RELATIVISTIC EFFECTS IN CHEMICAL SHIFTS 13C NMR OF HALCOHEN-CONTAINING COMPOUNDS

Substituent Effects on 13c Nmr Chemical Shifts in Dialkylaminophenylchlorophosphines

The relative chemical shifts and 2J(PC) coupling constants in the low-temperature limiting spectra of a series of Ph(R,N)PCl compounds [R = Me, Et, PhCH2, ‘Pr and c-Hex] differ for R = primary or secondary. For primary alkyl substituents, the more downfield signal exhibits a large, positive coupling and the more upfield resonance shows a small, negative coupling. These observations are reversed...

The prediction of 1H NMR chemical shifts in organic compounds

www.spectroscopyeurope.com Introduction and historical Proton (H) nuclear magnetic resonance, NMR, spectroscopy began in 1951 with the historic experiment of Arnold, Dharmatti and Packard, when they resolved the three types of hydrogen atoms in ethanol, and this illustrated the immense potential of H NMR in structural organic chemistry. Since this discovery H NMR has become one of the commonest...

Substituent effects on 61Ni NMR chemical shifts.

(61)Ni chemical shifts of Ni(all-trans-cdt)L (cdt = cyclododecatriene, L = none, CO, PMe(3)), Ni(CO)(4), Ni(C(2)H(4))(2)(PMe(3)), Ni(cod)(2) (cod = cyclooctadiene) and Ni(PX(3))(4) (X = Me, F, Cl) are computed at the GIAO (gauge-including atomic orbitals), BPW91, B3LYP and BHandHLYP levels, using BP86-optimised geometries and an indirect referencing scheme. For this set of compounds, substituen...

Computed 13C NMR Chemical Shifts via Empirically Scaled GIAO Shieldings and Molecular Mechanics Geometries. Conformation and Configuration from 13C Shifts

Accurate (rms error ∼3 ppm) predictions of 13C chemical shifts are achieved for many of the common structural types of organic molecules through empirical scaling of shieldings calculated from gauge including atomic orbitals (GIAO) theory with a small basis set and with geometries obtained from computationally inexpensive molecular mechanics methods. Earlier GIAO calculations are shown to be mu...

H Chemical Shifts in NMR