1-H NMR Spectroscopy Lab - Josh Carlberg P.O 413 1-H NMR...

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Josh CarlbergP.O 4131-H NMR Spectroscopy Lab.Post LabOverview of lab and objectives:In the proton NMR spectroscopy lab we studied how NMR spectroscopy theory appliesto H NMR spectras. The lab explained how the NMR spectra peaks that we are seeing arecoming from the nuclei jumping from a lower to higher energy state. It should also be noted thatWhat NMR spectroscopy is measuring the amount of light absorbed at a specific ppm value.The ppm value is the amount of energy we see released when the nuclei relaxes down from thehigh energy state to the low energy state. This being said the NMR spectras only show uniquenuclei or protons which means if there are two molecules that are the same they will share thesame ppm value and will be seen as one peak. Like in 13-C NMR the replacement method andsymmetry method are applied in similar ways. We likewise see the hydrogens are affected in thesame way as in carbons were in 13-C NMR spectras; As a nuclei approaches groups that areelectron withdrawing groups/atoms(O,Cl,N,Br) it will become more deshielded resulting in apeak/signal that is further downfield(higher ppm value).Up unto this point 13-C NMR spectrasand H NMR spectras share similarities. What makes H NMR spectras more complex than 13-CNMR spectroscopy is that there are signals instead of peaks. T splitting, incidental overlap dueto the much smaller scale(0-12 ppm vs 0-220 ppm)a of 1-H NMR, and diastereotopic protons.H NMR signals allow us to know the hybridization state of the carbon the proton is bonded to aswell as the types of atoms or groups near the H that give rise to the signal. This is explainedmore thoroughly through the multiplicity rule. The multiplicity rule states that n neighboringprotons split the signal of a proton into n + 1 peaks.Since a hydrogen bonded to a carboncould bond to three other carbons with we could see as many as 10 peaks (9 neighbors)in asignal.The integral value (area under the signal) allows us to know how many equivalenthydrogen atoms are at the signal. By taking the integral value The number of peaks in a peak

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Term
Fall
Professor
NoProfessor
Tags
Atom, Nuclear magnetic resonance, Proton NMR, NMR Spectroscopy Lab

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