How to determine E vz Z olefin isomer when proton resonances orverlap?

3 1 16651
answers votes views
We have an olefin, R1-CH=CH-R2 where proton resonances overlap. Is there a way to determine olefin isomer - E (trans) vs...
Posted: Evgeny Fadeev 5771 / Updated: Cleber Barreto 73 Jul 10 '10 at 08:07

How to best correlate Deuterium with other nuclei by NMR?

2 0 5k
answers votes views
Hello, I've been asked to solve a problem of assigning a positon of deuteration on a molecule, where structure of the de...
Posted: Evgeny Fadeev 5771 / Updated: kiscs kiscs 21 May 17 '10 at 16:43

How to determine physical orientation of X and Y shims?

2 0 4k
answers votes views
Hello, I need to help solids lab at our UCI site - they have a custom probe and need to orient it properly in order to e...
Posted: Evgeny Fadeev 5771 / Updated: Jerry Hirschinger 199 Sep 13 '10 at 08:46

Limit Testing by NMR?

3 1 9k
answers votes views
Is it possible to use NMR for limit testing of trace impurities in pharmaceutical drug substances? What are the conside...
Posted: Chris Kirchner 11 / Updated: sekhar Talluri 621 May 23 '10 at 11:49

How to assign (perturbed) resonances when structure is known?

1 0 5k
answers votes views
I had two problems like this one recently: have protein (in solution) of known general structure resonance assignments...
Posted: Evgeny Fadeev 5771 / Updated: Aleksandr Yakimov 11 Apr 25 '10 at 01:17

How to confirm structure of propane by NMR?

2 2 5k
answers votes views
I will really need your help. I am chemist working in the oil buisness and I am interesting is it possible to analyze pr...
Posted: Silvija 21 / Updated: ron daedalus 11 Apr 21 '10 at 09:18

How to explain binary-like pattern in the nutation curve in a simple 90 degree pulse calibration experiment?

1 0 7k
answers votes views
Hello, I wanted to ask this in a while. Finally a sample arrived that shows this behavior and I made a screenshot (below...
Posted: Evgeny Fadeev 5771 / Updated: Joseph DiVerdi 146 Apr 15 '10 at 17:23

Why are my acetic acid-d4 solvent peaks off from the expected ppm value?

1 1 8k
answers votes views
Hello there. After running an 1H-NMR experiment I observed the acetic acid-d4 solvent peaks at 11.54 and 21.16 ppm (off...
Posted: BONA 11 / Updated: Evgeny Fadeev 5771 Apr 12 '10 at 15:08

How to determine the conformation of cis-cyclohexyl derivative by NMR?

1 1 4k
answers votes views
This cis-cyclohexyl derivative with two big substitutes (A and B) may has two conformational isomers, 1 and 2. How to ...
Posted: Jack 31 / Updated: Evgeny Fadeev 5771 Apr 05 '10 at 12:36

What is the definition of term Saturation and what are ways to achieve that state?

2 1 20567
answers votes views
Hello. What is the best definition to the state of "saturation" in the context of NMR? No phase coherence in the transv...
Posted: Evgeny Fadeev 5771 / Updated: Joseph DiVerdi 146 Apr 06 '10 at 20:44
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