Unsymmetrical Bicentric Organotin Lewis Acids {Me2N(CH2)3}Ph(X)Sn(CH2)nSnPh2X (X = F, I; N = 1, 3): Syntheses and Structures

Article abstract of DOI:10.1021/acs.organomet.6b00500

The syntheses of the intramolecularly coordinated organotin compounds {Me₂N(CH₂)₃}Ph(X)SnCH₂SnPh₂X (3, X = I; 4, X = F) and {Me₂N(CH₂)₃}Ph(F)Sn(CH₂)₃SnPh₂F (7) are reported. The compounds have been characterized by elemental analysis, electrospray mass spectrometry, ¹H,¹H DOSY (4), ¹³C, ¹⁹F, and ¹¹⁹Sn NMR spectroscopy, and single-crystal X-ray diffraction analysis. In the solid state, compound 4 is a head-to-tail dimer as a result of unsymmetrical Sn-F-Sn bridges, whereas compound 7 is a monomer with F→Sn intramolecular coordination, giving a six-membered ring. In solution, both 4 and 7 are monomeric. The reactions of both 4 and 7 with fluoride anion in CD₂Cl₂ have been investigated by variable-temperature ¹⁹F and ¹¹⁹Sn NMR spectroscopy.

Full text of DOI:10.1021/acs.organomet.6b00500

Article
pubs.acs.org/Organometallics
Unsymmetrical Bicentric Organotin Lewis Acids
{Me2N(CH2)3}Ph(X)Sn(CH2)nSnPh2X (X = F, I; n = 1, 3): Syntheses and
Structures
Nour Alashkar, Christina Dietz, Samer Baba Haj, Wolf Hiller, and Klaus Jurkschat*
Lehrstuhl fur Anorganische Chemie II, Technische Universitat Dortmund, 44221 Dortmund, Germany
̈
̈
S
* Supporting Information
ABSTRACT: The syntheses of the intramolecularly coordinated organotin
compounds {Me2N(CH2)3}Ph(X)SnCH2SnPh2X (3, X = I; 4, X = F) and
{Me2N(CH2)3}Ph(F)Sn(CH2)3SnPh2F (7) are reported. The compounds have
1
been characterized by elemental analysis, electrospray mass spectrometry, H,1H
DOSY (4), 13C, 19F, and 119Sn NMR spectroscopy, and single-crystal X-ray
diffraction analysis. In the solid state, compound 4 is a head-to-tail dimer as a
result of unsymmetrical Sn−F−Sn bridges, whereas compound 7 is a monomer
with F→Sn intramolecular coordination, giving a six-membered ring. In solution,
both 4 and 7 are monomeric. The reactions of both 4 and 7 with fluoride anion in CD2Cl2 have been investigated by variable-
temperature 19F and 119Sn NMR spectroscopy.
solubility of these compounds as with many other fluoridoor-
ganotin compounds precludes their practical applications. One
strategy to overcome this problem and to solubilize organotin
fluorides is the employment of intramolecularly coordinating
built-in ligands such as the 3-(dimethylamino)propyl sub-
stituent, [Me2N(CH2)3].7,8 In continuation of our studies
mentioned above we report herein the syntheses and molecular
structures of the fluorido-substituted organotin compounds
{Me2N(CH2)3}Ph(F)SnCH2SnPh2F, 4, and {Me2N(CH2)3}-
Ph(F)Sn(CH2)3SnPh2F, 7, containing the 3-(dimethylamino)-
propyl substituent. Also reported are 19F and 119Sn NMR
spectroscopic studies of the reactions of 4 and 7 with
tetraethylammonium fluoride dihydrate, NEt4F·2H2O, in
CD2Cl2 solution.
INTRODUCTION
■
The selective complexation of anions by all sorts of host
molecules remains a hot topic in contemporary chemistry. The
progress made in this field is demonstrated in regular
reviews.1a−k Although the topic is still dominated by organic
receptors, organometallic compounds also receive increasing
attention in this domain.2a−m In this context, we focused on the
complexation behavior of spacer-bridged ditin compounds as
bicentric Lewic acids toward different anions.2n We demon-
strated the potential of bis(haloorganylstannyl)methanes of the
type [RnX(3−n)Sn]2CH2 as ionophores in ion-selective electro-
des.2o An elegant example is bis(fluorido-di-n-octylstannyl)-
methane, [(n-C8H17)2SnF]2CH2,3 A (Chart 1), which showed
Chart 1. Selected Bicentric Tin-Based Lewis Acids Having
Potential as Anion Carriers
RESULTS AND DISCUSSION
■
Syntheses of 1−4 and Molecular Structures in the
Solid State. The reaction of the triorganotin iodide {Me2N-
(CH2)3}Ph2SnI8 with triphenylstannylmethylmagnesium bro-
mide, Ph3SnCH2MgBr,9 in THF gave {Me2N(CH2)3}-
Ph2SnCH2SnPh3, 1, in moderate yield (Scheme 1).
The reactions of compound 1 with 1 or 2 molar equiv of
elemental iodine in CH2Cl2 afforded the corresponding iodine-
substituted compounds {Me2N(CH2)3}Ph(I)SnCH2SnPh3, 2,
and {Me2N(CH2)3}Ph(I)SnCH2SnPh2I, 3, in good and
quantitative yields, respectively (Scheme 1). The reaction of
compound 3 with an excess of potassium fluoride (KF) in a
mixture of CH2Cl2 and water provided the organotin fluoride
{Me2N(CH2)3}Ph(F)SnCH2SnPh2F, 4, in moderate yield
(Scheme 1).
good results as an ionophore for a fluoride-anion-selective
electrode. Other examples are bis(dibromidophenylstannyl)-
methane, (PhSnBr2)2CH2,4 B (Chart 1), which exhibits
excellent selectivity toward phosphate anions, and bis-
(dichloridoorganostannyl)methane, {(RCl2Sn)2CH2, R = (4-
n-C8H17-C6H4)},5 C (Chart 1), which was shown to be a highly
selective arsenate ionophore.
Previously, we have reported the complexation reactions of
bis(halodiphenylstannyl)alkanes, (Ph2XSn)2(CH2)n (X = I, Br,
Cl, F; n = 1, 2, 3),6 with different halide anions and found that
bis(fluoridodiphenylstannyl)alkanes always preferentially che-
late fluoride anions over chloride or bromide. However, the low
Received: June 17, 2016
© XXXX American Chemical Society
A
DOI: 10.1021/acs.organomet.6b00500
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
Scheme 1. Syntheses of the Organotin Compounds 1−4
Compounds 2 and 3 are light yellowish solids, whereas
compound 4 is a white solid. They show good solubility in
CHCl3, CH2Cl2, and acetone.
Figure 2. General view (SHELXTL) of a molecule of 3 showing 30%
probability displacement ellipsoids and the crystallographic numbering
scheme. Hydrogen atoms are omitted for clarity.
Single crystals of compounds 2 and 3 suitable for X-ray
diffraction analyses were each obtained by slow evaporation of
the solvent from the corresponding solution in CH2Cl2/n-
hexane at room temperature. Those for 4 were obtained by
keeping a solution of the compound in acetone at −5 °C.
Compounds 2, 3, and 4 crystallize in the monoclinic space
groups P21/c, C2/c, and P21/n, respectively. The molecular
structures of 2−4 are presented in Figures 1−3, and selected
interatomic distances and angles are listed in Table 1.
Figure 3. General view (SHELXTL) of a molecule of 4 showing 30%
probability displacement ellipsoids and the crystallographic numbering
scheme. Hydrogen atoms are omitted for clarity.
close to the corresponding angles in A (167.9(1)°) and B
(169.4(3)°).
Figure 1. General view (SHELXTL) of a molecule of 2 showing 30%
probability displacement ellipsoids and the crystallographic numbering
scheme. There is a disorder of the phenyl ring C(41) to C(46) with
iodine I(2) (I2 is not shown; see Experimental Section) with a ratio of
90:10. Hydrogen atoms are omitted for clarity.
The environments at Sn(2) in compounds 2 and 3 are
distorted tetrahedral, with angles varying between 105.15(15)°
(C(41)−Sn(2)−C(21)) and 114.07(16)° (C(21)−Sn(2)−
C(31)) in 2 and between 103.77(9)° (C(31)−Sn(2)−I(2))
and 114.67(14)° (C(1)−Sn(2)−C(21)) in 3. As expected, the
Sn(2)−I(2) distance of 2.7050(5) Å in 3 is shorter than the
Sn(1)−I(1) distances in 2 and 3, as mentioned above.
Compound 4 forms a centrosymmetric head-to-tail dimer via
unsymmetrical Sn(1)−F(1)−Sn(2A) bridges at distances of
2.1229(17) and 2.2291(17) Å. These distances are comparable
with those reported for the organofluorido stannate complexes
NEt4[CH2(SnXPh2)2·F] (X = F, Br, I) ranging between
2.204(2) and 2.274(5) Å.6 Both tin atoms in 4 are
pentacoordinated and exhibit distorted trigonal-bipyramidal
geometries (geometric goodness ΔΣ(θ) = 88.2° for Sn1 and
81.1° for Sn2) with the equatorial positions being occupied by
three carbon atoms (C(1), C(2), and C(11) at Sn1, C(1),
C(21), and C(31) at Sn2). The axial positions are occupied by
The Sn(1) atoms in compounds 2 and 3 are each
pentacoordinated and exhibit a distorted trigonal-bipyramidal
environment (geometric goodness ΔΣ(θ) = 83.1° for 2 and 3)
with C(1), C(2), and C(11) occupying the equatorial and N(1)
and I(1) the axial positions. The Sn(1)−N(1) interatomic
distances of 2.486(4) (2) and 2.433(3) Å (3) are shorter than
the corresponding distance in compound Me2N(CH2)3SnPh2I
(A) of 2.541(5) Å8 and longer than that in Me2N-
(CH2)3SnMe2I (B) of 2.38(1) Å.10 The Sn(1)−I(1) distances
of 2.9777(4) (2) and 2.9613(4) Å (3) are between the
corresponding distances in compounds A and B of 2.888(0)
and 3.0567(6) Å, respectively. The N(1)−Sn(1)−I(1) angles in
2 and 3 of 164.51(8)° and 169.76(9)°, respectively, are rather
B
DOI: 10.1021/acs.organomet.6b00500
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
A
119Sn NMR spectrum of 2 showed two equally intense
Table 1. Selected Interatomic Distances (Å) and Angles
resonances (total integral 90) at δ −86 ppm (SnPh3) and δ −92
ppm (Sn{(CH2)3NMe2}PhI). In addition to that, two equally
intense resonances at δ −54 ppm and δ −102 ppm (integral
10) were observed. The two latter resonances are related to
SnIPh2 and Sn{(CH2)3NMe2}PhI, respectively, in 3 (see Sn2
and Sn1 in Figure 2). The assignments are supported by
comparison with the chemical shifts reported for (Ph3Sn)2CH2
(δ −79 ppm) and (IPh2Sn)2CH2 (δ −68 ppm), respectively.13
Furthermore, the 13C NMR chemical shifts of the SnCH2CH2
carbon atoms in the organotin iodides 2 and 3 at δ 19.1 and
18.7 ppm, respectively, are close to those reported for the
corresponding carbon atoms in Me2N(CH2)3SnPh2I (δ 18.5
ppm).8 These data reveal the SnPh3 and SnIPh2 tin atoms in 2
and 3 to be four- and the Sn{(CH2)3NMe2}PhI tin atoms in
both compounds to be five-coordinated. This view is further
supported by comparison of the 119Sn NMR chemical shifts of
Sn{(CH2)3NMe2}PhI in the organotin iodides 2 (δ −92 ppm)
and 3 (δ −102 ppm) with those for Me2PhSnI (δ −18 ppm)14
and {2-(Me2NCH2)C6H4}Me2SnI (δ −73 ppm),15 containing
four- and five-coordinated tin atoms, respectively.
(deg) in {Me2N(CH2)3}Ph(X1)SnCH2SnPh2(X2) (2−4)
2, X1 = I(1),
X2 = C(41)
3, X1 = I(1), 4, X1 = F(1),
X2 = I(2)
X2 = F(2)
Sn(1)−N(1)
2.486(4)
2.433(3)
2.400(3)
Sn(1)−X(1)
Sn(2)−X(1A)
Sn(2)−X(2)
2.9777(4)
2.9613(4)
2.1229(17)
2.2291(17)
2.0300(18)
118.32(15)
168.99(9)
176.91(8)
172.05(10)
121.87(15)
116.38(13)
121.71(15)
91.09(11)
89.43(11)
91.28(10)
114.54(13)
124.24(12)
120.55(13)
91.60(11)
94.13(10)
92.51(10)
2.161(2)
119.7(2)
164.51(8)
2.7050(5)
118.54(19)
169.76(9)
Sn(1)−C(1)−Sn(2)
N(1)−Sn(1)−X(1)
X(2)−Sn(2)−X(1A)
Sn(1)−X(1)−Sn(2A)
C(1)−Sn(1)−C(2)
C(1)−Sn(1)−C(11)
C(2)−Sn(1)−C(11)
X(1)−Sn(1)−C(1)
X(1)−Sn(1)−C(2)
X(1)−Sn(1)−C(11)
C(1)−Sn(2)−C(21)
C(1)−Sn(2)−C(31)
C(21)−Sn(2)−C(31)
X(2)−Sn(2)−C(1)
X(2)−Sn(2)−C(21)
X(2)−Sn(2)−C(31)
132.60(17)
109.20(17)
117.89(17)
88.56(13)
89.76(13)
98.26(12)
111.77(15)
110.96(16)
114.07(16)
109.13(15)
105.15(15)
105.29(16)
130.83(17)
109.69(15)
119.09(15)
90.29(11)
91.58(13)
94.64(8)
114.67(14)
113.22(13)
113.91(12)
105.47(10)
104.32(9)
103.77(9)
ESI mass spectra (positive mode) of the organotin iodides 2
and 3 showed mass clusters centered at m/z 646.1 and 696.0,
respectively, which correspond to [M − I]+.
A
119Sn NMR spectrum of a solution of compound 4 in
CDCl3 at −35 °C reveals doublet of doublet resonances at δ
3
−18 [1J(119Sn−19F) = 1168, J(119Sn−19F) = 120 Hz, SnPhF]
and δ −159 ppm [1J(119Sn−19F) = 2201, J(119Sn−19F) = 560
Hz, SnPh2F]. The chemical shift at −18 ppm is close to that
reported for the pentacoordinated tin atom Sn1 in
Ph2FSnCH2Sn1FPh-[19]-crown-6 at δ −17 ppm.16 Note-
worthy, the chemical shift of Sn2 at −159 ppm and the
coupling constants of 560 and 2201 Hz in 4 are close to the
corresponding values of δ −159 ppm [1J(119Sn−19Fa) = 2216,
the N(1) and F(1) atoms at Sn1 and F(1A) and F(2) atoms at
Sn2. The Sn(2)−F(2) distance of 2.0300(18) Å involving the
terminal fluorine atom is close to the related distances in
NEt4[CH2(SnFPh2)2·F] (2.004(2), 1.995(2) Å),6 [2-
(Me2NCH2)C6H4]Me2SnF (C, 2.0384(10) Å),11 and [2-
(Me2NCH2)C6H4]Ph2SnF (D, 2.0242(12) Å).11 The Sn(1)−
N(1) distance of 2.400(3) Å is considerably shorter than the
sum of the van der Waals radii of Sn and N (3.75 Å)12 and is
shorter than the corresponding distances in compounds C
(2.4899(14) Å)11 and D (2.5294(18) Å).11 The N(1)−Sn(1)−
F(1) angle of 168.99(9)° is rather similar to the corresponding
angles observed in compounds C and D of 167.37(5)°11 and
166.82(6)°,11 respectively. The angles F(1A)−Sn(2)−F(2) and
Sn(1)−F(1)−Sn(2A) are 176.91(8)° and 172.05(10)°, respec-
tively.
3
1J(119Sn−19Fb) = 582, J(119Sn−19Fb) = 116 Hz] reported for
Sn2 in the organofluorido stannate NBu4[(Ph2FaSn2CH2)2-
SnFbPh·Fb].17 Fa and Fb are terminal and bridging fluorine
atoms, respectively.
A
19F NMR spectrum at ambient temperature of the same
sample showed two equally intense resonances at δ −96
[1J(19F−117/119Sn) = 451, 1249 Hz, unresolved; satellite-to-
satellite-to-signal-to-satellite-to-satellite ratio approximately
6:9:70:9:6] and −188 ppm [1J(19F−117/119Sn) = 2187 Hz,
unresolved; satellite-to-signal-to-satellite ratio approximately
8:84:8]. These two chemical shifts are close to those reported
for NBu4[(Ph2Fa SnCH2)2SnFb Ph·Fb ] at δ −101
Structures of Compounds 1−4 in Solution. A 119Sn
NMR spectrum of compound 1 showed two equally intense
resonances at δ −77 ppm (SnPh3), being close to that reported
for bis(triphenylstannyl)methane, CH2(SnPh3)2, at δ −79
ppm,13 and at δ −49 ppm (Sn{(CH2)3NMe2}Ph2), respectively.
1
[1J(19F−117/119Sn) = 1174/1224, J(19F−117/119Sn) = 573 Hz]
1
and −182 ppm [1J(19F−117/119Sn) = 2163 Hz]. From a H
A
1H NMR spectrum of compound 1 showed a singlet
resonance with unresolved 117/119Sn satellites at δ 1.02 ppm
(2J(1H−117/119Sn) = 60.7 Hz) assigned to the SnCH2Sn
protons. This chemical shift is close to that reported for the
corresponding protons in CH2(SnPh3)2 at δ 0.96 ppm
(2J(1H−117/119Sn) = 63.7 Hz).13 In the 13C NMR spectrum a
chemical shift at δ −17.3 ppm (1J(13C−117/119Sn) = 252/262,
284/296 Hz) assigned to the SnCH2Sn carbon atom was
observed. This chemical shift is close to that reported for the
corresponding carbon atom in CH2(SnPh3)2 at δ −16.2 ppm
(1J(119Sn−13C) = 294 Hz).13 The chemical shift of SnCH2CH2
in 1 at δ 9.0 ppm (1J(13C−117/119Sn) = 373/391 Hz) is close to
that reported for the corresponding carbon atom in Me2N-
(CH2)3SnPh3 at δ 8.3 ppm (1J(13C−117/119Sn) = 399 Hz).8 All
these data are in agreement with the tin atoms in compound 1
being four-coordinated.
DOSY experiment a hydrodynamic radius of 5.4−5.7 Å was
calculated, which in turn indicates compound 4 being
monomeric in solution. Notably, an ESI mass spectrum
(positive mode) revealed, in addition to the major mass cluster
centered at m/z 588.1 that is assigned to [M − F]+, a rather
low-intense mass cluster centered at m/z 1191.0, which fits to
[2M − 3F + 2OH]+. At least, this supports the idea that the
formation of dimers in solution might be possible.
1
From variable-temperature H NMR spectroscopy showing
for both compounds 3 and 4 two equally intense resonances for
the NCH3 protons at T = −80 °C (3: 1.84, 2.34 ppm; 4: 1.88,
2.24 ppm) but only one resonance at room temperature (3:
2.08 ppm; 4: 1.96 ppm) it is concluded that the intramolecular
N→Sn coordination is kinetically labile on the NMR time scale
at room temperature but inert at T = −80 °C.
C
DOI: 10.1021/acs.organomet.6b00500
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
Scheme 2. Syntheses of the Trimethylene-Bridged Ditin Compounds 6 and 7
Synthesis of the Trimethylene-Bridged Ditin Com-
pounds {Me2N(CH2)3}Ph(X)Sn(CH2)3Sn(X)Ph2 (X = Ph, F).
In order to evaluate the effect of spacing between the tin
centers on the molecular structure, the trimethylene-bridged
ditin compounds {Me2N(CH2)3}Ph(X)Sn(CH2)3Sn(X)Ph2 (X
= Ph, F) were synthesized according to Scheme 2.
The reaction of 1,3-bis(triphenylstannyl)propane,
(Ph3SnCH2)2CH2 (5),18 with 0.85 molar equiv of elemental
iodine gave a crude reaction mixture, the 119Sn NMR spectrum
of which indicated this mixture to contain 29% 5 (δ −103.8
ppm), 56% Ph2ISn(CH2)3SnPh3 (5a, δ −59.6, −104.0 ppm),
and 15% (IPh2SnCH2)2CH2 (5b, δ −60.9 ppm).
As attempts failed at isolating compound 5a by both column
chromatography and crystallization, the crude reaction mixture
as mentioned above was used for subsequent reaction with an
excess of Me2N(CH2)3MgCl, providing, after purification by
column chromatography, the corresponding Me2N(CH2)3-
substituted organotin compound {Me2N(CH2)3}Ph2Sn(CH2)3-
SnPh3, 6, as a light yellowish oil in moderate yield (Scheme 2).
It shows good solubility in common organic solvents such as
CH2Cl2, CHCl3, THF, and diethyl ether. Its identity was, in
addition to elemental analyses, 1H and 13C NMR spectroscopy,
and ESI mass spectrometry (see Experimental Section),
established by 119Sn NMR spectroscopy, showing two equally
intense resonances at δ −75 (4J(119Sn−117Sn) = 48 Hz,
SnPh2(CH2)3NMe2) and δ −104 ppm (4J(119Sn−117Sn) = 48
Hz, SnPh3), respectively. These chemical shifts indicate both tin
atoms to be tetracoordinate, as the one for SnPh3 is close to the
chemical shift reported for (Ph3SnCH2)2CH2 (δ −103 ppm).18
On the other hand, replacing one phenyl group with the 3-
(dimethylamino)propyl substituent in compound 6 causes a
lower field shift of about 28 ppm.
the corresponding iodine-substituted compound {Me2N-
(CH2)3}Ph(I)Sn1(CH2)3Sn2(I)Ph2. The Sn1 atom is five-
coordinate by intramolecular N→Sn coordination, as its 119Sn
chemical shift is close to the δ −102 ppm measured for the
pentacoordinated tin atom Sn1 in compound 3. The Sn2 atom
is four-coordinate, as its 119Sn chemical shift is close to that
reported for (Ph2ISnCH2)2 (δ −54 ppm).19 The compound
{Me2N(CH2)3}Ph(I)Sn(CH2)3Sn(I)Ph2 was not isolated, but
reacted with an excess of potassium fluoride, KF, in CH2Cl2/
water, providing the triorganotin fluoride derivative {Me2N-
(CH2)3}Ph(F)Sn(CH2)3Sn(F)Ph2, 7, as a white solid material
in moderate yield (Scheme 2). It shows good solubility in
CHCl3 and CH2Cl2 and moderate solubility in ethyl acetate.
Single crystals of 7 suitable for X-ray diffraction analysis were
obtained by recrystallization from its solution in ethyl acetate at
4 °C.
Molecular Structure in the Solid State of Compound
7. The molecular structure of 7 is presented in Figure 4, and
selected interatomic distances and angles are listed in the figure
caption.
Compound 7 is a monomer in the solid state with F1→Sn2
intramolecular coordination giving a six-membered ring of half-
chair conformation (Figure 5).20
Both Sn(1) and Sn(2) tin atoms are pentacoordinated and
exhibit distorted trigonal bipyramidal geometries (geometric
goodness ΔΣ(θ) = 85.1° for Sn1 and 79.4° for Sn2) with the
equatorial positions being occupied by three carbon atoms
[C(3), C(4), C(11) at Sn(1) and C(1), C(21), and C(31) at
Sn(2)]. The axial positions are occupied by the N(1) and F(1)
atoms (at Sn(1)) and by the F(1) and F(2) atoms (at Sn(2)).
The Sn(1)−N(1) distance of 2.407(3) Å is similar to
2.400(3) Å found for the corresponding distance in the
methylene-bridged ditin compound 4. It is longer than the sum
of the covalent radii of Sn and N (2.15 Å),21 but is considerably
shorter than the sum of the van der Waals radii (3.75 Å).12 The
Sn(1)−F(1), Sn(2)−F(1), and Sn(2)−F(2) distances of
2.1266(19), 2.240(2), and 2.027(2) Å, respectively, are close
to 2.1229(17), 2.2291(17), and 2.0300(18) Å found for the
corresponding distances in 4. Also rather similar to compound
4 (see Table 1) are the interatomic angles N(1)−Sn(1)−(F1)
(169.46(11)°) and F(1)−Sn(2)−F(2) (177.27(9)°).
An ESI-MS spectrum (positive mode) of the tetraorganotin
compound 6 showed two mass clusters centered at m/z 674.1
and 752.2, which correspond to [M − Ph]+ and [M + H]+,
respectively.
The reaction of compound 6 with 2 molar equiv of elemental
iodine provided a crude reaction mixture, a 119Sn NMR
spectrum of which showed two resonances of equal integral at δ
−91 ppm (ν1/2 41 Hz) and δ −54 ppm (ν1/2 96 Hz),
respectively, that are assigned to the tin atoms Sn1 and Sn2 in
D
DOI: 10.1021/acs.organomet.6b00500
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
Complexation Behavior of 4 and 7 toward Fluoride
Anion. The reaction of compounds 4 and 7 with fluoride anion
(as NEt4F·2H2O) in CD2Cl2 solution was investigated.
A
119Sn NMR spectrum at −65 °C of a solution of
compound 4 to which had been added 1 molar equiv of NEt4F·
2H2O showed a doublet resonance at δ −60 ppm
[1J(119Sn−19F) = 1899 Hz] and a triplet resonance at δ −252
ppm [1J(119Sn−19F) = 1907 Hz], which are assigned to Sn1 and
Sn2, respectively (Scheme 3). The latter signal is close to the
triplet resonance at δ −244 ppm [1J(119Sn−19F) = 1840 Hz]
measured at −100 °C for the anion [(F2Ph2Sn)2CH2]2−.6
Scheme 3. Reaction of
{Me2N(CH2)3}Ph(F)Sn(CH2)nSn(F)Ph2 with NEt4F·2H2O
Figure 4. General view (SHELXTL) of a molecule of 7 showing 30%
probability displacement ellipsoids and the crystallographic numbering
scheme. Hydrogen atoms are omitted for clarity. Selected interatomic
distances (Å): Sn(1)−N(1) 2.407(3), Sn(1)−F(1) 2.1266(19),
Sn(2)−F(1) 2.240(2), Sn(2)−F(2) 2.027(2). Selected interatomic
angles (deg): Sn(1)−F(1)−Sn(2) 137.68(10), F(1)−Sn(1)−N(1)
169.46(11), F(1)−Sn(2)−F(2) 177.27(9), C(3)−Sn(1)−C(4)
128.24(16), C(3)−Sn(1)−C(11) 115.94(15), C(4)−Sn(1)−C(11)
115.58(15), C(3)−Sn(1)−F(1) 94.26(12), C(4)−Sn(1)−F(1)
89.91(12), C(11)−Sn(1)−F(1) 90.52(9), C(1)−Sn(2)−C(21)
127.11(14), C(1)−Sn(2)−C(31) 116.14(14), C(21)−Sn(2)−C(31)
115.81(9), C(1)−Sn(2)−F(2) 294.24(13), C(21)−Sn(2)−F(2)
91.90(10), C(31)−Sn(2)−F(2) 93.52(11).
A 19F NMR spectrum of the same sample at −60 °C showed
two resonances with a 2:1 ratio (total integral 45) at δ −140
ppm [1J(19F−117/119Sn2) = 1833/1895 Hz, F2] and δ −141 ppm
[1J(19F−117/119Sn1) = 1854 Hz, F1], respectively. These
chemical shifts are close to δ −142 ppm [1J(19F−119Sn1) =
1840 Hz] reported for [(F2Ph2Sn)2CH2]2− at −100 °C.6 In
addition to these two resonances, four broad signals were
observed at δ −93 (integral 12), δ −163 (integral 16), δ −167
(integral 19), and δ −181 ppm (integral 8). These signals were
not assigned. With caution, these signals might originate from
products formed by hydrolysis reactions. The latter are
facilitated by the presence in compound 4 of the
dimethylaminopropyl moiety acting as a base. This view gets
support from an ESI-mass spectrum (negative mode) revealing
a major mass cluster centered at m/z 719.1 that fits with [4 +
OH + MeCN + 3H2O]−.
Figure 5. Conformation of the six-membered SnC3SnF ring in
compound 7. All atoms bound to the six-membered ring are omitted
for clarity.
Structure of the Compound 7 in Solution. A 119Sn
NMR spectrum at room temperature in CDCl3 of compound 7
reveals a doublet resonance at δ −48 [1J(119Sn−19F) = 1680 Hz,
SnPhF] and a doublet of doublet resonance at δ −191 ppm
[1J(119Sn−19F) = 2030, 960 Hz, SnPh2F]. In addition to these
resonances with a total integral of 98, one signal at δ −71 ppm
(integral 2) was observed, which, however, was not assigned.
A l19Sn NMR spectrum at −80 °C of a solution of compound
7 to which had been added 1 molar equiv of NEt4F·2H2O
showed a doublet resonance at δ −47 (d, 1J(119Sn−19F) = 1566
Hz, integral 30, SnPhF, 7) and a doublet of doublet resonance
at δ −203 ppm (1J(119Sn−19F) = 2067, 941 Hz, integral 32,
SnFPh2, 7). In addition there are minor intense resonances at δ
−86 (d, 1J(119Sn−19F) = 1957 Hz, integral 12, Sn1, NEt4[7·F]),
δ −88 (d, 1J(119Sn−19F) = 1973 Hz), integral 13, not assigned),
δ −222 (3%), δ −226 (integral 4, not assigned), δ −235
(integral 2, not assigned), and δ −270 ppm (Sn2, NEt4[7·F]). A
19F NMR spectrum at −80 °C of the same sample showed two
doublet resonances at δ −143 (1J(19F−117/119Sn) = 1124, 1498/
A
19F NMR spectrum of the same sample at room
temperature showed two broad resonances of 1:1 integral
ratio at δ −145 [ν1/2 183 Hz, 1J(19F−117/119Sn) = 1688, 927 Hz,
1
F1] and δ −177 ppm [ν1/2 387 Hz, J(19F−117/119Sn) = 2097
Hz, F2], respectively, with the satellites being unresolved. These
two chemical shifts are close to δ −140 [1J(119Sn−19F) = 1250
Hz] and δ −169 ppm [1J(119Sn−19F) = 2042 Hz] reported for
6
{Ph2(Cl)Sn(CH2)3Sn(F)Ph2·F}− and to δ −139
[1J(119Sn−19Fb) = 1264 Hz] and −165 ppm [1J(119Sn−19F) =
2030 Hz] reported for{Ph2(F)Sn(CH2)3Sn(F)Ph2·F}−.6
An ESI mass spectrum (positive mode) of the organotin
fluoride 7 showed a mass cluster at m/z 632.2 that is assigned
to [M − 2F + 2OH + H]+. There is no mass cluster containing
four tin atoms, which supports that compound 7 is monomeric
in solution.
2
1564 Hz), J(19F−19F) = 83 Hz, integral 31, SnFPh, 7) and δ
−174 ppm (1J(19F−117/119Sn) = 1976/2070 Hz), 2J(19F−19F) =
83 Hz, integral 29, SnFPh2, 7). In addition there are minor
intense resonances at δ −154 (integral 14, F2, NEt4[7·F]), δ
−158 (integral 7, F1, NEt4[7·F]), δ −159 (integral 8, not
E
DOI: 10.1021/acs.organomet.6b00500
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
assigned), δ −162 (integral 2, not assigned), and δ −169 ppm
Chart 2. Methylene- and Trimethylene-Bridged Ditin
Compounds Showing Either Inter- or Intramolecular Sn−X−
Sn Bridges (X = Cl, F) in the Solid State and in Solution
(integral 9, not assigned).
A
119Sn NMR spectrum at −80 °C of a solution of
compound 7 to which had been added 2 molar equiv of NEt4F·
2H2O showed a doublet resonance at δ −86 (1J(119Sn−19F) =
1957 Hz, integral 40, Sn1, NEt4[7·F]) and a triplet at δ −271
ppm (1J(119Sn−19F) = 1888 Hz, integral 40, Sn2, NEt4[7·F]). In
addition there are minor intense resonances at δ −47 (d,
1J(119Sn−19F) = 1563 Hz, integral 5, SnPhF, 7), δ −88 (d,
1J(119Sn−19F) = 1973 Hz, integral 7, not assigned), and δ −203
ppm (dd, 1J(119Sn−19F) = 2067, 941 Hz, integral 7, SnFPh2, 7).
A
19F NMR spectrum at −80 °C of the same sample showed
two resonances with a 2:1 ratio (total integral 69) at δ −154
(integral 46, F2, NEt4[7·F]) and δ −158 ppm (integral 23, F1,
[NEt4][7·F]). In addition there are minor intense resonances at
δ −143 (d, integral 5, SnFPh, 7), δ −151 (integral 5, not
assigned), δ −156 (integral 6, not assigned), δ −160 (integral 6,
not assigned), δ −169 (integral 5, not assigned), and δ −174
ppm (d, integral 5, SnFPh2, 7). No resonances were observed in
the 119Sn NMR spectra at ambient temperature.
The 119Sn and 19F NMR data are consistent with the
equilibrium shown in Scheme 3. It is fast on the 19F and 119Sn
NMR time scales at room temperature but slow at low
temperature. For the methylene-bridged compound 4 (n = 1)
this equilibrium is on the side of the organostannate complex
NEt4[4·F] by addition of 1 molar equiv of fluoride anion only,
while 2 molar equiv of fluoride anion is needed to cause
formation of NEt4[7·F]. The results indicate the six-membered
ring involving the intramolecular Sn−F→Sn coordination in 7
to be more stable against fluoride anion attack than the four-
membered ring in 4.
but is bound to the diphenyl-substituted tin atom only. In
contrast to compound 4, the trimethylene-bridged ditin
compound 7 is monomeric both in solution and in the solid
state stabilized by intramolecular N→Sn and F→Sn coordina-
tion. The structural difference between 4 and 7 is likely the
higher ring strain in a four-membered compared to a six-
membered ring.
CONCLUSION
■
EXPERIMENTAL SECTION
■
A series of unsymmetrically substituted methylene- and
trimethylene-bridged organoditin compounds containing the
[3-(dimethylamino)propyl] moiety was synthesized and
characterized. They show N→Sn intramolecular interactions
both in solution and in the solid state. For the organotin
fluorides 4 and 7, this interaction results in a much better
solubility in common organic solvents with respect to the
corresponding compounds Ph2FSn(CH2)nSnPh2F (n = 1, 3),
lacking an intramolecularly coordinating substituent. Notably,
the latter compounds do not get solubilized by addition of
triethyl amine, NEt3, or even HMPA, (Me2N)3PO.6 Compound
4 is monomeric in solution and shows an intramolecular F→Sn
coordination that is kinetically inert at low temperature on the
19F and 119Sn NMR time scales (see 4a in Chart 2). Upon
crystallization, it dimerizes as a result of intermolecular F→Sn
coordination (see 4b in Chart 2). The organostannate anion E,
however, in which the intramolecularly coordinating dimethy-
laminopropyl moiety in 4 is formally replaced by a phenyl
substituent and a fluoride anion, does not dimerize in the solid
state and shows an intramolecular Sn−F−Sn bridge.6a
In the chlorine-substituted compound F even the neutral
Lewis base (Me2N)3PO causes an intramolecular Sn−Cl−Sn
bridge, but no dimerization.6b
Upon addition to compound 4 of fluoride anion, as NEt4F·
2H2O, in CD2Cl2 solution, the salt NEt4[4·F] containing an
organostannate anion is formed. The same holds for compound
7, giving the salt NEt4[7·F]. On the basis of NMR data, the
intramolecular N→Sn coordination is retained and the
incoming fluoride anion does not bridge the two tin centers
General Considerations. All solvents were dried and purified
according to standard procedures and freshly distilled prior to use.
Me2N(CH2)3Cl,8 {Me2N(CH2)3}(Ph2)SnI,8 Ph3SnCH2Br,9
(Ph3Sn)2CH2,13 and (Ph3SnCH2)2CH2 were synthesized according
18
to literature methods. {Me2N(CH2)3Cl}·HCl and tetraethylammo-
nium fluoride were commercially available, and they were used without
further purification. Bruker DPX-300, DRX-400, and AVIII-500
spectrometers were used to obtain 1H, 13C, 19F, and 119Sn NMR
1
spectra. Solution H, 13C, 19F, and 119Sn NMR chemical shifts are
given in ppm and were referenced to Me4Si (1H, 13C), CFCl3 (19F),
and Me4Sn (119Sn). Elemental analyses were performed on a LECO-
CHNS-932 analyzer. The electrospray mass spectra were recorded
with a Thermoquest−Finnigan instrument, using CH3CN, MeOH, or
CH2Cl2 as the mobile phase.
The DOSY (diffusion-ordered spectroscopy) measurement was
performed with a pulse sequence using double stimulated echo for
convection compensation and LED and bipolar gradient pulses for
diffusion (A. Jerschow and N. Mueller, J. Magn. Reson. A 1996, 123,
222−225; A. Jerschow and N. Mueller, J. Magn. Reson. A 1997, 125,
372−375). The measurements were executed with an AVANCE-III
HD 600 MHz NMR spectrometer equipped with a 5 mm helium-
cooled BBFO probe from Bruker BioSpin GmbH (Rheinstetten,
Germany). Thirty-two different gradient strengths varying between 3%
and 95% of the maximum strength of 53 G/cm were used. Thirty-two
scans per gradient strength were acquired with 16 kB data points of the
FID (acquisition time of 0.97 s) and a relaxation delay of 1.5 s.
According to the DOSY figure, the expansion indicates two
components with diffusion coefficients of 7.09 × 10−10 and 7.45 ×
10−10 m2/s. With the Stokes−Einstein equation, a hydrodynamic
radius of about 0.57−0.54 nm can be calculated.
Crystallography. Intensity data for all crystals were collected on
an XcaliburS CCD diffractometer (Oxford Diffraction) using Mo Kα
F
DOI: 10.1021/acs.organomet.6b00500
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
radiation at 110 K. The structures were solved with direct methods
using SHELXS-97, and refinements were carried out against F2 by
using SHELXL-2014.22 The C−H hydrogen atoms were positioned
with idealized geometry and refined using a riding model. All non-
hydrogen atoms were refined using anisotropic displacement
parameters. Parts of compound 2 are affected by substitutional
disorder: the same site is occupied by the phenyl group C(41)−C(46)
in 90% of unit cells and by iodide I(2) in 10% of unit cells. This
disorder was refined by a split model over two positions; their
occupancies were allowed to refine freely to yield 0.89527:0.10473 and
then restrained to integer values 0.9:0.1.
CCDC-1484757 (2), CCDC-1484758 (3), CCDC-1484759 (4),
and CCDC-1484760 (7) contain the supplementary crystallographic
data for this paper. These data can be obtained free of charge from the
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
Synthesis of {Me2N(CH2)3}Ph2SnCH2SnPh3 (1). A solution of
Ph3SnCH2MgBr, prepared from Ph3SnCH2Br (2.000 g, 4.51 mmol)
and magnesium (0.110 g, 4.51 mmol) in THF (50 mL), was added
dropwise to a stirred solution of Me2N(CH2)3Ph2SnI (1.970 g, 4.05
mmol) in THF (60 mL) for a period of 1 h. After the addition had
been completed, the reaction mixture was heated at reflux overnight
and then cooled to room temperature. THF was distilled off under
reduced pressure; then cold water (60 mL) was added, and the
mixture was extracted three times with 50 mL of dichloromethane.
The combined organic phases were dried with MgSO4 and the
solvents evaporated under vacuum to give the crude product. It was
purified by column chromatography (SiO2, n-hexane/ethyl acetate,
5:1, ethanol) to give 1.240 g (38%) of 1 as a yellow oil.
Synthesis of [{Me2N(CH2)3}PhISnCH2SnIPh2] (3). Iodine (0.912
g, 3.60 mmol) was added in small portions and under ice cooling to a
stirred solution of 1 (1.300 g, 1.80 mmol) in CH2Cl2 (70 mL). Stirring
was continued while warming to room temperature overnight. The
solvent and the iodobenzene were removed in vacuo to afford 1.410 g
(95%) of 3 as a slightly yellow solid (mp 163−165). Single crystals of
3 suitable for X-ray diffraction analysis were obtained by slow
evaporation of a solution of the compound in CH2Cl2/n-hexane.
1H NMR (400.13 MHz, CDCl3): δ 1.30−1.73 (m, 4H, SnCH2Sn +
SnCH2), 2.09 (8H, N(CH3)2 + SnCH2CH2), 2.36 (t, 2H, CH2N),
7.36−7.99 (15H, Ph). 13C{1H} NMR (100.63 MHz, CDCl3): δ 7.1
(SnCH2Sn), 18.7 (SnCH2), 21.7 (2J(13C−117/119Sn) = 33 Hz,
SnCH2 CH2 ), 46.3 (N(CH3)2 ), 61.1 (CH2 −N), 128.5
(3J(13C−117/119Sn) = 65 Hz, SnIPh2, Cm), 128.6 (3J(13C−117/119Sn) =
60 Hz, SnIPh, Cm), 129.3 (SnIPh, Cp), 129.8 (4J(13C−117/119Sn) = 14
Hz, SnIPh2, Cp), 134.3 (SnIPh, Co), 136.6 (2J(13C−117/119Sn) = 51 Hz,
SnIPh2, Co), 137.2 (SnIPh, Ci), 138.2 (SnIPh2, Ci). 119Sn{1H} NMR
(111.92 MHz, CDCl3): δ −54 (SnIPh2), −102 (SnIPh). Anal. Calcd
(%) for C24H29I2NSn2 (822.72): C 35.04, H 3.55, N 1.70. Found: C
35.2, H 3.6, N 1.5. Electrospray MS: m/z (%) positive mode, 696.0
−
(20, [M − I]+); negative mode, 380.7 (100, I3 ), 126.9 (64, I−).
Synthesis of [{Me2N(CH2)3}PhFSnCH2SnFPh2] (4). A solution of
3 (1.000 g, 1.22 mmol) in CH2Cl2 (30 mL) was mixed with a solution
of KF (71 mg, 12.15 mmol) in water (30 mL). The biphasic mixture
was stirred at room temperature for 8 days. The organic phase was
then separated and dried over MgSO4. Removing the solvent in vacuo
afforded a yellow solid. This solid was dissolved in acetone, and the
solution was cooled at −5 °C for several days to give 400 mg (53%) of
pure 4 as a white solid (mp 168−170 °C). Single crystals of 4 suitable
for X-ray diffraction analysis were obtained by slow evaporation of a
solution of the compound in acetone at −5 °C.
1H NMR (400.13 MHz, CDCl3): δ 1.02 (s, 2J(1H−117/119Sn) = 60.7
Hz, 2H, SnCH2Sn), 1.24 (t, 2H, Sn−CH2), 1.84 (m, 2H, SnCH2CH2),
2.26 (s, 6H, N(CH3)2), 2.30 (t, 2H, CH2N), 7.39−7.69 (25H, Ph).
13C{1H} NMR (100.63 MHz, CDCl3): δ −17.3 (1J(13C−117/119Sn) =
252/262, 284/296 Hz, SnCH2Sn), 9.0 (1J(13C−117/119Sn) = 373/391
Hz, SnCH2), 24.1 (2J(13C−117/119Sn) = 19 Hz, SnCH2CH2), 45.2
N(CH3)2, 63.0 (3J(13C−117/119Sn) = 70 Hz, CH2N), 128.1
(3J(13C−117/119Sn) = 47 Hz, SnPh2, Cm), 128.2 (3J(13C−117/119Sn) =
50 Hz, SnPh3, Cm), 128.4 (SnPh2, Cp), 128.7 (4J(13C−117/119Sn) = 12
Hz, SnPh3, Cp), 136.4 (2J(13C−117/119Sn) = 36 Hz, SnPh2, Co), 136.7
(2J(13C−117/119Sn) = 38 Hz, SnPh3, Co), 139.3 (1J(13C−117/119Sn) =
488/510 Hz, 3J(13C−117/119Sn) = 9 Hz, SnPh3, Ci), 140.4
(1J(13C−117/119Sn) = 448/468 Hz,3J(13C−117/119Sn) = 13 Hz, SnPh2,
1H NMR (499.79 MHz, CDCl3): δ 0.86−2.23 (complex pattern,
14H), 6.80−7.86 (15H, Ph). 13C{1H} NMR (125.68 MHz, CDCl3): δ
2.9 (SnCH2Sn), 9.9 (SnCH2), 21.5 (SnCH2CH2), 46.2 (N(CH3)2),
61.7 (CH2N), 128.0 (3J(13C−117/119Sn) = 66 Hz, SnFPh2, Cm), 128.7
(SnFPh, Cm), 128.9 (SnFPh2, Cp), 129.7 (SnFPh, Cp), 135.1 (SnFPh,
Co), 136.2 (SnFPh2, Co), 140.2 (SnFPh, Ci), 142.7 (SnFPh2, Ci).
19F{1H} NMR (282.36 MHz, CDCl3): δ −95 (1J(19F−119Sn) = 1120
Hz, SnFPh), −185 (1J(19F−119Sn) = 2221 Hz, SnFPh2). 119Sn{1H}
1
NMR (111.92 MHz, CDCl3, −35 °C): δ −18 (dd, J(119Sn−19F) =
1168 Hz, 3J(119Sn−19F) = 120 Hz, SnFPh), −159 (dd, 1J(119Sn−19F) =
2201 Hz, 560 Hz SnFPh2). Anal. Calcd (%) for C24H29F2NSn2
(606.91): C 47.50, H 4.82, N 2.31. Found: C 47.2, H 5.0, N 2.0.
Electrospray MS: m/z (%) positive mode, 588.1 (100, [M − F]+),
1191.0 (4, [2M − 3F + 2OH]+), negative mode 624.1 (2, [M +
OH]−).
Ci). 119Sn{1H} NMR (111.92 MHz, CDCl3):
δ −49
(2J(119Sn−117/119Sn) = 236 Hz, SnPh2), −77 (2J(119Sn−117/119Sn) =
232 Hz, SnPh3). Anal. Calcd (%) for C36H39NSn2 (723.09): C 59.79,
H 5.44, N 1.94. Found: C 60.0, H 5.6, N 1.6.
Reaction of {Me2N(CH2)3}Ph(F)SnCH2Sn(F)Ph2 (4) with NEt4F·
2H2O. Compound 4 (0.070 g, 0.12 mmol) and tetraethylammonium-
fluoride dihydrate (0.021 g, 0.12 mmol) were mixed in CD2Cl2 and
stirred for 5 min. From the resulting solution, NMR spectra were
recorded.
Synthesis of {Me2N(CH2)3}PhISnCH2SnPh3 (2). Elemental
iodine (0.035 g, 0.41 mmol) was added in small portions and under
ice cooling to a stirred solution of 1 (0.100 g, 0.41 mmol) in CH2Cl2
(20 mL). Stirring was continued while warming to room temperature
overnight. The solvent and the iodobenzene were removed in vacuo to
afford 0.086 g (80%) of 2 as a slightly yellow solid. Single crystals of 2
suitable for X-ray diffraction analysis were obtained by slow
evaporation of a solution of the compound in CH2Cl2/n-hexane.
1H NMR (499.79 MHz, CDCl3): δ 0.59 (s, 2H, SnCH2Sn), 1.27−
1.65 (complex pattern, 4H, SnCH2 + SnCH2CH2), 1.92 (s, 6H,
N(CH3)2), 2.16 (t, 2H, CH2N), 7.34−7.88 (20H, Ph). 13C{1H} NMR
(125.68 MHz, CDCl3): δ −5.2 (1J(13C−117/119Sn) = 281/295 Hz,
SnCH2Sn), 19.1 (SnCH2), 21.9 (2J(13C−117/119Sn) = 35 Hz,
SnCH2CH2), 46.3 (N(CH3)2), 61.1 (3J(13C−117/119Sn) = 61 Hz,
CH2N), 128.4 (3J(13C−117/119Sn) = 51 Hz, SnIPh + SnPh3, Cm), 128.8
(SnIPh, Cp), 128.9 (4J (13C−117/119Sn) = 11 Hz, SnPh3, Cp),
19F{1H} NMR (282.36 MHz, CD2Cl2, −60 °C): δ −93(12%), −140
1
(30%, J(19F−117/119Sn) = 1833/1895 Hz, 2F, SnF2Ph), −141 (15%,
1J(19F−117/119Sn) = 1854 Hz, SnFPh), −163(16%), −167(19%),
−181(8%). 119Sn{1H} NMR (111.89 MHz, CD2Cl2, −65 °C): δ −60
1
1
(d, J(119Sn−19F) = 1899 Hz, SnFPh), −252 (t, J(119Sn−19F) = 1907
Hz, SnF2Ph). Electrospray MS: m/z (%) positive mode, 130.2 (100,
NEt4 ); negative mode, 719.1 (100, M − Et4N − F + OH + 3H2O +
MeCN).
+
Synthesis of {Me2N(CH2)3}Ph2Sn(CH2)3SnPh3 (6). Elemental
iodine (2.910 g, 11.45 mmol) was added in small portions under ice-
cooling to a stirred solution of Ph3Sn(CH2)3SnPh3 (10.000 g, 13.47
mmol) in CH2Cl2 (200 mL). The reaction mixture was stirred
overnight. The solvent and the iodobenzene were removed in vacuo.
The residue thus obtained contained a mixture, hereafter referred to as
mixture A, consisting of three compounds. 119Sn{1H} NMR (111.92
MHz, CDCl3): δ −59.6 (Ph3Sn(CH2)3SnPh2I, 28%), −60.9
((IPh2SnCH2)2CH2, 15%), −103.8 ((Ph3SnCH2)2CH2, 29%),
−104.0 (Ph3Sn(CH2)3SnPh2I, 28%). To a solution of the mixture A
in THF (150 mL) was added the Grignard reagent prepared from
134.1(2J(13C−117/1 19Sn)
= 45 Hz, SnIPh, Co), 137.1
(2J(13C−117/119Sn) = 38 Hz, SnPh3, Co), 139.1 (1J(13C−117/119Sn) =
497/520, SnPh3, Ci), 144.5 (SnIPh, Ci). 119Sn{1H} NMR (111.92
MHz, CDCl3): δ −54 (5%), −86 (SnPh3), −92 (SnIPh), −102 (5%).
Electrospray MS: m/z (%) positive mode, 646.1 (100, [M − I]+),
614.1 (40, [M − I − 2Ph + 2OH + MeOH + 3H2O]+), (1, [M + H]+);
−
negative mode, 127.0 (100, I−), 380.8 (17, I3 ).
G
DOI: 10.1021/acs.organomet.6b00500
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
1
Me2N(CH2)3Cl (1.390 g, 11.43 mmol) and magnesium turnings
(0.300 g, 12.3 mmol) in THF (40 mL). After the completion of the
addition, the mixture was stirred overnight at room temperature. The
mixture was then heated at reflux for 3 h before it was cooled to room
temperature. THF was distilled off under reduced pressure; then cold
water (100 mL) was added, and the mixture was extracted with
dichloromethane. The combined organic phases were dried with
MgSO4 and the solvents evaporated in vacuo to give the crude
product. The latter was purified by column chromatography on silica
gel using CH2Cl2 to separate the unreacted Ph3Sn(CH2)3SnPh3
compound, then using acetone to separate the target compound 6.
The latter was obtained as a yellow oil (2.410 g, 24% overall yield).
1H NMR (400.13 MHz, CDCl3): δ 1.20 (t, 2H, SnCH2), 1.51 (t,
2H, CH2SnCH2(CH2)2Sn), 1.66 (t, 2H, Sn(CH2)2CH2Sn), 2−2.15
(m, 4H, 2H SnCH2CH2 + 2H SnCH2CH2CH2Sn), 2.59 (s, 6H,
N(CH3)2), 2.95 (t, 2H, CH2N), 7.34−7.63 (25H, Ph). 13C{1H} NMR
(100.63 MHz, CDCl3): δ 6.2 (1J(13C−117/119Sn) = 319/333 Hz, Sn−
CH2(L)), 15.5 (1J(13C−117/119Sn) = 352/368 Hz, SnCH2), 15.9
(1J(13C−117/119Sn) = 382 Hz, SnCH2), 21.1 (2J(13C−117/119Sn) = 15
Hz, SnCH2CH2CH2Sn), 24.1 (2J(13C−117/119Sn) = 20 Hz,
SnCH2CH2), 42.5 N(CH3)2, 60.3 (3J(13C−117/119Sn) = 67 Hz,
CH2N), 128.2 (SnPh3, Cm), 128.4 (SnPh2, Cm), 128.6 (SnPh3, Cp),
128.7 (SnPh2, Cp), 136.5 (2J(13C−117/119Sn) = 35 Hz, SnPh2, Co),
136.7 (2J(13C−117/119Sn) = 35 Hz, SnPh3, Co) 138.1 (SnPh2, Ci), 138.5
(SnPh3, Ci). 119Sn{1H} NMR (111.92 MHz, CDCl3): δ −76 (SnPh2),
−104 (SnPh3). Anal. Calcd (%) for C38H43NSn2 (751.19): C 60.76, H
5.77, N 1.86. Found: C 60.0, H 5.9, N 1.8. Electrospray MS: m/z (%)
positive mode, 674.1 (58, [M − Ph]+), 752.2 (2, [M + H]+).
1J(119Sn−19F) = 1566 Hz, SnFPh, 7), −86 (12%, d, J(119Sn−19F) =
1957 Hz, SnFPh, [NEt4][7·F]), −88 (13%, d, J(119Sn−19F) = 1973
1
Hz), −203 (32%, dd, 1J(119Sn−19F) = 2067, 941 Hz, SnFPh2, 7), −222
(3%), −226 (4%), −235 (2%), −270 (SnF2Ph2, [NEt4][7·F]).
Reaction of {Me2N(CH2)3}Ph(F)Sn(CH2)3Sn(F)Ph2 (7) with 2
molar equiv of NEt4F·2H2O. Compound 7 (0.035 g, 0.06 mmol)
and tetraethylammonium fluoride dihydrate (0.020 g, 0.11 mmol)
were mixed in CD2Cl2 and stirred for 5 min.
19F{1H} NMR (376.6 MHz, CD2Cl2, −80 °C): δ −143 (5%, d,
SnFPh, 7), −151 (5%), −154 (46%, SnF2Ph2, [NEt4][7·F]), −156
(6%), −158 (23%, SnFPh, [NEt4][7·F]), −160 (6%), −169 (5%),
−174 (5%, d, SnFPh2, 7). 119Sn{1H} NMR (149.26 MHz, CD2Cl2,
−80 °C): δ −47 (5%, d, J(119Sn−19F) = 1563 Hz, SnFPh, 7), −86
1
(40%, d, 1J(119Sn−19F) = 1957 Hz, SnFPh, [NEt4][7·F]), −88 (8%, d,
1J(119Sn−19F) = 1973 Hz), −203 (7%, dd, J(119Sn−19F) = 2067, 941
1
Hz, SnFPh2, 7), −271 (40%, t, J(119Sn−19F) = 1888 Hz, SnF2Ph2,
1
[NEt4][7·F]).
ASSOCIATED CONTENT
* Supporting Information
■
S
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.organo-
met.6b00500.
NMR spectra, ESI mass spectra, and crystallographic data
(PDF)
Crystallographic data for 2−4 and 7 (CIF)
Synthesis of {Me2N(CH2)3}PhFSn(CH2)3SnFPh2 (7). Elemental
iodine (0.300 g, 1.20 mmol) was added in small portions and under ice
cooling to a stirred solution of 6 (0.450 g, 0.60 mmol) in CH2Cl2 (30
mL). Stirring was continued while warming to room temperature
overnight. The solvent and iodobenzene were removed in vacuo to
afford {Me2N(CH2)3}Ph(I)Sn(CH2)3Sn(I)Ph2 as a yellow oil, which
was used for the next reaction without further purification. 119Sn{1H}
NMR (CDCl3, 149.26 MHz): δ −54 (SnIPh2), −91 ({Me2N(CH2)3}
SnIPh). A solution of {Me2N(CH2)3}Ph(I)Sn(CH2)3Sn(I)Ph2 (0.300
g, 0.35 mmol) in CH2Cl2 (10 mL) was mixed with a solution of KF
(0.200 g, 3.53 mmol) in water (15 mL). The biphasic mixture was
stirred at room temperature for 3 days. The organic phase was then
separated and dried over MgSO4. Removing the solvent in vacuo
afforded a white solid. This solid was dissolved in ethyl acetate, and the
solution was cooled at −5 °C for several days to give 0.100 g (45%) of
7 as a white solid (mp 142−144 °C). Single crystals of 7 suitable for X-
ray diffraction analysis were obtained by slow evaporation of a solution
of the compound in ethyl acetate at 4 °C.
AUTHOR INFORMATION
Corresponding Author
*E-mail: klaus.jurkschat@tu-dortmund.de.
Notes
■
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
N.A. is grateful to Damascus University for a scholarship.
■
REFERENCES
■
(1) Selected reviews: (a) Gale, P. A. Coord. Chem. Rev. 2003, 240,
191−221. (b) Gale, P. A.; Quesada, R. Coord. Chem. Rev. 2006, 250,
3219−3244. (c) Lee, C.-H.; Miyaji, H.; Yoon, D.-W.; Sessler, J. L.
Chem. Commun. 2008, 24−34. (d) Vilar, R. Eur. J. Inorg. Chem. 2008,
2008, 357−367. (e) Caltagirone, C.; Gale, P. A. Chem. Soc. Rev. 2009,
38, 520−563. (f) Hudnall, T. W.; Chiu, C.-W.; Gabbaï, F. P. Acc.
Chem. Res. 2009, 42, 388−397. (g) Cametti, M.; Rissanen, K. Chem.
Commun. 2009, 2809−2829. (h) Wade, C. R.; Broomsgrove, A. E. J.;
Aldridge, S.; Gabbaï, F. P. Chem. Rev. 2010, 110, 3958−3984. (i) Gale,
P. A. Chem. Commun. 2011, 47, 82−86. (j) Zhou, Y.; Zhang, J. F.;
Yoon, J. Chem. Rev. 2014, 114, 5511−5571. (k) Dutta, R.; Ghosh, P.
Chem. Commun. 2015, 51, 9070−9084. (l) Langton, M. J.; Serpell, C.
J.; Beer, P. D. Angew. Chem., Int. Ed. 2016, 55, 1974−1987.
1H NMR (300.13 MHz, CDCl3): δ 12.7 (complex pattern, 18H),
6.90−7.86 (15H, Ph). 13C{1H} NMR (75.48 MHz, CDCl3): δ 10.2
(Sn−CH2), 10.5 (SnCH2), 18.5 (SnCH2), 21.4 (2J(13C−117/119Sn) =
29 Hz, SnCH2CH2), 22.1 (SnCH2CH2CH2−Sn), 45.8 N(CH3)2, 61.6
(CH2N), 127.6 (SnFPh2, Cm), 128.3 (SnFPh, Cm), 128.7 (SnFPh2,
Cp), 129.5 (SnFPh, Cp), 135.2 (SnFPh, Co), 136.3 (SnFPh2, Co) 136.9
(SnFPh, Ci), 137.3 (SnFPh2, Ci). 19F{1H} NMR (376.61 MHz,
1
CDCl3): δ −146 (ν1/2 183 Hz, J(19F−117/119Sn) = 1688, 927 Hz,
1
SnFPh), −177 (ν1/2 387 Hz, J(19F−117/119Sn) = 2097 Hz, SnFPh2).
(2) (a) Wuest, J. D. Acc. Chem. Res. 1999, 32, 81−89.
(b) Hoefelmeyer, J. D.; Schulte, M.; Tschinkl, M.; Gabbaï, F. P.
Coord. Chem. Rev. 2002, 235, 93−103. (c) Venkatasubbaiah, K.; Bats, J.
1
119Sn{1H} NMR (149.26 MHz, CDCl3): δ −47 (d, J(119Sn−19F) =
1698 Hz, SnFPh), −190 (dd, 1J(119Sn−19F) = 2062, 950 Hz, SnFPh2).
Anal. Calcd (%) for C26H33F2NSn2·CH2Cl2 (719.90): C 45.05, H 4.90,
N 1.95. Found: C 45.5, H 5.2, N 2.0. Electrospray MS: m/z (%)
positive mode, 632.2 (5, [M − 2F + 2OH + H]+).
W.; Arnold, L.; Rheingold, A. L.; Jakle, F. Organometallics 2005, 24,
̈
6043−6050. (d) Boshra, R.; Venkatasubbaiah, K.; Doshi, A.;
Lalancette, R. A.; Kakalis, L.; Jakle, F. Inorg. Chem. 2007, 46,
̈
Reaction of {Me2N(CH2)3}Ph(F)Sn(CH2)3Sn(F)Ph2 (7) with 1
molar equiv of NEt4F·2H2O. Compound 7 (0.040 g, 0.06 mmol)
and tetraethylammonium fluoride dihydrate (0.012 g, 0.06 mmol)
were mixed in CD2Cl2 and stirred for 5 min.
10174−10186. (e) Galbraith, E.; Fyles, T. M.; Marken, F.; Davidson,
M. G.; James, T. D. Inorg. Chem. 2008, 47, 6236−6244. (f) Kim, Y.;
Gabbaï, F. P. J. Am. Chem. Soc. 2009, 131, 3363−3369. (g) Zhao, H.;
Gabbaï, F. P. Nat. Chem. 2010, 2, 984−990. (h) Zhao, H.; Gabbaï, F.
P. Org. Lett. 2011, 13, 1444−1446. (i) Villamil-Ramos, R.; Yatsimirsky,
A. K. Appl. Organomet. Chem. 2011, 25, 356−365. (j) Weisheim, E.;
19F{1H} NMR (376.6 MHz, CD2Cl2, −80 °C): δ −143 (31%, d,
1J(19F−117/119Sn) = 1124, 1498/1564 Hz), 2J(19F−19F) = 83 Hz,
SnFPh, 7), −154 (14%, SnF2Ph2, [NEt4][7·F]), −158 (7%, SnFPh,
[NEt4][7·F]), −159 (8%), − 162 (2%), −169 (9%), −174 (29%, d,
1J(19F−117/119Sn) = 1976/2070 Hz), 2J(19F−19F) = 83 Hz, SnFPh2, 7).
119Sn{1H} NMR (149.26 MHz, CD2Cl2, −80 °C): δ −47 (30%, d,
Bucker, L.; Neumann, B.; Stammler, H.-G.; Mitzel, N. W. Dalton
̈
Trans. 2016, 45, 198−207. (k) Reddy, T. S.; Maragani, R.; Misra, R.
Dalton Trans. 2016, 45, 2549−2553. (l) Tugashov, K. I.; Gribanyov, D.
A.; Dolgushin, F. M.; Smol’yakov, A. F.; Peregudov, A. S.; Minacheva,
H
DOI: 10.1021/acs.organomet.6b00500
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
M. K.; Irina, A.; Tikhonova, I. A.; Shur, V. B. Organometallics 2016, 35,
2197−2206. (m) Hirai, M.; Myahkostupov, M.; Castellano, F. N.;
Gabbaï, F. P. Organometallics 2016, 35, 1854−1860. (n) Wendji, A. S.;
Dietz, C.; Kuhn, S.; Lutter, M.; Schollmeyer, D.; Hiller, W.; Jurkschat,
̈
K. Chem. - Eur. J. 2016, 22, 404−416. (o) Perdikaki, K.; Tsagkatakis, I.;
Chaniotakis, N. A.; Altmann, R.; Jurkschat, K.; Reeske, G. Anal. Chim.
Acta 2002, 467, 197−204.
(3) Chaniotakis, N.; Jurkschat, K.; Muller, D.; Perdikaki, K.; Reeske,
̈
G. Eur. J. Inorg. Chem. 2004, 2004, 2283−2288.
(4) Tsagkatakis, I.; Chaniotakis, N.; Altmann, R.; Jurkschat, K.;
Willem, R.; Martins, J. C.; Qin, Y.; Bakker, E. Helv. Chim. Acta 2001,
84, 1952−1961.
(5) Chaniotakis, N. A.; Jurkschat, K.; Reeske, G.; Volosirakis, A. Anal.
Chim. Acta 2005, 553, 185−189.
(6) (a) Dakternieks, D.; Jurkschat, K.; Zhu, H.; Tiekink, E. R. T.
Organometallics 1995, 14, 2512−2521. (b) Gielen, M.; Jurkschat, K.;
Meunier-Piret, J.; van Meerssche, M. Bull. Soc. Chim. Belg. 1984, 93,
379−391.
(7) Pieper, N.; Klaus-Mrestani, C.; Schurmann, M.; Jurkschat, K.;
̈
Biesemans, M.; Verbruggen, I.; Martins, J. C.; Willem, R. Organo-
metallics 1997, 16, 1043−1052.
(8) Zickgraf, A.; Beuter, M.; Kolb, U.; Drager, M.; Tozer, R.;
̈
Dakternieks, D.; Jurkschat, K. Inorg. Chim. Acta 1998, 275−276, 203−
214.
(9) Seyferth, D.; Brian Andrews, S. J. Organomet. Chem. 1971, 30,
151−166.
(10) Han, X.; Hartmann, G. A.; Brazzale, A.; Gaston, R. D.
Tetrahedron Lett. 2001, 42, 5837−5839.
(11) Bares,
Císarova, I.; Ruzick
2971.
̌
J.; Novak
́
, P.; Nad
́ ́
vorník, M.; Jambor, R.; Lebl, T.;
̌
́
̌
̌
a, A.; Holece
̌
k, J. Organometallics 2004, 23, 2967−
̊
(12) Batsanov, S. S. Inorg. Mater. 2001, 37, 871−885.
(13) Gielen, M.; Jurkschat, K. J. Organomet. Chem. 1984, 273, 303−
312.
(14) Cox, P. J.; Garden, S. J.; Howie, R.; Melvin, O. A.; Wardell, J. L.
J. Organomet. Chem. 1996, 516, 213−224.
(15) Varga, R. A.; Rotar, A.; Schurmann, M.; Jurkschat, K.; Silvestru,
̈
C. Eur. J. Inorg. Chem. 2006, 2006, 1475−1486.
(16) Tagne Kuate, A. C. Ph.D. thesis, TU Dortmund, 2009.
(17) Altmann, R.; Jurkschat, K.; Schurmann, M.; Dakternieks, D.;
̈
Duthie, A. Organometallics 1997, 16, 5716−5723.
(18) Dakternieks, D.; Jurkschat, K.; Schollmeyer, D.; Wu, H. J.
Organomet. Chem. 1995, 492, 145−150.
(19) Jurkschat, K.; Hesselbarth, F.; Dargatz, M.; Lehmann, J.;
Kleinpeter, E.; Tzschach, A.; Meunier-Piret, J. J. Organomet. Chem.
1990, 388, 259−271.
(20) Nelson, D. J.; Brammer, C. N. J. Chem. Educ. 2011, 88, 292−
294.
(21) Cordero, B.; Gomez, V.; Platero-Prats, A. E.; Reves, M.;
Echeverria, J.; Cremades, E.; Barragan, F.; Alvarez, S. Dalton Trans.
2008, 2832−2838.
(22) (a) Sheldrick, G. M. Acta Crystallogr., Sect. A: Found. Crystallogr.
2008, A64, 112−122. (b) Sheldrick, G. M. Acta Crystallogr. 2015, C71,
3−8.
I
DOI: 10.1021/acs.organomet.6b00500
Organometallics XXXX, XXX, XXX−XXX