Charge transport anisotropy in n-type disk-shaped triphenylene-tris(aroyleneimidazole)s

Two novel n-type disk-shaped molecules containing a triphenylene core and three fused naphthaleneimide imidazole or peryleneimide imidazole "arms" are synthesized and characterized. The n-type charge carrier mobilities of these molecules are evaluated by both field effect transistors and space-charge limited-current measurements, which exhibit drastically different mobility anisotropy. A strong correlation between film morphology and the charge transport behavior is established by X-ray scattering and atomic force microscopic analyses.     

Enhanced stability of Janus nanoparticles by covalent cross-linking of surface ligands

A mercapto derivative of diacetylene was used as the hydrophilic ligand to prepare Janus nanoparticles by using hydrophobic hexanethiolate-protected gold (AuC6, diameter 5 nm) nanoparticles as the starting materials. The amphiphilic surface characters of the Janus nanoparticles were verified by contact angle measurements, as compared to those of the bulk-exchange counterparts where the two types of ligands were distributed rather homogeneously on the nanoparticle surface. Dynamic light scattering studies showed that the Janus nanoparticles formed stable superstructures in various solvent media that were significantly larger than those by the bulk-exchange counterparts. This was ascribed to the amphiphilic characters of the Janus nanoparticles that rendered the particles to behave analogously to conventional surfactant molecules. Notably, because of the close proximity of the diacetylene moieties on the Janus nanoparticle surface, exposure to UV irradiation led to effective covalent cross-linking between the diacetylene moieties of neighboring ligands, as manifested in UV-vis and fluorescence measurements where the emission characteristics of dimers and trimers of diacetylene were rather well-defined, in addition to the monomeric emission. In contrast, for bulk-exchange nanoparticles, no trimer emission could be identified, and the intensity of dimer emission was markedly lower (though the intensity increased with increasing diacetylene coverage on the particle surface) under the otherwise identical experimental conditions. This is largely because the diacetylene ligands were distributed on the entire particle surface, and it was difficult to find a large number of ligands situated closely so that the stringent topochemical principles for the polymerization of diacetylene derivatives could be met. Importantly, the cross-linked Janus nanoparticles were found to exhibit marked enhancement of the structural integrity, which was attributable to the impeded surface diffusion of the thiol ligands on the nanoparticle surface, as manifested in fluorescence measurements of aged nanoparticles.     

The Crystal and Molecular Structure of a Polymorph and a Pseudo-Polymorph of Droperidol

Abstract Crystals of two crystal modifications of droperidol: a hemihydrate (1) and the z polymorph (2), have been isolated and their structure determined using X-ray diffraction methods. Droperidol hemihydrate crystallized in the triclinic space group P − 1, with unit cell parameters a = 6.2842(15), b = 10.1473(8), c = 16.1850(2) ?; α = 102.554(9); β = 91.917(14); γ = 99.316(12)°; V = 991.6(3) ?³, and Z = 2. The droperidol z polymorph crystallized in the monoclinic space group P2₁/c, with unit cell parameters a = 20.0406(8), b = 7.4955(4), c = 12.9733(5) ?; β = 98.089(2)°; V = 1929.39(15) ?³, and Z = 4. In 1 and 2 two molecules of droperidol are joined by two N–H···O hydrogen bonds. The structure of 1 shows a possible additional hydrogen bond linking the two droperidol molecules via the water molecule. Graphical Abstract The crystal and molecular structure of a polymorph and a pseudo-polymorph of droperidol A. Actins, R. Arajs, S. Belakovs, L. Orola, and M. V. Veidis Crystals of two crystal modifications of droperidol: a hemihydrate and the z polymorph have been isolated and their structure determined using single crystal X-ray diffraction methods. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Misenine,a Novel Macrocyclic Alkaloid with an Unusual Skeleton from the Mediterranean Sponge Reniera sp

PolycycJic marine alkaloids containing 3-alkylpyridine or partially reduced 3-alkylpyridine as basic building blocks represent an emerging and intriguing group of bioactive natural products from marine sponges. Since halitoxin,² the first example of this kind of alkaloid, was reported in 1978, many related alkaloids have been discovered from sponges of the order Haplosclerida. All of these alkaloids, in spite of formally exhibiting quite different frameworks, could biogeneticaliy derive from bis-3-alkylpyridine or reduced bis-3-alkylpyridine units. In the last decade, the knowledge of this fascinating group of compounds has increased remarkably. A recent review has exhaustively studied occurrence, distribution, plausible biogenetic origin and relatedness, as well as biological activities, of 3-alkylpyridine derived marine alkaloids.³     

Corrosion behaviour of zinc coated with composite silica layers incorporating poly(amidoamine)-modified graphene oxide

Journal of Solid State Electrochemistry - The aim of the paper is to carry out a detailed investigation of the effect of graphene oxide-poly(amidoamine) (GO-PAMAM) incorporated in silica matrices...