ISSN:
1434-193X
Schlagwort(e):
Binaphthyls
;
Chirality
;
Circular dichroism
;
Dendrimers
;
Chemistry
;
General Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
---The absorption and CD spectra of a series of Fréchet (compounds 7-10) and backfolding (compounds 11-12) dendrimers derived from enantiopure (S)-2,2′-dihydroxy-1,1′-binaphthalene have been recorded (THF) in the range 200-350 nm. All the compounds examined show a positive couplet between 200 and 240 nm (1B transition of the 2-naphthol chromophore), the intensity of which (Δεmax of the low-energy branch) ranges between 100 and 40. By means of the DeVoe polarizability model the intensity of the 1B couplet has been calculated vs. the dihedral angle θ. This analysis provides θ angles of 95-110° for the Fréchet dendrimers and 100-110° for the backfolding compounds. These values clearly indicate that the torsional angle θ, defined by the two naphthalene planes, never exceeds the critical value of 110°. This investigation confirms the wide utility of CD spectroscopy to provide geometrical information that cannot be obtained by other types of structural analysis.
Zusätzliches Material:
5 Ill.
Materialart:
Digitale Medien
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