GGA-based analysis of the metformin adsorption on BN nanotubes

Density functional theory (DFT) studies are done to investigate structural and electronic properties of (5,5) chirality single walls boron nitride nanotubes (BNNTs) in the armchair model interacting with metformin (MF) on the surface and ends. Our calculations consider the exchange-correlation energies with the Hamprecht–Cohen–Tozer–Handy functional within the generalized gradient approximation (HCTH-GGA) and the double polarized DNP base function. The geometry optimization follows the minimum energy criterion for all six geometries we have considered. Results show that the MF is adsorbed through the groups NH₂–NH at one end of the nanotube. The system polarity is increased which indicates the possible dispersion and solubility. Moreover the interaction between these species induces an increase in the chemical reactivity of the order of 0.42 eV. Meanwhile the solvation in water keeps the semiconductor characteristics of both nanotube and MF. The work function of the BNNT-MF is drastically reduced respect to the pristine system when the BN nanotube is doped at its surface and ends with carbon. This means that the functionalized BN nanotube facilitates conditions to improve field emission.     

GROUP 13 CLUSTER CHEMISTRY: ORGANOGALLIUM AND -INDIUM SUBHALIDES AND RADICALS

Organogallium or-indium subhalides are easily available by the halogenation of the corresponding tetrahedral clusters E ₄ [C(SiMe ₃ ) ₃ ] ₄ . Three types of compounds are formed that retain the tetrahedral arrangement of In atoms or give chains with two or three Ga or In atoms connected by E─E bonds. These subhalides are suitable starting compounds for the synthesis of secondary products containing the elements in low oxidation states. Carboxylato derivatives or transition metal complexes were obtained on such a route. A persistent radical anion was formed on electron transfer to Ga ₉ (CMe ₃ ) ₉ .     

Optical absorption of zigzag single walled boron nitride nanotubes in axial magnetic field

We have investigated the effect of axial magnetic field on the band structure, dipole matrix elements and absorption spectrum in different energy ranges, using tight binding approximation. It is found that magnetic field breaks the degeneracy in the band structure and creates new allowed transitions in the dipole matrix which leads to creation of new peaks in the absorption spectrum. It is found that, unlike to CNTs which show metallic–semiconductor transition, the BNNTs remain semiconductor in any magnetic field strength. By calculation the diameter dependence of peak positions, we found that the positions of three first peaks in the lower energy region (E <5.3 eV) are proportional to n⁻². In the middle energy region (7 < E < 7.5 eV) all (n, 0) zigzag BNNTs, with even and odd nanotube index, have two distinct peaks in the absence of magnetic field which these peaks may be used to identify zigzag BNNTs from other tube chiralities. For odd (even) tubes, in the middle energy region, applying the magnetic field leads to splitting of these two peaks into three (five) distinct peaks.     

Amorphous carbon nitride as an alternative electrode material in electroanalysis: Simultaneous determination of dopamine and ascorbic acid

Boron-doped diamond (BDD) films are excellent electrode materials, whose electrochemical activity for some analytes can be tuned by controlling their surface termination, most commonly either to predominantly hydrogen or oxygen. This tuning can be accomplished by e.g. suitable cathodic or anodic electrochemical pretreatments. Recently, it has been shown that amorphous carbon nitride (a-CN_x) films may present electrochemical characteristics similar to those of BDD, including the influence of surface termination on their electrochemical activity toward some analytes. In this work, we report for the first time a complete electroanalytical method using an a-CN_x electrode. Thus, an a-CN_x film deposited on a stainless steel foil by DC magnetron sputtering is proposed as an alternative electrode for the simultaneous determination of dopamine (DA) and ascorbic acid (AA) in synthetic biological samples by square-wave voltammetry. The obtained results are compared with those attained using a BDD electrode. For both electrodes, a same anodic pretreatment in 0.1 mol L⁻¹ KOH was necessary to attain an adequate and equivalent separation of the DA and AA oxidation potential peaks of about 330 mV. The detection limits obtained for the simultaneous determination of these analytes using the a-CN_x electrode were 0.0656 μmol L⁻¹ for DA and 1.05 μmol L⁻¹ for AA, whereas with the BDD electrode these values were 0.283 μmol L⁻¹ and 0.968 μmol L⁻¹, respectively. Furthermore, the results obtained in the analysis of the analytes in synthetic biological samples were satisfactory, attesting the potential application of the a-CN_x electrode in electroanalysis.     

Indium-Mediated Synthesis of Homoallyl Alcohols in the Aqueous Phase

The indium-mediated Barbier-type allylation reaction of aldehydes with allyl bromide, which gives corresponding homoallyl alcohols, was investigated. The reaction medium and the effects of substituents were discussed in detail. The results showed that various aldehydes, including aromatic, heterocyclic, and aliphatic aldehydes, with different substituents could all react well with excellent yields of 91–97% in aqueous tetrahydrofuran at room temperature within about 1 h.

Micron Particles of AlN/Al: Efficient,Novel, and Reusable Heterogeneous Catalyst for the Synthesis of Bis(indolyl)methanes

The present work introduces for the first time the catalytic utility of micron particulate aluminium nitride (AlN/Al) as a novel and reusable heterogeneous catalyst for the synthesis of bis(indolyl)methanes involving the electrophilic substitution of indoles on aldehydes. The catalyst is recyclable and works without any significant change in its catalytic activity.     

Mild and Efficient Deoxygenation of Sulfoxides with a WCl6/Indium System

Dialkyl, diaryl, and aryl alkyl sulfoxides can be rapidly converted to the corresponding sulfides with a WCl₆/In system in excellent yields under mild conditions.     

Convenient and Scalable Synthesis of 2,3-Dihydroquinazolin-4(1H)-one Derivatives and Their Anticancer Activities

An efficient and mild InBr₃-catalyzed approach to synthesize 2,3-dihydroquinazolin-4(1H)-one derivatives (3a–3aa) has been developed. Notably, all the products were isolated by recrystallization and the reaction is accessible on a gram scale. Moreover, the reactions only require 10–60 min. All the synthesized compounds were evaluated for their in vitro anticancer activity against four human cancer cell lines.