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8.1 通过一个键的C与H偶合除了化学位移之外,C—H的偶合常数也能提供重要的信息,测量J值时必须取不去偶或用交替脉冲双共振方法。这两种方法都需时较长,并且要求样品量较多。~1J_(CH)也可从~1H谱的~(13)C卫星线测得。 ~1J_(CH)在120-130Hz之间~2J(CH)、~3J(CH)~4J(CH)都小于
8.1 Coupling of C to H via a bond In addition to the chemical shift, the coupling constant of C-H can also provide important information. The J-value must be either non-decoupled or alternatively pulsed bi-resonant. Both of these methods take longer and require more sample volume. ~ 1J_ (CH) can also be measured from ~ 1H spectra of ~ (13) C satellite. ~ 1J_ (CH) between 120-130Hz ~ 2J (CH), ~ 3J (CH) ~ 4J (CH) are less than