Carbo‐Naphthalene: A Polycyclic carbo‐Benzenoid Fragment of α‐Graphyne. (2nd November 2016)

• Record Type: Journal Article
• Authors: Cocq, Kévin; Saffon‐Merceron, Nathalie; Coppel, Yannick; Poidevin, Corentin; Maraval, Valérie; Chauvin, Remi
• Is Part Of: Angewandte Chemie. Volume 128:Number 48(2016)
• Page Start: 15357
• Page End: 15360
• Publication Date: 2016-11-02
• Subjects: Aromatizität -- Carbocyclen -- Dichtefunktionalrechnungen -- Makrocyclen -- Strukturaufklärung; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201608300
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: A ring carbo ‐mer of naphthalene, C32 Ar8 (Ar= p ‐ n ‐pentylphenyl), has been obtained as a stable blue chromophore, after a 19‐step synthetic route involving methods inspired from those used in the synthesis of carbo ‐benzenes, or specifically devised for the present target, like a double Sonogashira‐type coupling reaction. The last step is a SnCl2 /HCl‐mediated reduction of a decaoxy‐ carbo ‐decalin, which is prepared through successive [8+10] macrocyclization steps. Two carbo ‐benzene references are also described, C18 Ar6 and o ‐C18 Ar4 (C≡C‐Si i Pr3 )2 . The carbo ‐naphthalene bicycle is locally aromatic according to structural and magnetic criteria, as revealed by strong diatropic ring current effects on the deshielding of 1 H nuclei of the Ar groups and on the negative value of the DFT‐calculated NICS at the center of the C18 rings (−12.8 ppm). The stability and aromaticity of this smallest fused molecular fragment of α‐graphyne allows prediction of the same properties for the carbon allotrope itself.