Proton Magnetic Resonance Spectra of Thiazoles. Chemical Shifts and Substituent Effects.

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...

Proton magnetic resonance spectra of amino acids.

High resolution nuclear magnetic resonance spectroscopy has already proved its ability to yield valuable information on the structure, reactivity and exchange rate of a variety of compounds. Although its application to substances in aqueous solution has often been limited by solubility and exchange, it has been possible to detect the spectra of several amino acids and dipeptides in water (I). T...

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...

Chemical shift nonequivalence in proton magnetic resonance spectra of glycyl peptides.

Density functional calculation of nuclear magnetic resonance chemical shifts

A current-density functional theory for the calculation of nuclear magnetic resonance chemical shifts is presented. If the Kohn–Sham orbitals are expanded in a finite basis set, one of the main problems is the strong dependency of the results with respect to a shift of the gauge origin of the vector potential which describes the external magnetic field. Two computational schemes implementing bo...