Lub hom phiaj ntawm TMS hauv NMR yog dab tsi?
Lub hom phiaj ntawm TMS hauv NMR yog dab tsi?

Video: Lub hom phiaj ntawm TMS hauv NMR yog dab tsi?

Video: Lub hom phiaj ntawm TMS hauv NMR yog dab tsi?
Video: Lis Yaj Pov : Lub Hom Phiaj 2024, Kaum ib hlis
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Siv hauv NMR spectroscopy

Tetramethylsilane yog tus qauv sab hauv uas tau lees paub rau kev ntsuas tshuaj hloov pauv rau 1H, 13C thiab 29Si NMR spectroscopy hauv cov kuab tshuaj organic (qhov twg TMS yog soluble). Vim hais tias tag nrho kaum ob hydrogen atoms nyob rau hauv ib tug tetramethylsilane molecule yog sib npaug, nws 1H NMR spectrum muaj ib tug singlet.

Yog li ntawd, vim li cas TMS thiaj xaiv raws li tus qauv?

TMS yog xaiv rau ntau yam. Qhov tseem ceeb tshaj plaws yog: Hydrogen nuclei hauv TMS muaj kev tiv thaiv zoo heev vim tias silicon muaj cov electronegativity tsawg. Raws li qhov tshwm sim koj yuav tsum tau ua kom cov magnetic teb los ntawm qhov loj tshaj plaws kom coj cov hydrogen rov qab rau hauv resonance.

Tsis tas li, vim li cas CDCl3 siv hauv NMR? CDCl3 yog ib qho hnyav hnyav siv rau NMR tsom xam. Nws yog siv vim hais tias feem ntau cov tebchaw yuav yaj nyob rau hauv nws, nws yog volatile thiab yog li yooj yim mus tshem tawm, thiab nws yog non-reactive thiab yuav tsis pauv nws deuterium nrog protons nyob rau hauv lub molecule tau kawm.

Ntawm no, TMS ncov hauv NMR yog dab tsi?

A ncov ntawm kev hloov tshuaj lom neeg ntawm 2.0 tau hais tias yog downfield ntawm TMS . Ntxiv mus rau sab laug a ncov yog, qhov downfield ntau nws yog. Solvents rau NMR spectroscopy. NMR spectra feem ntau yog ntsuas siv cov kev daws teeb meem ntawm cov khoom raug tshawb xyuas.

Dab tsi ua rau kev tiv thaiv hauv NMR?

Tiv thaiv yog thaum lub nucleus ntsib ib tug qaug zog magnetic teb nyob ib ncig ntawm nws. Qhov no tuaj yeem yog ua rau los ntawm lwm cov atoms "tau mus rau hauv txoj kev" ntawm lub nucleus thiab magnetic teb, los yog lub nucleus nws tus kheej muaj ib tug tsawg spin-flip zog. Deshielding yog thaum lub nucleus muaj kev sib nqus ntau dua nyob ib puag ncig nws.

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