Facile one-pot synthesis of aromatic and heteroaromatic sulfonamides

A series of arene and heteroarene sulfonamides were prepared in one vessel from aryl and heteroaryl bromides via conversion into the corresponding Grignard reagents using either magnesium or isopropylmagnesium chloride and subsequent reaction with sulfur dioxide, sulfuryl chloride, and an amine.     

Synthesis,crystal feature and spectral characterization of paeonol derived Schiff base ligands and their Cu(II) complexes with antimicrobial activity

Four novel Schiff bases PNL-4OMe, PNL-4Br, PNL-4F, PNL-3,4-F₂, and their copper(II) complex with [M(L)₂(H₂O)₂] arrangement was synthesized using Paeonol and various aromatic substituted amines. Characterization has been done through FT-IR, ESI Mass, TG-DTA, DFT, magnetic measurements, elemental analysis, and Thermogravimetric analysis. Paeonol derived new bond formation in Schiff bases and changes in frequencies during complexation have been confirmed through FT-IR spectra. All complexes are thermally stable, paramagnetic, and have non-electrolytic behavior. The antimicrobial activity was also tested against Gram-positive bacteria; S. aureus, B. subtilis, and Gram-negative bacteria; E. coli, P. aeruginosa. Single-crystal X-ray data provide evidence that PNL-3,4-F₂ is recrystallizing in a triclinic system with P-1(2) space group and confirms the intramolecular H-bonding and short Vander Waal type interactions. Non-covalent interactions and π … π stacking surface interactions in PNL-3,4-F₂ were studied with Hirshfeld analysis. H-atoms have the highest interactions with other atoms of neighbouring molecules compared to all other atoms. DFT calculations were performed on the electronic structure of ligand PNL-3,4-F₂ and its copper(II) complex and discussed.     

Structural and electrical properties of sol–gel grown (1 − x) (ZnO) + (x) (SnO2) (x = 0, 0.25, 0.5) nanocomposites

Journal of Sol-Gel Science and Technology - Semiconducting oxide nanocomposites of ZnO/SnO2 with different weight ratio, i.e. (i) ZnO:SnO2?=?100:0 (ZnO0), (ii)...     

A simple and efficient approach for the synthesis of 2-aminated quinazoline derivatives via metal free oxidative annulation

A simple and efficient approach for the synthesis of 2-aminoquinazoline derivatives in moderate to good yields. This reaction employs mild reaction conditions, is metal-free and utilizes readily available starting materials making it a more viable reaction for scale up synthesis and ligand diversity. Notably, this methodology allows for the synthesis of 2-aminoquinazolines using a free amine or cyclic amine enabling structural diversity and good atom economy.     

Enantioselective catalysis of the Henry reaction by a chiral macrocyclic ytterbium complex in aqueous media

A chiral macrocyclic ytterbium cationic complex catalyses the nitro-aldol reaction between alpha-ketocarboxylates and nitromethane under ambient aqueous conditions, leading to the formation of for example, methyl-2-hydroxy-2-methyl-3-nitropropanoate in 96% yield and 59% enantiomeric purity. Monitoring of the paramagnetically shifted intermediate Yb species by (1)H NMR allows several different species on the catalytic cycle to be identified and is consistent with the intermediacy of stereoisomeric chelated pyruvates of differing reactivity towards the nucleophile, as well as product inhibition of turnover.     

Application of Modified Kick's Law to Rhombohedral Crystals: Calcite

Optical study of mechanical response indicated by Knoop indentation of cleavage faces of natural rhombohedral clacite crystals based on MEYER'S law/KICK'S law (P adⁿ) and also on modified KICK'S law (P–W) = bd² is made. The response of cleavage faces for low load region (LLR) and high load region (HLR) of applied loads P to produce indentation mark of longer diagonal length is different. In LLR the Newtonian resistance pressure W is negative and varies with orientation and quenching temperature whereas in HLR it is positive and almost constant at room temperature and quenching temperatures. In LLR, W indicates crystal anisotropy. The values of resistance pressure W₂ and standard hardness b₂ in HLR are independent on thermal treatment and are constant within experimental limits. Since they are independent on indenter orientations, they are not associated with crystal anisotropy.     

Studies on transport properties of copper doped tungsten diselenide single crystals

During recent years, transition metal dichalcogenides of groups IVB, VB and VIB have received considerable attention because of the great diversity in their transport properties. 2H-WSe₂ (Tungsten diselenide) is an interesting member of the transition metal dichalcogenide (TMDC's) family and known to be a semiconductor useful for photovoltaic and optoelectronic applications. The anisotropy usually observed in this diamagnetic semiconductor material is a result of the sandwich structure of Se-W-Se layers interacting with each other, loosely bonded by the weak Van der Waals forces. Recent efforts in studying the influence of the anisotropic electrical and optical properties of this layered-type transition metal dichalcogenides have been implemented by doping the samples with different alkali group elements. Unfortunately, little work is reported on doping of metals in WSe₂. Therefore, it is proposed in this work to carry out a systematic growth of single crystals of WSe₂ by doping it with copper in different proportions i.e. Cu_xWSe₂ (x=0, 0.5, 1.0) by direct vapour transport technique. Transport properties like low and high temperature resistivity measurements, high pressure resistivity, Seebeck coefficient measurements at low temperature and Hall Effect at room temperature were studied in detail on all these samples. These measurements show that tungsten diselenide single crystals are p-type whereas doped with copper makes it n-type in nature. The results obtained and their implications are discussed in this paper.     

One pot synthesis of diarylpyrido[3,2‐c]coumarins

Various diarylpyrido[3,2‐c]coumarins 3a‐l have been synthesized in one step by reacting 4‐hydroxy coumarins 1a‐d with α,β‐unsaturated ketones 2a‐c in the presence of ammonium acetate and acetic acid under Kroehnke's reaction conditions.