title: Tunable columnar mesophases utilizing C2 symmetric aromatic donor-acceptor complexes.
abstract: Derivatives of relatively electron rich 1,5-dialkoxynaphthalene (Dan) donors and relatively electron deficient 1,4,5,8-naphthalenetetracarboxylic diimide (Ndi) acceptors have been exploited in the folding and self-assembly of a variety of complex molecular systems in solution. Here, we report the use of Dan and Ndi derivatives to direct assembly of extended columns with alternating face-centered stacked structure in the solid state. A variety of 1:1 Dan:Ndi mixtures produced mesophases that were found to be stable over temperature ranges extending up to 110 degrees C. Analysis of these mesophases indicates mixtures with soft/plastic crystal phases and a few mixtures with the thermodynamic properties of true liquid crystals, all composed of alternating donor-acceptor columns within. Importantly, a correspondence was found between the clearing and crystallization points of the mesophase mixtures and the melting/clearing points of the component Ndi and Dan units, respectively. This correspondence enables the predictable tuning of mesophase phase transition temperatures. The study of sterically hindered derivatives led to a set of mixtures in which a dramatic and sudden color change (deep red to yellow) was observed upon crystallization of the mesophase due to a phase separation of the component donor and acceptor units.
authors.affiliation: Department of Chemistry and Biochemistry, The University of Texas at Austin, Texas 78712, USA.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Reczek
authors.forename: Karen R
authors.initials: KR
authors.lastname: Villazor
authors.forename: Vincent
authors.initials: V
authors.lastname: Lynch
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Swager
authors.forename: Brent L
authors.initials: BL
authors.lastname: Iverson
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D004583:Electrons; D007094:Imides / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D008968:Molecular Conformation; D009281:Naphthalenes / Q000737:chemistry*; D044367:Phase Transition; D013816:Thermodynamics; D014961:X-Ray Diffraction
chemical_list: C429685:1,4,5,8-naphthalenetetracarboxylic diimide; D007094:Imides; D009281:Naphthalenes