title: Synthesis, structure, and properties of α,β-linked oligothiazoles with controlled sequence.
abstract: α,β-Linked oligothiazoles with head-to-tail connectivity are presented as a new family of helical scaffolds. Combinations of palladium-catalyzed cross-coupling reactions at the 5- and 4-positions of 2-phenylthiazole led to the synthesis of oligo(2-phenylthiazoles) with ortho linkages with a variety of defined sequences. The secondary structures of the α,β-linked oligo(2-phenylthiazoles) showed a clear dependence on their sequences. X-ray crystallography of the trimer, tetramer, and hexamer with head-to-tail connection revealed the formation of a helical structure, which was stabilized by a combination of intramolecular forces, including interheteroatom (S⋅⋅⋅N), CH-π, and π-π interactions. The introduction of a chiral end-group successfully led to the induction of chirality into the helical conformations. Programmable sequences for controlled geometries and photofunctions have been demonstrated through the manifold connection pathways in α,β-linked oligothiazoles.
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan). ntaku@ms.naist.jp.
authors.forename: Takuya
authors.initials: T
authors.lastname: Nakashima
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Imamura
authors.forename: Kyohei
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kimura
authors.forename: Shohei
authors.initials: S
authors.lastname: Katao
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Hashimoto
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kawai
keywords: helical structures; heteroaromatics; oligomerization; photochemistry; supramolecular chemistry