N-methylferrocenyl-N-ethylhydroxy ammonium nitrate: synthesis,characterization, and sensitizer in dye-sensitized solar cells

Transition Metal Chemistry - A new ferrocene-containing hydronitrate salt with formula N-methylferrocenyl-N-ethylhydroxy ammonium nitrate has been synthesized and characterized using microanalyses,...     

Catalytic activity of Mn(III) and Co(III) complexes: evaluation of catechol oxidase enzymatic and photodegradation properties

We have synthesized two mononuclear complexes, Mn-hq and Co-hq, to serve as sustainable catalysts (for degrading dyes from organic pollutant) and as biocatalysts (for promoting oxidation of catechol to quinone). The two complexes have been characterized by various spectroscopic tools, and with the assistance of single-crystal X-ray diffraction data, their molecular structures were established. The present complexes were exploited for the catalytic activity, i.e., enzymatic activity and photocatalytic property. In methanolic solution, Mn-hq and Co-hq were examined for catecholase-like activity and Mn-hq particularly catalyzes the oxidation of 3,5-di-tert-butyl catechol to analogous quinone with a K_cat value of 835.2 h^?1. Additionally, Mn-hq and Co-hq demonstrated remarkable photocatalytic activity for the degradation of methylene blue (MB) in the aqueous medium beneath visible light. Co-hq shows excellent stability and recyclability toward MB. Further, trapping experiment along with degradation pathways is also explored. Thus, the present research throws light on the excellent catalytic properties of simply designed complexes and this activity can be tuned for desired efficiencies in future prospects.

     

Comprehensive Review on Application of FTIR Spectroscopy Coupled with Chemometrics for Authentication Analysis of Fats and Oils in the Food Products

Currently, the authentication analysis of edible fats and oils is an emerging issue not only by producers but also by food industries, regulators, and consumers. The adulteration of high quality and expensive edible fats and oils as well as food products containing fats and oils with lower ones are typically motivated by economic reasons. Some analytical methods have been used for authentication analysis of food products, but some of them are complex in sampling preparation and involving sophisticated instruments. Therefore, simple and reliable methods are proposed and developed for these authentication purposes. This review highlighted the comprehensive reports on the application of infrared spectroscopy combined with chemometrics for authentication of fats and oils. New findings of this review included (1) FTIR spectroscopy combined with chemometrics, which has been used to authenticate fats and oils; (2) due to as fingerprint analytical tools, FTIR spectra have emerged as the most reported analytical techniques applied for authentication analysis of fats and oils; (3) the use of chemometrics as analytical data treatment is a must to extract the information from FTIR spectra to be understandable data. Next, the combination of FTIR spectroscopy with chemometrics must be proposed, developed, and standardized for authentication and assuring the quality of fats and oils.     

Effect of Bulky Functional Groups on Donor and Acceptor Interactions and their Photoluminescence Properties

Material designs that use donor and acceptor units are often found in organic optoelectronic devices. Molecular level insight into the interactions between donors and acceptors are crucial for understanding how such interactions can modify the optical properties of the organic optoelectronic materials. In this paper, tris(4-(tert-butyl)phenyl)amine (pTPA) was synthesized as a donor in order to compare with unmodified triphenylamine (TPA) in a donor–acceptor system by having 2,4,6-triphenyl-1,3,5-triazine (TRZ) as an acceptor. Dimerization of donors and acceptors occurred in solvent when the concentration of solute is high. At 0 K, using a polarizable continuum model, the nitrogen atom of TPA is found to stack on top of the center of triazine of TRZ, whereas such alignment is offset in pTPA and TRZ. We attributed such alignment in TPA-TRZ as the result of attractive interactions between partial localization of 2p_z electrons at the nitrogen atom of TPA and the π deficiency of triazine in TPA-TRZ. By taking into account random motions of the solvent effect at 300 K in quantum molecular dynamics and classical molecular dynamics simulations to interpret the marked difference in emission spectra between TPA-TRZ and pTPA-TRZ, it was revealed that the attractive interaction between pTPA and TRZ in toluene is weaker than TPA and TRZ. Because of the weaker attractive interaction between pTPA and TRZ in toluene, the dimers adopted numerous ground state conformations resulting in broad emission bands superimposed with multiple small Gaussian peaks. This is in contrast to TPA-TRZ which has only one dominant dimer conformation. This study demonstrates that the strength of intermolecular interactions between donors and acceptors should be taken into consideration in designing supramolecular structures.     

LDH-intercalated d-gluconate: Generation of a new food additive-inorganic nanohybrid compound

Intercalation of d-gluconate into the interlamellae of zinc-aluminum-layered double hydroxide for the formation of a food additive-inorganic layered nanohybrid was accomplished by both direct (co-precipitation) and indirect (ion-exchange) methods. Powder X-ray diffraction (PXRD) together with CHNS and Fourier transform infrared (FTIR) analyses showed that the hybridization of d-gluconate with pure phase and good crystallinity was successfully accomplished by a direct method within ranges of pH 7.5-10, Zn to Al initial molar ratio of 2-5 and DG concentration of 0.05-0.3 M. The same nanohybrid compound was also prepared using an indirect ion-exchange method by contacting the pre-prepared LDH with 0.1 M DG for 80 min. The basal spacing of the nanohybrid synthesized by the direct method ranged between 9 and 12.0 Å while that synthesized by the indirect ion-exchange method was 14.0 Å. The crystallinity of the latter was higher than the former and it inherited the crystallinity of the precursor. This work shows that a food additive, such as d-gluconate, can be hybridized into an inorganic host for the formation of a new nanohybrid compound, which can be used to regulate the release of acidity in the food industry.     

Nickel(II) complexes bearing pyrazolylpyridines: synthesis,structures and ethylene oligomerization reactions

Reactions of 2‐bromo‐6‐(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)pyridine ( L1 ) and 2,6‐bis(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)pyridine ( L2 ) with NiCl₂ and NiBr₂ led to the formation of their respective metal complexes [NiCl₂(L1)] ( 1 ), [NiBr₂(L1)] ( 2 ) and [NiBr₂(L2)] ( 3 ) in moderate to high yields. The complexes were characterized using elemental analyses, mass spectrometry and single‐crystal X‐ray diffraction for 2 . The solid‐state structure of 2 confirmed the bidentate coordination mode of L1 and formation of a monometallic compound. Activation of the nickel(II) pre‐catalysts with methylaluminoxane afforded active catalysts in the ethylene oligomerization reaction to produce mainly butenes (84–86%). In contrast, activation of nickel(II) pre‐catalyst 2 with ethylaluminium dichloride resulted in partial Friedel–Crafts alkylation of the toluene solvent by the preformed oligomers. Complex structure, nature of co‐catalyst employed, type of solvent and reaction conditions influenced the catalytic behaviour of these pre‐catalysts. Copyright © 2015 John Wiley & Sons, Ltd.     

High-performance 850 nm vertical-cavity surface-emitting laser in Gigabit Ethernet network

High-performance oxide vertical-cavity surface-emitting (VCSEL) laser is fabricated, and its usefulness is demonstrated as a suitable transmitting light source at 850 nm operating wavelength for Gigabit Ethernet application. Utilization of barrier reduction layers reveals low-threshold current requirement for operation at high modulation bandwidth. The electrical and optical characteristics, measured from the fabricated VCSEL, are simulated for Gigabit Ethernet transmission. Data rates of 1.25 Gbps with a bit error rate of 10⁻¹¹ are achieved by the use of a specific multimode network simulator.     

Analysis of two neutron (proton) transfer reaction data in the Zr-region

The spectroscopic amplitudes, form factors, angular distributions and total cross-sections for two nucleon transfer reactions in Zr-region in the zero range distorted wave Born approximation are calculated using consistent set of shell model wave functions. A single normalisation factor gives a good fit to all the two neutron transfer reaction data whereas the corresponding fit for the two-proton transfer reaction data is less satisfactory.     

Supramolecular assembly of strongly chemisorbed size- and shape-defined chiral clusters: S- and R-alanine on Cu(110)

The bonding and self-assembly of a chirally organized monolayer of alanine on the Cu(110) surface has been investigated using reflection-absorption infrared spectroscopy, low-energy electron diffraction (LEED), and scanning tunneling microscopy (STM). This multitechnique approach has enabled an in-depth understanding of the hierarchy of chirality transfer: from a single adsorbed molecule, to size-defined chiral clusters, and then to an overall chiral assembly. The data have indicated that the alanine is in its anionic form, bound to the copper surface through the oxygens of the ionized carboxylate group and the nitrogen of the neutral amino group. Importantly, the methyl group is held away from the surface, resulting in direct chirality transfer into the footprint of the adsorbed alanine molecules, with the local adsorption motif for S-alanine being the mirror image of that created for R-alanine. STM has shown that S-alanine molecules self-organize to form size-defined chiral clusters of six or eight molecules at the surface, interspersed with chiral channels of bare metal. Together, these clusters and channels further self-assemble into a chiral array with one unique chiral domain sustained across the entire surface. A similar chiral assembly, but with the mirror organization, has been observed for R-alanine. Structural models for the individual clusters are proposed, and in conjunction with LEED data, overall models for these chiral phases of both S- and R-alanine have been constructed. Overall, this adsorption system has been found to be both strongly chemisorbed and capable of extensive intermolecular H-bonding, causing stresses that lead not only to the chiral self-organization of molecules but also to a specific self-organization of the empty chiral channels and spaces that intersperse the structure which, in turn, chirally assemble across macroscopic length scales to give a surface with global organizational chirality.     

Synthesis of a cyclic peptide containing norlanthionine: effect of the thioether bridge on peptide conformation

Two diastereomeric analogues of ring C of nisin incorporating a novel norlanthionine residue have been synthesized via a triply orthogonal protecting group strategy. A full structural study was carried out by NMR, which elucidated the conformational properties of the two peptides and enabled the identity of each diastereoisomer to be proposed.