Probing substrate binding inside a paramagnetic cavity: a NMR spectroscopy toolbox for combined experimental and theoretical investigation.

Protein cavities often rely on the paramagnetic metal present in their active site in order to catalyse various chemical transformations in biology. The selective detection and identification of the substrate is of fundamental importance in environmental monitoring and biological studies. Herein, a covalently linked Fe(iii)porphyrin dimer-based paramagnetic sensory cavity has been devised for the accurate detection and simultaneous identification of phenol (substrate) binding within the cavity that provides a unique spectroscopic signature with valuable structural and environmental information.

Nature inspired synthesis of magnetite nanoparticle aggregates from natural berthierine.

We investigate the origin of the magnetite nanoparticle aggregates (MNAs) from the Peña Colorada iron-ore mining district (Mexico) to devise a nature inspired synthesis process. Three types of samples were used: natural MNAs recovered from the mine, concentrated magnetite microparticles as reference material, and thin berthierine films used to synthesize MNAs. The chemical, mineralogical, crystallographic and rock magnetic properties were determined by polarized microscopy, high-resolution transmission electron microscopy, electron microprobe, X-ray diffraction, Mössbauer spectroscopy, and thermomagnetic and hysteresis measurements.

A palladium catalyzed asymmetric desymmetrization approach to enantioenriched 1,3-disubstituted isoindolines.

Herein, we report the first palladium/MPAA catalyzed enantioselective C-H activation/[4 + 1] annulation of diarylmethyltriflamide and olefins to construct chiral -1,3-disubstituted isoindoline derivatives. The use of a readily accessible mono-N-protected amino acid as a chiral ligand improves the efficiency and enantioselectivity of the catalytic transformation. The developed method provides access to both enantiomers of a product using either d or l-phenylalanine derivative as a chiral ligand facilitating the synthesis of both optically active 1,3-disubstituted isoindoline derivatives.

Modulation of supramolecular chirality by stepwise axial coordination in a nano-size trizinc(ii)porphyrin trimer.

Herein, we report a chiral guest's triggered spring-like contraction and extension motions coupled with unidirectional twisting in a novel flexible and 'nano-size' achiral trizinc(ii)porphyrin trimer host upon step-wise formation of 1 : 1, 1 : 2, and 1 : 4 host-guest supramolecular complexes based on the stoichiometry of the diamine guests for the first time. During these processes, porphyrin CD responses have been induced, inverted, and amplified, and reduced, respectively, in a single molecular framework due to the change in the interporphyrin interactions and helicity. Also, the sign of the CD couplets is just the opposite between and substrates which suggests that the chirality is dictated solely by the stereographic projection of the chiral center.

Ruthenium-catalyzed formal sp C-H activation of allylsilanes/esters with olefins: efficient access to functionalized 1,3-dienes.

Ru-catalysed oxidative coupling of allylsilanes and allyl esters with activated olefins has been developed isomerization followed by C(allyl)-H activation providing efficient access to stereodefined 1,3-dienes in excellent yields. Mild reaction conditions, less expensive catalysts, and excellent regio- and diastereoselectivity ensure universality of the reaction. In addition, the unique power of this reaction was illustrated by performing the Diels-Alder reaction, and enantioselective synthesis of highly functionalized cyclohexenone and piperidine and finally synthetic utility was further demonstrated by the efficient synthesis of norpyrenophorin, an antifungal agent.

Tight-binding investigation of the structural and vibrational properties of graphene-single wall carbon nanotube junctions.

Hybrid carbon nanostructures based on single walled carbon nanotubes (SWNTs) and single layer graphene (SLG) have drawn much attention lately for their applications in a range of efficient hybrid devices. A few recent studies, addressing the interaction behavior at the heterojunction, considered charge transfer between the constituents (SWNTs and SLG) to be responsible for changes in the electronic and vibrational properties of their hybrid system. We report the effect of various factors, arising due to the interactions between the atoms of SWNTs and SLG, on the structural and vibrational properties of hybrid nanostructures investigated computationally within the framework of tight-binding DFT.

Three-dimensional nickel vanadium layered double hydroxide nanostructures grown on carbon cloth for high-performance flexible supercapacitor applications.

This study reports the synthesis of ultrathin Ni-V layered double hydroxide nanosheets on carbon cloth (NVL@CC) through adopting a facile and cost-effective method for flexible supercapacitor applications. The as-synthesized NVL@CC possesses a uniform, mechanically strong and highly ordered porous network with connected pores, ensuring high specific capacitance and enhanced cyclability. A high specific capacity of 1226 C g (2790 F g) was obtained at 1 A g, and it remained at 430 C g (1122 F g) even at a higher current density of 10 A g.

Surface modification and pattern formation by nucleobases and their coordination complexes.

This review presents recent progress concerning the organization of nucleobases on highly ordered pyrolytic graphite (HOPG), mica, Cu(110) and Au(111) surfaces, followed by their studies using microscopy methods such as atomic force microscopy (AFM), scanning tunneling microscopy (STM) and transmission electron microscopy (TEM). Interesting research prospects related to surface patterning by nucleobases, nucleobase-functionalized carbon nanotubes (CNTs) and metal-nucleobase coordination polymers are also discussed, which offer a wide array of functional molecules for advanced applications. Nucleobases and their analogs are able to invoke non-covalent interactions such as π-π stacking and hydrogen bonding, and possess the required framework to coordinate metal ions, giving rise to fascinating supramolecular architectures.

Visible-light-driven photocatalytic degradation of safranin-T dye using functionalized graphene oxide nanosheet (FGS)/ZnO nanocomposites.

Photocatalysts suffer from a lack of separation of photogenerated excitons due to the fast recombination of charge carriers, so a strong synergistic effect exhibited by photocatalysts is promising for effective photocatalysis. Herein, we have synthesized efficient visible light functionalized graphene oxide nanosheet (FGS)/ZnO nanocomposite photocatalysts a simple and economical approach with large scale production for practical applications. A series of nanocomposites (FGS/ZnO NCs) with different amounts by weight of graphene oxide (GO) have been synthesized a facile solution route followed by calcination under environmental conditions.

One-Step Fabrication of Microchannels Lined with a Metal Oxide Coating.

We demonstrate a simple, single-step method for metal/metal oxide coating on interior walls of microchannels in an elastomeric material like PDMS, which is the mainstay of microfluidic devices. The fabrication process involves electrodeposition of cuprous oxide on a metallic wire or a sheet, embedding it inside a PDMS matrix along with the cross-linker, curing and then swelling the PDMS elastomer, and finally pulling out the template metal wire or the metal sheet from the PDMS matrix. Stronger attachment of the metal oxide layer to PDMS allows the transfer of the metal oxide coating originally present on the template surface (wire or sheet) to the channel wall resulting in a microchannel/microslit lined with the metal/metal oxide layer.

Hydrogen-Bonding Interactions Trigger a Spin-Flip in Iron(III) Porphyrin Complexes.

A key step in cytochrome P450 catalysis includes the spin-state crossing from low spin to high spin upon substrate binding and subsequent reduction of the heme. Clearly, a weak perturbation in P450 enzymes triggers a spin-state crossing. However, the origin of the process whereby enzymes reorganize their active site through external perturbations, such as hydrogen bonding, is still poorly understood.

Synthesis of isofagomine-pyrrolidine hybrid sugars and analogues of (-)-steviamine and (+)-hyacinthacine C5 using 1,3-dipolar cycloaddition reactions.

Highly regioselective 1,3-dipolar cycloadditions between d-arabinose-derived nitrones and d-mannitol-derived trans-olefins have been utilized to synthesize isofagomine-pyrrolidine hybrid sugars, hydroxymethylated analogues of (-)-steviamine and analogues of (+)-hyacinthacine C5. All of the new compounds were subsequently tested against several commercially available glycosidases, and some of them showed good and selective glycosidase inhibition.

Towards Using Molecular States as Qubits.

Molecular systems are presented as possible qubit systems by exploring non-resonant molecular fragmentation of n-propyl benzene with femtosecond laser pulses as a model case. We show that such laser fragmentation process is dependent on the phase and polarization characteristics of the laser. The effect of the chirp and polarization of the femtosecond pulse when applied simultaneously is mutually independent of each other, which makes chirp and polarization as useful 'logic' implementing parameters for such molecular qubits.

Characterization of nanostructured PZT prepared by chemical routes.

Nanostructured, crystalline Pb(Zr0.52Ti0.48)O3 (crystallite size 8-10 nm) ceramic powders were synthesized at low temperature by the hydroxide co-precipitation and aqueous solution method (water bath technique).