Novel trialkanolamine derivatives of tin of the type [N(CH 2CMe2O)2(CH2)nOSnOR] m (m = 1, 2; N = 2, 3; R = t -Bu, 2,6-Me2C 6H3) and related tri- and pentanu

Article abstract of DOI:10.1021/ic302042n

The syntheses of the novel alkanolamine N(CH₂CMe ₂OH)₂(CH₂CH₂CH₂OH) (2), the novel aminotrialkoxides of tin of the type [N(CH₂CMe ₂O)₂(CH₂)_n

Full text of DOI:10.1021/ic302042n

Article
pubs.acs.org/IC
Novel Trialkanolamine Derivatives of Tin of the Type
[N(CH2CMe2O)2(CH2)nOSnOR]m (m = 1, 2; n = 2, 3; R = t‑Bu, 2,6-
Me2C6H3) and Related Tri- and Pentanuclear Tin(IV) Oxoclusters.
Syntheses and Molecular Structures
Thomas Zoller and Klaus Jurkschat*
̈
Lehrstuhl fur Anorganische Chemie II, Technischen Universitat Dortmund, D-44221 Dortmund, Germany
̈
̈
S
* Supporting Information
ABSTRACT: The syntheses of the novel alkanolamine N-
(CH2CMe2OH)2(CH2CH2CH2OH) (2), the novel amino-
t r i a l k o x i d e s o f t i n o f t h e t y p e [ N -
(CH2CMe2O)2(CH2)nOSnOR]m (3: m = 1, n = 2, R = t-Bu;
4: m = 2, n = 3, R = t-Bu; 5: m = n = 2, R = 2,6-Me2C6H3; 6: m
= 2, n = 3, R = 2,6-Me2C6H3) and the related trinuclear tin
o x o c l u s t e r s [ ( L S n O S n L ) ( L S n O R ) ] [ L
= N -
(CH2CMe2O)2(CH2CH2O), 7: R = t-Bu; 8: R = 2,6-
Me2C6H3] and the pentanuclear tin oxocluster [LSnOSn-
(OH)2OSnL·2LSnOH], [9, L = N(CH2CMe2O)2(CH2CH2O)] are reported. The compounds are characterized by elemental
analyses, multinuclear (1H, 13C, 119Sn, 1H-1H cosy, 1H-13C HSQC) NMR spectroscopy, electrospray ionization mass
spectrometry, and single crystal X-ray diffraction analyses (3, 4·C7H8, 5, 7, 8·0.5C7H8, 9·6H2O).
C6H4OMe18) are, however, monomeric both in solution and
in the solid state.
Stannatranes without any metal−carbon bond are less
studied19−24a and only few solid state structures as determined
by single crystal X-ray diffraction analysis have been described
so far (Scheme 1).19,23
INTRODUCTION
■
Tin alkoxides find application in sol−gel chemistry for the
manufacturing of tin dioxide thin films and related materials.
These materials can be used as transparent conductors in solar
cells, screens, and gas detection devices.1−7 Furthermore, we
found that alkanolamine derivatives of tin are excellent delayed
action catalysts for the formation of polyurethanes.8,9 These tin
aminoalkoxides of the types (R2NCH2CH2O)2SnX2 (A),
RN(CH2CH2O)2SnX2 (B), or N(CH2CH2O)3SnX (C) (R =
alkyl, aryl; X = alkoxide, alkanoate, halogen, hydroxide) are
characterized by a kinetically labile intramolecular N→Sn
coordination which is likely to be responsible for the delayed
action activity. The so-called dissociation-inversion mechanism
was analyzed in detail for the organically substituted
representatives (X = t-Bu).10−13 There is considerable interest
in inorganic, nontoxic tin compounds which might replace the
highly toxic, state of the art mercury catalysts, such as
p h e n y l m e r c u r y n e o d e c a n o a t e , P h H g O C ( O ) -
CH2CH2CH2CH2CH2CMe3.14
Compounds of type C are called stannatranes, and the
chemistry of the organotin derivatives N(CH2CH2O)3SnR (R
= alkyl, aryl) has been extensively studied in the past decades.15
Among these, the methylstannatrane, as its aqua solvate
[N(CH2CH2O)3SnMe]3·6H2O,16 is unique as it is a trimer
that is formed by intermolecular O→Sn interactions. The
trimerization is the result of insufficient steric protection of the
highly Lewis-acidic tin atom by the methyl substituent and the
triethanolamine framework. The t-butyl- and o-anisyl-substi-
tuted derivatives N(CH2CH2O)3SnR (R = t-Bu,17 o-
Scheme 1. Stannatranes Lacking Sn−C Bonds
Recently we have reported the syntheses and structures in
solution and in the solid state of the stannatranes N-
(CH2CMe2O)3SnX (X = Ot-Bu, Oi-Pr, 2,6-Me2C6H3O, p-t-
BuC6H4O, p-NO2C6H4O, p-FC6H4O, p-PPh2C6H4O, p-
MeC6H4S, o-NH2C6H4O, OCPh2CH2NMe2, Ph2P(S)S, p-t-
BuC6H4C(O)O, p-N[(CH2CMe2O)3SnOSiMe2]2C6H4, halo-
gen) (Scheme 1).23 Although the tin atoms in these
compounds are highly Lewis-acidic and prone to extend their
coordination number beyond five, they are monomeric with
trigonal-bipyramidally configurated metal atoms. Again, this is
the result of steric protection as induced by the methyl-
substitution at the carbinol carbon atoms (OC) of the atrane
Received: September 20, 2012
Published: January 31, 2013
© 2013 American Chemical Society
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framework. On successive replacement of these methyl
substituents by hydrogen atoms, control of the degree of
association via intermolecular O→Sn coordination should be
possible. Such strategy proved to be true in case of related
titanatranes.24b
The compounds 3−6 are crystalline, colorless solids that are
well soluble in dichloromethane, acetone, hot toluene, or
benzene. The t-butoxido-substituted derivatives 3 and 4 are
sensitive toward moisture.
The molecular structures of compounds 3, 4, as its toluene
solvate 4·C7H8, and 5 as determined by single crystal X-ray
diffraction analysis are shown in Figures 1, 2, and 3,
respectively. Selected interatomic distances and angles are
given in the figure captions. The unit cell of 3 contains two
crystallographic independent molecules A and B whose
interatomic distances and angles differ only slightly. Con-
sequently, only those of molecule A are discussed. Those of
molecule B are given in the Supporting Information, Figure S1.
The molecular structure of the t-butoxido-substituted
stannatrane 3 resembles those of the parent halogenido- and
aryloxido-substituted stannatranes N(CH2CMe2O)3SnX (X =
Cl, Br, I, OAr; Ar = p-t-BuC6H4, p-FC6H4, p-NO2C6H4, p-
Ph2PC6H4, 2,6-Me2C6H3).23 It is monomeric with the shortest
intermolecular Sn···O distance being 5.670(2) Å
(Sn(1)···O(103)). The Sn(1) atom is five-coordinate by one
nitrogen and four oxygen atoms and shows a distorted trigonal
bipyramidal configuration (ΔΣ(ϑ)34b = 56.2°) with N(1) and
O(4) occupying the axial and O(1), O(2), and O(3) occupying
the equatorial positions. The Sn(1)−N(1) distance of 2.275(2)
Å (molecule B: Sn(2)−N(2) 2.306(2) Å) is comparable with
the corresponding distances in the stannatranes mentioned
above.23 Interestingly, the Sn(1)−O(4) distance of 1.949(2) Å
(molecule B: Sn(2)−O(104) 1.949(2) Å) is shorter than the
distances to the equatorially bound oxygen atoms ranging
between 1.965(2) (Sn(1)−O(1)) and 1.985(2) Å (Sn(1)−
O(3)). One possible explanation is that this axial Sn(1)−O(4)
bond exhibits high ionic character and that the expected
lengthening as induced by the N→Sn coordination is more
than compensated for by electrostatic attraction.
In contrast to a great variety of organotin(IV) oxoclus-
ters,25−29 related clusters that lack any Sn−C bonds are scarce
and to the best of our knowledge, only the five crystallo-
graphically characterized examples Sn3O(Oi-Bu)10(HOi-Bu)2,30
[SnO(acac)2]3,31 Sn4O2(OEt)10(acac)2,1 [SnO(Ot-Bu)-
33
(OAc)]6,32 and Sn12O8(OH)4(OEt)28(HOEt)4 have been
reported so far. One reason for this might be that the hydrolysis
of purely inorganic tin alkoxides is very fast with the
consequence that oligomeric intermediates are difficult to
isolate.30 Chelating ligands with coordinating donor groups
such as aminoalkoxides should be suitable to stabilize such
oligomeric intermediates. Again, this was shown to be the case
for related titanatranes.24c,d
In context with what is stated above, we here report the novel
alkanolamine N(CH2CMe2OH)2(CH2CH2CH2OH), novel
i n o r g a n i c s t a n n a t r a n e s o f t h e t y p e [ N -
(CH2CMe2O)2(CH2)nOSnOR]m (m = 1, 2; n = 2, 3; R = t-
Bu, 2,6-Me2C6H3) as well as, by controlled hydrolysis of the
latter compounds, novel tri- and pentanuclear tin oxoclusters.
RESULTS AND DISCUSSION
■
The aminoalcohols bis(2-methyl-2-hydroxypropyl)(2-
hydroxyethyl)amine, N(CH2CMe2OH)2(CH2CH2OH) (1),34a
and bis(2-methyl-2-hydroxypropyl)(3-hydroxypropyl)amine,
N(CH2CMe2OH)2(CH2CH2CH2OH) (2), were prepared by
the reaction of 2-aminoethanol respectively 3-aminopropan-1-
ol with two equivalents of 1,1-dimethyloxirane (Scheme 2).
Scheme 2. Synthesis of Aminoalcohols 1 and 2
In contrast to the monomeric stannatranes of the type
N(CH2CMe2O)3SnX (X = OR, SR, halogen),23 the com-
pounds 4·C7H8 and 5 form dimers via intermolecular O→Sn
coordination to give four-membered planar Sn2O2 rings with
intracyclic Sn(1)−O(3)/Sn(1)−O(3A) distances of 2.046(2)/
2.232(2) Å (4·C7H8) and 2.059(2)/2.204(1) Å (5),
respectively. These μ2-O−Sn distances are comparable with
those of dimeric tin(II) aminoalkoxides [MeN-
(CH2CR2O)2Sn]2 [R = Me:35 2.140(2)/2.259(2) Å,
2.134(2)/2.244(2) Å; R = H:36 (2.176(9)/2.200(9) Å] and
with those of the tin(IV) compounds [Sn(Oi-Pr)4(HOi-
Compound 2 is a colorless oil, that crystallizes upon standing
at room temperature for several days. It is well soluble in
common organic solvents such as diethylether, tetrahydrofuran,
chloroform, dichloromethane, and toluene. Its molecular
structure including a graph set analysis of the hydrogen
bonding pattern will be published elsewhere.
The reaction of tin tetra-t-butoxide, Sn(Ot-Bu)4, with the
unsymmetrically substituted aminotrialcohols 1 and 2 gave the
novel 1-alkoxido-stannatranes 3 and 4, respectively (Scheme 3).
The acid−base type reactions of the t-butoxido-substituted
stannatranes 3 and 4 with 2,6-dimethylphenol provided the
corresponding aryloxido-substituted stannatranes 5 and 6,
respectively (Scheme 4).
37
30
33
Pr)2]2 (2.080(4)/2.091(4) Å), Sn3O(Oi-Bu)10(HOi-Bu)2
[2.096(3)/2.129(4) Å] and Sn12O8(OH)4(OEt)28(HOEt)4
[1.93(1)/2.13(1)]. To the best of our knowledge the
compounds 4·C7H8 and 5 are the first examples of crystallo-
graphically established dimeric stannatranes.
As result of the dimerization and the intramolecular N→Sn
coordination the tin atoms each show a distorted octahedral
configuration. The distortion from the ideal geometry is
Scheme 3. Synthesis of Compounds 3 and 4
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Scheme 4. Synthesis of Compounds 5 and 6
Figure 2. Molecular structure of compound 4·C7H8 (ORTEP
presentation at 30% probability of the depicted atoms and atom
numbering scheme). The asymmetric unit contains a half toluene
molecule which is omitted. Selected interatomic distances [Å] and
angles [deg]: Sn(1)−O(1) 1.979(2), Sn(1)−O(2) 2.002(2), Sn(1)−
O(3) 2.046(2), Sn(1)−O(4) 1.971(2), Sn(1)−O(3A) 2.232(2),
Sn(1)−N(1) 2.390(2); O(1)−Sn(1)−O(3) 138.78(7), O(2)−
Sn(1)−O(3A) 163.81(7), N(1)−Sn(1)−O(4) 167.23(7), Sn(1)−
O(3)−Sn(1A) 113.21(8), O(3)−Sn(1)−O(3A) 66.79(8).
Figure 1. Molecular structure of compound 3 (molecule A, ORTEP
presentation at 30% probability of the depicted atoms and atom
numbering scheme). Selected interatomic distances [Å] and angles
[deg]: Sn(1)−O(1) 1.965(2), Sn(1)−O(2) 1.976(2), Sn(1)−O(3)
1.985(2), Sn(1)−O(4) 1.949(2), Sn(1)−N(1) 2.275(2); O(1)−
Sn(1)−O(2) 119.18(7), O(1)−Sn(1)−O(3) 112.78(8), O(1)−
Sn(1)−O(4) 98.79(7), O(1)−Sn(1)−N(1) 81.08(8), O(2)−Sn(1)−
O(3) 120.85(8), O(2)−Sn(1)−O(4) 102.86(7), O(2)−Sn(1)−N(1)
80.67(8), O(3)−Sn(1)−O(4) 94.95(7), O(3)−Sn(1)−N(1)
81.37(8), O(4)−Sn(1)−N(1) 175.90(8), Sn(1)−O(4)−C(41)
124.6(2). The data for molecule B are rather similar and are given
in the Supporting Information, Figure S1.
manifested by the strong deviation of the trans-angles O(1)−
Sn(1)−O(3) [138.78(7)/126.67(6) Å], O(2)−Sn(1)−O(3A)
[163.81(7)/151.19(6) Å] and N(1)−Sn(1)−O(4) [167.23(7)/
158.50(6) Å] (4·C7H8/5) from 180°. The tin atoms are
displayed from the plane E(Oatrane) defined by the oxygen
atoms O(1)−O(3) by 0.3663(2) Å (4·C7H8) and 0.4663(1) Å
(5), respectively, in direction to the exocyclic ligand. The N−
Sn distances are 2.390(2) Å (4·C7H8) and 2.401(2) Å (5)
being among the longest N−Sn distances for stannatranes. The
N−Sn distances of comparable stannatranes of the type
N(CH2CMe2O)3SnX (X = OR, SR, halogen) (2.232(2)−
2.295(3) Å)23 or monoorgano-stannatranes of the type
[N(CH2CH2O)3SnR]n (R = Me, n = 3, d(N−Sn) = 2.28(1)
Å;16 R = t-Bu, n = 1, d(N−Sn) = 2.324 Å;17 R = C6H4-o-OMe,
n = 1, d(N−Sn) = 2.323(7) Å18) are considerable shorter while
the only longer N−Sn distance of 2.422(4) Å was found for
N(CH2CH2O)3SnOs(η2-S2CNMe2)(CO)(PPh3)2.19
Figure 3. Molecular structure of compound 5 (ORTEP presentation
at 30% probability of the depicted atoms and atom numbering
scheme). Selected interatomic distances [Å] and angles [deg]: Sn(1)−
O(1) 1.978(2), Sn(1)−O(2) 1.993(2), Sn(1)−O(3) 2.059(2),
Sn(1)−O(4) 2.024(1), Sn(1)−O(3A) 2.204(1), Sn(1)−N(1)
2.401(2); O(1)−Sn(1)−O(3) 126.67(6), O(2)−Sn(1)−O(3A)
151.19(6), N(1)−Sn(1)−O(4) 158.50(6), Sn(1)−O(3)−Sn(1A)
112.31(7), C(41)−Sn(1)−O(4) 122.26(1).
The five-membered atrane rings adopt uniform envelope
conformations and make the molecules chiral in terms of Δ and
Λ stereochemistry.23 The six-membered atrane ring in
compound 4·C7H8 adopts a twist-boat conformation. Given
the dimerization the formation of two pairs of enantiomers for
both 4·C7H8 and 5 is possible (Δ,Δ; Λ,Λ/Δ,Λ; Λ,Δ). In the
unit cells of the single crystals actually measured the
stereoisomers Δ,Λ-4 and Δ,Λ-5 are observed.
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The 119Sn NMR spectrum of 3 in C6D6 shows a sharp
resonance at δ −326 (3) and a signal of low intensity at δ −621
(2J(119Sn-117Sn) = 217 Hz) that is assigned to the trinuclear
partial hydrolysis product [(LSn-μ3-OSnL)(LSn-μ3-O-t-Bu)] [L
= N(CH2CMe2O)2(CH2CH2O)] (see also discussion of the
119Sn solution NMR spectrum of 7 below). The strong high
field chemical shift indicates higher coordination numbers at
the tin atoms. Successive addition of water to the NMR sample
causes the resonance at δ −621 to increase and the resonance
assigned to compound 3 to decrease and to finally completely
Scheme 5. Synthesis of Compounds 7 and 9
2
disappear. The absence of J(119Sn-O117Sn) satellites for the
resonance at δ −326 indicates compound 3, as in the solid
state, to be monomeric in solution as well.
The 119Sn NMR spectrum of compound 5 in CD2Cl2 exhibits
a single resonance at δ −335 that lacks 2J(119Sn-O117Sn)
satellites. In agreement with the chemical shift observed for
compound 3, it is assigned to the monomeric structure. A
monomer−dimer equilibrium that is fast on the 119Sn NMR
time scale and that lies on the monomer site cannot be ruled
out, however. This was not investigated further.
The 119Sn NMR spectra in CD2Cl2 of compounds 4 and 6
that contain an additional methylene group in the amino-
alkoxide framework show resonances at δ −400 (δ −395, T =
223 K) (4) respectively at δ −417 (6). In case of compound 6
there is an additional signal of low intensity (8%) at δ −431
that is not assigned. The significant highfield shifts as compared
to compounds 3 and 5 indicate higher coordination numbers at
the tin atoms by dimerization via intermolecular (CH2)O→Sn
interactions. This is confirmed by the 1H and 13C NMR spectra
showing strong downfield shifts of the CH2O and CH2O
Scheme 6. Synthesis of Compound 8
1
resonances for compounds 4 (δ H 4.28, δ 13C 68.5) and 6 (δ
1
1H 4.31, δ 13C 68.8) as compared with 3 (δ H 3.85, δ 13C
58.4) and 5 (δ 1H 3.89, δ 13C 58.7), respectively. The
assignment of the resonances was supported by 1H-13C HSQC
NMR experiments.
The partial hydrolysis of the stannatranes 3 and 5 gave the
novel tin oxoclusters 7 and 8, respectively as colorless
crystalline materials that show good solubility in dichloro-
methane and chloroform (Schemes 5, 6).
The molecular structures of compounds 7 and 8, as its
toluene solvate 8·0.5C7H8, as determined by single crystal X-ray
diffraction analysis, are shown in Figures 4 and 5, respectively.
Selected interatomic distances and angles are summarized in
Table 1.
The molecular structures of both compounds can formally be
interpreted as being composed of the distannoxane moiety
LSnOSnL that is complexed by the alkoxido-stannatrane
LSnOR to give the cluster of the type [(LSnOSnL)(LSnOR)]
(L = N(CH2CMe2O)2(CH2CH2O), R = t-Bu (7), 2,6-
Me2C6H3 (8·0.5C7H8)). Alternatively, compound 7 can also
be seen as [t-BuO(LSn)3O] in which three LSn+ cations are
bridged by one μ3-oxido, O2− (O11) and one μ3-t-butoxido, t-
BuO−, ligand.
The unit cell of 7 contains four Sn3-clusters. Two of these
clusters contain atrane cages showing Δ, Δ, Δ - and the other
two clusters contain atrane cages showing Λ, Λ, Λ -stereo-
chemistry. The situation in 8·0.5C7H8 is analogous with,
however, two Sn3-clusters in the unit cell.
In compound 7 the Sn(1), Sn(2), and Sn(3) atoms are
heptacoordinated and adopt distorted pentagonal bipyramidal
configurations with O(1)/O(11), O(5)/O(11), and O(7)/
O(11), respectively, occupying the axial positions. They are
linked by one μ3-oxido bridge (O(11)), one μ3-tert-butoxido
Figure 4. Molecular structure of compound 7 (ORTEP presentation
at 30% probability of the depicted atoms and atom numbering
scheme).
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2.485(4) Å (8·0.5C7H8) respectively 2.418(2) Å and 2.487(2)
Å (7) with the latter being the longest N−Sn distance in
stannatranes reported so far.
The 119Sn NMR spectrum in C6D6 of single crystals of 7 the
purity of which had been confirmed by powder X-ray diffraction
analysis (see Supporting Information, Figure S2) and elemental
analysis shows a resonance at −621 (2J(119Sn-117/119Sn) = 217
Hz). The satellite-to-signal-to-satellite integral ratio of
7.7:84.6:7.7 is consistent with the trimeric structure of 7 to
be retained in solution.
The 119Sn NMR spectrum of 8·0.5C7H8 in CDCl3 shows
three equally intense resonances at δ −533 (2J(119Sn-117/119Sn)
= 309 Hz, 225 Hz), −634 (2J(119Sn-117/119Sn) = 222 Hz, 90
Hz), and −703 (2J(119Sn-117/119Sn) = 306 Hz, 89 Hz) indicating
the cluster to be kinetically inert on the corresponding NMR
1
time scale. The same holds for the H and 13C NMR spectra
showing the expected resonances for the magnetically non-
equivalent CH2, C(Me)2, and CMe protons and carbon atoms,
respectively.
The ESI MS spectra of 7 and 8 show mass clusters centered
at m/z = 527.2, 846.3, and 978.2 which are assigned to [1 +
LSn]+, [LSnLHSnL + H]+, and [(LSn)2O + LSn]+ (L =
N(CH2CMe2O)2(CH2CH2O)), respectively. The latter mass
cluster is also present in the ESI MS spectrum of the t-
butoxido-substituted stannatrane 3 under the experimental
conditions employed.
The hydrolysis of the t-butoxido-substituted stannatrane 3 in
CD2Cl2 solution to which had been added one droplet of water
was studied in more detail by time-dependent 119Sn NMR
spectroscopy (Figure 7).
Figure 5. Molecular structure of compound 8·0.5C7H8 (ORTEP
presentation at 30% probability of the depicted atoms and atom
numbering scheme). The solvent molecule was removed by the
Squeeze routine of the program Platon.38.
bridge, and three atrane-μ2-oxygen atoms (O(3), O(6), O(9)).
The coordination pattern in compound 8·0.5C7H8 slightly
differs. The tin(IV) oxocluster 8·0.5C7H8 consists of one hexa-
(Sn1) and two hepta-coordinated (Sn(2), Sn(3)) tin atoms
which adopt distorted octahedral (Sn(1)) or pentagonal
bipyramidal (Sn(2), Sn(3)) configurations, respectively. They
are linked by a central μ3-oxido (O(11)) bridge and four
atrane-μ2-oxygen atoms (O(3), O(6), O(8), O(9)), whereas
the aryl-bound oxygen atom is not involved in any bridge. This
is the result of the aryloxido substituent being cis to the μ3-
oxido (O(11)) bridge; in contrast to the t-butoxido substituent
in 7 (Figure 6).
Figure 7. Stacked plot of time-dependent 119Sn NMR spectra of a
solution of compound 3 in CD2Cl2 to which had been added a droplet
of water.
In contrast to the hydrolysis in benzene that exclusively gave
the trinuclear tin oxocluster 7 (see discussion above), the
hydrolysis in CD2Cl2 appears to be more complex. Thus, the
spectrum recorded after 1 h showed, in addition to the signal
assigned to 7, three equally intense resonances at δ −535
(J(119Sn-O-117/119Sn) 248, 300 Hz; signal b), −637 (J(119Sn-
O-117/119Sn) 125, 245 Hz; signal d) and −691 (J(119Sn-
O-117/119Sn) 126, 298 Hz, signal f). With caution and in analogy
to the structure of the trinuclear tin oxocluster 8·0.5C7H8
(Figures 5, 6), these resonances are assigned to an isomer of 7
in which the t-butoxido substituent is cis to the μ3-oxido bridge.
After 5 h the intensity of the signals (b), (d), and (f) reached a
Figure 6. Simplified molecular structures (ball and stick) of
compounds 7 (left) and 8 (right) showing the t-butoxido substituent
in 7 to be trans and the aryloxido substituent in 8 to be cis to the μ3-
oxido (O(11)) bridge, as indicated by the black arrow. All carbon
atoms of the alkanolamine ligands and the methyl substituents at the
aryloxido group are omitted.
The O−Sn distances in compounds 7/8·0.5C7H8 vary
between 1.976(2)/1.978(3) Å and 2.430(2)/2.277(3) Å with
the bridging O−Sn distances being longer than nonbridging
ones. The N−Sn distances vary between 2.306(3) Å and
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Table 1. Selected Bond Distances (Å) and Angles (deg) for Compounds 7 and 8·0.5C7H8
7
8·0.5C7H8
7
8·0.5C7H8
Sn(1)−O(1)
Sn(1)−O(2)
Sn(1)−O(3)
Sn(1)−O(6)
Sn(1)−O(9)
Sn(1)−O(10)
Sn(1)−O(11)
Sn(1)−N(1)
Sn(2)−O(3)
Sn(2)−O(4)
Sn(2)−O(5)
Sn(2)−O(6)
Sn(2)−O(8)
Sn(2)−O(9)
1.981(2)
2.015(2)
2.119(2)
2.122(2)
1.993(3)
1.977(3)
2.142(3)
Sn(2)−O(10)
Sn(2)−O(11)
Sn(2)−N(2)
Sn(3)−O(3)
Sn(3)−O(6)
Sn(3)−O(7)
Sn(3)−O(8)
Sn(3)−O(9)
Sn(3)−O(10)
Sn(3)−O(11)
Sn(3)−N(3)
Sn(1)···Sn(2)
Sn(1)···Sn(3)
Sn(2)···Sn(3)
2.430(2)
2.054(2)
2.431(2)
2.109(2)
2.087(2)
2.485(3)
2.109(3)
2.033(3)
2.306(3)
2.124(3)
2.004(3)
1.978(3)
2.103(3)
2.277(3)
2.078(3)
2.209(3)
2.013(3)
2.081(3)
2.193(3)
2.010(3)
2.100(3)
2.389(3)
2.411(2)
2.047(2)
2.418(2)
1.981(2)
2.012(2)
2.090(2)
2.297(2)
2.089(2)
2.487(2)
3.198(3)
3.1835(3)
3.187(3)
2.003(2)
1.976(2)
2.110(2)
2.108(2)
3.1403(5)
O(1)−Sn(1)−O(2)
O(1)−Sn(1)−O(3)
O(1)−Sn(1)−O(6)
O(1)−Sn(1)−O(9)
O(1)−Sn(1)−O(10)
O(1)−Sn(1)−O(11)
O(1)−Sn(1)−N(1)
O(2)−Sn(1)−O(3)
O(2)−Sn(1)−O(6)
O(2)−Sn(1)−O(9)
O(2)−Sn(1)−O(10)
O(2)−Sn(1)−O(11)
O(2)−Sn(1)−N(1)
O(3)−Sn(1)−O(6)
O(3)−Sn(1)−O(9)
O(3)−Sn(1)−O(10)
O(3)−Sn(1)−O(11)
O(3)−Sn(1)−N(1)
O(6)−Sn(1)−O(10)
O(6)−Sn(1)−O(11)
O(6)−Sn(1)−N(1)
O(9)−Sn(1)−O(11)
O(9)−Sn(1)−N(1)
O(10)−Sn(1)−O(11)
O(10)−Sn(1)−N(1)
O(11)−Sn(1)−N(1)
O(3)−Sn(2)−O(4)
O(3)−Sn(2)−O(5)
O(3)−Sn(2)−O(6)
O(3)−Sn(2)−O(8)
O(3)−Sn(2)−O(11)
O(3)−Sn(2)−N(2)
O(4)−Sn(2)−O(5)
O(4)−Sn(2)−O(6)
O(4)−Sn(2)−O(8)
O(4)−Sn(2)−O(9)
O(4)−Sn(2)−O(10)
O(4)−Sn(2)−O(11)
O(4)−Sn(2)−N(2)
O(5)−Sn(2)−O(6)
O(5)−Sn(2)−O(8)
O(5)−Sn(2)−O(9)
O(5)−Sn(2)−O(10)
105.9(1)
101.6(1)
89.7(1)
108.2(1)
92.6(1)
O(5)−Sn(2)−O(11)
O(5)−Sn(2)−N(2)
O(6)−Sn(3)−O(7)
O(6)−Sn(2)−O(8)
O(6)−Sn(2)−O(9)
O(6)−Sn(2)−O(10)
O(6)−Sn(2)−O(11)
O(6)−Sn(2)−N(2)
O(8)−Sn(2)−O(11)
O(8)−Sn(2)−N(2)
O(9)−Sn(2)−O(10)
O(9)−Sn(2)−O(11)
O(9)−Sn(2)−N(2)
O(10)−Sn(2)−O(11)
O(10)−Sn(2)−N(2)
O(10)−Sn(2)−N(2)
O(11)−Sn(2)−N(2)
O(3)−Sn(3)−O(7)
O(3)−Sn(3)−O(8)
O(3)−Sn(3)−O(9)
O(3)−Sn(3)−O(10)
O(3)−Sn(3)−O(11)
O(3)−Sn(3)−N(3)
O(6)−Sn(3)−O(8)
O(6)−Sn(3)−O(9)
O(6)−Sn(3)−O(10)
O(6)−Sn(3)−O(11)
O(6)−Sn(3)−N(3)
O(7)−Sn(3)−O(8)
O(7)−Sn(3)−O(9)
O(7)−Sn(3)−O(10)
O(7)−Sn(3)−O(11)
O(7)−Sn(3)−N(3)
O(8)−Sn(3)−O(9)
O(8)−Sn(3)−O(10)
O(8)−Sn(3)−O(11)
O(8)−Sn(3)−N(3)
O(9)−Sn(3)−O(10)
O(9)−Sn(3)−O(11)
O(9)−Sn(3)−N(3)
O(10)−Sn(3)−O(11)
O(10)−Sn(3)−N(3)
O(11)−Sn(3)−N(3)
155.0(1)
78.3(1)
150.8(1)
75.0(1)
79.1(1)
73.4(1)
87.4(1)
91.7(1)
156.5(1)
79.1(1)
131.2(1)
83.8(1)
136.5(1)
69.1(1)
76.7(1)
71.9(1)
146.9(1)
81.1(1)
70.7(1)
71.2(1)
70.9(1)
126.1(1)
142.3(1)
89.0(1)
147.8(1)
91.6(1)
75.0(1)
136.2(1)
69.1(1)
84.0(1)
151.4(1)
65.2(1)
136.2(1)
99.5(1)
78.1(1)
123.9(1)
68.2(1)
77.0(1)
71.6(1)
69.3(1)
76.6(1)
152.0(1)
75.3(1)
74.5(1)
123.1(1)
89.4(1)
85.4(1)
139.6(1)
70.6(1)
76.3(1)
149.8(1)
129.5(1)
75.0(1)
159.0(1)
65.7(1)
75.2(1)
138.8(1)
106.3(1)
68.3(1)
135.6(1)
103.2(1)
141.2(1)
88.7(1)
146.9(1)
75.4(1)
84.4(1)
168.0(1)
74.4(1)
76.0(1)
87.1(1)
71.2(1)
69.6(1)
94.9(1)
108.9(1)
133.1(1)
135.9(1)
121.4(1)
123.1(1)
84.1(1)
90.7(1)
141.1(1)
78.7(1)
74.8(1)
147.6(1)
110.3(1)
115.3(1)
159.2(1)
107.0(1)
106.6(1)
91.3(1)
157.2(1)
76.6(1)
122.6(1)
149.7(1)
89.7(1)
73.8(1)
72.1(1)
75.5(1)
70.6(1)
67.4(1)
135.2(1)
124.1(1)
74.9(1)
107.5(1)
129.9(1)
84.0(1)
147.8(1)
91.9(1)
74.9(1)
101.2(1)
93.6(1)
74.3(1)
111.1(1)
81.6(1)
90.3(1)
90.5(1)
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Figure 8. 119Sn NMR spectrum of compound 9 in CD2Cl2. *,+, Δ, o, ε, × assign J(119Sn-O-117/119Sn) satellites, as discussed in the text.
maximum but had almost disappeared after 1 d and 23 h.
Instead, a number of new signals (a), (c), and (e) appeared that
are not assigned. Most interestingly, the spectrum had
simplified after 32 d and 4 h leaving three resonances (Figures
7, 8) at δ −535 (integral 2; J(119Sn-O-119Sn) = 384, 318 Hz,
J(119Sn-O-117Sn) = 369, 308 Hz, J(119Sn-O-119/117Sn) = 131
Hz), −589 (integral 1; J(119Sn-O-119Sn) = 317 Hz, J(119Sn-
O-117Sn) = 306 Hz, J(119Sn-O-119/117Sn) = 65 Hz), and −665
(integral 2; J(119Sn-O-119Sn) = 384 Hz, J(119Sn-O-117Sn) = 368
Hz, J(119Sn-O-119/117Sn) = 133 Hz), J(119Sn-O-119/117Sn) = 65
Hz)).
The molecular structure of the pentanuclear tin oxocluster
9·6H2O is shown in Figure 9. Selected bond distances and
angles are given in Tables 2 and 3, respectively.
These resonances are assigned to the pentanuclear tin
oxocluster 9 (Scheme 5) a few single crystals of which, as its
hexaaqua solvate 9·6H2O, were isolated from the NMR sample
and were analyzed by X-ray diffraction.
Table 2. Selected Bond Distances (Å) for Compound
9·6H2O
Sn(1)−O(1)
Sn(1)−O(2)
Sn(1)−O(3)
Sn(1)−O(6)
Sn(1)−O(7)
Sn(1)-O(8A)
Sn(1)−N(1)
Sn(2)−O(4)
Sn(2)−O(5)
Sn(2)−O(6)
Sn(2)−O(7)
Sn(2)−O(8)
Sn(2)−N(2)
Sn(3)−O(3)
Sn(3)−O(7)
Sn(3)−O(9)
2.039(3)
1.997(3)
2.160(3)
2.189(3)
2.077(3)
2.119(3)
2.377(4)
1.989(3)
2.026(3)
2.101(3)
2.019(3)
2.075(3)
2.316(4)
2.075(3)
2.048(3)
2.013(3)
Figure 9. Molecular structure of compound 9·6H2O (ORTEP
presentation at 30% probability of the depicted atoms and atom
numbering scheme). The water molecules were removed by the
Squeeze routine of the program Platon.38.
Compound 9·6H2O is a centrosymmetric pentanuclear tin
oxocluster composed of the tristannoxane moiety LSnOSn-
(OH)2OSnL (with Sn(2), Sn(3), Sn(2A)) to which two
hydroxido-substituted stannatrane moieties LSnOH (with
Sn(1), Sn(1A)) associate via (CH2)O→Sn and (H)O→Sn
donor−acceptor interactions.
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Table 3. Selected Angles (deg) for Compound 9·6H2O
O(1)−Sn(1)−O(2)
O(1)−Sn(1)−O(3)
O(1)−Sn(1)−O(6)
O(1)−Sn(1)−O(7)
O(1)−Sn(1)−O(8A)
O(1)−Sn(1)−N(1)
O(2)−Sn(1)−O(3)
O(2)−Sn(1)−O(6)
O(2)−Sn(1)−O(7)
O(2)−Sn(1)−O(8A)
O(2)−Sn(1)−N(1)
O(3)−Sn(1)−O(6)
O(3)−Sn(1)−O(7)
O(3)−Sn(1)−O(8A)
O(3)−Sn(1)−N(1)
O(6)−Sn(1)−O(7)
O(6)−Sn(1)−O(8A)
104.4(1)
133.9(1)
78.4(1)
147.5(1)
82.3(1)
75.8(1)
99.4(1)
88.8(1)
85.4(1)
169.7(1)
78.9(1)
141.4(1)
72.3(1)
80.7(1)
70.9(1)
70.8(1)
84.9(1)
O(6)−Sn(1)−N(1)
O(7)−Sn(1)−O(8A)
O(7)−Sn(1)−N(1)
O(8A)-Sn(1)−N(1)
O(4)−Sn(2)−O(5)
O(4)−Sn(2)−O(6)
O(4)−Sn(2)−O(7)
O(4)−Sn(2)−O(8)
O(4)−Sn(2)−N(2)
O(5)−Sn(2)−O(6)
O(5)−Sn(2)−O(7)
O(5)−Sn(2)−O(8)
O(5)−Sn(2)−N(2)
O(6)−Sn(2)−O(7)
O(6)−Sn(2)−O(8)
O(6)−Sn(2)−N(2)
O(7)−Sn(2)−O(8)
147.5(1)
84.9(1)
136.7(1)
110.6(1)
107.9(1)
142.1(1)
94.7(1)
99.4(1)
78.4(1)
77.9(1)
154.5(1)
78.0(1)
77.9(1)
73.7(1)
115.3(1)
76.8(1)
86.7(1)
O(7)−Sn(2)−N(2)
O(8)−Sn(2)−N(2)
Sn(1)−O(6)−Sn(2)
Sn(1)−O(7)−Sn(2)
Sn(1A)−O(8)−Sn(2)
Sn(1)−O(3)−Sn(3)
Sn(1)−O(7)−Sn(3)
Sn(2)−O(7)−Sn(3)
O(3)−Sn(3)−O(3A)
O(3)−Sn(3)−O(7)
O(3)−Sn(3)−O(7A)
O(3)−Sn(3)−O(9)
O(3)−Sn(3)−O(9A)
O(7)−Sn(3)−O(7A)
O(7)−Sn(3)−O(9)
O(7)−Sn(3)−O(9A)
O(9)−Sn(3)−O(9A)
119.4(1)
153.8(1)
103.8(1)
111.05(1)
141.1(2)
104.3(1)
108.4(1)
135.1(1)
156.9(1)
74.7(1)
88.8(1)
96.8(1)
99.8(1)
89.6(2)
91.5(1)
174.4(1)
88.0(2)
The Sn(1) atom is seven-coordinate and adopts a distorted
pentagonal-bipyramidal configuration with the O(2) and
O(8A) atoms occupying the apical and the N(1), O(1),
O(3), O(6) and O(7) atoms occupying the equatorial
positions. The distortion from the ideal geometry is manifested
by the apical O(2)−Sn(1)−O(8A) angle of 169.7(1)° and the
equatorial angles ranging between 70.8(1) (O(6)−Sn(1)−
O(7)) and 78.4(1)° (O(1)−Sn(1)−O(6)). The Sn(2) atom is
six-coordinate by N(2), O(4), O(5), O(6), O(7), and O(8)
and shows a strongly distorted octahedral configuration with
trans angles ranging between 142.1(1) (O(4)−Sn(2)−O(6))
and 163.8(1)° (N(2)−Sn(2)−O(8)). The Sn(3) atom is six-
coordinate as well with the O(3), O(3A), O(7), O(7A), O(9),
and O(9A) occupying the edges of a distorted octahedron. The
trans angles range between 156.9(1) (O(3)−Sn(3)−O(3A))
and 174.4(1)° (O(7)−Sn(3)−O(9A)).
same effect of dimerization is observed on going from the
monomeric t-butoxido-substituted stannatrane 3 to the
corresponding derivative 4·C7H8. The latter differs in its
composition from 3 by only one methylene group. It can be
envisaged that further reducing the methyl-substitution to 2-
fold and/or by having other chain-length combinations might
give oligo- or even polymeric stannatranes.
Furthermore, we demonstrated that the controlled hydrolysis
of the t-butoxido- as well as the aryloxido-substituted
stannatranes gives access to novel tri- and pentanuclear tin
oxoclusters such as 7, 8·0.5C7H8, and 9·6H2O. Apparently,
aminoalkoholates are suitable ligands for stabilizing oligomeric
intermediates along the hydrolysis pathway of tin alkoxides.
With this approach a deeper insight into the mechanism of tin
alkoxide hydrolysis should be possible and will be part of
further studies.
The Sn(1)−N(1) distance of 2.377(4) Å is longer than the
Sn(2)−N(2) distance of 2.316(4) Å. Both distances are shorter
than the corresponding Sn−N distances in the trinuclear tin
oxoclusters 7 and 8·0.5C7H8 as well as in compounds 4 and 5,
but longer than in compound 3. The Sn−O distances vary
between 1.989(3) (Sn(2)−O(4)) and 2.189(3)° (Sn(1)−
O(6)).
The hydrolysis of compound 4 was also studied by time-
dependent 119Sn NMR spectroscopy (Supporting Information,
Figure S3). After 10 d, the reaction seems to be finished as only
one resonance at δ −432 (ν1/2 13 Hz) is observed that lacks
any J(119Sn-O-117/119Sn) couplings. With caution, this and the
chemical shift being close to that for compound 4 (δ −400)
suggest the formation of [N(CH2CMe2O)2(CH2)3OSnOH]2.
However, no single crystalline material suitable for X-ray
diffraction analysis could be isolated yet to confirm this
hypothesis.
EXPERIMENTAL SECTION
■
General Procedures. All experimental manipulations with tin
compounds were carried out under argon atmosphere using Schlenk
techniques. All solvents were purified by distillation under argon from
appropriate drying agents according to standard procedures.39 1,1′-(2-
Hydroxyethylazanediyl)bis(2-methylpropan-2-ol)34 and tin tetra-t-
butoxide37 were prepared according to literature methods. The
NMR spectra were recorded, unless otherwise stated, at room
temperature on Bruker DRX 500, Bruker DRX 400, and Bruker
DPX 300 spectrometers. Chemical shifts δ are given in ppm and are
referenced to the solvent peaks with the usual values calibrated against
tetramethylsilane (1H, 13C) and tetramethylstannane (119Sn).
Elemental analyses were performed on a LECO CHNS-932 analyzer.
The electrospray mass spectra were recorded on a Thermoquest
Finnigan instrument using CH2Cl2 as a mobile phase. Melting points
are uncorrected and were measured on a Buchi M-560.
̈
Crystallography. All intensity data were collected with an
Xcalibur2 CCD diffractometer (Oxford Diffraction) using Mo−Kα
radiation at 110 K. The structures were solved with direct methods
using SHELXS-9740 and refinements were carried out against F2 by
using SHELXL-97.40 All non-hydrogen atoms were refined using
anisotropic displacement parameters. The C−H hydrogen atoms were
positioned with idealized geometry and refined using a riding model.
In compound 8·0.5C7H8 the solvate molecule was found severely
disordered and was removed by Squeeze (Platon)38 to improve the
main part of the structure. In compound 9·6H2O the water molecules
could not be located properly and were removed by the Squeeze
routine of the program Platon38 to improve the main part of the
structure. CCDC-915085 (3), CCDC-902025 (4·C7H8), CCDC-
CONCLUSION
■
We have shown that the degree of self-assembly in the solid
state of inorganic stannatranes can in general be controlled by
modification of the steric hindrance and/or the chain length of
the aminoalkoholate moiety as well as by the identity of the
axial substituents. In particular, reducing the 6-fold methyl-
substitution in the monomeric stannatrane N-
(CH2CMe2O)3SnOC6H3Me2-2,623 to 4-fold methyl-substitu-
tion in compound 5 gives a dimeric structure for the latter. The
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902026 (5), CCDC-902027 (7), CCDC-902028 (8·0.5 C7H8), and
CCDC-915086 (9·6H2O) contain the supplementary crystallographic
data for this paper. This data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
260−262 °C (decomposition). Anal. Calcd. for C30H62N2O8Sn2 (%):
C 44.1, H 7.7, N 3.4. Found: C 44.5, H 7.3, N 3.3. MS (ESI +): m/z =
202.1 [2 − OH]+, 220.1 [2 + H]+, 818.4 [M+H]+, 1020.3
[ { N ( C H 2 C M e 2 O ) 2 ( C H 2 C H 2 C H 2 O ) S n } 2 O
+
N -
(CH2CMe2O)2(CH2CH2CH2O)Sn]+, 1074.2.
Synthesis of Bis(2-methyl-2-hydroxypropyl)(3-
hydroxypropyl)amine (2). A mixture of 3-aminopropan-1-ol (2.09
g, 27.8 mmol) and isobutylenoxide (4.10 g, 57.0 mmol, 2.05 equiv)
was stirred in a Teflon sealed glass vessel and heated at 110 °C for 48
h. The reaction mixture was diluted with diethyl ether, dried with
MgSO4, filtrated, and the volatiles of the filtrate were removed under
reduced pressure. Compound 2 was obtained as colorless oil (5.85 g,
26.7 mmol, 96%) that crystallized upon standing.
Synthesis of Bis{1-(2,6-dimethylphenolato)-(2,8,9-trioxa-5-
aza-3,3,7,7-tetramethyl-1-stanna-tricyclo[3.3.3.01.5]undecane)}
(5). To a stirred solution of 3 (2.168 g, 5.50 mmol) in dry toluene
(100 mL) was added a toluene solution (50 mL) of 2,6-
dimethylphenol (0.672 g, 5.50 mmol). The mixture was concentrated
to the half by azeotropic distillation of t-BuOH/toluene. Cooling to
room temperature provided a colorless amorphous solid that was
filtered. Recrystallization from toluene and subsequent washing with
cold toluene gave colorless block-like crystals of 5 (1.799 g, 2.03
mmol, 74%).
1H NMR (400.13 MHz, CDCl3, 298 K): δ 4.07 (s, 2H, CMe2OH),
3
3
3.68 (t, 3H, J(1H-1H) = 5.9 Hz, CH2OH), 2.69 (t, 2H, J(1H-1H) =
1H NMR (300.13 MHz, CD2Cl2, 294 K): δ 6.92 (d, 3J(1H-1H) = 7.3
Hz, 2H, m-H), 6.68 (t, 3J(1H-1H) = 7.4 Hz, 1H, p-H), 3.89 (t,
2J(1H-1H) = 5.3 Hz, J(1H-117/119Sn) = 88.3 Hz, 2H, CH2O), 3.06 (t,
6.8 Hz, NCH2CH2), 2.51 (s, 4H, NCH2CMe2), 1.65 (not resolved,
1
2H, NCH2CH2), 1.16 (s, 12H, J(1H-13C) = 125.4 Hz, C(CH3)2).
13C{1H} NMR (100.63 MHz, CDCl3, 298 K): δ 71.1 (s, NCH2CMe2),
2J(1H-1H) = 5.5 Hz, J(1H-117/119Sn) = 17.9 Hz, 2H, NCH2CH2), 2.90
68.3 (s, C(CH3)2), 61.0 (s, NCH2CH2), 57.0 (s, CH2OH), 30.1 (s,
NCH2CH2), 28.1 (s, C(CH3)2). Mp. 53−55 °C. Anal. Calcd. for
C11H25NO3 (%): C 60.2, H 11.5, N 6.4. Found: C 59.8, H 11.5, N 6.4.
MS (ESI +): m/z = 202.2 [C11H24NO2]+, 220.2 [2 + H]+.
Synthesis of 1-tert-Butanolato-(2,8,9-trioxa-5-aza-3,3,7,7-
tetramethyl-1-stanna-tricyclo[3.3.3.01.5]undecane) (3). To a
stirred solution of tin(IV)-tert-butoxide (2.65 g, 6.45 mmol) in dry
toluene (120 mL) was added within 10 min at room temperature a
solution of 1 (1.33 g, 6.48 mmol) in dry toluene (80 mL). After
concentrating the mixture by azeotropic distillation the remaining
volatiles were removed under reduced pressure. Compound 3 (2.54 g,
3.23 mmol, quantitative) was obtained as colorless solid. Single crystals
were obtained from its toluene solution at 4 °C.
2
2
(d, J(1H-1H) = 13.3 Hz, 2H, NCH−HACMe2), 2.77 (d, J(1H-1H) =
13.3 Hz, 2H, NCH−HBCMe2), 2.26 (s, J(1H-117/119Sn) = 7.9 Hz, 6H,
o-CH3), 1.32 (s, 12H, C(CH3)2). 13C{1H} NMR (75.48 MHz,
CD2Cl2, 294 K): δ 157.0 (s, Ci), 129.4 (s, Cp), 128.2 (s,
J(13C-117/119Sn) = 11.7 Hz, Cm)), 120.0 (s, J(13C-117/119Sn) = 11.7
Hz, Co), 69.5 (s, J(13C-117/119Sn) = 20.4 Hz, C(CH3)2), 67.0 (s,
J(13C-117/119Sn) = 47.9 Hz, NCH2CMe2), 61.6 (s, NCH2CH2), 58.7 (s,
J(13C-117/119Sn) = 17.7 Hz, CH2O), 31.6 (s, J(13C-117/119Sn) = 30.8 Hz,
C(CH3)2), 31.1 (s, J(13C-117/119Sn) = 31.1 Hz, C(CH3)2), 17.2 (s, o-
(CH3)). 119Sn{1H} NMR (111.87 MHz, CD2Cl2, 294 K): δ −335 (s).
Mp. 194−196 °C. Anal. Calcd. for C36H58N2O8Sn2 (%): C 48.9, H 6.6,
N 3.2. Found: C 49.1, H 6.8, N 3.1. MS (ESI +): m/z = 188.2 [1 −
OH]+, 206.2 [1 + H]+, 1416.5.
1H NMR (300.13 MHz, CD2Cl2, 295 K): δ 3.85 (t, 3J(1H-1H) = 5.4
Hz, J(1H-119Sn) = 85.2 Hz, J(1H-117Sn) = 82.0 Hz, 2H, CH2O), 3.00
(t, 3J(1H-1H) = 5.5 Hz, 2H, NCH2CH2), 2.83 (d, 2J(1H-1H) = 13.2 Hz,
2H, NCH−HACMe2), 2.71 (d, 2J(1H-1H) = 13.2 Hz, 2H, NCH−
HBCMe2), 1.29 (s, 9H, C(CH3)3), 1.27 (s, 6H, C(CH3)2), 1.26 (s, 6H,
C(CH3)2). 13C{1H} NMR (75.48 MHz, CD2Cl2, 295 K): δ 72.0 (s,
C(CH3)3), 68.8 (s, J(13C-117/119Sn) = 20.7 Hz, C(CH3)2), 68.0 (s,
J(13C-117/119Sn) = 47.6 Hz, NCH2CMe2), 61.6 (s, J(13C-117/119Sn) =
52.2 Hz, NCH2CH2), 58.4 (s, J(13C-117/119Sn) = 18.8 Hz, CH2O), 33.1
Synthesis of Bis{1-(2,6-dimethylphenolato)-(2,9,10-trioxa-6-
aza-8,8,11,11-tetramethyl-1-stanna-tricyclo-[4.3.3.01.6]-
dodecane)} (6). In analogy to the procedure for the synthesis of
compound 5, the reaction of 4 (1.00 g, 2.45 mmol) with 2,6-
dimethylphenol (0.30 g, 2.45 mmol) provided compound 6 (0.90 g,
0.99 mmol, 81%) as colorless microcrystalline solid.
1H NMR (500.13 MHz, CD2Cl2, 303 K): δ 6.88 (d, 3J(1H-1H) = 7.4
Hz, 2H, m-H), 6.68 (t, 3J(1H-1H) = 7.4 Hz, 1H, p-H), 4.31 (t,
2J(1H-1H) = 5.0 Hz, J(1H-117/119Sn) = 75.6 Hz, 2H, CH2O), 3.23 (t,
3
(s, J(13C-117/119Sn) = 26.9 Hz, C(CH3)3), 31.7 (s, J(13C-117/119Sn) =
29.4 Hz, C(CH3)2), 31.2 (s, J(13C-117/119Sn) = 30.0 Hz, C(CH3)2).
119Sn{1H} NMR (111.87 MHz, CD2Cl2, 294 K): δ −320 (s). Mp.
2
2J(1H-1H) = 4.7 Hz, 2H, NCH2CH2), 2.91 (d, J(1H-1H) = 13.1 Hz,
2H, NCH−HACMe2), 2.76 (d, 2J(1H-1H) = 13.2 Hz, 2H, NCH−
HBCMe2), 2.25 (s, 4H, o-(CH3)), 2.23 (s, 2H, o-(CH3)), 1.91−1.82
(not resolved, 2H, CH2CH2CH2), 1.38 (s, 6H, C(CH3)2), 1.32 (s, 6H,
C(CH3)2). 13C{1H} NMR (125.77 MHz, CD2Cl2, 303 K): δ 157.8 (s,
Ci), 152.6 (s, Ci), 129.6 (s, Cp), 128.8 (s, Cm), 128.0 (s, Cm), 123.4 (s,
Cp), 120.3 (s, Co), 119.2 (s, Co), 69.1 (s, C(CH3)2), 68.8 (s, CH2O),
68.6 (s, J(13C-117/119Sn) = 46.8 Hz, NCH2CMe2), 63.0 (s, NCH2CH2),
31.7 (s, J(13C-117/119Sn) = 34.1 Hz, C(CH3)2), 30.5 (s, J(13C-117/119Sn)
= 34.4 Hz, C(CH3)2), 30.5 (s, CH2CH2CH2), 17.4 (s, o-CH3), 15.9 (s,
o-CH3). 119Sn{1H} NMR (111.87 MHz, CD2Cl2, 294 K): δ −418 (s,
integral 1), −431 (s, integral 0.08). Mp. 217−220 °C. Anal. Calcd. for
C38H62N2O8Sn2 (%):C 50.0, H 6.9, N 3.1. Found: C 49.6, H 6.5, N
3.1. MS (ESI +): m/z = 184.1 [HN(CH2CMe2OH)2 + Na]+, 202.1 [2
− OH]+, 220.1 [2 + H]+, 555.3 [N(CH2CMe2O)2(CH2CH2CH2O)Sn
+ 2]+, 685.2 [{N(CH2CMe2O)2(CH2CH2CH2O)Sn}2O + H]+ 1020.3
194−196 °C. MS (ESI +): m/z = 170.2 [C10H20NO]+, 188.2 [1 −
OH]+, 206.2 [1 + H]+, 978.2 [(LSn)2O + LSn]+, 1466.8.
Synthesis of Bis{1-tert-butanolato-(2,9,10-trioxa-6-aza-
8,8,11,11-tetramethyl-1-stanna-tricyclo-[4.3.3.01.6]dodecane)}
(4). To a stirred solution of tin(IV)-tert-butoxide (4.10 g, 9.97 mmol)
in dry toluene (120 mL) was added within 10 min at room
temperature a solution of 2 (2.19 g, 9.99 mmol) in dry toluene (80
mL). After concentrating the mixture by azeotropic distillation and
recrystallization from toluene, compound 4 crystallized as its toluene
solvate 4·C7H8 (3.09 g, 3.40 mmol, 68%) upon storage at −15 °C.
1H NMR (300.13 MHz, CD2Cl2, 295 K): δ 7.32−7.07 (not
resolved, 2.5H, toluene), 4.28 (t, 3J(1H-1H) = 5.1 Hz, J(1H-117/119Sn) =
3
72.3 Hz, 2H, CH2O), 3.15 (t, J(1H-1H) = 5.1 Hz, 2H, NCH2CH2),
2.83 (d, 2J(1H-1H) = 13.1 Hz, 2H, NCH−HACMe2), 2.67 (d,
2J(1H-1H) = 13.1 Hz, 2H, NCH−HBCMe2), 2.34 (s, 1.5H, toluene),
[ { N ( C H 2 C M e 2 O ) 2 ( C H 2 C H 2 C H 2 O ) S n } 2 O
+
N -
1
1.87−1.74 (not resolved, 2H, CH2CH2CH2), 1.34 (s, J(1H-13C) =
(CH2CMe2O)2(CH2CH2CH2O)Sn]+, 1074.8.
125.3 Hz, 6H, C(CH3)2), 1.28 (s, 1J(1H-13C) = 125.8 Hz, 6H,
Synthesis of (μ3-oxido)(μ3-tert-Butanolato)-tris(2,8,9-trioxa-
5-aza-3,3,7,7-tetramethyl-1-stanna-tricyclo[3.3.3.01.5]-
undecane) [(μ3-O)(μ3-Ot-Bu){Sn(OCH2CH2)(OCMe2CH2)2N}3] (7).
To a solution of 3 (1.12 g, 2.85 mmol) in dichloromethane water
(slight excess) was added to form a two-phase system. Crystallization
of the product began at the phase boundary and within hours
compound 7 (0.41 g, 0.39 mmol, 41%) crystallized as colorless blocks
which assembled at the bottom of the flask. The crystalline material
was isolated, dried under reduced pressure, and the homogeneity of
the bulk material was confirmed by elemental analysis and powder X-
ray diffraction analysis.
1
C(CH3)2), 1.26 (s, J(1H-13C) = 124.6 Hz, 9H, C(CH3)3). 13C{1H}
NMR (75.48 MHz, CD2Cl2, 295 K): δ 138.1 (s, toluene), 129.2 (s,
toluene), 128.4 (s, toluene), 125.5 (s, toluene), 71.3 (s,
J(13C-117/119Sn) = 37.6 Hz, C(CH3)3), 68.5 (s, J(13C-117/119Sn) =
36.4 Hz, C(CH3)2), 68.5 (s, J(13C-117/119Sn) = 24.8 Hz, CH2O), 68.4
(s, J(13C-117/119Sn) = 45.7 Hz, NCH2CMe2), 63.0 (s, NCH2CH2), 33.1
3
(s, J(13C-117/119Sn) = 26.4 Hz, C(CH3)3), 31.8 (s, J(13C-117/119Sn) =
32.6 Hz, C(CH3)2), 31.2 (s, J(13C-117/119Sn) = 33.5 Hz, C(CH3)2),
30.5 (s, J(13C-117/119Sn) = 48.7 Hz, CH2CH2CH2), 21.4 (s, toluene).
119Sn{1H} NMR (111.87 MHz, CD2Cl2, 295 K): δ −400 (s). Mp.
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Article
1H NMR (400.13 MHz, CD2Cl2, 300 K): δ 4.09−3.92 (m, 1H,
OCH2), 3.92−3.66 (not resolved, 4H, OCH2), 3.66−3.52 (m, 1H,
OCH2), 3.15−2.30 (not resolved, 18H, NCH2), 1.50−1.00 (not
resolved, 45H, CH3). 119Sn{1H} NMR (111.86 MHz, C6D6, 298 K): δ
−621 (s, 2J(119Sn-117/119Sn) = 217 Hz). Mp. 252−253 °C
(decomposition). Anal. Calcd. for C34H69N3O11Sn3 (%): C 38.8, H
6.6, N 4.0. Found: C 38.7, H 6.6, N 3.9. MS (ESI +): m/z = 170.1
[C10H20NO]+, 188.2 [1 − OH]+, 206.2 [1 + H]+, 527.2 [1 + LSn]+,
846.3 [LSnLHSnL + H]+, 978.2 [(LSn)2O + LSn]+, 1455.3, 1467.5,
1806.7, 1825.6.
C(CH3)2, 9), 30.4 (s, C(CH3)2, 9), 28.5 (C(CH3)2, 1, 9). 119Sn{1H}
NMR (111.87 MHz, CD2Cl2, 294 K): δ −535 (s, integral 2,
J(119Sn-119Sn) = 384 Hz, J(119Sn-117Sn) = 369 Hz, J(119Sn-119Sn) = 318
Hz, J(119Sn-117Sn) = 308 Hz, J(119Sn-119/117Sn) = 131 Hz, Sn(2)),
−589 (s, integral 1, J(119Sn-119Sn) = 317 Hz, J(119Sn-117Sn) = 306 Hz,
J(119Sn-119/117Sn) = 65 Hz, Sn(3)), −665 (s, integral 2, J(119Sn-119Sn)
= 384 Hz, J(119Sn-117Sn) = 368 Hz, J(119Sn-119/117Sn) = 133 Hz,
J(119Sn-O-119/117Sn) = 65 Hz), Sn(1)). MS (ESI +): m/z = 188.2 [1 −
OH]+, 206.2 [1 + H]+, 228.1 [1 + Na]+, 278.2, 527.2 [1 + LSn]+,
848.3, 978.2 [(LSn)2O + LSn]+, 1316.7, 1386.4, 1465.4, 1485.5 [9 −
OH]+, 1591.8 [9 + 5H2O + H]+, 1634.5, 1805.2. Because only rather
small amounts of 9·6H2O were isolated, no elemental analysis was
performed.
Synthesis of (μ3-oxido)-(2,6-Dimethylphenolato)-tris(2,8,9-
trioxa-5-aza-3,3,7,7-tetramethyl-1-stanna-tricyclo[3.3.3.01.5]-
undecane) [(μ3 -O)(2,6-Me2 C6 H3 -O){Sn(OCH2 CH2 )-
(OCMe2CH2)2N}3] (8). A solution of 5 (1.16 g, 1.31 mmol) in
toluene was stored at −20 °C in a Schlenk flask that had not been
closed properly. Within several weeks and after diffusion of water, the
tin oxocluster 8 (0.54 g, 0.47 mmol, 54%) crystallized as its toluene
solvate 8·0.5C7H8 in the form of colorless plates.
ASSOCIATED CONTENT
* Supporting Information
■
S
Molecular structure of compound 3 (Figure S1). X-ray powder
diffraction pattern of compound 7 (Figure S2). 119Sn NMR
spectra showing the hydrolysis of compound 4 (Figure S3).
CIF file and tables showing crystal data and structure
refinement. This material is available free of charge via the
Internet at http://pubs.acs.org.
1H NMR (300.13 MHz, CDCl3, 294 K): δ 7.30−7.21 (not resolved,
2.5H, toluene), 6.78 (d, 3J(1H-1H) = 7.4 Hz, 2H, m-H), 6.49 (t,
3J(1H-1H) = 7.3 Hz, 1H, p-H), 4.69−4.48 (not resolved, 1H, CH2),
4.12−3.74 (not resolved, 1H, CH2), 4.12−3.74 (not resolved, 1H,
CH2), 3.67−3.51 (not resolved, 1H, CH2), 3.50−3.35 (not resolved,
1H, CH2), 3.34−3.20 (not resolved, 1H, CH2), 3.18−2.51 (not
resolved, 16H, CH2), 2.37 (s, 6H, o-CH3), 2.24 (s, 1.5H, toluene), 1.44
(s, 3H, C(CH3)2), 1.38 (s, 3H, C(CH3)2), 1.32 (s, 6H, C(CH3)2), 1.24
(s, 3H, C(CH3)2), 1.17 (s, 6H, C(CH3)2), 1.10 (s, 6H, C(CH3)2), 0.97
(s, 3H, C(CH3)2), 0.92 (s, 3H, C(CH3)2), 0.89 (s, 3H, C(CH3)2).
119Sn{1H} NMR (111.85 MHz, CDCl3, 295 K): δ −533
AUTHOR INFORMATION
Corresponding Author
*E-mail: klaus.jurkschat@tu-dortmund.de.
■
Notes
(2J(119Sn-117/119Sn) = 309 Hz; 225 Hz), −634 (2J(119Sn-117/119Sn) =
222 Hz; 90 Hz), −703 (2J(119Sn-117/119Sn) = 306 Hz; 89 Hz). Mp.
2 4 3 − 2 4 5 ° C ( d e c o m p o s i t i o n ) . A n a l . C a l c d . f o r
C38H69N3O11Sn3·0.5C7H8 (%): C 43.5, H 6.4, N 3.7. Found: C
43.7, H 6.3, N 3.8. MS (ESI +): m/z = 188.2 [1 − OH]+, 206.2 [1 +
H]+, 339.1 [1 + HN(CH2CMe2OH)(CH2CH2OH) + H]+, 527.2 [1 +
LSn]+, 846.5 [LSnLHSnL + H]+, 978.3 [(LSn)2O + LSn]+.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
T.Z. is grateful to the Fonds der Chemischen Industrie for a
scholarship. We thank Mrs. S. Marzian for recording the ESI
mass spectra and the anonymous reviewers for valuable hints.
Synthesis of Bis(μ3-oxido)-bis(μ3-hydroxido)-tetrakis(2,8,9-
trioxa-5-aza-3,3,7,7-tetramethyl-1-stanna-tricyclo[3.3.3.01.5]-
undecane)-stannanediol (9). (A) To a solution of 3 in CD2Cl2 in a
NMR tube was added a droplet of water. The hydrolysis of compound
3 was monitored by 119Sn{1H} NMR measurements, which showed
that the conversion to compound 9 was completed within 32 days.
(B) In a NMR tube compound 7 was dissolved in nondried CD2Cl2.
119Sn{1H} NMR data showed that the conversion to compound 9 was
DEDICATION
■
Dedicated to Professor Kieran Molloy on the occasion of his
60th birthday.
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