Halogen‐Bond‐Assisted Guest Inclusion in a Synthetic Cavity

The confined space inside a self‐assembled cage enhanced halogen bonding (XB) between iodoperfluorocarbons (XB donors) and NO₃^? anions or H₂O molecules (XB acceptors), as confirmed by NMR spectroscopy in solution and by X‐ray crystallography in the solid state. The cavity also bound an XB donor–acceptor pair, C₆F₃I₃ and C₆H₅NMe₂, in a selective pairwise fashion.     

Weak solutions to a hydrodynamic model for semiconductors and relaxation to the drift-diffusion equation

We investigate the relaxation problem for the hydrodynamic isentropic Euler-Poisson system when the momentum relaxation time tends to zero. Very sharp estimates on the solutions, independent of the relaxation time, are obtained and used to establish compactness.     

Halogen bonding and pi...pi stacking control reactivity in the solid state

The halogen bonding and the pi...pi stacking interactions induce the noncovalent self-assembly of modules into photoreactive supramolecular architecture. The pi...pi interaction pre-organizes the template, and the halogen bonding aligns the olefins to conform to the topochemical principle for photoreaction. The UV irradiation of the crystal resulted in a cyclization product with quantitative yield and stereospecificity.     

BODIPY Dyes Bearing Multibranched Fluorinated Chains: Synthesis,Structural, and Spectroscopic Studies

A small series of boron-dipyrromethene (BODIPY) dyes, characterized by the presence of multibranched fluorinated residues, were designed and synthesized. The dyes differ in both the position (para-perfluoroalkoxy-substituted phenyl ring or boron functionalization) and number of magnetically equivalent fluorine atoms (27 or 54 fluorine atoms per molecule). Photophysical and crystallographic characterization of the synthesized BODIPYs was carried out to evaluate the effect of the presence of highly fluorinated moieties on the optical and morphological properties of such compounds.     

An aromatic coupling motif for two-dimensional supramolecular architectures

We show, using scanning tunneling microscopy, how a coupling motif based on self-complementary helical aromatic units is able to drive the formation of a chiral porous supramolecular network and chains based on lateral aromatic interactions in two dimensions.     

Combining halogen bonds and hydrogen bonds in the modular assembly of heteromeric infinite 1-D chains

Hydrogen bonds and halogen bonds operate in concert in the directed assembly of infinite 1-D chains in binary co-crystals of iodine iso-nicotinamide (2 : 2), 1 and tetrafluorodiiodobenzene iso-nicotinamide (1 : 2) 2.     

Superfluorinated Ionic Liquid Crystals Based on Supramolecular,Halogen‐Bonded Anions

Unconventional ionic liquid crystals in which the liquid crystallinity is enabled by halogen‐bonded supramolecular anions [C_nF_{2 n+1}‐I???I???I‐C_nF_{2 n+1}]^? are reported. The material system is unique in many ways, demonstrating for the first time 1) ionic, halogen‐bonded liquid crystals, and 2) imidazolium‐based ionic liquid crystals in which the occurrence of liquid crystallinity is not driven by the alkyl chains of the cation.     

Molecular association in 2-bromo-2-chloro-1,1,1-trifluoroethane (Halothane)

Intermolecular interactions and the role of fluorine substitution have been investigated for a halogenated-ethane anesthetic. 2-Bromo-2-chloro-1,1,1-trifluoroethane, BrClCHCF₃ (Halothane), has been in situ pressure frozen in a diamond anvil cell and its structure determined by single-crystal X-ray diffraction at 1.85(5) GPa/296 K. Crystal is triclinic, space group . In this racemic structure the enantiomorphic molecules are substitutionally disordered at the same general positions in that way that bromine and chlorine atoms occupy the same site at the 50:50 ratio. Despite the fact that only the Br and Cl atoms are disordered, the crystal packing is dominated by halogen?halogen and halogen?hydrogen interactions. This X-ray diffraction study provides structural explanation of considerably increased vapor pressure of Halothane compared to its hydrogenated analogue.     

Improved methodology for the preparation of water-soluble maleimide-functionalized small gold nanoparticles

Improved methodology to prepare maleimide-functionalized, water-soluble, small (<3 nm) gold nanoparticles using a retro-Diels-Alder strategy that we developed for similar organic-soluble AuNP's is described. Importantly, our results suggest that a recent paper by Zhu, Waengler, Lennox, and Schirrmacher describing a similar strategy gave results inconsistent with the formation of the titled maleimide-modified AuNP (Zhu, J.; Waengler, C.; Lennox, R. B.; Schirrmacher, R. Langmuir2012, 28, 5508) as the major product, but consistent with the major product being an adduct derived from the hydrolysis of maleimide formed under the conditions used for the required deprotection of the maleimide. Our methodology provides an efficient and accessible route to pure maleimide-modified small AuNP's that circumvents the formation of the hydrolysis product. The maleimide-modified small AuNP's are versatile because they are soluble in water and in a wide range of organic solvents and their reactivity can now be properly exploited as a reactive moiety in Michael addition for bioconjugation studies in aqueous solution.