title: Supramolecular Gelation of Rigid Triangular Macrocycles through Rings of Multiple C-H···O Interactions Acting Cooperatively.
abstract: When equimolar solutions of the enantiomeric naphthalenediimide-based highly rigid triangles R-Δ and S-Δ in ClCH2CH2Cl are mixed, the racemate rac-Δ forms an organogel that is composed of interwoven fibers, resulting from the columnar stacking of the triangles in an alternating R-Δ/S-Δ fashion. Under identical conditions, the pure enantiomers do not form organogels. Density functional theory calculations reveal that the racemic RS dimer is more stable than the RR dimer as a result of the enantiomeric relationship between R-Δ and S-Δ, allowing them to act as two complementary rings comprised of 12 [C-H···O] interactions with an unprecedented and uninterrupted circular ADDAADDAADDA·DAADDAADDAAD alignment of hydrogen bond donors (D) and acceptors (A), in contrast with the square-wave manner in which the RR dimer forms a complementary yet interrupted ADADAD·DADADA circular sequence of six longer [C-H···O] hydrogen bonds. It follows that gelation is favored by weak interactions acting cooperatively in rings under precise stereoelectronic control.
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Zhichang
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Junling
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208-3113, United States.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.|Center for Bio-inspired Energy Science, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Yilei
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Siva Krishna Mohan
authors.initials: SK
authors.lastname: Nalluri
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Yuping
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Avik
authors.initials: A
authors.lastname: Samanta
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.|Department of Materials Science and Engineering, Northwestern University , 2220 Campus Drive, Evanston, Illinois 60208-3113, United States.
authors.forename: Chad A
authors.initials: CA
authors.lastname: Mirkin
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.|Center for Bio-inspired Energy Science, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: George C
authors.initials: GC
authors.lastname: Schatz
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: J Fraser
authors.initials: JF
authors.lastname: Stoddart