Immobilization of lactate dehydrogenase on tetraethylorthosilicate-derived sol-gel films for application to lactate biosensor

Tetraethylorthosilicate (TEOS)-derived sol-gel films were utilized for the immobilization of lactate dehydrogenase (LDH) by physical adsorption and sol-gel/LDH/sol-gel sandwich configuration. An attempt was made to ascertain the optimum pH and temperature for the immobilized LDH. It was shown that TEOS-derived sol-gel films containing physically adsorbed LDH exhibited linearity from 0.5 to 4 mM, whereas those containing LDH in sandwich configuration showed linearity from 0.5 to 3 mM l-lactate. These sol-gel films, immobilized with LDH, were found to be stable for about 4 weeks at 4–10°C.     

High-rate LDPC codes from partially balanced incomplete block designs

Journal of Algebraic Combinatorics - This paper presents a combinatorial construction of low-density parity-check (LDPC) codes from partially balanced incomplete block designs. Since...     

Conductive Metal-Organic Frameworks: Electronic Structure and Electrochemical Applications

Smarter and minimization of devices are consistently substantial to shape the energy landscape. Significant amounts of endeavours have come forward as promising steps to surmount this formidable challenge. It is undeniable that material scientists were contemplating smarter material beyond purely inorganic or organic materials. To our delight, metal-organic frameworks (MOFs), an inorganic-organic hybrid scaffold with unprecedented tunability and smart functionalities, have recently started their journey as an alternative. In this review, we focus on such propitious potential of MOFs that was untapped over a long time. We cover the synthetic strategies and (or) post-synthetic modifications towards the formation of conductive MOFs and their underlying concepts of charge transfer with structural aspects. We addressed theoretical calculations with the experimental outcomes and spectroelectrochemistry, which will trigger vigorous impetus about intrinsic electronic behaviour of the conductive frameworks. Finally, we discussed electrocatalysts and energy storage devices stemming from conductive MOFs to meet energy demand in the near future.     

Identity of the exchangeable sulfur-containing ligand at the Mo(V) center of R160Q human sulfite oxidase

In our previous study of the fatal R160Q mutant of human sulfite oxidase (hSO) at low pH (Astashkin et al. J. Am. Chem. Soc.2008, 130, 8471-8480), a new Mo(V) species, denoted "species 1", was observed at low pH values. Species 1 was ascribed to a six-coordinate Mo(V) center with an exchangeable terminal oxo ligand and an equatorial sulfate group on the basis of pulsed EPR spectroscopy and (33)S and (17)O labeling. Here we report new results for species 1 of R160Q, based on substitution of the sulfur-containing ligand by a phosphate group, pulsed EPR spectroscopy in K(a)- and W-bands, and extensive density functional theory (DFT) calculations applied to large, more realistic molecular models of the enzyme active site. The combined results unambiguously show that species 1 has an equatorial sulfite as the only exchangeable ligand. The two types of (17)O signals that are observed arise from the coordinated and remote oxygen atoms of the sulfite ligand. A typical five-coordinate Mo(V) site is compatible with the observed and calculated EPR parameters.     

Porphyrin-functionalised rotaxanes for anion recognition

The synthesis and anion-recognition properties of two new porphyrin-functionalised [2]rotaxane host molecules are described. The rotaxane compounds are prepared via a chloride-anion-templated clipping strategy. (1)H NMR titration experiments demonstrate that the rotaxane host systems exhibit high binding affinities and general selectivities for chloride anions in DMSO-d(6) or CDCl(3)/CD(3)OD solvent systems. UV-visible and fluorescence spectroscopy experiments reveal that the rotaxane receptors are ineffective as optical anion sensors. However, both receptors are shown to be capable of detecting chloride anions electrochemically via cathodic shifts in the porphyrin P/P(+) redox couples.     

FT-IR, FT-Raman and quantum chemical calculations of (E)-N-carbamimidoyl-4-((3,4-dimethoxybenzylidene) amino) benzenesulfonamide

FT-IR and FT-Raman spectra of (E)-N-carbamimidoyl-4-((3,4-dimethoxybenzylidene) amino) benzenesulfonamide were recorded and analyzed. The vibrational wavenumbers were computed using HF/6-31G*, B3PW91/6-31G* and B3LYP/6-31G* basis. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands obtained experimentally. The results indicate that the B3LYP method is able to provide satisfactory results for predicting vibrational frequencies and structural parameters. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of non-linear optics. The geometrical parameters of the title compound are in agreement with that of similar derivatives.     

FT-IR, FT-Raman spectroscopy and computational study of (E)-4-((anthracen-9-ylmethylene)amino)-N-carbamimidoylbenzene sulfonamide

The infrared and Raman spectra of (E)-4-((anthracen-9-ylmethylene)amino)-N-carbamimidoylbenzene sulfonamide have been recorded and analysed. Geometry and harmonic vibrational wavenumbers were calculated theoretically using Gaussian03 set of quantum chemistry codes. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands found in infrared and Raman spectra of the studied molecule. The red-shift of the NH stretching band in the infrared spectrum from the computed wavenumber indicates the weakening of the NH bond. The NH stretching band has split into a doublet in the IR spectrum owing to the Davydov coupling between neighbouring units. The geometrical parameters of the title compound are in agreement with the reported similar derivatives. The calculated first hyperpolarizability is comparable with the reported value of similar structures and may be an attractive object for further studies on non-linear optics. The important thermodynamical parameters are also reported.     

Ionic liquid catalyzed one-pot multi-component synthesis of fused pyridine derivatives: A strategy for green and sustainable chemistry

The synthesis of a combinatorial library of heterocycle-fused pyridine derivatives has been achieved successfully via a one-pot four-component reaction of aromatic/aliphatic aldehyde, malononitrile, thiazolidine-2,4-dione and ammonium acetate in the presence of piperidinium acetate as the catalyst. It involved the Knoevenagel condensation of the aldehyde and malononitrile to produce arylidene malononitrile as an intermediate, which was further intramolecular cyclization through Michael type addition ketone to the electrophilic double bond of the arylidene to produce fused pyridines in high yields. Environmental friendliness, low cost, Operational simplicity, extensive reusability and applicability, and easy recovery of the catalyst using simple evaporation are the critical features of this methodology. Also, a series of pyridine based dihydrothiazolo[4,5-b] pyridine-6-carbonitrile analogs were synthesized and selected for their in vitro antifungal and antibacterial activities.     

Chemoenzymatic synthesis of piperoxan,prosympal, dibozane,and doxazosin

The synthesis of both enantiomers of 1,4-benzodioxan-2-carboxylic acid 1, a key synthetic intermediate for the therapeutic agents piperoxan, prosympal, dibozane, and doxazosin was achieved with good yields and high enantioselectivities via the Arthrobacter sp. lipase catalyzed kinetic resolution of ester (±)-17a. The influence of the co-solvents and the immobilization of the lipase upon kinetic resolution demonstrated that immobilized whole cells, in the presence of n-butanol as a co-solvent, resulted in the optimal resolution of the substrate (ee ～99%, E = 535) at 258 mmol (50 g/L) substrate concentration.