Oxidative Addition to SnII Guanidinate Complexes: Precursors to Tin(II) Chalcogenide Nanocrystals

Article abstract of DOI:10.1002/ejic.201800071

SnS, SnSe and SnTe are potentially important semiconductor materials. Here, we describe the application of chalcogen containing Sn^IV guanidinate precursors for the production of tin(II) chalcogenide nanocrystals. Reaction of the stannylene(II)

Full text of DOI:10.1002/ejic.201800071

A Journal of
Accepted Article
Title: Oxidative Addition to Sn(II) Guanidinate Complexes: Precursors
to Tin(II) Chalcogenide Nanocrystals .
Authors: Andrew Lee Johnson, Ibrahim Y. Ahmet, and Joseph
Thompson
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10.1002/ejic.201800071
European Journal of Inorganic Chemistry
FULL PAPER
Oxidative Addition to Sn(II) Guanidinate Complexes: Precursors
to Tin(II) Chalcogenide Nanocrystals.
Ibrahim. Y. Ahmet,[a] [b] Joseph R. Thompson, [a] [b] and Andrew. L. Johnson *[a]
Abstract: SnS, SnSe and SnTe are
a
potentially important
crystallinity of the materials i.e. thin films vs nanocrystals, size and
surface quality.[3]
semiconductor materials. Here, we described the application of
chalcogen containing Sn(IV) guanidinate precursors, for the
production of tin(II) chalcogenide nano-crystals. Reaction of the
stannylene (II) guanidinate complex [{Me2NC(NCy)2}2Sn] (1) with
Ph2E2 (E = S, Se, Te), and CBr4 forms the Sn(IV) complexes
[{Me2NC(NCy)2}2Sn(Ch-Ph)2] (2-4) and [{Me2NC(NCy)2}2SnBr2] (5)
respectively. Complex 5 has been subsequently used for the
Over the past two decades research has shown unmistakably,
that the most relevant aspect to controlling the morphology of both
thin films and nanocrystals is the precise selection of starting
molecular precursors,[4] and it is this choice of precursor which
determines features such as reaction solvent/temperature, and in
the case of nanocrystal/thin film formation deposition/production
synthesis of the corresponding Sn(IV) mono chalcogenide complexes, temperatures.[5]
[{Me2NC(NCy)2}2Sn=E] (6-8) by the reaction of 5 with Li2E systems.
Isolated tin complexes have characterized by elemental analysis,
NMR spectroscopy, and the molecular structures of complexes 2-5
determined by single crystal X-ray diffraction. TG analysis showed
complexes 2-4 and 6-8 all to have residual masses close to those
expected for the formation of the corresponding ‘SnE’ systems.
Complexes 6-8 were assessed for their utility in the formation of nano-
crystalline materials. The materials obtained were characterized by
powder X-ray diffraction (XRD), field emission scanning electron
microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX).
Analysis showed formation of SnSe and SnTe from complexes 7 and
8, respectively.
Lewis et al. have recently reviewed routes to both thin film and
nanoparticle of IV-VI chalcogenide materials.[1c] A key feature in
the development of successful precursors for Sn(II) chalcogenide
materials is the ability to control the oxidation state of the tin
during the deposition process, so as to suppress the production
of materials with variable oxidation states (i.e. Sn2S3 SnS2,
Sn2Se3 and SnSe2) the presence of which can be detrimental to
6]
the performance binary Sn(II) chalcogenide materials.[1c,
Therefore the ability to control the formation of these materials is
paramount and to this end a large number of ligand systems have
been developed in an attempt to do so.
As part of an ongoing exploration into the chemistry of group 14
systems and their application in the formation of IV:VI
semiconducting materials, such as SnS and SnO,[6-7] we have
previously reported the chemistry of the homoleptic Sn(II)
guanidinate system [{Me2NC(NCy)2}2Sn] (1). Complex 1, readily
formed in quantitative yields by the insertion of dicyclohexyl-
carbodiimide into the {Sn-NMe2} bonds of [Sn(NMe2)2] (Scheme
1), has proved to be an intriguing departure point for the synthesis
of a range of Sn(IV) guanidinate complexes by reaction with
elemental chalcogens (S, Se and Te) as well as single atom
chalcogen transfer reagents such as (tBu)3P=Te,[8] Et3PSe[9] and
styrene sulfide,[10] forming of a range of mono and poly
Introduction
The family of IV-VI mono-chalcogenide semiconducting materials,
and in particular SnS, SnSe and SnTe, have attracted significant
attention over the past decade.[1] The mono-chalcogenides ‘SnE’
(E = S, Se and Te) all display intense absorption across the
electromagnetic spectrum, with narrow band gaps (E = S, 1.1 eV
(direct), 1.3 eV (indirect); E = Se, 0.9 eV (direct), 1.3 eV (indirect);
E = Te, 0.18 eV),[2] and therefore have potential as materials for
thermoelectric devices, field effect transistors, superconducting
crystals, rechargeable batteries, solar cells and near infrared
detectors2015. Significant properties such as charge transfer and
charge transport depends strongly on the morphology and
chalcogenide
systems
of
the
general
form
[{Me2NC(NCy)2}2Sn(Ex)] (E = S or Se; X =1 or 4; Ch = Te, X = 1).
While selected tin chalcogen products have found utility in AA-
CVD of Sn, SnS, SnSe and SnTe thin films,[11] the product
distribution form direct reaction between stannylenes and
elemental chalcogens are difficult to control and reaction with
single atom transfer reagents, such as Et3PSe, often results in
contamination with phosphine by-products.[7d]
[a]
[b]
Centre for Sustainable Chemical Technologies
Department of Chemistry,
University of Bath. Claverton Down, Bath, BA2 7AY, UK.
Department of Chemistry,
University of Bath.
Claverton Down,
Bath, BA2 7AY, UK
E-mail: a.l.johnson@bath.ac.uk
Supporting information for this article is given via a link at the end of
the document.
Scheme 1. Synthesis of the homoleptic Sn(II) Guanidinate complexes 1.
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10.1002/ejic.201800071
European Journal of Inorganic Chemistry
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In these systems, the unprecedented oxidative control over the
resulting thermal decomposition products is such that we have
been able to show selective, and exclusive, formation of thin films
of Sn, SnS, SnSe and SnTe from an isoreticular series of
complexes.
stereo-active lone pair of the stannylene, and formation of the
Sn(IV) bis-phenylchalcogenide complexes, 2-3 as shown in
Scheme 2.
Results and Discussion
Reaction of di-cyclohexylcarbodiimide, in THF, with Sn(NMe2)2 in
2:1 molar ratio readily affords the homoleptic stannylene complex
[{Me2NC(NCy)2}2Sn] (1). Similar stannylenes have been reported
previously.[12] For the purposes of reference, and relevant to our
discussion, the molecular structure of complex 1 has been
reproduced here and is shown in Figure 1. Complex 1 has
Scheme 2. Synthesis of the Sn(IV) bis-Guanidinate bis-phenylchalcogenide
complexes 2-3.
previously been fully characterized by solution state NMR (1H, 13
C
Progress of the reaction could be easily followed since a color
changes from yellow to colorless (2), yellow to orange (3) and
yellow to red (4), respectively were clearly observable. The
resulting products were isolated in high yields (63%-89%). 1H and
13C NMR spectra of the resulting products showed the presence
two resonances associated with the {CH} moieties of the bis-
cyclohexyl guanidinate ligand, indicating a degree of asymmetry
in the products. An inspection of the 1H NMR spectra for 2-4
indicates a 1:1 ratio of the {Me2NC(NCy)2} ligands and {Ph}
groups indicative of the formation of complexes of the general
form [{Me2NC(NCy)2}2Sn(E-Ph)2]. This asymmetry is further
confirmed with the presence of 12 resonances associated with the
{CH} and {CH2} groups on the bis-cyclohexyl guanidinate ligand
in the 13C NMR spectra for 2-4. 119Sn NMR spectra for complexes
2 and 3 show the presence of single resonances for each of the
complexes at  = -578 ppm (2) and -742 ppm (3), with additional
coupling to the selenium atoms in complex 3 [1JSnSe = 1410 Hz].
Not unsurprisingly, the 77Se NMR spectrum for 3 shows the
presence of singlet resonance [δSe = 267 ppm] accompanied by
satellites generated by coupling to the neighbouring 119Sn centre
[1JSeSn 1411 Hz]. Unfortunately, intensive investigation of
compound 4 by 119Sn and 125Te NMR spectroscopy failed to
reveal the anticipated Sn and Te resonances.
and 119Sn) spectroscopy and elemental analysis. 119Sn NMR
spectra of 1 shows the presence of a single resonance at  = -
380.9 ppm.
Figure 1. Two views of the molecular structure of the bis-guanidinate
stannylene complex 1. Hydrogen atoms have been full omitted, and the
cyclohexyl groups have been partially omitted for clarity.
Subsequent reaction of 1 at ambient temperature, with the
diphenyl dichalcogenide reagents Ph2E2 (E = S, Se and Te)
results in the rapid oxidative addition of the {E-E} bond across the
Figure 2. Molecular structure of the Sn(IV) bis-phenylchalcogenide complexes 2-4. Hydrogen atoms have been full omitted, and the cyclohexyl groups have been
partially omitted for clarity. Disorder in the {Ph} and [13] groups of complex 4 have also been omitted for clarity.
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10.1002/ejic.201800071
European Journal of Inorganic Chemistry
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Table 1. Selected bond distances (Å) and angles (o) for 1-4
Sn-N
Sn-E
N-Sn-N
E-Sn-E
1a
2b
3b
4b
Sn(1)-N(11) 2.4149(12)
Sn(1)-N(21) 2.4258(12)
N(11)-Sn(1)-N(21) 138.39(4)
N(12)-Sn(1)-N(22) 102.54(5)
Sn(1)-N(12) 2.1780(12)
Sn(1)-N(11) 2.1895(12)
N(11)-Sn(1)-N(22) 96.83(4)
N(12)-Sn(1)-N(21) 93.15(4)
N(11)-Sn(1)-N(12) 58.03(4)
N(21)-Sn(1)-N(22) 57.86(4)
Sn(1)-N(22) 2.1686(12)
Sn(1)-N(12) 2.1875(12)
Sn(1)-S(2) 2.4859(4)
Sn(1)-S(1) 2.5070(4)
N(12)-Sn(1)-N(22) 157.80(5)
N(11)-Sn(1)-N(21) 89.33(4)
S(1)-Sn(1)-S(2) 95.368(13)
Sn(1)-N(11) 2.2307(12)
Sn(1)-N(21) 2.2353(12)
N(11)-Sn(1)-N(22) 107.40(5)
N(12)-Sn(1)-N(21) 99.01(4)
N(11)-Sn(1)-N(12) 60.78(4)
N(21)-Sn(1)-N(22) 60.56(4)
Sn(1)-N(11) 2.188(12)
Sn(1)-N(22) 2.180(12)
Sn(1)-Se(2) 2.625(4)
Sn(1)-Se(1) 2.644(4)
N(11)-Sn(1)-N(22) 146.40(5)
N(12)-Sn(1)-N(21) 94.03(4)
Se(1)-Sn(1)-Se(2) 94.24(13)
Sn(1)-N(12) 2.243(12)
Sn(1)-N(21) 2.236(12)
N(11)-Sn(1)-N(21) 95.92(5)
N(12)-Sn(1)-N(21) 95.54(4)
N(11)-Sn(1)-N(12) 60.28(4)
N(21)-Sn(1)-N(22) 60.52(4)
Sn(1)-N(11) 2.189(12)
Sn(1)-N(22) 2.201(12)
Sn(1)-Te(2) 2.832(4)
Sn(1)-Te(1) 2.845(4)
N(11)-Sn(1)-N(22) 143.77(5)
N(12)-Sn(1)-N(21) 95.54(4)
Te(1)-Sn(1)-Te(2) 95.33(13)
Sn(1)-N(12) 2.268(12)
Sn(1)-N(21) 2.204(12)
N(11)-Sn(1)-N(21) 93.86(5)
N(12)-Sn(1)-N(21) 94.74(4)
N(11)-Sn(1)-N(12) 60.01(4)
N(21)-Sn(1)-N(22) 60.40(4)
[a] taken from [14]. [b] This work.
Elemental analysis of the complexes similarly suggest the
formation of the expected Sn(IV) bis-phenylchalcogenide
complexes. Single crystals, suitable for X-ray diffraction studies,
of complexes 2-3 were obtained upon storage of concentrated
hexane solutions at -28 oC for 12 to 24 hrs. While all three
complexes are fundamentally isostructural, complex 2 crystallises
in the monoclinic space group P21/n with one full molecule in the
asymmetric unit, whereas complexes 3 and 4 crystallise in the
triclinic space group P-1 again with one molecule per asymmetric
unit. The molecular structures for the three complexes are shown
in figure 2. Selected bond lengths and angles are provided in table
1.
As noted previously, all three complexes, 2-4, are isostructural,
with analogous gross structural features, i.e. the presence of a
central hexa-coordinated pseudo-octahedral Sn atom, with the
two phenyl chalcodenide groups occupying cisoidal equatorial
positions. The remaining four coordination sites are occupied by
the nitrogen atoms of the two bi-dentate guanidinate ligands
which occupy equatorial and axial coordination site. The
differences between the three structures therefore lie in the
relative orientation of the phenyl chalcogenide substituents as
well as the relative orientation of both the cyclohexyl derivatives
and the {NMe2}, moieties. Inspection of the complexes reveal Sn-
N bond lengths in 2-4 are comparable with related Sn(IV)
guanidinate and amidinate complexes in the literature.[10, 15] In all
three complexes there is a slight lengthening of the axial and
equatorial Sn-N bonds as the atomic number of the chalcogen
atom attached the tin centre increases. The significant contraction
of the axial Sn-N bonds, in 1, upon oxidation [ave. ~2.42Å to 2.17-
2.19 Å] we presume is due the change in oxidation state of the
central tin atom.
Perhaps not unsurprisingly, the average Sn-E bond length
increase with the increasing atomic number of the chaclogen
atom, and are in good agreement with both comparable Sn-E
single bonds within the Cambridge Structural Database (CSD),
specifically the related aryl and alkyl-halcogenane compounds
such as [{(Me3Si)2N}2Sn(E-Ph)2][7d] and [{(Me3Si)2N}2Sn(E-Et)2][16]
as well as theoretical values for single bonds calculated from the
sum of the single bond covalent radii.[17]
Table 2. Selected distances (Å) and angles (o) for 2-4

 [E···E]
2
3
4
95.97° 85.65° 3.692 Å
94.24° 86.32° 3.861 Å
95.32° 85.57° 4.196 Å
Ch
Ch
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10.1002/ejic.201800071
European Journal of Inorganic Chemistry
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Despite the increase in steric demands of the {E-Ph} groups in 2-
4 respectively, which is reflected in the lengthening of the Sn-E
bonds, there no accompanying change in the {E-Sn-E} angle ()
or the interplanar {N2Sn} x {SnN2} angles ()[15b] (see table 2), (Cf.
interplanar angles observed in 1 [108.25°]). Although there is a
general increase in the [E···E] distance. By the same token, the
bite angle of the guanidinate ligands remain similar throughout [2:
ave. 60.68°, 3: ave. 60.40°, 4: ave. 60.2°]. One striking feature is
the increasing deviation away from linearity of the axial N-Sn-N
angle from 157.8° (2), to 146.4° (3) and 143.8° (4), respectively,
as the cisoidal chalcogen atoms increase in size.
As part of our study we also wished to investigate an alternative
route to the mono-chalcogenide products [{Me2NC(NCy)2}2Sn=E]
(E = S, Se or Te). We have previously described the synthesis of
these complexes via the direct reaction of the stannylene 1 with
suitable single chalcogen atom transfer reagents. However, we
wished to improve the synthetic route by investigating the
reactivity of dihalo-Sn(IV) guanidinate complexes with Li2E (E = S,
Se and Te). Reaction of the stannylene 1 with CBr4 results in the
clean oxidation of the Sn(II) center and formation of the di-bromo
Sn(IV) complex 5 (Scheme 3). Similar reactivity has been
observed with plumbylene systems,[18] although this is, we believe,
the first reported example of the reaction of CBr4 with a stannylene.
Figure 3. Molecular structure of the Sn(IV) dibromo bis-guanidinate complex 5.
Hydrogen atoms have been full omitted, and the cyclohexyl groups have been
partially omitted for clarity. Selected bond lengths (Å) and selected bond angles
(°): Sn(1)-Br(1) 2.5696(8), Sn(1)-Br(2) 2.5702(9), Sn(1)-N(11) 2.140(6), Sn(1)-
N(22) 2.167(5), Sn(1)-N(12) 2.206(6), Sn(1)-N(21) 2.192(6); Br(1)-Sn(1)-Br(2)
92.74(3), N(11)-Sn(1)-N(22) 152.6(2), N(12)-Sn(1)-N(21) 96.7(2), N(11)-Sn(1)-
N(12) 61.8(2), N(21)-Sn(1)-N(22) 61.7(2).
The Sn-N bond lengths are again comparable with other Sn(IV)
bis-guanidinate systems described ibid. Similarly, the interatomic
Sn-Br distances are comparable to the only other bis-guanidinate
stannene system containing a Sn-Br interaction reported in the
literature.[20] In contrast to the [E-Sn-E] angles in complexes 2-4,
the Br-Sn-Br angle in 5 is notably smaller. Concomitantly, the
interplanar {N2Sn} x {SnN2} angle [ = 84.3°] only slightly smaller
than that observed in complexes 2-4.
Scheme 3. Synthesis of the Sn(IV) bis-Guanidinate di-bromo complexes 5.
Reaction of 1 with equimolar amounts of CBr4, in THF, results in
an immediate color change from pale yellow to red/purple.
Removal of the solvent followed by recrystallisation from toluene
results in formation of red crystals of 5 in almost quantitative yield
(98%). The precise mechanism by which CBr4 reacts with the
stannylene 1 is unknown. However, it is most probable that the
mechanism is comparable to similar reactions between
stannylenes and alkyl halides,[19] with initial insertion across the
Br-C bond, followed by elimination of a putative {CBr2} fragment.
As anticipated, 1H and 13C NMR spectra of complex 5 reveal the
presence of resonances associated with both the cyclohexyl {CH}
and {NMe2} groups [1H  = 3.30 {C(H)}, 3.45 {C(H)} and 2.44 ppm
{NMe2}]. The 119Sn NMR spectrum for 5 shows the presence of a
single resonance at  = -567 ppm, which is comparable to related
Sn(IV) di-haogen systems in the literature.[15c] Elemental analysis
of 5 closely matched the predicted carbon, nitrogen and hydrogen
percentage masses expected for the complex. Figure 3 shows the
molecular structure of complex 5, with selected bond lengths and
angles reported in the figure caption. Crystallising in the
monoclinic space group P21, complex 5 is a C2 symmetric
dibromo-stannene at the centre of which resides a six-coordinate
tin atom with a distorted pseudo octahedral geometry (Br(1), Br(2),
N(12) and N(21) atoms in equatorial positions).
Direct reaction of 5 with either Li2S, Li2Se or Li2Te (made in-situ
in THF from elemental chalcogens and the super hydride,
Li[BEt3H]),[21] (Scheme 4), resulted in the formation of the
corresponding mono-chalcogenide complexes, which after
extraction away from THF and LiBr, could be isolated as
microcrystalline powders in higher yields [6: 81%, 7: 96%. 8: 92%]
than corresponding reaction between the stannylene 1, and
suitable chalcogenide transfer reagents mentioned previously.[11]
The reactions of 5 with the dilithio-chalcogenides resulted in
obvious colour changes from a brown/red solution (5) to a pale
yellow (6) and orange solution (7), respectively, alongside the
formation of a cream coloured suspension.
Scheme 4. Salt metathesis synthesis of the Sn(IV) bis-Guanidinate mono-
chalcogenide complexes 6-8.
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10.1002/ejic.201800071
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For complex 8, very little colour change was observed and the
reaction was worked-up after a 48hr.
residues of 24.2% formed around 348 °C which corresponds
directly to the mass residue expected for the formation of
In all cases, characterisation data (1H, 13C and 119Sn NMR
spectroscopy and elemental analysis) for complexes 6-8 was
identical to that previously reported for these complexes.[11]
SnTe. Contrastingly, the mono-chalcogen derivatives
6, 7
and all show multi-step decomposition pathways (Fig. 4B)
8
over differing temperature ranges. However, in all three
cases the final mass residue is found to be less than that
expected, respectively, for “SnS”, “SnSe” or “SnTe”
formation, possibly indicating a small degree of volatility. It
should be noted, however, that the solid state decomposition
process monitored in thermogravimetric analysis is probably
very different to any solvothermal decomposition process,
and can only be used as a general guide.
(A)
100
2
70
3
4
Table 3: Expected
% residue, % of non-volatile residue and onset of
volatilisation/decomposition temperature for 2-4 and 6-8.
40
Precursor
Expected % for Residue
(Residue)
% Non-volatile
Residue
Onset
Temp.§
Melting
point
10
(Temp.)
50
150
250
350
450
Temperature C
2
3
4
6
7
8
18.1 (SnS) 21.9 (SnS2)
21.4 (SnSe) 29.9 (SnSe2)
24.2 (SnTe)
25.1 (405 °C)
25.5 (348 °C)
24.2 (289 °C)
18.6 (349 °C)
27.6 (248 °C)
28.3 (248 °C)
157 °C
157 °C
124 °C
121 °C
201 °C
150 °C
133 °C
155 °C
140 °C
149 °C
115 °C
101 °C
(B)
100
70
23.1 (SnS)
28.3 (SnSe)
6
7
8
33.2 (SnTe)
Tin Chalcogenide Nanocrystals
40
In a typical procedure for the preparation of tin chalcogenide
nanocrystals, the precursor was dissolved in a minimum volume
of hexane. To this solution oleylamine was added and the hexane
was removed in vacuo. The reaction mixture was then heated at
210 °C for 40 min before being cooled to room temperature.
Excess ethanol was added and the precipitate was collected by
ethanol washing and centrifugation three times.
10
50
150
250
350
450
Temperature C
Figure 4. Thermogravimetric analysis data for complexes (A) 2-4 and (B) 6-8.
Thermogravimetric analyses (TGA) of complexes 2-4 and
6-8 were performed in order to gain insight into relative
volatilities and thermal stabilities of the compounds (Figure
4). Table 3 gathers relevant data, relating to %-mass
residues, expected %-mass residues, onset temperatures
and melting points for these complexes. Analyses were
carried out with an instrument housed in a nitrogen filled
purge-box in order to minimize reaction with atmospheric
moisture/air.
B
A
200 nm
200 nm
200 nm
Compounds 2-4 (Figure 4A) were found to undergo mass
loss to yield stable residues of between 24-25.5 % over the
C
temperature range 289-405 °C. In the case of complex
2 and
3
respectively, the % mass of the non-volatile residues,
25.1% and 25.5%, are both higher than residual masses
expected for the formation of the appropriate mono-
chalcogenide (i.e. 18.1% for SnS and 21.4% for SnSe).
However, It should be noted that the formation of the
corresponding di-chalcogenide systems SnS2 (21.9%) and
SnSe2 (29.94%) cannot be ruled out in these systems. In the
case of complex 4 the TGA trace reveals a significantly
cleaner single decomposition process with a stable %mass
Figure 5. TEM images of nano-crystal synthesised from A – 6, B - 7 and C - 8.
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The tin chalcogenide precursors 2–4 and 6–8, were used in
the nanocrystal preparation procedure with varying degrees of
success: Compounds 2-4 failed to make identifiable chalcogenide
containing materials.
While EDX analysis of the materials isolated did show the
presence of Sn & S, Sn & Se and Sn & Te respectively, all the
materials were Sn rich and contained a high carbon content
consistent with an incomplete decomposition and formation of the
desired materials. Analysis by PXRD revealed the isolated
products to be amorphous.
plate nano-columns of SnSe similar to SnSe nanocrystals
synthesised and reported by K. Jang et al.[22] PXRD analysis of
the two materials (Figure 6) confirm the presence of nano-crystals
with the PXRD patterns for “SnSe” and “SnTe” matching closely
the reported data for the orthorhombic SnSe (Pnma) (JPDS
#481224) and cubic SnTe (Fm3m) (JCPDS #652945)
respectively.[23] The PXRD pattern of the “SnTe” nano-crystals
also shows the presence of a second crystalline component, with
peaks at 2 = 23.06°, 27.60° and 38.30° (Figure 6), which
correspond to the existence of hexagonal-Te (P3221) (JCPDS
#361452) embedded within the nano-crystalline materials
produced.[24]
In contrast, the mono-chalcogen systems 6-8 were more
successful. After workup, the resulting nanoparticles were
analyzed by TEM, the images of the resulting particles are shown
in Figure 4. The particles produced over the 40 min reaction time
varied considerably in size between ca. 0.4 m (Figure5 A), 0.5–
20-50 nm (Figure5 B) and 50–100 nm (Figure5 C).
Conclusions
This work documents the synthesis and characterization of a
series of tin(IV) bis-guanidinate complexes 2-4 and 6-9, and initial
investigations into their utility as precursors for the solvothermal
synthesis of tin(II) chalcogenide nano-crystals. However, while it
should be noted that related complexes have being used in the
deposition of thin films of tin(VI) chalcogenides, by spin coating,[25]
the work reported here, to the best of our knowledge, represents
the first reported use of Sn=E containing systems as single source
precursors for SnS, SnSe and SnTe nanoparticle synthesis, with
control over the oxidation state of the products. The synthesis for
the bis-phenyl chalcogenide complexes 2-4 involves the straight
forward reaction of the easily prepared stannylene 1, with
commercially available diphenyl dichalcogenides Ph2E2 (E = S,
EDX spectra for nanocrystals formed from compounds 6, 7 and 8
respectively all show presence of both Sn and Chalcogen (S Se
or Te) in the approx. 1:1 atom-%, Sn/E ratio for materials
synthesised over both the 40 min reaction time [Sn:S 49:51;
Sn:Se 50:50; Sn:Te 44:56]. It should also be noted that the EDX
spectra also showed the presence of trace amounts of Fe, Cu and
C, the former arising from the TEM grid used to support the
samples (See Supplementary Information).
Se
& Te).The molecular structures of all three complex
[{Me2NC(NCy)2}2Sn[16]2] (E = S (2), Se (3) or Te (4)) have been
determined by single crystal X-ray diffraction experiments,
revealing a family of isoreticular complexes, all of which poses a
distorted pseudo octahedral geometry about the central Sn(IV)
center. As part of our study we wished to access an alternative
synthetic pathway to the mono-chalcogen complexes of the
general form [{Me2NC(NCy)2}2Sn=E] (E = S, Se or Te). To this
end, we investigated the reactivity of the stannylene complex 1
with CBr4, in which the bromoalkane is capable of the oxidative
addition of “Br2” to the Sn(II) centre, resulting in the high yielding
formation
of
the
dibromo
bis-guanidinate
complex
[{Me2NC(NCy)2}2SnBr2] (5), which has been fully structurally
characterised. Subsequent reaction of the dibromo species (5)
with the Li2S, Li2Se or Li2Te respectively results in a new high
yielding synthesis of complexes 6-8.
Figure 6. PXRD patterns for (blue) “α-SnSe” and (orange) “SnTe” nanocrystals
synthesised from precursors 7 and 8 respectively. NB: * marks the presence of
a contaminant within the product.
The potential of complexes 2-4 and 6-8 respectively, as single
source precursors for nano-crystal formation (un-optimised) has
been evaluated. PXRD and EDX analysis provide clear evidence
that under our reaction conditions, the phenyl chalcogenide
precursors 2-4 fail to form the desired SnE materials, due to
incomplete decomposition under our initial reaction conditions. In
contrast precursors 6-8 all appear (by EDX and PXRD analysis)
to produce the desired SnE materials. In the case of precursor 6
PXRD analysis was unable to unequivocally confirm the presence
of crystalline SnS. In this case of precursors 7 and 8, the
production of SnSe and SnTe could be confirmed. In the case of
precursor 8, PXRD analysis suggests the possible presence of
The materials produced from precursor 6 appear from the TEM
images to be thin plate like crystallites. While EDX analysis
showed the presence of Sn & S in a ratio of 49:51 and the electron
diffraction pattern from the powders was inconclusive showing the
presence of only very broad low intensity reflections indicative of
small particle size.
For the nanocrystals formed from precursor 7 the TEM analysis
shows the crystalline material to have aggregated into stacked
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10.1002/ejic.201800071
European Journal of Inorganic Chemistry
FULL PAPER
Synthesis of [{Me2NC(NCy)2}2Sn(TePh)2] (4)
additional hexagonal Te to be present in the nano-crystalline
product. Our future efforts in this area are directed towards the
finding the optimised reaction conditions for the SnE nano-crystal
formation, as well as investigating these materials for other thin
film and nanomaterial production.
Compound 4 was synthesised under identical conditions to compound 2
using 0.8 g of 1 (1.3 mmol) and 0.53 g of diphenyl ditelluride (1.3
mmol).Yield: 0.98 g, 78 %; 1H NMR (C6D6) δ 1.10-2.33 (m, 44 H,
cyclohexyl), 2.58 (s, 12H, N-(CH3)2), 6.87-7.34 (m, 10H, N-CH-C6H5); 13
C
{1H} NMR- (C6D6) δ 26.23 (Cy-CH), 26.49 (Cy-CH), 26.92 (Cy-CH), 27.04
(Cy-CH), 27.30 (Cy-CH), 27.70 (Cy-CH), 33.89 (Cy-CH), 35.05 (Cy-CH),
35.65 (Cy-CH), 35.83 (Cy-CH), 40.17 (N{CH3}2), 56.15 (N-CH), 58.18 (N-
CH), 113.11 (para-CH, TePh), 129.50 (ortho-CH, TePh) 137.57 (Te-C,
TePh), 143.05 (meta-CH, TePh) 165.50 (N-C-N); Elemental analysis found
for C42H66N6Sn1Te2 (expected): C, 49.01 (49.03); H, 6.46 (6.47), N, 8.16
(8.17); Melting point = Dec. 140 °C.
Experimental Section
General Procedures: Elemental analyses were performed using an Exeter
Analytical CE 440 analyser. 1H, 13C 119Sn, 77Se and 125Te NMR spectra
were recorded on
a Bruker Advance 300 or 500 MHz FT–NMR
spectrometers, as appropriate, as saturated solutions at room temperature,
unless stated otherwise; chemical shifts are in ppm with respect to Me4Si
(1H, 13C). TGA and PXRD were performed using a Perkin Elmer TGA7 or
Bruker D8 instrument (Cu-k radiation), respectively.
Synthesis of [{Me2NC(NCy)2}2SnBr2] (5)
Under inert conditions, complex 1 (0.80 g, 1.3 mmol) and CBr4 (0.43 g, 1.3
mmol) were dissolved in THF (20 ml). After stirring for 3 hours the solution
was dried in vacuo to provide a pale yellow solid. The solid was extracted
with 20 ml of toluene, and filtered through Celite™. Concentration and
storage of the filtrate at -28 °C yielded red/brown crystals which were
isolated by filtration and dried in vacuo. Yield: 0.98 g, 98 %; 1H NMR (C6D6)
δ 0.77-2.36 (m, 40 H, cyclohexyl), 2.44(s, 12H, N-(CH3)2), 3.30 (m, 2H, N-
C(H)), 3.45 (m, 2H, N-C(H)); 13C {1H} NMR- (C6D6) δ 25.76 (Cy-CH), 26.30
(Cy-CH), 26.33 (Cy-CH), 26.69 (Cy-CH), 27.13 (Cy-CH), 27.50 (Cy-CH),
33.48 (Cy-CH), 34.26 (Cy-CH), 35.02 (Cy-CH), 35.88 (Cy-CH), 39.83
(N{CH3}2), 56.09 (N-CH), 58.30 (N-CH), 165.49 (s, 2C, N=C=N); 119Sn {1H}
NMR- (C6D6) δ -557; Elemental analysis found for C30H56Br2N6Sn1
(expected): C, 46.24 (46.24); H, 7.24 (7.24), N, 10.79 (10.78); Melting point
= Dec. 151 °C.
All reactions were carried out under an inert atmosphere using standard
Schlenk techniques. Solvents were dried and degassed under an argon
atmosphere over activated alumina columns using an Innovative
Technology solvent purification system (SPS). The Sn(II) bis-guanidinate,
[{Me2NC(NCy)2}2Sn] (1), was prepared by literature method; The reagents
Ph2S2 Ph2Se2 Ph2Te2, and CBr4 were purchased from Aldrich chemicals.
Stoichiometric amounts of the dilithio chalcogenides Li2E (E = S, Se or Te)
were synthesized in-situ via using a slightly modified literature method.[21]
Synthesis of [{Me2NC(NCy)2}2Sn(SPh)2] (2)
Under inert conditions, complex 1 (0.65 g, 1 mmol) and phenyl disulfide
(0.23 g, 1 mmol) were dissolved in THF (20 ml). After stirring for 3 hours
the solution was dried in vacuo to provide a pale yellow solid. The solid
was extracted with hot hexane, and filtered through Celite™.
Concentration and storage of the filtrate at -28 °C yielded pale yellow
crystals, which were isolated by filtration and dried in vacuo. Yield: 0.56 g,
63 %. 1H NMR (C6D6) δ 0.95-2.29 (m, 40 H, Cy-H), 2.39 (s, 12H, N-(CH3)2),
3.19 (m, 2H, N-C(H)), 3.37 (m, 2H, N-C(H)) 6.92-7.13 (m, 6H, ortho and
para-CH, SC6H5), 7.83-7.92 (m, 4H, meta-CH, SC6H5); 13C {1H} NMR-
(C6D6) δ 24.56 (Cy-CH), 24.93 (Cy-CH), 25.15 (Cy-CH), 23.41 (Cy-CH),
25.72 (Cy-CH), 25.98 (Cy-CH), 32.68 (Cy-CH), 33.52 (Cy-CH), 33.67 (Cy-
CH), 34.10 (Cy-CH), 38.81 (N{CH3}2), 54.72 (N-CH), 55.82 (N-CH), 124.00
(para-CH, SPh), 126.5 (ortho-CH, SPh) 135.43 (meta-CH, SPh), 138.36
(S-C, SPh) 164.17 (N-C-N); 119Sn {1H} NMR- (C6D6) δ -578. Elemental
analysis found for C42H66N6S2Sn1 (expected): C, 60.21 (60.21); H, 7.98
(7.94), N, 10.02 (10.03); Melting point = 133 °C.
General synthesis of [{Me2NC(NCy)2}2Sn=Ch] (6 - 8)
Under an inert atmosphere Sulfur (0.06 g, 2 mmol) was suspended in THF
(10 ml) of THF. To this solution 4 ml of a 1 M solution of Li[BEt3H] in THF
was added, forming a solution of Li2S. Complex 5 (1.56 g, 2 mmol) was
dissolved in 5 ml THF and added to the Li2S solution. After stirring
overnight the solvents were removed in vacuo and replaced by 10 ml
toluene. After filtration from precipitated lithium salts the solvent was
removed in vacuo yielding 6 as crystalline residue. Recrystalisation from
toluene yielded 6 as pale yellow crystals in approximately 81% yield.
(1.05g). 1H NMR (300 MHz, C6D6) δ 0.77-2.08 (m, 40 H, Cy-H), 2.69 (s,
12H, NMe2), 3.44 (m, 2H, NCHC5H10), 3.57 (m, 2H, NCHC5H10). 13C{1H}
NMR- (C6D6) 24.87 (Cy-CH) 25.58 (Cy-CH), 25.78 (Cy-CH), 25.85 (Cy-
CH), 25.98 (Cy-CH), 26.61 (Cy-CH), 34.93 (Cy-CH), 35.42 (Cy-CH), 36.12
(Cy-CH), 36.60 (Cy-CH), 39.88 (N{CH3}2), 53.65 (N-CH), 55.74 (N-CH),
165. 39 (N-C-N). 119Sn{1H} NMR (75.8 MHz, C6D6) δSn -248.0.
Synthesis of [{Me2NC(NCy)2}2Sn(SePh)2] (3)
For 7, 0.16 g, 2 mmol of Se was used. Recrystalisation from toluene
yielded 7 as orange crystals in approximately 96% yield. (1.34g). 1H NMR
(300 MHz, C6D6): δH 0.99-2.28 (m, 40 H, Cy-H), 2.34 (s, 12H, NMe2), 3.14
(m, 2H, NCHC5H10), 3.36 (m, 2H, NCHC5H10); 13C{1H} NMR (75.5 MHz,
C6D6): δc 24.41 (Cy-CH), 24.91 (Cy-CH), 25.00, (Cy-CH), 25.45, (Cy-CH),
25.55 (Cy-CH), 25.92 (Cy-CH), 32.24 (Cy-CH), 32.78 (Cy-CH), 34.77 (Cy-
CH), 36.81 (Cy-CH), 38.80 (N(CH3)2), 54.46 (N-CH), 56.22 (N-CH), 167.7
(N-C-N). 119Sn{1H} NMR (75.8 MHz, C6D6): δSn -566.3 77Se{1H} NMR (57.0
MHz, C6D6): δSe -476.01
Compound 3 was synthesised under identical conditions to compound 2
using 0.7 g of 1 (1.1 mmol) and 0.35 g of diphenyl diselenide (1.1
mmol).Yield: 0.92 g, 88 %; 1H NMR (C6D6) δ 1.16-2.45 (m, 40 H,
cyclohexyl), 2.49 (s, 12H, N-(CH3)2), 3.14 3.19 (m, 2H, N-C(H)), 3.44 3.19
(m, 2H, N-C(H)), 6.94-7.12 (m, 6H, ortho and para-CH, SeC6H5), 7.88-8.05
(m, 4H, meta-CH, SeC6H5); 13C {1H} NMR- (C6D6) δ 26.13 (Cy-CH), 26.41
(Cy-CH), 26.55 (Cy-CH), 26.89 (Cy-CH), 27.19 (Cy-CH), 27.51 (Cy-CH),
33.98 (Cy-CH), 34.95 (Cy-CH), 35.24 (Cy-CH), 36.01 (Cy-CH), 40.27
(N{CH3}2), 56.12 (N-CH), 57.49 (N-CH), 126.11 (para-CH, SePh), 128.19
(ortho-CH, SePh) 133.05 (Se-C, SePh), 138.36 (meta-CH, SePh) 165.64
1
(N-C-N); 119Sn {1H} NMR- (C6D6) δ -742 (d, J119Sn-77Se = 1410 Hz); 77Se
For 8, 0.26 g, 2 mmol of Te was used. Recrystalisation from toluene
yielded 8 as red crystals in approximately 82% yield. (1.23g) 1H NMR (300
MHz, C6D6): δH 0.78-2.03 (m, 40 H, Cy), 2.38 (s, 12H, NMe2), 3.52 (m, 4H,
NCHC5H10). 13C {1H} NMR (75.5 MHz, C6D6): δc 26.14 (Cy-CH), 26.95 (Cy-
CH), 30.2 (Cy-CH), 39.9 (N(CH3)2), 56.87 (N-C(H)), 167.33 (N-C-N). 119Sn
{1H} NMR- (C6D6) δ 267.12 (d, 1J77Se-119Sn = 1411 Hz) (d, 1J77Se-117Sn = 1344
Hz; Elemental analysis found for C42H66N6 Se2Sn1 (expected): C, 54.12
(54.15); H, 7.17 (7.14), N, 9.02 (9.02); Melting point = 155 °C.
This article is protected by copyright. All rights reserved.

10.1002/ejic.201800071
European Journal of Inorganic Chemistry
FULL PAPER
{1H} NMR (75.8 MHz, C6D6): δSn -818 ppm (s); 125Te{1H} NMR (157.98 MHz,
C6D6): δTe -1259 ppm.
Bakr, C. A. Muryn, M. A. Malik, P. O'Brien, Inorg. Chem. Front., 2014, 1,
577.
[2]
[3]
O. Madelung, Semiconductors: Data Handbook, Springer, Berlin
London, 2004.
;
General preparation of tin chalcogenide nanoparticles from
precursors 2-4 and 6-9.
a) A. de Kergommeaux, J. Faure-Vincent, A. Pron, R. de Bettignies, B.
Malaman, P. Reiss, J. Am. Chem. Soc., 2012, 134, 11659-11666; b) Y.
Yin, A. P. Alivisatos, Nature, 2005, 437, 664-670.
Under inert conditions, excess dry oleylamine (20 ml) was added to a
hexane (10 ml) solution of the tin chalcogenide precursor (0.5 mmol). The
hexane was removed in vacuo. The reaction mixture was heated at 210 °C
for 40 mins (16 also heated for 20 mins and 2 hours). Once cooled to room
temperature, excess ethanol was added. The precipitate was collected by
centrifugation then purified by ethanol washing and centrifugation a further
three times. The powder was dried in vacuo.
[4]
a) M. Yarema, R. Caputo, M. V. Kovalenko, Nanoscale, 2013, 5, 8398;
b) D. V. Talapin, J.-S. Lee, M. V. Kovalenko, E. V. Shevchenko, Chem.
Rev., 2010, 110, 389-458.
[5]
[6]
P. Marchand, C. J. Carmalt, Coord. Chem. Rev., 2013, 257, 3202-3221.
I. Y. Ahmet, M. S. Hill, A. L. Johnson, L. M. Peter, Chem. Mater., 2015,
27, 7680-7688.
[7]
a) I. Barbul, A. L. Johnson, G. Kociok-Kohn, K. C. Molloy, C. Silvestru, A.
L. Sudlow, Chempluschem, 2013, 78, 866-874; b) T. Wildsmith, M. S.
Hill, A. L. Johnson, A. J. Kingsley, K. C. Molloy, Chem. Commun., 2013,
49, 8773-8775; c) M. S. Hill, A. L. Johnson, J. P. Lowe, K. C. Molloy, J.
D. Parish, T. Wildsmith, A. L. Kingsley, Dalton Trans., 2016, 45, 18252-
18258; d) J. R. Thompson, I. Y. Ahmet, A. L. Johnson, G. Kociok-Kohn,
Eur. J. Inorg. Chem., 2016, 4711-4720.
Crystallography
Experimental details relating to the single-crystal X-ray crystallographic
studies are summarised in the supplementary information (ESI: Table S4).
Crystallographic data were collected at 150 K on a Nonius Kappa-CCD
Diffractometer [(Mok) = 0.71073 Å], and solved by direct methods (SIR-
92)[26] and refined against all F2 using SHELXL–97.[27] All hydrogen atoms
are included in idealised positions and refined using the riding model.
Structure solution was followed by full-matrix least squares refinement and
was performed using the WinGX-1.70 suite of programmes. All non-
hydrogen atoms were refined anisotropically. CCDC 1814545 - 1814548
contains the supplementary crystallographic data for this paper. These
[8]
[9]
T. Tajima, N. Takeda, T. Sasamori, N. Tokitoh, Organometallics, 2006,
25, 3552-3553.
M. Saito, N. Tokitoh, R. Okazaki, J. Am. Chem. Soc., 1997, 119, 11124-
11125.
[10] Y. L. Zhou, D. S. Richeson, J. Am. Chem. Soc., 1996, 118, 10850-10852.
[11] I. Y. Ahmet, M. S. Hill, P. R. Raithby, A. L. Johnson, Submitted for
Publication, 2018.
data
can
be
obtained
free
of
charge
at
[12] T. Chlupaty, Z. Padelkova, F. DeProft, R. Willem, A. Ruzicka,
Organometallics, 2012, 31, 2203-2211.
www.ccdc.cam.ac.uk/conts/retrieving.html [or from the Cambridge
Crystallographic Data Centre, 12, Union Road, Cambridge CB2 1EZ, UK;
fax: +44-1223/336-033; E-mail: deposit@ccdc.cam.ac.uk].
[13] E. Bonnefille, S. Mazières, N. El Hawi, H. Gornitzka, C. Couret, J.
Organomet. Chem., 2006, 691, 5619-5625.
[14] T. Fjeldberg, H. Hope, M. F. Lappert, P. P. Power, A. J. Thorne, J. Chem.
Soc.,Chem. Comm., 1983, 639-641.
Materials Chemistry
[15] a) Y. L. Zhou, D. S. Richeson, Inorg. Chem., 1997, 36, 501-504; b) T.
Chlupaty, Z. Ruzickova, M. Horacek, M. Alonso, F. De Proft, H. Kampova,
J. Brus, A. Ruzicka, Organometallics, 2015, 34, 606-615; c) T. Chlupaty,
Z. Ruzickova, M. Horacek, J. Merna, M. Alonso, F. De Proft, A. Ruzicka,
Organometallics, 2015, 34, 2202-2211.
Thermogravimetric analyses (TGA) were obtained using a Perkin Elmer
TGA 4000 analyser. Data points were collected every second at a ramp
rate of 10 oC min-1 in a flowing (90 mL min-1) N2 stream.
[16] G. Bendt, S. Lapsien, P. Steiniger, D. Bläser, C. Wölper, S. Schulz, Z.
Anorg. Allg. Chem., 2015, 641, 797-802.
TEM Images were captured using a Transmission Electron Microscope
JEOL 1200 EXII. The TEM was used to capture nm scale images of a
range of nano particles and Energy Dispersive X-Ray Spectroscopy (EDS)
was captured within the TEM microscope. Data was processed using INCA
Wave software. All spectra were standardized and calibrated against a
standard copper sample. The magnification, sample level and beam
energy (10 keV) were kept consistent between spectral analyses. Nano-
powders were dispersed from ethanol suspensions onto carbon coated
copper grids and mounted into the TEM. Powder XRD of the nano-
powders were performed on a Bruker D8 Powder Diffractometer, using a
Cu anode X-ray source, (Kα wavelength = 1.5406 Å) at the University of
Bath.
[17] L. Pauling, "The Nature of the Chemical Bond". Third edition, Cornell
University Press, Ithaca, N.Y., 1960.
[18] N. Kano, N. Tokitoh, R. Okazaki, Organometallics. 1997, 16, 2748-2750.
[19] Z. Padělková, P. Švec, V. Pejchal, A. Růžička, Dalton Trans., 2013, 42,
7660.
[20] T. Chlupatý, Z. Růžičková, M. Horáček, J. Merna, M. Alonso, F. De Proft,
A. Růžička, Organometallics, 2015, 34, 2202-2211.
[21] H. Lange, U. Herzog, U. Böhme, G. Rheinwald, J. Organomet. Chem.
2002, 660, 43-49.
[22] K. Jang, I. Y. Lee, J. Xu, J. Choi, J. Jin, J. H. Park, H. J. Kim, G. H. Kim,
S. U. Son, Cryst. Growth Des., 2012, 12, 3388-3391.
[23] H. S. Im, Y. Myung, Y. J. Cho, C. H. Kim, H. S. Kim, S. H. Back, C. S.
Jung, D. M. Jang, Y. R. Lim, J. Park, J. P. Ahn, RSC Adv., 2013, 3,
10349-10354.
Acknowledgements
We thank EPSRC for funding (EP/L0163541 and EP/G03768X/1) and the
Doctoral Training Centre in Sustainable Chemical Technologies (I.Y.A and
J.R.T)
[24] Z. L. Li, S. Q. Zheng, Y. Z. Zhang, R. Y. Teng, T. Huang, C. F. Chen, G.
W. Lu, J. Mater. Chem. A, 2013, 1, 15046-15052.
[25] M. Bouška, L. Střižík, L. Dostál, A. Růžička, A. Lyčka, L. Beneš, M. Vlček,
J. Přikryl, P. Knotek, T. Wágner, R. Jambor, Chem. Eur. J., 2013, 19,
1877-1881.
Keywords: Tin(II) • Guanidinate • sulphur • selenium • tellurium
• Precursors
[26] A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi, M. C. Burla,
G. Polidori, M. Camalli, J. Appl. Cryst., 1994, 27, 435-436..
[27] G. M. Sheldrick, Acta Crystallogr. A, 2008, 64, 112-122.
[1]
a) M. Zhou, G. J. Snyder, L. Li, L.-D. Zhao, Inorg. Chem. Front., 2016, 3,
1449-1463; b) Z. Wang, P. K. Nayak, J. A. Caraveo-Frescas, H. N.
Alshareef, Adv. Mater., 2016, 28, 3831-3892; c) D. J. Lewis, P. Kevin, O.
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10.1002/ejic.201800071
European Journal of Inorganic Chemistry
FULL PAPER
Entry for the Table of Contents
FULL PAPER
SnS, SnSe and SnTe are a potentially
important semiconductor materials.
Here, we have described the
Key Topic* Nanocrystal Precursors,
Tin(II) Chalcogenides
I. Y. Ahmet,[a] [b] Joseph R. Thompson, [a]
[b] and A. L. Johnson *
application of mono chalcogen Sn(IV)
guanidinate precursors, containing
either Sn-Ch or Sn=Ch bonds (Ch =
S, Se and Te) derived from the
oxidative addition of elemental
chalcogenides (S, Se and Te) and
Diphenyl dichalogenides to Sn(II)
guanidinate complexes, for the
production of tin(II) chalcogenide
nano-crystals.
Page No. – Page No.
Oxidative Addition to Sn(II)
Guanidinate Complexes: Nanocrystal
Precursors.
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