Tether-Directed Regioselective Synthesis of an Equatorialface Bisadduct of Azafullerene Using Cyclo-[2]-octylmalonate

Anastasios Stergiou; Karam Asad; Andreas Kourtellaris; Nikos Chronakis; Nikos Tagmatarchis

doi:10.1002/chem.201900273

Tether-Directed Regioselective Synthesis of an Equatorial_face Bisadduct of Azafullerene Using Cyclo-[2]-octylmalonate

Chemistry. 2019 Apr 17;25(22):5751-5756. doi: 10.1002/chem.201900273. Epub 2019 Mar 26.

Authors

Anastasios Stergiou¹, Karam Asad², Andreas Kourtellaris², Nikos Chronakis², Nikos Tagmatarchis¹

Affiliations

¹ Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, 11635, Athens, Greece.
² Department of Chemistry, University of Cyprus, University str. 1, Building No. 13, 2109 Aglantzia, Nicosia, Cyprus.

PMID: 30721558
DOI: 10.1002/chem.201900273

Abstract

Bisazafullerene (C₅₉ N)₂ has been functionalized under aerobic conditions with cyclo-[2]-octylmalonate through a Mannich-type reaction, furnishing the corresponding monoadduct. A regioselective tether-directed Bingel cyclopropanation reaction was then carried out on the azafullerene core to yield a single bisadduct. Spectroscopic analysis of the formed bisadduct showed it to have a C₁ symmetrical structure, making it inherently chiral. Single-crystal X-ray analysis revealed the addition pattern of the azafullerene bisadduct to be equatorial_face . Examination of the optical properties showed the evolution of new absorption bands, which can be used as signatures for the characterization of equatorial_face bisadducts of C₅₉ N. Finally, redox assays showed that the LUMO level of the equatorial_face bisadduct was increased compared to that of the parent (C₅₉ N)₂ .

Keywords: azafullerenes; bisadducts; macrocyclic ligands; regioselectivity; remote functionalization.

Abstract

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