Disilene Fluoride Adducts versus β-Halooligosilanides

Abstract

Extending the chemistry of disilene fluoride adducts studied earlier by us, we investigated the formation of 1,1-bis(trimethylsilyl)fluorodiphenylsilylsilanide, which was prepared by reaction of (Me 3 Si) 3 SiSiPh 2 F with KO t Bu. The formed FPh 2 SiSi(Me 3 Si) 2 K displays distinctively different structural and spectroscopic features compared to the earlier reported F(Me 3 Si) 2 SiSi(SiMe 3 ) 2 K. While the latter eliminates metal fluoride upon reaction with MgBr 2 , the respective magnesium silanide is formed from FPh 2 SiSi(Me 3 Si) 2 K. Reaction of (Me 3 Si) 3 SiSiPh 2 Cl with KO t Bu proceeded similarly, but the formed ClPh 2 SiSi(Me 3 Si) 2 K easily undergoes potassium chloride elimination to the disilene Ph 2 SiSi(SiMe 3 ) 2 . Compared to F(Me 3 Si) 2 SiSi(SiMe 3 ) 2 K, which can be regarded as a disilene fluoride adduct, structural, spectroscopic, and reactivity properties of FPh 2 SiSi(Me 3 Si) 2 K distinguish it as a β-fluorodisilanide.

β-Amino- and Alkoxy-Substituted Disilanides

“…These values are close to those found for the structurally related compounds Cp 2 Zr(Cl)Si(SiMe 3 ) 3 (−89.5 ppm) and Cp 2 Hf(Cl)Si(SiMe 3 ) 3 (−79.7 ppm) [32]. The recently reported Cp 2 Zr(Cl)Si(SiMe 3 ) 2 SiPh 2 F exhibited a very similar value of −90.9 ppm [19].…”

“…When comparing the structural parameters of 1a to those of FPh 2 Si(Me 3 Si) 2 SiK·18-crown-6 [19], we found that the contraction of the central Si-Si bond was not so pronounced. This can be due to the fact that the disilene adduct character of 1a is smaller than that of FPh 2 Si(Me 3 Si) 2 SiK·18-crown-6.…”

“…The observed Si-Zr bond length of 2.863(2) Å is close to those found previously for Cp 2 Zr(Cl)Si(SiMe 3 ) 2 SiMe 2 Thex (2.853 Å) and Cp 2 Zr[Si(SiMe 3 ) 3 ] 2 (2.878 Å) [32]. However, compared to the structurally related complex Cp 2 Zr(Cl)Si(SiMe 3 ) 2 SiPh 2 F (d Si-Zr = 2.799(1)/2.803(1) Å) [19], the bond is significantly longer. As expected, complex 3b (Figure 6) was found to be isostructural to 3a , with the Si-Hf bond (2.8339(8) Å) being slightly shorter than the Si-Zr bond of 3a .…”

“…Since compound 1a appeared somewhat different from FPh 2 Si(Me 3 Si) 2 SiK [19], we wondered if it was possible to prepare a silanide containing both the Et 2 NPh 2 Si and the FPh 2 Si groups. For this reason, we reacted 1a with Ph 2 SiF 2 , obtaining neopentasilane 5 in good yield (Scheme 3).…”

“…Recently, we have reported a study on β-halodisilanides XPh 2 SiSi(SiMe 3 ) 2 K (X = F, Cl) [19], which we not obtained by self-condensation of halosilylenoids but by reaction of XPh 2 SiSi(SiMe 3 ) 3 with potassium tert -butoxide. These compounds were found to possess distinctly different properties compared to the self-condensation product F(Me 3 Si) 2 SiSi(SiMe 3 ) 2 K [15,16].…”