title: Synthesis of cyclic hexameric porphyrin arrays. Anchors for surface immobilization and columnar self-assembly.
abstract: To investigate new architectures for the self-assembly of multiporphyrin arrays, a one-flask synthesis of a shape-persistent cyclic hexameric array of porphyrins was exploited to prepare six derivatives bearing diverse pendant groups. The new arrays contain 6-12 carboxylic acid groups, 12 amidino groups, 6 thiol groups, or 6 thiol groups and 6 carboxylic acid groups in protected form (S-acetylthio, TMS-ethyl, TMS-ethoxycarbonyl). The arrays contain alternating Zn and free base (Fb) porphyrins or all Zn porphyrins. The one-flask synthesis entails a template-directed, Pd-mediated coupling of a p/p'-substituted diethynyl Zn porphyrin and a m/m'-substituted diiodo Fb porphyrin. The porphyrin building blocks (trans-A(2)B(2), trans-AB(2)C) contain the protected pendant groups at nonlinking meso positions. A self-assembled monolayer (SAM) of a Zn(3)Fb(3) cyclic hexamer containing one thiol group on each porphyrin was prepared on a gold electrode and the surface-immobilized architecture was examined electrochemically. Together, the work reported herein provides cyclic hexameric porphyrin arrays for studies of self-assembly in solution or on surfaces.
authors.affiliation: Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA.
authors.forename: Kin-ya
authors.initials: KY
authors.lastname: Tomizaki
authors.forename: Lianhe
authors.initials: L
authors.lastname: Yu
authors.forename: Lingyun
authors.initials: L
authors.lastname: Wei
authors.forename: David F
authors.initials: DF
authors.lastname: Bocian
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Lindsey