer-
ence ](117Sn)+35.632295 MHz [41,42]. 2D gradient
Formula weight
Crystal system
Space group
,
a (A)
,
b (A)
1
enhanced H–13C HMQC [43] and HMBC [44] correla-
,
c (A)
tion spectra were acquired using the pulse sequences of
the Bruker program library, adapted to include gradi-
ent pulses [45–48], as described recently [49].
i (°)
3
,
V (A )
Z
Crystal size (mm3)
0.10×0.24×0.32
1.489
Dc (g cm−3
F(000)
)
3.3. Mo¨ssbauer spectroscopy
1432
8.75
v (cm−1
)
The Mo¨ssbauer spectra were recorded as described in
Ref. [50].
No. of data collected
No. of unique data
No. of reflections with I]3.0|(I)
5733
5413
3565
R
Rw
0.050
0.064
3.4. Mass spectrometry
G.O.F.
Residual zmax/zmin (e A
2.47
0.86/−1.23
−3
The electrospray mass spectra were recorded in the
cationic mode on a Micromass Quattro II instrument
,
)

202
M. Kemmer et al. / Journal of Organometallic Chemistry 582 (1999) 195–203
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on F [53]. Non-hydrogen atoms were refined with an-
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(1995) 87.
,
(C–H 0.97 A); O–H atoms were located from a differ-
ence map. The refinements were continued until conver-
gence employing Sigma weights, i.e. 1/s2(F). Selected
interatomic parameters are collected in Table 1 and the
crystallographic numbering scheme employed is shown
in Fig. 1 which was drawn with ORTEP [56] at 50%
probability ellipsoids.
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Crystallographic data for the structural analysis has
been deposited with the Cambridge Crystallographic
Data Centre; CCDC No. 112253 for compound 5.
Copies of the information may be obtained free of
charge from The Director, CCDC, 12 Union Road,
Cambridge, CB2 1EZ, UK (Fax: +44-1223-336033;
e-mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
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Acknowledgements
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The Australian Research Council is gratefully ac-
knowledged for the support of the crystallographic
facility (E.R.T.T.). We thank I. Verbruggen for record-
ing NMR spectra, Professor G. Laus and M. Desmet
for the mass spectra and Professor B. Mahieu for the
Mo¨ssbauer spectra. This research was supported by the
‘Ministe`re de l’Education Nationale du Luxembourg’
(grants no. BFR93/051, BPU96/130 and BPU97/138,
M.K.), the ‘Action Lions Vaincre le Cancer du Luxem-
bourg’ (M.K.), the Belgian ‘Nationaal Fonds voor
Wetenschappelijk Onderzoek’ (N.F.W.O. grant no.
G.0054.96, M.G.), and the Fund for Scientific Research
Flanders (Belgium, grant no. G.0192.98, R.W.).
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