Combination Of Imidazole Research Articles

Particleboards Bonded by an Imidazole-Based Adhesive System.

Particleboards with different combinations of the adhesive material imidazole, citric acid, and sorbitol were produced. Softwood sawdust from a Swedish sawmill was mixed with an aqueous solution of the chemicals and then dried to 0% moisture content prior to pressing. The boards were pressed to a target density of 700 kg m-3 at either 200 °C or 220 °C for 10 min. The hygroscopic and mechanical properties of the boards were clearly better at 220 °C than 200 °C for all used chemical combinations. A combination of imidazole (14.4 wt%) and citric acid (11.3 wt%) led to the best results, where the thickness swelling after 24 h of water immersion was 6.3% and the internal bonding strength was 0.57 MPa. The modulus of rupture and modulus of elasticity were 3.3 MPa and 1.1 GPa, respectively. Cyclic accelerated weathering showed exceptional stability with a thickness change after boiling and drying of only 2.1% compared to the initial dry thickness. This study indicates that the presence of imidazole leads to greatly improved hygroscopic properties and good internal bonding strength when used in particleboards.

Collective Quantum Magnetism in Nitrogen-Doped Nanographenes.

The emergence of quantum magnetism in nanographenes provides ample opportunities to fabricate purely organic devices for spintronics and quantum information. Although heteroatom doping is a viable way to engineer the electronic properties of nanographenes, the synthesis of doped nanographenes with collective quantum magnetism remains elusive. Here, a set of nitrogen-doped nanographenes (N-NGs) with atomic precision are fabricated on Au(111) through a combination of imidazole [2+2+2]-cyclotrimerization and cyclodehydrogenation reactions. High-resolution scanning probe microscopy measurements reveal the presence of collective quantum magnetism for nanographenes with three radicals, with spectroscopic features which cannot be captured by mean-field density functional theory calculations but can be well reproduced by Heisenberg spin model calculations. In addition, the mechanism of magnetic exchange interaction of N-NGs has been revealed and compared with their counterparts with pure hydrocarbons. Our findings demonstrate the bottom-up synthesis of atomically precise N-NGs which can be utilized to fabricate low-dimensional extended graphene nanostructures for realizing ordered quantum phases.

Non-Doped Sky-Blue OLEDs Based on Simple Structured AIE Emitters with High Efficiencies at Low Driven Voltages.

Blue organic light-emitting diodes (OLEDs) are necessary for flat-panel display technologies and lighting applications. To make more energy-saving, low-cost and long-lasting OLEDs, efficient materials as well as simple structured devices are in high demand. However, a very limited number of blue OLEDs achieving high stability and color purity have been reported. Herein, three new sky-blue emitters, 1,4,5-triphenyl-2-(4-(1,2,2-triphenylvinyl)phenyl)-1H-imidazole (TPEI), 1-(4-methoxyphenyl)-4,5-diphenyl-2-(4-(1,2,2-triphenylvinyl)phenyl)-1H-imidazole (TPEMeOPhI) and 1-phenyl-2,4,5-tris(4-(1,2,2-triphenylvinyl)phenyl)-1H-imidazole (3TPEI), with a combination of imidazole and tetraphenylethene groups, have been developed. High photoluminescence quantum yields are obtained for these materials. All derivatives have demonstrated aggregation-induced emission (AIE) behavior, excellent thermal stability with high decomposition and glass transition temperatures. Non-doped sky-blue OLEDs with simple structure have been fabricated employing these materials as emitters and realized high efficiencies of 2.41 % (4.92 cd A-1 , 2.70 lm W-1 ), 2.16 (4.33 cd A-1 , 2.59 lm W-1 ) and 3.13 % (6.97 cd A-1 , 4.74 lm W-1 ) for TPEI, TPEMeOPhI and 3TPEI, with small efficiency roll-off. These are among excellent results for molecules constructed from the combination of imidazole and TPE reported so far. The high performance of a 3TPEI-based device shows the promising potential of the combination of imidazole and AIEgen for synthesizing efficient electroluminescent materials for OLED devices.

Structure of nitrogen-doped graphene synthesized by combination of imidazole and melamine solid precursors

Here, we demonstrate the synthesis of nitrogen-doped (N-doped) graphene using imidazole and melamine as two different nitrogen containing aromatic rings carbon precursors. Structure of N-doped graphene was investigated at different temperature (800–1020°C) without changing the precursor quantity. It is observed that higher crystalline N-doped graphene can be obtained from the solid precursors at 1020°C on Cu foil. X-ray photoelectron spectroscopy (XPS) analysis shows interesting features for the N-doped graphene synthesized from mixture of imidazole and melamine. Overall graphitic nitrogen content is enhanced in the graphene layers using the mixture of precursors, attributing better coordination of carbon and nitrogen atoms on Cu catalyst. Our finding shows that the graphitic and pyridinic nitrogen content in graphene lattice can be tuned by combination of two different nitrogen containing organic molecules.

Synthesis and Properties of New Imidazole-Based Organic Fluorescent Small Molecule

A series of phenothiazine (or triphenylamine)-substituted imidazoles were designed and synthesized as new organic fluorescent molecules by multi-step reactions. The relationship of their photoluminescence properties and structure was inves- tigated via UV-Vis, fluorescence and electrochemical analyzer. Their highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) distributions were calculated by density functional theory (DFT) (B3LYP; 6-31G*) calculations. The high fluorescence quantum yields, desirable HOMO levels and high thermal stabilities of products indicated that the combination of imidazole and phenothiazines or triphenylamine is an efficient way to enhance hole transporting ability and fluorescent quantum yield.

Role of peripheral phenanthroline groups in the self-assembly of self-assembled molecular triangles

Self-assembled molecular triangles [Pd3(phen)3(imidazolate)3](NO3)3, 1a and [Pd3(phen)3 (imidazolate)3](PF6)3, 1b are prepared by the combination of imidazole with Pd(phen)(NO3)2 and Pd(phen) (PF6)2, respectively. Imidazole was deprotonated during the complexation reactions and the imidazolate so formed acted as a bis-monodentate bridging ligand to form the bowl-shaped trinuclear architectures of 1a/b. Relative orientation of the imidazolate moieties can be best described as syn,anti,antias observed in the crystal structure of 1b. However, in solution state, slow conformational changes are assumed on the basis of 1HNMR spectral data. The molecular triangles are crafted with three peripheral phen units capable of π−π stacking interactions. Well-fashioned intermolecular π−π interactions are observed in the solid-state, wherein further self-assembly of already self-assembled triangle is observed. Self-assembly of the self-assembled molecular triangle [Pd3(phen)3(imidazolate)3](PF6)3 is observed in the solid-state where the triangular panels are packed by utilizing intermolecular π−π interactions in a chain like fashion.

Highly interlocked anion-bridged supramolecular networks from interrupted imidazole-urea gels.

An imidazole urea displays switchable hydrogelation behaviour that is turned off by metal ion coordination to give anion-bound coordination complex arrays.

The influence of ionic liquids on the fabrication of nonenzymatic glucose electrochemical sensor

Gold nanoparticles (GNPs) embedded in a Bucky gel consisting of carbon nanotubes (CNTs) and ionic liquid (IL) show an excellent electrocatalytic activity to glucose oxidation owing to some synergistic effects among GNPs, CNTs and IL. Each component in such a composite has its specific function while there are complicate interactions among them. Based on this strategy, the use of composite as the modified coating allows the fabrication of a novel nonenzymatic glucose electrochemical sensor, which shows a substantial enhancement in detection sensitivity. This paper centers on the influence of several ILs with various anions and cations as well as alkyl branch lengths on the function of sensor. Based on our results, the performance of the sensor is strongly influenced by ILs. A few conclusions can be drawn. Firstly, an imidazolium cation facilitates both the stability of sensor and the efficiencies of GNPs and CNTs, while the alkyl branch lengths have few effects on the performance of sensor. Secondly, a hydrophilic anion is beneficial to the formation of environment where the direct oxidation of glucose takes place. Thirdly, other anions such as BF4− and PF6− do not matter for imidazolium-based IL. Fourthly, non-imidazolium-based IL militates against the dispersion of CNTs and GNPs in Bucky gel, reducing the detection sensitivity to glucose. Of the ILs studied, the best performance for glucose determination is obtained with an IL mainly benefitted by the combination of imidazole and sulfonate.

Polycyclic N-Heterocyclic Compounds. Part 64: Synthesis of 5-Amino-1,2,6,7-tetrahydrobenzo[f]furo[2,3-c]isoquinolines and Related Compounds. Evaluation of Their Bronchodilator Activity and Effects on Lipoprotein Lipase mRNA Expression

Reaction of 1-(3-cyanopropoxy)-3,4-dihydronaphthalene-2-carbonitriles with potassium tert-butoxide gave 5-amino-1,2,6,7-tetrahydrobenzo[f]furo[2,3-c]isoquinolines via a Truce-Smiles rearrangement. The 5-amino group was transformed to the bromo derivatives which were allowed to react with aliphatic cyclic amines to produce amino derivatives. In contrast, a combination of imidazole and NaH gave a dihydrofuran ring cleaved product, the structure of which was confirmed by X-ray crystallographic analysis. Effects of the newly synthesized compounds on carbamylcholine chloride-induced contractions of trachea and lipoprotein lipase mRNA expression were also evaluated and found one promising bronchodilator.

Propyl gallate increases in vitro antifungal imidazole activity against Candida albicans

We looked at the in vitro effect of an antioxidant, propyl gallate (PG), on the antifungal activity of miconazole sulphosalicylate, econazole sulphosalicylate and ketoconazole against 40 clinical isolates of Candida albicans. The combination of imidazole and PG gave MIC values 10–150 times lower than those of imidazole alone. The optimal conditions for this enhanced activity were pH 6.2–8.0 and a fungal cell concentration lower than 3×10 5 cells/ml. The mechanism of the interaction between imidazole and PG is not known but may be as a result of an effect of PG on the P-450 cytochrome. Theoretically this combination could reduce the side effects of long treatment with imidazoles and lower the risk of resistance to these antifungal drugs.