title: Synthesis and conformational characteristics of alkyl-substituted pillar[5]arenes.
abstract: A series of pillar[5]arene derivatives with alkyl groups of different length were synthesized. The new alkyl-substituted pillar[5]arene derivatives 1,4-bis(ethoxy)pillar[5]arene (C2), 1,4-bis(propoxy)pillar[5]arene (C3), 1,4-bis(butoxy)pillar[5]arene (C4), 1,4-bis(pentyloxy)pillar[5]arene (C5), 1,4-bis(hexyloxy)pillar[5]arene (C6), and 1,4-bis(dodecanoxy)pillar[5]arene (C12) were obtained by Lewis acid-catalyzed condensation of dialkoxybenzene monomers with paraformaldehyde. The conformational characteristics of the pillar[5]arene derivatives were investigated by dynamic (1)H NMR measurements. When the alkyl substituents were bulkier than methyl groups, the rotation of phenolic units in the pillar[5]arenes was suppressed and their conformation was immobilized. As their length increased, the alkyl substituents packed at the upper and lower rims and thus lowered the conformational freedom of the pillar[5]arenes.
authors.affiliation: Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan. ogoshi@t.kanazawa-u.ac.jp
authors.forename: Tomoki
authors.initials: T
authors.lastname: Ogoshi
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kitajima
authors.forename: Takamichi
authors.initials: T
authors.lastname: Aoki
authors.forename: Shuhei
authors.initials: S
authors.lastname: Fujinami
authors.forename: Tada-Aki
authors.initials: TA
authors.lastname: Yamagishi
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Nakamoto
mesh_terms: D047250:Calixarenes / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D013237:Stereoisomerism
chemical_list: D047250:Calixarenes