The Gas‐Phase Oxidation of Silyl Radicals by Molecular Oxygen: Kinetics and Mechanisms

Abstract

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Cleavage of Carbene-Stabilized Disilicon

“…We now report the unexpected silicon–silicon double bond cleavage and borane insertion reactions of 1 when combined with BH 3 ·THF and describe the formation, molecular structures, and computational investigations of 2 and 3 , the novel ensuing products. The “push–pull” stabilization of the parent silylene ( : SiH 2 ) unit in 2 is significant since SiH 2 has been observed as an important intermediate in the chemical vapor deposition (CVD) of silicon film by pyrolysis of silane (SiH 4 ) …”

Counterintuitive Chemistry: Carbene Stabilization of Zero-Oxidation State Main Group Species

“…For example, the 1:4 reaction of 28 with BH 3 ·THF in toluene resulted in the cleavage of the SiSi double bond, giving 34 in 72% yield (Scheme ). The highly reactive SiH 2 species has been observed as an intermediate in the chemical vapor deposition of silicon film via SiH 4 pyrolysis …”

N-Heterocyclic Carbene—Main-Group Chemistry: A Rapidly Evolving Field

“…Notably, the corresponding BH 3 ·THF reaction of the mixture consisting of 4 and the free NHC ligand L: ( 4 to L: = 5:1) leads to both 11 (30% yield) and 12 (28% yield) (Scheme ), which can be readily separated because of their different solubilities in toluene. SiH 2 is highly reactive and has been observed as an intermediate in the chemical vapor deposition of the silicon film via SiH 4 pyrolysis . Compound 11 represents the first “push–pull”-stabilized parent silylene (SiH 2 ) that accepts electron donation from the carbene while donating an electron pair to the L:Si(H)(B 3 H 7 )BH 2 fragment …”

“…SiH 2 is highly reactive and has been observed as an intermediate in the chemical vapor deposition of the silicon film via SiH 4 pyrolysis. 95 Compound 11 represents the first "push− pull"-stabilized parent silylene (SiH 2 ) that accepts electron donation from the carbene while donating an electron pair to the L:Si(H)(B 3 H 7 )BH 2 fragment. 96 Rivard 97 Notably, the "push−pull"-stabilized heavier analogues of SiH 2 (i.e., GeH 2 and SnH 2 ) have also been achieved by Rivard et al 98−101 The X-ray structure of 11 (Figure 10) shows that the top reaction in Scheme 5, involving one equiv of 4 and four equiv of BH 3 •THF, results in cleavage of the SiSi double bond in 4 with insertion of a BH 2 unit between two silicon(II) atoms.…”