Deuterated solvents, chemical shifts

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. 

Solvent Deuterated Form Chemical Shift (Multiplicity) ... 

Table 7.60 Carbon-13 Chemical Shifts of Deuterated Solvents 7.110...

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... 

All NMR spectra were recorded on a Varian A-60 spectrometer at room temperature by Nuclear Magnetic Resonance Specialties, Inc., New Kensington, Pa. Benzene soluble fractions were recorded in deuterated chloroform solution (CDCls) while dimethyl sulfoxide-dc (DMSO-dr.) was the solvent employed for other fractions. (Deuterated chloroform with enrichment of 99.8% was purchased from Bio-Rad Laboratories and dimethyl sulfoxide-dr, with enrichment of 99.6% from Merck, Sharp, and Dohme of Canada.) The internal standard used with the CDCla solutions was tetramethvlsilane and hexamethyl-disiloxane (chemical shift 7 c.p.s.) with DMSO-d . Prior to preparation for NMR recording, the samples were thoroughly dried in a vacuum at 110°C. The NMR tubes were sealed to minimize the absorption of atmospheric moisture. The chemical shifts given in c.p.s. are referred to tetramethylsilane. 

Fifolt [ 130] reported this chemical shift additivity method for fluorobenzenes in two deuterated solvents d6 acetone and d6 dimethyl sulfoxide (DMSO) Close correlations between experimental and calculated fluorine chemical shifts were seen for 50 compounds Data presented in Table 18 result from measurements in deuterochloroform as (he solvent [56] Fluorine chemical shifts calculated by this additivity method can be used to predict approximate values for any substituted benzene with one or more fluorines and any combination of the substituents, to differentiate structural isomers of multisubstituted fluorobenzenes [fluoromtrotoluenes (6, 7, and 8) in example 1, Table 19], and to assign chemical shifts of multiple fluorines in the same compound [2,5 difluoroamline (9) in example 2, Table 19] Calculated chemical shifts can be in error by more than 5 ppm (upfield) in some highly fluonnated systems, especially when one fluonne is ortho to two other fluorines Still, the calculated values can be informative even in these cases [2,3,4,6-tetrafluorobromobenzene (10) in example 3, Table 19]... 

In contrast, a partially deuterated rigid 1,4 diol shows upfield isotope shifts not only in CDC13 but also in acetone- and DMSO-i/fr 122 Again the OH is preferentially solvent-exposed in CDC13, while deuterium prefers to reside in the intramolecular hydrogen bond. Again the OD is preferentially solvent exposed in acetone- and DMSO-d6, while OH prefers to reside in the intramolecular hydrogen bond. The paradoxical commonality of upfield isotope shifts is due to a reversal of the chemical shifts of interior and exterior sites of 1,4 diols in acceptor solvents. The equilibrium constant in DMSO-d6 is... 

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.)... 

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