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NMR Isotope Shift Evidence for Conformational Structures of Dimethyl-9,10-Dihydroanthracenes and the 1,4,4-Trimethylcyclohexyl Cation

David A. Forsyth ; Department of Chemistry, Northeastern University, Boston, Massachusetts 02115
Adel M. Moussa ; Department of Chemistry, Northeastern University, Boston, Massachusetts 02115
Chitchanun Panyachotipun ; Department of Chemistry, Northeastern University, Boston, Massachusetts 02115

Puni tekst: engleski, pdf (20 MB) str. 703-711 preuzimanja: 204* citiraj
APA 6th Edition
Forsyth, D.A., Moussa, A.M. i Panyachotipun, C. (1992). NMR Isotope Shift Evidence for Conformational Structures of Dimethyl-9,10-Dihydroanthracenes and the 1,4,4-Trimethylcyclohexyl Cation. Croatica Chemica Acta, 65 (3), 703-711. Preuzeto s https://hrcak.srce.hr/137127
MLA 8th Edition
Forsyth, David A., et al. "NMR Isotope Shift Evidence for Conformational Structures of Dimethyl-9,10-Dihydroanthracenes and the 1,4,4-Trimethylcyclohexyl Cation." Croatica Chemica Acta, vol. 65, br. 3, 1992, str. 703-711. https://hrcak.srce.hr/137127. Citirano 28.02.2021.
Chicago 17th Edition
Forsyth, David A., Adel M. Moussa i Chitchanun Panyachotipun. "NMR Isotope Shift Evidence for Conformational Structures of Dimethyl-9,10-Dihydroanthracenes and the 1,4,4-Trimethylcyclohexyl Cation." Croatica Chemica Acta 65, br. 3 (1992): 703-711. https://hrcak.srce.hr/137127
Harvard
Forsyth, D.A., Moussa, A.M., i Panyachotipun, C. (1992). 'NMR Isotope Shift Evidence for Conformational Structures of Dimethyl-9,10-Dihydroanthracenes and the 1,4,4-Trimethylcyclohexyl Cation', Croatica Chemica Acta, 65(3), str. 703-711. Preuzeto s: https://hrcak.srce.hr/137127 (Datum pristupa: 28.02.2021.)
Vancouver
Forsyth DA, Moussa AM, Panyachotipun C. NMR Isotope Shift Evidence for Conformational Structures of Dimethyl-9,10-Dihydroanthracenes and the 1,4,4-Trimethylcyclohexyl Cation. Croatica Chemica Acta [Internet]. 1992 [pristupljeno 28.02.2021.];65(3):703-711. Dostupno na: https://hrcak.srce.hr/137127
IEEE
D.A. Forsyth, A.M. Moussa i C. Panyachotipun, "NMR Isotope Shift Evidence for Conformational Structures of Dimethyl-9,10-Dihydroanthracenes and the 1,4,4-Trimethylcyclohexyl Cation", Croatica Chemica Acta, vol.65, br. 3, str. 703-711, 1992. [Online]. Dostupno na: https://hrcak.srce.hr/137127. [Citirano: 28.02.2021.]

Sažetak
NMR isotope shifts provide evidence of rapidly equilibrating nonplanar conformations in solution for 9,9-dimethyl-9,10-dihydroanthracene and trans-9,10-dimethyl-9,10-dihydroanthracene. In each case, labeling with a single deuterium in the 9- or 10-position results in two different methyl signals in 13C NMR spectra. The separation between methyl signals is temperature dependent and characteristic of isotopically perturbed equilibria. For cis-9,10- dime thvl-9,10-dihydroanthracene-9-c/[, only intrinsic isotope effects on the chemical shifts are present, indicating a single conformation. Similarly, equilibrium isotope shifts are also seen for the C4 methyls in 1,4,4-trìmethyicyclohexyl cation, thereby ruling out the Co twist-boat as a viable conformation.

Hrčak ID: 137127

URI
https://hrcak.srce.hr/137127

Posjeta: 316 *