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Philipps-Universität Marburg
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Abstract
In the framework of this dissertation, the three sub-projects presented in the objective
were investigated.
In the first sub-project, the white light generation (WLG) first observed on [(StySn)4S6]
for organotetrel chalcogenide clusters with an adamantane-type structure was investigated
in more detail. For this purpose, the substance library was significantly extended,
in particular in order to analyze necessary prerequisites for the white-light emission. By
systematic variation of both the core composition and the organic substituents the understanding
of the underlying mechanism was improved, and possible ways to selectively
modify the emission spectra were found. In a first study, it could be shown by varying
the tetrel element and the substituents that the amorphicity of the compounds is a basic
requirement for the WLG, since otherwise emission occurs in phase as second harmonic
generation (SHG). By further variation of the organic substituents and replacement of
the sulfur atoms in the inorganic core by selenium atoms, it was further found that - opposing
the initial hypothesis - no pi electron system, but only a cyclic organic substituent
is required, and that the emission seems to be limited by the HOMO-LUMO gap of the
compound. By this it can be ruled out that the WLG is caused by an excitation into real
electronic states. Instead, the observed effect is to be understood as an excitation into
extremely short-lived virtual states that lie within the gap.
In the second part of the project, the reactivity of [(PhSn)4S6] towards transition metal
complexes was investigated, whereby different ternary clusters were obtained. In reactions
with coinage metal complexes with sterically less demanding phosphine ligands, clusters
were synthesized in which the inorganic core of the starting material is retained and one
of the phenyl substituents is replaced with a coinage metal complex fragment. The resulting
clusters have the composition [f(R3P)3MSngfPhSng3S6] (M/R = Cu/Me, Ag/Et,
Au/Me). However, by use of the more bulky phosphine ligand PPh3 the organotin sulfide
cluster is decomposed and subsequently rearranged to a larger ternary cluster with the
composition [(CuPPh3)4(PhSn)18Cu6S31Cl2], which is the first cluster with ternary inorganic
core which was obtained without an additional source of sulfide. Either by oxidation
of this reaction solution or by deliberate use of [Cu(PPh3)2Cl2], the first Cu/Sn/S cluster
with copper atoms in the +II oxidation state was obtained.
Transferring the ligand-exchange reactions carried out with coinage metal complexes to
Group 6 complexes allowed for the preparation of clusters with the composition
[f(PhSn)3SnS6gf(CpM)3S4g] (M = Mo, W) in which an adamantane-type organotinsul-
fide cluster is substituted with a thiotungstate or thiomolybdate cage. The thiometalate
cages correspond to sections of a MoS2 or WS2 layer, which allows the compounds to be
considered as molecular model systems for the adsorption of organotin sulfide clusters on
corresponding surfaces. The binding situation in the molecules was rationalized by DFT
calculations, which revealed a mixed-valence situation and an unusual two-electron-fourcenter
bond connecting the two subunits of the molecules.
In addition to these ternary clusters, whose syntheses always proceeded from [(PhSn)4S6],
the reactivity of the already intensely studied clusters [(R1Sn)3S4Cl] and [(R1Sn)4S6] towards
various zinc compounds was investigated. It was not possible to isolate any ternary
cluster with zinc, but various salts of the defect-heterocubane-type [(RSn)3S4]+ cations
were obtained with chlorostannate and chlorozincate anions. In addition, hydrolysis of
[(R2Sn)4S6] with [ZnCl2(H2O)2] generated in situ resulted in the first mixed oxide/sulfide
cluster with adamantane-type structure, [(R2Sn)4S5O].
In the third sub-project, reactions of the organogermanium trichloride R1GeCl3 with
the bis(trimethylsilyl)chalcogenides gave the dinuclear [(R1GeCl)2E2] (E = S, Se, Te)
complexes, which were already known for the heavy homologue tin. It was shown by NMR
titration experiments that the intermediates in the reaction cascade known for the tin
compounds [((R1GeCl2)2E] and [(R1Ge)3E4Cl] are not formed in the case of germanium.
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Dates
Created: 2019Issued: 2020-10-20Updated: 2020-10-20
Faculty
Fachbereich Chemie
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
Keywords
Organotin compounds Tetrel chalcogenide clusters Nonlinear optics
DFG-subjects
Organozinnverbindungen Tetrelchalkogenidcluster Nichtlineare Optik
DDC-Numbers
540
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Dornsiepen, Eike: Organotetrelchalkogenidcluster mit Heteroadamantanstruktur. : Philipps-Universität Marburg 2020-10-20. DOI: https://doi.org/10.17192/z2019.0247.