Synthesis and antibacterial evaluation of new sulfanyltetrazole derivatives bearing piperidine dithiocarbamate moiety

A series of new alkyl or aryl sulfanyltetrazole derivatives containing dithiocarbamate moiety (5a–6e) were synthesized. The structures of the compounds were characterized by IR, ¹H NMR, ¹³C NMR spectra, and elemental analysis data. The present study examines the antibacterial potential of novel synthetic sulfanyltetrazole compounds against clinically important gram-positive and -negative strains. The results of screening showed that attachment of dithiocarbamate to sulfanyltetrazole derivatives results in enhancement of antibacterial activity. The compound 6d showed the best activity among the tested compounds. Also, the less polar 2,5-disubstituted sulfanyltetrazole regioisomers showed an increased antibacterial activity compared with the corresponding more polar regioisomers.     

The presentation of an approach for estimating the intramolecular hydrogen bond strength in conformational study of β-Aminoacrolein

All the plausible conformations of β-aminoacrolein (AMAC) have been investigated by the Bekes-Lee-Yang-Parr (B3LYP) nonlocal density functional with extended 6-311++G** basis set for studying the stability order of conformers and the various possibilities of intramolecular hydrogen bonding formation. In general the ketoamine (KA) conformers of AMAC, by mean average, are more stable than the corresponding enolimine (EI) and ketoimine (KI) analogues and this stability is mainly due to the π-electron resonance in these conformers that established by NH2 functional group. The contribution of resonance to the stability of chelated KA conformers is about 75.6 kJ/mol, which is greater than that of the hydrogen bond energy (E_HB=35.0 kJ/mol). The relative decreasing order of the various hydrogen bond energies was found to be: O–HN_imine(strong)>N_amine-HO_keto (normal)>N_imine-HO_hydroxyl (weak) > N_imine-HO_keto (weak). Hydrogen bond energies for all systems were obtained from the method that we called related rotamers method (RRM). The topological properties of the electron density contributions for various type of intramolecular hydrogen bond have been analyzed in term of the Bader theory of atoms in molecules (AIM). The results of these calculations support the previous calculations, which obtained by the related rotamer methods.     

Epoxidation of alkenes with molecular oxygen and isobutyraldehyde catalyzed by immobilized vitamin B12 within Al-MCM-41

Vit-B₁₂/ Al-MCM-41 catalyzed successfully the epoxidation either of cis or trans — stilbene with O₂ as oxidant and isobutyraldehyde as co-reductant with 86–98% reactivity and 97–100% selectivity. Other olefins such as norbornene and styrene undergo epoxidation reaction under similar conditions with good to fair selectivity. Details of the reactions will be presented in this article.     

Novel CuFe2O4@SiO2‐OP2O5H magnetic nanoparticles: Preparation,characterization and first catalytic application to the synthesis of 1,8‐dioxo‐octahydroxanthenes

New functionalized magnetic core–shell nanoparticles, CuFe₂O₄@SiO₂‐OP₂O₅H, were prepared by grafting of phosphorus pentoxide on CuFe₂O₄@SiO₂ nanoparticles and characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy‐dispersive X‐ray analysis, inductively coupled plasma optical emission spectrometry and vibrating sample magnetometry. The catalytic activity of CuFe₂O₄@SiO₂‐OP₂O₅H as a novel catalyst was evaluated in the synthesis of 1,8‐dioxo‐octahydroxanthenes under solvent‐free conditions. The results showed that the catalyst has high activity and the desired products are obtained in high yields within short reaction times. The catalyst is readily recovered using magnetic decantation and can be used at least four times without noticeable deterioration in catalytic activity.     

Metal ions exchanged montmorillonite as catalyst for alkylation of benzene with 1-dodecene

Summary About 8.5% of benzene was alkylated with 1-dodecene in the presence of Na⁺-montmorillonite. When the reaction was carried out with montmorillonite exchanged with Mn²⁺, Cu²⁺, Ni²⁺, Zn²⁺ and Fe²⁺ ions as catalyst (M²⁺/mont.), 91 to 95% of 1-dodecene was remarkably converted to a mixture of linear monoalkylbenzenes.     

Radiochromic Hydrogen-Bonded Organic Frameworks for X-ray Detection

Porous materials have been investigated as efficient photochromic platforms for detecting hazardous radiation, while the utilization of hydrogen bonded organic frameworks (HOFs) in this field has remained intact. Herein, two HOFs were synthesized through self-assembly of tetratopic viologen ligand and formic acid (PFC-25, PFC-26), as a new class of “all-organic” radiochromic smart material, opening a gate for HOFs in this field. PFC-26 is active upon both X-ray and UV irradiation, while PFC-25 is only active upon X-ray irradiation. The same building block yet different radiochromic behaviors of PFC-25 and PFC-26 allow us to gain a deep mechanistic understanding of the factors that control the detection specificity. Theoretical and experimental studies reveal that the degree of π-conjugation of viologen ligand is highly related to the threshold energy of triggering a charge transfer, therefore being a vital factor for the particularity of radiochromic materials. Thanks to its convenient processibility, nanoparticle size, and UV silence, PFC-25 can be further fabricated into a portable naked-eye sensor for X-ray detection, which shows obvious color change with the merits of high transmittance contrast, good sensitivity (reproducible dose threshold of 3.5 Gy), and excellent stability. The work exhibits the promising practical potentials of HOF materials in photochromic technology.     

Pseudocapacitive Lithium Storage of Cauliflower-Like CoFe2O4 for Low-Temperature Battery Operation

Binary transition-metal oxides (BTMOs) with hierarchical micro–nano-structures have attracted great interest as potential anode materials for lithium-ion batteries (LIBs). Herein, we report the fabrication of hierarchical cauliflower-like CoFe₂O₄ (cl-CoFe₂O₄) via a facile room-temperature co-precipitation method followed by post-synthetic annealing. The obtained cauliflower structure is constructed by the assembly of microrods, which themselves are composed of small nanoparticles. Such hierarchical micro–nano-structure can promote fast ion transport and stable electrode–electrolyte interfaces. As a result, the cl-CoFe₂O₄ can deliver a high specific capacity (1019.9 mAh g⁻¹ at 0.1 A g⁻¹), excellent rate capability (626.0 mAh g⁻¹ at 5 A g⁻¹), and good cyclability (675.4 mAh g⁻¹ at 4 A g⁻¹ for over 400 cycles) as an anode material for LIBs. Even at low temperatures of 0 °C and −25 °C, the cl-CoFe₂O₄ anode can deliver high capacities of 907.5 and 664.5 mAh g⁻¹ at 100 mA g⁻¹, respectively, indicating its wide operating temperature. More importantly, the full-cell assembled with a commercial LiFePO₄ cathode exhibits a high rate performance (214.2 mAh g⁻¹ at 5000 mA g⁻¹) and an impressive cycling performance (612.7 mAh g⁻¹ over 140 cycles at 300 mA g⁻¹) in the voltage range of 0.5–3.6 V. Kinetic analysis reveals that the electrochemical performance of cl-CoFe₂O₄ is dominated by pseudocapacitive behavior, leading to fast Li⁺ insertion/extraction and good cycling life.     

Highly Substituted Δ3-1,2,3-Triazolines: Solid-State Emitters with Electrofluorochromic Behavior

Highly substituted Δ³-1,2,3-triazolines can be prepared by reaction of triarylvinyl Grignard reagents with functionalized organic azides. The heterocycles are fluorescent in the solid state, and—depending on the substituents—they can display aggregation-induced emission. Upon oxidation, the triazolines form stable radical cations with altered photophysical properties. Therefore, they represent rare examples of solid-state emitters with intrinsic electrofluorochromic behavior.