caa a22 4500 465808522 CHVBK 20180323112109.0 cr unu---uuuuu 170327e19900301xx s 000 0 eng 10.1007/BF01160493 doi (NATIONALLICENCE)springer-10.1007/BF01160493 Nonempirical calculations of the effect of molecular fragments on proton chemical shifts in heterocycles [Elektronische Daten] [R. Aminova, A. Aganov, G. Zakirova] We have calculated the relative changes in the proton chemical shifts for a number of six-membered heterocycles (1,3-dioxan, 1,3-oxazine, 1,3-dithiane, trimethylene sulfite, and also their derivatives). A procedure is proposed for estimating the chemical shifts due to the effect of model molecular fragments. In calculating the chemical shifts expected allowance is made for the way in which the given molecule differs in structure from a similar molecule for which the chemical shift is known. The chemical shifts were calculated in the approximation of gradient-invariant atomic orbitals in a Gaussian basis. The calculations reproduce correctly the effect of alkyl substituents and the trends in the chemical shifts as a function of the orientation of the substituents and of the heterocyclic component of the molecule. Plenum Publishing Corporation, 1990 Aminova R. Kazan University, USSR aut Aganov A. Kazan University, USSR aut Zakirova G. Kazan University, USSR aut Theoretical and Experimental Chemistry Kluwer Academic Publishers 26/2(1990-03-01), 136-143 0040-5760 26:2<136 1990 26 11237 https://doi.org/10.1007/BF01160493 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01160493 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Aminova R. Kazan University, USSR aut NATIONALLICENCE 700 1- Aganov A. Kazan University, USSR aut NATIONALLICENCE 700 1- Zakirova G. Kazan University, USSR aut NATIONALLICENCE 773 0- Theoretical and Experimental Chemistry Kluwer Academic Publishers 26/2(1990-03-01), 136-143 0040-5760 26:2<136 1990 26 11237 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer