Andrew J. Peloquin

Synthesis of 1,3-Diphenyl-6-alkyl/aryl-Substituted Fulvene Chromophores: Observation of π–π Interactions in a 6-Pyrene-Substituted 1,3-Diphenylfulvene

The synthesis, structural, and electronic properties of nine 1,3-diphenyl-6-alkyl/aryl substituted pentafulvenes were studied. Pyrene ring π-π interactions were revealed from analysis of the experimental crystal packing of 1,3-diphenyl-6-(1-pyrene)fulvene and supporting DFT calculations. Photophysical properties derived from UV-vis and fluorescence emission measurements demonstrated tunable and low HOMO-LUMO band gaps for the series. The presented results point to a model synthetic approach for incorporation of extended π systems and donor-π-acceptor groups for fulvene-based electronic materials.

Anomalous macromolecular assembly of partially fluorinated polyhedral oligomeric silsesquioxanes

Fluorinated polyhedral oligomeric silsesquioxane (F-POSS) compounds were prepared by employing a facile, corner-capping methodology. Using this modular approach, fluorocarbons with varying degree of fluorine content and architecture were installed on the POSS cage of a partially condensed trisilanol. The melting properties of the F-POSS derivatives showed various influence by Si…F contacts via intermolecular packing assembly. All F-POSS compounds were characterized by 1H, 13C, 19F, and 29Si NMR spectrometry, X-ray crystallography, thermal and elemental combustion analysis.

Fluorinated Polyhedral Oligosilsesquioxane Surfaces and Superhydrophobicity

Fluorinated compounds are a logical choice for hydrophobic applications owing to their generally low surface energy. Polyhedral molecules may also improve hydrophobicity by increasing material surface roughness. There have been many recent attempts to synthesize and characterize various types of fluorinated polyhedra. These reports include the fluorination or fluoroalkylation of C60 [1,2]. Unfortunately, C60F48 (fluorinated buckminsterfullerene) cannot be used as a hydrophobic material, since it is metastable and is hydrolyzed by water [3]. However, the perfluorocarborane species, perfluoro-deca-β-methyl-para-carborane, shows remarkable hydrolytic and oxidative stability [4]. Fluorinated carbon nanotubes and nanofibers have also been produced [5]. Many of these fluorinated polyhedral compounds may be useful in hydrophobic applications, but they are generally hazardous to prepare, require air and moisture sensitive manipulations, and have limited economies of scale. For these reasons, alternative fluorinated polyhedra, such as Polyhedral Oligomeric SilSesquioxanes (POS) are highly desired (Figure 6.1).

Crystal structure of chlorido­(dimethyl sulfoxide-κS)bis­[4-(pyridin-2-yl)benzaldehyde-κ3C2,N]iridium(III) aceto­nitrile monosolvate

The title iridium(III) complex crystallizes as a acetonitrile monosolvate and has the IrIII atom in a distorted octahedral coordination within a C2N2ClS coordination set.