Deuterated solvents proton chemical shifts

Identification of unknown compounds NMR spectroscopy provides the forensic analyst with one of the most powerful techniques for identification of unknown compounds. The full range of structural elucidation techniques of modern spectrometers is available. First, the analyst obtains a high-resolution proton (NMR) spectrum in an appropriate deuterated solvent. The chemical shifts and integration in the spectrum give an indication of the types (aliphatic, olefinic, aromatic, etc.) and relative numbers of protons present in the molecule. The appearance of the coupling patterns in the molecule often provides very useful structural information. If the identity of the unknown cannot be determined from the results of the NMR study alone, the analyst next obtains information. The NMR spectrum gives a count of the number of nonequivalent carbon atoms, as well as the types of carbon (aliphatic, aromatic, carbonyl, etc.) present in the unknown. The number of protons attached to each carbon may... 

Instrumentation. H and NMR spectra were recorded on a Bruker AV 400 spectrometer (400.2 MHz for proton and 100.6 MHz for carbon) at 310 K. Chemical shifts (< are expressed in ppm coupling constants (J) in Hz. Deuterated DMSO and/or water were used as solvent chemical shift values are reported relative to residual signals (DMSO 5 = 2.50 for H and 5 = 39.5 for C). ESl-MS data were obtained on a VG Trio-2000 Fisons Instruments Mass Spectrometer with VG MassLynx software. Vers. 2.00 in CH3CN/H2O at 60°C. Isothermal titration calorimetry (ITC) experiments were conducted on a VP isothermal titration calorimeter from Microcal at 30°C. 

Note that 5h is the chemical shift for protons in the residual protonated solvent (6c is that for the deuterated solvent). The intensities of the peaks in the multiplets will not be the same as for the same multiplets in H spectra as the coupling is to D (= "H), a spin I nucleus... 

Table A3.10 Chemical shifts of residual protons in deuterated solvents 1431...

Table A3.6 Chemical shift of protons attached to atoms other than carbon (all signals are sensitive to solvent, concentration and temperature and are removed by deuteration)...

CHEMICAL SHIFTS AND MULTIPLICITIES OF RESIDUAL PROTONS IN COMMERCIALLY AVAILABLE DEUTERATED APPENDIX G SOLVENTS (MERCK CO., INC.)... 

The best clue to why this is so involves the chemical shifts of the OH, NH, and SH protons in these molecules. They are all the same within experimental error 4.90 p.p.m. for glycine, 4.80 p.p.m. for the aminothiol, and 4.84 p.p.m. for EDTA. They all correspond to the same species HOD. Exchange between XH (where X = O, N, or S) protons is extremely fast, and the solvent, D2O, supplies a vast excess of exchangeable deuteriums. These immediately replace all the OH, NH, and SH protons in the molecules with D, forming HOD in the process. Recall that we do not see signals for deuterium atoms (that s why deuterated solvents are used). They have their own spectra at a different frequency. 

Chemical Shifts, Multiplicities, and Coupling Constants of Residual Protons in Commercially Available Deuterated Solvents... 

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