title: Expanding the registry of aromatic amide foldamers: folding, photochemistry and assembly using diaza-anthracene units.
abstract: The synthesis of various 1,8-diaza-4,5-dialkoxy-2,7-anthracene dicarboxylic acid derivatives and their incorporation into cyclic and helically folded aromatic oligoamides are reported. The ability of the diaza-anthracene monomers to undergo photoaddition or head-to-tail photodimerization was investigated in the solid state and in solution. Quantitative conversion of a monomer diester to the corresponding head-to-tail photodimer could be achieved in the solid state without protection from oxygen. The formation of an emissive excimer between two diaza-anthracene units appended at the end of a helically folded oligomer was demonstrated. Intramolecular photodimerization was not observed in this compound, possibly due to the low thermal stability of the head-to-head photoadduct. A cyclic oligoamide composed of two diaza-anthracene and two pyridine units was shown to adopt a flat conformation and to form columnar stacks in the solid state. Longer, noncyclic oligoamides composed of one or two diaza-anthracene units were shown to adopt helical conformations that exist preferentially as double helical dimers.
authors.affiliation: Université Bordeaux 1-CNRS UMR 5248, Institut Européen de Chimie et Biologie, 2 rue Robert Escarpit, 33607 Pessac Cedex, France.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Berni
authors.forename: Christel
authors.initials: C
authors.lastname: Dolain
authors.forename: Brice
authors.initials: B
authors.lastname: Kauffmann
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Léger
authors.forename: Chuanlang
authors.initials: C
authors.lastname: Zhan
authors.forename: Ivan
authors.initials: I
authors.lastname: Huc
mesh_terms: D000577:Amides / Q000737:chemistry*; D000873:Anthracenes / Q000138:chemical synthesis* / Q000737:chemistry / Q000528:radiation effects; D018360:Crystallography, X-Ray; D003500:Cyclization; D003998:Dicarboxylic Acids / Q000138:chemical synthesis* / Q000737:chemistry / Q000528:radiation effects; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D010777:Photochemistry; D013237:Stereoisomerism; D014466:Ultraviolet Rays
chemical_list: D000577:Amides; D000873:Anthracenes; D003998:Dicarboxylic Acids