title: Synthesis and switching the aromatic character of oxatriphyrins(2.1.1).
abstract: Triangularly shaped, contracted porphyrinoids belong to a group of molecules where the geometry significantly modifies the observed electronic properties. The need for a controllable, effective, and widely applicable approach to triphyrins drives extensive research towards macrocyclic materials that act as potential controlling motifs by switching their aromaticity. Two isomeric thiophene-fused triphyrins(2.1.1) were synthesized by applying an innovative approach. Spectroscopic techniques (NMR, UV/Vis) show that both macrocycles are aromatic and quantitatively convert into anti-aromatic structures after reduction with a zinc amalgam. The reduced forms were stabilized through boron(III) coordination, thereby allowing the observation of anti-aromatic 16 π delocalization within a contracted porphyrin.
authors.affiliation: Department of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50383 Wrocław (Poland) http://llg.chem.uni.wroc.pl/. milosz.pawlicki@chem.uni.wroc.pl.
authors.forename: Miłosz
authors.initials: M
authors.lastname: Pawlicki
authors.forename: Karolina
authors.initials: K
authors.lastname: Hurej
authors.forename: Ludmiła
authors.initials: L
authors.lastname: Szterenberg
authors.forename: Lechosław
authors.initials: L
authors.lastname: Latos-Grażyński
mesh_terms: D001895:Boron / Q000737:chemistry; D056831:Coordination Complexes / Q000737:chemistry; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D011166:Porphyrins / Q000138:chemical synthesis* / Q000737:chemistry; D013876:Thiophenes / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D056831:Coordination Complexes; D011166:Porphyrins; D013876:Thiophenes; D001895:Boron
keywords: anti-aromaticity; aromaticity; subporphyrin; triphyrin