Preparative-scale synthesis of nonacene

During the last years we have witnessed progressive evolution of preparation of acenes with length up to dodecacene by on-surface synthesis in ultra-high vacuum or generation of acenes up to decacene in solid matrices at low temperatures. While these protocols with very specific conditions produce the acenes in amount of few molecules, the strategies leading to the acenes in large quantities dawdle behind. Only recently and after 70 years of synthetic attempts, heptacene has been prepared in bulk phase. However, the preparative scale synthesis of higher homologues still remains a formidable challenge. Here we report the preparation and characterisation of nonacene and show its excellent thermal and in-time stability.

Bulk phase behavior and interfacial properties of binary mixtures of Lennard-Jones chains and solvent: a Density Functional Theory Study

A Density Functional Theory study is performed to analyze both bulk and interfacial properties of solvent-polymer binary mixtures. The effects of increasing polymer chain length on the bulk phase diagram...

Effect of Alkyl Chain Length on Interfacial Performance of Alkyl Gallates in Supramolecular Oxidation of Soybean Bulk Phase Oil

From an interfacial phenomena standpoint, the effect of length of alkyl chain was evaluated on activities of gallic acid and its alkyl ester derivatives in supramolecular oxidation of stripped soybean oil. The gallic acid molecules (log P = -0.47) with an electron-donating carboxylate anion had a higher scavenging activity against DPPH• than alkyl gallates. Interfacial activities of gallates in emulsion and bulk oil improved as the lengths of the alkyl chain were reached until a critical chain length; after that, further chain length extension causes a decrease in potency. In β-carotene bleaching and Rancimat assays higher inhibitory effect was observed for dodecyl and propyl gallate, respectively. Evaluation of interfacial tension, water content, and droplet size of hydroperoxides reverse micelles in parallel with lipid peroxidation indicated that the inhibitory effect of the alkyl gallates, especially methyl gallate, was significantly better than the gallic acid in the bulk phase oil.

Direct observation of the Mottness and p-d orbital hybridization in epitaxial monolayer α-RuCl3

α-RuCl3, with abundant studies in its bulk phase, has shown the promising potential to approach the two-dimensional Kitaev honeycomb model and to realize the consequential quantum spin liquids. In this material, some ingredients spark off the hunting of quantum spin liquid states: the localized magnetic moments on each Ru3+ ion guaranteed by the Mottness, the Kitaev-type interaction originating from the superexchange path over the p-d bonds, and the nearly two-dimensional nature of the van der Waals coupled honeycomb layers. Here, we worked out the growth art of α-RuCl3 monolayer on highly oriented pyrolytic graphite substrate for the first time, and then studied its electronic structure, particularly the delicate orbital occupations. Through scanning tunneling microscopy and spectroscopy study, the bonding configurations are justified by the features of pronounced t2g-pπ and eg-pσ hybridization, and the Mott nature is unveiled by an ~ 0.6 eV full gap at the Fermi level located in the t2g-pπ level. Our experimental results agree well with the density functional theory calculations of the monolayer system. In accordance with previous theoretical research, the epitaxial monolayer α-RuCl3 system holds high tunability comparing to its bulk phase and provides a novel platform to explore the Kitaev physics.

The Regge limit of AdS3 holographic correlators with heavy states: towards the black hole regime

We examine the Regge limit of holographic 4-point correlation functions in AdS3× S3 involving two heavy and two light operators. In this kinematic regime such correlators can be reconstructed from the bulk phase shift accumulated by the light probe as it traverses the geometry dual to the heavy operator. We work perturbatively — but to arbitrary orders — in the ratio of the heavy operator’s conformal dimension to the dual CFT2’s central charge, thus going beyond the low order results of [1] and [2]. In doing so, we derive all-order relations between the bulk phase shift and the Regge limit OPE data of a class of heavy-light multi-trace operators exchanged in the cross-channel. Furthermore, we analyse two examples for which the relevant 4-point correlators are known explicitly to all orders: firstly the case of heavy operators dual to AdS3 conical defect geometries and secondly the case of non-trivial smooth geometries representing microstates of the two-charge D1-D5 black hole.