Herein a convenient synthetic method to obtain 2,2,3,3-tetrasilyltetrasilane 3 and 2,2,3,3,4,4-hexasilylpentasilane 4 on a multigram scale is presented. Proton-coupled Si NMR spectroscopy and single-crystal X-ray crystallography enabled unequivocal structural assignment. Owing to their unique properties, which are reflected in their nonpyrophoric character on contact with air and their enhanced light absorption above 250 nm, 3 and 4 are valuable precursors for liquid-phase deposition (LPD) and the processing of thin silicon films. Amorphous silicon (a-Si:H) films of excellent quality were deposited starting from 3 and characterized by conductivity measurements, ellipsometry, optical microscopy, and Raman spectroscopy.

Branched higher silicon hydrides Si n H2n+2 with n > 6 were recently found to be excellent precursors for the liquid phase deposition of silicon films. Herein we report the gram-scale synthesis of the novel nona- and decasilanes (H3Si)3Si­(SiH2) n Si­(SiH3)3 (2: n = 1, 5: n = 2) from (H3Si)3SiLi and Cl­(SiPh2) n Cl by a combined salt elimination/dephenylation/hydrogenation approach. Structure elucidation of the target molecules was performed by NMR spectroscopy and X-ray crystallography. 2 and 5 are nonpyrophoric and exhibit a bathochromically shifted UV absorption compared to neopentasilane and the structurally related octasilane (H3Si)3SiSi­(SiH3)3. TG–MS analysis elucidated increased decomposition temperatures and decreased ceramic yields for branched hydrosilanes relative to cyclopentasilane. Otherwise, very similar thermal properties were observed for hydrosilane oligomers with linear and branched structures.

Mixed Si/Ge hydrides SixGeyHz are valuable precursors for the deposition of binary Si-Ge alloys. This work describes the synthesis and full characterization of the previously unknown germaisotetrasilane Ph3GeSi(SiH3)3 (2) on a multigram scale from the reaction of the lithium silanide LiSi(SiH3)3 with Ph3GeCl. The stability of the Si-Ge bond in 2 versus electrophiles and nucleophiles has been investigated with the primary aim of developing new approaches to mixed sila-H-germanes (H3Ge)xSi(SiH3)4-x. With 1 equiv of MeLi, 2 reacted cleanly under cleavage of one Si-Si bond to give Ph3GeSi(SiH3)2Li, which is a valuable synthon for further derivatization. In contrast, the dephenylation reaction of 2 with 1 or 2 equiv of CF3SO3H/iBu2AlH proceeded much less selectively and afforded the desired Ph/H-germasilanes Ph2HGeSi(SiH3)3 and PhH2GeSi(SiH3)3 along with considerable amounts of Si-Ge scission products.

Herein a convenient synthetic method to obtain 2,2,3,3‐tetrasilyltetrasilane 3 and 2,2,3,3,4,4‐hexasilylpentasilane 4 on a multigram scale is presented. Proton‐coupled 29Si NMR spectroscopy and single‐crystal X‐ray crystallography enabled unequivocal structural assignment. Owing to their unique properties, which are reflected in their nonpyrophoric character on contact with air and their enhanced light absorption above 250 nm, 3 and 4 are valuable precursors for liquid‐phase deposition (LPD) and the processing of thin silicon films. Amorphous silicon (a‐Si:H) films of excellent quality were deposited starting from 3 and characterized by conductivity measurements, ellipsometry, optical microscopy, and Raman spectroscopy.