The proton NMR signal of TMS is a singlet at 0 ppm ..... right? - WRONG!
Naturally occurring TMS is a mixture of isotopomers. Silicon is 92.2% silicon -28 (I = 0), 4.7% silicon-29 (I = 1/2) and 3.1 silicon-30 (I = 0). Carbon is 98.9% carbon-12 (I = 0) and 1.1% carbon-13 (I = 1/2). Each isotopomer has a different NMR spectrum. The protons are coupled to both 13C and 29Si but not 12C and 28Si.The figure below shows a 400 MHz proton NMR spectrum of TMS. The major isotopomers responsible for the lines are labelled.
tms.jpg
29Silicon NMR is a low sensitivity nucleus which has spin ½ and yields sharp lines (fig. 1). Where there is heteronuclear coupling to proton, the spectrum is usually decoupled.
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是碳跟矽产生了Coupling?
For your interest
The proton NMR signal of TMS is a singlet at 0 ppm ..... right? - WRONG!
Naturally occurring TMS is a mixture of isotopomers. Silicon is 92.2% silicon -28 (I = 0), 4.7% silicon-29 (I = 1/2) and 3.1 silicon-30 (I = 0). Carbon is 98.9% carbon-12 (I = 0) and 1.1% carbon-13 (I = 1/2). Each isotopomer has a different NMR spectrum. The protons are coupled to both 13C and 29Si but not 12C and 28Si.The figure below shows a 400 MHz proton NMR spectrum of TMS. The major isotopomers responsible for the lines are labelled.
tms.jpg
，
肯定不是这个原因。发帖人问的是碳谱，你回答的是氢谱。
但矽谱两旁同样有小峰啊
29Silicon NMR is a low sensitivity nucleus which has spin ½ and yields sharp lines (fig. 1). Where there is heteronuclear coupling to proton, the spectrum is usually decoupled.
但建议楼主找纯TMS再测一次
tms.gif
你看看你的例子的同位素信号和主信号的高度比例，再看看问题图的-1ppm和0ppm的信号高度比例。
你再看看你的例子的同位素信号的耦合常数，再看看问题图假设存在耦合，耦合常数是多少。
好的, 我再看看, 但我也很有兴趣想知道楼主那个小峰是甚麽