Non-benzenoid polycyclic aromatic hydrocarbons (PAHs) have received a lot of attention because of their unique optical, electronic, and magnetic properties, but their synthesis remains challenging. Herein, we report a non-benzenoid isomer of peri-tetracene, diazulenorubicene (DAR), with two sets of 5/7/5 membered rings synthesized by a (3+2) annulation reaction. Compared with the precursor containing only 5/7 membered rings, the newly formed five membered rings switch the aromaticity of the original heptagon/pentagon from antiaromatic/aromatic to non-aromatic/antiaromatic respectively, modify the intermolecular packing modes, and lower the LUMO levels.
View Article and Find Full Text PDFIt is vital to differentiate catalytic properties between cationic and metallic single atoms at the atomic level. To achieve this, we fabricated well-defined cationic Ni atoms snugged in and metallic Ni atoms supported on monolayered CuO. The Ni cations are chemically inert for CO adsorption even at 70 K but highly active toward O dissociation at room temperature.
View Article and Find Full Text PDFSodium chlorides in non-1:1 stoichiometry are counterintuitive but recently their existence has been found under the high pressure condition or in the confined space between graphene sheets. Here the direct observation of the formation of Na Cl nanoclusters, a stable magic-number structure, is reported on an Ir(111) surface using scanning tunneling microscopy and noncontact atomic force microscopy. The stability of Na Cl nanoclusters in the free and adsorbed state is corroborated by density functional theory calculations.
View Article and Find Full Text PDFThe involvement of metal atoms in molecular assemblies has enriched the structural and functional diversity of two-dimensional supramolecular networks, where metal atoms are incorporated into the architecture coordination or ionic bonding. Here we present a temperature-variable study of the self-assembly of the 1,3,5-tribromobenzene (TriBB) molecule on Cu(111) that reveals the involvement of nonbonded adatoms in the molecular matrix. By means of scanning tunneling microscopy and noncontact atomic force microscopy, we demonstrate the molecular-level details of a phase transition of TriBB assembly from the close-packed to porous honeycomb structures at 78 K.
View Article and Find Full Text PDFRationally designed halogenated hydrocarbons are widely used building blocks to fabricate covalent-bonded carbon nanostructures on surfaces through a reaction pathway involving generation and dissociation of organometallic intermediates and irreversible covalent bond formation. Here, we provide a comprehensive picture of the on-surface-assisted homocoupling reaction of 1,3-bis(2-bromoethynyl)benzene on Au(111), aiming for the synthesis of graphdiyne nanostructures. Submolecular resolution scanning tunneling microscopy and noncontact atomic force microscopy observations identify the organometallic intermediates and their self-assemblies formed in the dehalogenation process.
View Article and Find Full Text PDFConductive polymers are of great importance in a variety of chemistry-related disciplines and applications. The recently developed bottom-up on-surface synthesis strategy provides us with opportunities for the fabrication of various nanostructures in a flexible and facile manner, which could be investigated by high-resolution microscopic techniques in real space. Herein, we designed and synthesized molecular precursors functionalized with benzal gem-dibromomethyl groups.
View Article and Find Full Text PDFThe carbon-carbon triple bond (-C≡C-) is an elementary constituent for the construction of conjugated molecular wires and carbon allotropes such as carbyne and graphyne. Here we describe a general approach to in situ synthesize -C≡C- bond on Cu(111) surface via homo-coupling of the trichloromethyl groups, enabling the fabrication of individual and arrays of poly(p-phenylene ethynylene) molecular wires. Scanning tunneling spectroscopy reveals a delocalized electronic state extending along these molecular wires, whose structure is unraveled by atomically resolved images of scanning tunneling microscopy and noncontact atomic force microscopy.
View Article and Find Full Text PDFOn-surface synthesis shows significant potential in constructing novel nanostructures/nanomaterials, which has been intensely studied in recent years. The formation of acetylenic scaffolds provides an important route to the fabrication of emerging carbon nanostructures, including carbyne, graphyne, and graphdiyne, which feature chemically vulnerable sp-hybridized carbon atoms. Herein, we designed and synthesized a tribromomethyl-substituted compound.
View Article and Find Full Text PDFEmbedding non-hexagonal rings into sp-hybridized carbon networks is considered a promising strategy to enrich the family of low-dimensional graphenic structures. However, non-hexagonal rings are energetically unstable compared to the hexagonal counterparts, making it challenging to embed non-hexagonal rings into carbon-based nanostructures in a controllable manner. Here, we report an on-surface synthesis of graphene-like nanoribbons with periodically embedded four- and eight-membered rings.
View Article and Find Full Text PDFZhonghua Gan Zang Bing Za Zhi
July 2015
Objective: To explore the clinical significance of high-sensitivity C-reactive protein (hsCRP) in the development of chronic hepatitis B (CHB).
Methods: A total of 182 patients with untreated CHB and 50 healthy individuals (controls) participated in the study. Correlation analysis was performed to determine the association of serum hs-CRP with the age,sex,medical history,serum hepatitis B virus (HBV) DNA, liver function parameters,liver stiffness measure (LSM) and hepatic fibrosis; in addition, correlation analysis was carried out for the associations of degree of liver damage with grade of hepatic fibrosis, LSM and the serum levels of hs-CRP.
Background/aims: The aim of this study was to explore the potential role of serum high-sensitivity C-reactive protein (hs-CRP) in the pathogenic process of chronic hepatitis B.
Methodology: A total of 380 patients with chronic hepatitis B were included in this study. All patients received the concentrations of serum hs-CRP, Hepatitis B sero-markers, serum HBV-DNA loads, liver function parameters and liver stiffness were measured, and in which 172 patients undertaken liver biopsy and immunohistochemistry analysis.