Tri- and diorganostannates containing 2-(N,N-dimethylaminomethyl)phenyl ligand

Article abstract of DOI:10.1016/j.jorganchem.2010.08.006

The C,N-chelated tri and diorganotin(IV) chlorides react with both protic mineral acids and carboxylic acids. The nitrogen atom of the L^CN ligand (where L^CN is 2-(dimethylaminomethyl)phenyl) is thus quarternized - protonated and new Sn-X bond (X = Cl, Br, I or the remainder of the starting acid used) is simultaneously formed. The set of zwitterionic tri and diorganostannates containing protonated 2-(dimethylaminomethyl)phenyl-moiety was prepared and structurally characterized by multinuclear NMR spectroscopy and XRD techniques. In all these cases, the intramolecular N-H?X bond is present in the molecule. Despite the central tin atom remains five-coordinated (except for the [HL^CNH]⁺[(n-Bu)₂SnCl(NO ₃)₂]^-) and reveals a distorted trigonal bipyramidal geometry, the ¹¹⁹Sn NMR chemical shift values of these zwitterionic stannates are somewhat shifted to the higher field than corresponding starting C,N-chelated tri and diorganotin(IV) halides. Reactions of C,N-chelated organotin(IV) halides with various Lewis acids are also discussed.

Full text of DOI:10.1016/j.jorganchem.2010.08.006

Journal of Organometallic Chemistry 695 (2010) 2475e2485
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Tri- and diorganostannates containing
2-(N,N-dimethylaminomethyl)phenyl ligand
a
b
a
a,
a
ꢀ
ꢀ
*
ꢀ
ꢀ
ꢀ
ꢀ ꢁꢀ ꢀ
ꢀ
Petr Svec , Eva Cernosková , Zdenka Padelková , Ales Ruzicka , Jaroslav Holecek
a Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, CZ-532 10 Pardubice, Czech Republic
b Joint Laboratory of Solid State Chemistry IMC CAS, University of Pardubice, Studentská 84, CZ-532 10 Pardubice, Czech Republic
a r t i c l e i n f o
a b s t r a c t
Article history:
The C,N-chelated tri and diorganotin(IV) chlorides react with both protic mineral acids and carboxylic acids.
The nitrogen atom of the LCN ligand (where LCN is 2-(dimethylaminomethyl)phenyl) is thus quarternized e
protonated and new SneX bond (X ¼ Cl, Br, I or the remainder of the starting acid used) is simultaneously
formed. The set of zwitterionic tri and diorganostannates containing protonated 2-(dimethylaminomethyl)
phenyl-moiety was prepared and structurally characterized by multinuclear NMR spectroscopy and XRD
techniques. In all these cases, the intramolecular NeH/X bond is present in the molecule. Despite the
central tin atom remains five-coordinated (except for the [HLCNH]þ[(n-Bu)2SnCl(NO3)2]ꢀ) and reveals
a distorted trigonal bipyramidal geometry, the 119Sn NMR chemical shift values of these zwitterionic
stannates are somewhat shifted to the higher field than corresponding starting C,N-chelated tri and dio-
rganotin(IV) halides. Reactions of C,N-chelated organotin(IV) halides with various Lewis acids are also
discussed.
Received 8 July 2010
Received in revised form
3 August 2010
Accepted 4 August 2010
Available online 12 August 2010
Keywords:
Organotin(IV) compounds
Stannates
Zwitterion
C,N-Ligand
Crystal structure
NMR spectroscopy
Ó 2010 Elsevier B.V. All rights reserved.
1. Introduction
compounds (LNCN is 2,6-bis(dimethylaminomethyl)phenyl), the
zwitterionic species are observed from the hydrolysis of di or
The tetraalkylstannanes react with protic acids to give tri-
organotin(IV) species with high yield at mild conditions. Breaking
of tinearyl bonds seems to be even much easier [1]. In the case of
triorganotin(IV) halides, the well known Kocheshkov reaction is
applied to prepare much polar di or monoorganotin(IV) halides
with rather low selectivity and usually drastic conditions and
long reaction time [2]. The reactivity of mixed alkyl-aryltin(IV)
compounds with mineral acids, mainly HCl in a polar solvent, is
of increasing interest due to an efficiency of products of this
reaction e trichlorotin(IV) substituted solid support in trans-
esterification processes [3] or ring opening polymerization of
monoorganotin(IV) compounds (Scheme 1B) e for hydrolysis of
NCNSn(n-Bu)Cl2 [7], LNCNSnF3[8] and LNCNSnCl3 [7]. On the other
hand, dimeric structure
NCNSnBr3 hydrolyzes to form
L
L
a
[HLNCNSnBr3(OH)]2 connected via OH/Br bridges (Scheme 1C) [9].
The triorganotin(IV) chlorides containing one C,N-chelating
ligand were also hydrolyzed with an excess of sodium hydroxide
[10]. The composition of the final reaction mixtures is strongly
dependent on the nature of the substituents bonded to the central
tin atom. The di-n-butyltin, dimethyltin and diphenyltin deriva-
tives undergo an equilibrium hydroxide 4 stannoxane (oxide),
where the tin-hydroxo species react spontaneously and reversibly
with atmospheric carbon dioxide to form the corresponding
bridged tin alkyl-carbonates. In comparison, the diphenyl deriv-
ative hardly reacts with CO2 and the di-t-butyl-substituted one
does not react at all and remains as a stable tin hydroxide.
Unsuccessful attempts to quarternize the nitrogen atom of the
C,N-chelating ligand with diluted HCl and HF were also discussed
there [10].
3
-caprolactone [4].
In previous works, we have described the product of hydrolysis
of LCNSnCl3 (where LCN is 2-(dimethylaminomethyl)phenyl) to be
a product of one ligand migration, [LCNSnCl4]ꢀ[HLCN2SnCl2]þ, where
one of the amino group of ligand was quarternized e protonated
(Scheme 1A) [5]. Similar results were found by Varga and Silvestru
for hydrolysis of LCNSnBr3 [6]. Both the hydrolytic products reveal
strong intermolecular bond between NH and the halide atom from
[LCNSnX4]ꢀ (X ¼ Cl, Br) fragment. In the case of bischelating
In this paper, we report on the reactivity of C,N-chelated tri and
diorganotin(IV) species (for 1H NMR numbering see Scheme 2) [11]
towards equimolar, as well as a high excess of mineral acids.
Reactivity of C,N-chelated organotin(IV) halides towards carboxylic
acids and various Lewis acids is also discussed.
* Corresponding author. Tel.: +420 466037151; Fax: þ420 466037068.
ꢁꢀ ꢀ
E-mail address: ales.ruzicka@upce.cz (A. Ruzicka).
0022-328X/$ e see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2010.08.006

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P. Svec et al. / Journal of Organometallic Chemistry 695 (2010) 2475e2485
Scheme 1. Hydrolytic products of di and monoorganotin(IV) halides.
2. Results and discussion
the sample was left for a couple of days in a closed vessel to give
L
CNPh2SnBr [11d]. This instability is probably a result of a concur-
The reactions of tri and diorganotin(IV) chlorides containing
C,N-chelating ligand(s) with mineral as well as Lewis acids have
been carried out in order to support literature results mentioned
above and to prepare di or monoorganotin(IV) halides by an easier
way.
rency of bases eNMe2 and eOMe and is confirmed by 1H and 119Sn
NMR spectroscopy as well as XRD analysis of the single crystals.
2.2. Preparation and structural characterization of zwitterionic
triorganostannates
2.1. General remarks
Prepared triorganostannates of the general formula
L
CNR2SnX$HX (where R ¼ n-Bu or Ph, X ¼ Cl, Br or I) were char-
L
CN(n-Bu)2SnCl, LCNPh2SnCl, (LCN)2(n-Bu)SnCl, LCN(n-Bu)SnCl2,
CNPhSnCl2 and (LCN)2SnCl2 were reacted with a slight excess of HCl,
acterized by multinuclear NMR spectroscopy and XRD techniques
(Fig. 1). In all these cases the central tin atom is five-coordinated
and reveals distorted trigonal bipyramidal geometry. According to
the Bent’s rule [12], both electronegative atoms X (X ¼ Cl, Br or I)
occupy axial positions and all three carbon atoms are situated in
equatorial positions, independently whether R is n-Bu or Ph. In the
L
an excess of HBr and HI, respectively, to give corresponding zwit-
terionic stannates (for numbering of compounds see Scheme 3). All
these reactions were carried out in the air and concentrated
aqueous hydrohalic acids were used. When HCl is used, satisfactory
yields (from 65% for
L
CNPh2SnCl$HCl up to 97% for LCN(n-
case of L
CN(n-Bu)2SnX$HX the interatomic distances Sn1eX1
Bu)2SnCl$HCl; all zwitterionic stannates are scripted in the form of
adducts e “substrate$acid” e for better clarity see also Scheme 3) of
desired zwitterionic stannates are obtained. The situation is much
more complicated when HBr or HI is used. When only 1.1 eq. of
respective hydrohalic acid was reacted with appropriate substrate
the formation of inseparable mixture of products was observed by
multinuclear NMR spectroscopy. To pass over this problem, an
excess (2.2 eq.) of hydrohalic acid needs to by applied. The stronger
acid displaces HCl and simultaneous formation of two new SneX
bonds (X ¼ Br or I) and the protonation of the CH2N(CH3)2 group
of the C,N-chelating ligand proceeds. The second problem is that
slow oxidation to elemental bromine or iodine occurs during the
reaction time. Into the bargain, the products need to be washed
with methanol to remove residual hydrohalic acid and/or
elemental X2 (X ¼ Br or I) and subsequent recrystallization of the
crude product is necessary. These operations decrease the overall
yield of the reaction (for example only 47% yield in the case of
(2.7292(9) Å for Cl, 2.8117(11) Å for Br and 2.9412(16) Å for I) and
Sn1eX2 (2.5412(9) Å for Cl, 2.7258(11) Å for Br and 2.8929(10) Å for
I) are unequal thanks to the presence of the strong intramolecular
NeH/X bond. The differences in these interatomic distances
decrease with increasing covalent radii [13] of X (0.1880 Å for
X ¼ Cl, 0.0859 Å for X ¼ Br and finally 0.0483 Å for X ¼ I). The
X1eSn1eX2 interatomic angle changes from 178.16(3)ꢁ for X ¼ Cl
to 174.39(3)ꢁ for X ¼ Br, and is very close to the ideal flat angle. The
sum of all equatorial CeSneC angles is 359.3ꢁ for
LCN(n-Bu)2SnCl$HCl (1), 359.8ꢁ for LCN(n-Bu)2SnBr$HBr (2) and
359.4ꢁ for LCN(n-Bu)2SnI$HI (3), respectively.
The 1H NMR spectra of all compounds studied display typical
broad signal of the NH moiety about 10.3 ppm which is within the
range characteristic for this bonding array. This chemical shift is
dependent on the deuterated solvent used and varies for example
from 11.06 ppm (in CDCl3) to 9.61 ppm (in CD3OD) in the case of 1
(for other compounds see Table 1). The presence of the direct NeH
bond causes splitting of the original singlet assigned to the CH2N
moiety to a doublet at ca. 4.3 ppm with coupling constant of about
5.2 Hz. The signal of the N(CH3)2 group is split into a doublet (with
coupling constant being about 4.8 Hz) for the same reason, too. The
L
CNPh2SnBr$HBr). The stannates bearing the phenyl substituent are
somewhat unstable in comparison with butyl-substituted stan-
nates. In the case of
CNPh2SnBr$HBr, an instability of this
compound in a coordinating solvent (MeOH) was observed when
L
Scheme 2. General 1H NMR numbering.

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P. Svec et al. / Journal of Organometallic Chemistry 695 (2010) 2475e2485
2477
Scheme 3. The reactivity of C,N-chelated organotin(IV) chlorides and general numbering of prepared compounds.
1H NMR chemical shift value of the N(CH3)2 group is strongly
influenced by deuterated solvent used. When compound 1 is
dissolved in CDCl3, the signal of the N(CH3)2 group is found at
2.68 ppm, which is in contrast with the value found in C6D6
(1.67 ppm). The position and the value of the 3J(119Sn, 1H) satellites
of the doublet of the H(60) signal in the 1H NMR spectra is another
useful tool for characterizing all C,N-chelated organotin
compounds. Prepared triorganostannates reveal the coupling
constant 3J(119Sn, 1H) being between 50 Hz up to 65 Hz (see
Experimental). On the other hand diorganostannates exhibit higher
coupling constant 3J(119Sn, 1H) within the range of 75e95 Hz, which
is in good agreement with previous published results [11bee].
The 119Sn NMR chemical shift values of these zwitterionic stannates
are shifted to lower frequencies than corresponding starting
L
CN(n-Bu)2SnX. The trend is that Dd 119Sn decreases with increasing
of the covalent radii of X (X ¼ Cl, Br or I) as shown in Table 1. In
addition, the 15N NMR spectra of 1 were recorder in DMSO-d6
(
d
¼ ꢀ337.5 ppm) and CD3OD ( ¼ ꢀ336.7 ppm). When measured
d
without the proton decoupling the signal splits to a doublet with
coupling constant J(1H, 15N) ¼ 74.6 Hz in DMSO-d6.
1
The vicinity of the central tin atom in LCNPh2SnCl$HCl (4) (Fig. 2)
reveals analogous geometry as in the case of mentioned
L
CN(n-Bu)2SnX$HX. The interatomic distances of Sn1eCl1 (2.7270
(7) Å) and Sn1eCl2 (2.5015(7) Å) are a little bit shorter than in 1
(2.7292(9) Å and 2.5412(9) Å, respectively). The Cl1eSn1eCl2
interatomic angle 168.76(2)ꢁ differs slightly from almost flat angle
in the case of 1 (178.16(3)ꢁ) described above. This deflection is
caused by the sterical hinderance of the two phenyl groups when
compared with the corresponding butyl-substituted zwitterionic
stannate. The sum of equatorial interatomic angles is 359.6ꢁ.
Unfortunately single crystals of
L
L
CNPh2SnBr$HBr (5) and
CNPh2SnI$HI (6) were not obtained.
According to literature [14], a high excess of HCl (20 eq.) was
used in the reaction with LCN(n-Bu)2SnCl in boiling methanol in
order to remove the butyl group. Surprisingly no signals of
L
CN(n-Bu)2SnCl$HCl as a by-product were observed in the 119Sn
NMR spectra. The only signal detected at ꢀ22.0 ppm can be
attributed by our opinion to a [(n-Bu)2SnCl3]ꢀ anion (controversial
case is that the published chemical shift for [(n-Bu)2SnCl3]ꢀ in the
119Sn NMR spectra of a mixture with [(n-Bu)2SnCl2F]ꢀ is ꢀ122 ppm
[15]) which is compensated with the N,N-dimethylbenzylammo-
nium as a counter cation. The chemical shift in the 119Sn NMR
spectrum is about 150 ppm lower than found for (n-Bu)2SnCl2
(
d
¼ 126.3 ppm) [16]. This suggestion is also supported by the 1H
NMR spectra pattern. The exactly same results were obtained when
gaseous HCl was bubbled through a diethyl ether solution of
L
CN(n-Bu)2SnCl for 10 min.
Fig. 1. Molecular structure of 1 (ORTEP view, 50% probability level). Hydrogen atoms
bonded to carbon atoms are omitted for clarity. Selected interatomic distances [Å] and
angles [ꢁ]: Sn1eCl1 2.7292(9), Sn1eCl2 2.5412(9), Sn1eC1 2.154(3), Sn1eC10 2.138(4),
Sn1eC14 2.141(3), Cl1eSn1eCl2 178.16(3), Cl1eSn1eC1 87.63(8), Cl2eSn1eC1 90.24
(8), C1eSn1eC10 127.92(13), C1eSn1eC14 111.30(13), C10eSn1eC14 120.30(16).
H-bonding: N1eCl1 3.057(2), N1eH1/l1 170.4. For 2: Sn1eBr1 2.8117(11), Sn1eBr2
2.7258(11), Sn1eC1 2.155(7), Sn1eC10 2.142(9), Sn1eC14 2.160(8), Br1eSn1eBr2
174.39(3), Br1eSn1eC1 88.8(2), Br2eSn1eC1 86.4(2), C1eSn1eC10 115.9(3),
C1eSn1eC14 126.2(3), C10eSn1eC14 117.7(3). H-bonding: N1eBr1 3.234(6),
N1eH1/Br1 167.0. For 3: Sn1eI1 2.9412(16), Sn1eI2 2.8929(10), Sn1eC1 2.165(9),
Sn1eC10 2.152(13), Sn1eC14 2.148(10), I1eSn1eI2 176.73(5), I1eSn1eC1 87.3(2),
I2eSn1eC1 91.1(2), C1eSn1eC10 122.3(4), C1eSn1eC14 113.4(4), C10eSn1eC14 123.7
(4). H-bonding: N1eI1 3.243(7), N1eH1/I1 174.2.
Since the reaction of LCN(n-Bu)2SnCl with only one equivalent
of HNO3 gave no reproducible results, the excess of HNO3 was
used. The reaction of LCN(n-Bu)2SnCl with 5 eq. of HNO3 ended
analogously by the formation of N,N-dimethylbenzylammonium
connected by one H-bond to a counter anion of empirical formula
[(n-Bu)2SnCl(NO3)2]ꢀ (Fig. 3). Surprisingly the SneCl bond remained
untouched. According to s-descriptor, the coordination geometry of
the central tin atom in the solid state can be described as a distorted
square pyramidal with O1, O4, C10 and C14 atoms in the base of the
pyramidand the Cl1 as the top atom. Computed s-descriptor for five-

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P. Svec et al. / Journal of Organometallic Chemistry 695 (2010) 2475e2485
Table 1
Selected 1H and 119Sn NMR chemical shift values of prepared compounds with coupling constants of doublets in Hz in parentheses.
a
Compound
LCN(n-Bu)2SnCl$HCl
Solvent
NH
H(60)
CH2N
N(CH3)2
2.68 (4.8)
119Sn
Dd 119Sn
CDCl3
C6D6
CD3OD
DMSO-d6
CDCl3
C6D6
DMSO-d6
CDCl3
CDCl3
CDCl3
DMSO-d6
CDCl3
DMSO-d6
CDCl3
CDCl3
THF-d8
CDCl3
DMSO-d6
CD3OD
C6D6
11.06
10.81
9.61
10.17
10.44
10.43
9.89
10.14
10.66
10.55
9.83
10.32
9.82
10.47
10.28
10.15
11.80
10.77
ed
7.84 (6.7)
8.11 (7.3)
7.69 (7.0)
7.64 (6.1)
7.85 (7.2)
8.10 (7.3)
7.63 (5.9)
7.67 (7.3)
7.73 (7.2)
7.64 (6.2)
7.63 (7.3)
7.77 (7.2)
7.67 (6.5)
7.79 (7.6)
7.61 (6.9)
7.51 (6.2)
3.83 (5.4)
3.40 (5.5)
4.39 (5.6)
4.36 (4.9)
3.75 (4.8)
3.44 (5.5)
4.39 (5.5)
4.16 (4.6)
4.57 (br)
4.06 (5.2)
4.34 (5.5)
4.05 (5.1)
4.37 (5.0)
4.55 (6.6)
4.51 (5.5)
4.60 (6.1)
4.03 (147.1)/3.39(94.4)
4.51 (5.2)
4.48 (s)
ꢀ105.1
ꢀ133.7
ꢀ77.5/ꢀ336.7b
ꢀ137.3/ꢀ337.5b
ꢀ94.2
ꢀ57.6
ꢀ84.5
ꢀ25.5
ꢀ80.0
ꢀ54.5
ꢀ83.9
ꢀ76.2
ꢀ28.1
ꢀ65.9
ꢀ48.4
ꢀ69.1
ꢀ32.8
ꢀ56.8
ꢀ98.5
ꢀ91.7
ꢀ82.5
ꢀ6.9
1.67 (4.9)
2.87 (4.7)
2.76 (4.6)
2.64 (4.8)
1.72 (4.9)
2.78 (4.6)
2.75 (4.0)
2.87 (4.6)
2.31 (5.0)
2.41 (4.7)
2.18 (4.2)
2.43 (4.5)
2.75 (5.1)
2.82 (4.7)
2.85 (5.2)
2.53/1.64c (br)
2.72 (4.6)
2.82 (s)
L
CN(n-Bu)2SnBr$HBr
ꢀ125.7
ꢀ121.1
ꢀ61.0
L
L
L
CN(n-Bu)2SnI$HI
CN(n-Bu)2Sn(OCOCF3)$CF3COOH
CNPh2SnCl$HCl
ꢀ130.1
ꢀ224.9
ꢀ252.0
ꢀ213.8
ꢀ238.8
ꢀ298.4
ꢀ196.0
ꢀ262.7
ꢀ125.0
ꢀ216.4
ꢀ188.6
ꢀ401.6
L
CNPh2SnBr$HBr
LCNPh2SnI$HI
L
L
CN(n-Bu)SnCl2$HCl
CNPhSnCl2$HCl
(LCN)2(n-Bu)SnCl$HCl
(LCN)2(n-Bu)SnCl$2HCl
8.22/8.16c (br)
7.84 (7.3)
7.88 (6.8)
e
c
ꢀ99.4
ꢀ72.1
e
[HLCNH]þ[Bu2SnCl(NO3)2]e
9.16
3.48 (5.4)
2.03 (5.0)
Dd 119Sn are relative to corresponding C,N-chelated organotin halides or trifluoroacetate (e.g. LCNPh2SnBr$HBr is relative to LCNPh2SnBr; except of [HLCNH]þ\Bu2SnCl
a
(NO3)2]e).
b
c
15N NMR chemical shift values.
Signals are split due to the presence of two unequivalent H(60) protons and NCH2 and N(CH3)2 groups, for details see text.
Signal disappears probably due to fast D for H exchange.
d
coordination
s
¼ (
a
e
b
)/60 ¼ (160.73 e 147.21)/60 ¼ 0.23 (extreme
addition, the 13C and 19F NMR spectra of this compound in CDCl3
were recorded in order to evaluate the presence of the CF3COOꢀ
groups. There are two characteristic quartets in the 13C NMR
spectra, first one at 162.1 ppm (COO) with coupling constant 2J(19F,
13C) ¼ 41.1 Hz and the second one at 115.9 ppm with much higher
coupling constant 1J(19F, 13C) ¼ 288.2 Hz (CF3). The only one signal
for both CF3 groups was found in the 19F NMR spectra at ꢀ74.7 ppm.
These data indicate the equality of both CF3COOꢀ substituents in
solution. The second pathway for the preparation of this compound
is via the reaction of LCN(n-Bu)2Sn(OCOCF3), prepared by the reac-
tion of LCN(n-Bu)2SnCl and CF3COOAg [19], with only 1.1 eq. of
forms:
s
¼ 0.00 for square pyramid and 1.00 for trigonal bipyramid)
[17]. The O2 and O5 atoms are 2.8492(19) Å and 2.7873(19) Å,
respectively, distant from Sn1 and are within the range of the sum of
van der Waals (3.58 Å) and covalent radii (2.05 Å) [13,18]. The 119Sn
NMR chemical shift value at ꢀ401.6 ppm matches with seven-
coordinated tin which may be caused by bonding equality of both
(NO3)ꢀ groups in the solution in the NMR time scale.
Reaction of LCN(n-Bu)2SnCl with CF3COOH as a strong carboxylic
acid has been also studied. This involves the reaction of the
L
CN(n-Bu)2SnCl with the excess of CF3COOH (2.2 eq.) resulting in
the formation of desired LCN(n-Bu)2SnOC(O)CF3$CF3COOH (8). The
molecular structure and parameters of the multinuclear NMR
spectra are similar to triorganostannates discussed vide supra. In
Fig. 3. Molecular structure of 7 ½C6H6 (ORTEP 40% probability). Benzene molecule and
hydrogen atoms bonded to carbon atoms are omitted for clarity. Selected interatomic
distances [Å] and angles [ꢁ]: Sn1eCl1 2.4052(7), Sn1eO1 2.3108(17), Sn1eO2 2.8492
(19), Sn1eO4 2.2546(17), Sn1eO5 2.7873(19), Sn1eC10 2.112(3), Sn1eC14 2.105(3),
O1eSn1eO4 160.73(7), O4eSn1eO5 49.68(6), O1eSn1eO5 149.58(6), O1eSn1eCl1
78.87(5), C10eSn1eC14 147.21(10), Cl1eSn1eO4 81.86(5), Cl1eSn1eO5 131.54(4).
H-bonding: N1eO1 2.893(3), N1eH1/O1 149.7.
Fig. 2. Molecular structure of 4 (ORTEP view, 50% probability level). Hydrogen atoms
bonded to carbon atoms are omitted for clarity. Selected interatomic distances [Å] and
angles [ꢁ]: Sn1eCl1 2.7270(7), Sn1eCl2 2.5015(7), Sn1eC1 2.156(3), Sn1eC10 2.148(2),
Sn1eC16 2.162(2), Cl1eSn1eCl2 168.76(2), Cl1eSn1eC1 82.05(6), Cl2eSn1eC1 87.31
(7), C1eSn1eC10 120.49(9), C1eSn1eC16 124.73(9), C10eSn1eC16 114.38(9).
H-bonding: N1eCl1 3.083(2), N1eH1/Cl1 172.0.

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P. Svec et al. / Journal of Organometallic Chemistry 695 (2010) 2475e2485
2479
CF3COOH. This result is confirmed by multinuclear NMR spectros-
copy. The tin atom is five-coordinated once again in the solid state
and posses the geometry of distorted trigonal bipyramid (Fig. 4)
with the sum of all CeSneC interatomic angles being practically
360ꢁ (359.99ꢁ). The interatomic angle O1eSn1eO3 (174.62(12)ꢁ) is
closed to the ideal 180ꢁ angle.
were used (H2SO4 and H3PO4, respectively) the reaction always
ended with a mixture of unidentified inseparable products, which
was confirmed by 1H and 119Sn NMR spectroscopy. In some cases
the formation of free N,N-dimethylbenzylammonium can be
deduced from 1H NMR spectra indicating some parallelism with the
reaction of excess of HNO3 with LCN(n-Bu)2SnCl.
On the other hand, when weak carboxylic acids, such as
PhCOOH, FcCOOH (where Fc is ferrocenyl) and picric acid, were
used the reactions did not proceed at all and only starting
substrates together with respective acids were identified in the
reaction mixture by multinuclear NMR spectroscopy. Elevating the
temperature had no effect on the reaction progress. The CF3SO3H
and HBF4 acids were reacted with LCN(n-Bu)2SnCl to give presum-
ably ionic species. According to the 1H and 119Sn NMR spectroscopy,
there is definitely no starting LCN(n-Bu)2SnCl in the reaction
mixture. There are characteristic doublets of the protonated CH2N
and N(CH3)2 moieties but incredibly no signals of the þNH moieties
were found around 10 ppm in the 1H NMR spectra where expected.
The only signals detected by 119Sn NMR spectroscopy at 30.5 ppm
(for reaction of CF3SO3H) and 60.0 ppm (for reaction of HBF4) can be
probably assigned to in-situ generated ionic tin-containing species.
All these spectra were recorded in CDCl3. These results were
reproduced for the second time but still no single crystals have
been grown from the reaction mixtures up to now.
The last triorganostannates prepared are the (LCN)2(n-Bu)
SnCl$HCl (9) and (LCN)2(n-Bu)SnCl$2HCl (10). Unfortunately only
the single crystals suitable for XRD analysis of 10 were obtained
(Fig. 5). Although compound 9 was isolated as a white crystalline
solid, it became oily when stored at room temperature in a glass
vial. The tin atom in compound 10 in solid state is five-coordinated
as in vide supra described zwitterionic stannates and reveals a dis-
torted trigonal bipyramidal geometry, too. Cl1 and Cl2 atoms are
placed in the axial positions with C1, C10 and C19 atoms occupying
the equatorial sites. The Sn1eCl1 (2.6423(7) Å) and Sn1eCl2
(2.5848(6) Å) interatomic distances are not equal. The
Cl1eSn1eCl2 interatomic angle (176.14(4)ꢁ) differs only a little
from the ideal flat angle. The sum of equatorial interatomic angles
CeSneC is 359.65ꢁ. There are two intramolecular NeH/Cl bonds
in the molecule of 10. The Cl3 atom is out of the primary coordi-
nation sphere of the tin atom (interatomic distance
Sn1eCl3 ¼ 7.4119(6) Å). 1H NMR spectra of both 9 and 10 exhibit
characteristic signal of the NH proton at 11.80 ppm (in CDCl3) and
10.77 ppm (in DMSO-d6 due to insolubility of 10 in chloroform),
respectively. The 1H NMR spectrum of 9 is relatively complicated
since two unequivalent (protonated and not protonated) ligands
are present. This results in characteristic 1H NMR pattern having
two broad doublets at 4.03 ppm (CH2Nþ, J ¼ 147.1 Hz) and 3.39 ppm
(CH2N, J ¼ 94.4 Hz). Another two different broad signals at
2.53 ppm for Nþ(CH3)2 and 1.64 ppm for N(CH3)2 groups are
observed. Splitting of the signals of the protonated CH2Nþ(H)(CH3)2
moiety into doublets is not evident probably due to the dynamic
character of the whole molecule. The value of 119Sn NMR chemical
Reaction of LCN(n-Bu)2SnF with HCl, HBr and HI led to the
formation of HF and respective triorganotin(IV) halide. These
results were confirmed by 1H and 119Sn NMR spectroscopy. Reac-
tion of LCN(n-Bu)2SnF with HF is a complex process and no repro-
ducible results were obtained despite several more reactions were
carried out. The hydrofluoric acid is definitely not strong enough
both to break the intramolecular SneN bond and to protonate the
nitrogen atom of the C,N-ligand since no signals of the CH2Nþ(H)
(CH3)2 group were observed in the 1H NMR spectra. On the other
hand, when stochiometric amounts of dihydric or trihydric acid
Fig. 5. Molecular structure of 10 (ORTEP view, 50% probability level). Only hydrogen
atoms bonded to nitrogen atoms are depicted for clarity. Selected interatomic
distances [Å] and angles [ꢁ]: Sn1eCl1 2.6423(7), Sn1eCl2 2.5848(6), Sn1eCl3 7.4119(6),
Sn1eC1 2.146(2), Sn1eC10 2.157(2), Sn1eC19 2.145(2), Cl1eSn1eCl2 176.14(4),
Cl1eSn1eC1 89.08(7), Cl1eSn1eC10 88.18(7), Cl1eSn1eC19 86.94(7), Cl2eSn1eC1
87.07(7), Cl2eSn1eC10 93.05(7), Cl2eSn1eC19 95.57(7), C1eSn1eC10 112.47(9),
C1eSn1eC19 126.60(9), C10eSn1eC19 120.58(9). H-bonding: N1eCl1 3.096(2),
N2eCl2 3.074(2), N1eH1/Cl1 172.4, N2eH2/Cl2 172.3.
Fig. 4. Molecular structure of 8 (ORTEP view, 50% probability level). Hydrogen atoms
bonded to carbon atoms are omitted for clarity. Selected interatomic distances [Å] and
angles [ꢁ]: Sn1eO1 2.232(2), Sn1eO3 2.334(2), Sn1eC1 2.153(3), Sn1eC10 2.127(3),
Sn1eC14 2.140(4), O1eSn1eO3 174.58(8), O1eSn1eC1 87.8(10), O3eSn1eC1 86.69
(10), C1eSn1eC10 113.19(12), C1eSn1eC14 124.04(12), C10eSn1eC14 122.77(13).
H-bonding: N1eO3 2.771(3), N1eH1/O3 156.6.

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shift at ꢀ125.0 ppm (CDCl3) for 9 differs only by ꢀ6.9 ppm relative
to (LCN)2(n-Bu)SnCl (
d
¼ ꢀ118.1 ppm). On the other hand, there is
a ꢀ99.4 ppm difference of doubly protonated 10 (
d
¼ ꢀ216.4 ppm in
DMSO-d6) relative to starting (LCN)2(n-Bu)SnCl.
2.3. Preparation and structural characterization of zwitterionic
diorganostannates
In order to expand the set of prepared zwitterionic tri-
organostannates to diorganostannates, the reactivity of C,N-che-
lated diorganotin(IV) chlorides with hydrochloric acid was the next
task. According to previous results of the reactions of (LCN)2(n-Bu)
SnCl with HCl, doubly C,N-chelated tin(IV) dichloride was treated
with 1 eq. and 2 eq. of HCl, respectively. Unfortunately both reac-
tions resulted in a mixture of products. Into the bargain, the
products dissolve only in DMSO. In both cases the 1H NMR spectra
in DMSO-d6 are complicated to be interpreted in a right way. The
signal at 10.33 ppm indicates the presence of quarternized
CH2Nþ(H)(CH3)2 moiety. In the 119Sn NMR spectra of the reaction of
(LCN)2SnCl2 with two equivalents of HCl the original signal of
(LCN)2SnCl2 at ꢀ266.6 ppm in DMSO-d6 disappears and two new
signals at ꢀ434.6 and ꢀ454.1 ppm in 3:1 ratio arise. When only
1 eq. of HCl was used signals at ꢀ434.6 and ꢀ454.1 ppm were
detected again, changing only the ratio of the signals to 6:1. The
signal at ꢀ434.6 ppm was attributed to monoorganotin compound
Fig. 7. Molecular structure of 12$C6H6 (ORTEP view, 40% probability level). Benzene
molecule and hydrogen atoms bonded to carbon atoms are omitted for clarity. Selected
interatomic distances [Å] and angles [ꢁ]: Sn1eCl1 2.5920(7), Sn1eCl2 2.5019(7),
Sn1eCl3 2.3628(7), Sn1eC1 2.140(2), Sn1eC10 2.126(2), Cl1eSn1eCl2 173.50(2),
Cl1eSn1eCl3 85.97(2), Cl2eSn1eCl3 89.29(2), Cl1eSn1eC1 89.22(7), C1eSn1eC10
120.63(9), C1eSn1eCl3 122.24(6), C10eSn1eCl3 117.06(7). H-bonding: N1eCl1 3.157
(2), N1eH1/Cl1 155.5.
axial chlorines (SneClax distances being 2.6596(5) Å and 2.5061
(6) Å, respectively) in 11. The same trend is clearly seen for 12, too
(SneCleq ¼ 2.3628(7) Å, SneClax distances being 2.5920(7) Å and
2.5019(7) Å, respectively). The interatomic distances between axial
chlorine atoms and the central tin atom are somewhat shorter or
equal for both 11 and 12 when compared to corresponding inter-
atomic distances in triorganotin stannates (Sn1eCl1 2.7292(9) Å
and Sn1eCl2 2.5412(9) Å for 1; Sn1eCl1 2.7270(7) Å and Sn1eCl2
2.5015(7) Å for 4). The sum of interatomic angles among all atoms
in the equatorial plane is 358.91ꢁ for 11 and 359.93ꢁ in the case of
12. The corresponding values of interatomic angles Cl1eSn1eCl3
(177.40(2)ꢁ) for 11 and Cl1eSn1eCl2 (173.50(2)ꢁ) for 12, respec-
tively) are influenced by the sterical hinderance of the respective
organic substituent and are attacking the value of ideal flat angle.
This interatomic angle in 11 is very close to corresponding angle in
the triorganotin zwitterionic stannate 1 (Cl1eSn1eCl 178.16(3)ꢁ)
discussed above. Due to the presence of only one sterically
hindering phenyl substituent in 12, the value of the Cl1eSn1eCl2
angle (173.50(2)ꢁ) is much more closer to 180ꢁ in comparison with
4 (Cl1eSn1eCl2 168.76(2)ꢁ) bearing two phenyl substituents. The
presence of the direct NeH bond is confirmed by 1H NMR spec-
troscopy since signals of the NH protons and two doublets assigned
to protonated CH2N and N(CH3)2 moieties can be found in each
spectra. The 119Sn NMR spectra reveal shift of the signals to lower
frequencies (ꢀ196.0 ppm in CDCl3 for 11 and e262.7 ppm in THF-d8
for 12) relative to starting LCN(n-Bu)SnCl2 (ꢀ104.3 ppm in CDCl3)
and LCNPhSnCl2 (ꢀ180.2 ppm in THF-d8), respectively.
L
CNSnCl3 [20] and the signal at ꢀ454.1 ppm can be thus assigned
to presumably protonated species LCNSnCl3$HCl. In summary,
(LCN)2SnCl2 reacts with HCl to give a mixture of LCNSnCl3 and
L
CNSnCl3$HCl independently on stoichiometry of the reaction. Due
to poor solubility in other common organic solvents no single
crystals of these compounds were obtained.
The situation becomes conspicuous when LCN(n-Bu)SnCl2 or
L
CNPhSnCl2 is used instead of (LCNCN)2SnCl2. Owing to the presence
of only one LCN ligand no mixture of products of the reaction with
concentrated aqueous HCl is observed. The reactions proceed
perfectly to form corresponding zwitterionic stannates which are
isolated as white crystalline solids.
The coordination geometry of the central tin atom in both
L
CN(n-Bu)SnCl2$HCl (11) (Fig. 6) and LCNPhSnCl2$HCl (12) (Fig. 7)
can be evidently defined as a distorted trigonal bipyramid. The
SneCl interatomic distance of equatorial chlorine atom
(SneCleq ¼ 2.3740(6) Å) is naturally shorter when compared to
2.4. Unexpected product of reaction of triphosgene with
L
CN(n-Bu)2SnF
We have reported on use of LCN(n-Bu)2SnF for preparation of
acyl fluorides a fluoroformates from their chloride precursors
recently [21]. These reactions concerned fluorination of phosgene,
diphosgene as well as triphosgene. In all three latter cases the
formation of COF2 in the reaction mixture is consequently
confirmed by multinuclear NMR spectroscopy as expected [21]. On
the other hand, when reaction of triphosgene with six equivalents
of LCN(n-Bu)2SnF was carried out in toluene on the air, crystals of
[HLCN(n-Bu)2SnCl]2[SiF6] (13) as a minor by-product were isolated
from the reaction mixture in 14% yield (relative to starting LCN(n-
Bu)2SnF).
Fig. 6. Molecular structure of 11 (ORTEP view, 50% probability level). Hydrogen atoms
bonded to carbon atoms are omitted for clarity. Selected interatomic distances [Å] and
angles [ꢁ]: Sn1eCl1 2.6596(5), Sn1eCl2 2.3740(6), Sn1eCl3 2.5061(6), Sn1eC1 2.1396
(19), Sn1eC10 2.136(2), Cl1eSn1eCl3 177.40(2), Cl1eSn1eCl2 86.41(2), Cl2eSn1eCl3
92.22(2), Cl1eSn1eC1 86.50(5), C1eSn1eC10 132.65(8), C1eSn1eCl2 115.26(5),
C10eSn1eCl2 111.00(6). H-bonding: N1eCl1 3.0840(18), N1eH1/Cl1 175.4.

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2481
The following reaction mechanism is proposed for the forma-
tion of 13 (Scheme 4): in the first step, the complete fluorination of
the starting triphosgene takes place followed by the formation of
the fluorophosgene that dissolves immediately in toluene. Hydro-
lysis of the fluorophosgene yields hydrogen fluoride that attacks
the glass surface giving hexafluorosilicate acid. The hexa-
fluorosilicate acid finally reacts with LCN(n-Bu)2SnCl that is still
present in the reaction mixture forming thus unexpected product
13. Unfortunately compound 13 is unstable and decomposes to
L
CN(n-Bu)2SnCl, SiF4 and hydrofluoric acid when dissolved in
deuterated chloroform since 1H and 119Sn NMR spectra reveal only
signals that correspond to pure LCN(n-Bu)2SnCl. This conclusion is
further supported by 19F NMR spectroscopy since no signals of the
hexafluorosilicate anion were found in the 19F NMR spectrum.
Compound 13 dissolves poorly even in C6D6 and therefore no NMR
spectra in non-polar solvents were recorded.
The single crystals of 13 (Fig. 8) were obtained from a concen-
trated reaction mixture which was left for one week in a glass flask.
Both Sn1 and Sn2 tin atoms reveals distorted trigonal bipyramidal
geometry with nearly octahedral SiF26e anion connecting both tri-
organotin(IV) moieties. The Sn1eF3 (2.485(3) Å) and Sn2eF1
(2.400(3) Å) distances are somewhat unequal. On the other hand,
the Sn1eCl1 (2.4568(18) Å) and Sn2eCl2 (2.4785(18) Å) distances
are comparable in 13. The sum of equatorial CeSneC angles is
represented by 357.3ꢁ and is identical for both CeSn1eC and
CeSn2eC. The ideal octahedral geometry of the SiF26e anion is
cracked up due to the existence of two SneFeSi bridges length-
ening thus the Si1eF1 (1.738(4) Å) and Si1eF3 (1.740(4) Å) bonds.
The four remaining Si1eF bonds are about 0.08 Å shorter than
Si1eF1 and Si1eF3 bonds (see Fig. 8). As shown in Fig. 8, there are
also two multicentric NeH/F intramolecular bonds strongly
influencing the geometry of the SiF26e anion.
Fig. 8. Molecular structure of 13 (ORTEP view, 30% probability level). Hydrogen atoms
bonded to carbon atoms are omitted for clarity. Selected interatomic distances [Å] and
angles [ꢁ]: Sn1eCl1 2.4568(18), Sn2eCl2 2.4785(18), Sn1eF3 2.485(3), Sn2eF1 2.400
(3), Sn1eC1 2.150(5), Sn2eC21 2.152(6), Sn1eC10 2.135(7), Sn2eC210 2.145(7),
Sn1eC14 2.148(7), Sn2eC214 2.122(7), Si1eF1 1.738(4), Si1eF2 1.654(4), Si1eF3 1.740
(4), Si1eF4 1.670(4), Si1eF5 1.647(4), Si1eF6 1.657(4), Cl1eSn1eF3 172.75(9),
Cl2eSn2eF1 173.86(9), Cl1eSn1eC1 92.03(16), Cl2eSn2eC21 92.37(16), Cl1eSn1eC10
101.3(2), Cl2eSn2eC210 97.32(17), Cl1eSn1eC14 99.11(17), Cl2eSn2eC214 97.1(2),
C1eSn1eF3 81.13(17), C21eSn2eF1 81.53(18), F1eSi1eF2 176.1(2), F3eSi1eF5 176.9
(2), F4eSi1eF6 174.0(2), Sn1eF3eSi1 140.30(18), Sn2eF1eSi1 141.96(19). H-bonding:
N1eF2 3.157(6), N1eH61/F2 125.4, N1eF3 2.827(6), N1eH61/F3 155.5, N1eF6 2.836
(6), N1eH61/F6 133.3, N2eF1 2.817(6), N2eH62/F1 155.4, N2eF4 2.909(6),
N2eH62/F4 135.0, N2eF5 3.233(6), N2eH62/F5 123.9.
reactivity of C,N-chelated organotin(IV) halides with other Lewis
acids was also studied. Excess of TiCl4 used in mentioned reac-
tions led to the formation of ionic [LCN(n-Bu)2Sn]þ[Ti2Cl9]ꢀ.
Unfortunately when AlCl3 was used instead of TiCl4 the reaction
did not take place. When LCN(n-Bu)2SnCl was treated with AlBr3
(1:1 ratio) only simple chlorine for bromine substitution occurred
According to the literature, the free SiF26e anion posses the Oh
symmetry and the corresponding vibrational modes are: 1A1g
(R) þ 1Eg (R) þ 1F2g (R) þ 2F1u (IR) þ 1F2u (IR). Indeed, only three
characteristic bands were observed in the Raman spectra of the
SiF26e anion at around 670 (s, ysSieF), 470 (w, yasSieF) and 390 (m,
FeSieF) cmꢀ1 [22]. In the case of isolated solid complex 13 the
forming thus corresponding
L
CN(n-Bu)2SnBr which was
d
confirmed by NMR experimental data found in literature [24]. In
this particular case, AlBr3 served as a common brominating agent
(proven by 1H and 119Sn NMR spectroscopy). The Kocheshkov
reactions of various C,N-chelated organotin(IV) halides with
SnCl4 and SnBr4 were also studied. LCN(n-Bu)2SnCl and
characteristic bands were not observed since only bands situated at
338, 509 and 602 cmꢀ1 were found which are closest to previously
published results. This disparity may be caused by the presence
multiple SieF/H bonds. The vibrational mode of the molecule is
also influenced by two SneFeSi bonds that crumple the symmetry
of the SiF26e anion. Other bands detected by Raman spectroscopy
can be assigned to vibrations of remaining bonds in the molecule.
L
CNPh2SnCl were selected as an exemplary substrates. These
substrates were reacted with varying ratio of SnCl4 and SnBr4.
The formation of mixtures of various C,N-chelated organotin(IV)
halides and non-chelated organotin(IV) halides was observed in
all cases. The assay of corresponding products in the reaction
mixtures was elucidated by 1H and 119Sn NMR spectroscopy. All
recorded NMR spectra were then confronted with known
experimental data published in literature e for details see
Experimental.
2.5. Reactions of C,N-chelated organotin(IV) compounds with
various Lewis acids
Based on previously published results concerning reactions of
L
CN(n-Bu)2SnCl and LCN(n-Bu)2SnCp with TiCl4 [23], further
Scheme 4. Proposed sequences of reaction of LCN(n-Bu)2SnF with triphosgene.

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2.6. Thermal stability and possible use of prepared zwitterionic
triorganostannates
character of the X atom) the more 1H NMR chemical shift values of
the NH moiety are shifted to lower frequencies. The last example of
attempt to correlate chemical hardness
ionization energy in kJ/mol and A is the electron affinity in kJ/mol of
h
(
h
¼ (I e A), where I is the
To test the thermal stability of prepared compounds the DSC
methods were applied. 1, 2 and 4 were heated in an open vessel
10 ꢁC/min. In the cases of 1-butyl-substituted compounds, only
a melting of solid material was observed. In the case of 4 two
different reactions were detected, loss of benzene molecule led to
the formation of LCNPhSnCl2 (proven by 1H and 119Sn NMR spec-
troscopy) and the second one reaction is a simple loss of HCl to give
the X atom) and difference in interatomic distances
D
x (
D
x ¼ d
(Sn1 e X1) e d(Sn1 e X2)) for LCN(n-Bu)2SnX$HX (X ¼ Cl, Br and I) is
depicted in Diagram S4. With increasing the value of
h
(e.g. with
increasing electronegativity of the X atom) the
increasing, too.
Dx values are
L
CNPh2SnCl. These two processes are in approx. molar ratio of 4:1
3. Experimental
according to 1H and 119Sn NMR spectroscopy.
In order to explore possible use of prepared zwitterionic stan-
nates as a well defined transferors of mineral acids to organic
solvents, the attempts to deprotect 1-N-(4,40-dimethoxytrityl)
3.1. NMR spectroscopy
The NMR spectrawere recorded from solutionsin CDCl3, benzene-
d6, DMSO-d6, THF-d8 or CD3OD on a Bruker Avance 500 spectrometer
substituted
reaction of 1-N-(4,40-dimethoxytrityl)-protected
1, the unprotected
in DMSO extract in w30% yield at room temperature. When the
reaction mixture was refluxed for 10 min in toluene, it became
D
-(þ)-biotin by 1 have been carried out. After 1 h of
(equipped with Z-gradient
5
mm probe) at frequencies 1H
D
-(þ)-biotin with
(500.13 MHz), 13C{1H} (125.76 MHz), 15N{1H} (50.65 MHz), 19F{1H}
(470.57 MHz) and 119Sn{1H} (186.50 MHz) at 295 K. The solutions
were obtained by dissolving of approximately 40 mg of each
compoundin0.6 mLofdeuteratedsolvents. The values of1H chemical
D-(þ)-biotin was obtained as a pure compound
turbid as the insoluble unprotected
Essentially quantitative yield of unprotected
obtained in 1 h by this method. All these reactions were monitored
by multinuclear NMR spectroscopy and all recorded 1H and 13C
NMR spectra were confronted with the SigmaeAldrich NMR
spectra library [25].
D
-(þ)-biotin precipitated.
shifts were calibrated to residual signals of CDCl3 (
d
(1H) ¼ 7.27 ppm),
D
-(þ)-biotin was
benzene-d6 (
d
(1H) ¼ 7.16 ppm), DMSO-d6 (
d
(1H) ¼ 2.54 ppm), THF-d8
(d
(1H) ¼ 3.57 ppm) or CD3OD (
d
(1H) ¼ 3.34 ppm). The values of 13
C
chemicalshiftswerecalibratedtosignalsofCDCl3 (
d(
13C)¼ 77.2ppm),
15N chemical shifts to external neat nitromethane (
d
(
15N) ¼ 0.0 ppm).
The 119Sn chemical shift values are referred to external neat tetra-
methylstannane (
d(
119Sn) ¼ 0.0 ppm). Positive chemical shift values
2.7. Correlations concerning the experimental data of a set of
prepared triorganostannates
denote shifts to the higher frequencies relative to the standards.119Sn
NMR spectra were measured using the inverse gated-decoupling
mode.
Based on collected experimental data for zwitterionic stannates
of general formula LCN(n-Bu)2SnX$HX (X ¼ Cl, Br and I), some
correlations concerning 1H NMR chemical shift values of the NH
group (in CDCl3), SneX bond lengths, NeH/X interatomic
3.2. Crystallography
distances, pKA of used hydrohalic acids and chemical hardness
h
The X-ray data (Tables S1eS3, see Supporting information) for
colourless crystals of all compounds were obtained at 150 K using
Oxford Cryostream low-temperature device on a Nonius KappaCCD
were studied. All correlation diagrams are available in the
Supporting information. In cases of phenyl-substituted compounds,
the collected experimental data were not complete due to insolu-
bility of some products in one of solvents used in the n-butyl series.
Furthermore, the crystal structure of some products was not
determined by XRD analyses since no suitable single crystals were
obtained.
diffractometer with MoKa radiation (
l
¼ 0.71073 Å), a graphite
monochromator, and the and scan mode. Data reductions were
4
c
performed with DENZO-SMN [26]. The absorption was corrected by
integration methods [27]. Structures were solved by direct methods
(Sir92) [28] and refined by full matrix least-square based on F2
(SHELXL97) [29]. Hydrogen atoms were mostly localized on
a difference Fourier map, however to ensure uniformity of the
treatment of the crystal, all hydrogen atoms were recalculated into
idealized positions (riding model) and assigned temperature
factors Hiso(H) ¼ 1.2 Ueq(pivot atom) or of 1.5 Ueq for the methyl
moiety with CeH ¼ 0.96, 0.97, and 0.93 Å for methyl, methylene
and hydrogen atoms in aromatic rings, respectively, and 0.82 Å for
NeH groups.
Generally, one could evaluate the strength of used acid in
respective solvent by the d
(1H) value of the signal of the NH frag-
ment in 1H NMR spectra. There is obvious linear correlation
between the 1H NMR chemical shift values of the NH group and pKA
of used hydrohalic acids as depicted in Diagram S1. The strength of
the acid used (represented by its pKA values) influences the 1H NMR
chemical shift value of the NH moiety. The stronger the acid is more
the signal of the NH moiety shifts to lower frequencies. For
example, in the case of 1 (pKA(HCl) ¼ ꢀ7) the signal of the NH
moiety is found at 11.06 ppm. On the other hand, for
3
3.3. DSC
(pKA(HI) ¼ ꢀ10) the signal of the NH moiety shifts to 10.14 ppm in
CDCl3. The second linear correlation concerns the 1H NMR chemical
shift values of the NH fragment and differences in the interatomic
The calorimetric measurements were performed by Mettler DSC
12E calorimeter in perforated alumina pans using heating rate
10 ꢁC/min in the temperature range 20e180 ꢁC. Calorimeter was
calibrated with indium and sapphire. Samples were weighted
(Sartorius R 160 P) before and after DSC measurements.
distances
decreasing value of
D
x (
D
x ¼ d(Sn1 e X1) e d(Sn1 e X2)) in Å. With
D
x (from 0.1880 Å for 1 to 0.0483 Å in the case
of 3, e.g. with increasing covalent radii of the X atom) the position
of the signal of the NH moiety in the 1H NMR spectra shifts to lower
frequencies (from 11.06 ppm for 1 to 10.14 ppm in the case of 3,
recorded in CDCl3, Diagram S2). Similar trend is found when the 1H
NMR chemical shift values of the NH moiety and NeH/X inter-
atomic distances in LCN(n-Bu)2SnX$HX (X ¼ Cl, Br and I) are
correlated (Diagram S3). With increasing covalent radii of the X
atom (e.g. with lengthening of the NeH/X bond, with softer acid
3.4. Raman spectroscopy
Raman scattering measurements were carried out using an
FT-spectrometer IFS-55 FRA 106 (Bruker); using the excitation line
1064 nm (Nd:YAG laser), with a Ge-detector cooled by liquid

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2483
nitrogen. A back-scattering geometry was used. Raman spectra
were measured at room temperature.
3.9. Reaction of LCN(n-Bu)2SnCl with an excess of HCl
CN(n-Bu)2SnCl (250 mg, 0.62 mmol) was dissolved in methanol
L
(15 mL) and aqueous HCl (35%, 547 L, 6.20 mmol) was added. The
reaction mixture was refluxed for 1 h and the second portion of HCl
(547 L, 6.20 mmol) was added again. The reflux continued for 1 h.
m
3.5. Synthesis
m
L
CN(n-Bu)2SnCl [11e], LCNPh2SnCl [11d], (LCN)2Sn(n-Bu)Cl [11e],
CN(n-Bu)SnCl2 [11c] and LCNPhSnCl2 [11b] were prepared accord-
Afterwards the volatiles were removed in vacuo and the residue
was extracted with CHCl3. The chloroform extract was dried with
Na2SO4 and filtered. The filtrate was reduced in vacuo giving 198 mg
of yellow oily product. Yield 67%. 1H NMR (CDCl3, 295 K, ppm):
10.23 (br, 1H, NH); 7.58 (m, 2H, LCN group); 7.41 (m, 3H, LCN group);
4.29 (d, 2H, NCH2, 3J(1H(NH), 1H(NCH2)) ¼ 5.1 Hz); 2.84 (d, 6H, N
(CH3)2, 3J(1H(NH), 1H(N(CH3)2)) ¼ 4.6 Hz); 1.93 (m, 4H, H(1)); 1.85
(m, 4H, H(2)); 1.40 (m, 4H, H(3)); 0.91 (t, 6H, H(4)). 119Sn NMR
(CDCl3, 295 K, ppm): ꢀ22.0. Elemental analysis (%): found: C, 42.2;
H, 7.1; N, 3.1. Calcd. for C17H32Cl3NSn (475.50): C, 42.90; H, 6.78; N,
2.95.
L
ing to published procedures. All solvents and both protic and Lewis
acids were obtained from commercial sources (SigmaeAldrich).
Diethyl ether was used as received. All reactions were carried out in
the air except for reactions of Lewis acids which were handled by
standard Schlenk techniques under an argon atmosphere. Single
crystals suitable for XRD analyses were obtained from corre-
sponding solutions of products by slow evaporation of the solvent.
Melting points are uncorrected.
3.6. Preparation of 1
3.10. Preparation of 4
Aqueous HCl (35%, 121
mL, 1.37 mmol) was added to a solution of
L
CN(n-Bu)2SnCl (500 mg, 1.24 mmol) in diethyl ether (10 mL). The
Aqueous HCl (35%, 88
mL, 0.99 mmol) was added to a solution of
reaction mixture was stirred overnight. Afterwards the volatiles
were removed in vacuo giving 530 mg of white crystalline product.
Yield 97%. M.p. 92e94 ꢁC. 1H NMR (CDCl3, 295 K, ppm): 11.06 (br,
L
CNPh2SnCl (400 mg, 0.90 mmol) in THF (20 mL). The reaction
mixture was stirred for 24 h. Formed precipitate was filtered off and
the filtrate was concentrated in vacuo giving 281 mg of white
crystalline product. Yield 65%. M.p. 148e150 ꢁC. 1H NMR (DMSO-d6,
1H, NH); 7.84 (d, 1H, H(60), J(1H(50), H(60)) ¼ 6.7 Hz, 3J(119Sn,
1H) ¼ 60.1 Hz); 7.44 (m, 1H, H(50)); 7.30 (m, 2H, H(40, 30)); 3.83 (d,
2H, NCH2, 3J(1H(NH), 1H(NCH2)) ¼ 5.4 Hz); 2.68 (d, 6H, N(CH3)2,
3J(1H(NH), 1H(N(CH3)2)) ¼ 4.8 Hz); 1.88 (m, 4H, H(1)); 1.78 (m, 4H,
H(2)); 1.46 (m, 4H, H(3)); 0.96 (t, 6H, H(4)). 119Sn NMR (CDCl3,
295 K, ppm): ꢀ105.1. Elemental analysis (%): found: C, 46.9; H, 6.8;
N, 3.4. Calcd. for C17H31Cl2NSn (439.04): C, 46.51; H, 7.12; N, 3.19.
3
1
295 K, ppm): 9.83 (br, 1H, NH); 8.28 (d, 4H, H(200), J(1H(300), 1H
3
(200)) ¼ 6.7 Hz, 3J(119Sn, 1H) ¼ 68.9 Hz); 7.63 (d, 1H, H(60), 3J(1H(50),
1H(60)) ¼ 7.3 Hz, 3J(119Sn, 1H) ¼ 56.2 Hz); 7.57 (m, 2H, H(400)); 7.46
(m, 5H, LCN and Ph group); 7.41 (m, 4H, LCN and Ph group); 4.34 (d,
2H, NCH2, 3J(1H(NH), 1H(NCH2)) ¼ 5.5 Hz); 2.41 (d, 6H, N(CH3)2,
3J(1H(NH), 1H(N(CH3)2)) ¼ 4.7 Hz). 119Sn NMR (DMSO-d6, 295 K,
ppm): ꢀ252.0. Elemental analysis (%): found: C, 52.5; H, 5.00;
N, 3.0. Calcd. for C21H23Cl2NSn (479.02): C, 52.66; H, 4.84; N, 2.92.
3.7. Preparation of 2
3.11. Preparation of 5
Aqueous HBr (46%, 774
mL, 6.6 mmol) was added to a solution of
L
CN(n-Bu)2SnCl (1.210 g, 3.00 mmol) in diethyl ether (15 mL). The
Aqueous HBr (46%, 145
mL,1.23 mmol) was added to a solution of
reaction mixture was stirred for 24 h. Afterwards the volatiles were
removed in vacuo and the crude product was crystallized from
acetonitrile giving 1.180 g of white crystalline product. Yield 81%.
M.p. 117e119 ꢁC. 1H NMR (CDCl3, 295 K, ppm): 10.44 (br, 1H, NH);
7.85 (d, 1H, H(60), 3J(1H(50), 1H(60)) ¼ 7.2 Hz, 3J(119Sn, 1H) ¼ 52.3 Hz);
7.44 (m, 1H, H(50)); 7.30 (m, 2H, H(40, 30)); 3.75 (d, 2H, NCH2, 3J(1H
(NH), 1H(NCH2)) ¼ 4.8 Hz); 2.64 (d, 6H, N(CH3)2, 3J(1H(NH), 1H(N
(CH3)2)) ¼ 4.8 Hz); 1.87 (m, 4H, H(1)); 1.81 (m, 4H, H(2)); 1.44 (m,
4H, H(3)); 0.95 (t, 6H, H(4)). 119Sn NMR (CDCl3, 295 K, ppm): ꢀ94.2.
Elemental analysis (%): found: C, 38.3; H, 6.1; N, 2.5. Calcd. for
C17H31Br2NSn (527.94): C, 38.68; H, 5.92; N, 2.65.
L
CNPh2SnCl (250 mg, 0.56 mmol) in THF (15 mL). The reaction
mixture was stirred overnight. After removing the volatiles in vacuo
the residue was washed with MeOH (2 ꢂ 5 mL) giving 140 mg of
white crystalline product. Yield 47%. M.p. 152e153 ꢁC. 1H NMR
(CDCl3, 295 K, ppm): 10.32 (br, 1H, NH); 8.22 (d, 4H, H(200), 3J(1H
(300), 1H(200)) ¼ 6.6 Hz, 3J(119Sn, 1H) ¼ 62.3 Hz); 7.77 (d, 1H, H(60), 3J
1
(1H(50), H(60)) ¼ 7.2 Hz, 3J(119Sn, 1H) ¼ 58.5 Hz); 7.67 (m, 2H, H
(400)); 7.43 (m, 5H, LCN and Ph group); 7.23 (m, 4H, LCN and Ph
group); 4.05 (d, 2H, NCH2, 3J(1H(NH), 1H(NCH2)) ¼ 5.1 Hz); 2.18 (d,
6H, N(CH3)2, 3J(1H(NH), 1H(N(CH3)2)) ¼ 4.2 Hz). 119Sn NMR (CDCl3,
295 K, ppm): ꢀ213.8. Elemental analysis (%): found: C, 44.2; H, 4.3;
N, 2.6. Calcd. for C21H23Br2NSn (567.92): C, 44.41; H, 4.08; N, 2.47.
3.8. Preparation of 3
3.12. Preparation of 6
Aqueous HI (57%, 739
mL, 5.60 mmol) was added to a solution of
L
CN(n-Bu)2SnCl (1.027 g, 2.55 mmol) in diethyl ether (10 mL). The
Aqueous HI (57%, 163
mL, 1.23 mmol) was added to a solution of
reaction mixture was stirred for 24 h. Afterwards the volatiles were
removed in vacuo, the residue was washed with MeOH (2 ꢂ 2 mL)
and the crude product was crystallized from acetonitrile giving
0.888 g of yellowish crystalline product. Yield 56%. M.p.101e103 ꢁC.
1H NMR (CDCl3, 295 K, ppm): 10.14 (br, 1H, NH); 7.67 (d, 1H, H(60),
3J(1H(50), 1H(60)) ¼ 7.3 Hz, 3J(119Sn, 1H) ¼ 60.0 Hz); 7.39 (m, 1H, H
(50)); 7.34 (m, 2H, H(40, 30)); 4.16 (d, 2H, NCH2, 3J(1H(NH), 1H
L
CNPh2SnCl (250 mg, 0.56 mmol) in THF (15 mL). The reaction
mixture was stirred for 24 h. After removing the solvent in vacuo
the residue was extracted with CHCl3 (2 ꢂ 15 mL). The extract was
filtered and the filtrate was concentrated in vacuo giving 190 mg of
yellowish crystalline product. Yield 51%. M.p. 125e127 ꢁC. 1H NMR
(CDCl3, 295 K, ppm): 10.47 (br, 1H, NH); 8.34 (d, 4H, H(200), 3J(1H
(300), 1H(200)) ¼ 7.8 Hz, 3J(119Sn, 1H) ¼ 69.0 Hz)); 7.79 (d, 1H, H(60),
3J(1H(50), 1H(60)) ¼ 7.6 Hz); 7.65 (m, LCN and Ph group); 7.57 (m, LCN
and Ph group); 4.55 (d, 2H, NCH2, 3J(1H(NH), 1H(NCH2)) ¼ 6.6 Hz);
2.75 (d, 6H, N(CH3)2, 3J(1H(NH), 1H(N(CH3)2)) ¼ 5.1 Hz). 119Sn NMR
(CDCl3, 295 K, ppm): ꢀ298.0. Elemental analysis (%): found: C, 38.5;
H, 4.0; N, 2.5. Calcd. for C21H23I2NSn (661.92): C, 38.1; H, 3.5; N, 2.1.
(NCH2))
¼
4.6 Hz); 2.75 (d, 6H, N(CH3)2, 3J(1H(NH), 1H(N
(CH3)2)) ¼ 4.0 Hz); 1.86 (m, 4H, H(1)); 1.70 (m, 4H, H(2)); 1.40 (m,
4H, H(3)); 0.90 (t, 6H, H(4)). 119Sn NMR (CDCl3, 295 K, ppm): ꢀ61.0.
Elemental analysis (%): found: C, 33.0; H, 5.3; N, 2.2. Calcd. for
C17H31I2NSn (621.94): C, 32.83; H, 5.02; N, 2.25.

ꢀ
2484
P. Svec et al. / Journal of Organometallic Chemistry 695 (2010) 2475e2485
3.13. Preparation of 7
ppm): ꢀ216.4. Elemental analysis (%): found: C, 44.8; H, 6.3; N, 4.5.
Calcd. for C22H36Cl4N2Sn (589.04): C, 44.86; H, 6.16; N, 4.76.
L
CN(n-Bu)2SnCl (403 mg, 1.00 mmol) was dissolved in diethyl
ether and aqueous HNO3 (65%, 346 L, 5.00 mmol) was added. The
m
3.17. Preparation of 11
reaction mixture was stirred overnight. Afterwards the volatiles
were removed in vacuo and the residue was extracted with chlo-
roform (15 mL). The chloroform phase was dried with Na2SO4 and
filtered. Finally the solvent was evaporated giving 365 mg of
yellowish oily product. The crude product was recrystallized from
benzene. Overall yield 69%. M.p. 84e85 ꢁC. 1H NMR (C6D6, 295 K,
ppm): 9.16 (br, 1H, NH); 7.15 (m, 3H, LCN group); 7.03 (m, 2H, LCN
group); 3.48 (d, 2H, NCH2, 3J(1H(NH), 1H(NCH2)) ¼ 5.4 Hz); 2.03 (d,
6H, N(CH3)2, 3J(1H(NH), 1H(N(CH3)2)) ¼ 5.0 Hz); 1.32 (m, 4H, H(1));
1.22 (m, 4H, H(2)); 0.91 (m, 4H, H(3)); 0.76 (t, 6H, H(4)). 119Sn NMR
(C6D6, 295 K, ppm): ꢀ401.6. Elemental analysis (%): found: C, 38.5;
H, 6.0; N, 8.1. Calcd. for C17H32ClN3Sn (528.60): C, 38.63; H, 6.10; N,
7.95.
Aqueous HCl (35%, 127
mL, 1.44 mmol) was added to a solution of
L
CN(n-Bu)SnCl2 (500 mg, 1.31 mmol) in diethyl ether (10 mL). The
reaction mixture was stirred overnight. Afterwards the volatiles
were removed in vacuo giving 504 mg of white crystalline product.
Yield 92%. Single crystals were obtained from THF solution via slow
evaporation of the solvent. M.p. 137e139 ꢁC. 1H NMR (CDCl3, 295 K,
ppm): 10.28 (br, 1H, NH); 7.61 (d, 1H, H(60), J(1H(50), 1H
3
(60)) ¼ 6.9 Hz, 3J(119Sn, 1H) ¼ 79.6 Hz); 7.46 (m, 2H, H(40, 30)); 7.18
(m, 1H, H(50)); 4.51 (d, 2H, NCH2, 3J(1H(NH), 1H(NCH2)) ¼ 5.5 Hz);
2.82 (d, 6H, N(CH3)2, 3J(1H(NH), 1H(N(CH3)2)) ¼ 4.7 Hz); 2.24 (t, 2H,
H(1)); 2.00 (m, 2H, H(2)); 1.53 (m, 2H, H(3)); 0.97 (t, 3H, H(4)). 119Sn
NMR (CDCl3, 295 K, ppm): ꢀ196.0. Elemental analysis (%): found: C,
37.1; H, 5.5; N, 3.4. Calcd. for C13H22Cl3NSn (417.38): C, 37.41; H,
5.31; N, 3.36.
3.14. Preparation of 8
L
CN(n-Bu)2SnCl (528 mg, 1.31 mmol) was dissolved in chloro-
form (15 mL) and trifluoroacetic acid (214 L, 2.88 mmol) was
3.18. Preparation of 12
m
added dropwise. The reaction mixture was stirred overnight. The
volatiles were then evaporated giving 748 mg of yellowish oily
product. Yield 96%. Single crystals were obtained from chloroform
solution via slow evaporation of the solvent. M.p. 99e103 ꢁC. 1H
NMR (CDCl3, 295 K, ppm): 10.66 (br, 1H, NH); 7.73 (d, 1H, H(60),
3J(1H(50), 1H(60)) ¼ 7.2 Hz, 3J(119Sn, 1H) ¼ 54.4 Hz); 7.47 (t,1H, H(50));
7.40 (m, 2H, H(40, 30)); 4.57 (br, 2H, NCH2); 2.87 (d, 6H, N(CH3)2, 3J
(1H(NH), 1H(N(CH3)2)) ¼ 4.6 Hz); 1.76 (m, 4H, H(1)); 1.66 (m, 4H, H
(2)); 1.45 (m, 4H, H(3)); 0.95 (t, 6H, H(4)). 13C NMR (CDCl3, 295 K,
selected signals, ppm): 162.1 (q, OOC, 2J(19F, 13C) ¼ 41.1 Hz); 115.9
(q, CF3, 1J(19F, 13C) ¼ 288.2 Hz). 19F NMR (CDCl3, 295 K, ppm): ꢀ74.7.
119Sn NMR (CDCl3, 295 K, ppm): ꢀ130.1. Elemental analysis (%): C,
42.9; H, 5.1; N, 2.2. Calcd. for C21H31F6NO4Sn (594.17): C, 42.45; H,
5.26; N, 2.36.
L
CNPhSnCl2 (501 mg, 1.25 mmol) was dissolved in THF/diethyl
ether mixture (1:1, 20 mL) and aqueous HCl (35%, 122 L,
m
1.38 mmol) was added. The reaction mixture was stirred overnight.
Afterwards the volatiles were removed in vacuo and the residue
was extracted with chloroform (2 ꢂ 20 mL). The extract was
reduced in vacuo giving 396 mg of white crystalline product. Yield
73%. M.p. 134e136 ꢁC. 1H NMR (THF-d8, 295 K, ppm): 10.15 (br, 1H,
NH); 8.36 (d, 2H, H(200), J(1H(300), H(200)) ¼ 6.9 Hz, 3J(119Sn,
1H) ¼ 92.1 Hz); 7.51 (d, 1H, H(60), 3J(1H(50), 1H(60)) ¼ 6.2 Hz, 3J(119Sn,
1H) ¼ 93.7 Hz); 7.44e7.29 (m, Ph and LCN groups); 4.60 (d, 2H,
NCH2, 3J(1H(NH), 1H(NCH2)) ¼ 6.1 Hz); 2.85 (d, 6H, N(CH3)2, 3J(1H
(NH), 1H(N(CH3)2)) ¼ 5.2 Hz). 119Sn NMR (THF-d8, 295 K, ppm):
ꢀ262.7. Elemental analysis (%): found: C, 41.0; H, 4.3; N, 3.4. Calcd.
for C15H18Cl3NSn (437.37): C, 41.19; H, 4.15; N, 3.20.
3
1
3.15. Preparation of 9
3.19. Reaction of LCN(n-Bu)SnF2 with triphosgene
Aqueous HCl (35%, 92
m
L, 1.04 mmol) was added to a solution of
L
CN(n-Bu)2SnF (313 mg, 0.81 mmol) was dissolved in toluene
(LCN)2(n-Bu)SnCl (500 mg, 1.04 mmol) in diethyl ether (15 mL). The
reaction mixture was stirred overnight. Afterwards the volatiles
were removed in vacuo and the crude oily product was crystallized
from chloroform giving 408 mg of yellowish crystals. Yield 76%.
M.p. 69e72 ꢁC. 1H NMR (CDCl3, 295 K, ppm): 11.80 (br,1H, NH); 8.22
and 8.16 (br, 2H, two non-equivalent H(60)); 7.33 (m, 4H, LCN
groups); 7.10 (m, 2H, LCN groups); 4.03 (br d, 2H, þNCH2,
J ¼ 147.1 Hz); 3.39 (br d, 2H, NCH2, J ¼ 94.4 Hz); 2.53 (br, 6H, þN
(CH3)2); 2.21 (m, 2H, H(1)); 1.64 (br, 8H, (N(CH3)2 and H(2)); 1.31
(m, 2H, H(3)); 0.80 (t, 3H, H(4)). 119Sn NMR (CDCl3, 295 K, ppm):
ꢀ125.0. Elemental analysis (%): found: C, 51.0; H, 6.6; N, 5.5. Calcd.
for C22H34Cl2N2Sn (516.12): C, 51.20; H, 6.64; N, 5.43.
(10 mL) and triphosgene (40 mg, 0.13 mmol) was added. The
reaction mixture was stirred for 1 h. Afterwards the reaction
mixture was concentrated in vacuo. Single crystals of 13 were
obtained from the concentrated reaction mixture which was left for
one week in a glass flask. Yield 54 mg (14%). For NMR spectra see
discussion above. Raman spectroscopy (cmꢀ1): 255, 338, 509, 602,
841, 965, 1060, 1173, 1464, 1588, 2132, 2974e2800, 3056. Elemental
analysis (%): found: C, 43.2; H, 5.9; N, 2.5. Calcd. for
C34H61Sn2N2Cl3F6 (956.62): C, 42.7; H, 6.6; N, 2.9.
3.20. Reaction of LCN(n-Bu)2SnCl with SnCl4 (1:1 ratio)
L
CN(n-Bu)2SnCl (258 mg, 0.64 mmol) was dissolved in toluene
3.16. Preparation of 10
and SnCl4 (168 mg, 0.64 mmol) was added in one portion at room
temperature. The reaction mixture was stirred overnight. After-
wards the solvent was evaporated in vacuo. According to 1H and
119Sn NMR spectroscopy the reaction residue consisted of 1:1
mixture of (n-Bu)2SnCl2 [16] and LCNSnCl3 [20].
Aqueous HCl (35%, 386 mL, 4.37 mmol) was added to a solution of
(LCN)2(n-Bu)SnCl (500 mg, 2.08 mmol) in diethyl ether (15 mL). The
reaction mixture was stirred overnight. Afterwards the volatiles
were removed in vacuo giving 530 mg of white crystalline product.
Yield 92%. M.p. 160e161 ꢁC. 1H NMR (DMSO-d6, 295 K, ppm): 11.90
3.21. Reaction of LCN(n-Bu)2SnCl with SnCl4 (4:1 ratio)
(br, 1H, NH); 7.84 (d, 1H, H(60), J(1H(50), 1H(60)) ¼ 7.3 Hz, 3J(119Sn,
3
1H) ¼ 77.3 Hz); 7.70 (d, 1H, H(30)); 7.41 (m, 2H, H(40, 50)); 4.51 (d, 2H,
NCH2, 3J(1H(NH), 1H(NCH2)) ¼ 5.2 Hz); 2.72 (d, 6H, N(CH3)2, 3J(1H
(NH), 1H(N(CH3)2)) ¼ 4.6 Hz); 1.89 (br, 2H, H(1)); 1.75 (br, 2H, H(2));
1.44 (m, 2H, H(3)); 0.93 (t, 3H, H(4)). 119Sn NMR (DMSO-d6, 295 K,
L
CN(n-Bu)2SnCl (250 mg, 0.62 mmol) was dissolved in toluene
and SnCl4 (40 mg, 0.16 mmol) was added in one portion at room
temperature. The reaction mixture was stirred overnight. After-
wards the solvent was evaporated in vacuo. According to 1H and

ꢀ
P. Svec et al. / Journal of Organometallic Chemistry 695 (2010) 2475e2485
2485
119Sn NMR spectroscopy the reaction residue consisted of ca. 1:1:1
mixture of LCN(n-Bu)2SnCl [11e], (n-Bu)2SnCl2 [16] and LCNSnCl3
[20]. Essentially the same results were obtained when the reaction
mixture was refluxed for 4 h in toluene.
from The Director, CCDC, 12 Union Road, Cambridge CB2 1EY, UK
(fax: þ44-1223-336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
Supporting information related to this article can be found in
the online version, at doi:10.1016/j.jorganchem.2010.08.006
3.22. Reaction of LCN(n-Bu)2SnCl with SnBr4 (2:1 ratio)
References
L
CN(n-Bu)2SnCl (203 mg, 0.50 mmol) was dissolved in toluene
and SnBr4 (111 mg, 0.25 mmol) was added in one portion at room
temperature. The reaction mixture was stirred overnight. After-
wards the solvent was evaporated in vacuo. According to 1H and
119Sn NMR spectroscopy the reaction residue consisted of mixture
of LCN(n-Bu)2SnBr as the major product [24], (n-Bu)2Sn(Cl)Br [16]
and LCNSnBr3 [11b] as minor products.
[1] (a) A.G. Davies, Organotin Chemistry. Wiley-VCH, Weinheim, 2004, (Chapter 5),
pp. 67e81, (Chapter 11), pp. 166e178;
(b) F.A.G. Mercier, Synthesis, Characterization and Catalytic Activity of Dia-
lkyltin Compounds Grafted onto Insoluble Cross-linked Polystyrene, Ph.D.
thesis, Vrije Universiteit Brussel, 2002.
[2] K.A. Kocheshkov, Ber. Deutsch. Chem. Gessel 62 (1926) 996.
[3] (a) J.C. Martins, F.A.G. Mercier, A. Vandervelden, M. Biesemans, J.-M. Wieruszeski,
E. Humpfer, R. Willem, G. Lippens, Chem. Eur. J. 8 (2002) 3431;
(b) V. Pinoie, K. Poelmans, H.E. Miltner, I. Verbruggen, M. Biesemans, G. Van
Assche, B. Van Mele, J.C. Martins, R. Willem, Organometallics 26 (2007)
6718e6725.
[4] (a) K. Poelmans, V. Pinoie, I. Verbruggen, M. Biesemans, G. Van Assche,
G. Deshayes, P. Degée, P. Dubois, R. Willem, Appl. Organomet. Chem. 21 (2007)
504;
3.23. Reaction of LCNPh2SnCl with SnCl4 (1:1 ratio)
L
CNPh2SnCl (232 mg, 0.52 mmol) was dissolved in toluene and
SnCl4 (136 mg, 0.52 mmol) was added in one portion at room
temperature. The reaction mixture was stirred overnight. After-
wards the solvent was evaporated in vacuo. According to 1H and
119Sn NMR spectroscopy the reaction residue consisted of 1:1
mixture of Ph2SnCl2 [30] and LCNSnCl3 [20].
(b) K. Poelmans, V. Pinoie, I. Verbruggen, M. Biesemans, G. Deshayes,
E. Duquesne, C. Delcourt, P. Degée, H.E. Miltner, P. Dubois, R. Willem,
Organometallics 27 (2008) 1841.
ꢀ
ꢀ
ꢀ
ꢁꢀ ꢀ
ꢀ
[5] P. Novák, Z. Padelková, I. Císarová, L. Kolárová, A. Ruzicka, J. Holecek, Appl.
Organomet. Chem. 20 (2006) 226.
[6] R.A. Varga, C. Silvestru, Acta Crystallogr. Sect. C: Cryst. Struct. Commun. 63
(2007) m48.
[7] S.H.L. Thoonen, H. van Hoek, E. de Wolf, M. Lutz, A.L. Spek, B.-J. Deelman,
G. van Koten, J. Organomet. Chem. 691 (2006) 1544.
3.24. Reaction of LCNPh2SnCl with SnCl4 (2:1 ratio)
CNPh2SnCl (248 mg, 0.56 mmol) was dissolved in toluene and
ꢀ
ꢀ
ꢁꢀ ꢀ
ꢀ
[8] P. Novák, I. Císarová, L. Kolárova, A. Ruzicka, J. Holecek, J. Organomet. Chem.
692 (2007) 4287.
L
SnCl4 (73 mg, 0.28 mmol) was added in one portion at room
temperature. The reaction mixture was stirred overnight. After-
wards the solvent was evaporated in vacuo. According to 1H and
119Sn NMR spectroscopy the reaction residue consisted of mixture
of LCNPh2SnCl (w35%) [11d], Ph2SnCl2 (w20%) [30], Ph3SnCl (w10%)
[30] and LCNSnCl3 (w35%) [20].
ꢁꢀ ꢀ
ꢀ
ꢀ
[9] R. Jambor, A. Ruzicka, J. Brus, I. Císarová, J. Holecek, Inorg. Chem. Commun. 4
(2001) 257.
ꢀ
ꢀ
ꢀ
[10] Z. Padelková, T. Weidlich, L. Kolárová, A. Eisner, I. Císarová, T.A. Zevaco,
A. Ruzicka, J. Organomet. Chem. 692 (2007) 5633.
[11] (a) Z. Padelková, I. Císarová, A. Ruzicka, Acta Crystallogr. E61 (2005)
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ꢀ
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M2691eM2693;
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ꢀ
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(b) P. Novák, Z. Padelková, L. Kolárová, I. Císarová, A. Ruzicka, J. Holecek, Appl.
Organomet. Chem. 19 (2005) 1101;
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ꢀ
ꢀ
ꢁꢀ ꢀ
ꢀ
(c) P. Svec, Z. Padelková, I. Císarová, A. Ruzicka, J. Holecek, Main Group Met.
Chem. 31 (2008) 305;
3.25. Reaction of LCNPh2SnCl with SnCl4 (3:1 ratio)
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ꢀ
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(d) A. Ruzicka, R. Jambor, J. Brus, I. Císarová, J. Holecek, Inorg. Chim. Acta. 323
(2001) 163;
L
CNPh2SnCl (254 mg, 0.57 mmol) was dissolved in toluene and
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(e) A. Ruzicka, V. Pejchal, J. Holecek, A. Lycka, K. Jacob, Collect. Czech. Chem.
Commun. 63 (1998) 977.
SnCl4 (50 mg, 0.19 mmol) was added in one portion at room
temperature. The reaction mixture was stirred overnight. After-
wards the solvent was evaporated in vacuo. According to 1H and
119Sn NMR spectroscopy the reaction residue consisted of mixture
of LCNPh2SnCl (w20%) [11d], Ph2SnCl2 (w30%) [30], Ph3SnCl (w10%)
[30] and LCNSnCl3 (w40%) [20].
[12] H.A. Bent, J. Chem. Phys. 33 (1959) 1258.
[13] B. Cordero, V. Gómez, A.E. Platero-Prats, M. Revés, J. Echeverría, E. Cremades,
S. Alvarez, Dalton Trans. (2008) 2832.
[14] V. Pinoie, Design and application of efficient and recyclable grafted organotin
catalysts for transesterifications, Ph.D. thesis, Vrije Universiteit Brussel, 2009.
[15] D. Dakternieks, H. Zhu, Organometallics 11 (1992) 3820.
ꢀ
ꢀ
ꢀ
[16] J. Holecek, M. Nádvorník, K. Handlír, A. Lycka, J. Organomet. Chem. 315 (1986) 299.
[17] A.W. Addison, T.N. Rao, J. Reedijk, J. van Rijn, G.C. Verschoor, J. Chem. Soc.
Dalton Trans. (1984) 1349.
3.26. Reaction of LCNPh2SnCl with SnCl4 (1:3 ratio)
[18] (a) A. Bondi, J. Phys. Chem. 3 (1964) 441;
L
CNPh2SnCl (239 mg, 0.54 mmol) was dissolved in toluene and
(b) L. Pauling, The Nature of the Chemical Bond. Cornell University Press,
Ithaca, 1942, pp. 192.
SnCl4 (422 mg, 1.62 mmol) was added in one portion at room
temperature. The reaction mixture was stirred overnight. After-
wards the solvent was evaporated in vacuo. According to 1H and
119Sn NMR spectroscopy the reaction residue consisted of mixture
of Ph2SnCl2 (w30%) [30], PhSnCl3 (w30%) [30] and LCNSnCl3
(w40%) [20].
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[19] P. Svec, Z. Padelková, T. Weidlich, L. Dusek, L. Plasseraud, A. Ruzicka,
J. Organomet. Chem., in preparation.
[20] R.A. Varga, C. Silvestru, C. Deleanu, Appl. Organomet. Chem. 19 (2005) 153.
ꢀ
ꢀ
ꢁꢀ ꢀ
[21] P. Svec, A. Eisner, L. Kolárová, T. Weidlich, V. Pejchal, A. Ruzicka, Tetrahedron
Lett. 49 (2008) 6320.
[22] (a) A. Ouasri, A. Rhandour, M.-C. Dhamelincourt, P. Dhamelincourt, A. Mazzah,
J. Raman Spectrosc. 33 (2002) 726;
(b) A. Ouasri, A. Rhandour, M.-C. Dhamelincourt, P. Dhamelincourt, A. Mazzah,
Spectrochimica Acta Part A 59 (2003) 357.
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Acknowledgements
ꢀ
ꢀ
ꢀ
[23] J. Turek, Z. Padelková, Z. Cernosek, M. Erben, A. Lycka, M.S. Nechaev,
ꢀ
ꢁꢀ ꢀ
I. Císarová, A. Ruzicka, J. Organomet. Chem. 694 (2009) 3000.
ꢀ
ꢁꢀ ꢀ
ꢀ
[24] M. Biesemans, J.C. Martins, R. Willem, A. Lycka, A. Ruzicka, J. Holecek, Magn.
Reson. Chem. 40 (2002) 65.
[25] C.J. Pouchert, J. Behnke, The Aldrich Library of 13C and 1H FT NMR Spectra.
Aldrich Chemical Company, Inc., Milwaukee, USA, 1993.
[26] Z. Otwinowski, W. Minor, Methods Enzymol. 276 (1997) 307.
[27] P. Coppens, in: F.R. Ahmed, S.R. Hall, C.P. Huber (Eds.), Crystallographic
Computing, Munksgaard, Copenhagen, 1970, pp. 255e270.
[28] A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi, J. Appl, Crystallogr 26
(1993) 343.
[29] G.M. Sheldrick, SHELXL-97. University of Göttingen, Göttingen, 1997.
[30] M.E. Wood, in: M.G. Moloney (Ed.), Science of Synthesis, vol. 5, Thieme
Chemistry, Stuttgart, Germany, 2002, pp. 315e353.
The authors would like to thank the Science Foundation of the
Czech Republic (P207/10/0215) and the Ministry of Education of the
Czech Republic (VZ 0021627501) for financial support.
Appendix A. Supporting information
Crystallographic data for structural analysis have been depos-
ited with the Cambridge Crystallographic Data Centre (789986–
789995). Copies of this information may be obtained free of charge