Highly directional white-light generation was recently reported for the organotin sulfide cluster [(StySn)S] (Sty = p-styryl). This effect was tentatively attributed to the amorphous nature of the material in combination with the specific combination of an inversion-symmetry-free T/E cluster core (T = tetrel, E = chalcogen) with the attachment of ligands that allow π delocalization of the electron density. Systematic variation of T and the organic ligand (R) that runs from T = Si through Ge to Sn and from R = methyl through phenyl and p-styryl to 1-naphthyl provides a more comprehensive view. According to powder X-ray data, only [(PhSi)S] is single-crystalline among the named combinations. Here we demonstrate the fine-tuneability of the nonlinear response, i.e., changing from white-light generation to second-harmonic generation as well as controlling the white-light properties. These are investigated as a function of T, π delocalization of the electron density within R, and the order within the molecular solids.
Adamantane‐type organotin chalcogenide clusters of the general composition [(RT)4S6] (R=aromatic substituent, T=Si, Ge, Sn) have extreme non‐linear optical properties that lead to highly directional white‐light generation (WLG) upon irradiation with an IR laser diode. However, the mechanism is not yet understood. Now, a series of compounds [(RSn)4E6] (R=phenyl, cyclopentadienyl, cyclohexyl, benzyl, CH2CH2(C6H4)CO2Et; E=S, Se), were prepared, characterized, and investigated for their nonlinear optical properties. With the exception of crystalline [(BnSn)4S6], all these compounds exhibit WLG with similar emission spectra; slight blue‐shifts are observed by introduction of cyclopentadienyl substituents, while the introduction of Se in the inorganic core can provoke a red‐shift. These investigations disprove the initial assumption of an aromatic substituent being a necessary precondition; the precondition seems to be the presence of (cyclic) substituents providing enough electron density.
The synthesis of the new bulky vinyllithium reagent (MeIPr=CH)Li, (MeIPr=[(MeCNDipp)2C]; Dipp=2,6‐iPr2C6H3) is reported. This vinyllithium precursor was found to act as a general source of the anionic 2σ, 2π‐electron donor ligand [MeIPr=CH]−. Furthermore, a high‐yielding route to the degradation‐resistant SiII precursor MeIPr⋅SiBr2 is presented. The efficacy of (MeIPr=CH)Li in synthesis was demonstrated by the generation of a complete inorganic divinyltetrelene series (MeIPrCH)2E: (E=Si to Pb). (MeIPrCH)2Si: represents the first two‐coordinate acyclic silylene not bound by heteroatom donors, with dual electrophilic and nucleophilic character at the SiII center noted. Cyclic voltammetry shows this electron‐rich silylene to be a potent reducing agent, rivalling the reducing power of the 19‐electron complex cobaltocene (Cp2Co).
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