Photosensitivity,substituent and solvent-induced shifts in UV-visible absorption bands of naphthyl-ester liquid crystals: a comparative theoretical approach

The substituent- and solvent-induced shifts in UV-visible absorption bands of naphthyl-ester nematic liquid crystals, viz., 4-octylphenyl-6-octyloxy-2-naphthoate (NAPHE1) and 6-octyloxy-2-naphthylyl-4-octyloxybenzoate (NAPHE2), have been investigated using the DFT, CNDO/S and INDO/S methods. A correlation has been made between molecular charge distribution and phase stability based on Mulliken, Loewdin, AM1, PM3, MNDO, CNDO/S and INDO/S methods. The observed π→π* and n→π* electronic transitions have been reported. The substituent- and solvent-induced shifts in absorption bands, transition energies and energy gaps have been discussed. The photosensitivity of the molecules has been analysed based on these shifts. It has been observed that the substituent has a dominant role on both absorption maxima and energy band gap, whereas the solvent has a dominant role only on absorption maxima, and no effect has been observed on the energy gap. These shifts may provide beneficial consequences in determining the end use of compounds.     

Water-Mediated Synthesis of Benzazole and Thiourea Motifs by Reacting Naturally Occurring Isothiocyanate with Amines

An efficient, green, and facile method has been developed for the synthesis of benzazole and thiourea analogues from naturally occurring erucin in moderate to good yields. The reaction was carried out in water without using any metal catalyst or base. The present method tolerated the various functional groups on aromatic rings and also applicable for other isothiocyanates.     

Noria: A Highly Xe‐Selective Nanoporous Organic Solid

Separation of xenon and krypton is of industrial and environmental concern; the existing technologies use cryogenic distillation. Thus, a cost‐effective, alternative technology for the separation of Xe and Kr and their capture from air is of significant importance. Herein, we report the selective Xe uptake in a crystalline porous organic oligomeric molecule, noria, and its structural analogue, PgC‐noria, under ambient conditions. The selectivity of noria towards Xe arises from its tailored pore size and small cavities, which allows a directed non‐bonding interaction of Xe atoms with a large number of carbon atoms of the noria molecular wheel in a confined space.     

An Ultra-Microporous Metal–Organic Framework with Exceptional Xe Capacity

Molecular confinement plays a significant effect on trapped gas and solvent molecules. A fundamental understanding of gas adsorption within the porous confinement provides information necessary to design a material with improved selectivity. In this regard, metal–organic framework (MOF) adsorbents are ideal candidate materials to study confinement effects for weakly interacting gas molecules, such as noble gases. Among the noble gases, xenon (Xe) has practical applications in the medical, automotive and aerospace industries. In this Communication, we report an ultra-microporous nickel-isonicotinate MOF with exceptional Xe uptake and selectivity compared to all benchmark MOF and porous organic cage materials. The selectivity arises because of the near perfect fit of the atomic Xe inside the porous confinement. Notably, at low partial pressure, the Ni–MOF interacts very strongly with Xe compared to the closely related Krypton gas (Kr) and more polarizable CO₂. Further ¹²⁹Xe NMR suggests a broad isotropic chemical shift due to the reduced motion as a result of confinement.     

Rhodium(III) catalyzed synthesis of isoquinolone fused azabicycles through C–H activation of N-pivaloyloxy benzamides

Herein we describe an efficient one pot strategy toward highly functionalized isoquinolone fused azabicycles having great synthetic potential via C–H activation of N-pivaloyloxy benzamides under very mild conditions. The reaction is accomplished at room temperature within one hour in good to excellent yields and is found to be compatible with a range of diazabicyclic olefins and benzamides. The present strategy offers an easy route for the synthesis of biologically relevant compounds which possess multiple points for divergent synthesis. N–N bond cleavage of synthesized compounds may enable their significant role as effective precursors for the preparation of diaminocyclopentane fused isoquinolones.     

Structural designing,spectral and computational studies of bioactive Schiff's base ligand and its transition metal complexes

Transition metal complexes of Mn(II) and Ni(II) have been synthesized with novel bioactive Schiff's base ligand. Schiff's base ligand i.e. benzoylacetone‐bis(2‐amino‐4‐methylbenzothioazole) has been synthesized via condensation reaction between 2‐amino‐4‐methylbenzothioazole and benzoylacetone in 2:1 ratio, respectively. Synthesized ligand has been characterized using elemental analysis, infra‐red, ¹H–NMR and mass spectroscopy techniques. Characterization of complexes was based on magnetic moment, molar conductance, elemental analysis, electronic spectra, infra‐red and EPR spectroscopic techniques. Molar conductance data suggest that metal complexes are non‐electrolytic in nature. Therefore, these complexes are formulated as [M(L)X₂], where M = Mn(II), Ni(II), L = Schiff's base ligand, X = Cl^?, CH₃COO^?, NO₃^?. Data of characterization study suggest octahedral geometry for Mn(II) and Ni(II) complexes. Geometry of metal complexes was also optimized with the help of computational study i.e. molecular modelling. Computational study also suggests octahedral geometry for complexes. Free ligand as well as its all metal complexes have been screened against the growth of pathogenic bacteria (E.coli, S.aureus) and fungi (C.albicans, C.krusei, C.parapsilosis, C.tropicalis) to assess their inhibition potential. The inhibition data revealed that metal complexes exhibit higher inhibition potential against the growth of bacteria and fungi microorganisms than free ligand.