Organotin(IV) derivatives of some O,C,O-chelating ligands

Article abstract of DOI:10.1021/om020361i

The series of organotin(IV) complexes L^1-3SnPh_nCl_3-n, where L^1-3 are O,C,O-chelating ligands (called the pincer ligands), 2,6-bis(alkoxymethyl)phenyl-, 2,6-(ROCH₂)₂C₆H₃^- (L¹, R = Me, L², R = i-Pr, L³, R = t-Bu, n = 3-0), have been synthesized and characterized by ¹H, ¹³C, and ¹¹⁹Sn NMR spectroscopy, MS-ESI spectrometry, and elemental analysis. The structure of selected compounds L¹SnPh₃ (1), L¹SnPh₂Cl (2), L¹SnPhCl₂ (3), L¹SnCl₃ (4), L²SnPhCl₂ (7), and L³SnPhCl₂ (11) was studied by X-ray crystallography and ¹¹⁹Sn CP/ MAS NMR spectroscopy in the solid state. The determination of crystal structures reveals the similarity of all the shapes of coordination polyhedra. The deformations of the shapes of coordination polyhedra depend on the degree of donor-acceptor Sn-O interaction (from very weak (interatomic distance Sn-O 2.963(1) ?) to medium-strong (2.475(1) ?)), which increases with increasing Lewis acidity of the tin atom in the L^1-3SnPh_nCl_3-n entities and decreases with increasing steric demands of substituants R (from Me to t-Bu). NMR spectroscopy indicates a similar structural arrangement of the studied compounds in solution.

Full text of DOI:10.1021/om020361i

3996
Organometallics 2002, 21, 3996-4004
Or ga n otin (IV) Der iva tives of Som e O,C,O-Ch ela tin g
Liga n d s
Roman J ambor,*,† Libor Dosta´l,† Alesˇ Ru˚zˇicˇka,† Ivana C´ısarˇova´,‡ J irˇ´ı Brus,§
Michal Holcˇapek, and J aroslav Holecˇek†
Department of General and Inorganic Chemistry and Department of Analytical Chemistry,
Faculty of Chemical Technology, University of Pardubice, na´m. Cˇ s. legiı´ 565, CZ-532 10,
Pardubice, Czech Republic, Faculty of Science, Charles University in Prague, Hlavova 2030,
128 40 Praha 2, Czech Republic, and Institute of Macromolecular Chemistry of the Academy of
Sciences of the Czech Republic, Heyrovsky sq. 2, 162 06 Praha 6, Czech Republic
Received May 6, 2002
The series of organotin(IV) complexes L1-3SnPhnCl3-n, where L1-3 are O,C,O-chelating
ligands (called the pincer ligands), 2,6-bis(alkoxymethyl)phenyl-, 2,6-(ROCH2)2C6H3- (L1, R
1
) Me, L2, R ) i-Pr, L3, R ) t-Bu, n ) 3-0), have been synthesized and characterized by H,
13C, and 119Sn NMR spectroscopy, MS-ESI spectrometry, and elemental analysis. The
structure of selected compounds L1SnPh3 (1), L1SnPh2Cl (2), L1SnPhCl2 (3), L1SnCl3 (4),
L2SnPhCl2 (7), and L3SnPhCl2 (11) was studied by X-ray crystallography and 119Sn CP/
MAS NMR spectroscopy in the solid state. The determination of crystal structures reveals
the similarity of all the shapes of coordination polyhedra. The deformations of the shapes of
coordination polyhedra depend on the degree of donor-acceptor Sn-O interaction (from very
weak (interatomic distance Sn-O 2.963(1) Å) to medium-strong (2.475(1) Å)), which increases
with increasing Lewis acidity of the tin atom in the L1-3SnPhnCl3-n entities and decreases
with increasing steric demands of substituents R (from Me to t-Bu). NMR spectroscopy
indicates a similar structural arrangement of the studied compounds in solution.
Ch a r t 1
In tr od u ction
Investigation of the organotin compounds is interest-
ing because of their biological activity,1 reactivity,2 and
industrial applications.3 Unexpected structural aspects
and reactivities are usually associated with the presence
of so-called hypervalent or hypercoordinated organotin
compounds.4 The representatives of such organotin
compounds containing intramolecularly coordinating
* Corresponding author. Fax: ++420 46 603 7068. E-mail:
roman.jambor@upce.cz.
† Department of General and Inorganic Chemistry, University of
Pardubice.
‡ Charles University in Prague.
Y,C,Y-chelating ligands (Y ) heteroatom-containing
substituent) seem to be very popular at the present
time. In particular, nitrogen-containing ligands of this
Y,C,Y-type A (Chart 1) are studied extensively.
Recently, this nitrogen-containing type of ligand has
been shown to be very useful in organotin cation
stabilization.5 On the other hand, only a few examples
of oxygen donor atom-containing ligands of this Y,C,Y-
type are known. Recently, J urkschat et al. reported the
synthesis of a series of organotin compounds containing
an O,C,O-coordinating pincer ligand of type B (Chart
1), in which the possibility of hypercoordination of the
tin atom through Sn-O interaction has been demon-
strated.6 On the basis of this information, we have
decided to focus on synthesis of new O,C,O-chelating
ligands of type C (Chart 1).
§ Institute of Macromolecular Chemistry of the Academy of Sciences
of the Czech Republic.
Department of Analytical Chemistry, University of Pardubice.
(1) (a) Nath, M.; Yadav, R.; Eng G.; Musingarimi, P. Appl. Orga-
nomet. Chem. 1999, 13, 29, and references therein. (b) Crowe, A. J . In
Metal Complexes in Cancer Chemotherapy; Keppler, B. K., Ed.; VCH:
Weinheim, Germany, 1993; pp 369-379. (c) Gielen, M.; Lelievield, P.;
de Vos, D.; Willem, R. Metal-Based Drugs. In Metal-Based Antitumor
Drugs; Gielen, M., Ed.; Freund Publishing House: Tel Aviv, Israel,
1992; Vol. 2, pp 29-54.
(2) (a) Pieper, N.; Klaus-Mrestani, C.; Schu¨rmann, M.; J urkschat,
K.; Biesemans, M.; Verbruggen, I.; Martins, J . C.; Willem, R. Orga-
nometallics 1997, 16, 1043. (b) Kolb, U.; Dra¨ger, M.; Dargatz, M.;
J urkschat, K. Organommetallics 1995, 14, 2827. (c) Dakternieks, D.;
Dyson, G.; J urkschat, K.; Tozer, R.; Tiekink, E. R. T. J . Organomet.
Chem. 1993, 458, 29.
(3) Pinnavaia, T. J . Science 1983, 220, 4595.
(4) (a) Akiba, K., Ed. Chemistry of Hypervalent Compounds;
Wiley-VCH: Weinheim, Germany, 1999, and references therein. (b)
J astrzebski, J . T. B. H.; Boersma, J .; Esch, P. M.; van Koten, G.
Organometallics 1991, 10, 930. (c) Mitzel, N. W.; Losehand, U.;
Richardson A. Organometallics 1999, 18, 2610. (d) Buntine, M. A.;
Kosovel, F. J .; Tiekink, R. T. Phosphorus, Sulfur Silicon Relat. Elem.
1999, 150-151, 261, and references therein. (e) J urkschat, K.; Pieper,
N.; Seemeyer, S.; Schu¨rmann, M.; Biesemans, M.; Verbruggen, I.;
Willem, R. Organometallics 2001, 20, 868.
(5) (a) J ambor, R.; C´ısarˇova´, I.; Ru˚zˇicˇka, A.; Holecˇek, J . Acta
Crystallogr. 2001, C57, 373. (b) van Koten, G.; Noltes, J . G. J . Am.
Chem. Soc. 1976, 98, 5393.
10.1021/om020361i CCC: $22.00 © 2002 American Chemical Society
Publication on Web 08/23/2002

Organotin(IV) Derivatives of O,C,O-Chelating Ligands
Organometallics, Vol. 21, No. 19, 2002 3997
Sch em e 1
F igu r e 1. General view (ORTEP) of a molecule showing
30% probability displacement ellipsoids and the atom-
numbering scheme for 1. The hydrogen atoms are omitted
for clarity.
This paper describes the synthesis of monoanionic
O,C,O-chelating ligands [C6H3(CH2OR)2-2,6]- (R ) Me
(L1), i-Pr (L2), and t-Bu (L3)) and their organotin
derivatives (1-11) (Scheme 1).
presence of excess of AgO (eq 2). This way of preparation
led to higher yield of this compound.
Detailed solution NMR studies of these compounds
and also solid state NMR studies and X-ray crystal
structure determinations of selected compounds 1-4,
7, and 11 are described. These compounds enable study
of the effect of moderation of the Lewis acidity of the
tin center on the number and magnitude of the intra-
molecular tin-oxygen interactions (1-4). Furthermore,
this series also enables us to observe the dependence of
the Sn-O interaction strength on increasing ligand
spatial hindrance (3, 7, 11).
Compounds 1-4 were prepared as white crystalline
solids by reaction of L1Br with n-BuLi followed by
addition to a precooled hexane solution of the appropri-
ate organotin halide. If both the solutions (Li salt and
organotin halide) are prepared in Et2O/hexane at -78
°C, the best yield is obtained (no attack of the solvent
was observed at this temperature),7 while at 0 °C L1Li
metalates Et2O, and consequently no formation of
compounds 1-4 was observed at this temperature.
Treatment of L2Br (L3Br) with n-BuLi in hexane at
ambient temperature results in a yellow solution, from
which the L2Li (L3Li) salt is obtained as a white solid,
following crystalization from the saturated hexane
solution at -78 °C. The subsequent reaction of the L2Li
(L3Li) salt with the appropriate organotin halide led to
formation of compounds 5-8 (9-11) (see Scheme 1).
Molecu la r Str u ctu r es of 1-4, 7, a n d 11. The
molecular structures of these compounds are depicted
in Figures 1-6, respectively. The crystallographical data
and selected bond lengths and angles are given in
Tables 1-2.
Resu lts a n d Discu ssion
Syn t h et ic Asp ect s. The 1-bromo-2,6-bis(alkoxy-
methyl)benzenes (L1-3Br) were used as starting com-
pounds to prepare all of compounds 1-11. The reaction
of 1-bromo-2,6-bis(bromomethyl)benzene with excess
sodium methanolate or potassium tert-butoxyde affords
1-bromo-2,6-bis(methoxymethyl)benzene (L1Br) and
1-bromo-2,6-bis(tert-butoxymethyl)benzene (L3Br) with
good yields (eq 1), while the isopropoxy-substituted
ligand (L2Br) was prepared by the reaction of 1-bromo-
2,6-bis(bromomethyl)benzene with 2-propanol in the
The shapes of the coordination polyhedra are mutu-
ally similar for all the studied compounds. They differ
from tetrahedral arrangement only in the extent of
(6) (a) Mehring, M.; Vrasidas, I.; Horn, D.; Schu¨rmann, M.; J urk-
schat, K. Organometallics 2001, 20, 4647. (b) Mehring, M.; Lo¨w, Ch.;
Uhlig, F.; Schu¨rmann, M.; J urkschat, K.; Mahieu, B. Organometallics
2000, 19, 4613. (c) Vicente, J .; Arcas, A.; Blasco, M. A.; Lozano, J .; de
Arellano, M. C. R. Organometallics 1998, 17, 5374.
(7) For similar results see: Dakternieks, D.; J urkschat, K.; Tozer,
R.; Hook, J .; Tiekink, E. R. T. Organometallics 1997, 16, 3696.

3998 Organometallics, Vol. 21, No. 19, 2002
J ambor et al.
F igu r e 2. General view (ORTEP) of a molecule showing
50% probability displacement ellipsoids and the atom-
numbering scheme for 2. Only one molecule from the
crystal lattice of 2 without hydrogen atoms has been chosen
for clarity.
F igu r e 4. General view (ORTEP) of a molecule showing
50% probability displacement ellipsoids and the atom-
numbering scheme for 4. Only one molecule from the
crystal lattice of 4 without hydrogen atoms has been chosen
for clarity.
F igu r e 5. General view (ORTEP) of a molecule showing
50% probability displacement ellipsoids and the atom-
numbering scheme for 7. The hydrogen atoms are omitted
for clarity.
F igu r e 3. General view (ORTEP) of a molecule showing
50% probability displacement ellipsoids and the atom-
numbering scheme for 3.
covalent radii (2.066 Å),9 thus representing a weak or
medium-strong Sn-O interaction. As a consequence of
this interaction, some carbon and chlorine atoms depart
declinations, resulting in a natural transformation of
the tetrahedron to an octahedron on passage from 1 to
4.8 The values of Sn-O bond lengths (from 2.475(1) to
2.966(1) Å) are substantially smaller than the sum of
the van der Waals radii of oxygen and tin (3.70 Å)9 in
the studied compounds, but larger than the sum of the
(8) The other interpretation of selected crystal structures can be
that compounds 1 and 11 are examples of [4+2] coordination where a
C4Sn- (for 1) and C2Cl2Sn- (for 11) tetrahedron is cis-attacked by
two oxygen donor atoms, while compounds 2 and 7 are examples of
[5+1] coordination where distorted C3ClOSn-trigonal bipyramids are
attacked by an oxygen donor atom.
(9) Bondi, A. J . Phys. Chem. 1964, 68, 441.

Organotin(IV) Derivatives of O,C,O-Chelating Ligands
Organometallics, Vol. 21, No. 19, 2002 3999
Ta ble 1. Cr ysta llogr a p h ic Da ta for 1-4, 7, a n d 11
1
2
3
4
7
11
formula
MW
C
28H28O2Sn
C22H23ClO2Sn
473.54
C16H18Cl2O2Sn
431.89
C10H13Cl3O2Sn
390.24
C20H26Cl2O2Sn
488.0
C23H31Cl5O2Sn
635.42
515.19
cryst syst
space group
a [Å]
b [Å]
c [Å]
monoclinic
P21/ n [No. 14]
13.9090(2)
12.3270(10)
14.6260(2)
orthorhombic
Pccn [No. 56]
24.9610(1)
25.6590(2)
12.8190(2)
trigonal
triclinic
monoclinic
P21/ n [No. 14]
13.4890(3)
8.6040(2)
orthorhombic
Pca21 [No. 29]
17.8700(2)
13.4180(2)
11.3790(2)
P32 [No. 145]
12.5240(2)
12.5240(2)
9.2900(2)
P1h [No. 2]
9.5510(3)
12.1790(3)
12.6470(4)
106.9140(18)
99.2940(16)
94.0710(19)
4
17.7460(3)
R [deg]
â [deg]
γ [deg]
Z
106.5671(7)
97.8520(13)
120.00
3
1261.92(4)
1.705
4
16
4
4
V [Å3]
2403.61(5)
1.424
8210.24(15)
1.532
1378.12(7)
1.881
2040.28(7)
1.589
2728.45(7)
1.547
Dx [g cm-3
]
cryst size [mm]
cryst shape
0.3 × 0.27 × 0.12 0.48 × 0.12 × 0.1 0.5 × 0.5 × 0.35 0.25 × 0.25 × 0.12 0.25 × 0.15 × 0.075 0.3 × 0.2 × 0.15
plate
bar
prism
1.837
29.13
plate
2.418
27.54
plate
bar
µ [mm-1
]
1.084
1.388
1.525
1.444
θ
max [deg]
range of h;k;l
27.50
27.50
27.50
27.50
-18,18; 15,16;
-19,18
-32,32; -33,33;
-17,17; -17,17; -10,12; -15,15;
-12,12 -16,15
16 486 23 056
-17,17; -11,11;
-21,23;-17,17;
-16,16
-22,23
-14,14
no. of measd reflns 43 076
no. of ind diffract. 5504 (0.040)
124 846
9420 (0.054)
32 616
4684 (0.044)
45 202
6257 (0.043)
4497 (0.031)
6251 (0.045)
a
(Rint
)
no. of obsd diffract. 5005
7696
4452
5903
4115
5772
[I > 2σ(I)]
T
min, Tmax
0.804, 0.899
282
0.0261, 1.3408
0.801, 0.874
473
0.0373, 6.9015
0.508,0.583
192
0.076,0.2685
-0.012(10)
0.561, 0.740
293
0.0242, 1.6462
0.798,0.895
230
0.0293,1.1498
0.696, 0.810
286
0.0400, 1.4556
-0.015(17)
no. of params
b
w1, w2
abs struct param
(Flack)
R,c wR for obsd
diffract.
0.022, 0.054
0.029, 0.070
0.015,0.034
0.026, 0.067
0.026, 0.059
0.028,0.069
R; wR for all data 0.026,0.056
0.041, 0.076
1.055
0.015,0.034
1.112
0.028, 0.068
1.093
0.033, 0.062
1.046
0.032, 0.071
1.049
GOFd
1.052
residual electron
0.382, -0.783
0.658, -0.761
0.306, -0.504
0.953, -0.924
0.743, -0.839
0.715, -0.542
density [e/Å3]
a
2
2
2 b
Rint ) ∑|Fo - Fo,mean |/∑Fo
.
Weighting scheme: w ) [σ2(Fo2) + (w1P)2 + w2P]-1, where P ) [max(Fo2) + 2Fc2]. c R(F) ) ∑||Fo| -
|Fc||/∑|Fo|, wR(F2) ) [∑(w(Fo - Fc2)2)/(∑w(Fo2)2)]1/2
.
GOF ) [∑(w(Fo - Fc2)2)/(Ndiffrs - Nparams)]1/2
.
2
d
2
F igu r e 7. Alternative descriptions of coordination geom-
etry (tetrahedron A, octahedron B) of the studied com-
pounds.
another description of the coordination geometry of the
studied compounds. The other atoms bonded to the tin
atom occupy the axial positions (Figure 7). The oxygen
donor groups are bound to the tin atom in cis fashion,
resulting in a pseudofacial O,C,O-coordination mode
of the ”pincer” ligands in this description. This cis
arrangement of oxygen atoms is retained even in
diorganotin compounds 3, 7, and 11, in contrast to the
related diorganotin dichloride derivatives containing
another O,C,O-coordinating pincer ligand, C6H2[P(O)-
(OEt)2]2-1,3-t-Bu-5, where the oxygens are bound to the
tin atom in trans fashion.10
F igu r e 6. General view (ORTEP) of a molecule showing
50% probability displacement ellipsoids and the atom-
numbering scheme for 11. The hydrogen atoms and mol-
ecule of CHCl3 are omitted for clarity.
from true tetrahedral geometry, being situated in the
pseudotrans positions in relation to both oxygen atom
(see the values of angles O(1)-Sn-X and O(2)-Sn-Y
in Table 2).
As the average C-Sn-C angle is 109.22° (109.56° in
the unsubstituted Ph4Sn analogue11), the geometry of
Together with the central tin atoms, these atoms form
the equatorial plane of a deformed octahedron in
(10) Mehring, M.; Schu¨rmann, M.; J urkschat, K. Organometallics
1998, 17, 1227.

4000 Organometallics, Vol. 21, No. 19, 2002
J ambor et al.
Ta ble 2. Selected Bon d Dista n ces (Å) a n d An gles (d eg) F ou n d in Selected Com p ou n d s 1-4, 7, a n d 11
1
2A
2B
3
7
11
4A
4B
X)C31,
Y)C41,
Z)C21
X)Cl1A,
Y)C31A,
Z)C21A
X)Cl1B,
YdC31B,
Z)C21B
X)Cl1,
Y)Cl2,
Z)C21
X)Cl1,
Y)Cl2,
Z)C21
X)Cl1,
Y)Cl2,
Z)C21
X)Cl1A,
Y)Cl2A,
Z)Cl3A
X)Cl1B,
Y)Cl2B,
Z)C13B
Sn1-C11
2.165(2)
2.908(1)
2.966(1)
2.168(2)
2.153(2)
2.144(2)
112.85(6)
109.36(6)
116.98(6)
65.56(5)
66.81(5)
112.01(4)
172.55(5)
74.71(5)
79.67(5)
72.76(5)
168.05(5)
81.78(5)
99.61(6)
107.04(6)
109.58(6)
2.136(2)
2.567(2)
2.993(2)
2.457(1)
2.137(2)
2.125(2)
105.95(7)
114.86(9)
121.91(9)
71.07(8)
64.15(7)
114.42(5)
166.79(4)
78.43(7)
89.18(7)
74.01(4)
164.12(7)
77.41(7)
91.74(6)
102.92(7)
113.38(9)
2.138(2)
2.586(2)
2.891(2)
2.440(1)
2.148(2)
2.130(2)
104.49(7)
113.42(9)
123.93(9)
70.26(7)
64.94(7)
113.12(6)
166.44(4)
77.59(7)
89.25(8)
73.96(5)
166.15(8)
78.09(8)
93.81(6)
103.78(7)
111.80(9)
2.117(1)
2.619(1)
2.655(1)
2.395(1)
2.398(1)
2.121(2)
110.54(5)
105.26(4)
131.30(6)
70.08)5)
68.28(5)
116.95(4)
165.09(3)
76.68(3)
87.13(6)
75.70(3)
159.19(3)
86.75(5)
89.03(2)
102.07(5)
110.58(4)
2.126(2)
2.475(1)
2.985(2)
2.401(1)
2.378(1)
2.142(2)
112.26(6)
106.53(6)
129.13(8)
72.41(7)
64.82(6)
118.43(4)
168.69(4)
79.66(4)
83.56(6)
72.44(3)
152.85(3)
90.76(6)
89.07(2)
100.03(5)
112.40(5)
2.132(3)
2.775(2)
2.882(2)
2.388(1)
2.376(1)
2.112(3)
100.78(8)
111.57(8)
125.4(1)
69.08(9)
68.00(9)
118.83(6)
162.91(5)
75.60(5)
85.78(9)
74.86(5)
162.00(5)
85.72(9)
89.16(3)
106.41(8)
107.11(9)
2.103(2)
2.511(2)
2.557(2)
2.383(1)
2.391(1)
2.340(1)
111.81(7)
110.47(7)
132.62(7)
70.07(8)
68.80(8)
113.75(6)
168.42(5)
79.08(5)
85.54(5)
76.90(5)
164.70(5)
86.40(5)
89.73(2)
100.12(2)
103.49(3)
2.110(2)
2.513(2)
2.583(2)
2.383(1)
2.365(1)
2.337(1)
109.88(7)
117.02(7)
127.95(7)
69.86(8)
69.04(8)
114.89(6)
165.90(5)
78.20(4)
86.25(5)
76.91(5)
166.85(5)
81.69(4)
89.95(2)
103.72(2)
101.24(2)
Sn1-O1
Sn1-O2
Sn1-X
Sn1-Y
Sn1-Z
C11-Sn1-X
C11-Sn1-Y
C11-Sn1-Z
C11-Sn1-O1
C11-Sn1-O2
O1-Sn1-O2
O1-Sn1-X
O1-Sn1-Y
O1-Sn1-Z
O2-Sn1-X
O2-Sn1-Y
O2-Sn1-Z
X-Sn1-Y
X-Sn1-Z
Y-Sn1-Z
Ta ble 3. Selected 13C a n d 119Sn NMR Da ta a for
1 is nearly tetrahedral. The greatest deviations from
ideal tetrahedral shape are found for C(11)-Sn-C(21)
and C(31)-Sn-C(41), 117.11° and 99.33°, respectively
(in Ph4Sn 108.6° and 111.2°).11 The values of both Sn-O
bonds (2.909 and 2.963 Å, respectively) indicate rela-
tively weak intramolecular interactions, but stronger
than those in another triphenyltin(IV) compound con-
taining another O,C,O-pincer ligand, C6H2[P(O)(OEt)2]2-
1,3-t-Bu-5 (3.006 and 3.022 Å, respectively).10 The Sn-
C(21) bond distance is almost identical with the average
bond distance in Ph4Sn, while the other Sn-C bonds
are slightly longer. The elongation of the Sn-C(11) bond
is caused by steric repulsion of the relative rigid ”pincer”
ligand,12 and that of Sn-C(31) and Sn-C(41) is a
consequence of their location in pseudotrans positions
with respect to the oxygen atoms.13
The stepwise shortening of the Sn-O bond distances
from 1 to 4 (increasing Lewis acidity of central tin
atoms) indicates an increasing degree of Sn-O donor-
acceptor interaction. The slight forcing of the Sn-O
coordination leads to a shift in the real shape of the
coordination polyhedron toward octahedral in the tetra-
hedron-octahedron path. The distortion from tetra-
hedral geometry is correlated with the magnitude of
the Sn-O interaction (see Table 2) and is documented
by increasing values of the axial angles defined as
C(11)-Sn-C(21) (compounds 1-3) and C(11)-Sn-Cl(3)
(compound 4), respectively (Figure 7A, B). The Sn-C
and Sn-Cl distances are also slightly shortened step-
wise, due to forcing of the Sn-O donor-acceptor
interaction.
1-11
δ(13C(1)) [ppm]c δ(13C(1′)) [ppm]d
δ(119Sn)iso δ(119Sn) (nJ (119Sn, 13C(1)) (nJ (119Sn, 13C(1′))
compd
[ppm]b
[ppm]
[Hz])
[Hz])
1
2
-163.2
-155.2
-163.3
-196.5
-236e
-163.3
-144.4
137.2 (570.8)
135.3 (729.6)
142.5 (543.1)
142.4 (733.9)
3
4
5
6
7
8
9
-208.8
-270.5
-153.8
-136.1
-177.4
-238.8
-154.0
-121.7
-148.5
134. 8 (997.4)
138.7 (1372.2)
135.5 (542.4)
134.2 (683.8)
132.9 (930.5)
139.6 (1036.2)
133.6 (536.1)
134.2 (714.4)
132.1 (872.4)
141.2 (1027.2)
141.5 (527.1)
143.2 (737.9)
143.4 (996.1)
-191.9
141.4 (520.9)
143.3 (720.6)
144.6 (945.9)
10
11
-161.5
a
Measured in CDCl3. b 119Sn CP/MAS was measured only for
selected compounds 1-4, 7, and 11. c Refers to the tin-bound ipso-
d
carbon of the O,C,O-pincer ligand. Refers to the tin-bound carbon
of the phenyl groups. e Broad signal.
stepwise (see Table 2), as a consequence of steric
repulsion forces of R groups in the CH2OR substituents,
which predominates over the effect of the Sn-O donor-
acceptor interaction.
The existence of one independent molecule in the
crystal lattice of the studied compounds (except 2 and
4, mentioned above) is also reflected by the observation
of only one 119Sn CP/MAS NMR resonance. In addition,
the values of δ(119Sn)iso are close to the values of the
119Sn NMR shifts in solution (see Table 3), indicating
that no intermolecular coordination is present in the
solid state in the studied compounds. The observation
of two resonances in the 119Sn CP/MAS NMR spectrum
for 2 (-155.2 and -163.3 ppm) is in agreement with
the presence of two independent molecules in the crystal
lattice of 2, while the same result has not been found
because of the very broad signal (probably due to the
presence of three quadrupolar atoms 35,37Cl in the
molecule) in the 119Sn CP/MAS NMR spectrum for 4.
The central signal patterns of the 119Sn CP/MAS NMR
spectra of the studied compounds (2, 3, 7, and 11) are
typical for organotin compounds, in which the tin atom
is bonded to one or two chlorides.14
The coordination geometries of 3, 7, and 11 (Figures
3, 5, and 6) seem to be strongly influenced by steric
factors. Despite the slight increase in the Lewis basicity
of the oxygen donor centers in the CH2OR groups in this
set, the Sn-O donor-acceptor interaction is weakened
(11) Belsky, V. K.; Simonenko, A. A.; Reikhsfeld, V. O.; Saratov, I.
E. J . Organomet. Chem. 1983, 244, 125.
(12) Vij, A.; Kirchmeier, R. L.; Willet, R. D.; Shreeve, J . M. Inorg.
Chem. 1994, 33, 5456.
(13) J astrzebski, J . T. B. H.; van Koten, G. Adv. Organomet. Chem.
1993, 35, 241.

Organotin(IV) Derivatives of O,C,O-Chelating Ligands
Organometallics, Vol. 21, No. 19, 2002 4001
Ta ble 4. Tem p er a tu r e Dep en d en ce of Selected 1H
a n d 119Sn NMR P a r a m eter s (r a n ge 170-300 K,
Tolu en e-d 8)
Figure 2 and Table 2). The δ(119Sn) values are shifted
upfield with decreasing temperature (170-360 K, tol-
uene-d8, see Table 4), thus indicating forcing of the
Sn-O interaction at a lower temperature in these
compounds. The dynamic behavior of 2, 6, and 10 with
two ortho-CH2OR substituents with different R groups
was studied at various temperatures of 1H NMR (170-
δ(1H)a [ppm]
δ(119Sn)a
[ppm]
compound
T, K
CH2
4.09
CH3
2.58
1
300
170
300
170
300
170
300
170
300
170
300
170
300
170
300
170
300
170
300
170
300
170
-162.3
-161.1
-142.8
-149.6
-201.3
-215.8
-268.1
-285.2
-153.8
-152.0
-128.3
-152.0
-167.6
-184.3
-189.9
-193.4
-153.2
-154.2
-115.2
-133.2
-138.5
-154.5
3.92
4.25
2.48
2.71
3.07/2.18
2.88
2.81
1
2
360 K, toluene-d8). At room temperature, the H NMR
4.48/3.51
4.29
spectrum displays one set of sharp signals for all the
protons. As the temperature is decreased, first a broad-
ening of the CH2 (for 2, 6, and 10), CH (for 6), and CH3
(for 2, 6, and 10) protons is observed, followed by
decoalescence of all the protons at 200 K for 2, 185 K
for 6, and 170 K for 10, which indicates, as is well-
known, a dissociation/association dynamic procedure16
in these compounds. The energy barriers (∆Gq) of the
fluxional processes (calculated from the Eyring equa-
tion)17 are 35.9 kJ mol-1 for 2, 32.9 kJ mol-1 for 6, and
30.4 kJ mol-1 for 10. The explanation for observations
of different decoalescence temperatures for 2, 6, and 10
can lie in the different strengths of the Sn-O interaction
in these compounds in solution. The strongest Sn-O
interaction seems to be in 2 (where R is Me), while an
increase in the substituent steric bulk attenuates Sn-O
coordination.
3
4.61/3.31b
4.02
4
3.17
c
3.13
5
4.37
4.24
4.55
0.75d
0.74
6
0.69d
0.92/0.12
0.73d
0.72/0.51e
0.94d
1.01
4.94/3.83
4.49
7
4.70/3.93e
4.84
8
c
9
4.38
4.43
4.62
0.84
0.87
0.85
0.95
0.79
0.94
10
11
5.07/4.20
4.46
5.00/3.88b
a
b
Measured in toluene-d8. AX pattern (2J H,H ) 11.8 Hz for 3
and 11.3 Hz for 11). c Not observed. Doublet. e Broad signal.
d
For compounds 3, 7, and 11, the values of δ(119Sn)
(Table 3) correspond to the five or better [4+2] coor-
dinated diphenyltin(IV) compounds (compare with
-26.7 ppm for Ph2SnCl2).15b Further forcing of the
Sn-O coordination is reflected in increasing of
values 1J (119Sn,13C(1)) and 1J (119Sn,13C(1′)) (-786.0
Hz for Ph2SnCl2).15b The calculated bonding angle
C(1)-Sn-C(1′) (136° (3), 133° (7), 130° (11)) permits the
prediction that the shape of the tin atom coordination
polyhedra going from the solid state is probably retained
in solution (compare with the bonding angles in the
crystal structures of these compounds). A 119Sn NMR
study of these compounds (temperature range 170-360
K) yielded parallel results to those obtained previously.
The dynamic behavior of 3, 7, and 11 has been studied
Solu tion NMR Stu d y. The 119Sn NMR shifts and
1J (119Sn,13C) coupling constants were shown to be very
sensitive indicators for elucidation of the coordination
numbers and geometries of organotin compounds.15
None of the compounds studied exhibited any concen-
tration dependences of the 119Sn NMR shifts, from which
it is clear that no intermolecular interactions are
present.
In tetraorganotin compounds 1, 5, and 9, a four-
coordinated tin atom without any or with very weak
Sn-O interaction is indicated by the values of δ(119Sn)
and particularly by the values of the 1J (119Sn,13C(1)) and
1J (119Sn,13C(1′)) coupling constants (see Table 3), which
differ only slightly from those for nonfunctional Ph4Sn
(-128.1 ppm, 531 Hz).15a The coordination geometry of
the central tin atom is a slightly distorted tetrahedron,
with bonding angles C(1)-Sn-C(1′) and C(1′)-Sn-C(1′)
of approximately 109°, 107° for 1; 107°, 106° for 5, and
107°, 106° for 9.15c Neither 1H NMR nor 119Sn NMR
exhibits any important temperature dependences in the
range studied (170-360 K, toluene-d8, see Table 4).
In compounds 2, 6, and 10, the values of δ(119Sn)
(see Table 3) (compare with -44.7 ppm for Ph3SnCl)15a
result in a higher coordination number for the tin
atom than four. The existence of a weak Sn-O inter-
action is reflected in an increase in the values of the
1
by variable-temperature H NMR (170-360 K, toluene-
1
d8). At room temperature, the H NMR spectrum again
displays sharp signals for all protons. When the tem-
perature is decreased, initially a broadeaning of the CH2
signal (for 3, 11) is observed, continuing in decoalescence
of the benzylic protons at 235 K for 3 and 190 K for 11.
These are visible as a sharp AX pattern, whereas the
signals of OR groups are seen as an unresolved signal
1
(singlet for Me in 3 and for t-Bu in 11). The H NMR
data of these compounds under decoalescence temper-
atures (235 K for 3 and 180 K for 11) can be explained
only by the geometry A (Scheme 2), which is similar to
those found in the solid state, with the two -CH2OR
units being equivalent. In each -CH2OR unit, the
benzylic protons are diastereotopic and can be seen as
an AX pattern. When the temperature is raised, the
benzylic protons become equivalent by Sn-O bond
dissociation followed by rotation about the C-C bond
(see B in Scheme 2). The activation energy for this
1
1J (119Sn,13C(1)) and J (119Sn,13C(1′)) coupling constants
(614.3 Hz for Ph3SnCl).15a The magnitudes of the
calculated bonding angles C(1)-Sn-C(1′) and C(1′)-
Sn-C(1′)15c (119°, 119° (2); 116°, 119° (6); and 118°, 118°
(10)) indicate similar structures as in the solid state (see
(14) Harris, R. K.; Sebald, A.; Furlani, D.; Tagliavini, G. Organo-
metallics 1988, 7, 388.
(15) (a) Holecˇek, J .; Na´dvorn´ık, M.; Handl´ırˇ, K.; Lycˇka, A. J .
Organomet. Chem. 1983, 241, 177. (b) Holecˇek, J .; Na´dvorn´ık, M.;
Handl´ırˇ, K.; Lycˇka, A. Collect. Czech. Chem. Commun. 1990, 55, 1193.
(c) Holecˇek, J .; Na´dvorn´ık, M.; Handl´ırˇ, K.; Lycˇka, A. Z. Chem. 1990,
30, 265. (d) Lycˇka, A.; Holecˇek, J .; Schneider, B.; Straka, J . J .
Organomet. Chem. 1990, 389, 29. (e) Pejchal, V.; Holecˇek, J .; Lycˇka,
A. Sci. Univ. Pap. Pardubice 1996, A2, 35; Chem. Abstr. 1997, 126,
317445.
(16) Handwerker, H.; Leis, C.; Probst, R.; Bassinger, P.; Grohmann,
A.; Kiprof, P.; Herdtweek, F.; Blu¨mel, J .; Auner, N.; Zybill, C.
Organometallics 1993, 12, 2162.
(17) Eyring equation: ∆Gq ) -RTc ln[2πh(∆ν)/kTx3] with ∆Gq
)
free energy of activation (J ), Tc ) coalescence temperature (K), and
∆ν ) chemical shift difference (Hz); the other symbols have their usual
meanings.

4002 Organometallics, Vol. 21, No. 19, 2002
J ambor et al.
The 119Sn, 13C, and 1H NMR spectra were acquired on
Bruker AMX360 or Avance500 spectrometers at 300 K in
CDCl3 or in toluene-d8 (range 360-170 K). Appropriate chemi-
Sch em e 2
1
cal shifts were calibrated on the H-residual peak of CHCl3 (δ
) 7.25 ppm) or toluene (δ ) 2.09 ppm), the 13C residual peak
of CHCl3 (δ ) 77.00 ppm) or toluene (δ ) 20.39 ppm), and
119Sn-external tetramethylstannane (δ ) 0.00 ppm). Chemical
shift data are provided in ppm, with coupling constants in Hz.
Abbreviations used are follows: s ) singlet; d ) doublet; t )
triplet; h ) heptet; m ) complex multiplet.
Solid state 119Sn spectra were recorded on a Bruker DSX
200 spectrometer equipped with a double-bearing CP/MAS
probe at room temperature. The 119Sn Hartmann-Hahn cross-
polarization match was set with tetracyclohexyl tin using a
1H 90° pulse of 4 µs. RAMP/CP/MAS (ramped/cross-polariza-
tion/magic angle spinning) experiments were used with a
repetition delay of 10 s and the contact time was set at 2 ms.
In each case, at least two spinning rates (4.5-9 kHz) were
used to identify the isotropic chemical shift. The number of
scans varied between 200 and 4000. For sample 2, the
repetition delay was set up at 30 s, as the 1H T1 relaxation
time was extremely long. Such a long relaxation delay indi-
cates very slow internal molecular motion resulting from
arrangement of molecules in the crystal cell. The 119Sn
chemical shifts were calibrated indirectly using tetracyclohexyl
tin (δ ) -97.35 ppm). The 119Sn NMR chemical shift was
allocated approximately to the center of gravity of the signal.
process is ∆Gq ) 41.9 kJ mol-1 for 3 and 31.9 kJ mol-1
for 11. Both the alkyl groups appear as one signal
because of the very fast rotation around the benzylic
carbon-oxygen axis.
The dynamic study of 7 has resulted in a different
dynamic process. When the temperature is decreased,
initially broadening of the CH2, CH, and CH3 signals is
observed, continuing in their decoalescence at 210 K,
and two rather broad signals for CH2, CH, and CH3
protons can be seen in 7. This dynamic process (similar
to that in compounds 2, 6, and 10) involves exchange
between the coordinated and noncoordinated ether
groups in 7 (∆Gq ) 38.0 kJ mol-1). The observation of
different decoalescence temperatures for 3, 7, and 11
can be explained in the same way as in the previous
case.
In the mass spectrometry, the positive-ion electrospray ioni-
zation (ESI) mass spectra were measured on an Esquire3000
ion trap analyzer (Bruker Daltonics, Bremen, Germany) in the
range m/z 100-1000, and negative-ion ESI mass spectra were
measured on the Platform quadrupole analyzer (Micromass,
UK) in the range m/z 15-600. The ion trap was tuned to give
an optimum response for m/z 500. The samples were dissolved
in acetonitrile and analyzed by direct infusion at a flow rate
of 1-3 µL/min. The selected precursor ions were further
analyzed by MS/MS analysis with an ion trap analyzer under
the following conditions: isolation width m/z ) 8, ion source
temperature 300 °C, flow rate and nitrogen pressure 4 L/min
and 10 psi. Two mechanisms are involved in the ionization
process of organotin compounds under ESI conditions. Simi-
larly to recently published results,18 the main process of the
ion formation is the cleavage of the most labile bond, i.e., AB
f [A]+ + [B]-. If the Sn-Cl bond is present in the structure,
then this bond is cleaved first, yielding two complementary
ions, [M - Cl]+ and [Cl]-. The cationic part of the molecule
[M - Cl]+ is mostly the base peak of the positive-ion ESI-MS
and can be further studied by MS/MS analysis. The anionic
part, [Cl]-, is measured in the negative-ion mode. For negative
ions with m/z lower than about 60, the quadrupole analyzer
has to be used instead of the ion trap for their detection (e.g.,
[Cl]- at m/z 35 and 37). When the Sn-Cl bond is missing in
the structure (1, 5, and 9), then the primary cleavage is Sn-
phenyl and the cationization with alkali metal ions as a
competitive ionization process can also occur. The formation
of adducts [M + Na]+ and [M + K]+ is observed in most cases
(the only process for 9), but the relative abundances of these
adducts are usually 1 order of magnitude lower than [R3Sn]+
ions. The adduct abundances depend on the amount of salts
in the samples and solvents used for their analysis. Two
compounds in our series contain three chlorine atoms (4 and
8) and both show unusual behavior during the analysis in the
ion trap. They react in the mass spectrometer according to the
equation M + M f M* () 2M - SnCl4) + SnCl4. All identified
ions in the spectra come from these condensed molecules
except for the ion [M - Cl]+ for 4 with the relative abundance
3% (see Experimental Section). The probable explanation for
Monoorganotin compounds 4 and 8 contain a [4+2]
coordinated tin atom, due to a relatively strong Sn-O
interaction (δ(119Sn) ) -270.5 (4) and -238.8 ppm (8),
1J (119Sn,13C(1)) ) 1372.2 (4) and 1036.2 (8) Hz, in
CDCl3) (-61.3 ppm and 1121.2 Hz for PhSnCl3).15e The
119Sn NMR shifts do not exhibit any temperature
dependence in the range studied (170-360 K in toluene-
d8), and the dynamic behavior of these compounds,
1
studied with variable-temperature H NMR (170-360
K, toluene-d8), exhibits a broadening of the CH2 signals,
but no signals were observed in the range 220-170 K.
Con clu sion
Eleven original organotin(IV) derivatives of a novel
type of oxygen-containing pincer ligand have been
prepared, and the structures were estimated in solution
and in the solid state for selected compounds. The
existence of an Sn-O coordination bond has been proven
using the NMR spectral parameters. The relation of the
strength of the Sn-O interaction to different bulkiness
of the ligands is evident in the values of δ(119Sn), of the
coupling constants in solution, and of the Sn-O bond
lengths. Different temperatures of decoalescence (CH2
signals in the 1H NMR spectrum) are also proof of
variable strength of the Sn-O interaction. Determina-
tion of the crystal structures reveals the similarity of
the shapes of coordination polyhedra, differing mutually
from ideal arrangement only in the extent of the
declinations. In all crystal structures, the oxygen donor
groups are bound to the tin atom in cis fashion, resulting
in a pseudofacial O,C,O-coordination mode of the “pin-
cer” ligands.
Exp er im en ta l Section
Gen er a l Meth od s. Solvents were dried by standard meth-
ods and distilled prior to use. All moisture- and air-sensitive
reactions were carried out under an argon atmosphere using
standard Schlenk techniques.
(18) Ru˚zˇicˇka, A.; Dosta´l, L.; J ambor, R.; Buchta, V.; Brus, J .;
C´ısarˇova´, I.; Holcˇapek, M.; Holecˇek, J . Appl. Organomet. Chem. 2002,
16, 315.

Organotin(IV) Derivatives of O,C,O-Chelating Ligands
Organometallics, Vol. 21, No. 19, 2002 4003
this phenomenon is a long reaction time in the ion trap
analyzer (in the range of milliseconds) compared to other mass
analyzers.
Com p ou n d P r ep a r a tion . Starting materials 1-bromo-2,6-
bis(bromomethyl)benzene,19 1-bromo-2,6-bis(methoxymethyl)-
benzene (L1Br),19 and 1-bromo-2,6-bis(isopropoxymethyl)-
benzene (L2Br)20 were prepared analogously to the literature
procedures. The compounds L1Li and L2Li were prepared in
situ (see below).
g (5.68 mmol) of Ph2SnCl2, 1.72 g (5.68 mmol) of PhSnCl3, and
1.48 g (5.68 mmol) of SnCl4.
Com p ou n d 2. Yield: 2.3 g (81%), mp 185-190 °C. Anal.
Calcd for C22H23ClO2Sn (MW 473.56): C, 55.80; H, 4.90.
Found: C, 55.50; H, 4.75. MW ) 474. MS: m/z 513, 3%, [M +
K]+; m/z 497, 3%, [M + Na]+; m/z 439, 100%, [M - Cl]+. 1H
NMR (CDCl3, 360 MHz): δ (ppm) 2.96 (s, 6H, CH3), 4.54 (s,
n
4H, CH2, J (119Sn,1H ) 7.9 Hz)), 7.20-7.75 (complex pattern,
13H, SnPh2, SnC6H3). 13C NMR (CDCl3, 90 MHz): δ (ppm) 57.6
1
Syn th esis of 1-Br om o-2,6-bis(ter t-bu toxym eth yl)ben -
zen e (L3Br ). A solution of 1-bromo-2,6-bis(bromomethyl)-
benzene in 20 mL of benzene (3.11 g, 9.07 mmol) was added
to the stirred suspension of potassium tert-butoxide (3.04 g,
27.2 mmol) in 30 mL of benzene; the solution was stirred for
a further 2 h. This solution was hydrolyzed by 10 mL of water,
and the aqueous phase was washed with 20 mL of benzene.
Benzene extracts were combined and dried over anhydrous
sodium sulfate. The yellowish solution was filtered, the
benzene filtrate was evaporated, and a pale yellow oil re-
mained, which was distilled to give 1.7 g (57.4%) of L3Br as a
colorless oil, bp 95-100 °C/20 Pa. Anal. Calcd for C16H25BrO2
(CH3), 74.1 (CH2), SnC6H3, 135.3 (C(1), J (119Sn,13C) ) 729.6
Hz), 126.8, 129.1, 146.0; SnPh2, 142.4 (C′(1), 1J (119Sn,13C) )
733.9 Hz), 128.4, 128.9, 135.4.
Com p ou n d 3. Yield: 2.4 g (92%), mp 188-192 °C. Anal.
Calcd for C16H18Cl2O2Sn (MW 431.91): C, 44.49; H, 4.20.
Found: C, 44.10; H, 4.20. MW ) 432. MS: m/z 471, 12%, [M
+ K]+; m/z 455, 20%, [M + Na]+; m/z 397, 100%, [M - Cl]+.
1H NMR (CDCl3, 360 MHz): δ (ppm) 3.17 (s, 6H, CH3), 4.68
(s, 4H, CH2, nJ (119Sn,1H) ) 10.8 Hz), 7.18-7.81 (complex
pattern, 8H, SnPh, SnC6H3). 13C NMR (CDCl3, 90 MHz): δ
(ppm) 57.9 (CH3), 73.1 (CH2), SnC6H3, 134.7 (C(1), 1J (119Sn,13C)
) 997.4 Hz), 126.3, 130.2, 144.9; SnPh, 141.1 (C′(1), 1J (119Sn,13C)
) 1027.2 Hz), 129.2, 130.6, 134.7.
1
(MW 329.29): C, 58.36; H, 7.65. Found: C, 58.16; H, 7.44. H
NMR (CDCl3, 360 MHz): δ (ppm) 1.31 (s, 18H, CH3), 4.51 (s,
4H, CH2), 7.30 (t, 1H, Ar-H), 7.45 (d, 2H, Ar-H). 13C NMR
(CDCl3, 90 MHz): δ (ppm) 27.6 (CH3), 63.8 (CH2), 73.6
(OCMe3), C6H3 (not assigned) 121.9, 126.9, 127.3, 139.4.
Syn th esis of 2,6-Bis(ter t-bu toxym eth yl)p h en yllith iu m
(L3Li). A 1.1 mL sample of n-BuLi (2.008 M) was added to
the stirred solution of L3Br (0.66 g, 2 mmol) in 10 mL of hexane
at ambient temperature; the solution was stirred for a further
1 h. The solution was concentrated to 5 mL and left to
crystallize overnight. The white solid was filtrated at -78 °C
and washed with 3 mL of precooled pentane to give pure L3Li
in 89% yield. 1H NMR (toluene-d8, 360 MHz): δ (ppm) 1.15
(s, 18H, CH3), 4.29 (s, 4H, CH2), 7.18 (m, 3H, Ar-H).
Com p ou n d 4. Yield: 1.1 g (47%), mp 75-80 °C. Anal. Calcd
for C10H13Cl3O2Sn (MW 390.26): C, 30.78; H, 3.36. Found: C,
30.48; H, 3,05. MW ) 390. MW* ) 2 × M - SnCl4 ) 520. MS:
m/z 485, 100%, [M* - Cl]+; m/z 455, 8%, [M* - Cl - CH2O]+;
m/z 355, 3%, [M - Cl]+. MS/MS of 485 (collision amplitude 1
V): m/z 455, 94%, [M* - Cl-CH2O]+; m/z 425, 33%, [M* - Cl
- 2 × CH2O]+; m/z 395, 8%, [M* - Cl - 3 × CH2O]+; m/z 365,
8%, [M* - Cl - 4 × CH2O]+; m/z 349, 8%, [M* - Cl - 3 ×
CH2O - CH3OCH3]+; m/z 285, 19%, [C6H3(CH2OCH3)2Sn]+; m/z
255, 7%, [285 - CH2O]+; m/z 223, 8%, [285 - CH2O -
CH3OH]+; m/z 205, 100%, [CH3SnCl2]•+; m/z 192, 85%,
1
[H2SnCl2]•+. H NMR (CDCl3, 360 MHz): δ (ppm) 3.58 (s, 6H,
n
CH3), 4.68 (s, 4H, CH2, J (119Sn,1H) ) 12.35 Hz), 7.23 (d, 2H,
Syn th esis of P h 3Sn L1 (1). A 3.3 mL portion of n-BuLi
(2.008 M) was added to the stirred solution of L1Br (1.47 g,
5.98 mmol) in 15 mL of Et2O at -78 °C; the solution was
stirred for a further 2 h at this temperature, followed by
dropwise addition to a precooled (-78 °C) 20 mL suspension
of hexane containing 2.2 g (5.68 mmol) of Ph3SnCl. After
addition, the solution faded to pale yellow. The mixture was
stirred for a further 2 h, and then the solvent was evaporated
in vacuo and the residue was dissolved in CHCl3. After the
resulting solid was filtered off, the CHCl3 filtrate was concen-
trated, layered with pentane, and left to crystallize to 1, which
was obtained as a white solid. Yield: 2.1 g (68%), mp 87-95
°C. Anal. Calcd for C28H28O2Sn (MW 515.21): C, 65.27; H, 5.48.
Found: C, 67.01; H, 5.14. MW ) 516. MS: m/z 477, 9%, [M +
K - C6H6]+; m/z 461, 11%, [M + Na - C6H6]+; m/z 439, 100%,
[M - C6H5]+. MS/MS of 439 (collision amplitude 1 V): m/z 407,
SnC6H3), 7.43 (t, 1H, SnC6H3). 13C NMR (CDCl3, 90 MHz): δ
(ppm) 56.9 (CH3), 73.6 (CH2), SnC6H3, 133.3 (C(1), 1J (119Sn,13C)
) 1372.2 Hz), 125.7, 129.9, 142.9.
Syn th esis of P h 3Sn L2 (5). A 2.76 mL sample of n-BuLi
(2.008 M) was added to the stirred solution of L2Br (1.67 g,
5.54 mmol) in 15 mL of hexane at RT; the solution was stirred
for a further 3 h at this temperature, followed by dropwise
addition to a 10 mL suspension of hexane containing 2.03 g
(5.27 mmol) of Ph3SnCl. After addition, the solution faded to
pale yellow. The mixture was stirred for a further 5 h, and
then the solvent was evaporated in vacuo and the residue was
dissolved in CHCl3. After the resulting solid was filtered off,
the CHCl3 filtrate was concentrated, layered with pentane, and
left to crystallize to 5, which was obtained as a white solid.
Yield: 2.2 g (70%). Anal. Calcd for C32H36O2Sn (MW 571.32):
C, 67.27; H, 6.35. Found: C, 66.91; H, 6.14. MW ) 572. MS:
10%, [M - C6H5 - CH3OH]+; m/z 377, 95%, [M - C6H5
-
m/z 495, 100%, [M - C6H5]+; m/z 453, 7%, [M - C6H5
-
CH3OH - CH2O]+; m/z 375, 100%, [M - C6H5 - 2 × CH3OH]+;
m/z 347, 15%, [M - C6H5 - 2 × CH3OCH3]+; m/z 299, 4%, [M
- C6H5 - CH3OH - CH2O - C6H6]+; m/z 255, 22%, [M - C6H5
- 2 × CH3OH - Sn]+; m/z 197, 7%, [C6H5Sn]+; m/z 179, 6%,
[M - C6H5 - 2 × CH3OH - Sn - C6H4]+; m/z 165, 4%,
[C6H3(CH2OCH3)2]+. 1H NMR (CDCl3, 360 MHz): δ (ppm) 2.69
(s, 6H, CH3), 4.16 (s, 4H, CH2, nJ (119Sn,1H) ) 5.1 Hz), 7.23-
7.65 (complex pattern, 18H, SnPh3, SnC6H3). 13C NMR (CDCl3,
90 MHz): δ (ppm) 57.0 (CH3), 75.4 (CH2), SnC6H3, 137.2 (C(1),
1J (119Sn,13C) ) 570.8 Hz), 128.0, 128.7, 146.9; SnPh3, 142.4
propene]+. MS/MS of 495 (collision amplitude 0.9 V): m/z 453,
100%, [M - C6H5 - propene]+; m/z 411, 15%, [M - C6H5 - 2
× propene]+; m/z 393, 11%, [M - C6H5 - propene - 2-pro-
panol]+; m/z 351, 23%, [(C6H6)3Sn]+; m/z 315, 45%, [M - C6H5
- C6H6 - propene - 2-propanol]+; m/z 179, 39%, [C6H3C6H3-
CH3(CH2)]+. 1H NMR (CDCl3, 360 MHz): δ (ppm) 0.85 (d, 12H,
n
CH3), 3.14 (h, 2H, OCH), 4.34 (s, 4H, CH2, J (119Sn,1H) ) 6.6
Hz), 7.27-7.68 (complex pattern, 18H, SnPh3, SnC6H3). 13C
NMR (CDCl3, 90 MHz): δ (ppm) 22.1 (CH3), 70.7 (OCH) 71.9
(CH2), SnC6H3, 135.5 (C(1), 1J (119Sn,13C) ) 542.4 Hz), 127.2,
129.4, 147.3; SnPh3, 141.5 (C′(1), 1J (119Sn,13C) ) 527.1 Hz),
128.3, 128.6, 136.8.
1
(C(1′), J (119Sn,13C) ) 543.1 Hz), 127.9, 128.1, 136.8.
Syn th esis of P h 2ClSn L1 (2), P h Cl2Sn L1 (3), a n d Cl3Sn L1
(4). A procedure similar to that for 1 was followed. The
precooled (-78 °C) 20 mL suspension of hexane contained 1.95
Syn th esis of P h 2ClSn L2 (6), P h Cl2Sn L2 (7), a n d Cl3Sn L2
(8). A procedure similar to that for 5 was followed. The 10
mL suspension of hexane contained 1.81 g (5.26 mmol) of Ph2-
SnCl2, 1.59 g (5.26 mmol) of PhSnCl3, and 1.37 g (5.26 mmol)
of SnCl4.
(19) Markies, P. R.; Altink R. M.; Villena A.; Akkerman O. S.;
Bickelhaupt F.; Smeets W. J . J .; Spek A. L. J . Organomet. Chem. 1991,
402, 289.
(20) Ortiz, B.; Walls, F.; Barrios, H.; Obregon, S. R.; Pinelo, L. Synth.
Commun. 1993, 6, 749.
Com p ou n d 6. Yield: 2.5 g (85%), mp 65-70 °C. Anal. Calcd
for C26H31ClO2Sn (MW 529.67): C, 58.96; H, 5.90. Found: C,

4004 Organometallics, Vol. 21, No. 19, 2002
J ambor et al.
58.60; H, 5.60. MW ) 530. MS: m/z 495, 100%, [M - Cl]+;
m/z 453, 4%, [M - Cl - propene]+. MS/MS of 495 (collision
amplitude 1 V): m/z 453, 100%, [M - Cl - propene]+; m/z 411,
22%, [M - Cl - 2 × propene]+; m/z 393, 8%, [M - Cl - propene
- 2-propanol]+; m/z 351, 18%, [(C6H5)3Sn]+; m/z 315, 55%, [M
- Cl - C6H6 - propene - 2-propanol]+; m/z 239, 8%, [M - Cl
- C6H6 - propene - 2-propanol - C6H4]+; m/z 195, 3%, [M -
Cl - C6H6 - propene - 2-propanol - Sn]+; m/z 179, 25%,
[HOCH2C6H3CH2OCH(CH3)2]+. 1H NMR (CDCl3, 360 MHz): δ
(ppm) 0.80 (d, 12H, CH3), 3.53 (h, 2H, OCH), 4.63 (s, 4H, CH2),
7.24-7.75 (complex pattern, 13H, SnPh2, SnC6H3). 13C NMR
(CDCl3, 90 MHz): δ (ppm) 21.1 (CH3), 71.9 (OCH) 69.3 (CH2),
SnC6H3, 134.2 (C(1), 1J (119Sn,13C) ) 683.8 Hz), 127.1, 129.6,
146.9; SnPh2, 143.2 (C′(1), 1J (119Sn,13C) ) 737.9 Hz), 128.4,
129.2, 135.6.
1H NMR (CDCl3, 360 MHz): δ (ppm) 0.94 (s, 18H, CH3), 4.62
(s, 4H, CH2,), 7.27-7.80 (complex pattern, 15H, SnPh2, SnC6H3).
13C NMR (CDCl3, 90 MHz): δ (ppm) 27.4 (CH3), 65.7 (CH2),
1
75.6 (OCMe3), SnC6H3, 134.2 (C(1), J (119Sn,13C) ) 714.4 Hz),
1
126.4, 129.8, 147.8; SnPh2, 143.3 (C′(1), J (119Sn,13C) ) 720.6
Hz), 128.5, 129.3, 135.6.
Com p ou n d 11. Yield: 2.02 g (93%), mp 112-115 °C. Anal.
Calcd for C22H30Cl2O2Sn (MW 516.07): C, 51.20; H, 5.86.
Found: C, 51.55; H, 6.12. MW ) 516. MS: m/z 555, 15%, [M
+ K]+; m/z 539, 32%, [M + Na]+; m/z 519, 7%, [M + K - HCl]+;
m/z 503, 6%, [M + Na - HCl]+; m/z 481, 100%, [M - Cl]+; m/z
425, 54%, [M - Cl - isobutene]+; m/z 369, 58%, [M - 2 ×
isobutene]+. 1H NMR (CDCl3, 360 MHz): δ (ppm) 0.98 (s, 18H,
CH3), 4.69 (s, 4H, CH2, nJ (119Sn,1H) ) 8.8 Hz), 7.16-7.72
(complex pattern, 8H, SnPh, SnC6H3). 13C NMR (CDCl3, 90
MHz): δ (ppm) 27.3 (CH3), 64.6 (CH2), 77.7 (OCMe3), SnC6H3,
132.1 (C(1), 1J (119Sn,13C) ) 872.4 Hz), 127.1, 130.6, 146.8;
SnPh, 144.6 (C′(1), 1J (119Sn,13C) ) 945.9 Hz), 128.6, 130.6,
135.3.
Attem p t to P r ep a r e Cl3Sn L3. All attempts to prepare this
compound result only in a mixture of unseparable products.
The NMR tube experiment at 200 K revealed no reaction
during 20 min after the addition of SnCl4 (132 mg, 0.5 mmol)
to the toluene solution of L3Li (130 mg, 0.5 mmol). After this
period, the NMR tube was allowed to warm to 260 K and the
reaction proceeded, resulting in the same mixture of products.
The GC-MS analysis of the vapor over the sample solution
indicated the presence of di(tert-butyl) ether, tert-butylmethyl
ether, tert-butyl acetate, and benzene. The precipitating non-
soluble solid was identified as LiCl.
Cr ysta llogr a p h y. Crystals suitable for X-ray structure
determination were obtained by vapor diffusion of n-hexane
into the 5% dichloromethane solution for compounds 1, 2, 3,
4, and 7, respectively, and by crystallization of 11 from chloro-
form solution. Data for all the colorless crystals were collected
at 150(2) K on a Nonius KappaCCD diffractometer using Mo
KR radiation (λ ) 0.71073 Å), with a graphite monochromator.
The structures were solved by direct methods (SIR92). All
reflections were used in the structure refinement based on F2
by the full-matrix least-squares technique (SHELXL97). The
hydrogen atoms were mostly localized on a difference Fourier
map; however, to ensure uniformity of treatment of all crystals,
all the hydrogens were recalculated into idealized positions
(riding model) and assigned temperature factors Hiso(H) )
1.2Ueq(pivot atom) or 1.5Ueq for the methyl moiety. Absorption
corrections were carried out using the multiscan procedure
(SORTAV). It follows from the last cycle of refinement of all
the structures that (∆/δ)max < 0.003. Crystallographic data for
individual structures are summarized in Table 1. A full list of
crystallographic data and parameters including fractional
coordinates are deposited under CCDC 183103 (1), 183104 (2),
183105 (3), 183106 (4), 183107 (7), and 183108 (11), at the
Cambridge Crystallographic Data Center, 12 Union Road,
Cambridge, CB2 1EZ, UK [Fax: int. code + 44(1223)336-033;
E-mail: deposit@ccdc.cam.ac.uk].
Com p ou n d 7. Yield: 2.4 g (90%), mp 135-137 °C. Anal.
Calcd for C20H26Cl2O2Sn (MW 488.02): C, 49.22; H, 5.37.
Found: C, 48.92; H, 5.20. MW ) 488. MS: m/z 527, 23%, [M
+ K]+; m/z 511, 6%, [M + Na]+; m/z 453, 100%, [M - Cl]+; m/z
1
411, 3%, [M - Cl - propene]+. H NMR (CDCl3, 360 MHz): δ
(ppm) 0.89 (d, 12H, CH3), 3.75 (h, 2H, OCH), 4.72 (s, 4H, CH2,
nJ (119Sn,1H ) 9.1 Hz)), 7.20-7.80 (complex pattern, 8H, SnPh,
SnC6H3). 13C NMR (CDCl3, 90 MHz): δ (ppm) 21.3 (CH3), 73.0
1
(OCH) 67.8 (CH2), SnC6H3, 132.9 (C(1), J (119Sn,13C) ) 930.5
Hz), 127.1, 130.8, 146.1; SnPh, 143.4 (C′(1), 1J (119Sn,13C) )
996.1 Hz), 128.9, 130.4, 135.4.
Com p ou n d 8. Yield: 0.9 g (39%), mp 68-72 °C. Anal. Calcd
for C14H21Cl3O2Sn (MW 446.36): C, 37.67; H, 4.74. Found: C,
37.97; H, 4.95. MW ) 446. MW* ) 2 × M - SnCl4 ) 632. MS:
m/z 655, 3%, [M* + Na]+; m/z 597, 100%, [M* - Cl]+; m/z 519,
10%, [M* - Cl - HCl - propene]+; m/z 477, 1%, [M* - Cl -
HCl - 2 × propene]+. MS/MS of 597 (collision amplitude 0.6
V): m/z 519, 100%, [M* - Cl - HCl - propene]+; m/z 477,
50%, [M* - Cl - HCl - 2 × propene]+; m/z 435, 32%, [M* -
Cl - HCl - 3 × propene]+; m/z 393, 20%, [M* - Cl - HCl -
4 × propene]+; m/z 375, 7%, [M* - Cl - HCl - 4 × propene -
H2O]+. 1H NMR (CDCl3, 360 MHz): δ (ppm) 1.34 (d, 12H, CH3),
n
4.32 (h, 2H, OCH), 4.73 (s, 4H, CH2, J (119Sn,1H) ) 11.1 Hz),
7.25 (d, 2H, SnC6H3), 7.42 (t, 1H, SnC6H3). 13C NMR (CDCl3,
90 MHz): δ (ppm) 21.7 (CH3), 72.4 (OCH) 69.7 (CH2), SnC6H3,
1
139.6 (C(1), J (119Sn,13C) ) 1036.2 Hz), 126.9, 130.0, 145.3.
Syn th esis of P h 3Sn L3 (9). A 1.2 g (4.7 mmol) portion of
L3Li in hexane was added dropwise to a stirred suspension of
1.8 g (4.7 mmol) of Ph3SnCl in 10 mL of hexane. After addition,
the solution was heated for 5 h at 60 °C and then stirred
overnight. Then the solvent was evaporated in vacuo and the
residue was dissolved in CHCl3. After the resulting solid was
filtered off, the CHCl3 filtrate was concentrated, covered with
pentane, and left to crystallize to 9, which was obtained as a
white solid. Yield: 2.67 g (95%), mp 155-157 °C. Anal. Calcd
for C34H40O2Sn (MW 599.38): C, 68.13; H, 6.73. Found: C,
67.91; H, 6.51. MW ) 600. MS: m/z 639, 70%, [M + K]+; m/z
1
623, 100%, [M + Na]+. H NMR (CDCl3, 360 MHz): δ (ppm)
0.96 (s, 18H, CH3), 4.39 (s, 4H, CH2, nJ (119Sn,1H) ) 7.7 Hz),
7.41-7.78 (complex pattern, 18H, SnPh3, SnC6H3). 13C NMR
(CDCl3, 90 MHz): δ (ppm) 27.2 (CH3), 67.0 (CH2), 73.4
(OCMe3), SnC6H3, 133.6 (C(1), 1J (119Sn,13C ) 536.1 Hz), 125.9,
129.7, 147.9; SnPh3, 141.4 (C′(1), 1J (119Sn,13C ) 520.9 Hz),
128.5, 128.7, 136.8.
Ack n ow led gm en t. The authors wish to thank the
Grant Agency of the Czech Republic (grants nos. 203/
00/0920, 203/99/M037) and The Ministry of Education
of the Czech Republic (LN00A028 project) for financial
support.
Syn th esis of P h 2ClSn L3 (10) a n d P h Cl2Sn L3 (11). A
procedure similar to that in 9 was followed, without the
heating, and the solutions were stirred for only 3 h, after the
Li salt was added into the hexane solution. The 10 mL
suspension of hexane contained 2.4 g (7 mmol) of Ph2SnCl2
and 1.27 g (4.2 mmol) of PhSnCl3.
Com p ou n d 10. Yield: 3.52 g (90%), mp 118-123 °C. Anal.
Calcd for C28H35ClO2Sn (MW 557.72): C, 60.30; H, 6.33.
Found: C, 60.55; H, 6.62. MW ) 558. MS: m/z 523, 100%, [M
- Cl]+; m/z 495, 2%, [M - Cl - ethene]+; m/z 467, 15%, [M -
Cl - isobutene]+; m/z 411, 10%, [M - Cl - 2 × isobutene]+.
Su p p or tin g In for m a tion Ava ila ble: Tables of all crystal
data and structure refinement, atomic coordinates, anisotropic
displacement parameteres, and geometric data for compounds
1-4, 7, and 11. This material is available free of charge via
the Internet at http://pubs.acs.org.
OM020361I