Synthesis and reactivity of silylated tetrathiafulvalenes

Disilane-bridged architectures: an emerging class of molecular materials

Disilanes are organosilicon compounds that contain saturated Si-Si bonds. The structural characteristics of Si-Si single bonds resemble those of C-C single bonds, but their electronic structure is more similar to that of C[double bond, length as m-dash]C double bonds, as Si-Si bonds have a higher HOMO energy level. These organosilicon compounds feature unique intramolecular σ electron delocalization, low ionization potentials, polarizable electronic structure, and σ-π interaction. It has been demonstrated that the employment of disilane units (Si-Si) is a versatile and effective approach for finely adjusting the photophysical properties of organic materials in both solution and solid states. In this review, we present and discuss the structure, properties, and relationships of novel σ-π-conjugated hybrid architectures with saturated Si-Si σ bonds. The application of disilane-bridged σ-conjugated compounds as optoelectronic materials, multifunctional solid-state emitters, CPL, and non-linear optical and stimuli-responsive materials is also reviewed.

London dispersion-driven hetero-aryl-aryl interactions in 1,2-diaryldisilanes

Non-covalent aryl-aryl interactions for the molecular structures of three 1,2-diaryltetramethyldisilanes X5C6-(SiMe2)2-C6Y5 (X ≠ Y; X, Y = H, F, Cl) were studied by single crystal X-ray and gas electron diffraction as well as by SAPT calculations. Aryl-aryl interactions cause all to adopt exclusively rather untypical eclipsed syn-conformers in the gas phase, and C6F5-(SiMe2)2-C6Cl5 also in the solid state.

6,6-Dimethyl-2H,5H,6H,7H-1,3-dithiolo[4,5-f][1,5,3]dithia-silepin-2-one

In the structure of the title compound, C₇H₁₀OS₄Si, the carbonyl O atom lies in the plane of the five-membered dithiole ring with a deviation of only 0.022 (2) Å. The seven-membered ring adopts a chair conformation. The crystal packing is stabilized by S⋯O [3.096 (4) Å] and S⋯S [3.620 (4) Å] contacts, together with C—H⋯S inter­actions.

The competition between Si-Si and Si-C cleavage in functionalised oligosilanes: their reactivity with elemental lithium

The reaction of aryl-substituted disilanes with elemental lithium is a common method for the preparation of lithiosilanes and the subsequent synthesis of functionalised oligosilanes, especially of enantiomerically pure compounds. A series of alkyl- and arylsubstituted di- and trisilanes has been investigated with respect to their reactivity against elemental lithium. Thereby, depending on the substituents, silicon-silicon bond cleavage of the central Si-Si unit and/or silicon-carbon bond cleavage to arenes are observed. Quantum chemical studies provide a deeper insight into the ongoing processes. The reactive centre can be estimated by both, bond elongation after electron transfer and frontier orbital interactions (pi-bonding and sigma-antibonding part). Aromatic substituents at the silicon atoms proved to be necessary for the processing of any cleavage reaction in the studied systems by stabilising the radical anion after electron transfer at the corresponding di- or trisilane. Yet, selective cleavage reactions do not depend on the number of arenes.