Electron transfer in proton-hydrogen collisions in dense semi-classical hydrogen plasma

Quantum mechanical calculations have been accomplished to study the dynamics of the reaction: p + H(1s) → H(nlm) + p in dense semi-classical hydrogen plasma. Interactions among the charged particles in plasma are represented by a pseudopotential which takes care of the collective effects at large distances and quantum effect of diffraction at small distances. Various capture cross sections are computed for the incident proton energy lying within 10 to 500 keV by applying a distorted wave method which uses a variationally determined closed-form wave function of hydrogen atom. Moreover, an inclusive study is made to explore the effects of screening of plasma and quantum diffraction on various capture cross sections for a wide range of thermal Debye length and de Broglie wave length. It has been found that various cross sections suffer considerable changes due to varying Debye length and de Broglie wave length.     

Studies on the kinetics and mechanism of redox decomposition of 1,2,6-trinitrotriamminecobalt(III) and 1,2,6-trinitrodiethylenetriaminecobalt(III) complexes in aqueous acid

Summary In aqueous acid media the title complexes undergo decomposition ultimately forming cobalt(II). Detailed analysis of the kinetic data reveals that the reactions proceed in two consecutive stages, the initial step being the faster one. Evidence has been presented that the initial faster step involves aquation releasing one NO ₂ ^– ligand and forming an aquodinitro complex, which subsequently undergoes a slower intramolecular redox decomposition into Co²⁺. Each step, on the other hand, has been found to consist of two concurrent paths,viz. spontaneous and acid catalysed, respectively. Activation parameters corresponding to all these specific rate constants have been evaluated and a plausible mechanism for the overall reaction has been proposed.On leave from Agra College, Agra, India.     

X-ray Crystal Structures of [Et3NH][{(CO)5Mo(P(OCH2CMe2CH2O)O)}2H] and (CO)5Mo{μ-Ph2POPPh2}Mo(CO)5, Two Complexes Derived from the Hydrolysis of Coordinated Chloro-Phosphorous-Donor Ligands

Abstract X-ray crystal structures of [Et₃NH][{(CO)₅Mo(P(OCH₂CMe₂CH₂O)O)}₂H], 3, and (CO)₅Mo{μ-Ph₂POPPh₂}Mo(CO)₅, 2, are reported. Crystallization of 3 occurs in P-1 space group with a = 9.6944(19) ?, b = 10.814(2) ?, c = 19.730(4) ?, α = 94.24(3)°, β = 92.23(3)°, γ = 113.47(3)°, Z = 4. Crystallization of 2 occurs in C2/c space group with a = 10.357(2) ?, b = 20.149(4) ?, c = 17.155(3) ?, α = 90°, β = 97.28(3)°, γ = 90°, Z = 8. Compound 2 is a bimetallic complex with a P–O–P bridging group containing bond distances similar to that of other complexes in which two metal centers are bridged by a single R₂POPR₂ ligand. Compound 3 contains intermolecular hydrogen bonded P–O–H–O–P linkages with bond distances comparable to those seen in similar structures with intramolecular hydrogen bonding suggesting that the distance is a function of the nature of the bond and not affected by the cis arrangement of the ligands about the metal center. Graphical abstract X-ray Crystal Structures of [Et ₃ NH][{(CO) ₅ Mo(P(OCH ₂ CMe ₂ CH ₂ O) O)} ₂ H] and (CO) ₅ Mo{μ-Ph ₂ POPPh ₂ }Mo(CO) ₅ , Two Complexes Derived from the Hydrolysis of Coordinated Chloro-Phosphorous-Donor Ligands Samuel B. Owens Jr., Abha A. Kaisare and Gary M. Gray X-ray crystal structures of [Et₃NH][{(CO)₅Mo(P(OCH₂CMe₂CH₂O)O)}₂H], 3, and (CO)₅Mo{μ-Ph₂POPPh₂}Mo(CO)₅, 2, have been determined.      

Synthesis of aminobenzoxazoles via simple,clean and efficient electrochemical redox reactions

An efficient single step process for the construction of pharmaceutically relevant substituted aminobenzoxazoles have been described in this report. Various electrodes and electrolytes combinations have been carried out to harvest optimum coupling results. The presented CN bond formation reaction methodology has applied for the synthesis of biologically active compounds. This methodology saves reaction steps over traditional functionalization reactions.     

Electron transfer in proton-hydrogen collisions in nonideal classical plasmas

Effects of nonideality of classical plasma on the reaction: p + H(1s) → H(nlm) + p has been investigated by carrying out fully quantum mechanical calculations within the framework of a first-order distorted wave method. Scattering amplitude is calculated conveniently by employing a simple, variationally determined wave function of hydrogen atom embedded in nonideal classical plasma. A detailed study is made on the changes in electron transfer cross sections due to the nonideality of plasma varying from 0 to 4 and the incident proton energy lying between 10 and 500 keV. It has been found that nonideality of plasma causes substantial change in capture cross section.     

Synthesis of non-toxic anticancer active forskolin-indole-triazole conjugates along with their in silico succinate dehydrogenase inhibition studies

Biologically important three different pharmacophores, forskolin, indole and 1,2,3-triazoles are coupled to obtain a hybrid molecule. Here, we described the synthesis of novel series of forskolin-indole-triazole conjugates 5a-5l by using the Cu(I) catalyzed 1,3-dipolar cycloaddition reaction. Furthermore, the biological significance of the synthesized molecules was assessed by in silico and in vitro modes. All the synthesized compounds were evaluated for in vitro anticancer activity against PC-3, MCF-7, MDA-MB-231, COLO-205, HeLa, WRL-68, RAJI, CHANG and RAW-264.7 cell lines. Compound 5g was found to be the most potent in all the tested cell lines (IC₅₀ range 9.6–21.66 μg/ml, except COLO-205), 5a, 5b and 5k were observed to exert its effect only against WRL-68 (IC₅₀ range 27.69–48.18 μg/ml), when compared to parent 3 (IC₅₀ > 100 μg/ml, tested concentrations 10–50 μg/ml) and standard Doxorubicin (IC₅₀ range 0.42–3.16 μg/ml). The most potent compound 5g (MEF₅₀ 0.57) was found non-toxic to human erythrocytes as compared to control (MEF₅₀ 0.60) at tested concentration (50 μg/ml). In silico-based succinate dehydrogenase inhibition showed that the synthesized compounds were having potent binding affinity compared to forskolin. Predictive ADMET and toxicity risk assessment analysis revealed that most of the compounds were complying with the standard limit of Lipinski's rule of five for oral bioavailability.     

Recent advances in continuous flow synthesis of heterocycles

In the current scenario, flow chemistry is emerging as a significant technology in the field of organic synthesis. This miniaturized protocol including microreactors facilitates excellent heat transfer, low solvent wastage, lesser reaction time, a safer environment for reagent handling and appreciable yields of desired products. Thus, this “enabling technology” has a great scope in the synthesis and preparation of a variety of heterocycles that require toxic reagents as starting materials. This review discusses the recent advances (2020–2021) in continuous flow strategy for synthesis and derivatization of variety of heterocyclic entities, of different ring size, using different approaches. This also highlights the advantages of different combined techniques like Microwave assisted heating, electrochemical flow cell, LED light source, NMR and FT-IR analysis, etc., that enables utilization of various mechanisms and real-time monitoring of reactions leading to improved results.

Graphic abstract

     

Enhanced infrared to visible upconversion emission in Er3+ doped phosphate glass: Role of silver nanoparticles

Phosphate glasses with compositions (59.5–x)P₂O₅–MgO–xAgCl–0.5Er₂O₃ (0.0≤x≤1.5 mol%) containing fixed concentration of Er³⁺ ion with and without silver nanoparticles (NPs) are prepared using melt quenching technique. The amorphous nature of the glass is confirmed using the X-ray diffraction method. The homogeneous distribution of spherical Ag NPs (average size ～37 nm) in the glassy matrix is evidenced from the transmission electron microscopy (TEM) analyses. The UV–vis–NIR absorption spectra shows 10 bands corresponding to ⁴I_13/2, ⁴I_11/2, ⁴I_9/2, ⁴F_9/2, ⁴S_3/2, ²H_11/2, ⁴F_7/2, ⁴F_5/2, ²G_9/2, ⁴G_11/2 transitions in which the most intense bands are ²H_11/2 and ⁴G_11/2. The absorption spectrum of Er³⁺ ions free glass sample containing Ag NPs displays a prominent surface Plasmon resonance (SPR) band located at 528 nm. The infrared to visible frequency upconversion (UC) emission under 797 nm excitation shows two emission bands green (⁴S_3/2–⁴I_15/2) and red (⁴F_9/2–⁴I_15/2) centered at 540 nm and 634 nm, respectively, corresponding to Er³⁺ transitions. An enhancement in UC emission intensity of green band (⁴S_3/2–⁴I_15/2) is observed in the presence of silver NPs and the maximum enhancement occurred for 1.5 mol% AgCl. However, the enhancement of emission intensity of the red band (⁴F_9/2–⁴I_15/2) is smaller. The enhancement of UC emission is understood in terms of the intensified local field effect due to silver NPs.     

Naturally occurring himachalenes to benzocycloheptene amino vinyl bromide derivatives: as antidepressant molecules

A new series of benzocycloheptene amino vinyl bromide derivatives (9a-9m) were synthesized from isomeric mixture of himachalenes through two-step synthesis. The unusual structure of benzocycloheptene amino vinyl bromide derivative (9a) was confirmed by NMR and X-ray crystallography analyses. The newly synthesized amino vinyl bromide derivatives of benzocycloheptene were further evaluated for their antidepressant activities. The compound 9c had shown significant reduction in the immobility period.     

Eye‐Catching Dual‐Fluorescent Dynamic Metal–Organic Framework Senses Traces of Water: Experimental Findings and Theoretical Correlation

A guest‐dependent dynamic fivefold interpenetrated 3D porous metal–organic framework (MOF) of Zn^II ions has been synthesized that exhibits selective carbon dioxide adsorption. Furthermore, the MOF shows excellent luminescence behavior, which is supported by a systematic study on the guest‐responsive multicolor emission of a suspension of the MOF. The dual‐emission behavior arises from the excited‐state intramolecular proton transfer (ESIPT), and the compound also shows remarkable potential to detect traces of water in various organic solvents. The experimental observations were also painstakingly authenticated by using time‐dependent density‐functional‐theory (DFT) calculations.