Direct spectroscopic study of unstable molecules with siliconoxygen multiple bonds: low temperature matrix stabilization of (CH3)2SiO and (CD3)2 SiO in the gas phase

An Isolable Silicon Analogue of a Ketone that Contains an Unperturbed Si=O Double Bond

“…Theoretical calculations have predicted a substantial polarization of the Si=O bond (Si δ+ −O δ− ) due to the large difference in electronegativity between Si and O [Si: 1.7; O: 3.5 on the Allred–Rochow scale] and a remarkably weak π(Si−O) bond (58.5 kJ mol −1 ) compared to the σ(Si−O) bond (119.7 kJ mol −1 ) . Indeed, compounds with a Si=O double bond are intrinsically susceptible to auto‐oligomerization, and compounds with an Si=O double bond have so far only been postulated as fleeting intermediates during the formation of the corresponding oligomers (polysiloxanes, silicones), and detected as short‐lived species in low‐temperature matrices …”

Dimethylsilanone Generation from Pyrolysis of Polysiloxanes Filled with Nanosized Silica and Ceria/Silica

“…[27] Prior to this progress in the preparation of stabilized compounds with Si=Ob onds, isolable silanones were unknown under ambient conditions because of their high reactivity.P reviously,they had only been detectedand studied spectroscopically in solid noble gasm atrices at low temperatures. [28][29][30][31] The existence of the silanone molecules and ions had also been observed in the gas phase. [32,33] Several experimental studies have suggested that silanones are formed as intermediates in the thermalr eactions of lowmolecular organosilicon compounds such as silylperoxides and hydrosilylperoxides, siloxetanes, silenes,h ydridosilylketenes, allyloxysilanes, alkoxyvinylsilanes, and polysilylated diazomethanes.…”

“…Prior to this progress in the preparation of stabilized compounds with Si=O bonds, isolable silanones were unknown under ambient conditions because of their high reactivity. Previously, they had only been detected and studied spectroscopically in solid noble gas matrices at low temperatures . The existence of the silanone molecules and ions had also been observed in the gas phase …”

“…These claims of dimethylsilanone formation were usually based on kinetic data and chemical trapping experiments . Among the direct physical methods, matrix isolation IR spectroscopy was used to identify the involvement of this compound as an intermediate in the thermal redistribution of some low‐molecular cyclic and linear siloxanes . Mass spectrometric detection of dimethylsilanone as a product of thermal degradation in polydimethylsiloxane/montmorillonite nanocomposites, however, has only been reported once …”

“…[16][17][18] Amongt he direct physical methods, matrixi solation IR spectroscopy was used to identify the involvement of this compound as an intermediate in the thermal redistributiono fs omel ow-molecular cyclic and linear siloxanes. [28][29][30][31] Mass spectrometric detection of dimethylsilanone as ap roduct of thermal degradation in polydimethylsiloxane/ montmorillonite nanocomposites, however,h as only been reported once. [15] The lack of mass spectrometry (MS) data, and especially TPD MS studies, is surprising given the broad utilization of siloxane/oxidec omposites and the information about reaction kinetics that can be obtainedb yt his technique.…”