title: Phenylene-Bridged Core-Modified Planar Aromatic Octaphyrin: Aromaticity, Photophysical and Anion Receptor Properties.
abstract: The synthesis of a planar expanded meso porphyrin with an intramolecular para-phenylene-bridged core is reported. The planarity of the octaphyrin macrocycle was confirmed by single-crystal X-ray structural analysis, in which the bridged para-phenylene unit deviated by 27° from the mean macrocyclic plane. Spectroscopic analyses and theoretical calculations suggested that the macrocycle was Hückel aromatic and followed a major [34 π] single-conjugation pathway, which indicated that the bridging para-phenylene unit was not involved in the macrocyclic conjugation. Analysis of the photophysical properties of this system by steady-state absorption/fluorescence spectroscopy and transient absorption spectroscopy revealed moderate enhancement in the parameters of the octaphyrin as compared to its non-bridged octaphyrin congeners, which was attributed to the planarity and rigidity of the macrocycle as imposed by the bridging para-phenylene unit. Preliminary anion-binding studies revealed that the protonated macrocycle bound selectively with chloride ions through N-H⋅⋅⋅Cl hydrogen-bonding interactions.
authors.affiliation: School of Chemical Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, 752-050, Odisha, India.
authors.forename: Ganesan
authors.initials: G
authors.lastname: Karthik
authors.affiliation: Department of Chemistry, Yonsei University, Shinchon-dong 134, Seodaemoon-gu, Seoul, 120-749, Korea.
authors.forename: Won-Young
authors.initials: WY
authors.lastname: Cha
authors.affiliation: School of Chemical Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, 752-050, Odisha, India.
authors.forename: Arindam
authors.initials: A
authors.lastname: Ghosh
authors.affiliation: Department of Chemistry, Yonsei University, Shinchon-dong 134, Seodaemoon-gu, Seoul, 120-749, Korea.
authors.forename: Taeyeon
authors.initials: T
authors.lastname: Kim
authors.affiliation: School of Chemical Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, 752-050, Odisha, India.
authors.forename: A
authors.initials: A
authors.lastname: Srinivasan
authors.affiliation: Department of Chemistry, Yonsei University, Shinchon-dong 134, Seodaemoon-gu, Seoul, 120-749, Korea. dongho@yonsei.ac.kr.
authors.forename: Dongho
authors.initials: D
authors.lastname: Kim
authors.affiliation: School of Chemical Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, 752-050, Odisha, India. tkc@niser.ac.in.
authors.forename: Tavarekere K
authors.initials: TK
authors.lastname: Chandrashekar
mesh_terms: D000838:Anions / Q000737:chemistry; D006860:Hydrogen Bonding; D015394:Molecular Structure; D055668:Photochemical Processes; D011166:Porphyrins / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000838:Anions; D011166:Porphyrins
keywords: aromaticity; molecular bridges; octaphyrin; porphyrinoids; receptors