Representing Structural Isomer Effects in a Coarse-Grain Model of Poly(Ether Ketone Ketone).

Carbon-fiber composites with thermoplastic matrices offer many processing and performance benefits in aerospace applications, but the long relaxation times of polymers make it difficult to predict how the structure of the matrix depends on its chemistry and how it was processed. Coarse-grained models of polymers can enable access to these long-time dynamics, but can have limited applicability outside the systems and state points that they are validated against. Here we develop and validate a minimal coarse-grained model of the aerospace thermoplastic poly(etherketoneketone) (PEKK).

Supramolecular Interactions of Group VI Metal Carbonyl Complexes: The Facilitating Role of 1,3-Bis( p-isocyanophenyl)urea.

An investigation of supramolecular phenomena involving zerovalent transition metal complexes was facilitated by the production of the ditopic isocyanide ligand 1,3-bis( p-isocyanophenyl)urea, which was synthesized via substoichiometric phosgenation of 4-isocyanophenylamine and used to coordinate group VI metal carbonyl fragments. The resulting binuclear organometallic complexes were observed to pack into ladder-like anisotropic arrays in the solid state. Crystallographic and computational evidence suggests that this packing motif can be attributed to a combination of intermolecular π-π and urea-π interactions.

Ab Initio Studies of Exciton Interactions of Cy5 Dyes.

The excited state properties of cyanine dyes and the orientations of their aggregates were studied using density functional theory (DFT). The effects of exchange-correlation functional and solvent model on the absorption spectrum of Cy5 was investigated. Using the 6-31+G(d,p) basis set and B3LYP exchange-correlation functional with IEF-PCM (water) solvent, the predicted spectrum achieved a maximum absorbance within 0.