title: Synthesis and Properties of Bis-Porphyrin Molecular Tweezers: Effects of Spacer Flexibility on Binding and Supramolecular Chirogenesis.
abstract: Ditopic binding of various dinitrogen compounds to three bisporphyrin molecular tweezers with spacers of varying conformational rigidity, incorporating the planar enediyne (1), the helical stiff stilbene (2), or the semi-rigid glycoluril motif fused to the porphyrins (3), are compared. Binding constants Ka = 10⁴-10⁶ M(-1) reveal subtle differences between these tweezers, that are discussed in terms of porphyrin dislocation modes. Exciton coupled circular dichroism (ECCD) of complexes with chiral dinitrogen guests provides experimental evidence for the conformational properties of the tweezers. The results are further supported and rationalized by conformational analysis.
authors.affiliation: Department of Chemistry-BMC, Uppsala University, Uppsala S-75123, Sweden. magnus.blom@kemi.uu.se.
authors.forename: Magnus
authors.initials: M
authors.lastname: Blom
authors.affiliation: Department of Chemistry-BMC, Uppsala University, Uppsala S-75123, Sweden. sara.norrehed@raa.se.
authors.forename: Sara
authors.initials: S
authors.lastname: Norrehed
authors.affiliation: Department of Chemistry-BMC, Uppsala University, Uppsala S-75123, Sweden. claes.henrik.andersson@gmail.com.
authors.forename: Claes-Henrik
authors.initials: CH
authors.lastname: Andersson
authors.affiliation: Department of Chemistry-BMC, Uppsala University, Uppsala S-75123, Sweden. hao.huang@angstrom.uu.se.
authors.forename: Hao
authors.initials: H
authors.lastname: Huang
authors.affiliation: Department of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK. light@soton.ac.uk.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Light
authors.affiliation: Department of Chemistry-BMC, Uppsala University, Uppsala S-75123, Sweden. jonas.bergquist@kemi.uu.se.
authors.forename: Jonas
authors.initials: J
authors.lastname: Bergquist
authors.affiliation: Department of Chemistry-BMC, Uppsala University, Uppsala S-75123, Sweden. helena.grennberg@kemi.uu.se.
authors.forename: Helena
authors.initials: H
authors.lastname: Grennberg
authors.affiliation: Department of Chemistry-BMC, Uppsala University, Uppsala S-75123, Sweden. adolf.gogoll@kemi.uu.se.
authors.forename: Adolf
authors.initials: A
authors.lastname: Gogoll
mesh_terms: D002942:Circular Dichroism; D046911:Macromolecular Substances / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D011166:Porphyrins / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D046911:Macromolecular Substances; D011166:Porphyrins
keywords: bisporphyrin tweezers; chirality transfer; chirogenesis; conformational analysis; exciton coupled circular dichroism; host-guest chemistry; metalloporphyrins; porphyrinoids; supramolecular chemistry