Mercury-sensitized photolysis of Me
2
SiH
2
yields in the primary step an Me
2
HSi radical and an H atom
with a quantum yield of one. The Me
2
HSi radicals undergo a
combination reaction [k(2)] as well as two kinds of
disproportionation reactions leading to dimethylsilylene
[k(3)] and 1-methylsilaethene [k(4)]. The following
branching ratios have been determined:
k(3)/[k(2)+k(3)+k(4)]=0.64
±0.10 and
k(4)/[k(2)+k(3)+k(4)]0.007.
For Me
3
Si radicals the branching ratio for
disproportionation was also determined and a value of 0.063 was
obtained.
Me 2 SiH 2 的
汞敏化光解第一步产生一个 Me 2 HSi 自由基和一个 H 原子,量子产率为 1。Me 2 HSi 自由基会发生一个结合反应[k(2)]以及两种歧化反应,最终生成二甲基
硅烷基[k(3)]和 1-甲基
硅烷基[k(4)]。测定的支化率如下:k(3)/[k(2)+k(3)+k(4)]=0.64 ±0.10,k(4)/[k(2)+k(3)+k(4)]0.007。对于 Me 3 Si 自由基,还测定了歧化支化率,结果为 0.063。