RESUMEN
This data article describes a detailed synthetic strategy and experimental data for the synthesis of brominated fulvene chromophores as reactive precursors/monomers for conjugated organic materials. Metal-mediated coupling reactions of brominated fulvenes would result in conjugated small molecules or polymers that would find application as organic light emitting diodes (OLEDs) and photovoltaic (PV) applications.
RESUMEN
Gold nanoparticles (GNPs) have a wide range of properties with potential applications in electronics, optics, catalysis, and sensing. In order to demonstrate that dense, stable, and portable samples could be created for these applications, multiple layers of GNPs were assembled via drop casting on glass substrates by layer-by-layer (LBL) techniques. Two cationic polyelectrolytes, poly(diallyldimethylammonium chloride) and polyethyleneimine, one anionic polyelectrolyte, poly(sodium 4-styrene sulfonate), and one neutral polymer, polyvinylpyrrolidone, were combined with four different shapes of GNPs (spherical, rod, triangular prismatic, and octahedral) to prepare thin films. A subset of these polymer nanoparticle combinations were assembled into thin films. Synthesized GNPs were characterized via dynamic light scattering, UV-vis spectroscopy, and transmission electron microscopy and the LBL thin films were characterized using UV-vis spectroscopy and atomic force microscopy. Sensing applications of the nanoparticles in solution and thin films were tested by monitoring the localized surface plasmon resonance of the GNPs. LBL thin films were prepared ranging from 25 to 100 layers with optical densities at plasmon from 0.5 to 3.0. Sensitivity in solutions ranged from 14 to 1002nm/refractive index units (RIU) and films ranged from 18.8 to 135.1nm/RIU suggesting reduced access to the GNPs within the films.
RESUMEN
A new PFCP-based chlorosilane monomer containing a latent reactive fluorine atom was synthesized utilizing a hydrosilylation reaction. This monomer was used to functionalize Stöber silica nanoparticles, or network silicas, and the ability to tailor the properties of the functionalized nanoparticles was investigated by reacting the latent reactive fluorinated alkene with various nucleophiles. In order to model the chemical transformations occuring with the PFCP-functionalized particles, a new PFCP-containing molecular silica was prepared using a hydrosilylation reaction. The molecular silica was designed such that it contained a latent reactive fluorine atom and could also undergo post-synthetic modifications with various nucleophiles. The ability to modify the latent reactive group and tune the properties of the molecular and network silicas was verified by multi-nuclear NMR ((1)H, (13)C, (19)F, and (29)Si), thermal characterizations, and by investigating the hydrophobicity and surface morphology of spin-cast films prepared from the molecular and network silicas.
RESUMEN
The first report of perfluorocyclobutyl (PFCB) aryl ether polymer colloids is presented herein. The biphenyl rings were post-functionalized with chlorosulfonic acid modification in the backbone of the perfluoropolymer, thereby changing the zeta potential (ζ) of the colloids across the pH range (2-12). Self-assembly of the colloids was observed by scanning electron microscopy (SEM) on four separate surfaces which led to different morphological changes for each surface; spherical on Al substrate, clover-like on Cr substrate, flower-like on carbon substrate, and "squalloid" on Si substrate.
RESUMEN
The title compounds, C(66)H(46), (I), and C(66)H(42)F(4), (II), are polyphenylated arylenes synthesized by one-step Diels-Alder cycloaddition reactions. In both structures, all molecules lie on crystallographic inversion centers. In the case of (I), there are two half-molecules present in the asymmetric unit, (IA) and (IB); the geometry of each half-molecule differs principally in the magnitudes of the dihedral angles between mean planes fitted through the central aryl ring and the pendant phenyl rings. The crystal used was a non-merohedral twin, with a refined twin scale factor of 0.460 (8). The dihedral angle between the plane of the central tetrafluorinated ring and the adjacent tetraphenylated ring in (II) is 83.87 (4)°, significantly greater than the dihedral angles of 49.89 (12) and 54.38 (10)° found in the two half-molecules in (IA) and (IB), respectively, and attributed to intermolecular C-H···F hydrogen bonding in (II). Intermolecular C-H···π bonding is found in (I). Two interactions have the C-H bond oriented towards the centroid (Cg) of a butadiene fragment of a phenyl ring; both H···Cg distances are approximately 2.68 Å and the interactions connect adjacent molecules into stacks in the c-axis direction. The composition of the stacks alternates, i.e. (IA)-(IB)-(IA)-(IB) etc. A third, weaker, C-H···π interaction and a phenyl-phenyl close contact connect each end of the long molecular axes of (IB) with an adjacent molecule of (IA) into chains which run perpendicular to the (140) and ( Ì 140) planes. C-H···F interactions in (II) have the most profound influence on the molecular and crystal structure, the main effect of which is the above-mentioned increase in the dihedral angle between the plane of the central tetrafluorinated ring and the adjacent tetraphenylated ring. C-H···F interactions have refined H···F distances of 2.572 (15) and 2.642 (16) Å, with approximate C-H···F angles of 123 and 157°, respectively. These form a hydrogen-bonded ribbon structure which propagates in the b-axis direction.
RESUMEN
New fluorovinylene aromatic ether polymers, possessing dual reactivity, have been successfully prepared via the step-growth polymerization of commercial bis(trifluorovinyl) aromatic ethers and bisphenols.