Functionalization of Sn/S Clusters with Hetero- and Polyaromatics

Article abstract of DOI:10.1021/acs.organomet.5b00295

We report a mild and all-purpose method to synthesize several hydrazone-functionalized homo- and heteroaromatic molecules, as well as the attachment of the latter to organic functionalized Sn/S clusters. It turned out that the size of the aromatic system has a great influence on the crystallization tendency of the products, which were characterized by NMR spectroscopy, mass spectrometry, and/or single-crystal X-ray diffraction. The last technique indicates the presence of intramolecular or intermolecular stacking of the aromatic rings.

Full text of DOI:10.1021/acs.organomet.5b00295

Article
pubs.acs.org/Organometallics
Functionalization of Sn/S Clusters with Hetero- and Polyaromatics
Eliza Leusmann, Felix Schneck, and Stefanie Dehnen*
Philipps-Universitat Marburg, Fachbereich Chemie and Wissenschaftliches Zentrum fur Materialwissenschaften,
̈
̈
Hans-Meerwein-Straße 4, D-35043 Marburg, Germany
S
* Supporting Information
ABSTRACT: We report a mild and all-purpose method to
synthesize several hydrazone-functionalized homo- and heter-
oaromatic molecules, as well as the attachment of the latter to
organic functionalized Sn/S clusters. It turned out that the size
of the aromatic system has a great influence on the
crystallization tendency of the products, which were
characterized by NMR spectroscopy, mass spectrometry,
and/or single-crystal X-ray diffraction. The last technique
indicates the presence of intramolecular or intermolecular π
stacking of the aromatic rings.
(transition) metal complexes, such as ferrocene and ruth-
enocene, on the surface of inorganic clusters,9−11 in particular
tin oxo clusters,12 or fullerenes.13
INTRODUCTION
■
The functionalization of inorganic clusters has been one of the
most intriguing goals of cluster chemistry. Three different
routes might be discriminated here, at least. The first is where
the organic ligand shell has a purely protective role to inhibit
thermodynamically preferred particle growth by kinetic
stabilization of the (intermediate) cluster.1 The second is
where the organic ligands possess donor atoms or aromatic
groups for further coordinative or dispersive interaction with
metal atoms, ions, or metal surfaces.2,3 The third is where the
organic molecules possess a functional group, making them
reactive toward other molecules with complementary function-
ality.
One of our current aims is the synthesis and further
derivatization of tetrel chalcogenide clusters with organic
ligands of the latter class.4,5 For this, we have been using R1
= −CMe2CH2C(O)Me, a keto-functionalized ligand that was
introduced for the first time in 1978 as its tin trichloride
derivative Cl3SnCMe2CH2C(O)Me.6 On the basis of this,
reactions with hydrazine hydrate or organic hydrazine
derivatives have allowed for an extension of the ligand shell
for different purposes.
A very challenging goal in this context has been the
attachment of molecules with chelating groups for (transition)
metal ion capture. Generally, the capture of (transition) metal
ions can enhance the electronic properties of molecules, such as
phosphorescence through Eu(III) and Tb(III) ions in
bipyridine ligands on gold nanoparticles, or photon capture
in dye-sensitized solar cells through connecting terpyridine
units on a silicon surface, adding Fe(II) ions, and saturating
them with a further ligand.7 The first example in this direction
was realized by the generation of a bispyridine-functionalized
Sn/S cluster capable of sequestering Zn2+ ions, which led to the
formation of a new Zn/Sn/S/Cl cluster.8 Another strategy for
the installation of metal complexes on a metal chalcogenide
cluster surface has been the attachment of preformed
Herein, we present a third approach, which deals with the
decoration of the cluster with aromatic molecules that can serve
as complexing agents. A few molecules have been known to
bear Sn atoms and aromatics.14 In an extension of preliminary
work with phenyl or bis-naphthyl groups as simple homoar-
omatic ligands,4,15 we first concentrated on further (poly)-
homoaromatic groups such as benzyl, mononaphthyl, and
anthracenyl groups and continued the study by introduction of
heteroaromatic moieties such as quinolinyl groups.
RESULTS AND DISCUSSION
■
Upon synthesis of hydrazones from aromatic aldehydes or
ketones by a newly developed, mild, and universally applicable
method, all of these hydrazones (and a commercially available
hydrazine derivative) were reacted with the Sn/S cluster A with
stirring at room temperature to form Sn/S clusters with new
aromatic ligands. The title compounds comprise the first
examples of Sn/S clusters that are decorated by heteroaromatic
or polyaromatic molecules. For the latter, we have observed a
clear decrease in the tendency to form single crystals with an
increasing number of aromatic rings (e.g., phenyl > naphthyl >
anthracenyl/phenanthryl derivatives). It is so far unclear
whether a suitable packing of the molecules is hampered by
ever bulkier ligands that may not be in a position to realize the
desired π-stacking interaction or whether stronger interactions
in solution inhibit crystallization.
A rearrangement of the inorganic cluster core occurs along
with all reactions, as a consequence of the size and rigidity of
the molecules used for the organic ligand extension, as
previously observed for the attachment of further bulky
Received: April 8, 2015
© XXXX American Chemical Society
A
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a
Scheme 1. Condensation Reaction at the Organic Groups of A, Given for Hydrazones as Reactants
a
The step is instantly followed in situ by rearrangement into a corresponding defect-heterocubane cation, which reversibly aggregates to a doubly μ-S
bridged “dimer” of defect-heterocubane units. Cl− ions stem from the solvent CH2Cl2. All given side products were identified by standard analytical
methods.
Figure 1. Molecular structure of the cluster in 6 with disorder in transparent mode. Thermal ellipsoids are shown with 50% probability, organic
moieties are shown as wires, and H atoms are omitted for clarity. Atom color code: yellow, S; gray, Sn; blue, N; red, H. H10 shows an interaction
with one of the disordered aromatic rings (C21A−C26A).
ligands.4,5,8,9 Hence, instead of the composition and topology of
A, all clusters reported herein are based on defect-
heterocubane-type [Sn3S4] moieties, as confirmed by the
detection of [(RSn)3S4]+ species by ESI+ mass spectrometry
(see the Experimental Section) and/or crystal structures. Single
crystals suitable for X-ray diffraction (see Table S1 in the
Supporting Information) were obtained for compounds 6−8
and 10, which indicate crystallization of the compounds as two
doubly μ-S bridged defect-heterocubane units [(RSn)4Sn2S10],
thus a “dimeric” arrangement, which cannot be retained under
ESI-MS conditions in agreement with our previous find-
ings.4,5,8,9 An equilibrium is likely to exist in solution with
differing amounts of the respective “monomeric” or “dimeric”
species, as a function of the nature and bulkiness of the terminal
ligands and the corresponding stability and solubility of the
resulting clusters (Scheme 1). According to our observations to
date, including NMR data, the larger, neutral cluster has the
overall higher crystallization tendency, while the smaller,
cationic cluster is usually predominant in solution.
surrounded in a distorted-trigonal-bipyramidal manner, either
by one C atom, three S atoms, and one intramolecular N
coordination or by five S atoms, respectively. The distortion of
the trigonal bipyramids is more severe around the latter,
“inorganic” Sn atom.
The benzyl-decorated Sn/S cluster in 6 (Figure 1)
crystallizes in the triclinic space group P1 with one formula
̅
unit per unit cell. The Sn−S distances (Table S2 in the
Supporting Information) in the molecular structure of the
centrosymmetric cluster vary between 2.3830(19) Å (Sn3−S5)
and 2.819(2) Å (Sn3−S4), with the shortest and the longest
bonds being cis to each other.
Sn−C distances (2.174(7)−2.32(29) Å) and Sn−N distances
(2.420(6)−2.50(2) Å) are in the expected range. Due to the
formation of five-membered rings with the organic ligands,
which do not allow for 90° angles between the two Sn-bonded
atoms (75.4(3)−76.9(7)°), the trigonal bipyramids around the
organyl-substituted Sn atoms Sn1 and Sn2 are slightly distorted.
Equatorial angles are 100.0(6)−124.0(5)° (C−Sn−S) and
91.02(7)−115.91(8)° (S−Sn−S); the apical atoms (N, S) are
oriented at angles of 169.6(6)−179.22(16)°. The distortion of
the coordination sphere around the “inorganic” Sn3 atoms is
reflected in equatorial or axial S−Sn−S angles of 85.03(6)−
In the crystal structures, two of the Sn atoms per inorganic
subunit bind to the organic ligands, whereas the third Sn atom
is exclusively coordinated by S2− ligands and is part of the
[Sn2S2] junction of the two subunits. Each Sn atom is
B
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123.29(7) and 178.30(6)°, respectively. The orientation of the
phenyl rings within each of the [Sn3S4] units allows for an
intramolecular T-shaped C−H···π interaction involving H10.
The packing of the molecules within the crystal (Figure S7 in
the Supporting Information) produces alternating layers that
comprise the inorganic parts of the clusters which are separated
by the aromatic rings, indicating further interactions between
the latter.
and the longest bonds are in positions cis to each other. Again,
Sn−C (2.179(7)−2.184(8) Å) and Sn−N distances vary only
slightly (2.367(7)−2.399(7) Å). A distortion of the trigonal-
bipyramidal coordination around the Sn atoms with Sn−C
bonds comes along with the “bite” of the atoms within the five-
membered Sn−C−C−C−N− ring (N−Sn−C 75.4(3),
75.9(3)°); equatorial atoms include angles of 100.1(2)−
128.9(2)° (C−Sn−S) and 90.85(8)−114.81(8)° (S−Sn−S),
and the “linear” groups show N−Sn−S angles in the range
174.38(16)−179.11(18)°. The SnS5 moieties exhibit S−Sn−S
angles of 85.90(7)−128.96(8)° (equatorial) or 175.46(7)°
(axial).
The 1-(naphthalen-1-yl)ethylidene)-decorated cluster in 7
(Figure 2) crystallizes with four formula units and six molecules
Both of the two naphthyl groups at one defect-heterocubane
unit, the planes of which include an angle of 45.16°, are
oriented toward the same neighboring molecule. This results in
self-complementary interactions between the respective ar-
omatics, similar to common C−H···π interactions except for an
unusual C−H−centroid angle. By continuation of the
interactions through the other [Sn3S4] moieties, one-dimen-
sional zigzag chains are generated (Figure 3). The distances
between the centroids of the six-membered rings and the H
atoms of the next naphthyl molecule are relatively short and
amount to 2.753 Å (A1···H) and 3.010 Å (A2···H).
The 2-(naphthalen-2-yl)ethylidene-substituted cluster was
obtained with only one CH2Cl2 molecule per formula unit (8·
CH2Cl2), which resulted in a crystal structure with the triclinic
space group P1 (Figure 4). Regarding the structural parameters
̅
observed in the molecular structure (Table S2 in the
Supporting Information), the deviation of the trans arrange-
ments from ideal 180° angles is even smaller than that in 7·
6CH2Cl2 (N1−Sn1−S4 177.66(9)°, N3−Sn2−S4 178.09(9)°,
S4−Sn3−S5 179.39(3)°), whereas angles among Sn, N, and C
atoms do not noticeably differ (C19−Sn2−N3 74.01(16)°,
C1−Sn1−N1 76.26(15)°). The Sn−S distances range between
2.3798(17) (Sn3−S5′) and 2.8891(14) Å (Sn3−S4). The
shortest and the longest Sn−S bonds are oriented cis at the
same Sn atom (Sn3−S5′, Sn3−S4).
Adjacent molecules are arranged in a way that the naphthyl
groups of one of the defect-heterocubane units of one cluster
point between two naphthyl groups of an adjacent defect-
heterocubane moiety from another cluster molecule. The
alternating stacking of the four aromatic groups affords two
nearly parallel orientations in the center with parallel-shifted
Figure 2. Molecular structure of the cluster in 7·6CH2Cl2. Thermal
ellipsoids are shown with 50% probability, organic moieties are shown
as wires, and H atoms are omitted for clarity. Atom color code: yellow,
S; gray, Sn; blue, N.
of CH2Cl2 per formula unit in the monoclinic space group C2/
c. The Sn−S distances (Table S2 in the Supporting
Information) vary between 2.390(2) Å (Sn3−S5) and
2.711(2) Å (Sn3−S4); thus, in agreement with 6, the shortest
Figure 3. Packing of the cluster molecules in 7·6CH2Cl2. Organic moieties are shown as wires, and most of the H atoms and solvent molecules are
omitted for clarity. Atom color code: yellow spheres, S; gray spheres, Sn; blue spheres, N; red spheres, H.
C
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Figure 4. Molecular structure of the cluster in 8·CH2Cl2. Thermal
ellipsoids are shown with 50% probability, organic moieties are shown
as wires, and H atoms are omitted for clarity. Atom color code: yellow,
S; gray, Sn; blue, N.
Figure 6. Molecular structure of the cluster in 10·2CH2Cl2. Thermal
ellipsoids are shown with 50% probability, organic moieties are shown
as wires, and H atoms are omitted for clarity. Atom color code: yellow,
S; gray, Sn; blue, N.
face-to-face π-stacking interaction and two inclined orientations
which resemble T-shaped π-stacking interactions (Figure 5).
The first produces short distances of the aryl centroids (3.954
Å) and an angle of 23.67° between the ring normal and
centroid contact axis. The H atom−centroid distances of the T-
shaped π-stacking interactions are also typical: 3.123−3.730
Å.16
2.425(4) and 2.448(4) Å, thus being longer and therefore
weaker than in the structures of 7 and 8. This is in agreement
with the different electronic properties of the aromatic systems,
which include an electronegative heteroatom in 10 that
withdraws electron density from the nearby azine group.
Similar to the crystal structures of 7 and 8, four aromatic
ligands from two [Sn3S4] subunits of two adjacent cluster
molecules are in close proximity, which reflects the similarities
of the architectures of the organic ligand shell. As in 8·CH2Cl2,
two quinolinyl fragments meet in the center of the four-
molecule arrangement in a parallel fashion, with an angle of
62.94° between their mean planes and those of the adjacent
quinolone units. However, the arrangement in 10·2CH2Cl2
only allows for the central, parallel-shifted face-to-face π-
stacking interaction to occur, whereas a T-shaped π-stacking
interaction with the outer ligand groups cannot be realized
(Figure 7). Both distances and angles between the centroids in
10·2CH2Cl2 correlate with characteristic interactions between
two quinolines that possess electron-withdrawing substituents
(Table 1).17
Our attempts to attach heteropolyaromatic groups to Sn/S
clusters were successful for the decoration of an [Sn6S10] cluster
with a quinolin-6-ylmethyl-terminated ligand. Compound 10·
2CH2Cl2 crystallizes in the triclinic space group P1. The
̅
molecular structure of the cluster molecule is shown in Figure
6.
Sn−S distances (Table S2 in the Supporting Information)
vary between 2.3830(12) Å (Sn3−S5) and 2.7276(12) Å
(Sn3−S4). According to the situation in 8·CH2Cl2, the shortest
and the longest Sn−S bonds share the same Sn atom. As usual,
the longest bond (Sn3−S4) is found between the “inorganic”
Sn atom (Sn3) and the μ3-bridging sulfide ligand. The average
Sn−(μ-S) bond length amounts to 2.41 Å, thus being situated
those found in 7·6CH2Cl2 and 8·CH2Cl2. Sn−C distances
(2.177(5) and 2.172(5) Å) and Sn−N distances (2.425(4) and
2.448(4) Å) are within the normal range. One observes a range
of “linear” ligand arrangements around the organyl-bound Sn
atoms (N1−Sn1−S4 178.09(10)°, N4−Sn2−S4 174.71(10)°)
similar to that in 7·6CH2Cl2. The intramolecular coordination
of the azine N atoms to the Sn atoms includes distances of
In the unit cells of 7·6CH2Cl2 and 10·2CH2Cl2 the cluster
arrangements lead to the generation of alternating layers of
Figure 5. Packing of the cluster molecules in 8·CH2Cl2. Organic moieties are shown as wires, and most of the H atoms and solvent molecules are
omitted for clarity. Atom color code: yellow spheres, S; gray spheres, Sn; blue spheres, N; red spheres, H.
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Figure 7. Packing of the cluster molecules in 10·2CH2Cl2. Organic moieties are shown as wires, and H atoms and solvent molecules are omitted for
clarity. Atom color code: yellow spheres, S; gray spheres, Sn; blue spheres, N; red spheres, H.
Table 1. Geometric Relations between the Ring Centroids or
EXPERIMENTAL SECTION
■
Ring Centroids and Adjacent H Atoms in 6, 7·6CH2Cl2, 8·
Syntheses. We describe herein a mild and straightforward method
to convert aromatic aldehydes or ketones to their hydrazine derivative
according to the following general procedure, which combined
methods reported previously by Lee18 and Wyles.19 Our approach
was similar to the synthesis procedure by Wyles and similar to the
workup procedure described by Lee: 20 mg of the substrate was
dissolved in 20 mL of ethanol. A ! mL portion of hydrazine hydrate
(80% in water) was added, and the mixture was heated to reflux for x
hours (for the value of x, see below). The solution was then stirred at
room temperature for 12 h and extracted several times with
chloroform to give a slightly yellow solution, until the chloroform
phase remained colorless. The organic phases were combined, dried
over MgSO4, filtered, and evaporated. The resulting residue was
analyzed by means of mass spectrometry and/or NMR spectroscopy.
Yields are 44−100% (see below). All molecules are depicted in
Scheme 2. New compounds are denoted by Arabic numbers.
a
CH2Cl2, and 9·2CH2Cl2
Compound 6
A1(A)···H10
A1(B)···H10
distance (Å)
2.991
12.17
3.345
12.09
α⊥ (deg)
Compound 7·6CH2Cl2
A1···H
A2···H
distance (Å)
2.753
8.14
3.010
12.89
α⊥ (deg)
Compound 8·CH2Cl2
A1···A3
A2···A4
A5···H18,H14
A6···H14
distance (Å)
3.954
22.06
3.954
25.85
3.123, 3.408
30.53, 14.52
3.730
28.35
α⊥ (deg)
Benzaldehyde Hydrazone. x = 1. Yield: 14 mg (1.21 × 10−4 mol,
1
Compound 10·2CH2Cl2
64%), yellow oil. H NMR (300.1 MHz, CDCl3): δ 8.68 (s, 1H),
A1···A3
A1···A4
A2···A3
A2···A4
7.90−7.81 (m, 2H). 7.50−7.44 (m, 3H), 5.54 (s, 2H, NH2) ppm.
1-Acetonaphthone Hydrazone. x = 2.5. Yield: 17 mg (9.28 × 10−5
distance (Å)
3.926
25.97
5.045
45.49
4.103
30.83
3.926
25.97
1
mol, 79%), yellow solid. H NMR (300.1 MHz, C7D8): δ 8.29−8.19
α⊥ (deg)
(m, 2H, E+Z), 7.63−7.55 (m, 1H, E+Z), 7.55−7.48 (m, 1H, E+Z),
7.34−7.13 (m, 4H, E+Z), 4.79 (s, 2H, NH2, E/Z), 4.49 (s, 2H, NH2,
E/Z), 2.18 (s, 3H, E/Z), 1.73 (s, 3H, E/Z) ppm. ESI+-MS: calculated
185.1073 [M + H]+, found 185.1077. The molecule shows E/Z
isomerism in solution, to be reflected in the NMR spectrum.
a
Distances are given between two ring centroids or between a ring
centroid and an H atom, respectively. α⊥ is defined as either the angle
between the ring normal of one ring and the centroid···centroid vector
including a second ring or the angle between the plane defined by a
ring and the corresponding H atom···ring centroid vector.
2-Acetonaphthone Hydrazone. x = 3. Yield: 9 mg (5.17 × 10−5
1
mol, 44%), yellow solid. H NMR (300.1 MHz, C7D8): δ 8.33−8.25
(m, 2H, E+Z), 8.17−8.10 (m, 2H, E+Z), 7.97−7.82 (m, 6H, E+Z),
7.62−7.49 (m, 2H, E+Z), 2.52 (s, 3H, E/Z), 2.47 (s, 3H, E/Z) ppm.
ESI+-MS: calculated 185.1073 [M + H]+, found 185.1070. The
molecule shows E/Z isomerism in solution, to be reflected in the
NMR spectrum.
inorganic and organic components of the molecules. The
solvent molecules are incorporated between the inorganic units.
Geometric relations between the ring centroids that are
involved in the diverse interactions in 7·6CH2Cl2, 8·CH2Cl2,
and 10·2CH2Cl2 are summarized in Table 1.
Quinoline-3-carbaldehyde Hydrazone. x = 4. Yield: 21 mg (1.27 ×
1
10−4 mol, quantitative), yellow solid. H NMR (300.1 MHz, CDCl3):
δ 9.20 (d, 1H, 3J = 1.89 Hz), 8.10 (d, 1H, 3J = 1.86 Hz), 8.08 (d, 1H, 2J
= 8.48 Hz), 7.86 (s, 1H), 7.78 (d, 1H, 2J = 7.95 Hz), 7.67 (ddd, 1H, 2J
CONCLUSION
2
= 7.67 Hz, 3J = 1.24 Hz), 7.52 (ddd, 1H, J = 7.46 Hz, 3J = 0.93 Hz),
■
5.76 (s, 2H, NH2) ppm. ESI+-MS: calculated 172.0869 [M + H]+,
found 172.0867.
A straightforward method for the conversion of diverse
aromatic molecules into their hydrazone derivatives was
found that does not require working under inert conditions.
The connection of the aromatic molecules with Sn/S clusters
was possible in all cases, which was proven by means of single-
crystal X-ray diffraction studies or by mass spectrometry. The
crystallization tendency of the ligand-decorated Sn/S clusters
seems to decrease with increasing size of the aromatic
molecules. In the crystal structures, polyaromatic ligands are
involved in notable intramolecular and intermolecular π-
stacking interactions, in agreement with the behavior of such
systems in other contexts. Future work will focus on the
interaction of metal atoms and ions with the aromatic rings.
Quinoline-6-carbaldehyd4 Hydrazone (1). x = 4. Yield: 21 mg
1
(1.27 × 10−4 mol, quantitative), yellow solid. H NMR (300.1 MHz,
CDCl3): δ 8.87 (dd, 1H, 2J = 4.30 Hz, 3J = 1.65 Hz), 8.12 (dd, 1H, 2J =
3
8.30 Hz, J = 1.46 Hz), 8.06 (s, 2H), 7.89 (s, 1H), 7.78 (s, 1H), 5.70
(s, 2H, NH2) ppm. ESI+-MS: calculated 172.0869 [M + H]+, found
172.0867.
3-Acetylquinoline Hydrazone (2). x = 4. Yield: 16 mg (8.64 × 10−5
mol, 74%) yellow solid. 1H NMR (300.1 MHz, CDCl3): δ 9.37 (d, 1H,
3J = 2.28 Hz), 8.18 (s, 1H), 8.10 (d, 1H, 2J = 8.49 Hz), 7.80 (d, 1H, 2J
= 8.13 Hz), 7.67 (dd, 1H, 2J = 7.55 Hz, 3J = 1.39 Hz), 7.52 (dd, 1H, 2J
= 7.46 Hz, 3J = 1.41 Hz), 5.50 (s, 2H, NH2), 2.21 (s, 3H) ppm. ESI+-
MS: calculated 186.1026 [M + H]+, found 186.1023.
E
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Scheme 2. Aromatic Hydrazones Derived from the Corresponding Aldehydes or Ketones
Scheme 3. Synthesis and Structure Diagram of [(R1Sn)4S6] (A; R1 = −CMe2CH2C(O)Me)
4-Acetylisoquinoline Hydrazone (3). x = 4. Yield: 21 mg (1.17 ×
Subsequent reactions of the hydrazones/hydrazines with A were
realized according to the following general procedure under strict
exclusion of external moisture and oxygen, using standard Schlenk-line
techniques or an Ar atmosphere with a glovebox: 1.0 equiv of A (30
mg, 2.82 × 10−5 mol) and 4.4 equiv of the corresponding hydrazone/
hydrazide were evacuated for 30 min and then flowed with argon and
suspended in 8 mL of CH2Cl2. The suspension was stirred for some
time x, filtered, and layered with solvent y. After a certain time z, the
solution and/or the crystals were analyzed via electrospray ionization
mass spectrometry (ESI-MS) and/or EDX and/or single crystal X-ray
diffraction (for x, y, and z, see below). Images of the high-resolution
mass spectra (HRMS) of those compounds that have not been
obtained as single crystals are given in the Supporting Information
(Figures S1−S6). Single-crystal yields amount to ca. 25−35% with
respect to the starting material, increasing with a decreasing number of
aromatic rings, as discussed below. The identity and purity of the bulk
material was confirmed via mass spectrometry. All NMR spectra
except that of compound 10were recorded on reaction solutions
due to the relatively low yields and poor solubility of the compounds;
therefore, a discrimination between the signals of defect-heterocubane
cluster cations and the doubly μ-S bridged “dimeric” clusters was not
possible; the 1H NMR spectra additionally show the signals of further
byproducts that could not be identified. Figure S8 in the Supporting
1
10−4 mol, quantitative), yellow solid. H NMR (300.1 MHz, CDCl3):
δ 9.18 (s, 1H), 8.49 (s, 1H), 8.23 (d, 1H, 2J = 8.40 Hz), 7.98 (d, 1H, 2J
= 8.07 Hz), 7.80−7.56 (m, 2H), 4.97 (s, 2H, NH2), 2.30 (s, 3H) ppm.
ESI+-MS: calculated 186.1026 [M + H]+, found 186.1025.
2-Acetylanthracene Hydrazone (4). x = 3. Yield: 11 mg (4.54 ×
1
10−5 mol, 50%), golden plates. H NMR (300.1 MHz, C7D8): δ 8.38
(dd, 1H, 2J = 9.09 Hz, 3J = 1.50 Hz), 8.09 (s, 1H), 8.04 (s, 1H), 7.80−
7.70 (m, 4H), 7.28−7.18 (m, 2H), 4.83 (s, 2H, NH2), 1.71 (s, 3H)
ppm. The molecule shows E/Z isomerism in solution, to be reflected
in the NMR spectrum. The signals of E and Z isomers are superposed
on each other in a way that inhibits a discrimination between E and Z
conformations.
2-Acetylphenanthrene Hydrazone (5). x = 3. Yield: 19 mg (8.26 ×
10−5 mol, 91%), cream-colored solid. 1H NMR (300.1 MHz, C7D8): δ
8.90−8.82 (m, 1H, E+Z), 8.60−8.54 (m, 1H, E+Z), 8.15−8.07 (m,
1H, E+Z), 7.66−7.56 (m, 2H, E+Z), 7.47−7.44 (m, 2H, E+Z), 7.43−
7.31 (m, 2H, E+Z), 4.83 (s, 2H, NH2, E+Z), 1.72 (s, 3H, E/Z), 1.71
(s, 3H, E/Z) ppm. The molecule shows E/Z isomerism in solution, to
be reflected in the NMR spectrum.
The organo-functionalized Sn/S cluster [(R1Sn)4S6] (A) was
prepared according to the literature procedure (see Scheme 3).4,5
F
DOI: 10.1021/acs.organomet.5b00295
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Organometallics
Article
1
Information shows the H and 119Sn NMR spectra of compound 10,
Supporting Information). Although the mass spectrum only shows the
[(C17H20N3Sn)3S4]+ species, we assume the formation of the quoted
cluster with two doubly μ-S bridged defect-heterocubane units as the
main product. This assumption is based on the fact that compounds
6−8 and 10 show the same behavior in ESI(+) mass spectrometry. 1H
NMR (300 MHz, CD2Cl2): δ 7.78−7.63 (m, HAr), 2.36 (s, 2H, CH2),
2.31 (s, 6H, CMe2), 2.16 (s, 3H, CMe), 1.96 (s, 3H, CMe) ppm. 119Sn
NMR (112 MHz, CD2Cl2): δ −61 ppm.
Synthesis of [(C14H9CMeNNCMeCH2CMe2)2Sn3S4(μ-S)]2 (13)
by Reaction of A with 2-Acetylanthracene Hydrazone (4). x, y, z: 1
day or 2 days, Et2O, EtOH, n-hexane, toluene, thf; no crystalline
products. MS (ESI+): m/z (%) 1215.3 (18), 1429.4 (100)
[(C22H23N2Sn)3S4]+. HRMS (ESI+): m/z calcd 1431.1544
[(C22H23N2Sn)3S4]+, found 1431.1514 (Figure S4 in the Supporting
Information). Although the mass spectrum only shows the
[(C22H23N2Sn)3S4]+ species, we assume the formation of the quoted
cluster with two doubly μ-S bridged defect-heterocubane units as the
main product. This assumption is based on the fact that compounds
6−8 and 10 show the same behavior in ESI(+) mass spectrometry. 1H
NMR (300 MHz, CD2Cl2): δ 8.71−7.53 (m, HAr), 2.78 (s, 2H, CH2),
2.16 (s, 3H, CMe), 2.14 (s, 3H, CMe), 1.91 (s, 6H, CMe) ppm. 119Sn
NMR (112 MHz, CD2Cl2): δ −62 ppm.
Synthesis of [(C14H9CMeNNCMeCH2CMe2)2Sn3S4(μ-S)]2 (14)
by Reaction of A with 2-Acetylphenanthrene Hydrazone (5). x, y, z:
1 day in the dark, Et2O, EtOH, n-hexane; no crystalline products. MS
(ESI+): m/z (%) 1215.4 (37), 1431.4 (100) [(C22H23N2Sn)3S4]+.
HRMS (ESI+): m/z calcd 1431.1541 [(C22H23N2Sn)3S4]+, found
1431.1498 (Figure S5 in the Supporting Information). Although the
mass spectrum only shows the [(C22H23N2Sn)3S4]+ species, we assume
the formation of the quoted cluster with two doubly μ-S bridged
defect-heterocubane units as the main product. This assumption is
based on the fact that compounds 6−8 and 10 show the same
behavior in ESI(+) mass spectrometry. 1H NMR (300 MHz, CD2Cl2):
δ 7.85−7.17 (m, 7H, HAr), 2.47 (s, 2H, CH2), 2.36 (s, 3H, Me), 2.15
(s, 3H, Me), 2.02 (s, 3H, Me), 1.83 (s, 3, Me) ppm. 119Sn NMR (112
MHz): δ −61 ppm.
which was measured on a solution of single crystals.
Synthesis of [(C6H5CHNNCMeCH2CMe2)2Sn3S4(μ-S)]2 (6) by
Reaction of A with Benzaldehyde Hydrazone. x, y, z: 2 days, n-
hexane, 6 weeks; colorless crystals. MS (ESI+): m/z (%) 1087.1 (32)
[(C13H17N2Sn)3S4]+; 1834.8 (16). HRMS (ESI+): m/z calcd
1089.0125 [(C13H17N2Sn)3S4]+, found 1089.0112. 1H NMR (300
MHz, CD2Cl2): δ 8.70 (1H, HAzine), 7.92−7.01 (m, 5H, HAr), 2.25−
2.12 (m, 2H, CH2), 1.41 (s, 6H, CMe2), 1.34 (s, 3H, CMe) ppm. 119Sn
NMR (112 MHz): δ −48, −75 ppm.
Synthesis of [(C10H7CMeNNCMeCH2CMe2)2Sn3S4(μ-S)]2··
6CH2Cl2 (7·6CH2Cl2) by Reaction of A with 1-Acetonaphthone
Hydrazone. x, y,z: 8 days, Et2O, 3 weeks; colorless crystals. MS
(ESI+): m/z (%) 1281.3 (100) [(C18H21N2Sn)3S4]+. HRMS (ESI+):
m/z calcd 1279.1065 [(C18H21N2Sn)3S4]+; found 1279.1063. 1H NMR
(300 MHz, CD2Cl2): δ 8.00−7.00 (m, 7H, HAr), 2.87 (s, 2H, CH2),
2.39 (s, 3H, CMe), 2.29 (s, 6H, CMe2) ppm. 119Sn NMR (112 MHz):
δ −63, −87 ppm.
Synthesis of [(C10H7CMeNNCMeCH2CMe2)2Sn3S4(μ-S)]2·
CH2Cl2 (8·CH2Cl2) by Reaction of A with 2-Acetonaphthone
Hydrazone. x, y, z: 2 days, toluene, 3 weeks; colorless crystals. MS
(ESI+): m/z (%) 963.3 (49), 999.6 (8), 1077.6 (33), 1528.0 (29).
None of the signals concur with the structure that was verified by
single-crystal X-ray diffraction. This indicates decomposition either in
solution or under the measurement conditions. EDX: Sn/S calcd 6:10,
1
found 5.55:10. H NMR (300 MHz, CD2Cl2): δ 7.97−7.79 (m, 5 H,
HAr), 7.63−7.45 (m, 3H, HAr), 2.53 (s, 2H, CH2), 2.38 (s, 3H, Me),
2.26 (s, 6H, CMe2), 2.15 (s, 3H, Me) ppm. 119Sn NMR (112 MHz): δ
−67 ppm.
Synthesis of [(C9H8CMeNNCMeCH2CMe2)2Sn3S4(μ-S)]2 (9) by
Reaction of A with 3-Quinolinecarbaldehyde Hydrazone. x, y, z: 4
days, Et2O, toluene, n-hexane; no crystalline products. MS (ESI+): m/z
(%) 438.2 (25), 841.2 (5), 962.1 (10), 1101.2 (30), 1240.2 (77)
[(C16H18N3Sn)3S4]+; 1676.5 (8). HRMS (ESI+): m/z calcd 1240.0451
[(C16H18N3Sn)3S4]+, found 1240.0446 (Figure S1 in the Supporting
Information). Although the mass spectrum only shows the
[(C16H18N3Sn)3S4]+ species, we assume the formation of the quoted
cluster with two doubly μ-S bridged defect-heterocubane units as the
main product. This assumption is based on the fact that compounds
6−8 and 10 show the same behavior in ESI(+) mass spectrometry. 1H
NMR (300 MHz, CD2Cl2): δ 8.16−7.55 (m, HAr), 2.31−2.26 (m, 8H,
CH2, CMe2), 2.20 (3H, CMe), 2.10 (3H, CMe) ppm. 119Sn NMR
(112 MHz, CD2Cl2): δ −72 ppm.
Synthesis of [(C10H7NHNCMeCH2CMe2)2Sn3S4(μ-S)]2 (15) by
Reaction of A with 1-Naphthylhydrazine. A 0.17 mmol portion of 1-
naphthylhydrazine hydrochloride was suspended in 5 mL of water, and
a saturated solution of sodium hydrogen carbonate was added until the
suspension became basic. Solvent was then removed in vacuo, and the
resulting residue was dried for 30 min under vacuum. It was dissolved
in 7 mL of CH2Cl2 and a solution of 0.038 mmol of A in 4 mL of
CH2Cl2 was added. Filtration after 6 days and subsequent layering
with toluene or thf, respectively, did not yield crystalline products. MS
(ESI+): m/z (%) 541.1 (13), 671.2 (13), 722.8 (15), 822.9 (10), 964.9
(10), 1061.1 (36), 1201.1 (100) [(C16H20N2Sn)3S4]+. HRMS (ESI+):
m/z calcd 1201.0594 [(C16H20N2Sn)3S4]+, found 1201.0616 (Figure
S6 in the Supporting Information). Although the mass spectrum only
shows the [(C16H20N2Sn)3S4]+ species, we assume the formation of
the quoted cluster with two doubly μ-S bridged defect-heterocubane
units as the main product. This assumption is based on the fact that
compounds 6−8 and 10 show the same behavior in ESI(+) mass
Synthesis of [(C9H8NCHNNCMeCH2CMe2)2Sn3S4(μ-S)]2·
2CH2Cl2 (10·2CH2Cl2) by Reaction of A with 6-Quinolinecarbalde-
hyde Hydrazone (1). x, y, z: 4 days, Et2O, 2 weeks; red crystals. MS
(ESI+): m/z (%) 438.2 (28), 839.2 (5), 1087.2 (8), 1240.3 (77)
[(C16H18N3Sn)3S4]+. HRMS (ESI+): m/z calcd 1240.0451
[(C16H18N3Sn)3S4]+, found 1240.0453. 1H NMR (300 MHz,
CD2Cl2): δ 9.51 (s, 1H, HHydrazone), 8.26−7.15 (m, HAr), 2.77 (s,
2H, CH2), 2.29 (s, 3H, CMe), 1.50 (s, 6H, CMe2) ppm (Figure S8, top,
in the Supporting Information). 119Sn NMR (112 MHz, CD2Cl2): δ
−48, −73 ppm (Figure S8, bottom).
Synthesis of [(C9H6NCMeNNCMeCH2CMe2)2Sn3S4(μ-S)]2 (11)
by Reaction of A with 3-Acetylquinoline Hydrazone (2). x, y, z: 5
days, toluene, thf, Et2O; no crystalline products. MS (ESI+): m/z (%)
1282.5 (100) [(C17H20N3Sn)3S4]+. HRMS (ESI+): m/z calcd
1282.0918 [(C17H20N3Sn)3S4]+, found 1282.0918 (Figure S2 in the
Supporting Information). Although the mass spectrum only shows the
[(C17H20N3Sn)3S4]+ species, we assume the formation of the quoted
cluster with two doubly μ-S bridged defect-heterocubane units as the
main product. This assumption is based on the fact that compounds
6−8 and 10 show the same behavior in ESI(+) mass spectrometry. 1H
NMR (300 MHz, CD2Cl2): δ 8.09−7.52 (m, HAr), 2.39 (s, 2H, CH2),
2.25 (s, 6H, CMe2), 2.16 (s, 3H, CMe), 1.94 (s, 3H, CMe) ppm. 119Sn
NMR (112 MHz, CD2Cl2): δ −58 ppm.
1
spectrometry. H NMR (300 MHz, CD2Cl2): δ 7.90−7.72 (m, 3H,
HAr), 7.52−7.27 (m, 4H, HAr), 2.88 (s, 2H, CH2), 1.89 (s, 3H, Me),
1.81 (s, 3H, Me) ppm. 119Sn NMR (112 MHz): δ −69, −81 ppm.
Single-Crystal X-ray Diffraction Analyses. Data were collected
on a diffractometer equipped with an STOE imaging plate detector
system IPDS2 or 2T or a Bruker D8 Quest instrument, using Mo Kα
radiation with graphite monochromatization (λ 0.71073 Å) at 100 K.
The structure solution was performed using direct methods, full-matrix
least-squares refinement against F2, with SHELXTL software and the
OLEX2 software package.20,21 Details of the data collections and
refinements are given in Table S1 (see the Supporting Inforamtion).
Structural data of all compounds are summarized in Table S2 (see the
Supporting Inforamtion).
Synthesis of [(C9H6NCMeNNCMeCH2CMe2)2Sn3S4(μ-S)]2 (12)
by Reaction of A with 4-Acetylisoquinoline Hydrazone (3). x, y, z: 1
day, Et2O, EtOH, n-hexane; no crystalline products. MS (ESI+): m/z
(%) 1284.2 (100) [(C17H20N3Sn)3S4]+. HRMS (ESI+): m/z calcd
1282.0918 [(C17H20N3Sn)3S4]+, found 1282.0929 (Figure S3 in the
Spectroscopy and Spectrometry. 1H NMR, 13C NMR, and
119Sn NMR measurements were carried out using Bruker DRX 300
1
and 400 MHz spectrometers at 25 °C. In H and 13C NMR spectra,
chemical shifts are quoted in ppm relative to the residual protons of
G
DOI: 10.1021/acs.organomet.5b00295
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
deuterated solvents. For 119Sn NMR measurements, Me4Sn was used
as an internal standard. Mass spectrometry (MS) was performed on a
Finnigan MAT 95S isntrument. Electrospray ionization mass
spectrometry (ESI-MS) was performed on a Finnigan LTQ-FT
spectrometer by Thermo Fischer Scientific in the positive ion mode
with solvent as carrier gas. EDX analysis was performed using the EDX
device Voyager 4.0 of Noran Instruments coupled with a CamScan CS
4DV electron microscope. Data acquisition was performed with an
acceleration voltage of 20 kV and 100 s accumulation time. For the
analysis, multiple single crystals were used and the data were recorded
for both various times on a single crystal and various times on other
single crystals.
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* Supporting Information
Figures, tables, and CIF files giving mass spectra and structure
diagrams of compounds 9 and 11−15 and crystallographic
tables and a supplementary crystallographic figure. The
Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.organo-
met.5b00295.
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AUTHOR INFORMATION
■
Corresponding Author
*S.D.: fax, +49 6421 2825653; tel, +49 6421 2825751; e-mail,
dehnen@chemie.uni-marburg.de.
Notes
Organomet. Chem. 2012, 26, 471−477. (d) Novak
́
, M.; Dostal
́
, L.;
The authors declare no competing financial interest.
Ruzick
a, A.; Jambor, R. Inorg. Chim. Acta 2014, 410, 20−28.
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Dehnen, S. Chem. - Eur. J. 2009, 15, 6595−6604.
ACKNOWLEDGMENTS
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This work was supported by the Deutsche Forschungsgemein-
schaft (DFG) within the framework of GRK1782. We thank
Jan Christmann for his help with the syntheses and NMR
spectroscopic characterization of the title compounds.
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