2007
DOI: 10.1002/mrc.2043
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The prediction of 1H chemical shifts in amines: a semiempirical and ab initio investigation

Abstract: Twenty one conformationally fixed amines and their N,N-dimethyl derivatives were obtained commercially or synthesized. These included cis and trans 4-t-butyl cyclohexylamine, 2-exo and 2-endo norbornylamine, 2-adamantylamine, 4-phenylpiperidine, 1-napthylamine and tetrahydro-1-napthylamine. The (1)H NMR spectra of these amines were measured in CDCl(3) solution, assigned and the (1)H chemical shifts given. This data was used to investigate the effect of the amino group on the (1)H chemical shifts in these molec… Show more

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Cited by 10 publications
(4 citation statements)
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“…1 H is one of the important nuclei in chemistry because it has high sensitivity and vast occurrence in organic compounds. Despite this common occurrence, there are few studies on the 1 H NMR chemical shifts of the amino group (33,34). Recently, Alkorta and Elguero (35) calculated 1 H shieldings in amines at the B3LYP/6-311þþG** level of theory, which has been suggested to ''choose the highest reasonable possible level of theory'' for calculations of molecular magnetic properties (36).…”
Section: H Chemical Shiftsmentioning
confidence: 99%
“…1 H is one of the important nuclei in chemistry because it has high sensitivity and vast occurrence in organic compounds. Despite this common occurrence, there are few studies on the 1 H NMR chemical shifts of the amino group (33,34). Recently, Alkorta and Elguero (35) calculated 1 H shieldings in amines at the B3LYP/6-311þþG** level of theory, which has been suggested to ''choose the highest reasonable possible level of theory'' for calculations of molecular magnetic properties (36).…”
Section: H Chemical Shiftsmentioning
confidence: 99%
“…We have used previously the standard GIAO approach to calculate the 1 H shifts of a variety of organic molecules (amines 25 , amides 11 and phenols 10 ) using the same density function theory and the previous basis set for the geometry optimization and GIAO calculations. This approach gives in general good agreement with the observed shifts, but always, there are a number of exceptions.…”
Section: Introductionmentioning
confidence: 99%
“…Secondly, we have used the GIAO function in the programme gaussian03 at the B3LYP/6‐31++g [2d,p] level . This level was used in our previous calculations, and the use of the same level allows all the calculations to be considered together if required. The MMFF94 geometries from PCMODEL were used here also.…”
Section: Introductionmentioning
confidence: 99%
“…Figure 2 shows the comparison of the experimental chemical shifts with those computed after scaling 9 at the SCRF-B3LYP/6-31+G**//B3LYP/6-31G* level using Gaussian. 10 The best agreement between calculated and experimental chemical shift is obtained for the diastereomer SR-RS; the larger discrepancies for the SS model at 6.46 and 5.79 ppm refer to the N-H proton (a known difficult case for standard ab initio calculations 11 ), and to the aforementioned aromatic proton, whose chemical shift is instead well reproduced by the computations on the SR-RS model. The better agreement of computed spectra for the SR configuration is grossly unchanged by consideration of the lowest energy conformer out of the 18 used to compute the spectra (See SI).…”
Section: Figure 1 Cosy-nmr Ofmentioning
confidence: 95%