title: Time-Dependent Solid State Polymorphism of a Series of Donor-Acceptor Dyads.
abstract: In order to exploit the use of favorable electrostatic interactions between aromatic units in directing the assembly of donor-acceptor (D-A) dyads, the present work examines the ability of conjugated aromatic D-A dyads with symmetric side chains to exhibit solid-state polymorphism as a function of time during the solid formation process. Four such dyads were synthesized and their packing in the solid-state from either slower (10-20 days) or faster (1-2 days) evaporation from solvent was investigated using single crystal X-ray analysis and powder X-ray diffraction. Two of the dyads exhibited tail-to-tail (A-A) packing upon slower evaporation from solvent and head-to-tail (D-A) packing upon faster evaporation from solvent. A combination of single crystal analysis and XRD patterns were used to create models wherein a packing model for the other two dyads is proposed. Our findings suggest that while side chain interactions in asymmetric aromatic dyads can play an important role in enforcing segregated D-A dyad assembly, slowly evaporating symmetrically substituted aromatic dyads allows for favorable electrostatic interactions between the aromatic moieties to facilitate the organization of the dyads in the solid-state.
authors.affiliation: The University of Texas at Austin. Department of Chemistry. Welch Hall 2.204, 105 E. 24 St. STOP A3500. Austin, TX 78712.
authors.forename: Cameron
authors.initials: C
authors.lastname: Peebles
authors.affiliation: The University of Texas at Austin. Department of Chemistry. Welch Hall 2.204, 105 E. 24 St. STOP A3500. Austin, TX 78712.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Alvey
authors.affiliation: The University of Texas at Austin. Department of Chemistry. Welch Hall 2.204, 105 E. 24 St. STOP A3500. Austin, TX 78712.
authors.forename: Vincent
authors.initials: V
authors.lastname: Lynch
authors.affiliation: The University of Texas at Austin. Department of Chemistry. Welch Hall 2.204, 105 E. 24 St. STOP A3500. Austin, TX 78712.
authors.forename: Brent L
authors.initials: BL
authors.lastname: Iverson