Sat, Apr. 29th, 2006, 11:03 pm
CDCl3 is a common solvent used for NMR analysis. It is used because most compounds will dissolve in it, it is volatile and therefore easy to get rid of, and it is non-reactive and will not exchange its deuterium with protons in the molecule being studied. It is also "silent" in the NMR and will not show peaks to interfere with the analysis of the compound of interest. However, whenever CDCl3 is used as an NMR solvent, a small singlet is always observed at 7.26 delta. What is this peak due to and why the heck is it there?
Sun, Apr. 30th, 2006 06:33 am (UTC)
Incomplete deuteration of the solvent, there is a trace of CHCl3 in the solvent. Absolutely pure CDCl3 is extremely difficult (and expensive) to make (if not out and out impossible with current technology).
Sun, Apr. 30th, 2006 01:13 pm (UTC)
All NMR solvents have a signal. If you have 99.9% D substitution you still have alot of H relative to your compound. Alot of books have a table of common NMR solvents and where they appear on the spectra.
Mon, May. 1st, 2006 12:06 pm (UTC)
you will probably find that your NMR takes a reference from the solvent peak this eliminates the need to put TMS in your samples
Wed, Oct. 11th, 2006 04:41 pm (UTC)
(Anonymous): The solvent of CDCl3
That peak is corresponded to the relative small conc of CHCl3, b/c CHCl3 is one of the reagents that is used to make CDCl3. It is like a little fraction due to the H+ activity in the CHCl3. Try to do the NMR analysis with CDCl3 (by ifself), with H2O, & methanol, & acetone, & with CHCl3 to check the reference, you will see the common peak but variation in sizes.
Sun, Oct. 5th, 2008 06:06 pm (UTC)
why intensities (the triplet)of CDCl3 peaks are the same in 13C spectra. whereas for DMSO-d6 the 7 lines are of different intensities.
Sat, Jun. 13th, 2009 05:58 pm (UTC)
D has I=1, according to pascal's triangle, this will lead to the different peak intensity 1:3:6:7:6:3:1 in DMSO.
Thu, Apr. 7th, 2011 01:59 pm (UTC)
(Anonymous): Residual peak in CDCl3
I am observing two singlets in CDCl3 i.e at 1.56 and 1.53 ppm! Is it possible to have HOD peak?