𝔖 Bobbio Scriptorium
✦   LIBER   ✦

CCSD(T) calculation of NMR chemical shifts: consistency of calculated and measured 13C chemical shifts in the 1-cyclopropylcyclopropylidenemethyl cation

✍ Scribed by John F. Stanton; Jürgen Gauss; Hans-Ullrich Siehl

Publisher
Elsevier Science
Year
1996
Tongue
English
Weight
308 KB
Volume
262
Category
Article
ISSN
0009-2614

No coin nor oath required. For personal study only.

✦ Synopsis

The source of conspicuous disagreement between theory and experiment for the chemical shift of C,~ in the 1-cyclopropylcyclopropylidenemethyl cation is identified as an inadequate treatment of electron correlation effects in a previous theoretical study. When the sophisticated CCSD(T) method is used, all calculated 13C chemical shifts agree with the experimental values to within 2.2 ppm. These findings undermine the basis of an earlier suggestion that the selectively poor performance of theory for the C,, nucleus can be attributed to environmental effects in which solvent interactions signficantly perturb the geometrical structure of the cation.

📜 SIMILAR VOLUMES

Calculation of 13C NMR chemical shifts f
Calculation of 13C NMR chemical shifts for aromatic carbons in polyalkylated benzenes
✍ O. Sudmeijer; A. E. Wilson; G. R. Hays 📂 Article 📅 1984 🏛 John Wiley and Sons 🌐 English ⚖ 271 KB

## Abstract ^13^C NMR spectra of a large number of polyalkylated benzenes with branched and linear aliphatic chains have been studied. This resulted in the development of a general procedure that can be used for the calculation of the aromatic chemical shifts in any polyalkylated benzene.

Substituent effects on 1H and 13C NMR ch
Substituent effects on 1H and 13C NMR chemical shifts in α-monosubstituted ethyl acetates: principal component analysis and 1H chemical shift calculations
✍ Ljubica Tasic; Raymond J. Abraham; Roberto Rittner 📂 Article 📅 2002 🏛 John Wiley and Sons 🌐 English ⚖ 126 KB

## Abstract A principal component analysis is applied to α‐monosubstituted ethyl acetates (YCH~2~CO~2~Et), where the observed chemical shifts for the α‐carbon atom, the carbonyl carbon, and the α‐hydrogen atoms are correlated with theoretically derived molecular properties, i.e. the partial charges

Comparison of different theory models an
Comparison of different theory models and basis sets in the calculation of 13C NMR chemical shifts of natural products
✍ Paola Cimino; Luigi Gomez-Paloma; Dario Duca; Raffaele Riccio; Giuseppe Bifulco 📂 Article 📅 2004 🏛 John Wiley and Sons 🌐 English ⚖ 177 KB

The influence of the calculation method in mimicking experimental (13)C NMR chemical shifts of 15 low-polarity natural products singularly containing 10-20 carbon atoms was investigated by employing different quantum chemistry approaches and basis sets, both in the preliminary geometry optimizations

15N and 13C NMR chemical shifts of 6-(fl
15N and 13C NMR chemical shifts of 6-(fluoro, chloro, bromo, and iodo)purine 2′-deoxynucleosides: measurements and calculations
✍ Shi Bai; Olga Dmitrenko; Cecil Dybowski 📂 Article 📅 2009 🏛 John Wiley and Sons 🌐 English ⚖ 244 KB

## Abstract The ^15^N and ^13^C chemical shifts of 6‐(fluoro, chloro, bromo, and iodo)purine 2′‐deoxynucleoside derivatives in deuterated chloroform were measured. The ^15^N chemical shifts were determined by the ^1^H^15^N HMBC method, and complete ^15^N chemical‐shift assignments were made with t