1,1-Organoboration of tetraynes—routes to new siloles, stannoles and fused heterocycles

Fused Silacarbacycles Containing a Silole Unit: 1,2‐Hydroboration and 1,1‐Organoboration of Alkynyl(vinyl)silanes

“…Furthermore, the molecular structure of 6c could be determined by X-ray diffraction (vide infra). The progress of the reactions is most conveniently monitored by 29 Si NMR spectroscopy, which, together with 13 C NMR spectroscopy, also serves to assign the structure of the final products. In the 29 Si NMR spectra, the signals typical of alkynylsilanes at low frequency [15,19,20] are replaced by 29 Si NMR signals at much higher frequencies, typical of the cyclic structures.…”

“…In the 29 Si NMR spectra, the signals typical of alkynylsilanes at low frequency [15,19,20] are replaced by 29 Si NMR signals at much higher frequencies, typical of the cyclic structures. [20] Particularly helpful for the structural as-signment is the observation of 29 Si satellites in the 29 Si NMR spectra, corresponding to the coupling constants 2 J( 29 Si, 29 Si) (see Figure 1), as well as in the 13 C NMR spectra, corresponding to n J( 29 Si, 13 C) (n = 1,2; see Figures 1 and 2). In 13 C NMR spectra, the broadened signals, owing to partially relaxed 13 C-11 B spin-spin coupling, [21] lend further support to the assignment.…”

“…[20] Particularly helpful for the structural as-signment is the observation of 29 Si satellites in the 29 Si NMR spectra, corresponding to the coupling constants 2 J( 29 Si, 29 Si) (see Figure 1), as well as in the 13 C NMR spectra, corresponding to n J( 29 Si, 13 C) (n = 1,2; see Figures 1 and 2). In 13 C NMR spectra, the broadened signals, owing to partially relaxed 13 C-11 B spin-spin coupling, [21] lend further support to the assignment. The δ 11 B data are in the typical region of triorganoboranes without significant 29 Si satellites in the cases of C-3a, C-6a correspond to coupling with two 29 Si nuclei).…”

“…Similar results were obtained with comparable tetraynes. [13] However, rather harsh conditions are required in order to start the reactions in the case of alkynylsilanes (100°C, several hours), and ring closure appeared to be slow and accompanied by side reactions. Molecular models suggested that steric repulsion between the ethyl and diethylboryl groups prevents a clean intramolecular reaction.…”

A Silole‐Based Efficient Electroluminescent Material with Good Electron‐Transporting Potential

“…[8][9][10] Moreover, siloles own unique electron structure of σ*-π* conjugation between the σ* orbitals of two exocyclic silicon-carbon bonds and π* orbital of the butadiene moiety. [11][12][13] This characteristic endows them with low-lying LUMO energy levels and high electron affinity, making them promising candidates for electron-transporting and light-emitting layers in optoelectronic devices. [14,15] In this work, we designed and synthesized a novel silole derivative with bulky 9,9-dimethylfluorenyl and dimesitylboryl groups at the 2,5-positions of silole ring (Scheme 1), in order to develop efficient light emitters with good electron-transporting ability.…”