BioNMR
NMR aggregator & online community since 2003
BioNMR    
Learn or help to learn NMR - get free NMR books!
 

Go Back   BioNMR > Educational resources > NMR Questions and Answers
Advanced Search
Home Forums Wiki NMR feeds Downloads Register Today's Posts



Jobs Groups Conferences Literature Pulse sequences Software forums Programs Sample preps Web resources BioNMR issues


Webservers
NMR processing:
MDD
NMR assignment:
Backbone:
Autoassign
MARS
UNIO Match
PINE
Side-chains:
UNIO ATNOS-Ascan
NOEs:
UNIO ATNOS-Candid
UNIO Candid
ASDP
Structure from NMR restraints:
Ab initio:
GeNMR
Cyana
XPLOR-NIH
ASDP
UNIO ATNOS-Candid
UNIO Candid
Fragment-based:
BMRB CS-Rosetta
Rosetta-NMR (Robetta)
Template-based:
GeNMR
I-TASSER
Refinement:
Amber
Structure from chemical shifts:
Fragment-based:
WeNMR CS-Rosetta
BMRB CS-Rosetta
Homology-based:
CS23D
Simshift
Torsion angles from chemical shifts:
Preditor
TALOS
Promega- Proline
Secondary structure from chemical shifts:
CSI (via RCI server)
TALOS
MICS caps, β-turns
d2D
PECAN
Flexibility from chemical shifts:
RCI
Interactions from chemical shifts:
HADDOCK
Chemical shifts re-referencing:
Shiftcor
UNIO Shiftinspector
LACS
CheckShift
RefDB
NMR model quality:
NOEs, other restraints:
PROSESS
PSVS
RPF scores
iCing
Chemical shifts:
PROSESS
CheShift2
Vasco
iCing
RDCs:
DC
Anisofit
Pseudocontact shifts:
Anisofit
Protein geomtery:
Resolution-by-Proxy
PROSESS
What-If
iCing
PSVS
MolProbity
SAVES2 or SAVES4
Vadar
Prosa
ProQ
MetaMQAPII
PSQS
Eval123D
STAN
Ramachandran Plot
Rampage
ERRAT
Verify_3D
Harmony
Quality Control Check
NMR spectrum prediction:
FANDAS
MestReS
V-NMR
Flexibility from structure:
Backbone S2
Methyl S2
B-factor
Molecular dynamics:
Gromacs
Amber
Antechamber
Chemical shifts prediction:
From structure:
Shiftx2
Sparta+
Camshift
CH3shift- Methyl
ArShift- Aromatic
ShiftS
Proshift
PPM
CheShift-2- Cα
From sequence:
Shifty
Camcoil
Poulsen_rc_CS
Disordered proteins:
MAXOCC
Format conversion & validation:
CCPN
From NMR-STAR 3.1
Validate NMR-STAR 3.1
NMR sample preparation:
Protein disorder:
DisMeta
Protein solubility:
camLILA
ccSOL
Camfold
camGroEL
Zyggregator
Isotope labeling:
UPLABEL
Solid-state NMR:
sedNMR


Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
  #1  
Old 05-27-2003, 07:58 AM
Junior Member
 
Join Date: May 2003
Posts: 1
Points: 12, Level: 1
Points: 12, Level: 1 Points: 12, Level: 1 Points: 12, Level: 1
Level up: 23%, 38 Points needed
Level up: 23% Level up: 23% Level up: 23%
Activity: 0%
Activity: 0% Activity: 0% Activity: 0%
NMR Credits: 0
NMR Points: 12
Downloads: 0
Uploads: 0
Default Answered: Does NMR coupling occur between equivalent protons?

for example, in 1,4 dioxane, do the HNMR signals show up as singlets or triplets?
Reply With Quote


Did you find this post helpful? Yes | No
Best Answer - Posted by Cubbi1242
NMR coupling occurs between equivalent protons, but regular NMR spectra are not sensitive to this coupling, because under the conditions of the experiment, spin transitions that would reveal it are forbidden by symmetry, and the signal appears as a singlet.That's also why CH2 and CH3 groups typically appear as singlets, even though geminal H-C-H coupling constant is quite large, 14-18 Hz.All 8 protons in 1,4-dioxane have the same chemical shift, and thus show up as one singlet at 3.692 in CDCl3 or 3.757 in D2O.
Answer provided by Yahoo Answers.

  #2  
Old 05-27-2003, 07:58 AM
Junior Member
 
Join Date: May 2003
Posts: 1
Points: 2, Level: 1
Points: 2, Level: 1 Points: 2, Level: 1 Points: 2, Level: 1
Level up: 3%, 48 Points needed
Level up: 3% Level up: 3% Level up: 3%
Activity: 0%
Activity: 0% Activity: 0% Activity: 0%
NMR Credits: 0
NMR Points: 2
Downloads: 0
Uploads: 0
Default Does NMR coupling occur between equivalent protons?

1,4-Dioxane has a single peak at 3.70 ppm.
Reply With Quote


Did you find this post helpful? Yes | No
  #3  
Old 05-28-2003, 11:40 PM
Junior Member
 
Join Date: May 2003
Posts: 1
Points: 2, Level: 1
Points: 2, Level: 1 Points: 2, Level: 1 Points: 2, Level: 1
Level up: 3%, 48 Points needed
Level up: 3% Level up: 3% Level up: 3%
Activity: 0%
Activity: 0% Activity: 0% Activity: 0%
NMR Credits: 0
NMR Points: 2
Downloads: 0
Uploads: 0
Provided Answers: 1
Default Does NMR coupling occur between equivalent protons?

NMR coupling occurs between equivalent protons, but regular NMR spectra are not sensitive to this coupling, because under the conditions of the experiment, spin transitions that would reveal it are forbidden by symmetry, and the signal appears as a singlet.That's also why CH2 and CH3 groups typically appear as singlets, even though geminal H-C-H coupling constant is quite large, 14-18 Hz.All 8 protons in 1,4-dioxane have the same chemical shift, and thus show up as one singlet at 3.692 in CDCl3 or 3.757 in D2O.
Answer provided by Yahoo Answers.
Reply With Quote


1 out of 1 members found this post helpful. Did you find this post helpful? Yes | No
Reply
Similar Threads
Thread Thread Starter Forum Replies Last Post
[KPWU blog] add protons (hydrogens) to structure
add protons (hydrogens) to structure A list of online servers or programs as I know which can add hydrogens on the structures (most likely determined by X-ray crystallography). WHATIF server (http://swift.cmbi.ru.nl/servers/html/index.html) –> check “Hydrogen (bonds)” in the left frame Molprobity server (http://molprobity.biochem.duke.edu/) –> after uploading a PDB file, you will see “add hydrogen” in the online interface. HAAD: (a computer http://stats.wordpress.com/b.gif?host=kpwu.wordpress.com&blog=76132&post=662&subd=kpwu&ref=&feed=1 Go to KPWU blog to read complete post.
nmrlearner News from NMR blogs 0 02-25-2012 12:16 AM
[NMR tweet] PCCP: Singlet nuclear magnetic resonance of nearly-equivalent spins (Levitt): http://bit.ly/ijagDs
PCCP: Singlet nuclear magnetic resonance of nearly-equivalent spins (Levitt): http://bit.ly/ijagDs Published by solidstateNMR (New SSNMR Papers) on 2011-02-11T18:10:53Z Source: Twitter
nmrlearner Twitter NMR 0 02-11-2011 06:14 PM
[Stan NMR blog] Noise Figure and Equivalent Input Noise
Noise Figure and Equivalent Input Noise An educational article about the definitions of - and the relation between - the two concepts. More...
nmrlearner News from NMR blogs 0 08-21-2010 06:14 PM
Chemical shift of protons?
Can someone give me the answers to the chemical shift of the protons in this compound: CH3CH2OCH2CH(CH3)COOH? Of if you can explain how to get the chemical shift it would be quite helpful as the info online does not really help me.
Tim Mrudande NMR Questions and Answers 1 01-16-2005 08:23 AM
NMR of Naphthalene: why are the alpha-protons more downfield than the beta- protons?
Hi, can you please help me explain why the alpha-protons of naphthalene are further downfield? I know that the protons at the alpha position must be more deshielded, but I don't know how to explain why they have less electron density compared to the beta protons. Does this have to do with the number of double bonds that can be drawn in different resonance structures? Thanks for your help!Thanks so much!
flan318 NMR Questions and Answers 1 12-24-2002 12:07 PM



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



BioNMR advertisements to pay for website hosting and domain registration. Nobody does it for us.



Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright, BioNMR.com, 2003-2013
Search Engine Friendly URLs by vBSEO 3.6.0

All times are GMT. The time now is 08:42 PM.


Map